Comparison of U(VI) adsorption onto nanoscale zero-valent iron and red soil in the presence of U(VI)-CO3/Ca-U(VI)-CO3 complexes.
The influence of U(VI)-CO3 and Ca-U(VI)-CO3 complexes on U(VI) adsorption onto red soil and nanoscale zero-valent iron (NZVI) was investigated using batch adsorption and fixed-bed column experiments to simulate the feasibility of NZVI as the reactive medium in permeable- reactive barriers (PRB) for in situ remediation of uranium-contaminated red soils. The adsorption capacity (qe) and distribution constant (Kd) of NZVI and red soil decreased with increasing pH, dissolved carbonate and calcium concentrations, but the qe and Kd values of NZVI were 5-10 times higher than those of red soil. The breakthrough pore volume (PV) values increased with the decrease of pH, dissolved carbonate and calcium concentration; however, the breakthrough PV values of the PRB column filled with 5% NZVI were 2.0-3.5 times higher than the 100% red soil column. The U(VI)-CO3 complexes adsorbed onto the surface of red soil/NZVI (≡SOH) to form SO-UO2CO3(-) or SO-UO2 (CO3)2(3-). XPS and XRD analysis further confirmed the reduction of U(VI) to U(IV) and the formation of FeOOH on NZVI surfaces. The findings of this study are significant to the remediation of uranium-contaminated red soils and the consideration of practical U(VI) species in the natural environment.
Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Nanchang 330013, PR China; State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang 330013, PR China; Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013, PR China.
Zhibin
Z
Zhang
State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang 330013, PR China.
Jun
J
Liu
Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Nanchang 330013, PR China; State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang 330013, PR China; Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013, PR China. Electronic address: xhcao@ecit.cn.
Xiaohong
X
Cao
Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013, PR China.
Xuanping
X
Luo
Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Nanchang 330013, PR China; State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang 330013, PR China; Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013, PR China.
Rong
R
Hua
Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Nanchang 330013, PR China; State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang 330013, PR China; Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013, PR China.
Yan
Y
Liu
Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013, PR China.
Xiaofeng
X
Yu
Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013, PR China.
Likai
L
He
Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Nanchang 330013, PR China; State Key Laboratory Breeding Base of Nuclear Resources and Environment (East China Institute of Technology), Ministry of Education, Nanchang 330013, PR China; Chemistry, Biological and Materials Sciences Department, East China Institute of Technology, Nanchang 330013, PR China. Electronic address: walton_liu@163.com.
Yunhai
Y
Liu
Mechanism; Nanoscale zero- valent iron; Permeable-reactive Barriers; Red soil; U(VI)–CO(3)/Ca–U(VI)–CO(3) complexes