利用粉煤灰制备分子筛及对水体中六价铬的吸附研究

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0.3 g,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.

Adsorption of Hexavalent Chromium by Zeolite Synthesized of Fly Ash

Through wet method alkalinizing calcination , 4A Zeolite can be synthesized based on fly ash as main raw material.The effects of fly ash/alkali, calcination temperature and alcination time on 4A Zeolite were investigated .The results showed that 4A 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 4A 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 pH 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 .