铁锰氧化物在碱性条件下对镉的吸附特征研究

The adsorption of cadmium by goethite and manganite under alkaline conditions

实验研究了不同的pH值、初始离子浓度、矿物用量、温度以及时间等因素对针铁矿和软锰矿吸附镉的影响。结果表明:在pH值从酸性到近中性的范围内,两种氧化矿物对镉的吸附量增加较快,然后在碱性条件下吸附量保持着最大值;反应前后两种氧化矿物溶液的pH值均有不同程度的变化,其中针铁矿和软锰矿的临界pH值分别为8和6.5;两种矿物对镉的吸附在6 h左右达到了吸附平衡,吸附等温线都较好地符合Freundlich等温方程式;随着两种氧化物用量的增加,其吸附量也有增加;室温下,针铁矿和软锰矿对镉的吸附效果较好。

The adsorption of cadmium by goethite and manganite was experimentally studied.The adsorption quantity of cadmium by goethite and manganite increased with the increase of pH from acid to neutral and reached the maximum under the alkaline condition.After the adsorption of cadmium by goethite and manganite happened,the pH values of the solutions were changed,and the critical pH values were 8 for goethite and 6.5 for manganite.The adsorption balance time of goethite and manganite for cadmium was 6 hours.The adsorption isotherms were consistent with Freundlich isothermal equation.The adsorption effect of goethite and manganite for cadmium was ideal at the room temperature.