合成纳米锰钾矿去除废水中Cd(Ⅱ)的实验研究

Removal of Cd(Ⅱ) by Synthetic Nano-cryptomelane from Sewage

利用合成纳米锰钾矿去除模拟废水中Cd(Ⅱ),研究不同去除反应条件对废水中镉离子去除率的影响.结果表明:合成纳米锰钾矿对水溶液中Cd2+的去除平衡时间约为2h;在Cd2+质量浓度为50mg·L-1、溶液初始pH=6.50、反应温度25℃、处理剂粒径96～120μm、每升模拟废水中投加2g合成纳米锰钾矿时,平衡后Cd2+去除率为90.6%.当Cd2+质量浓度不高于300 mg·L-1时,吸附等温线近似符合Langmuir模型,合成纳米锰钾矿最大理论吸附量为120.5mg·g-1.纳米锰钾矿对于Cd2+的去除是表面配位吸附、静电吸附、离子交换三种模式共同作用的结果.

Removal rates of Cd（II） from sewage prepared in laboratory by synthetic nano-cryptomelane under several factors were measured, and the influence of different factors on the rates was studied. Results show that it takes 2 hours for the removal process to reach balance. When the concentration of Cd^2＋ is 50 mg . L^-1 and the initial pH value is 6.50, the Cd^2＋ removal rate reaches to 90.6% by putting 2 g of nano-cryptomelane into the sewage for 2 hours at 25℃. The adsorption isotherm is fitted by Langmuir model, and the theoretical maximum adsorption capacity is 120.5 mg.g^-1 when the concentration of Cd^2＋ is less than 300 mg.L^-1. The Cd2＋ removal is realized by the co-work of the surface coordinate reactions, surface electrostatic adherences and ion exchanges of the synthetic nano-cryptomelane.