给水厂污泥对有机磷的吸附特性分析

通过批次试验对给水厂铝污泥吸附单磷酸腺苷的动力学、热力学和吸附等温模型进行研究，分析了初始磷浓度、温度和粒径对单磷酸腺苷（AMP）吸附的影响。试验结果表明:酸性和中性pH条件有利于铝污泥对AMP的吸附，粒径越小，吸附量越大，从实际应用的角度考虑，粒径1.0~2.0 mm的污泥最适合实际应用。准二级动力学模型能够很好地模拟铝污泥对单磷酸腺苷的吸附过程，表明吸附主要以化学吸附为主。Langmuir等温吸附模型能很好地描述铝污泥对单磷酸腺苷的吸附平衡。热力学分析表明，吸附过程为自发、吸热和熵增的过程。对红外光谱的分析表明，铝污泥吸附单磷酸腺苷的过程中有与Al相连的羟基的丢失以及Al—O—P键的增加，这一现象会随着初始磷浓度的增加而加剧，表明铝污泥主要是通过配体交换吸附单磷酸腺苷。

ADSORPTION PROPERTIES OF ORGANIC PHOSPHORUS IN WATER BY WATER TREATMENT RESIDUAL

The adsorption kinetics, thermodynamics experiments and adsorption isothermal models of adsorption of adenosine monophosphate(AMP) on aluminum-based water treatment residual (Al-WTR) were studied by batch test. The effects of initial phosphorus concentration, temperature and particle size on the adsorption of AMP were analyzed. The experimental results showed that AMP uptake was favored under neutral and acidic conditions. The smaller the particle size, the larger the adsorption amount. The Al-WTR with size of 1.0~2.0 mm was most suitable for practical application. The pseudo-second-order kinetic model well fitted the adsorption process of Al-AMP on WTR, which indicated that the adsorption was mainly based on chemical adsorption. The Langmuir isotherm model described the adsorption equilibrium well, and the thermodynamic analysis manifested that the adsorption process was a spontaneous, endothermic and entropy-increasing process. The analysis of Fourier-transform infrared spectrum analysis (FTIR) showed that there was a loss of hydroxy groups associated with Al and an increase in Al-O-P bonds during the adsorption of AMP on Al-WTR. This phenomenon was enhanced by the increase of initial phosphorus concentration, indicating that the adsorption of Al-WTR on AMP mainly fulfilled through ligand exchange.