Bachelor thesis (2015)
Earth sciences
The sorption of heavy
metals to biochar.
Author: Milan Besselink Student number: 10469850
Supervisor: Dr. B. Jansen Second supervisor: Dr. J.R. Parsons
2
Abstract
Biochar is a pyrogenic carbon-rich material and has been proposed as an effective and relatively cheap form of black carbon. It is produced by pyrolysis, which is the thermal decomposition of biomass in a closed system with little or no oxygen. Biochar is resistant to biological and chemical degradation and have a mean residence time of thousands of years in the soil. It has a porous structure and contains functional surface groups such as carboxylic, hydroxyl, phenolic and carbonyl. Therefore it can affect the pH, cation exchange capacity (CEC) and the retention of water and nutrients. Biochar can be used in sediment and soil amendment to reduce the bioavailability and therefore the risks of heavy metal contamination. The use of biochar as asorbent to remove metallic contaminants from aqueoussolutions is a promising wastewater treatmenttechnology. But, this still requires information on the sorption of heavy metals to biochar and also on whether this is affected by the presence of natural and contaminant organic compounds because of possible competition effects. The aim of this project is to study the sorption of Cu and Zn to two forms of biochar made at different temperatures and the potential effects of natural organic matter on this process.
3
Content page
1 Introduction
1.1 Key objective and relevance 5
1.2 Scientific background 5,6
2 Methods
2.1 Preparing the element solutions 7, 8
2.2 Preparing the dissolved organic matter solution 8
2.3 Sample preparation 8, 9
2.4 Sample analysis 9
2.5 Adsorption isotherm 9, 10
3 Results
3.1 Brown biochar single element 11, 12, 13
3.2 Black biochar single element 13, 14
3.3 Black competition 15, 16 3. 4 Brown competition 17, 18 3.5 TOC 19, 20 4 Discussion 4.1 Biochar 21 4.2 Solutions 21 4.3 Pipetting 21 4.4 Loss of samples 21 4.5 Controlling pH 21, 22 4.6 Adsorption isotherm 22
4.7 The parameters qm and Kl 22
4.8 results 22, 23
4 page 6 references 25 7 Appendix Appendix A 26, 27 Appendix B 27
5
1 Introduction
1.1 Key objective and relevance
Cu and Zn are heavy metals that are present in the environment. These heavy metals originating from wastewater irrigation, solid waste disposal, atmospheric deposition and pesticide application can accumulate in surface soil and have a potential to leach into groundwater (Liang, Y., et al, 2014). Even in relatively low concentrations these heavy metals are toxic to aquatic flora and fauna. Some metals can be assimilated, stored and concentrated by organisms. Untreated effluents may have an adverse impact on the environment. Heavy metals including Cu and Zn are toxic at high
concentrations (Mohan, D ., et al, 2007).
Biochar has been proposed as an effective and relatively cheap form of black carbon that can be used in sediment and soil amendment to reduce the bioavailability and therefore the risks of heavy metal contamination (Beesley et al. 2010, 2011). The removal of metals from wastewater by the application of biochar as a sorbent has also been studied (Yang and Jiang 2014). But, this still requires
information on the sorption of heavy metals to biochar and also on whether this is affected by the presence of natural and contaminant organic compounds because of possible competition effects (Trakal et al., 2011). The key objective of this project is to study the sorption of Cu and Zn to two forms of biochar made at different temperatures and the potential effects of natural organic matter on this process. In order to study the key objective research will be done to which type of biochar the highest sorption capacity has for heavy metals and to whether there are differences in effects of biochar in clear water compared to biochar suspended in a solution of natural dissolved organic matter. Also, research will be done to the effects of biochar on the bioavailability of the metals Cu and Zn in the absence and presence of dissolved organic matter.
1.2 Scientific background
Biochar is a pyrogenic carbon-rich material. It is produced by pyrolysis, which is the thermal decomposition of biomass in a closed system with little or no oxygen. The production of biochar is relatively cheap when agricultural residues such as crops are used. Because the main cost of biochar are related to the heating and machinery, which is just around $4 per gigajoule (Inyang et al., 2011). The use of biochar as alow-cost sorbent to remove metallic contaminants from aqueoussolutions is a promising wastewater treatmenttechnology(Mohan et al., 2007). Biochars produced from animal waste, wood and agricultural residues have been researched for their capacity to sorb different heavy metals. Furthermore, according Inyang et al. (2011) high-efficiency carbon-based sorbents for heavy metals can be produced with anaerobic digestion. This method provides benefits, such as producing renewable bioenergy through anaerobic digestion and pyrolysis and reducing waste management cost.
Biochar can be used in soil amendment to improve crop production, soil fertility and nutrient retention and it serves as a carbon stock. This biochar is resistant to biological and chemical degradation and have a mean residence time of thousands of years in the soil. It has a porous structure and contains functional surface groups such as carboxylic, hydroxyl, phenolic and carbonyl. Therefore it can affect the pH, cation exchange capacity (CEC) and the retention of water and nutrients, which are important soil properties (Uchima, M., et al., 2010). The chemical and physical properties of biochars can be significantly different depending on the pyrolysis conditions, biomass
6 source, and post- and pre- treatments. Furthermore, biochar can adsorb organic contaminants via two mechanisms. The mechanisms that biochar uses for this sorption are the surface adsorption on carbonized fractions and the partitioning into the residual organic fraction (Uchima, M., et al., 2010). In the surface adsorption mechanism, the π-systems of biochar have a large sorptive potential for aromatic sorbates via noncovalent electron donor-acceptor interactions that are different from hydrophobic interactions. The partitioning mechanism is used in biochar which is produced at low pyrolytic temperatures with high organic fractions (Uchima, M., et al., 2010). According Uchima, M., et al. (2010) depending on the carbon type and the solution composition, the mechanisms that biochar uses for the sorption of heavy metals are: the ionic exchange between ionisable protons at the surface of acidic carbon and metal cations, electrostatic interactions between metal cations and negatively charged carbon surface, and sorptive interaction involving delocalized π electrons of carbon. This interaction at delocalized π electrons is very important for metal sorption by basic carbon via coordination of d-electrons or proton exchange. Also, basic nitrogen groups and mineral impurities can act as additional adsorption sites of the carbonaceous materials. Furthermore, the surface charge density of the carbon and the metal ion speciation are both affected by the solution pH, which is an essential parameter (Uchima, M., et al., 2010).
7
2 Methods
2.1 Preparing the element solutions
The first step in this lab research was to determine the ratio of the amount of biochar and the amount of solution for a sample. This ratio is based on the ‘k’ values for Cu and Zn according to Chen, X., et al. (2011). With this ratio the total amount of solution was calculated. The second step was to prepare the Erlenmeyer’s for the solutions; there are single- and multi- element solutions of 2, 4 and 8 mmol/L. One 500 ml and eight 1000 ml volumetric flasks were cleaned by rinsing them three times with acetone followed by cleaning them with a brush, rinsing them three times with distilled water and blowing them dry. Eventually all the volumetric flasks were labelled.
For the Cu solutions a stock solution of 20 mmol/L was prepared by first weighing 3,4004 gram of copper(ll)chloride-dihydrate (merck 1.02733.0250) continued by dissolving the CuCl2 by adding
Elga-water up to 1000 ml in a 1000 ml volumetric flask. Subsequently, approximately 5.84 gram of sodium chloride (merck 1.06404.0500) was added to the volumetric flasks of the 2, 4 and 8 mmol/L CuCl2 in
order to have a concentration of 0.1 M NaCl in the solution. The NaCl serves as a background electrolyte, which ensures that there is a defined ionic strength. The background electrolyte is important because the sorption capacity is determined by the ionic strength of the solution as it influences the solubility of other compounds.
First, the 2 mmol/L CuCl2 solution was prepared by pipetting 100 ml of the CuCl2 stock solution in a
1000 ml volumetric flask. Eventually the solution is diluted by adding Elga-water up to 1000 ml in the 1000 ml volumetric flask, ending up with a 2 mmol/L CuCl2 solution. Then, the 4 mmol/L CuCl2
solution was prepared by pipetting 200 ml of the CuCl2 stock solution in a 1000 ml volumetric flask.
The solution was diluted by adding Elga-water up to 1000 ml in the 1000 ml volumetric flask, ending up with a 4 mmol/L CuCl2 solution. Subsequently, the 8 mmol/L CuCl2 solution was prepared by
pipetting 400 ml of the CuCl2 stock solution in a 1000 ml volumetric flask. The solution was diluted by
adding Elga-water up to 1000 ml in the 1000 ml volumetric flask, ending up with a 8 mmol/L CuCl2
solution.
For the Zn solutions a stock solution of 20 mmol/L was prepared by first weighing 2,8389 gram of zinc chloride hydrate (Alfa Aesar 41247) continued by dissolving the ZnCl2 by adding Elga-water up to
1000 ml in a 1000 ml volumetric flask. Subsequently, approximately 5.84 gram of sodium chloride (merck 1.06404.0500) was added to the volumetric flasks of the 2, 4 and 8 mmol/L ZnCl2 in order to
have a concentration of 0.1 M NaCl in the solution. First, the 2 mmol/L ZnCl2 solution was prepared
by pipetting 100 ml of the ZnCl2 stock solution in a 1000 ml volumetric flask. The solution was diluted
by adding Elga-water up to 1000 ml in the 1000 ml volumetric flask, ending up with a 2 mmol/L ZnCl2
solution. Then, the 4 mmol/L ZnCl2 solution was prepared by pipetting 200 ml of the ZnCl2 stock
solution in a 1000 ml volumetric flask. The solution was diluted by adding Elga-water up to 1000 ml in the 1000 ml volumetric flask, ending up with a 4 mmol/L ZnCl2 solution. Subsequently, the 8 mmol/L
ZnCl2 solution was prepared by pipetting 400 ml of the ZnCl2 stock solution in a 1000 ml volumetric
flask. The solution was diluted by adding Elga-water up to 1000 ml in the 1000 ml volumetric flask, ending up with a 8 mmol/L ZnCl2 solution.
The multi-element solutions consist of Cu and Zn. This was done in order to delineate competition effects. The 2 mmol/L multi-element solution was prepared by pipetting 10 ml of both the 4 mmol/L
8 CuCl2 solution and the 4 mmol/L ZnCl2 solution directly into the 50 ml sample bottle. The 4 mmol/L
multi-element solution was prepared alike by pipetting the 8 mmol/L solutions instead. The 8 mmol/L multi-element solution was prepared by pipetting 200 ml of both stock solutions into a 500 ml volumetric flask. Subsequently, adding 2,9 gram of NaCl. Eventually, the solution was diluted by adding Elga-water up to 500 ml in the 500 ml volumetric flask.
2.2 Preparing the dissolved organic matter solution
For the dissolved organic matter solution, 10 gram of Aldrich Humic Acid (Aldrich H 1,675-2 Humic acid sodium salt) was weighed and diluted in 800 ml Elga-water and eventually filled up to 1000 ml. The Total organic carbon (TOC) was measured with the high temperature combustion TOC (type TOV-VCPH). The TOC value of the Humic acid solution was approximately 2800 mg/L C. For the
experiments the samples had to contain approximately 100 mg/L C, therefore the Aldrich Humic acid solution was diluted 10 times. In order to dilute the Aldrich Humic acid the solution had first to be centrifuged at 13.000 rpm and filtered over a RC55 membrane filter 0,45µm, since the solution was too turbid for filtration later on in the experiments. Eventually, an Aldrich Humic acid solution of approximately 280 mg/L in a 2000 ml volumetric flask was obtained. For the sample preparation 20 ml was pipetted in the 50 ml sample bottles that will contain dissolved organic matter (DOM), the concentration in these samples had been approximately 140 mg/L C.
2.3 Sample preparation
For the sample preparation there were 124 plastic sample bottles of 50 ml collected and these were properly labelled. For this sorption experiment brown and black biochar were chosen, the brown is low pyrolytic and the black is higher pyrolytic biochar. The expected adsorption capacity is higher for high pyrolytic biochar because of the bigger surface area and higher porosity (Chen, X et al. 2011). Subsequently, the brown and black biochar were first sieved with a grain size between 0.5 mm – 1 mm until 26 gram was obtained of both biochar. The experiment contained 4 samples without biochar. Furthermore, 60 sample bottles were each filled with 0,400 gram of black biochar and the other 60 sample bottles were each filled with 0,400 gram of black biochar. The experiments were done in triplicate in order to disable coincidence. Each series of the triplicate contained 36 samples, of which 18 with black biochar and 18 with brown biochar. In each sample 20 ml of the 2, 4 or 8 mmol/L Cu or Zn single element solution or the multi element solution was pipetted. Also, in each sample 20 ml of Elga- water for the clear sample or the dissolved organic matter solution was pipetted, this was done to be able to indicate the influence of DOM on the sorption process. Thus, because of dilution the concentrations of the single- and multi-element solutions in the samples were 1, 2 and 4 mmol/L, which is a natural concentration range (Trakal et al., 2011). If the sample contained DOM this concentration was approximately 140 mg/L C, due to dilution. Furthermore, each biochar had blanks without the element solutions but with or without the DOM solutions. And there were blanks without the biochar but with the DOM and with and without the 4 mmol/L multi element solution (Table 1). The blanks were used in order to correct the calibration level if that was necessary. Once all the samples were prepared they were shaken at 130 rpm for 48 hours to reach equilibrium (Qiu,Y., et al, 2008; Mohan, D ., et al, 2007). Furthermore, the study was performed at room temperature to be representative of environmentally relevant condition (Desta, M, B, 2013). Also, the pH of the solutions with brown biochar was 3,92 with a standard deviation of 0,35 and for black biochar the pH of the solutions was 7,48 with a standard deviation of 0,21.
9
Item Requisite Amount
Biochar Black and Brown biochar 2
Concentrations 1, 2 and 4 mmol/L 3
Solutions Cu/Zn Single- and multi- element 3
DOM/Clear Aldrich Humic Acid/Clear 2
Reps Total Blanks biochar Blanks Total samples Triplicate 2*2*3*3*3 =
Black and Brown, DOM/Clear, triplicate DOM, Clear / 4 mmol/L multi element solution 3 108 12 4 124 Table 1 2.4 Sample analysis
Once the samples had reached equilibrium, the samples were filtered with a filtration device over a Me 24 membrane filter 0,2µm. This was done in order to part the organic material and biochar that contained the adsorbed amount of solution with the equilibrium concentration. The filtered
equilibrium concentration solution was measured with the ICP. The ICP measured the metal concentration that was present in the equilibrium concentration. Once the measurements were done, the adsorbed concentration on the biochar was calculated and the equilibrium concentration was measured for TOC. The TOC measurements were done to indicate what amount of TOC was present in the equilibrium concentration, since it could have been precipitated with the metals or taken up by the biochar.
2.5 Adsorption isotherm
A common nonmechanistic technique used to determine substance adsorption is the adsorption isotherm. An adsorption isotherm is a graph of the equilibrium surface amount of a compound adsorbed (mmol/kg or mg/kg) which is called q, plotted against the equilibrium solution
concentration of the compound (mmol/L or mg/L) which is called Ce, at fixed pressure, temperature and solution chemistry (ionic strength) (Essington, M.E., 2004). The objective of performing an adsorption isotherm study is to obtain compound-specific adsorption parameters that quantitatively describe adsorption in a specific environment (Essington, M.E., 2004). The adsorption parameters that will be obtained are qm, which is the maximum amount that can be adsorbed before all adsorption places are filled and Kl which is an equilibrium constant which indicates how strong the affinity of the adsorbed compound to the sorbent is (Essington, M.E., 2004). The three most commonly used isotherm equations are the Langmuir equation, the Freundlich equation and the linear partition model (figure 1). For this
adsorption experiment the linear Langmuir isotherm is used, since the qm and Kl can be derived from the equation. However, according Essington, M.E., (2004) the Langmuir has some assumptions that should be met:
Adsorption occurs at specific sites on a surface.
All adsorption sites are identical in character.
10
A monolayer of adsorbed molecules is formed on the surface and an adsorption maximum is achieved as the monolayer becomes filled by the adsorbate.
The heat or energy of adsorption is constant over the entire surface.
Adsorbed species do not interact.
The volume of the monolayer and the energy of adsorption are independent of temperature.
Equilibrium is attained.
Once these assumptions were met the Langmuir equation could be used (Essington, M.E., 2004): qe = (qm *Kl*Ce) /(1+Kl*Ce)
This equation can be written as a linear Langmuir equation as followed (Essington, M.E., 2004): Ce/qe = 1/qm *Ce + 1/(Kl*qm)
This is equivalent to y=ax + b, where a = 1/qm and b = 1/(Kl*qm). With this equation the Ce/qe was placed on y-axis and Ce on the x-axis. The linear trend line with the equation was plotted through the data in Excel. The values for a and b were obtained from the equation and the values for qm and Kl were calculated.
11
3 Results
The aim in this research is to determine the sorption of heavy metals to Biochar and the potential effects of natural organic matter on this process. In order to elucidate this process the results will indicate four different situations. The first situation is the sorption of the single element solutions of Cu and Zn to brown biochar in a clear solution and in a solution with DOM. The second situation is the sorption of the single element solutions of Cu and Zn to black biochar in a clear solution and in a solution with DOM. The third situation is the sorption of the multi-element solutions of Cu and Zn to black biochar in a clear solution and in a solution with DOM. The fourth situation is the sorption of the multi-element solutions of Cu and Zn to brown biochar in a clear solution and in a solution with DOM. For each situation three graphs were plotted. One graph in which a logarithmic fit was plotted with the adsorbed concentration on the y-axis and the equilibrium concentration on the x-axis in order to visualize the sorption differences between Cu and Zn with and without DOM. Furthermore, a graph in which the linear Langmuir was plotted for Cu with Ce/q on the y-axis and Ce on the x-axis, the same graph was also plotted for Zn. Moreover, the logarithmic fits are qualitative and the linear fits are quantitative. Therefore, when both fits indicate different results, the results of the linear fit were used.
3.1 Brown biochar single element
By having the ICP analysed the equilibrium concentrations, the following linear Langmuir graphs for brown biochar were plotted (figure 2,3 ). With these graphs the qm and Kl were able to be derived from the equation.
Figure 2 y = 0.0438x - 1.3723 y = 0.2027x - 12.11 -20 0 20 40 60 80 100 0.000 50.000 100.000 150.000 200.000 250.000 300.000 Ce /q Ce
12 Figure 3
solution Langmuir equation qm (mg/kg) Kl
Cu DOM y = 0,0071x + 0,2844 140,84 0,024
Cu clear y = 0,0114x + 0,2303 8,77 0,495
Zn DOM y = 0,0438x - 1,3723 22,83 0,031
Zn clear y = 0,2027x - 12,11 4,93 0,016
Table 2 ( brown)
In table 2 it becomes clear that Cu with DOM has the highest adsorption maximum (qm) for brown biochar, which is a lot higher than the other adsorption maximums. Zn in a clear solution has the lowest qm for brown biochar. The strongest affinity (Kl) for brown biochar is for Cu in a clear solution, the weakest affinity is for Zn in a clear solution.
Figure 4 y = 0.0114x + 0.2303 0 0.5 1 1.5 2 2.5 3 3.5 0.000 50.000 100.000 150.000 200.000 250.000 Ce /q Ce
Cu with DOM Cu Clear
0 20 40 60 80 100 120 140 0 50 100 150 200 250 300 S orbed conc . (m g/ kg) Equilibrium Conc. (mg/L)
Observed Cu with DOM Observed Zn with DOM
Observed Zn Clear Observed Cu Clear
Log. (Observed Cu with DOM) Log. (Observed Zn with DOM)
Log. (Observed Zn Clear) Log. (Observed Cu Clear)
Sorption Cu/Zn to Brown biochar , clear and DOM
13 In figure 4 the highest adsorbed concentrations are for Cu with DOM and Cu in a clear solution. They tend to increase once there is a higher concentration of metals in contrast to the Zn of which the adsorbed concentration of the clear solutions is decreasing when there is a higher concentration of metals present in the solution. These trend lines correspond partly with the values in table 2, since the trendline for Cu clear, Zn clear and Zn DOM indicate a much higher adsorbed concentration than the qm values in table 2.
3.2 Black biochar single element
By having the ICP analysed the equilibrium concentrations, the following linear Langmuir graphs for black biochar were plotted (figure 5, 6). With these graphs the qm and Kl were able to be derived from the equation.
Figure 5 Figure 6 y = 0.006x + 0.0362 y = 0.0068x - 0.0183 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 0.000 20.000 40.000 60.000 80.000 100.000 120.000 140.000 160.000 Ce /q Ce
Zn with DOM Zn clear Linear (Zn with DOM) Linear (Zn with DOM)
y = 0.0019x + 0.0686 y = 0.0036x + 0.0142 0 0.05 0.1 0.15 0.2 0.25 0.000 5.000 10.000 15.000 20.000 25.000 30.000 Ce /q Ce
14
solution Langmuir equation qm (mg/kg) Kl
Cu DOM y = 0,0019x + 0,0686 526,31 0,276
Cu clear y = 0,0036x + 0,0142 277,78 0,253
Zn DOM y = 0,006x + 0,0362 166,67 0,165
Zn clear y = 0,0068x - 0,0183 147,05 0,371
Table 3 (black )
In table 3 it becomes clear that Cu with DOM has the highest adsorption maximum (qm) for brown biochar, which is a lot higher than the other adsorption maximums. Zn in a clear solution has the lowest qm for brown biochar. The strongest affinity (Kl) for brown biochar is for Zn in a clear solution, the weakest affinity is for Zn with DOM. The affinity for Cu with DOM and in a clear solution is close, but is slightly higher for Cu with DOM.
Figure 7
In figure 7 it is clear that the highest adsorbed concentrations are for Cu in a clear solution and Cu with DOM. The lowest adsorbed concentrations are for Zn. These trend lines correspond with the values found in table 3.
0 50 100 150 200 250 300 0 20 40 60 80 100 120 140 160 S orbed conc . (m g/ kg) Equilibrium Conc. (mg/L)
Observed Cu with DOM Observed Zn with DOM
Observed Zn Clear Observed Cu Clear
Log. (Observed Cu with DOM) Log. (Observed Zn with DOM) Log. (Observed Zn Clear) Log. (Observed Cu Clear)
15
3.3 Black competition
By having the ICP analysed the equilibrium concentrations, the following linear Langmuir graphs for black biochar with multi element solutions were plotted (figure 8, 9 ). With these graphs the qm and Kl were able to be derived from the equation.
Figure 8 Figure 9 y = 0.0275x + 0.1676 y = 0.0399x - 0.5167 -2 0 2 4 6 8 10 12 0.000 50.000 100.000 150.000 200.000 250.000 300.000 Ce /q Ce
Zn with DOM Zn clear Linear (Zn with DOM) Linear (Zn clear)
y = 0.0031x + 0.009 y = 0.0034x + 0.0051 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.000 1.000 2.000 3.000 4.000 5.000 6.000 7.000 8.000 9.000 Ce /q Ce
16
solution Langmuir equation qm (mg/L) Kl
Cu DOM y = 0,0031x + 0,009 322,58 0,344
Cu clear y = 0,0034x + 0,0051 294,11 0,666
Zn DOM y = 0,0275x + 0,1676 36,36 0,164
Zn clear y = 0,0399x - 0,5167 25,06 0,077
Table 4 ( black comp. )
In table 4 it becomes clear that Cu with DOM has the highest adsorption maximum (qm) for black biochar. Since Cu and Zn are both in the solution it also becomes clear that in a solution with DOM and in a clear solution the adsorption maximum is higher for Cu than for Zn. The affinity for Cu is higher as well.
Figure 10
The trendlines in figure 10 correspond with the findings in table 4. Since the adsorbed concentration for Cu is higher than for Zn.
0 50 100 150 200 250 300 0 50 100 150 200 250 300 S orbed conc . (m g/ kg) Equilibrium Conc. (mg/L)
Observed Cu with DOM Observed Zn with DOM
Observed Zn Clear Observed Cu Clear
Log. (Observed Cu with DOM) Log. (Observed Zn with DOM) Log. (Observed Zn Clear) Log. (Observed Cu Clear)
17
3. 4 Brown competition
By having the ICP analysed the equilibrium concentrations, the following linear Langmuir graphs for black biochar with multi element solutions were plotted (figure 11, 12 ). With these graphs the qm and Kl were able to be derived from the equation.
Figure 11 Figure 12 y = 0.5296x + 5.1766 y = 0.113x + 2.2458 0 20 40 60 80 100 120 140 160 180 200 0.000 50.000 100.000 150.000 200.000 250.000 300.000 Ce /q Ce
Zn with DOM Zn clear Linear (Zn with DOM) Linear (Zn clear)
y = 0.0084x + 0.2588 y = 0.01x + 0.3678 0 0.5 1 1.5 2 2.5 0.000 20.000 40.000 60.000 80.000 100.000 120.000 140.000 160.000 180.000 Ce /q Ce
18
solution Langmuir equation qm (mg/L) Kl
Cu DOM y = 0,0084x + 0,2588 119,04 0,032
Cu clear y = 0,01x + 0,3678 100,00 0,027
Zn DOM y = 0,5296x + 5,1766 1,88 0,102
Zn clear y = 0,113x + 2,2458 8,84 0,050
Table 5 (brown comp.)
In table 5 it becomes clear that Cu with DOM has the highest adsorption maximum (qm) for brown biochar. Since Cu and Zn are both in the solution it also becomes clear that in a solution with DOM and in a clear solution the adsorption maximum is higher for Cu than for Zn. In contrast to black biochar the affinity for Zn is higher than for Cu in a clear solution and with DOM.
Figure 13
The trendlines in figure 13 correspond with the values found in table 5, since the highest adsorbed concentrations are for Cu and the lowest adsorbed concentrations are for Zn.
-100 -50 0 50 100 150 200 250 300 0 50 100 150 200 250 300 S orbed conc . (m g/ kg) Equilibrium Conc. (mg/L)
Observed Cu with DOM Observed Zn with DOM
Observed Zn Clear Observed Cu Clear
Log. (Observed Cu with DOM) Log. (Observed Zn with DOM) Log. (Observed Zn Clear) Log. (Observed Cu Clear)
19
3.5 TOC
After the ICP analyses the total organic carbon (TOC) content of each sample that contained DOM was measured. The TOC findings are indicated in figure 14 and table 6.
Figure 14
Brown
Cu Brown Zn
Brown
Mix Black Cu Black Zn Black Mix
1 mmol - triplicate 1 98,1 127,6 77,5 61,8 59,6 11,9 2 mmol - triplicate 1 73,0 89,5 80,6 25,8 12,2 6,5 4 mmol - triplicate 1 80,5 80,7 82,5 7,2 6,5 5,2 1 mmol - triplicate 2 86,1 124,8 84,2 67,1 51,8 8,5 2 mmol - triplicate 2 76,1 87,1 69,7 7,1 9,5 5,1 4 mmol - triplicate 2 80,6 84,0 80,6 4,6 6,6 4,3 1 mmol - triplicate 3 84,2 116,6 75,3 - 22,8 6,0 2 mmol - triplicate 3 76,4 87,0 74,0 5,3 8,1 4,1 4 mmol - triplicate 3 73,2 77,1 69,9 4,2 6,0 3,3 Table 6
In figure 14 and table 6 it becomes clear that the brown biochar has a much higher TOC content than the black carbon. Furthermore, for both biochar the TOC content is lowest for the multi element solutions (Mix).
In figure 15 and table 7, the blanks are indicated. There are series of blanks that contained black or brown biochar without a metal solution (black blank, brown blank). There were blanks with the 4 mmol/L multi element solutions but without biochar (blank mix). Furthermore, there were blanks without biochar as well as a metal solution (blank blank).
0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 Brown Cu Brown Zn Brown Mix
Black CuBlack Zn Black Mix 1 mmol - triplicate 1 2 mmol - triplicate 1 4 mmol - triplicate 1 1 mmol - triplicate 2 2 mmol - triplicate 2 4 mmol - triplicate 2 1 mmol - triplicate 3 2 mmol - triplicate 3 4 mmol - triplicate 3
20 Figure 15
Black Blank Brown Blank Blank Blank Blank Mix
triplicate 1 65,3 132,3 98,1 5,8
triplicate 2 60,1 131,9 92,8 8,3
triplicate 3 69,0 135,1
Table 7
In figure 15 and table 7 it becomes clear that the blank with the Brown biochar has a higher TOC content than the black biochar. This indicates that the black biochar has a higher adsorption capacity for TOC than the brown biochar. Also, the blank with the multi element solution but without biochar has the lowest TOC content and this indicates that it possible that a lot of TOC is precipitated with the metals. 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0
Black Blank Brown Blank Blank Blank Blank Mix
triplicate 1 triplicate 2 triplicate 3
21
4 Discussion
During the lab experiments working accurately is very important in order to generate reliable results. However, the accuracy depends on multiple factors. Factors that have or could have influenced the results will be discussed below.
4.1 Biochar
For this sorption experiment black and brown biochar were used. Although it was known which one was high and which one was low pyrolytic, it has failed to find more information about the origin of the used biochar. It could have been interesting to know more about the used biochar.
4.2 Solutions
For the preparation of the 20 mmol/L stock solutions zinc chloride hydrate and copper(ll)chloride-dihydrate was used. Since zinc chloride hydrate contained an unknown amount of crystal water, it was difficult to prepare a stock solution that would contain 20 mmol/L of Zn. Eventually after ICP measurements the Zn stock solution contained 22 mmol/L. The Cu stock solutions contained 21 mmol/L. Since the stock solutions were used to prepare the solutions with lower concentrations, these solutions also contained a slightly higher concentration than 2, 4 and 8 mmol/L.
4.3 Pipetting
The solutions with lower concentrations of Cu and Zn were prepared by pipetting a certain amount of solution from the stock. The concentration in the solutions with lower concentrations could have been influenced by the pipet due to possible calibration errors. Furthermore, when pipetting the concentrated solutions in the samples a manual pipet was used first, and later on an automatic pipet was used. The two different types of pipets could have a slightly difference in calibration, which could have influenced the concentration pipetted in the samples.
4.4 Loss of samples
During the experiments sample 20 and 82 (Appendix A) were lost, but since the experiments were done in triplicate it had no major consequences. Furthermore, the samples 54 and 72 (Appendix A) for the sorption of the multi element solution to black biochar indicated after ICP analysis an equilibrium concentration for Zn that was higher than the initial concentration of Zn, which would indicate a negative adsorbed concentration. For the samples 63 and 98 for the sorption of the multi element solution to brown biochar the same event occurred for Zn. This could be possible due to a measurement error in the ICP analysis, or because of contamination during pipetting. These samples were not included in the results. This will not have a major influence on the results, since the
experiment were done in triplicate.
4.5 Controlling pH
The pH of the samples with brown biochar was 3,92 with std 0,35, the pH of the samples with black biochar was 7,48 with a std of 0,21. Initially, the pH of the samples of both biochar was supposed to be controlled at the same pH, but because of the order in the steps of the method this was not possible anymore. It was supposed to control the pH of the samples when the samples were prepared, but when the measurer was set in the sample, the biochar would stick to the
pH-22 measurer. This would cause the amount of biochar to decline and would influence the adsorption capacity of each sample. Therefore, there has been chosen not to bring the samples at a certain pH, and measure the pH afterwards. Therefore, the research question which biochar has the highest sorption capacity, is actually not allowed to answer anymore, since the samples of both biochar are at a different pH.
4.6 Adsorption isotherm
For this sorption experiment there has been chosen for the Langmuir adsorption isotherm. Since, it was not possible with excel to plot multiple fitting lines of the non-linear Langmuir in one graph, the choice was made to use the linear form of the Langmuir adsorption isotherm. It is possible that the linear Langmuir isotherm would indicate different values for the parameters qm and Kl than the non-linear Langmuir isotherm.
4.7 The parameters qm and Kl
Overall the adsorption maximum (qm) indicated the same trend for each of the four situations. Where Cu with DOM has the highest sorption capacity respectively followed by Cu in a clear solution, Zn with DOM and Zn in a clear solution. There are two deviations to this trend, in the sorption of the single element solutions to brown biochar, the adsorption maximum for Cu in a clear solution is lower than for Zn with DOM. The second deviation is in the sorption of the multi element solutions to brown biochar where the adsorption maximum for Zn with DOM is lower than for Zn in a clear solution. The affinity indicated that overall the affinity for Cu to biochar was higher than for Zn. Although, this was not the same for every situation. Both deviations could be caused by the limited amount of data points that were used for the Langmuir adsorption isotherm, since the linear line could be influenced by outliers.
4.8 results
The result from the sorption experiment indicated that of the two forms of biochar used in this experiment, the black biochar has the highest sorption capacity. Although, it is actually not allowed to make this comparison because of the difference in pH. But, when the tables 2-5 are compared it is still very clear that the black biochar has the highest sorption capacity. This was also expected, because the black biochar was higher pyrolytic than the brown biochar. Therefore, the black biochar has a bigger surface area and a higher porosity which in turn leads to more adsorption sites and a higher sorption capacity. this is consistent with the findings of Chen, X et al. (2011) that indicated that the high pyrolytic CS600 biochar had a higher sorption capacity than the lower pyrolytic HW450 biochar.
Furthermore, there are clear differences in effects of biochar in a clear solution compared to biochar with DOM. The biochar in a solution with DOM has a higher adsorption maximum and stronger affinity than in a clear solution. This difference can be caused by the fact that the DOM precipitates with the metals, which influences the concentration that is seen as adsorbed. Therefore, it could indicate a higher adsorption maximum for a solution with DOM than in a clear solution. But according Uchima, M., et al, (2010) biochar has two mechanisms to bind organic material, via the surface adsorption on carbonized fractions and the partitioning mechanism. The partitioning mechanism is used at low pyrolytic temperatures, but since the pyrolytic temperatures of the used
23 biochar are unknown, it is not possible to determine which mechanism is used for the binding of organic material to biochar. But, since biochar can adsorb organic material, another possibility is that the DOM binds to the biochar and the metals are able to bind to the DOM. Therefore, there are no adsorption sites lost and the adsorption capacity of biochar would not be negatively influenced by DOM.
The experiments indicated that the bioavailability of the metals Cu and Zn are lower in the presence of dissolved organic matter. This result can be unreliable since Cu and Zn could also bind to the DOM and precipitate, which does not lower the bioavailability of the metals. Furthermore, if it is the case that the bioavailability would be lower in the presence of DOM, the bioavailability of Cu is influenced the most. Because for each situation the adsorption maximum is higher for Cu than for Zn and the affinity is stronger for Cu than for Zn. These findings are consistent with the findings of Chen, X et al., (2011) since their findings also indicate a higher adsorption maximum and a stronger affinity for Cu than for Zn (Table 8).
Since Cu and Zn often coexist in the environment, their competitive adsorption characteristics in multi element solutions were also investigated (table 4-5). The data clearly show that in the presence of Zn, the adsorption of Cu to black and brown biochar is higher in a clear solution as well as in a solution of DOM. These results clearly suggest that Cu can compete with Zn for binding sites. This competition is likely due to the higher affinity of the biochars for Cu than Zn, and can be caused by the fact that Cu can bind to the carboxyl groups of the biochars. These findings are consistent with the findings of Chen, X., et al. (2011), that also indicated that in the presence of Zn the adsorption for Cu is higher. biochar metals qm Kl CS600 Cu 12.52 0.682 CS600 Zn 11.00 0.232 HW450 Cu 6.79 0.048 HW450 Zn 4.54 0.061 Table 8
24
5 Conclusions
During this research the sorption of Cu and Zn to two forms of biochar made at different temperatures and the potential effects of natural organic matter on this process has been researched. This is done by performing a batch sorption experiment.
The result from the sorption experiment indicated that of the two forms of biochar used in this experiment, the black biochar has the highest sorption capacity. Although, it is actually not allowed to make this comparison because of the difference in pH as described in the discussion. Furthermore, there are clear differences in effects of biochar in a clear solution compared to biochar with DOM. The biochar in a solution with DOM has a higher adsorption maximum and stronger affinity than in a clear solution. But it cannot be concluded that the higher adsorption maximum is caused by the precipitation of DOM with the metals Cu and Zn, or by the binding of DOM to biochar in which the biochar does not lose any adsorption sites. Also, the bioavailability of the metals Cu and Zn are lower in the presence of dissolved organic matter. But, as discussed in the discussion this result can be unreliable since Cu and Zn could also bind to the DOM and precipitate, which does not lower the bioavailability of the metals. But it can be concluded that if it is the case that the bioavailability would be lower in the presence of DOM, the bioavailability of Cu is influenced the most. Furthermore, it can be concluded that in the multi element solutions for the competition effects, the adsorption of Cu to black and brown biochar is higher in a clear solution as well as in a solution of DOM.
In order to conclude, based on this experiment it is clear that dissolved organic matter has an effect on the sorption of Cu and Zn to the black and brown biochar. But, it is not possible to determine the precise influence of dissolved organic matter on this process.
Due to several measurement errors and other uncertainties as described in the discussion, the results are not completely reliable. Therefore, for further research these errors should be taken into account.
25
6 References
Beesley, L., E. Moreno-Jiménez, and J. L. Gomez-Eyles. 2010. Effects of biochar and greenwaste compost amendments on mobility, bioavailability and toxicity of inorganic and organic contaminants in a multi-element polluted soil. Environ.Pollut. 158:2282-2287.
Beesley, L., E. Moreno-Jiménez, J. L. Gomez-Eyles, E. Harris, B. Robinson, and T. Sizmur. 2011. A review of biochars' potential role in the remediation, revegetation and restoration of contaminated soils. Environ.Pollut. 159:3269-3282.
Cao, X.D., Ma, L.N., Gao, B., Harris, W., 2009. Dairy-manure derived biochar effectively sorbs lead and atrazine. Environmental Science and Technology. 43: 3285-3291.
Desta, M, B. 2013. Batch Sorption Experiments: Langmuir and Freundlich Isotherm Studies for the Adsorption of Textile Metal Ions onto Teff Straw (Eragrostis tef ) Agricultural Waste. Journal of Thermodynamics. http://dx.doi.org/10.1155/2013/375830
Essington, M.E., 2004 Soil and water chemistry : an integrative approach,CRC Press, pp. 338-343
Inyang, M., Gao, B., Yao, Y., Xue, Y., Zimmerman, A, R., Pullammanappallil, P., and Cao, X. 2012. Removal of heavy metals from aqueous solution by biochars derived from anaerobically digested biomass. Bioresource Technology 110: 50–56
Mohan,D., Pittman Jr, C,U., Bricka, M., Smith, F., Yancey, B., Mohammed, J., Steele, P,H., Alexandre-Franco, M,F., Gómez-Serrano, V, and Gong, H. 2007. Sorption of arsenic, cadmium, and lead by chars produced from fast pyrolysis of wood and bark during bio-oil production. Journal of Colloid and Interface Science. 310: 57-73.
Qiu, Y., Cheng, H., Xu, C., and Sheng, G, D. 2008. Surface characteristics of crop-residue-derived black carbon and lead(II) adsorption. Water research. 42: 567-574
Trakal, L., M. Komárek, J. Száková, V. Zemanová, and P. Tlustos. 2011. Biochar application to metal-contaminated soil: evaluating of Cd, Cu, Pb and Zn sorption behavior using single- and multi-element sorption experiment. Plant Soil Environ. 57:372-380.
Uchimiya, M., Lima, I, M., Klasson, K, T., Chang, S., Wartelle, L, H, and Rodgers, J, M. 2010. Immobilization of Heavy Metal Ions (CuII, CdII, NiII, and PbII) by Broiler Litter-Derived Biochars in Water and Soil. J. Agric. Food Chem. 58: 5538–5544
Yang, G.-X.; Jiang, H., Amino modification of biochar for enhanced adsorption of copper ions from synthetic wastewater. Wat.Res. 2014, 48, 396-405.
26
7 Appendix Appendix A
Biochar-Metal-Concentration-Organic-RepetitionNummer Biochar weight biocharMetal ConcentrationDOM Repitition volume * verloren samples (rood)
Sample Id (mg/L)Zn (mg/L)Cu (µmol/L)Zn (µmol/L)Cu Initial amount Zn/Cu (mg/L) Initial amount Cu (mg/L) Sorbed amount Zn/Cu (mg/L) Sorbed amount Cu (mg/L) pH TOC
BR-CU-1-DOM-1 1 Brown 0,4 gram Cu 1 mmol DOM 1 40 ml 2015/MB/1 1,187 20,956 18,16 329,80 59,229 38,273 4,18 98,1 BR-CU-2-DOM-1 2 Brown 0,4 gram Cu 2 mmol DOM 1 40 ml 2015/MB/2 1,113 39,426 17,03 620,49 120,909 81,483 4,05 73,0 BR-CU-4-DOM-1 3 Brown 0,4 gram Cu 4 mmol DOM 1 40 ml 2015/MB/3 1,547 136,004 23,67 2140,45 255,232 119,228 3,57 80,5 BR-CU-1-DOM-2 37 Brown 0,4 gram Cu 1 mmol DOM 2 40 ml 2015/MB/37 0,740 17,114 11,32 269,34 59,229 42,115 4,32 86,1 BR-CU-2-DOM-2 38 Brown 0,4 gram Cu 2 mmol DOM 2 40 ml 2015/MB/38 4,388 43,636 67,12 686,74 120,909 77,273 3,9 76,1 BR-CU-4-DOM-2 39 Brown 0,4 gram Cu 4 mmol DOM 2 40 ml 2015/MB/39 22,432 128,824 343,15 2027,45 255,232 126,408 80,6 BR-CU-1-DOM-3 73 Brown 0,4 gram Cu 1 mmol DOM 3 40 ml 2015/MB/73 1,215 18,264 18,58 287,44 59,229 40,965 84,2 BR-CU-2-DOM-3 74 Brown 0,4 gram Cu 2 mmol DOM 3 40 ml 2015/MB/74 3,218 46,172 49,22 726,65 120,909 74,737 76,4 BR-CU-4-DOM-3 75 Brown 0,4 gram Cu 4 mmol DOM 3 40 ml 2015/MB/75 23,065 159,290 352,84 2506,92 255,232 95,942 73,2 BR-Zn-1-DOM-1 4 Brown 0,4 gram Zn 1 mmol DOM 1 40 ml 2015/MB/4 32,389 0,644 495,48 10,13 67,398 35,009 4,54 127,6 BR-Zn-2-DOM-1 5 Brown 0,4 gram Zn 2 mmol DOM 1 40 ml 2015/MB/5 79,833 2,280 1221,24 35,88 128,959 49,126 4,36 89,5 BR-Zn-4-DOM-1 6 Brown 0,4 gram Zn 4 mmol DOM 1 40 ml 2015/MB/6 203,308 18,507 3110,11 291,27 278,261 74,953 4,08 80,7 BR-Zn-1-DOM-2 40 Brown 0,4 gram Zn 1 mmol DOM 2 40 ml 2015/MB/40 34,363 0,642 525,67 10,11 67,398 33,035 124,8 BR-Zn-2-DOM-2 41 Brown 0,4 gram Zn 2 mmol DOM 2 40 ml 2015/MB/41 85,273 3,429 1304,47 53,96 128,959 43,685 87,1 BR-Zn-4-DOM-2 42 Brown 0,4 gram Zn 4 mmol DOM 2 40 ml 2015/MB/42 232,423 17,108 3555,49 269,25 278,261 45,838 84,0 BR-Zn-1-DOM-3 76 Brown 0,4 gram Zn 1 mmol DOM 3 40 ml 2015/MB/76 39,437 0,914 603,28 14,38 67,398 27,962 116,6 BR-Zn-2-DOM-3 77 Brown 0,4 gram Zn 2 mmol DOM 3 40 ml 2015/MB/77 83,918 1,080 1283,73 17,00 128,959 45,041 87,0 BR-Zn-4-DOM-3 78 Brown 0,4 gram Zn 4 mmol DOM 3 40 ml 2015/MB/78 262,991 0,270 4023,12 4,26 278,261 15,27 77,1 BR-MIX-1-DOM-1 7 Brown 0,4 gram Mix 1 mmol DOM 1 40 ml 2015/MB/7 45,664 16,685 698,54 262,59 64,480 60,455 18,816 43,770 4,19 77,5 BR-MIX-2-DOM-1 8 Brown 0,4 gram Mix 2 mmol DOM 1 40 ml 2015/MB/8 118,607 48,459 1814,40 762,65 139,131 127,616 20,524 79,067 3,75 80,6 BR-MIX-4-DOM-1 9 Brown 0,4 gram Mix 4 mmol DOM 1 40 ml 2015/MB/9 268,806 138,207 4112,08 2175,12 279,022 249,210 10,216 111,003 3,49 82,5 BR-MIX-1-DOM-2 43 Brown 0,4 gram Mix 1 mmol DOM 2 40 ml 2015/MB/43 46,930 19,166 717,91 301,64 64,480 60,455 17,55 41,289 84,2 BR-MIX-2-DOM-2 44 Brown 0,4 gram Mix 2 mmol DOM 2 40 ml 2015/MB/44 115,579 48,232 1768,07 759,07 139,131 127,616 23,552 79,384 69,7 BR-MIX-4-DOM-2 45 Brown 0,4 gram Mix 4 mmol DOM 2 40 ml 2015/MB/45 277,470 143,911 4244,60 2264,89 279,022 249,210 1,552 105,299 80,6 BR-MIX-1-DOM-3 79 Brown 0,4 gram Mix 1 mmol DOM 3 40 ml 2015/MB/79 51,146 19,526 782,41 307,30 64,480 60,455 13,334 40,929 75,3 BR-MIX-2-DOM-3 80 Brown 0,4 gram Mix 2 mmol DOM 3 40 ml 2015/MB/80 138,780 56,070 2123,00 882,43 139,131 127,616 0,351 71,546 74,0 BR-MIX-4-DOM-3 81 Brown 0,4 gram Mix 4 mmol DOM 3 40 ml 2015/MB/81 20,140 161,527 308,10 2542,12 279,022 249,210 258,882 87,683 69,9 BL-CU-1-DOM-1 10 Black 0,4 gram Cu 1 mmol DOM 1 40 ml 2015/MB/10 1,233 5,186 18,87 81,61 59,229 54,043 7,73 61,8 BL-CU-2-DOM-1 11 Black 0,4 gram Cu 2 mmol DOM 1 40 ml 2015/MB/11 6,904 5,860 105,61 92,23 120,909 115,049 7,38 25,8 BL-CU-4-DOM-1 12 Black 0,4 gram Cu 4 mmol DOM 1 40 ml 2015/MB/12 32,928 20,753 503,72 326,61 255,232 234,479 7,24 7,2 BL-CU-1-DOM-2 46 Black 0,4 gram Cu 1 mmol DOM 2 40 ml 2015/MB/46 1,301 10,873 19,90 171,12 59,229 48,356 67,1 BL-CU-2-DOM-2 47 Black 0,4 gram Cu 2 mmol DOM 2 40 ml 2015/MB/47 8,478 5,195 129,69 81,76 120,909 115,714 7,1 BL-CU-4-DOM-2 48 Black 0,4 gram Cu 4 mmol DOM 2 40 ml 2015/MB/48 34,633 25,509 529,80 401,46 255,232 229,723 4,6
BL-CU-1-DOM-3 82 Black 0,4 gram Cu 1 mmol DOM 3 40 ml 59,229 59,229
BL-CU-2-DOM-3 83 Black 0,4 gram Cu 2 mmol DOM 3 40 ml 2015/MB/83 6,794 4,354 103,93 68,53 120,909 116,555 5,3 BL-CU-4-DOM-3 84 Black 0,4 gram Cu 4 mmol DOM 3 40 ml 2015/MB/84 3,366 19,232 51,49 302,68 255,232 235,999 4,2 BL-Zn-1-DOM-1 13 Black 0,4 gram Zn 1 mmol DOM 1 40 ml 2015/MB/13 4,147 0,190 63,44 2,99 67,398 63,251 7,78 59,6 BL-Zn-2-DOM-1 14 Black 0,4 gram Zn 2 mmol DOM 1 40 ml 2015/MB/14 11,103 0,349 169,84 5,49 128,959 117,856 7,48 12,2 BL-Zn-4-DOM-1 15 Black 0,4 gram Zn 4 mmol DOM 1 40 ml 2015/MB/15 44,487 2,881 680,54 45,34 278,261 223,774 7,45 6,5 BL-Zn-1-DOM-2 49 Black 0,4 gram Zn 1 mmol DOM 2 40 ml 2015/MB/49 8,264 0,390 126,42 6,14 67,398 59,134 51,8 BL-Zn-2-DOM-2 50 Black 0,4 gram Zn 2 mmol DOM 2 40 ml 2015/MB/50 14,205 0,324 217,31 5,09 128,959 114,753 9,5 BL-Zn-4-DOM-2 51 Black 0,4 gram Zn 4 mmol DOM 2 40 ml 2015/MB/51 126,262 0,128 1931,50 2,02 278,261 151,999 6,6 BL-Zn-1-DOM-3 85 Black 0,4 gram Zn 1 mmol DOM 3 40 ml 2015/MB/85 7,167 0,698 109,64 10,99 67,398 60,232 22,8 BL-Zn-2-DOM-3 86 Black 0,4 gram Zn 2 mmol DOM 3 40 ml 2015/MB/86 7,873 0,287 120,44 4,51 128,959 121,085 8,1 BL-Zn-4-DOM-3 87 Black 0,4 gram Zn 4 mmol DOM 3 40 ml 2015/MB/87 119,616 2,945 1829,83 46,35 278,261 158,645 6,0 BL-MIX-1-DOM-1 16 Black 0,4 gram Mix 1 mmol DOM 1 40 ml 2015/MB/16 6,383 1,027 97,65 16,16 64,480 60,455 58,097 59,428 7,67 11,9 BL-MIX-2-DOM-1 17 Black 0,4 gram Mix 2 mmol DOM 1 40 ml 2015/MB/17 75,093 0,634 1148,74 9,98 139,131 127,616 64,038 126,982 7,43 6,5 BL-MIX-4-DOM-1 18 Black 0,4 gram Mix 4 mmol DOM 1 40 ml 2015/MB/18 231,376 2,988 3539,49 47,02 279,022 249,210 47,646 246,222 7,130 5,2 BL-MIX-1-DOM-2 52 Black 0,4 gram Mix 1 mmol DOM 2 40 ml 2015/MB/52 4,622 0,382 70,70 6,02 64,480 60,455 59,858 60,073 8,5 BL-MIX-2-DOM-2 53 Black 0,4 gram Mix 2 mmol DOM 2 40 ml 2015/MB/53 98,630 2,013 1508,80 31,68 139,131 127,616 40,501 125,603 5,1 BL-MIX-4-DOM-2 54 Black 0,4 gram Mix 4 mmol DOM 2 40 ml 2015/MB/54 297,955 6,294 4557,98 99,06 279,022 249,210 0 242,916 4,3 BL-MIX-1-DOM-3 88 Black 0,4 gram Mix 1 mmol DOM 3 40 ml 2015/MB/88 21,843 0,970 334,15 15,26 64,480 60,455 42,637 59,485 6,0 BL-MIX-2-DOM-3 89 Black 0,4 gram Mix 2 mmol DOM 3 40 ml 2015/MB/89 123,311 3,215 1886,35 50,60 139,131 127,616 15,82 124,401 4,1 BL-MIX-4-DOM-3 90 Black 0,4 gram Mix 4 mmol DOM 3 40 ml 2015/MB/90 7,425 8,557 113,59 134,67 279,022 249,210 271,597 240,653 3,3 BR-CU-1-Clear-1 19 Brown 0,4 gram Cu 1 mmol Clear 1 40 ml 2015/MB/19 1,496 19,543 22,88 307,58 59,229 39,686 4,05
BR-CU-2-Clear-1 20 Brown 0,4 gram Cu 2 mmol Clear 1 40 ml 120,909 120,909 3,68
BR-CU-4-Clear-1 21 Brown 0,4 gram Cu 4 mmol Clear 1 40 ml 2015/MB/21 21,472 163,807 328,48 2578,01 255,232 91,425 3,37 BR-CU-1-Clear-2 55 Brown 0,4 gram Cu 1 mmol Clear 2 40 ml 2015/MB/55 0,966 20,562 14,78 323,60 59,229 38,667 BR-CU-2-Clear-2 56 Brown 0,4 gram Cu 2 mmol Clear 2 40 ml 2015/MB/56 3,974 58,152 60,80 915,20 120,909 62,757 BR-CU-4-Clear-2 57 Brown 0,4 gram Cu 4 mmol Clear 2 40 ml 2015/MB/57 23,309 161,265 356,57 2538,01 255,232 93,966 BR-CU-1-Clear-3 91 Brown 0,4 gram Cu 1 mmol Clear 3 40 ml 2015/MB/91 1,237 22,388 18,92 352,34 59,229 36,841 BR-CU-2-Clear-3 92 Brown 0,4 gram Cu 2 mmol Clear 3 40 ml 2015/MB/92 4,255 43,017 65,08 677,00 120,909 77,892 BR-CU-4-Clear-3 93 Brown 0,4 gram Cu 4 mmol Clear 3 40 ml 2015/MB/93 2,309 190,811 35,32 3003,01 255,232 64,421 BR-Zn-1-Clear-1 22 Brown 0,4 gram Zn 1 mmol Clear 1 40 ml 2015/MB/22 38,518 0,713 589,24 11,22 67,398 28,88 4,23 BR-Zn-2-Clear-1 23 Brown 0,4 gram Zn 2 mmol Clear 1 40 ml 2015/MB/23 99,097 0,089 1515,93 1,41 128,959 29,862 4,03 BR-Zn-4-Clear-1 24 Brown 0,4 gram Zn 4 mmol Clear 1 40 ml 2015/MB/24 238,764 17,903 3652,50 281,76 278,261 39,947 3,87 BR-Zn-1-Clear-2 58 Brown 0,4 gram Zn 1 mmol Clear 2 40 ml 2015/MB/58 40,044 0,595 612,58 9,36 67,398 27,354 BR-Zn-2-Clear-2 59 Brown 0,4 gram Zn 2 mmol Clear 2 40 ml 2015/MB/59 95,009 3,858 1453,41 60,72 128,959 33,949 BR-Zn-4-Clear-2 60 Brown 0,4 gram Zn 4 mmol Clear 2 40 ml 2015/MB/60 261,662 16,005 4002,78 251,89 278,261 16,599 BR-Zn-1-Clear-3 94 Brown 0,4 gram Zn 1 mmol Clear 3 40 ml 2015/MB/94 42,728 0,755 653,63 11,88 67,398 24,671 BR-Zn-2-Clear-3 95 Brown 0,4 gram Zn 2 mmol Clear 3 40 ml 2015/MB/95 108,814 3,259 1664,59 51,29 128,959 20,145 BR-Zn-4-Clear-3 96 Brown 0,4 gram Zn 4 mmol Clear 3 40 ml 2015/MB/96 275,408 18,112 4213,07 285,04 278,261 2,853 BR-MIX-1-Clear-1 25 Brown 0,4 gram Mix 1 mmol Clear 1 40 ml 2015/MB/25 52,707 20,358 806,29 320,40 64,480 60,455 11,773 40,097 3,92 BR-MIX-2-Clear-1 26 Brown 0,4 gram Mix 2 mmol Clear 1 40 ml 2015/MB/26 125,124 60,625 1914,09 954,13 139,131 127,616 14,007 66,991 3,52 BR-MIX-4-Clear-1 27 Brown 0,4 gram Mix 4 mmol Clear 1 40 ml 2015/MB/27 271,157 158,106 4148,03 2488,28 279,022 249,210 7,865 91,104 3,30 BR-MIX-1-Clear-2 61 Brown 0,4 gram Mix 1 mmol Clear 2 40 ml 2015/MB/61 53,105 23,042 812,38 362,63 64,480 60,455 11,375 37,413 BR-MIX-2-Clear-2 62 Brown 0,4 gram Mix 2 mmol Clear 2 40 ml 2015/MB/62 130,640 63,722 1998,48 1002,86 139,131 127,616 8,491 63,894 BR-MIX-4-Clear-2 63 Brown 0,4 gram Mix 4 mmol Clear 2 40 ml 2015/MB/63 293,581 170,863 4491,07 2689,06 279,022 249,210 0 78,347 BR-MIX-1-Clear-3 97 Brown 0,4 gram Mix 1 mmol Clear 3 40 ml 2015/MB/97 62,387 25,368 954,37 399,24 64,480 60,455 2,093 35,087 BR-MIX-2-Clear-3 98 Brown 0,4 gram Mix 2 mmol Clear 3 40 ml 2015/MB/98 157,836 65,370 2414,51 1028,80 139,131 127,616 0 62,246 BR-MIX-4-Clear-3 99 Brown 0,4 gram Mix 4 mmol Clear 3 40 ml 2015/MB/99 32,260 170,549 493,50 2684,12 279,022 249,210 246,762 78,661 BL-CU-1-Clear-1 28 Black 0,4 gram Cu 1 mmol Clear 1 40 ml 2015/MB/28 1,808 0,751 27,66 11,83 59,229 58,478 7,85 BL-CU-2-Clear-1 29 Black 0,4 gram Cu 2 mmol Clear 1 40 ml 2015/MB/29 8,169 4,185 124,96 65,86 120,909 116,724 7,66 BL-CU-4-Clear-1 30 Black 0,4 gram Cu 4 mmol Clear 1 40 ml 2015/MB/30 31,337 20,980 479,37 330,19 255,232 234,252 7,56 BL-CU-1-Clear-2 64 Black 0,4 gram Cu 1 mmol Clear 2 40 ml 2015/MB/64 1,545 0,675 23,63 10,62 59,229 58,554 BL-CU-2-Clear-2 65 Black 0,4 gram Cu 2 mmol Clear 2 40 ml 2015/MB/65 8,862 4,668 135,57 73,46 120,909 116,241 BL-CU-4-Clear-2 66 Black 0,4 gram Cu 4 mmol Clear 2 40 ml 2015/MB/66 29,715 19,498 454,56 306,85 255,232 235,734 BL-CU-1-Clear-3 100 Black 0,4 gram Cu 1 mmol Clear 3 40 ml 2015/MB/100 2,210 0,953 33,81 15,00 59,229 58,276 BL-CU-2-Clear-3 101 Black 0,4 gram Cu 2 mmol Clear 3 40 ml 2015/MB/101 7,757 4,132 118,67 65,04 120,909 116,776 BL-CU-4-Clear-3 102 Black 0,4 gram Cu 4 mmol Clear 3 40 ml 2015/MB/102 1,286 6,577 19,68 103,51 255,232 248,655 BL-Zn-1-Clear-1 31 Black 0,4 gram Zn 1 mmol Clear 1 40 ml 2015/MB/31 0,328 0,013 5,01 0,20 67,398 67,071 7,6 BL-Zn-2-Clear-1 32 Black 0,4 gram Zn 2 mmol Clear 1 40 ml 2015/MB/32 6,254 0,298 95,67 4,69 128,959 122,705 7,37 BL-Zn-4-Clear-1 33 Black 0,4 gram Zn 4 mmol Clear 1 40 ml 2015/MB/33 67,968 3,054 1039,74 48,06 278,261 210,293 7,31 BL-Zn-1-Clear-2 67 Black 0,4 gram Zn 1 mmol Clear 2 40 ml 2015/MB/67 0,186 0,035 2,84 0,55 67,398 67,213 BL-Zn-2-Clear-2 68 Black 0,4 gram Zn 2 mmol Clear 2 40 ml 2015/MB/68 2,910 0,268 44,52 4,22 128,959 126,048 BL-Zn-4-Clear-2 69 Black 0,4 gram Zn 4 mmol Clear 2 40 ml 2015/MB/69 51,255 3,058 784,07 48,12 278,261 227,006 BL-Zn-1-Clear-3 103 Black 0,4 gram Zn 1 mmol Clear 3 40 ml 2015/MB/103 0,647 0,026 9,89 0,42 67,398 66,752 BL-Zn-2-Clear-3 104 Black 0,4 gram Zn 2 mmol Clear 3 40 ml 2015/MB/104 2,854 3,335 43,65 52,49 128,959 126,105 BL-Zn-4-Clear-3 105 Black 0,4 gram Zn 4 mmol Clear 3 40 ml 2015/MB/105 142,358 0,792 2177,73 12,47 278,261 135,903 BL-MIX-1-Clear-1 34 Black 0,4 gram Mix 1 mmol Clear 1 40 ml 2015/MB/34 6,148 0,158 94,04 2,48 64,480 60,455 58,332 60,297 7,55 BL-MIX-2-Clear-1 35 Black 0,4 gram Mix 2 mmol Clear 1 40 ml 2015/MB/35 97,562 0,837 1492,47 13,18 139,131 127,616 41,569 126,779 7,25 BL-MIX-4-Clear-1 36 Black 0,4 gram Mix 4 mmol Clear 1 40 ml 2015/MB/36 253,406 2,751 3876,49 43,30 279,022 249,210 25,616 246,459 7,19 BL-MIX-1-Clear-2 70 Black 0,4 gram Mix 1 mmol Clear 2 40 ml 2015/MB/70 32,415 0,702 495,87 11,05 64,480 60,455 32,065 59,753 BL-MIX-2-Clear-2 71 Black 0,4 gram Mix 2 mmol Clear 2 40 ml 2015/MB/71 86,789 0,600 1327,65 9,45 139,131 127,616 52,342 127,016 BL-MIX-4-Clear-2 72 Black 0,4 gram Mix 4 mmol Clear 2 40 ml 2015/MB/72 339,124 3,254 5187,76 51,22 279,022 249,210 0 245,956 BL-MIX-1-Clear-3 106 Black 0,4 gram Mix 1 mmol Clear 3 40 ml 2015/MB/106 20,021 0,559 306,27 8,80 64,480 60,455 44,459 59,896 BL-MIX-2-Clear-3 107 Black 0,4 gram Mix 2 mmol Clear 3 40 ml 2015/MB/107 116,458 1,332 1781,53 20,96 139,131 127,616 22,673 126,284 BL-MIX-4-Clear-3 108 Black 0,4 gram Mix 4 mmol Clear 3 40 ml 2015/MB/108 8,611 2,889 131,72 45,47 279,022 249,210 270,411 140,210 BL-Blank-DOM-1 109 Black 0,4 gram Blank 0 mmol DOM 1 40 ml 2015/MB/109 0,292 0,065 4,47 1,03 65,3 BL-Blank-DOM-2 110 Black 0,4 gram Blank 0 mmol DOM 2 40 ml 2015/MB/110 0,046 0,051 0,71 0,80 60,1 BL-Blank-DOM-3 111 Black 0,4 gram Blank 0 mmol DOM 3 40 ml 2015/MB/111 0,029 0,044 0,44 0,70 69,0 BL-Blank-Clear-1 112 Black 0,4 gram Blank 0 mmol Clear 1 40 ml 2015/MB/112 0,011 0,010 0,17 0,15
Bl-Blank-Clear-2 113 Black 0,4 gram Blank 0 mmol Clear 2 40 ml 2015/MB/113 0,006 0,004 0,10 0,06 Bl-Blank-Clear-3 114 Black 0,4 gram Blank 0 mmol Clear 3 40 ml 2015/MB/114 0,005 0,003 0,08 0,05
BR-Blank-DOM-1 115 Brown 0,4 gram Blank 0 mmol DOM 1 40 ml 2015/MB/115 0,232 0,139 3,54 2,19 132,3 BR-Blank-DOM-2 116 Brown 0,4 gram Blank 0 mmol DOM 2 40 ml 2015/MB/116 0,239 0,121 3,66 1,90 131,9 BR-Blank-DOM-3 117 Brown 0,4 gram Blank 0 mmol DOM 3 40 ml 2015/MB/117 0,232 0,131 3,54 2,06 135,1 BR-Blank-Clear-1 118 Brown 0,4 gram Blank 0 mmol Clear 1 40 ml 2015/MB/118 0,324 0,066 4,95 1,04
BR-Blank-Clear-2 119 Brown 0,4 gram Blank 0 mmol Clear 2 40 ml 2015/MB/119 0,203 0,063 3,10 1,00 BR-Blank-Clear-3 120 Brown 0,4 gram Blank 0 mmol Clear 3 40 ml 2015/MB/120 0,243 0,077 3,72 1,21
blank-blank-DOM 121 Blank Blank blank 0 mmol DOM 40 ml 2015/MB/121 0,033 0,066 0,50 1,04 98,1
blank-blank-DOM 122 blank Blank Blank 0 mmol DOM 40ml 2015/MB/122 0,025 0,061 0,38 0,96 92,8
blank-Mix-4-DOM 123 Blank blank Mix 4 mmol DOM 40 ml 2015/MB/123 0,378 314,734 5,79 4953,33 5,8 blank-Mix-4-DOM 124 Blank Blank Mix 4 mmol DOM 40 ml 2015/MB/124 0,143 303,426 2,19 4775,35 8,3
27
Appendix B
Solutions (mg/L) Zn (mg/L) Cu (µmol/L) Zn (µmol/L) Cu
20 mmol/l Zn 1459,7 1,7 22329 27 20 mmol/l Cu 2,1 1358,0 33 21372 8 mmol/l Zn 556,5 0,5 8513 8 8 mmol/l Cu 0,4 510,5 6 8034 8 mmol/l Zn Cu 558,0 498,4 8537 7844 4 mmol/l Zn 257,9 8,9 3945 141 4 mmol/l Cu 0,6 241,8 9 3806 2 mmol/l Zn 134,8 0,1 2062 1 2 mmol/l Cu 0,1 118,5 2 1864
BR-Blank-DOM-1 115 Brown 0,4 gram Blank 0 mmol DOM 1 40 ml 2015/MB/115 0,232 0,139 3,54 2,19 132,3 BR-Blank-DOM-2 116 Brown 0,4 gram Blank 0 mmol DOM 2 40 ml 2015/MB/116 0,239 0,121 3,66 1,90 131,9 BR-Blank-DOM-3 117 Brown 0,4 gram Blank 0 mmol DOM 3 40 ml 2015/MB/117 0,232 0,131 3,54 2,06 135,1 BR-Blank-Clear-1 118 Brown 0,4 gram Blank 0 mmol Clear 1 40 ml 2015/MB/118 0,324 0,066 4,95 1,04
BR-Blank-Clear-2 119 Brown 0,4 gram Blank 0 mmol Clear 2 40 ml 2015/MB/119 0,203 0,063 3,10 1,00 BR-Blank-Clear-3 120 Brown 0,4 gram Blank 0 mmol Clear 3 40 ml 2015/MB/120 0,243 0,077 3,72 1,21
blank-blank-DOM 121 Blank Blank blank 0 mmol DOM 40 ml 2015/MB/121 0,033 0,066 0,50 1,04 98,1
blank-blank-DOM 122 blank Blank Blank 0 mmol DOM 40ml 2015/MB/122 0,025 0,061 0,38 0,96 92,8
blank-Mix-4-DOM 123 Blank blank Mix 4 mmol DOM 40 ml 2015/MB/123 0,378 314,734 5,79 4953,33 5,8 blank-Mix-4-DOM 124 Blank Blank Mix 4 mmol DOM 40 ml 2015/MB/124 0,143 303,426 2,19 4775,35 8,3
