孔隙结构和铝铁含量对水厂污泥吸磷的影响

Effects of Pore Structure and Al/Fe Content on Phosphorus Adsorption by Waterworks Sludge

为探究铝铁含量和孔隙结构对水厂污泥吸磷的作用,对水厂铁污泥和铝污泥的铝铁含量进行了检测,对其吸磷前后的孔隙结构和比表面积进行了分析,定量分析污泥吸磷前后微孔结构的变化。结果表明,水厂污泥主体孔径为介孔,直径4.0 nm左右的孔隙对污泥比表面积贡献最大。铁污泥和铝污泥BET模型比表面积分别为62.46、242.42 m2/g,铝、铁的质量分数分别为22.64%和11.96%,对磷的饱和吸附量分别为22.64、18.56 mg/g。吸附磷后2种污泥的比表面积都有下降,铝铁含量高比表面积小的污泥对磷的吸附量高于比表面积大铝铁含量低的污泥,这表明污泥吸附磷不仅受比表面积大小的影响,而且与其中的铝铁含量密切相关。

Aiming to research the influence of pore structure and aluminium and iron compound on P adsorption by waterworks sludge, aluminium and iron contents of iron sludge and aluminium sludge were monitored, the pore structure and specific surface area of the sludge, and the change of cellular structure before and after P adsorption were analysed. The results showed that, the pore size of waterworks sludge was mesoporous, pores with diameter 4.0 nm contributed most to the specific surface area of waterworks sludge. The BET model specific surface area of aluminium and iron sludge was 242.4 m2/g and 62.46 m2/g respectively, and the mass fraction of aluminium and iron was 22.64% and 11.96% respectively, the saturation adsorption capacity of P by was aluminium and iron sludge 22.64 and 18.56 mg/g, respectively. The specific surface area of aluminium and iron sludge was reduced after P adsorption. The sludge with high aluminium and iron content and a small specific surface area presented a greater P adsorption capacity than the sludge with low aluminium and iron content and a large specific surface area. The P adsorption on sludge not only depends on the specific surface area, but also related closely to the content of iron and aluminium.