Arsenic(V) Removal in Wetland Filters Treating Drinking Water with Different Substrates and Plants.
Constructed wetlands are an attractive choice for removing arsenic (As) within water resources used for drinking water production. The role of substrate and vegetation in As removal processes is still poorly understood. In this study, gravel, zeolite (microporous aluminosilicate mineral), ceramsite (lightweight expanded clay aggregate) and manganese sand were tested as prospective substrates while aquaticJuncus effuses(Soft Rush or Common Rush) and terrestrialPteris vittataL. (Chinese Ladder Brake; known as As hyperaccumulator) were tested as potential wetland plants. Indoor batch adsorption experiments combined with outdoor column experiments were conducted to assess the As removal performances and process mechanisms. Batch adsorption results indicated that manganese sand had the maximum As(V) adsorption rate of 4.55 h-1and an adsorption capacity of 42.37 μg/g compared to the other three aggregates. The adsorption process followed the pseudo-first-order kinetic model and Freundlich isotherm equations better than other kinetic and isotherm models. Film-diffusion was the rate-limiting step. Mean adsorption energy calculation results indicated that chemical forces, particle diffusion and physical processes dominated As adsorption to manganese sand, zeolite and gravel, respectively. During the whole running period, manganese sand-packed wetland filters were associated with constantly 90% higher As(V) reduction of approximate 500 μg/L influent loads regardless if planted or not. The presence ofP. vittatacontributed to no more than 13.5% of the total As removal. In contrast,J. effuseswas associated with a 24% As removal efficiency.
Basin Water Environmental Research Institute, Changjiang River Scientific Research Institute, Wuhan 430010, China ; Key Lab of Basin Water Resource and Eco-environmental Science in Hubei Province, Changjiang River Scientific Research Institute, Wuhan 430010, China.
Min
M
Wu
Basin Water Environmental Research Institute, Changjiang River Scientific Research Institute, Wuhan 430010, China ; Key Lab of Basin Water Resource and Eco-environmental Science in Hubei Province, Changjiang River Scientific Research Institute, Wuhan 430010, China.
Qingyun
Q
Li
Ecological Remediation Technology Centre, Changjiang River Scientific Research Institute, Wuhan 430010, China ; Key Lab of Basin Water Resource and Eco-environmental Science in Hubei Province, Changjiang River Scientific Research Institute, Wuhan 430010, China.
Xianqiang
X
Tang
Basin Water Environmental Research Institute, Changjiang River Scientific Research Institute, Wuhan 430010, China ; Key Lab of Basin Water Resource and Eco-environmental Science in Hubei Province, Changjiang River Scientific Research Institute, Wuhan 430010, China.
Zhuo
Z
Huang
Basin Water Environmental Research Institute, Changjiang River Scientific Research Institute, Wuhan 430010, China ; Key Lab of Basin Water Resource and Eco-environmental Science in Hubei Province, Changjiang River Scientific Research Institute, Wuhan 430010, China.
Li
L
Lin
Civil Engineering Research Group, School of Computing, Science and Engineering, The University of Salford, Salford M5 4WT, England, UK.
Miklas
M
Scholz
Freundlich isotherm; Juncus effuses; Pteris vittata; adsorption; manganese sand