The Research Of Adsorption Properties Of Attapulgite-based Carbon Composites

This paper used rape (or wheat) straw and attapulgite powder as raw materials, then mechanically sieved and mixed with phenolic resin. To mold to be samples with a certain dimension at a certain pressure and solidified after mixing by different dosing ration of raw materials. Then the samples were sintered in the atmosphere to obtain the attapulgite-based carbon composites. And it made use of these porous composite materials to adsorb the phenol and Cr(VI) wastewater. Explored in different conditions of dosage,shaking time,pH and different ratio of raw materials and the sintering temperature, the adsorption effect of Attapulgite-based carbon composite to the Cr(VI) and phenol, and found out the optimum conditions of adsorption.Using the composite materials of rape straw: attapulgite=1:2, sintering temperature is 900℃to adsorb Cr(VI). The results showed that: Cr(VI) can not be well adsorbed by attapulgite-based carbon composites in batch experiments. The removal rate is about 25%, and the adsorption capacity of Cr(VI) was only 0.185mg/g. But it was observed that the adsorption isotherms are well represented by both the Langmuir and Freundlich isotherm model. To all 20 kinds of composite materials on the adsorption of Cr(VI) found that, the greater proportion of rape straw in raw materials, the lower removal rate for the composite materials on the adsorption of Cr(VI). After the sintering temperature exceeded 700℃, the decline of removal rate is very obvious. When the rape straw: attapulgite=1:2, sintering temperature is 700℃, the composite materials on the removal rate of Cr(VI) is the highest, the removal rate could reach 95.6%.Using the composite materials of wheat straw: attapulgite=5:1, sintering temperature is 900℃to adsorb phenol. The results showed that: phenol can be well adsorbed by attapulgite-based carbon composites in batch experiments. And more in line with Freundlich isotherm model, the saturated adsorption capacity of phenol was 45.66mg/g, which indicates that the composite material has a strong adsorption of phenol. To all 20 kinds of composite materials on the adsorption of phenol found that, all materials have a good adsorption to phenol, the removal rate can reach more than 90%. However, there is still some differences, in general, the composite materials'adsorption efficiency of phenol is basically as the sintering temperature rise. when the sintering temperature reaches 900℃, all the composite material on the adsorption rate of phenol reached the maximum. And from the different proportions of each group of composite materials on the phenol removal rate can be roughly seen that, the greater proportion of wheat straw in raw materials, the higher removal rate for the composite materials on the adsorption of phenol.