高岭土对畜禽废水中磷的净化效果及其费效分析

Phosphate Removal Efficiency of Kaolin in Livestock and Poultry Wastewater and Its Cost-Benefit Analysis

以高岭土为材料制备不同改性产品,用来吸附净化畜禽废水中的磷,并通过静态吸附和动态柱吸附试验分析其吸附净化磷的费用和效益。结果发现,不同改性处理均能提高高岭土对磷的吸附性能,但不同改性方法的效果仍存在一定的差异。针对盐酸改性,随着酸用量的增加,改性后高岭土对磷的吸附能力呈逐渐增加趋势。针对加热处理,当煅烧温度低于500 ℃时,高岭土对磷的吸附容量随着温度的升高逐渐增加,可提高3倍左右;而煅烧温度为500~ 600 ℃时,吸附量随着温度的升高基本保持不变,之后反而呈下降趋势。层状双氢氧化物改性高岭土对磷的吸附量也显著高于天然高岭土,且高于500 ℃热改性高岭土。但综合考虑改性成本、残留磷溶液浓度、吸附量、去除率等条件,在处理ρ(磷)为20 mg·L^-1的畜禽废水时,500 ℃热改性高岭土对磷吸附净化的效益比最高,约为1 421 mg·元^-1。

The ability and purification efficiency of different modified kaolins for phosphate adsorption in livestock and poultry wastewater were detected. Batch adsorption experiment and dynamic column adsorption experiment were used to evaluate the cost-benefit of kaolin used in the purification of phosphate-containing livestock and poultry wastewater. The results show that different modification treatments could significantly improve the adsorption performance of kaolin on phosphate,but there are some differences between the different modification methods. For hydrochloric acid modification,with the increase of acid dosage,the adsorption capacity of modified kaolin to phosphate has gradually increased. When the heating temperature was lower than 500 ℃,the adsorption performance of kaolin increased gradually with the temperature,and could be increased by about 3 times. When the calcination temperature was 500 ~ 600 ℃,the adsorption capacity kept no change with the increase of temperature,then when the temperature was higher than 600 ℃,it showed a downward trend. The saturation adsorption of phosphate on layered double hydroxide-modified kaolin is significantly higher than that of 500 ℃ thermally modified kaolin. However,on comprehensive consideration of modification cost,residual solution concentration,adsorption capacity,removal rate and other purification effects,in the treatment of 20 mg·L^-1 phosphate-containing livestock and poultry wastewater or so,adsorption performance of 500 ℃ thermally modified kaolin is the best,and the cost is lowest and the cost-benefit ratio is the highest,which is about 1421 mg P·yuan^-1.