关键词: 板栗苞, 改性, 铬, 吸附

Abstract: The modified chestnut envelope split adsorption material was prepared by phosphoric acid modification with the chestnut envelope split as raw material and used for adsorbing Cr(Ⅵ). The effects of various parameters, including pH value, adsorption time, dose of adsorbent and temperature on the adsorption activity of Cr(Ⅵ) were investigated to determine the optimal conditions for Cr(Ⅵ) removal. Freundlich and Langmuir isotherms were used to fit the isothermal adsorption process. The results showed that when the mass concentration of Cr(VI) was 10 mg/L, the optimum adsorption conditions for the modified chestnut envelope split were pH value 4, adsorption time 2 h, modified chestnut envelope split dosage 0.2 g and temperature 45℃. Under these conditions, the adsorption rate of Cr(VI) on the modified chestnut envelope split could reach 99.33%. The adsorption equilibrium data agreed with the Langmuir equation, which indicated that the adsorption of Cr(VI) on the modified chestnut envelope split was monolayer adsorption. According to FT-IR characterization, there was no change in the group of modified chestnut envelope split after adsorption, indicating that the adsorption of Cr(VI) on modified chestnut envelope split was mainly physical adsorption. Through SEM characterization, it was found that the modified chestnut envelope split were smoother and had more space than the unmodified ones, indicating that the modification of phosphoric acid caused the impurities attached to the chestnut envelope split to be removed, the folds spread and the pore structure was more developed, which was beneficial to the adsorption of Cr(Ⅵ).

Key words: chestnut envelope split, modification, Cr(Ⅵ), adsorption