title: Treatment of arsenic in acid wastewater and river sediment by Fe@Fe2O3nanobunches: The effect of environmental conditions and reaction mechanism.
abstract: High concentration of arsenic in acid wastewater and polluted river sediment caused by metallurgical industry has presented a great environmental challenge for decades. Nanoscale zero valent iron (nZVI) can detoxify arsenic-bearing wastewater and groundwater, but the low adsorption capacity and rapid passivation restrict its large-scale application. This study proposed a highly efficient arsenic treatment nanotechnology, using the core-shell Fe@Fe2O3nanobunches (NBZI) for removal of arsenic in acid wastewater with cyclic stability and transformation of arsenic speciation in sediment. The adsorption capacity of As(III) by NBZI was 60 times as high as that of nanoscale zero valent iron (nZVI) at neutral pH. Characterization of the prepared materials after reaction revealed that the contents of As(III) and As(V) were 65% and 35% under aerobic conditions, respectively, which is the evidence of oxidation included in the reaction process apart from adsorption and co-precipitation. The presence of oxygen was proved to improve the adsorption ability of the prepared NBZI towards As(III) with the removal efficiency increasing from 68% to 92%. In order to further enhance the performance of NBZI-2 in the absence of oxygen, a new Fenton-Like system of NBZI/H2O2to remove arsenic under the anoxic condition was also proposed. Furthermore, the removal efficiency of arsenic in acid wastewater remained to be 78% after 9 times of cycling. Meanwhile, most of the mobile fraction of arsenic in river sediment was transformed into residues after NBZI treatment for 20 days. The reaction mechanism between NBZI and arsenic was discussed in detail at last, indicating great potential of NBZI for the treatment of arsenic in wastewater and sediment.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China. Electronic address: tanglin@hnu.edu.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Tang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China.
authors.forename: Haopeng
authors.initials: H
authors.lastname: Feng
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Tang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China. Electronic address: zgming@hnu.edu.cn.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zeng
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China.
authors.forename: Yaocheng
authors.initials: Y
authors.lastname: Deng
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China.
authors.forename: Jiajia
authors.initials: J
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China.
authors.forename: Yani
authors.initials: Y
authors.lastname: Liu
authors.affiliation: College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, China.
authors.forename: Yaoyu
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D045483:Rivers; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D001151:Arsenic; D005290:Ferric Compounds; D006861:Hydrogen Peroxide; D007501:Iron; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Adsorption; Arsenic treatment; Core-shell structure; Fe@Fe(2)O(3) nanobunches; Oxidation; Zero valent iron