新型凹凸棒石复合材料制备及其吸附性能

Preparation and adsorption properties of new attapulgite composites

有效去除污水中含氮含磷物质并合规排放成为水处理技术领域有待解决的关键课题。以凹凸棒石、沸石、硅藻土及氧化镧为原料制备球状固体复合材料,并对复合材料表面结构及元素含量进行表征,重点研究了复合材料在含氮含磷模拟废水中达到最佳吸附效果的工艺条件。结果表明:新型复合材料的氧化镧最优添加量为1%,选取600℃的煅烧温度。随材料投加量的减少及pH的不断增大,镧改性后的复合材料对氮、磷的去除率整体呈下降趋势。随初始质量浓度由2.0 mg/L增加至10.0 mg/L,氮、磷的去除率变化均呈先增后降趋势,而随环境温度的升高,氮、磷去除率均先降低后升高,复合材料吸附氮磷污染物的最优工艺条件为环境温度25℃,pH取4.0,氮、磷溶液初始质量浓度取5 mg/L,投入复合材料与溶液质量比1∶20。此外,吸附动力学拟合结果表明,复合材料对氮、磷的吸附动力学特性与一级动力学模型吻合。

At present,wastewater from industrial production is directly discharged into lakes and rivers,which could cause the nitrogen and phosphorus content of water to exceed the environmental protection standard value.The effective removal of nitrogen and phosphorus substances in sewage compliance discharge is a crucial issue to be solved in the field of water treatment technology.Adsorption method is widely used in the field of modern wastewater treatment technology because of its convenience,good treatment effect and wide application range.This study uses attapulgite,zeolite,diatomite,and lanthanum oxide as raw materials to prepare spherical solid composite materials.Through static adsorption experiments,the technological conditions required for the optimal adsorption effect of the composite mate-rials in nitrogen and phosphorus containing wastewater are studied,and through the SEM imaging and EDS analysis,the surface structure and element content of the composite were characterized and analyzed to explore the adsorption mechanism.The results show that the optimum preparation conditions of spherical composites are calcined at 600℃ with 1%lanthanum oxide content.The results of single factor static adsorption experiment show that all factors have different degrees of influence on the adsorption amounts of nitrogen and phosphorus.With the decrease of material dosage and the increase of pH,the removal rate of nitrogen and phosphorus of lanthanum modified composites show a downward trend.As the initial mass concentration increases from 2 mg/L to 10 mg/L,the removal rates of nitrogen and phosphorus increase firstly and then decrease,with the increase of ambient temperature,the removal rates of nitrogen and phosphorus decrease firstly and then increase.When the initial mass concentration of nitrogen and phosphorus in solution is 5 mg/L,the optimal process conditions for the adsorption of nitrogen and phosphorus pollutants by composite materials are the temperature of 25℃ and pH of 4 in the nitrogen and phosphorus solution.When the ratio of composite material to solution was 1∶20,the removal rates of nitrogen and phosphorus by filter material reached 63.6% and 92.6%,respectively.In addition,the adsorption kinetics fitting results show that the adsorption kinetics characteristics of nitrogen and phosphorus are in good agreement with the first-order kinetic model.