羟基铝蛭石污泥对雨水中磷的吸附特性与机制

Adsorption Characteristics and Mechanism of Hydroxy Aluminum Vermiculite Sludge on Phosphorus in Rainwater

为强化生物滞留池对雨水中磷素的去除效果,该文以膨胀蛭石和铝污泥为研究对象,改性处理制备出羟基铝蛭石(HAV),通过将羟基铝蛭石和铝污泥按比例混合成固体颗粒,以500℃焙烧后冷却,制得羟基铝蛭石污泥颗粒(HAVSP)。实验探究了HAVSP在不同pH、投加量和初始磷浓度条件下对磷吸附能力的影响,结果表明在pH=6,投加量为5 g/L,初始浓度为4 mg/L时,HAVSP能达到较好的吸附效果,最大吸附量可达2.11 mg/g。通过物相分析结果表明,与未经过改性蛭石相比,HAV的表面更粗糙,丰富了表面官能团组成,并增加了微孔数目、金属离子及氧化物含量。吸附等温线能较好地符合Langmuir和Frendich方程,由Langmuir方程计算出HAVSP的最大饱和吸附量为1.522 mg/g;由Lagergren准一级动力学方程模型得出HAVSP对磷的平衡吸附量与实验所得平衡吸附量偏差最小。

To enhance the removal effect of phosphorus in rain water by biological retention tank, the hydroxy aluminum vermiculite(HAV) was prepared by modified treatment with expanded vermiculite and aluminum sludge. Hydroxy aluminum vermiculite sludge particles(HAVSP) were prepared by mixing hydroxy aluminum vermiculite and aluminum sludge into solid particles in proportion and cooling after 500 ℃ roasting. The effect of HAVSP on phosphorus adsorption capacity under different pH, dosage and initial phosphorus concentration was investigated. The results showed that under the pH 6, the dosage 5 g/L,and the initial concentration 4 mg/L, HAVSP could achieve better adsorption effect, with the maximum adsorption capacity up to 2.11 mg/g. Compared with unmodified vermiculite, the surface of HAV is rougher, which enriches the composition of surface functional groups and increases the number of micro-pores and the content of metal ions. The adsorption isotherms can better conform to the Langmuir and Frendich equations. The maximum saturated adsorption capacity of the HAVSP is calculated from the Langmuir equation to be 1.522 mg/g;and the deviation between the equilibrium adsorption capacity of phosphorus and the equilibrium adsorption capacity obtained from the Lagergren quasi-first-order kinetic equation model is the smallest.