预氧化法制备棉花秸秆活性炭去除印染废水中的铬(Ⅵ)

Removing of chromium(VI)from dyeing wastewater with cotton straw activated carbon prepared by pre-oxidation method

以新疆南疆棉花秸秆为原料,采用H_(2)SO_(4)预氧化和KOH活化制备活性炭,其Langmuir比表面积达到1 580.94 cm^(2)/g。采用静态吸附试验研究活性炭对印染废水中铬(Ⅵ)的吸附性能。结果表明:p H为2,Cr(Ⅵ)的初始质量浓度为0.5 mg/L,活性炭投加量为0.1 g,吸附时间为150 min时,Cr(Ⅵ)的吸附量为28 mg/g。Langmuir吸附等温线能更好地描述棉花秸秆活性炭吸附Cr(Ⅵ)的过程,R^(2)为0.988 24,说明棉花秸秆活性炭的表面Cr(Ⅵ)主要以单分子层形态吸附。活性炭对铬(Ⅵ)的吸附符合准二级动力学模型,R^(2)为0.950 25。

Activated carbon is prepared from cotton straw in southern Xinjiang using H_(2)SO_(4) pre-oxidation meth-od and KOH activation.The specific surface area of Langmuir reaches 1580.94 cm^(2)/g.Using static adsorption experiments,the adsorption performance of activated carbon on chromium(VI)in dyeing wastewater is ana-lyzed.The results show that when the pH is 2,the initial concentration of Cr(Ⅵ)is 0.5 mg/L,the mass of activat-ed carbon is 0.1 g,and the adsorption time is 150 min,the adsorption capacity of Cr(Ⅵ)is 28 mg/g.The Lang-muir adsorption isotherm can better describe the process of Cr(Ⅵ)adsorption by cotton straw activated car-bon with an R^(2) of 0.98824.It shows that Cr(Ⅵ)adsorbed on the surface of cotton straw activated carbon is mainly distributed in monolayer form.The kinetics show that the adsorption conforms to the quasi second or-der kinetic model with an R^(2) of 0.95025.