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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 effects of different pH, initial ion concentration, mineral content, temperature and time on the adsorption of cadmium on goethite and pyrolusite were studied experimentally. The results showed that in the range of pH value from acid to near neutral, the amount of cadmium adsorbed by two kinds of oxidized minerals increased rapidly, and then the amount of adsorption remained the maximum under alkaline conditions. Before and after the reaction, two kinds of oxidized mineral solution the pH value of the two minerals varied with different degrees. The critical pH values of goethite and pyrolusite were 8 and 6.5, respectively. The adsorption of cadmium by two minerals reached the adsorption equilibrium at about 6 h, and the adsorption isotherms all fit well Freundlich equation of isotherm; with the increase of the amount of two oxides, the amount of adsorption also increased; goethite and pyrolusite adsorbed cadmium better at room temperature.