巯基改性硅胶吸附汞性能的研究

Study on sulfur-hydrogen modified silica gel for Hg^(2+) adsorption

探讨制备活性硅胶,并与氯丙基三氯硅烷改性得氯丙基三氯硅烷改性硅胶(CP-硅胶),后再用硫氢化钠进行巯基化得到巯基改性硅胶(SH-硅胶)。实验发现CP-硅胶、SH-硅胶总有机碳含量分别为8.98%(wt,质量分数,下同)、7.03%,SH-硅胶含硫量为4.99%,巯基转化率约80%。由SH-硅胶对硝酸汞(Hg^(2+))吸附实验发现,SH-硅胶吸附平衡需12h,对Hg^(2+)的去除率达到95%以上,饱和吸附量为230mg/g。吸附平衡时间随Hg^(2+)浓度增大而变长,溶液pH值越高(pH≤7),对Hg^(2+)去除率愈高。

Discussed the preparation of active silica gel,and then reacted with chloropropyl trichlorosilane to get chloropropthyl-propyl trichlorosilane modified silica gel（CP-silica gel）.Then reacted with NaHS to get sulfur-hydrogen modified silica gel（SH-silica gel）.It was showed that the TOC contents of CP-silica gel and SH-silica gel were 8.98%,7.03%,repectively,the sulfur content of SH-silica gel was 4.99%.The conversion rate of sulfur was about 80%.It was found that the adsorption of mercury nitrate by SH-silica gel reached the adsorption equilibrium after 12 hours,and Hg^2＋adsorption efficiency can above 95%,the saturated adsorption capacity was 230mg/g.Increased mercury nitrate concentration and adsorption equilibrium time became longer.Mercury nitrate solution concentration was higher,the higher the pH value（pH≤7）of solution,the higher the Hg^2＋removal rate.