热改性蛇纹石吸附剂除镉性能研究

采用对比的方式，分别对天然蛇纹石和经700℃改性的蛇纹石做了等温吸附实验，研究蛇纹石对重金属Cd2+的吸附性能，并探讨了影响吸附的因素和吸附机理。吸附剂用量、溶液的pH值对2种蛇纹石的吸附率均有较大影响。随着吸附剂用量的增加，天然蛇纹石和热改性蛇纹石对Cd2+的吸附率都逐渐增加，且吸附率都超过了60%。在同等吸附剂用量条件下，经700℃改性的蛇纹石的吸附能力要明显强于未改性的天然蛇纹石。当pH值为3～6时，2种蛇纹石对Cd2+的吸附量都随着pH值的增加而显著增大；当pH值为6～10时，对Cd2+的吸附量趋于稳定。两种蛇纹石均符合Freundlich方程，且拟合度较好，对重金属Cd2+有较强的吸附能力；经700℃改性的蛇纹石对Cd2+的饱和吸附量为8.19 mg/g，约等于天然蛇纹石饱和吸附量的2倍。

THE CHARACTERISTICS OF THERMAL-MODIFIED SERPENTINE`S ADSORPTION OF CADMIUM

An isothermal adsorption test was made between natural serpentine and thermal modified serpentine at 700 ℃ to remove the heavy ion Cd2+. This paper discusses the factors and mechanism of adsorption. Adsorption ratio depends largely on adsorbent quantity and solution pH value. Adsorption ratio rises up to over 60% with more adsorbent. Thermal modified serpentine is obviously better than natural serpentine in adsorption ability with the same amount of adsorbent. The adsorption capacity of both increases as pH value rises from 3 to 6, and tends to be stabilized as pH value is 6-10. Two kinds of serpentine are in accordance with Freundlich formula with a good fitting. The maximum adsorption quantity of thermal modified serpentine at 700 ℃ is 8.19 mg/g, approximately twice that of the natural serpentine.