Study Of The Preparation And Performance Of Chromium Removal Of Activated Carbon From Luffa Cylindrical Sponge

In this study, activated carbon was prepared from Luffa cylindrical sponge by chemicalactivation ZnCl₂and KOH. The effects of different factors on the properties of as-preparedactivated carbons were investigated by means of orthogonal test design. The optimal conditionby ZnCl₂activation were following: concentration of zinc chloride solution40%, activationtemperature450℃, activation time60min, and impregnating time12h. The as-preparedactivated carbon was porous and amorphous, which has high surface area of1020m²/g, and theyield, iodine and methylene blue adsorption value reached to29.07%,819.45mg/g and165.43mg/g, respectively.Using the same program, the optimal condition by KOH activation was following: KOH/Cvalue4, activation temperature800℃, activation time30min, and heating rate10℃/min. Theas-prepared activated carbon was porous and amorphous, which had high surface area of3545m2/g, and the yield, iodine and methylene blue adsorption value reached to15.63%,2926mg/gand528.58mg/g, respectively.The use of the activated carbon made from Luffa cylindrical sponge in the removal of Cr（VI）aqueous solutions was studied. The influences of the solution pH, time, initial Cr（VI）concentration, temperature and oscillation rate were investigated.The activated carbon dosage by ZnCl₂activation was1.0g/l, the optimal condition were pH2, time1h, initial Cr（VI） concentration50mg/L, temperature20℃and oscillation rate125r/min, respectively. On this condition, the values of Cr（VI） removal, total chromium removal,adsorption capacity of the activated carbon were95.98%、86.87%and43.44mg/g, respectively.The activated carbon dosage by KOH activation was0.8g/L, the optimal condition were pH2,time0.5h, initial Cr（VI） concentration60mg/L, temperature20℃and oscillation rate125r/min, respectively. On this condition, the values of Cr（VI） removal, total chromium removal,adsorption capacity of the activated carbon were99.47%,80.28%and60.21mg/g, respectively.Also the pseudo-second-order equations provided the greatest accuracy for kinetic date forthe activated carbon by ZnCl₂and KOH activation, which the correlation coefficient was1,respectively. The Freundlich isotherm models were the closes fit for equilibrium date.And thecharacteristic coefficient of n were:1<n <10, indicating these two activated carbon adsorptionof total chromium belonged to preferential adsorption.The adsorption mechanism studies hadshow that activated carbon adsorption chromium wer both physical adsorption and chemisorptions, also redox, and the adsorption ability of [HCrO4]-was better than Cr（Ш）. SEMobserved after adsorption of the activated carbons presented a lot of shiny material; thechromium on activated carbons surface could be determined by EDAX. The redox role-OH, C=C stretching and ring vibration area groups exposed by FT-IR.