三价铁改性活性炭对水中微量砷的吸附特性

研究了三价铁改性对不同活性炭(颗粒和粉末)对水中砷的吸附特性的影响。结果表明,三价铁改性有效提高了活性炭对不同形态砷的吸附性能。其中,对于2种活性炭,As(Ⅲ)和As(Ⅴ)的最佳铁离子改性浓度分别为0.1和0.05 mol/L。此时,通过Langmuir等温线方程拟合得到:粉末和颗粒活性炭对As(Ⅲ)的最大吸附量qm分别为2.38 mg/g和9.39 mg/g;而对As(Ⅴ)的qm分别为5.12 mg/g和2.32 mg/g。此外,当溶液的pH从3升高到9的过程中,吸附量先增加后有所下降,当pH 为7时,改性前后的活性炭对砷的吸附量达到最高。

Adsorption properties of low concentration arsenic in water by modified activated carbon with ferric iron

In this study, the effect of ferric modification on the adsorption properties of different forms of activated carbon (granular and powdered) was investigated. The results showed that the adsorption capacity of activated carbon for arsenate with different speciations was effectively improved with ferric modification. For both forms of activated carbons, the optimal ferric concentrations for modification were 0.1 mol/L for As(Ⅲ) and 0.05 mol/L for As(Ⅴ). At the same time, Langmuir isotherm equation fitting results indicated that the maximum adsorption capacities (qm) were 2.38 mg/g and 9.39 mg/g for As(Ⅲ) and 2.32 mg/g and 5.12 mg/g for As(Ⅴ) with powdered activated carbon (PAC) and granular activated carbon (GAC), respectively. In addition, when the solution pH increased from 3 to 9, the adsorption capacity increased initially and then decreased slightly later; the maximum adsorption capacity can be achieved at pH of 7.