[Adsorption behavior of exogenous thorium on soil contaminated by rare earth industries].
The adsorption behavior of exogenous thorium on soil was studied to evaluate the contaminated risk on soil. The adsorption capacity, equilibrium time, distribution coefficient and desorption ability were investigated by the experiments of static adsorption. The strong adsorption ability of exogenous thorium on soil samples was observed by high adsorption ratio (> 92%) and low desorption ratio (< 5%) in equilibrium, and the biggest distribution coefficient was over 10(4). The adsorption capacity and equilibrium time were related to soil properties. According to the results of adsorption, Freundlich equation (r > or = 0.9167) and Elovich equation (R2 > or = 0.8980) were primely fit for describing the thermodynamics and kinetics of the adsorption of exogenous thorium on soil samples, respectively, which indicated that the adsorption was belonged to the nonlinear adsorption, and was affected by the diffusion of thorium on soil surface and in mineral interbed. Sequential extraction procedure was employed to evaluate the bound fractions of exogenous thorium adsorbed on soil samples. Based on the extracted results of thorium fractions, exogenous thorium was presented in the labile nonresidual fractions (over 58%) at the low initial concentration (10(-7) - 10(-6) mol x L(-1)), and nonresidual fractions enhanced with the increase of the initial amount, meanwhile more exogenous throium was transferred to the stable residual fractions.
Guo
Peng-ran
PR
School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China. guopengran@gmail.com
Jia
Xiao-yu
XY
Duan
Tai-cheng
TC
Qiu
Rong-liang
RL
Chen
Hang-ting
HT
D000327:Adsorption; D007220:Industrial Waste / Q000032:analysis*; D008674:Metals, Rare Earth; D008906:Mining; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000737:chemistry* / Q000378:metabolism; D013910:Thorium / Q000737:chemistry* / Q000378:metabolism
D007220:Industrial Waste; D008674:Metals, Rare Earth; D012987:Soil; D012989:Soil Pollutants; D013910:Thorium