铝锰复合氧化物负载沸石对氨氮和磷的同步吸附特性

采用氧化还原-共沉淀法将铝锰复合氧化物负载到沸石表面制成颗粒型吸附材料，探究了该吸附剂同步去除氨氮（NH4+-N）和磷（P）的吸附动力学和吸附等温线特征，并讨论了吸附剂投加量和溶液pH值对吸附效果的影响。结果表明：铝锰复合氧化物改性沸石（aluminum-manganese bimetal oxide coated zeolite，AMOCZ）对NH4+-N及P的吸附动力学曲线均符合拟二阶吸附动力学方程的特征；NH4+-N的吸附等温线数据可用Freundlich方程进行较好地拟合，而Langmuir方程更适用于描述P的吸附等温线特征。NH4+-N和P共存时，两者在AMOCZ表面的饱和吸附量分别从单独体系下的1.24和6.43 mg·g-1变为8.17和6.51 mg·g-1。这说明P的存在可显著促进AMOCZ对NH4+-N的吸附，而NH4+-N的存在对P的吸附无显著影响。此外，复合污染条件下，P的存在在pH=3~10范围内均能促进AMOCZ对NH4+-N的吸附；NH4+-N在pH为3~8时对P的吸附起促进作用，pH大于8时则会抑制AMOCZ对P的吸附。

Characteristics of simultaneous adsorption of phosphate and ammonia nitrogen onto aluminum-manganese bimetal oxide coated zeolite

This study focused on the characteristics and mechanisms of the simultaneous adsorption of ammonia nitrogen and phosphate using aluminum-manganese bimetal oxide-coated zeolite (AMOCZ). The kinetics data of ammonia nitrogen and phosphate adsorption are well described by a pseudo-second-order model. The Freundlich model fits the isotherm data of ammonia nitrogen satisfactorily, while the Langmuir model fits the phosphate data well. The maximum adsorption amounts of ammonia nitrogen and phosphate are 1.24 and 6.43 mg·g-1, respectively, at T=298 K (pH 7.0) in single-pollutant systems; these values change to 8.17 and 6.51 mg·g-1, respectively, under combined pollutant conditions. Moreover, the presence of phosphate can promote the adsorption of ammonia nitrogen from pH 3 to pH 10. Similarly, the presence of ammonia nitrogen can introduce a positive effect on phosphate adsorption in the pH range of 3.0—8.0. In contrast, a negative effect of ammonia nitrogen was observed for phosphate removal in the pH range of 8.0—10.0.