title: Effects of a manganese oxide-modified biochar composite on adsorption of arsenic in red soil.
abstract: The arsenic adsorption capacity of a manganese oxide-modified biochar composite (MBC), prepared by pyrolysis of a mixture of potassium permanganate and biochar, was investigated in red soil. Adsorption experiments using batch procedures were used to estimate the arsenic adsorption capacities of the absorbent materials. Adsorption and desorption isotherms, Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were used to characterise the prepared adsorbent materials, and a plausible mechanism for arsenic removal by MBC was proposed. Arsenic in red soil-MBC mixtures exhibited lower mobility than that in soils amended with pristine biochar. The improved removal performance of soil-MBC mixtures was attributed to a lower H/C ratio, higher O/C ratio, higher surface hydrophilicity, and higher surface sorption capacity, even though the impregnation of manganese oxide decreased the specific surface area of the biochar. Arsenic retention increased as the biochar content increased, mainly owing to an increase in soil pH. Several oxygenated functional groups, especially O-H, CO, Mn-O, and Si-O, participated in the adsorption process, and manganese oxides played a significant role in the oxidation of arsenic. This study highlights the potential of MBC as an absorbent to immobilise arsenic for use in contaminated land remediation in the red soils region.
authors: Centre for Research in Ecotoxicology and Environmental Remediation, Agro-Environmental Protection Institute, Tianjin 300191, China.
authors: Zhihong
authors: Z
authors: Yu
authors: Centre for Research in Ecotoxicology and Environmental Remediation, Agro-Environmental Protection Institute, Tianjin 300191, China.
authors: Li
authors: L
authors: Zhou
authors: Centre for Research in Ecotoxicology and Environmental Remediation, Agro-Environmental Protection Institute, Tianjin 300191, China.
authors: Yifan
authors: Y
authors: Huang
authors: Centre for Research in Ecotoxicology and Environmental Remediation, Agro-Environmental Protection Institute, Tianjin 300191, China. Electronic address: forestman1218@163.com.
authors: Zhengguo
authors: Z
authors: Song
authors: The New Zealand Institute for Plant and Food Research Limited, Private Bag 4704, Christchurch 8140, New Zealand.
authors: Weiwen
authors: W
authors: Qiu
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000737:chemistry* / Q000302:isolation & purification; D002606:Charcoal; D006863:Hydrogen-Ion Concentration; D017895:Manganese Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry* / Q000302:isolation & purification; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D017895:Manganese Compounds; D010087:Oxides; D012987:Soil; D012989:Soil Pollutants; C540010:biochar; D002606:Charcoal; C027424:manganese oxide; D001151:Arsenic
keywords: Adsorption; Arsenic; Manganese oxide-modified biochar; Oxidation; Red soil