合成纳米锰钾矿去除废水中Cd2+的实验研究

Removal of Cd2+ by Synthetic nano-Cryptomelane from Sewage

摘要:

利用合成纳米锰钾矿去除模拟废水中Cd2+，实验研究了不同去除反应条件对废水中镉离子去除率的影响。实验结果表明：合成纳米锰钾矿对水溶液中Cd2+的去除，平衡时间约2 h；在Cd2+浓度为50 mg•L-1、溶液初始pH=6.50、反应温度25℃、处理剂粒径120～160目、投加量为2 g•L-1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，最大理论吸附量为120.5 mg•g-1。纳米锰钾矿对于Cd2+的去除是表面配位吸附、静电吸附、离子交换等三种模式共同作用的结果。

Abstract:

Removal rates of Cd2+ from sewage prepared in laboratory by synthetic nano-Cryptomelane under several factors were measured. The effluence of each factor on the rates was studied. The results showed that it took 2h before the removal process reached balance; when the concentration of Cd2+ was 50 mg•L-1, pH=6.50, 2 g•L-1 of the adsorbent dosage, 2 h of the adsorption time, the removal rate of Cd2+ was 90.6%. The adsorption isotherm was fitted by Langmuir model, and the theoretical maximum adsorption capacity was 120.5 mg•g-1 when the concentration of Cd2+ was less than 300 mg•L-1. The mechanisms of surface coordinate reactions, surface electrostatic adherences and ion exchanges are co-existing to remove Cd2+ from the solution treated by the synthetic nano-Cryptomelane.