| In this paper, the adsorption effect of three kind of different clay minerals as a material to heavy metals was studied in different conditions. Compared with their adsorption difference, this article has discussed the different clay mineral material to the heavy metals adsorption characteristic, simultaneously has studied Cu2+ and under the Zn2+ coexistent condition, the natural bentonite to its adsorption effect and its the influence factor, and has compared if under the alone existence adsorption difference. And the adsorption quantity of different styles to heavy metals and the change of structure of bentonite fore-and-aft were studied in this paper. The related mechanism of adsorption to heavy metals on bentonite was discussed, as used clay mineral material handling heavy metals waste water well. At the same time, this experiment uses pillared bentonite processing using the hydroxyl-chromium to adsorb Cr (VI) for the first time. The adsorption effect of the hydroxy-aluminium and the hydroxyl-chromium bentonite to Cr (VI) has also discussed. And the X-ray diffraction characteristic change of the hydroxy-aluminium bentonite, the hydroxyl-chromium bentonite and the original bentonite was observed in this paper. Its adsorption mechanism has discussed initially. The results as follows:(1)The quantity of adsorption by expansibility clay mineral is not just decided by single CEC. Speaking of the adsorption characteristic, in the certain density scope, three kind of minerals to Cu2+, Zn2+, Cd2+ and the Pb2+ adsorption assumes the very good linear relation.(2)The adsorption of heavy metals on clay minerals surface is a rapid process, the maximal quantity of adsorption appears in ten minutes. The different granularity of clay minerals has different adsorption effects to heavy metals, but the quantity of adsorption is not changed by granularity of clay minerals all the while. The biggish pH value (about 6) of solution conduces to the adsorption of clay minerals to heavy metals, but the pH value can not be regulated too high considered to other factors of factual operation.(3)The adsorption of the coexistence of Cu2+ and Zn2+ on bentonite surface is also a rapid process, the maximal quantity of adsorption appears in ten minutes. The adsorption effect of different granularity bentonite to the coexistence of Cu2+ and Zn2+ was also consistent with their single exist. The biggish pH value of solution conduces to the adsorption of bentonite to them.(4)The adsorption of Cu2+ to the bentonite has a certain influence when Zn2+ existence, but in the bentonite adsorption intermixture the Zn2+ quantity is bigger than Cu2+. Compare with the influence of adsorbs Cu2+ to the bentonite by Zn2+, the influence of adsorbs Zn2+ to the bentonite by Cu2+ is bigger.(5)Under the same heavy metal molar density condition, the quantity of adsorption of bentonite slightly is higher than Zn2+ and Cd2+ to Cu2+, but the overall difference is not big. Namely the bentonite adsorption mainly determinated by heavy metal ion molar density in solution.(6)The adsorption of bentonite to the Cu2+ is the crystal level adsorption basically, but to Zn2+ and Cd2+ adsorption both existence surface adsorption and existence crystal level adsorption. The bentonite to Cu2+, Zn2+ and the Cd2+ crystal level adsorption size order is Cu2+ > Zn2+ > Cd2+. The bentonite level spacing enlarged when adsorbing Cu2+, it can be explained there had part of Cu2+ enter to the bentonite level.(7)Besides 200℃hot activation bentonite, the quantity of adsorption to Cu2+ is smaller than natural bentonite, such as 400℃, 600℃and 800℃hot activation bentonite. At the same time, the d001 values of different hot activation bentonites were lower than the natural bentonite, also its d001 diffraction peak obviously displacement to the high angle, the diffraction peak intensity also is lower than the natural bentonite.(8)The quantity of adsorption to Cu2+ of different acidification bentonites was lower than the natural bentonite. The diffraction peak intensity is lower than the natural bentonite, and the d001 values of different acidification bentonites were lower than the natural bentonite besides 20% sulfuric acidification bentonites.(9)The acid-sodium bentonite obviously surpasses the natural bentonite to the Cu2+ adsorption. The bentonite after the acid-sodium modification, its d001 diffraction peak obviously has the displacement, the diffraction peak intensity remarkably reduces, and the d001 value also falls by 1.5301 nm to 1.2571 nm.(10)The adsorption to Cr (VI) of the hydroxyl-chromium bentonite is better than the hydroxy-aluminiumcolumn bentonite and the original bentonite. The maximal quantity of adsorption on the hydroxyl-chromium bentonite appears in 30 minute. When the solution concentration is below 20 mg L-1, the quantity of adsorption to Cr (VI) on the hydroxyl-chromium bentonite is very good linear relation with solution Cr (VI), may use the dual first power regulation to indicate: y=0.0199x-0.017, R2=0.9908.(11)When the solution pH is in the scape of 4 to 10, the adsorption effect to Cr (VI) on hydroxyl-chromium bentonite is well.And when the solution pH is 12, the quantity of adsorption to Cr (VI) obviously reduces. The influence of solution pH of adsorption to Cr (VI) on the hydroxy-aluminium bentonite is small.
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