Study On The Technology Of Adsorbing Heavy Metal By Modified Attapulgite

Nowadays, the serious pollution caused by heavy mental has become one of the urgent environmental issues that need to be solved. The State Council approved<Comprehensive Control of Heavy Mental Pollution Project> as the first specific project of the 12th Five Years Plan, which reflects the huge attention that the central government has paid to the problem. Under this circumstance, studying the technology of absorbing heavy mental is of great realistic meanings.This paper chooses attagulgite as the study object and focuses on its absorption properties of heavy mental. The experimental method included three steps:first, attagulgite was modified by hydrochloric acid and high temperature; second, the modified attagulgite was used to absorb heavy mental; last but not the least, the attagulgite that had done absorbing was regenerated by hydrochloric acid. After doing lots of experiments, optimum technology was found as follows:1. Attapulgite’s surface area can be increased through hydrochloric acid soak and calcination. When the concentration of hydrochloric acid is 0.6mol/l, The ratio of attapulgite to hydrochloric acid is 20:(g/l), the soak time is 1.3h, attapulgite’s surface area is the largest. When the calcination temperature is 500℃, the calcination time is 2.5h, attapulgite’s surface area is the largest.2. Modified attapulgite can absorb heavy mental from waste water. When absorbing time 3.5h,pH is 4.0, the proportion of Attapulgite and waste water is 20:100 (g/ml),the absorbing temperature is 55℃, the absorbing effect is better, the absorbing effects of Cr3+、Cu2+、Cd2+　are 76.73%、80.31%、 48.32%。 When absorbing time is 1h, pH is 3.0, the ratio of attapulgite to waste water is 15:100 (g/ml), the absorbing temperature is 40℃, the effect of absorbing Pb2+ is better, the absorbing effect is 100% almost。3. The attapulgite that has done absorbing can be regenerated by being immersed in hydrochloric acid. When the concentration of hydrochloric acid is 1 mol/1, the resolving time is 15min, the resolving temperture is 25℃, the ratio of Attapulgite to hydrochloric acid is 1:20 (g/ml), the effect of resolving Cd2+、Pb2+ is better, the effect of resolving Cd2+、Pb2+ can reach 97%、70%.