铁盐改性砂制备及其吸附Zn~(2+)的性能研究

通过改变石英砂表面的物理化学性质,提高石英砂的吸附效率,考察其对废水中的Zn~(2+)去除效果.以石英砂为载体,分别用反复高温加热法和反复碱性沉积法制备了三氯化铁改性砂、硝酸铁改性砂,测定2种方法制备的铁盐改性砂的表面含铁量、铁盐的酸稳定性及比表面积,并比较2种铁盐改性砂对Zn~(2+)的吸附效果.结果表明,三氯化铁改性砂、硝酸铁改性砂的比表面积分别为2.468、4.247 m~2/g,比石英砂比表面积分别提高6.910、12.612倍;在pH为中性条件下,石英砂对Zn~(2+)去除率为43%左右,三氯化铁改性砂对Zn~(2+)去除率达到70%左右,硝酸铁改性砂对Zn~(2+)去除率达到85%左右,表明铁盐改性砂对Zn~(2+)去除能力比石英砂有很大提高;铁盐改性砂对Zn~(2+)的吸附有一定容量,表面的活性中心越多,吸附能力越大;铁盐改性砂对Zn~(2+)的去除率随着pH的升高而增加,当pH>8.5时,Zn~(2+)去除率可达90%左右.

Preparztion of ferric salt modified sands for Zn~(2+) adsorption

Ferric salt modified sand was prepared with quartz sand as a carrier and ferric salt coating by the two methods of repeat high-temperature process and repeat alkaline deposition process. The iron content, acid stability, specific surface area of two ferric salt modified sands were detected, and their Zn~(2+) adsorption capacity in different conditions were also described in this paper. The results showed that the specific surface area of ferric chloride and ferric nitrate modified sands were 2. 468 m~2/g and 4. 247 m~2/g respectively, which were improved 6. 910 and 12. 612 times than that of raw quartz sand. The larger specific surface area correlated higher Zn~(2+) removal efficiency, in the neutral pH condition, 85% and and over 70% of Zn~(2+) was removal by ferric nitrate modified sand and ferric chloride modified sand, much higher than that of raw quartz sand. The adsorption capability of ferric salt modified sand for Zn~(2+) was influenced by many factors. The more the surface active centers are, the higher the adsorption capability is.Moreover, the removal efficiency was enhanced with the increasing of pH level. More than 900/00 of Zn~(2+) was removed with pH of 8.5 or above.