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Gerard Cornelissen - One of the best experts on this subject based on the ideXlab platform.
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can polyethylene passive samplers predict polychlorinated biphenyls pcbs uptake by earthworms and turnips in a Biochar amended soil
Science of The Total Environment, 2019Co-Authors: Ludovica Silvani, Gerard Cornelissen, Sigurbjorg Hjartardottir, Lucie Bielska, Lucia Skulcova, Luca Nizzetto, Sarah E HaleAbstract:A pot experiment was carried out in which aged polychlorinated biphenyls (PCBs) contaminated soil was amended with Biochar, and three phases: earthworms, turnips and polyethylene (PE) passive samplers, were added simultaneously in order to investigate changes in bioavailability of PCB following Biochar amendment. Two Biochars were used: one made from rice husk in Indonesia using local techniques and the other made from mixed wood shavings using more advanced technology. The Biochars were amended at 1 and 4% doses. The overall accumulation of PCBs to the phases followed the order: earthworm lipid > PE > turnip. The rice husk Biochar reduced PCB accumulation to a greater degree than the mixed wood Biochar for all phases, however there was no effect of dose for either Biochar. Earthworm uptake was reduced between 52% and 91% for rice husk Biochar and by 19% to 63% formix wood Biochar. Turnip uptake was not significantly reduced by Biochar amendment. Phase to soil accumulation factors (PSAF) were around 0.5 for turnips, approximately 5 for PE and exceeded 100 for earthworms. This study demonstrates that both Biochars canbe a sustainable alternative for in situ soil remediation and that PE can be used as tool to simulate the uptake in earthworms and thus remediation effectiveness. (c) 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.
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Can polyethylene passive samplers predict polychlorinated biphenyls (PCBs) uptake by earthworms and turnips in a Biochar amended soil?
Elsevier, 2019Co-Authors: Ludovica Silvani, Gerard Cornelissen, Sigurbjorg Hjartardottir, Lucie Bielska, Lucia Skulcova, Luca Nizzetto, Sarah E HaleAbstract:A pot experiment was carried out in which aged polychlorinated biphenyls (PCBs) contaminated soil was amended with Biochar, and three phases: earthworms, turnips and polyethylene (PE) passive samplers, were added simultaneously in order to investigate changes in bioavailability of PCB following Biochar amendment. Two Biochars were used: one made from rice husk in Indonesia using local techniques and the other made from mixed wood shavings using more advanced technology. The Biochars were amended at 1 and 4% doses. The overall accumulation of PCBs to the phases followed the order: earthworm lipid > PE > turnip. The rice husk Biochar reduced PCB accumulation to a greater degree than the mixed wood Biochar for all phases, however there was no effect of dose for either Biochar. Earthworm uptake was reduced between 52% and 91% for rice husk Biochar and by 19% to 63% for mix wood Biochar. Turnip uptake was not significantly reduced by Biochar amendment. Phase to soil accumulation factors (PSAF) were around 0.5 for turnips, approximately 5 for PE and exceeded 100 for earthworms. This study demonstrates that both Biochars can be a sustainable alternative for in situ soil remediation and that PE can be used as tool to simulate the uptake in earthworms and thus remediation effectiveness
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Biochar from kon tiki flame curtain and other kilns effects of nutrient enrichment and kiln type on crop yield and soil chemistry
PLOS ONE, 2017Co-Authors: Gerard Cornelissen, Naba Raj Pandit, Sarah Elisabeth Hale, Hanspeter Schmidt, Jan MulderAbstract:Biochar application to soils has been investigated as a means of improving soil fertility and mitigating climate change through soil carbon sequestration. In the present work, the invasive shrub "Eupatorium adenophorum" was utilized as a sustainable feedstock for making Biochar under different pyrolysis conditions in Nepal. Biochar was produced using several different types of kilns; four sub types of flame curtain kilns (deep-cone metal kiln, steel shielded soil pit, conical soil pit and steel small cone), brick-made traditional kiln, traditional earth-mound kiln and top lift up draft (TLUD). The resultant Biochars showed consistent pH (9.1 ± 0.3), cation exchange capacities (133 ± 37 cmolc kg-1), organic carbon contents (73.9 ± 6.4%) and surface areas (35 to 215 m2/g) for all kiln types. A pot trial with maize was carried out to investigate the effect on maize biomass production of the Biochars made with various kilns, applied at 1% and 4% dosages. Biochars were either pretreated with hot or cold mineral nutrient enrichment (mixing with a nutrient solution before or after cooling down, respectively), or added separately from the same nutrient dosages to the soil. Significantly higher CEC (P 0.05). At a dosage of 1% Biochar, the hot nutrient-enriched Biochar led to significant increases of 153% in above ground biomass production compared to cold nutrient-enriched Biochar and 209% compared to Biochar added separately from the nutrients. Liquid nutrient enhancement of Biochar thus improved fertilizer effectiveness compared to separate application of Biochar and fertilizer.
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quantifying the total and bioavailable polycyclic aromatic hydrocarbons and dioxins in Biochars
Environmental Science & Technology, 2012Co-Authors: Sarah E Hale, Andrew R Zimmerman, Hans Peter H Arp, Johannes Lehmann, David W Rutherford, Robert Thomas Bachmann, Victor Shitumbanuma, Adam Otoole, Kristina Sundqvist, Gerard CornelissenAbstract:Biochar soil amendment is advocated to mitigate climate change and improve soil fertility. A concern though, is that during Biochar preparation PAHs and dioxins are likely formed. These contaminants can possibly be present in the Biochar matrix and even bioavailable to exposed organisms. Here we quantify total and bioavailable PAHs and dioxins in a suite of over 50 Biochars produced via slow pyrolysis between 250 and 900 °C, using various methods and biomass from tropical, boreal, and temperate areas. These slow pyrolysis Biochars, which can be produced locally on farms with minimum resources, are also compared to Biochar produced using the industrial methods of fast pyrolysis and gasification. Total concentrations were measured with a Soxhlet extraction and bioavailable concentrations were measured with polyoxymethylene passive samplers. Total PAH concentrations ranged from 0.07 μg g–1 to 3.27 μg g–1 for the slow pyrolysis Biochars and were dependent on biomass source, pyrolysis temperature, and time. Wi...
Andrew R Zimmerman - One of the best experts on this subject based on the ideXlab platform.
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a review of Biochar as a low cost adsorbent for aqueous heavy metal removal
Critical Reviews in Environmental Science and Technology, 2016Co-Authors: Mandu Inyang, Yingwen Xue, Pratap Pullammanappallil, Bin Gao, Ahmed Mosa, Andrew R Zimmerman, Yong Sik Ok, Ying Yao, Xinde CaoAbstract:ABSTRACTAs a low-cost adsorbent, Biochar can be used as a low-cost adsorbent for wastewater treatment, particularly with respect to treating heavy metals in wastewater. A number of studies have demonstrated effective removal of heavy metals from aqueous solutions by Biochar and, in some cases, proven the superiority of Biochars to activated carbons. Among several factors affecting the sorption ability of Biochars, feedstock materials play a significant role. This review incorporates existing literature to understand the overall sorption behavior of heavy metals on Biochar adsorbents. Depending on the Biochar type, heavy metal can be removed by different mechanisms such as complexation, physical sorption, precipitation and electrostatic interactions. Mathematical sorption models can be used to understand the efficiency of Biochar at removing heavy metals, and promote the application of Biochar technology in water treatment.
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sorption of heavy metals on chitosan modified Biochars and its biological effects
Chemical Engineering Journal, 2013Co-Authors: Bin Gao, Andrew R Zimmerman, Yanmei Zhou, June Fang, Yining Sun, Xinde CaoAbstract:Abstract In this work, chitosan-modified Biochars were synthesized in efforts to produce a low-cost adsorbent for heavy metal environmental remediation. Characterization results showed that the coating of chitosan on Biochar surfaces could improve its performance as a soil amendment or an adsorbent. Batch sorption experiments showed that, compared to the unmodified Biochars, almost all the chitosan-modified Biochars showed enhanced removal of three metals (i.e., Pb2+, Cu2+, and Cd2+) from solution. Further investigations of lead sorption on chitosan-modified bamboo Biochar (i.e., BB-C) indicated that, although sorption kinetics were slow, BB-C had a relatively high Langmuir lead sorption capacity of 14.3 mg/g Biochar (71.5 mg/g chitosan). Sorption of lead on the chitosan-modified Biochar greatly reduced its metal toxicity. Both seed germination rate and seedling growth of the Pb-laden BB-C were similar to that of control groups without lead. In addition, uptake of lead by plants was reduced about 60% when lead was sorbed onto the chitosan-modified Biochar. This work suggests that chitosan-modified Biochars may be used as an effective, low-cost, and environmental-friendly adsorbent to remediate heavy metal contamination in the environment.
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organic carbon and nutrient release from a range of laboratory produced Biochars and Biochar soil mixtures
Geoderma, 2013Co-Authors: Atanu Mukherjee, Andrew R ZimmermanAbstract:article i nfo Keywords: Biochar Nutrients Leaching Sorption Dissolved organic carbon Phosphorus Biochar has shown promise as a soil amendment that increases carbon sequestration and fertility, but its ef- fects on dissolved organic carbon (DOC), nitrogen (N) and phosphorus (P) cycling and loss is not well under- stood. Here, nutrient release from a variety of new and aged Biochars, pure and mixed with soils, is examined using batch extraction and column leaching. In successive batch extractions of Biochar, cumulative losses were about 0.1-2, 0.5-8 and 5-100% of the total C, N and P initially present, respectively, with greater re- leases from Biochars made at lower temperature and from grass. Ammonium was usually the most abundant N form in leachates but nitrate was also abundant in some Biochars, while organic N and P represented as much as 61% and 93% of the total N and P lost, respectively. Release of DOC, N and P into water was correlated with Biochar volatile matter content and acid functional group density. However, P release via Mehlich-1 ex- traction was more strongly related to ash content, suggesting a mineral-associated P fraction. Columns with soil/Biochar mixtures showed evidence of both soil nutrient sorption by Biochar and Biochar nutrient sorp- tion by soil, depending upon Biochar and soil type. This study demonstrates that Biochars contain a range of nutrient forms with different release rates, explaining Biochar's variable effect on soil fertility with soil
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quantifying the total and bioavailable polycyclic aromatic hydrocarbons and dioxins in Biochars
Environmental Science & Technology, 2012Co-Authors: Sarah E Hale, Andrew R Zimmerman, Hans Peter H Arp, Johannes Lehmann, David W Rutherford, Robert Thomas Bachmann, Victor Shitumbanuma, Adam Otoole, Kristina Sundqvist, Gerard CornelissenAbstract:Biochar soil amendment is advocated to mitigate climate change and improve soil fertility. A concern though, is that during Biochar preparation PAHs and dioxins are likely formed. These contaminants can possibly be present in the Biochar matrix and even bioavailable to exposed organisms. Here we quantify total and bioavailable PAHs and dioxins in a suite of over 50 Biochars produced via slow pyrolysis between 250 and 900 °C, using various methods and biomass from tropical, boreal, and temperate areas. These slow pyrolysis Biochars, which can be produced locally on farms with minimum resources, are also compared to Biochar produced using the industrial methods of fast pyrolysis and gasification. Total concentrations were measured with a Soxhlet extraction and bioavailable concentrations were measured with polyoxymethylene passive samplers. Total PAH concentrations ranged from 0.07 μg g–1 to 3.27 μg g–1 for the slow pyrolysis Biochars and were dependent on biomass source, pyrolysis temperature, and time. Wi...
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an index based approach to assessing recalcitrance and soil carbon sequestration potential of engineered black carbons Biochars
Environmental Science & Technology, 2012Co-Authors: Omar R Harvey, Andrew R Zimmerman, Lijung Kuo, Patrick Louchouarn, James E Amonette, Bruce E HerbertAbstract:The ability of engineered black carbons (or Biochars) to resist abiotic and, or biotic degradation (herein referred to as recalcitrance) is crucial to their successful deployment as a soil carbon sequestration strategy. A new recalcitrance index, the R50, for assessing Biochar quality for carbon sequestration is proposed. The R50 is based on the relative thermal stability of a given Biochar to that of graphite and was developed and evaluated with a variety of Biochars (n = 59), and soot-like black carbons. Comparison of R50, with Biochar physicochemical properties and Biochar-C mineralization revealed the existence of a quantifiable relationship between R50 and Biochar recalcitrance. As presented here, the R50 is immediately applicable to pre-land application screening of Biochars into Class A (R50 ≥ 0.70), Class B (0.50 ≤ R50 < 0.70) or Class C (R50 < 0.50) recalcitrance/carbon sequestration classes. Class A and Class C Biochars would have carbon sequestration potential comparable to soot/graphite and un...
Baoshan Xing - One of the best experts on this subject based on the ideXlab platform.
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Properties of Biochar-amended soils and their sorption of imidacloprid, isoproturon, and atrazine
Science of the Total Environment, 2016Co-Authors: Jie Jin, Mingjie Kang, Zezhen Pan, Fengchang Wu, Ke Sun, Baoshan XingAbstract:Biochars produced from rice straw, wheat straw and swine manure at 300, 450 and 600 °C were added to soil at 1, 5, 10, or 20% levels to determine whether they would predictably reduce the pore water concentration of imidacloprid, isoproturon, and atrazine. The sorption capacity of the mixtures increased with increasing Biochar amounts. The enhanced sorption capacity could be attributed to the increased organic carbon (OC) content and surface area (SA) as well as the decreased hydrophobicity. Biochar dominated the overall sorption when its content was above 5%. The OC contents of the mixtures with 10% and 20% Biochar were generally lower than the predicted values. This implies possible interaction between soil components and Biochar and/or the effect of Biochar oxidation. For soils amended with Biochars produced at 300 °C, the N2SA (N2-SA) values were underestimated. The predicted CO2SA (CO2-SA) values of the mixtures at the Biochar content of 10% and 20% were generally higher than the experimental values. Sorption of imidacloprid to the soils amended with Biochar at 10% and 20% levels, excluding the soils amended with rice (SR300) and wheat (SW300) straw-derived Biochar produced at 300 °C, was lower than the predicted value. For SR300 and SW300, the intrinsic sorption capacity of Biochar was enhanced by 1.3-5.6 times, depending on the Biochar, solute concentration, and Biochar dose. This study indicates that Biochars would be helpful to stabilize the soil contaminated with imidacloprid, isoproturon, and atrazine, but the sorption capacity of the mixtures could exceed or fall short of predicted values without assuming a cross-effect between soil and Biochar.
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selective removal of polycyclic aromatic hydrocarbons pahs from soil washing effluents using Biochars produced at different pyrolytic temperatures
Bioresource Technology, 2014Co-Authors: Helian Li, Ronghui Qu, Fang He, Chao Li, Baoshan XingAbstract:Abstract Wheat straw Biochars produced at 400, 600 and 800 °C (BC400, BC600 and BC800) were used to selectively adsorb PAHs from soil washing effluents. For soil washing effluents contained Phenanthrene (PHE), Fluoranthene (FLU), Pyrene (PYR) and Triton X-100 (TX100), Biochars at 2 (for BC800) or 6 g L −1 (for BC400 and BC600) can remove 71.8–98.6% of PAHs while recover more than 87% of TX100. PAH removals increase with increasing Biochar dose. However, excess Biochar is detrimental to the recovery of surfactant. For a specific Biochar dose, PAH removal and TX100 loss increase with increasing pyrolytic temperature. For BC400 and BC600, PAH removal follows the order of PHE > FLU > PYR, while the order is reversed with PYR > FLU > PHE for BC800. Biochars have much higher sorption affinity for PAHs than for TX100. It is therefore suggested that Biochar is a good alternative for selective adsorption of PAHs and recovery of TX100 in soil washing process.
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single solute and bi solute sorption of phenanthrene and dibutyl phthalate by plant and manure derived Biochars
Science of The Total Environment, 2014Co-Authors: Jie Jin, Mingjie Kang, Ke Sun, Ye Zhao, Bo Gao, Ziying Wang, Xitao Liu, Yingcheng Bai, Baoshan XingAbstract:Abstract The spatial arrangement of Biochar and the exact underlying interaction mechanisms of Biochar and hydrophobic organic compounds both remain largely unknown. The sorption of dibutyl phthalate (DBP) and phenanthrene (PHE) to plant- and manure-derived Biochars in both single- and bi-solute systems was investigated. The significant positive relation between surface polarity and ash content suggests that minerals benefit the external distribution of polar groups on particle surfaces. PHE and DBP sorption by the Biochars was regulated by their surface polarity. The PHE generally displayed a pronounced enhancement of DBP sorption, likely resulting from the formation of Biochar–PHE–DBP complexes, suggesting that DBP and PHE had different sorption sites on the Biochars. The enhancement of Cd 2 + (a soft Lewis acid) on DBP sorption implied that π–π interactions should not dominate DBP sorption by Biochars. The influence of Cd 2 + on PHE sorption by Biochars would depend on the balance between suppressive sorption by Cd 2 + PHE bonding and enhanced sorption by Cd 2 + -complexed functionalities, and the amounts of Cd 2 + adsorbed by Biochars determined the relative role of increased sorption by Cd 2 + in the overall PHE sorption.
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characterization and influence of Biochars on nitrous oxide emission from agricultural soil
Environmental Pollution, 2013Co-Authors: Zhenyu Wang, Hao Zheng, Ye Luo, Xia Deng, S J Herbert, Baoshan XingAbstract:Abstract Extensive use of Biochar to mitigate N2O emission is limited by the lack of understanding on the exact mechanisms altering N2O emissions from Biochar-amended soils. Biochars produced from giant reed were characterized and used to investigate their influence on N2O emission. Responses of N2O emission varied with pyrolysis temperature, and the reduction order of N2O emission by Biochar (BC) was: BC200 ≈ BC600 > BC500 ≈ BC300 ≈ BC350 > BC400. The reduced emission was attributed to enhanced N immobilization and decreased denitrification in the Biochar-amended soils. The remaining polycyclic aromatic hydrocarbons (PAHs) in low-temperature Biochars (300–400 °C) played a major role in reducing N2O emission, but not for high-temperature Biochars (500–600 °C). Removal of phenolic compounds from low-temperature (200–400 °C) Biochars resulted in a surprising reduction of N2O emission, but the mechanism is still unknown. Overall, adding giant reed Biochars could reduce N2O evolution from agricultural soil, thus possibly mitigating global warming.
Stephen Joseph - One of the best experts on this subject based on the ideXlab platform.
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Biochar aging in contaminated soil promotes zn immobilization due to changes in Biochar surface structural and chemical properties
Science of The Total Environment, 2018Co-Authors: Abhay Kumar, Stephen Joseph, L Tsechansky, Inga J Schreiter, Karen Privat, Christoph Schüth, Ellen R GraberAbstract:Adding Biochar to Zn-contaminated soil can immobilize excess Zn and promote plant biomass growth. This was seen previously over the course of a 180-day planted pot trial involving two types of Biochar (cattle manure, CM, and grain husk, GH) in a Zn-contaminated soil. Both Biochars alleviated Zn-induced phytotoxicity to Ficus by immobilizing Zn and reducing its uptake by the plant, but to different extents. The aim of the current study was to delve into the in-soil mechanisms involved in Biochar-mediated Zn immobilization. Biochar particles were excavated from the pot soils. Fresh and aged Biochar particles were examined by high-resolution scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscopy (EDS), field-emission electron probe micro-analyzer (EPMA), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). The physical and chemical properties of the Biochars had changed over the 180 days. SEM-EDS and EPMA indicated that organo-mineral micro-agglomerates had formed on Biochar surfaces and in pores. Some of the Zn immobilized by the Biochars was bound in the organo-mineral complexes of these agglomerates. XPS and FTIR showed that the complexes had a high concentration of oxygenated functional groups which facilitated Zn binding and encapsulation. The micro-agglomerates were similar in structure and composition to those observed on Biochars having resided for much longer times in soils, or having been subjected to accelerated aging. Overall, Zn immobilization by the CM Biochar was greater than by the GH Biochar, due to its higher alkalinity, higher concentration of available negatively charged groups, and greater accretion of organo-mineral layers. These findings are suggestive that Biochar-assisted phytorestoration of heavy metal-contaminated soils can be optimized through selection of Biochar having such traits. It is hypothesized that metals may be continually taken up in such micro-agglomerates, since they continue to form over the lifetime of the Biochar in the soil.
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Biochar aging in contaminated soil promotes zn immobilization due to changes in Biochar surface structural and chemical properties
Science of The Total Environment, 2018Co-Authors: Abhay Kumar, Stephen Joseph, L Tsechansky, Inga J Schreiter, Karen Privat, Christoph Schüth, Ellen R GraberAbstract:Adding Biochar to Zn-contaminated soil can immobilize excess Zn and promote plant biomass growth. This was seen previously over the course of a 180-day planted pot trial involving two types of Biochar (cattle manure, CM, and grain husk, GH) in a Zn-contaminated soil. Both Biochars alleviated Zn-induced phytotoxicity to Ficus by immobilizing Zn and reducing its uptake by the plant, but to different extents. The aim of the current study was to delve into the in-soil mechanisms involved in Biochar-mediated Zn immobilization. Biochar particles were excavated from the pot soils. Fresh and aged Biochar particles were examined by high-resolution scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscopy (EDS), field-emission electron probe micro-analyzer (EPMA), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). The physical and chemical properties of the Biochars had changed over the 180 days. SEM-EDS and EPMA indicated that organo-mineral micro-agglomerates had formed on Biochar surfaces and in pores. Some of the Zn immobilized by the Biochars was bound in the organo-mineral complexes of these agglomerates. XPS and FTIR showed that the complexes had a high concentration of oxygenated functional groups which facilitated Zn binding and encapsulation. The micro-agglomerates were similar in structure and composition to those observed on Biochars having resided for much longer times in soils, or having been subjected to accelerated aging. Overall, Zn immobilization by the CM Biochar was greater than by the GH Biochar, due to its higher alkalinity, higher concentration of available negatively charged groups, and greater accretion of organo-mineral layers. These findings are suggestive that Biochar-assisted phytorestoration of heavy metal-contaminated soils can be optimized through selection of Biochar having such traits. It is hypothesized that metals may be continually taken up in such micro-agglomerates, since they continue to form over the lifetime of the Biochar in the soil.
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Using poultry litter Biochars as soil amendments
Soil Research, 2008Co-Authors: K.y. Chan, Adriana Downie, L. Van Zwieten, I. Meszaros, Stephen JosephAbstract:Despite the recent interest in Biochars as soil amendments for improving soil quality and increasing soil carbon sequestration, there is inadequate knowledge on the soil amendment properties of these materials produced from different feed stocks and under different pyrolysis conditions. This is particularly true for Biochars produced from animal origins. Two Biochars produced from poultry litter under different conditions were tested in a pot trial by assessing the yield of radish (Raphanus sativus var. Long Scarlet) as well as the soil quality of a hardsetting Chromosol (Alfisol). Four rates of Biochar (0, 10, 25, and 50 t/ha), with and without nitrogen application (100 kg N/ha) were investigated. Both Biochars, without N fertiliser, produced similar increases in dry matter yield of radish, which were detectable at the lowest application rate, 10 t/ha. The yield increase (%), compared with the unamended control rose from 42% at 10 t/ha to 96% at 50 t/ha of Biochar application. The yield increases can be attributed largely to the ability of these Biochars to increase N availability. Significant additional yield increases, in excess of that due to N fertiliser alone, were observed when N fertiliser was applied together with the Biochars, highlighting the other beneficial effects of these Biochars. In this regard, the non activated poultry litter Biochar produced at lower temperature (450°C) was more effective than the activated Biochar produced at higher temperature (550°C), probably due to higher available P content. Biochar addition to the hardsetting soil resulted in significant but different changes in soil chemical and physical properties, including increases in C, N, pH, and available P, but reduction in soil strength. These different effects of the 2 different Biochars can be related to their different characteristics. Significantly different changes in soil biology in terms of microbial biomass and earthworm preference properties were also observed between the 2 Biochars, but the underlying mechanisms require further research. Our research highlights the importance of feedstock and process conditions during pyrolysis on the properties and, hence, soil amendment values of Biochars.
Xinde Cao - One of the best experts on this subject based on the ideXlab platform.
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a review of Biochar as a low cost adsorbent for aqueous heavy metal removal
Critical Reviews in Environmental Science and Technology, 2016Co-Authors: Mandu Inyang, Yingwen Xue, Pratap Pullammanappallil, Bin Gao, Ahmed Mosa, Andrew R Zimmerman, Yong Sik Ok, Ying Yao, Xinde CaoAbstract:ABSTRACTAs a low-cost adsorbent, Biochar can be used as a low-cost adsorbent for wastewater treatment, particularly with respect to treating heavy metals in wastewater. A number of studies have demonstrated effective removal of heavy metals from aqueous solutions by Biochar and, in some cases, proven the superiority of Biochars to activated carbons. Among several factors affecting the sorption ability of Biochars, feedstock materials play a significant role. This review incorporates existing literature to understand the overall sorption behavior of heavy metals on Biochar adsorbents. Depending on the Biochar type, heavy metal can be removed by different mechanisms such as complexation, physical sorption, precipitation and electrostatic interactions. Mathematical sorption models can be used to understand the efficiency of Biochar at removing heavy metals, and promote the application of Biochar technology in water treatment.
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sorption of heavy metals on chitosan modified Biochars and its biological effects
Chemical Engineering Journal, 2013Co-Authors: Bin Gao, Andrew R Zimmerman, Yanmei Zhou, June Fang, Yining Sun, Xinde CaoAbstract:Abstract In this work, chitosan-modified Biochars were synthesized in efforts to produce a low-cost adsorbent for heavy metal environmental remediation. Characterization results showed that the coating of chitosan on Biochar surfaces could improve its performance as a soil amendment or an adsorbent. Batch sorption experiments showed that, compared to the unmodified Biochars, almost all the chitosan-modified Biochars showed enhanced removal of three metals (i.e., Pb2+, Cu2+, and Cd2+) from solution. Further investigations of lead sorption on chitosan-modified bamboo Biochar (i.e., BB-C) indicated that, although sorption kinetics were slow, BB-C had a relatively high Langmuir lead sorption capacity of 14.3 mg/g Biochar (71.5 mg/g chitosan). Sorption of lead on the chitosan-modified Biochar greatly reduced its metal toxicity. Both seed germination rate and seedling growth of the Pb-laden BB-C were similar to that of control groups without lead. In addition, uptake of lead by plants was reduced about 60% when lead was sorbed onto the chitosan-modified Biochar. This work suggests that chitosan-modified Biochars may be used as an effective, low-cost, and environmental-friendly adsorbent to remediate heavy metal contamination in the environment.