Effects of phosphate and citric acid on Pb adsorption by red soil colloids
Effects of phosphate and citric acid on Pb adsorption by red soil colloids
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DOI：
10.1002/ep.12301
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发表时间：
2016-07
影响因子：
2.8
通讯作者：
J. Zuo;Q. Fu;Xiao-juan Su;Yonghong Liu;Jun Zhu;Hongqing Hu;Youjun Deng
中科院分区：
文献类型：
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作者：
J. Zuo;Q. Fu;Xiao-juan Su;Yonghong Liu;Jun Zhu;Hongqing Hu;Youjun Deng
根际土壤中含有丰富的有机酸，可能干扰磷与重金属的反应。通过静态平衡实验、Zeta电位和X射线衍射（XRD）分析，研究了柠檬酸（Cit）存在下磷酸盐对红壤胶体（Ultisol）吸附Pb 2+的影响。结果表明，在不同浓度的磷酸盐（P）存在下，Pb 2+的吸附峰状曲线均上移甚至消失。用Langmuir方程拟合Pb 2+的等温吸附曲线，各处理的吸附反应常数（K）、最大吸附量（Xm）均为1.0 mmol/L P > 1.0 mmol/L P + 0.5 mmol/L Cit > 0.5 mmol/L Cit。在柠檬酸的影响下，当pH为0.5 mmol/L Cit > 1 mmol/L P时，Pb 2+的吸附量增加，这与P对Pb 2+的吸附量不同，表明P对Pb 2+的吸附不仅是一种电吸附。而在其它处理中没有检测到磷酸铅峰。添加磷酸盐的红壤胶体对Pb 2+的吸附机理主要为类磷氯铅矿的形成。而0.5mmol/L的Cit则抑制磷氯铅矿的形成。© 2016美国化学工程师学会环境规划，35：969-974，2016
There are abundant organic acids in rhizospheric soil, which may interfere in the reaction between phosphate and heavy metals. Effects of phosphate on Pb2+ adsorption by red soil colloids(Ultisol) were studied in the presence of citric acid (Cit) through batch equilibrium experiments, Zeta potential and X‐ray diffraction (XRD) analyses. Results showed that in the presence of different concentrations of phosphate (P), the peak‐like curves of Pb2+ sorption was moved up even disappeared. When the Langmuir equation was used to model isothermal adsorption curve of Pb2+, the adsorption reaction constant (K), the maximum adsorption quantity (Xm) of several treatments were both in a decreasing order of 1.0 mmol/L P > 1.0 mmol/L P + 0.5 mmol/L Cit > 0.5 mmol/L Cit. Under the influence of citric acid, the Pb2+ adsorption amount increased at pH 0.5 mmol/L Cit > 1 mmol/L P, which were different from that of the Pb2+ adsorption amount, suggesting that the adsorption of Pb2+ was not only an electrical adsorption in the presence of P. XRD patterns proved that occurrence of pyromorphite for the treatment with 1.0 mmol/L P addition, whereas no lead phosphate peak was detected in other treatments. The mechanism of Pb2+ adsorbed in red soil colloids with addition of phosphate was primary formation of pyromorphite‐like compounds. However, 0.5 mmol/L Cit inhibited the formation of pyromorphite. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 969–974, 2016