利用粉煤灰制备分子筛及对水体中六价铬的吸附研究

Adsorption of Hexavalent Chromium by Zeolite Synthesized of Fly Ash

以粉煤灰为原料,采用湿法加碱煅烧法合成了4A分子筛,研究了粉煤灰与烧碱配比、煅烧温度、煅烧时间对合成4A分子筛的影响,结果表明粉煤灰与烧碱配比1.0∶0.8,煅烧温度700℃,煅烧时间1 h有利于4A分子筛的合成。利用合成的4A分子筛对水体中六价铬进行了吸附研究,实验确定的最佳吸附条件为:分子筛投加量为0.3g,溶液pH值为6~7,吸附时间为30 min,吸附温度为10~25℃。最佳吸附条件下分子筛对六价铬有较好的去除效果。吸附以物理吸附为主,符合Freundlich等温吸附式。同时对4A分子筛的再生性进行了研究,2次循环使用后其吸附能力仍能保持初次吸附能力的90.0%以上。

Through wet method alkalinizing calcination,4 A Zeolite can be synthesized based on fly ash as main raw material. The effects of fly ash/alkali,calcination temperature and alcination time on 4 A Zeolite were investigated. The results showed that 4 A zeolite had been synthesized under fly ash/alkali of 1. 0∶ 0. 8,calcination temperature of 700 ℃,calcination time of 1 h. At the same time,the removal efficiency of 4 A zeolite adsorbing hexavalent chromium in water was studied. The experiments showed that 4 A zeolite had higher removal efficiency for hexavalent chromiumion in water,when 4 A zeolite dosage was 0. 3 g,solution p H value was 6-7,adsorption time was 80 min and adsorption temperature was 10-25 ℃. The adsorption behavior of 4 A zeolite to sixvalent chromium accorded with Freundlich isotherm adsorption,mainly with physical absorption. Regeneration of 4 A zeolite was also studied,the results showed that,after 2 cycles,its adsorption capacity can still maintain more than 90% of the initial adsorption capacity.