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Mechanisms of antimony adsorption onto soybean stover-derived biochar in aqueous solutions
Vithanage, M.,Rajapaksha, A.U.,Ahmad, M.,Uchimiya, M.,Dou, X.,Alessi, D.S.,Ok, Y.S. Academic Press 2015 Journal of environmental management Vol.151 No.-
Limited mechanistic knowledge is available on the interaction of biochar with trace elements (Sb and As) that exist predominantly as oxoanions. Soybean stover biochars were produced at 300 <SUP>o</SUP>C (SBC300) and 700 <SUP>o</SUP>C (SBC700), and characterized by BET, Boehm titration, FT-IR, NMR and Raman spectroscopy. Bound protons were quantified by potentiometric titration, and two acidic sites were used to model biochar by the surface complexation modeling based on Boehm titration and NMR observations. The zero point of charge was observed at pH 7.20 and 7.75 for SBC300 and SBC700, respectively. Neither antimonate (Sb(V)) nor antimonite (Sb(III)) showed ionic strength dependency (0.1, 0.01 and 0.001 M NaNO<SUB>3</SUB>), indicating inner sphere complexation. Greater adsorption of Sb(III) and Sb(V) was observed for SBC300 having higher -OH content than SBC700. Sb(III) removal (85%) was greater than Sb(V) removal (68%). Maximum adsorption density for Sb(III) was calculated as 1.88 x 10<SUP>-6</SUP> mol m<SUP>-2</SUP>. The Triple Layer Model (TLM) successfully described surface complexation of Sb onto soybean stover-derived biochar at pH 4-9, and suggested the formation of monodentate mononuclear and binuclear complexes. Spectroscopic investigations by Raman, FT-IR and XPS further confirmed strong chemisorptive binding of Sb to biochar surfaces.
Acid-activated biochar increased sulfamethazine retention in soils.
Vithanage, Meththika,Rajapaksha, Anushka Upamali,Zhang, Ming,Thiele-Bruhn, S?ren,Lee, Sang Soo,Ok, Yong Sik Ecomed 2015 Environmental Science and Pollution Research Vol.22 No.3
<P>Sulfamethazine (SMZ) is an ionizable and highly mobile antibiotic which is frequently found in soil and water environments. We investigated the sorption of SMZ onto soils amended with biochars (BCs) at varying pH and contact time. Invasive plants were pyrolyzed at 700 C and were further activated with 30 % sulfuric (SBBC) and oxalic (OBBC) acids. The sorption rate of SMZ onto SBBC and OBBC was pronouncedly pH dependent and was decreased significantly when the values of soil pH increased from 3 to 5. Modeled effective sorption coefficients (K D,eff) values indicated excellent sorption on SBBC-treated loamy sand and sandy loam soils for 229 and 183 L/kg, respectively. On the other hand, the low sorption values were determined for OBBC- and BBC700-treated loamy sand and sandy loam soils. Kinetic modeling demonstrated that the pseudo second order model was the best followed by intra-particle diffusion and the Elovich model, indicating that multiple processes govern SMZ sorption. These findings were also supported by sorption edge experiments based on BC characteristics. Chemisorption onto protonated and ligand containing functional groups of the BC surface, and diffusion in macro-, meso-, and micro-pores of the acid-activated BCs are the proposed mechanisms of SMZ retention in soils. Calculated and experimental q e (amount adsorbed per kg of the adsorbent at equilibrium) values were well fitted to the pseudo second order model, and the predicted maximum equilibrium concentration of SBBC for loamy sand soils was 182 mg/kg. Overall, SBBC represents a suitable soil amendment because of its high sorption rate of SMZ in soils.</P>
Vithanage, M.,Rajapaksha, A. U.,Wijesekara, H.,Weerarathne, N.,Ok, Y. S. Springer Science + Business Media 2014 Environmental Earth Sciences Vol.71 No.2
Inorganic arsenic (As) pesticides have been widely used for decades in many countries. However, insufficient data are available on the chemical speciation of inorganic arsenicals in tropical paddy soils. Inorganic As-containing pesticides were used in tropical countries, a few decades ago, however, their fate have not been studied. Hence, the objective of this study was to determine fractionation of inorganic arsenicals and to assess As lability with/without fertilizer application using a static incubation experiment. Eight soils from wet and dry regions of Sri Lanka were amended with 1,000 mg/kg arsenate for this purpose. The FT-IR and XRF results suggested that soils in the wet region were rich in Fe/Al-oxides. Paddy soils in the dry zone showed high As lability. These low-humic gley soils have low Fe/Al oxyhydroxide and alkaline pH. In contrast, the wet zone had soils with higher As retention capacity, high amounts of Fe/Al oxyhydroxide, and acidic pH. Arsenic lability increased considerably 30 days after fertilizer application. Overall, As lability was mainly influenced by soil mineralogical and chemical properties, i.e., Fe/Al oxyhydroxide, pH, organic matter, and fertilizer application.
Interaction of arsenic with biochar in soil and water: A critical review
Vithanage, Meththika,Herath, Indika,Joseph, Stephen,Bundschuh, Jochen,Bolan, Nanthi,Ok, Yong Sik,Kirkham, M.B.,Rinklebe, Jö,rg Elsevier 2017 Carbon Vol.113 No.-
<P>Biochar exhibits a great potential to act as a universally applicable material for water and soil remediation due to extensive availability of feedstocks and favorable physio-chemical surface characteristics; nevertheless, studies related to its application on the remediation of toxic metalloids are relatively rare. Hence, this review highlights biochar production technologies, biochar properties, and recent advances in the removal and immobilization of a major metalloid contaminant, As in water and soil. It also covers surface modification of biochars to enhance As removal and microbial properties in biochar amended soil. Experimental studies related to the adsorption behaviors of biochar and the underlying mechanisms proposed to explain them have been comprehensively reviewed. Compared to the number of research publications in SCOPUS database on 'Biochar+Water' (approximate to 1290 - Scopus), the attention drawn to examine the behavior of biochar on the remediation of As is limited (approximate to 85 - Scopus). Because of the toxicity of As, the subject urgently needs more consideration. In addition to covering the topics listed above, this review identifies research gaps in the use of biochar as an adsorbent for As, and proposes potential areas for future application of biochars. (C) 2016 Elsevier Ltd. All rights reserved.</P>
Animal carcass burial management: implications for sustainable biochar use
Vithanage Meththika,Mayakaduwage S. S.,Gunarathne Viraj,Rajapaksha Anushka Upamali,Ahmad Mahtab,Abduljabbar Adel,Usman Adel,Al-Wabel Mohammad I.,Ippolito James A.,Ok Yong Sik 한국응용생명화학회 2021 Applied Biological Chemistry (Appl Biol Chem) Vol.64 No.6
This review focuses on existing technologies for carcass and corpse disposal and potential alternative treatment strategies. Furthermore, key issues related to these treatments (e.g., carcass and corpse disposal events, available methods, performances, and limitations) are addressed in conjunction with associated environmental impacts. Simultaneously, various treatment technologies have been evaluated to provide insights into the adsorptive removal of specific pollutants derived from carcass disposal and management. In this regard, it has been proposed that a low-cost pollutant sorbent may be utilized, namely, biochar. Biochar has demonstrated the ability to remove (in)organic pollutants and excess nutrients from soils and waters; thus, we identify possible biochar uses for soil and water remediation at carcass and corpse disposal sites. To date, however, little emphasis has been placed on potential biochar use to manage such disposal sites. We highlight the need for strategic efforts to accurately assess biochar effectiveness when applied towards the remediation of complex pollutants produced and circulated within carcass and corpse burial systems.
Vithanage, Meththika,Bandara, Tharanga,Al-Wabel, Mohammad I.,Abduljabbar, Adel,Usman, Adel R. A.,Ahmad, Mahtab,Ok, Yong Sik Informa UK (TaylorFrancis) 2018 Communications in soil science and plant analysis Vol.49 No.5
<P>Woody biochars derived by pyrolyzing Gliricidia sepium at 300 degrees C and 500 degrees C and a waste byproduct of same biomass from a bioenergy industry (BC700) were tested for their effect on soil enzymes activities and available form of heavy metals in multi-metals contaminated soil. Pot experiments were conducted during 6 weeks with tomato (Lycopersicon esculentum L.) at biochar application rates, 1, 2.5, and 5% (w/w). A reduction in polyphenol oxidase with biochars produced at increasing pyrolysis temperature compared to the control whereas the maximum activity of dehydrogenase and catalase was observed in 1% BC500 and 2.5% BC300, respectively. Soil available form of Ni, Mn, and Cr were reduced by 55, 70% and 80% in 5% BC700 amended soil, respectively. The highest geometric mean of enzyme activities was observed in 2.5% BC300 treatment. Overall the application of high dosages of high temperature derived biochar masks/deteriorates soil enzyme activities but immobilizes bioavailable heavy metals and reduces toxicity.</P>
Vithanage, M.,Rajapaksha, A.U.,Tang, X.,Thiele-Bruhn, S.,Kim, K.H.,Lee, S.E.,Ok, Y.S. Academic Press 2014 Journal of environmental management Vol.141 No.-
Sulfonamides (SAs) are one of the most frequently used antibiotics in the veterinary industry, showing high mobility in soils. Objectives of this research were to determine the sorption, distribution coefficients and involvement of different ionic forms of sulfamethazine (SMZ), a representative SAs, and to evaluate the transport of SMZ in biochar treated soils. Biochars were produced from an invasive plant, burcucumber (Sicyos angulatus L.), under slow pyrolysis conditions at peak temperatures of 300 <SUP>o</SUP>C (biochar-300) and 700 <SUP>o</SUP>C (biochar-700), respectively. The abilities of the biochars to retain SMZ in loamy sand and sandy loam soils were examined under different pHs and SMZ loadings. Soil column experiments were performed with and without biochars addition. Results showed that biochar-700 had a high degree of SMZ retention, with resultant decreased pH in both soils. Modeled effective sorption coefficients (K<SUB>D,eff</SUB>) values indicated that the observed high SMZ retention at pH 3 could be attributed to the π-π electron donor-acceptor interaction and electrostatic cation exchange, whereas at pH 5 and 7, cation exchange was the main mechanisms responsible. There was no temporal retardation of SMZ in biochar treated soil as compared to the untreated soil. However, biochar-700 treatment achieved up to 89% and 82% increase in the SMZ retention in sandy loam and loamy sand soils, respectively. The overall results demonstrated that burcucumber biochar produced at higher temperature was effective in reducing the mobility of SMZ in the studied soils.