改性沸石同步深度脱氮除磷的实验研究

Experimental study on simultaneous removal of ammonium and phosphate in treated wastewater by modified zeolite

以氯化铝、硫酸镁为活性剂,采取高温活化,对天然沸石进行改性,并通过正交试验优化了改性工艺。以模拟二级出水为研究对象,考察了改性沸石同步去除水样中氮磷的效果及其影响因素,并对不同温度下改性沸石对磷酸盐和氨氮的吸附平衡和吸附热力学,以及脱氮除磷机理进行了探讨。结果表明,15 min后改性沸石脱氮除磷过程基本完成,其pH值范围与实际污水相符,最佳pH值为8;当投加质量浓度为0.8 g/L时,出水中氨氮浓度和总磷浓度均达到景观环境用水水质标准(GB/T18921-2002)。改性沸石对氨氮和磷酸盐的吸附均符合Langmuir等温吸附方程。热力学参数ΔG0、ΔH0分别为正值和负值,表明该吸附是一个自发的吸热过程。

Modification treatment of natural zeolite was conducted by means of addition of AICl3 and MgSO4 as activator at high temperature. The orthogonal experiments were adopted to optimize the modification technology. The simulative secondary effluent was employed, and efficiencies and their influencing factors of simultaneous removal of ammonium and phosphorus were investigated. Meanwhile the sorption equilibrium at a series of temperatures and the mechanism of modified zeolite was discussed. The results showed that process for removal of ammonium and phosphorus could be basicly finished in 15 min ; range of pH value was in accord with that of the practical secondary effluent,and the opimal pH value was 8. When the amount of modified zeolite added was above 0. 8 g/L, the mass of concentration of phosphorus and ammonium after the treatment was accord with the water quality standard for scenic environment use （GB/T 18921-2002）. The adsorption of ammonium and phosphate with modified zeolite follows the the Langmuir isotherm model. And △G^o and △H^o were respectively nega- tive and positive, so the adsorption process was a spontaneous and endothermic reaction.