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.