Determining soil quality in urban agricultural regions by soil enzyme-based index

Igalavithana, A. D.,Farooq, M.,Kim, K. H.,Lee, Y. H.,Qayyum, M. F.,Al-Wabel, M. I.,Lee, S. S.,Ok, Y. S. Springer Science + Business Media 2017 Environmental geochemistry and health Vol.39 No.6

Metal(loid) immobilization in soils with biochars pyrolyzed in N₂ and CO₂ environments

Igalavithana, Avanthi Deshani,Yang, Xiao,Zahra, Hilda Rizkia,Tack, Filip M.G.,Tsang, Daniel C.W.,Kwon, Eilhann E.,Ok, Yong Sik Elsevier 2018 Science of the Total Environment Vol.630 No.-

<P><B>Abstract</B></P> <P>Previous studies indicated that using CO<SUB>2</SUB> as a reaction agent in the pyrolysis of biomass led to an enhanced generation of syngas <I>via</I> direct reaction between volatile organic carbons (VOCs) evolved from the thermal degradation of biomass and CO<SUB>2</SUB>. In addition, the physico-chemical properties of biochar in CO<SUB>2</SUB> were modified. In this current study, biochars generated from red pepper stalks in N<SUB>2</SUB> and CO<SUB>2</SUB> (RPS-N and RPS-C, respectively) were tested for their effects on the immobilization of Pb, Cd, Zn, and As in contaminated soils. Soils were incubated for one month with 2.5% of RPS, and two biochars (<I>i.e.</I>, RPS-N and RPS-C) at 25°C. After the incubation period soils were analyzed to determine the amendment effects on the behavior of metal(loid)s. The potential availability and mobility kinetics of metal(loid)s were assessed by single extraction of ammonium acetate and consecutive extraction of calcium chloride, respectively. Sequential extraction was used to further examine potential changes in geochemical fractions of metal(loid)s. The increased soil pH induced by application of the biochars reduced the potentially available Pb, Cd, and Zn, while RPS-C significantly reduced Pb due to the high surface area and aromaticity of RPS-C. However, RPS-C mobilized potentially available As compared to RPS-N due to the increased soil pH. Biochars reduced the mobility kinetics of Pb, Cd, and Zn, and RPS-N effectuated the greatest reduction of As mobility. The RPS-C increased the Fe and Mn oxides, hydroxide, and organically bound Pb, while both biochars and RPS-N increased residual Cd and Zn, and organically bound As, respectively. When considering the two biochars, RPS-C was highly effective for immobilization of Pb in soils, but it had no effect on Cd and Zn and a negative effect on As. In addition, RPS-C significantly increased the total exchangeable cations in soils.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Biochars markedly reduced Cd, Pb and Zn mobility in soils. </LI> <LI> Biochar pyrolyzed in CO<SUB>2</SUB> most effectively immobilized Pb. </LI> <LI> Biochar pyrolyzed in CO<SUB>2</SUB> increases As mobility more. </LI> <LI> More siloxane groups present in biochar pyrolysed in CO<SUB>2</SUB>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Soil lead immobilization by biochars in short-term laboratory incubation studies

Igalavithana, Avanthi Deshani,Kwon, Eilhann E.,Vithanage, Meththika,Rinklebe, Jö,rg,Moon, Deok Hyun,Meers, Erik,Tsang, Daniel C.W.,Ok, Yong Sik Pergamon 2019 Environment international Vol.127 No.-

<P><B>Abstract</B></P> <P>Exchangeable lead (Pb) extracted by ammonium acetate from three independent incubation studies was assessed to understand the influence of feedstock, pyrolysis temperatures, and production conditions on Pb immobilization capacities of different biochars. Vegetable waste biochar, pine cone, wood bark, cocopeat, red pepper stalk, and palm kernel shell were used as feedstocks (food supply and agricultural wastes) to produce biochars at 200–650 °C with and without N<SUB>2</SUB>/CO<SUB>2</SUB>. Biochars were applied at 5 and 2.5% (w w<SUP>−1</SUP>) to a Pb contaminated (i.e., 1445 mg kg<SUP>−1</SUP>) agricultural soil collected near an old mine. Lead immobilization in biochar treated soils at the end of incubation period was normalized per gram of biochar applied. Biochar produced from vegetable waste at 500 °C showed the highest Pb immobilization (87%) and highest total exchangeable cations (13.5 cmol<SUB>(+)</SUB> kg<SUP>−1</SUP>) at the end of the 45 d incubation period. However, on the basis of Pb immobilization per gram of biochar, red pepper stalk biochar produced in CO<SUB>2</SUB> at 650 °C was the best in Pb immobilization (0.09 mg kg<SUP>−1</SUP> g<SUP>−1</SUP> biochar) compared to the other biochars. The enhanced ability to immobilize Pb by biochar produced in CO<SUB>2</SUB> could be due to the presence of siloxanes (SiOSi) on biochar surface. Pearson correlation analysis revealed that alkaline pH, ash%, and N% of biochars influence in Pb immobilization and exchangeable cation availability in soil. Biochar production atmosphere considerably change its properties that influence Pb immobilization. Further studies are needed on the modification of properties and Pb immobilization by biochars produced from various feedstocks in CO<SUB>2</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Biochar production feedstock and temperature affect Pb immobilization in soil. </LI> <LI> Pb immobilization by biochar can be enhanced by mixing feedstocks. </LI> <LI> Biochar produced in CO<SUB>2</SUB> showed the highest Pb immobilization ability. </LI> <LI> Biochar produced in CO<SUB>2</SUB> increased the exchangeable cations in soil. </LI> </UL> </P>

Correction to: Determining soil quality in urban agricultural regions by soil enzyme-based index

Igalavithana, Avanthi Deshani,Farooq, Muhammad,Kim, Kye-Hoon,Lee, Young-Han,Qayyum, Muhammad Farooq,Al-Wabel, Mohammad I.,Lee, Sang Soo,Ok, Yong Sik Springer-Verlag 2018 Environmental geochemistry and health Vol.40 No.1

Effect of Corn Residue Biochar on Hydraulic Properties of Sandy Loam Soil

Avanthi Deshani Igalavithana,Sang Soo Lee,Yong Sik Ok 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Soil Microbial Community Abundance and Metal Immobilization in Contaminated Soils with Slow Pyrolyzed Biochars

( Avanthi Deshani Igalavithana ),( Sang Soo Lee ),( Yong Sik Ok ) 한국환경농학회 2016 한국환경농학회 학술대회집 Vol.2016 No.-

Slow pyrolyzed biochar is considered as a vital amendment in soil metal immobilization. However, its feasibility in multi-metal contaminated soils has not been studied well. This study evaluated the immobilization of Pb and As in two contaminated soils by slow pyrolyzed biochars at 500℃ derived from umbrella tree (Maesopsis eminii) wood bark (WB, pH 9.6), cocopeat (CP, pH 10.3) and palm kernel shell (PKS, pH 6.9). Also, biochar effects on microbial community and dehydrogenase activity (DHA) were evaluated. Biochar phosphorous contents were 485, 302, and 274 mg/kg respectively in WB, CP and PKS. The silicon content in WB, CP and PKS was 7604, 11590 and 10310 mg/kg respectively. Metal contaminated soils were collected from croplands nearby two mining sites (site-1 and site-2) in Korea. Soils were incubated with 5% (w/w) biochar at 25℃ and 70% water holding capacity for 45 days. After the incubation period metal existing geochemical fractions were assessed by sequential extractions. Fatty acid methyl ester analysis (FAME) was employed to assess the changes in microbial community. Exchangeable Pb was found in both site-1 and site-2 soils, but exchangeable As was detected only in site-2 soil. Addition of WB showed the highest reduction of Pb (site-1, 77.7%; site-2, 91.5%) in exchangeable fraction followed by that of CP (site-1, 67.1; site-2, 81.1%) and PKS (site-1, 9.1%; site-2, 20.0%); however, except PKS the remain two biochars increased the exchangeable As in site-2 soil (WB, 84.6%; CP, 14.8%). Alkalinity and high phosphorous content of biochars might be the main reasons in Pb immobilization or As mobilization. The silicon content in biochars is likely to be another influencing factor in increasing As mobility in the soils. The DHA was significantly increased by WB and CP in site-2 soil, but biochars were not increased the DHA in site-1 soil. The total FAME content in site-1 soil also was not increased by the biochars, while only PKS significantly increased the total FAME in site-2 soil. The low mobile matter content in biochar due to the relatively high pyrolysis temperature might not provide readily available C sources for microbial proliferation in soils. Biochar derived feedstock could be a critical parameter of biochar feasibility in soil health improvement in multi-metal contaminated soils. This study was supported by National Research Foundation of Korea (NRF; NRF- 2015R1A2A2A11001432).

토양효소 및 미생물특성에 기반한 도시 농업지역의 토양질 평가

아반티데샤니이갈라비피아나 ( Avanthi Deshani Igalavithana ),이상수 ( Sang Soo Lee ),옥용식 ( Yong Sik Ok ) 한국환경농학회 2016 한국환경농학회 학술대회집 Vol.2016 No.-

Urban agriculture has been recently highlighted with the increased importance of recreation in modern society; however, soil quality and public health may not be guaranteed because of continuous exposure to various pollutants from urban activities. The aim of the study was to evaluate the soil quality of urban agriculture by microbial parameters assessments. Field categorization was done based on applied fertilizer over 10 years, organic and inorganic fertilizers. The activities of soil enzymes including dehydrogenase, β-glucosidase, arylsulfatase, urease, alkaline and acid phosphatases were used as indicators of important microbial mediated functions and also the changes in soil chemical properties were measured. Fatty acid methyl ester analysis was applied to determine the soil microbial communities. Relatively higher microbial community richness and enzyme activities were found in the soils fertilized with organic fertilizers as compared to the soils fertilized with inorganic fertilizers. Principal component analysis explained the positive influence of organic fertilizers on the microbial communities. The application of organic fertilizers can be a better alternative to that of inorganic fertilizers for the long-term health and security of urban agriculture. This study was supported by “Cooperative Research Program for Agricultural Science & Technology Development (PJ010182042015)”, Rural Development Administration, Republic of Korea.

Characterization of bioenergy biochar and its utilization for metal/metalloid immobilization in contaminated soil

Yang, Xiao,Igalavithana, Avanthi D.,Oh, Sang-Eun,Nam, Hyungseok,Zhang, Ming,Wang, Chi-Hwa,Kwon, Eilhann E.,Tsang, Daniel C.W.,Ok, Yong Sik Elsevier 2018 The Science of the total environment Vol.640 No.-

<P><B>Abstract</B></P> <P>This study is a comparison of the effect of biochar produced by bioenergy systems, via the pyrolysis and gasification processes, on the immobilization of metals/metalloids in soil. Because the processes for these two techniques vary, the feedstocks undergo different heating regimens and, as a result, their respective char products exhibit different physico-chemical properties. Therefore, this study focuses on (1) the characterization of derivative biochar from the bioenergy system to understand their features and (2) an exploration of various biochar impacts on the mobility of As and Pb in contaminated soil. The results showed bioenergy biochars (BBCs) performed well in mitigating Pb extractability (1 M ammonium acetate) with a Pb immobilization >80%, but unfavorably mobilized the bioavailable As, likely because of electrostatic repulsion and ion exchange competition. The BBC surface functional group would chemically bond with the As and remain stable against the pH change. An increment in aromatic carbon would effectively enhance cation-π interaction for Pb immobilization. Nevertheless, an amendment with richer condensed structure and higher inorganic minerals (Ca<SUP>2+</SUP>, K<SUP>+</SUP>, Mg<SUP>2+</SUP>, and Na<SUP>+</SUP>) can lead to better performance in retaining Pb.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bioenergy system biochars (BBC) can be used to mitigate the bioavailability of metal(loid) pollutants in soil. </LI> <LI> The use of oxidizing gas in bioenergy technology can increase the surface functionality of the carbonaceous by-product. </LI> <LI> BBC characteristics are closely related to the immobilization performance of Pb and As in soil. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Mechanistic insights of 2,4-D sorption onto biochar: Influence of feedstock materials and biochar properties

Mandal, Sanchita,Sarkar, Binoy,Igalavithana, Avanthi Deshani,Ok, Yong Sik,Yang, Xiao,Lombi, Enzo,Bolan, Nanthi Elsevier Applied Science 2017 Bioresource technology Vol.246 No.-

<P><B>Abstract</B></P> <P>Objective of this study was to investigate the mechanisms of 2,4-Dichlorophynoxy acetic acid (2,4-D) sorption on biochar in aqueous solutions. Sorption isotherm, kinetics, and desorption experiments were performed to identify the role of biochars’ feedstock and production conditions on 2,4-D sorption. Biochars were prepared from various green wastes (tea, burcucumber, and hardwood) at two pyrolytic temperatures (400 and 700°C). The tea waste biochar produced at 700°C was further activated with steam under a controlled flow. The sorption of 2,4-D was strongly dependent on the biochar properties such as specific surface area, surface functional groups, and microporosity. The steam activated biochar produced from tea waste showed the highest (58.8mgg<SUP>−1</SUP>) 2,4-D sorption capacity, which was attributed to the high specific surface area (576m<SUP>2</SUP> g<SUP>−1</SUP>). The mechanism of 2,4-D removal from aqueous solution by biochar is mainly attributed to the formation of heterogeneous sorption sites due to the steam activation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Steam activated tea waste biochar sorbed the highest amount of 2,4-D. </LI> <LI> Steam activation increased biochar surface area and conserved oxygen-containing functional groups. </LI> <LI> 2,4-D desorption was lowest in steam activated biochar. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Removal of Hexavalent Chromium in Aqueous Solutions Using Different Biochars

Anushka Upamali Rajapaksha,Avanthi Deshani Igalavithana,Yong Sik Ok 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6