Preparation And Adsorption Performance Of Activated Carbon Modified By KMnO₄

Activated carbon is an efficient adsorbent. Because of its fast adsorption rate,high adsorption capacity and easy regeneration, it has good adsorption effect of inorganic and organic matters. Pb²⁺,Cr⁶⁺ is able to accumulate in animals and plants easily,and with high toxicity,now it has been identified as a carcinogen.Dye wastewater is a kind of industrial wastewater with complex components, high concentration of organic compounds is difficult to be degraded.The test used the activated carbon which was modified by potassium permanganate to adsorb it,the adsorption characteristics of Pb²⁺、Cr⁶⁺ 、methylene blue and methyl violet has been studied.The modified activated carbon was characterized by scanning electron microscopy（SEM）, Fourier transform infrared spectrometer（FT-IR）, and N₂ adsorption/desorption tests.The effects of various parameters such as p H, contact time, sorbent dosage, temperature,and initial concentration on the adsorption of Pb²⁺、Cr⁶⁺、methylene blue and methyl violet were determined. Studies have shown:（1）At room temperature（25 ℃）,when the p H = 2,contact time was 4 h,the dosage of modified carbon is 50 mg, Cr⁶⁺ concentration of 100 μg ?L^-1, the adsorption capacity of activated carbon modified with KMnO₄ for heavy metal ions Cr⁶⁺ from aqueous solution was the best, AC3 adsorption rates were 91.23%.The modified activated carbon on Cr⁶⁺may be fitted in with Langmuir equation.（2）At room temperature（25 ℃）,when the p H = 3, contact time was 4 h,the dosage of modified carbon is 50 mg,Pb²⁺concentration of 100 mg ? L^-1, the adsorption capacity of activated carbon modified with KMnO₄ for heavy metal ions Pb²⁺from aqueous solution was the best, AC3 adsorption rates were 93.5%.The modified activated carbon on Pb²⁺may be fitted in with Langmuir equation.（3）At room temperature（25 ℃）,when the p H = 7, contact time was 4 h,the dosage of modified carbon is 50 mg, methylene blue concentration of 100 mg ? L^-1, the adsorption capacity of activated carbon modified with KMnO₄ for methylene blue from aqueous solution was the best, AC3 adsorption rates were 93.56%.（4）At room temperature（25 ℃）,when the p H = 9, contact time was 4 h,the dosage of modified carbon is 50 mg, methyl violet concentration of 100 mg ? L^-1, the adsorption capacity of activated carbon modified with KMnO₄ for methyl violet from aqueous solution was the best, AC3 adsorption rates were95.87%.The modified activated carbon on methylene blue and methyl violet may be fitted in with Langmuir equation.