红色黏土对磷的吸附性能及其机理初探

Phosphorus Adsorption of Red Clay and Its Mechanism

研究了采自江西鹰潭和江苏宜兴2地荒地亚层(20～40 cm)11种红色黏土的理化性质,比较了其对2种不同质量浓度(35和50 mg.L-1)磷酸二氢钾溶液中磷的吸附性能。结果表明,11种红色黏土对35和50 mg.L-1磷标准溶液的磷吸附量分别为0.52～0.86和0.52～1.18 mg.g-1,其中采自江苏的S9土样对2种浓度磷标准溶液的磷去除率均达90%以上;红色黏土中的铁、铝氧化物是除磷的主要控制因素,溶液中的磷主要与红色黏土中铁、铝氧化物相结合形成难溶性Fe-P和Al-P,土壤氧化铝含量与除磷效果呈显著正相关。可以通过向红色黏土及其他吸附剂中加入适量的铁、铝氧化物以提高对磷的吸附性能。

Physical and chemical properties of 11 different types of red clays collected from the sub-layer（20-40 cm） of wastelands in Yingtan of Jiangxi and Yixing of Jiangsu were analyzed and their performances of phosphorus adsorption in 2 solutions different in concentration（35 and 50 mg·L-1） were compared.Results show that the phosphorus adsorption capacites of the samples in the two solutions varied in the range of 0.52-0.86 and 0.52-1.18 mg·g-1,separately.Of the samples,S9 which was collected from Jiangsu demonstrated the highest P removal rate,being over 90% in both solutions.It was also found that iron and aluminum oxides in the red clays were the dominant controlling factors.They combined most of the phosphorus in the solutions,forming insoluble Fe-P and Al-P.The content of aluminum oxide was significantly and positively related to phosphorus removal rate.Therefore,it is advisable to add a proper amount of iron and aluminum oxides into red clay or some other adsorbents to improve their phosphorus adsorption capacity.