Effect of Ca2+-ions on the absorption of Pb2+, Cu2+, Cd2+ and Zn2+ by humic substances

Distribution coefficients for the sorption of Pb²⁺, Cu²⁺, Cd²⁺ and Zn²⁺ by peat were determined as a function of the Ca²⁺-content of peat as well as of the Ca²⁺-concentration in the solution. The amount of heavy metal ions taken up was measured for Cu²⁺, Cd²⁺ and Zn²⁺ by atomic absorption spectrometry and for Pb²⁺ by using Pb-212 as a radioactive tracer.The results show that the distribution coefficients of the heavy metal ions increase, if one increases the initial ratio of the $\text{Ca}{}^{\mathrm{2+}}\text{H}{}^{\mathrm{+}}\text{-}\text{ions}$ in the peat phase. The distribution coefficients for the heavy metal ions decrease, however, if - at constant initial Ca²⁺-content of the peat - the Ca²⁺-concentration of the solution is increased.     

沸石负载淀粉对Pb2+、Cu2+和Ni2+的吸附性能

将淀粉负载到沸石表面得到新型重金属离子复合吸附剂ZLS。分别从沸石与淀粉质量比、吸附温度、吸附时间、pH与重金属初始浓度不同方面考察了复合吸附剂ZLS吸附 Pb²⁺、Cu²⁺、Ni²⁺的影响。实验结果表明:当沸石与淀粉质量比为10:1,pH为6,吸附温度在30℃时,复合型吸附剂ZLS对Pb²⁺、Cu²⁺和Ni²⁺ 3种重金属离子的吸附效果最好;吸附动力学研究发现,ZLS对Pb²⁺、Cu²⁺和Ni²⁺的吸附行为均符合准二级动力学以及颗粒内部扩散模型;等温吸附数据符合Freundlich模型,吸附状态属于多层吸附。     

矸石基X型分子筛对水中Co2+、Cu2+、Cd2+和Cr3+的去除

以煤矸石为原料,采用碱熔后水热合成法制备X型分子筛并进行XRD、SEM、BET和Zeta电位分析。研究其对水中Co2+、Cu2+、Cd2+和Cr3+4种离子的吸附性能,包括吸附等温线、吸附动力学以及初始金属离子浓度、pH值对吸附性能的影响。所合成的矸石基X型分子筛的BET比表面积为676.02 m2/g,微孔孔容为0.263 cm3/g。吸附实验表明,矸石基X型分子筛能有效去除上述4种离子,同时实现煤矸石的资源化和金属离子的去除。4种离子的平衡吸附量均随初始浓度的增大而增大,相同条件下平衡吸附量的大小顺序为Cd2+>Cr3+>Cu2+>Co2+。准二级动力学模型能很好地描述4种离子的吸附动力行为。Langmuir模型对Co2+、Cu2+和Cd2+吸附的拟合较Freundlich模型高,说明其主要表现为物理吸附过程。4种离子的吸附速率均由液膜扩散和颗粒内扩散共同控制。