title: In situ immobilization of cadmium in soil by stabilized biochar-supported iron phosphate nanoparticles.
abstract: The potential for nanoscale phosphate amendments to remediate heavy metal contamination has been widely investigated, but the strong tendency of nanoparticles to form aggregates limits the application of this technique in soil. This study synthesized a composite of biochar-supported iron phosphate nanoparticle (BC@Fe3(PO4)2) stabilized by a sodium carboxymethyl cellulose to improve the stability and mobility of the amendment in soil. The sedimentation test and column test demonstrated that BC@Fe3(PO4)2 exhibited better stability and mobility than iron phosphate nanoparticles. After 28 days of simulated in situ remediation, the immobilization efficiency of Cd was 60.2 %, and the physiological-based extraction test bioaccessibility was reduced by 53.9 %. The results of sequential extraction procedures indicated that the transformation from exchangeable (EX) Cd to organic matter (OM) and residue (RS) was responsible for the decrease in Cd leachability in soil. Accordingly, the pot test indicated that Cd uptake by cabbage mustard was suppressed by 86.8 %. Compared to tests using iron phosphate nanoparticles, the addition of BC@Fe3(PO4)2 to soil could reduce the Fe uptake of cabbage mustard. Overall, this study revealed that BC@Fe3(PO4)2 could provide effective in situ remediation of Cd in soil.
authors.affiliation: School of Chemistry and Environment, South China Normal University, Guangzhou, 510006, China.|Guangdong Technology Research Center for Ecological Management and Remediation of Water System, Guangzhou, 510006, China.
authors.forename: Yanzhe
authors.initials: Y
authors.lastname: Xu
authors.affiliation: School of Chemistry and Environment, South China Normal University, Guangzhou, 510006, China. sunmoon124@163.com.|Guangdong Technology Research Center for Ecological Management and Remediation of Water System, Guangzhou, 510006, China. sunmoon124@163.com.
authors.forename: Zhanqiang
authors.initials: Z
authors.lastname: Fang
authors.affiliation: Guangdong Technology Research Center for Ecological Management and Remediation of Water System, Guangzhou, 510006, China. etsang@ied.edu.hk.|Department of Science and Environmental Studies, The Hong Kong Institute of Education, Hong Kong, 00852, China. etsang@ied.edu.hk.
authors.forename: Eric Pokeung
authors.initials: EP
authors.lastname: Tsang
mesh_terms: D002104:Cadmium / Q000737:chemistry*; D002266:Carboxymethylcellulose Sodium; D002606:Charcoal / Q000737:chemistry*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007501:Iron / Q000737:chemistry; D019216:Metals, Heavy / Q000737:chemistry; D009149:Mustard Plant; D053758:Nanoparticles / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D010710:Phosphates; D012987:Soil; D012989:Soil Pollutants; C540010:biochar; D002104:Cadmium; D002606:Charcoal; D007501:Iron; D002266:Carboxymethylcellulose Sodium
keywords: Biochar; Cd-polluted soil; In situ remediation; Iron phosphate; Mobility