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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p H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p H值为3~6时,2种蛇纹石对Cd2+的吸附量都随着p H值的增加而显著增大;当p H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。
By means of comparison, the adsorption experiments of natural serpentine and serpentine modified at 700 ℃ were carried out respectively to study the adsorption properties of serpentine to heavy metal Cd2 +, and to explore the factors affecting the adsorption and adsorption mechanism. The amount of adsorbent and the p H value of the solution have a significant effect on the adsorption rates of the two serpentines. With the increase of the amount of adsorbent, the adsorption rate of Cd2 + by natural serpentine and heat-modified serpentine increased gradually, and the adsorption rates exceeded 60%. Under the same adsorbent dosage, the adsorption capacity of serpentine modified by 700 ℃ is obviously higher than that of unmodified natural serpentine. When p H value is 3 ~ 6, the adsorption amount of Cd2 + by two kinds of serpentine increases with the increase of p H value. When p H value is 6 ~ 10, the adsorption amount of Cd2 + tends to stable. The two serpentines are in accordance with the Freundlich equation, and have a good fit, and have a strong adsorption capacity for heavy metal Cd2 +. The saturated adsorption capacity of the serpentine modified by 700 ℃ to Cd2 + is 8.19 mg / g, which is approximately equal to Natural serpentine saturated adsorption capacity of 2 times.