天然和巯基改性沸石吸附水溶液中重金属Hg^2＋的特征研究

为了提高沸石对汞的吸附性，利用半胱胺盐酸盐对天然斜发沸石进行改性，制得巯基改性沸石。研究了吸附剂用量、pH值、温度、Hg^2＋浓度和吸附时间对沸石和巯基改性沸石吸附Hg^2＋的影响，并进一步研究了吸附机理。结果表明，巯基改性沸石吸附Hg^2＋受pH值、温度的影响较小，吸附机制主要是沸石表面的硫与Hg^2＋的化学反应。而天然沸石对Hg^2＋的吸附主要是离子交换作用，受温度、pH值等的影响较大，随温度的升高吸附量下降。整个吸附过程以较快的速度进行。天然沸石在吸附时间为1h、巯基改性沸石在0．5h时基本达到吸附平衡。吸附条件试验和Langmuir等温吸附模型都表明，巯基改性沸石对Hg^2＋的吸附能力得到了很大的提高，吸附容量由8．06mg／g提高到19．88mg／g，提高了146．65％。

Study on characterization of mercury sorption by natural and thiol modified zeolites

This work, using cysteamine hydrochloride to modify natural clinoptilolite zeolites, results in great enhancement of absorption capacity. The effects of absorber dosage, pH values, temperature, adsorption time and Hg^2＋ concentration on Hg^2＋ adsorption and adsorption mechanism are researched. The result shows that the mercury retention by the modified zeolite is attributed to the metal-chelating S functionality, while the one by the natural zeolite is cation exchange. The pH and temperature factors that have slightly effect on the modified zeolite adsorption could significantly affect the natural zeolite; the higher the temperature is, the lower the sorption rate is. Within a high rate of the adsorption process, the modified zeolite takes 0.5 h to reach the adsorption equilibrium, while the natural zeolite takes 1 h. The Langmuir isotherm model and the adsorption conditions experiment both indicate that the modification has greatly enhanced the adsorption capacity for Hg^2＋ , the maximum capacity is increased by 146.65% , from 8. 06 mg/g to 19.88 mg/g Hg.