改性PAC吸附低温水中低质量浓度Cr(Ⅵ)研究

Research on adsorption of low concentration of Cr(Ⅵ) from low temperature source water by modified PAC

通过HNO3、Na OH氧化和负载食品级单宁酸等改性技术制备改性PAC,考察改性PAC对低温(2℃)水中低质量浓度Cr(Ⅵ)及Cr(Ⅲ)离子(0.500 mg/L)的去除性能,选择制备高效吸附低质量浓度CrⅥ)的PAC表面改性技术.试验结果表明,表面负载食品级单宁酸改性(TA-OC)为最佳改性方法,其比表面积、总孔容积和表面极性大小最佳,正交试验确定的TA-OC的最佳制备条件为:单宁酸质量浓度为15 mg/L,pH值为4,温度为40℃,时间为9 h.

The modification methods used in this work were HNO3/NaOH oxidation modifica-tion and immobilization of food-grade tannic acid.Through the analysis of the adsorption properties of modified carbons for the low concentration Cr（ VI）/Cr（Ⅲ） ion（0.500 mg/L） from low temperature water （2℃） , the optimal modification method was confirmed.Test re-sults showed that the carbon immobilized by tannic acid （ TA-OC） has the best adsorption properties and it is chosen as the optimal modified carbon.TA-OC has the best specific surface area, total pore volume and surface polarity.The variance analysis of orthogonal test indicated that the optimal preparation conditions of TA-OC were determined as food-grade tannic concentration of 15 mg/L, pH value of 4.0, temperature of 40 ℃ and the modified time of 9 h.