【作者】 李伟；

【导师】 梁越敢； 张浏；

【作者基本信息】 安徽农业大学 ， 农业硕士（专业学位）， 2020， 硕士

【摘要】 过量氮、磷元素的排放会造成水体富营养化,吸附去除氮磷既是消减氮磷污染的有效措施,又是氮磷回收资源化的可行方法。本文利用金属氧化物改性凹凸棒土作为吸附剂,探究改性凹凸棒土对磷、氨氮的吸附特性,并阐明其吸附机理。锆改性凹凸棒土吸附除磷的特性研究表明,与原凹凸棒土相比,锆改性凹凸棒土对磷的吸附效率提高76.85%;p H变化对锆改性吸附剂吸附除磷影响较小;共存离子HCO₃^-、CH₃COO^-、Ca²⁺和Mg²⁺会降低吸附除磷效率,而Fe³⁺离子影响较小。改性吸附剂理论最大吸附量为17.04 mg/g,准二级动力学较好地描述改性吸附剂的除磷过程,暗示化学反应为速率控制步骤。红外光谱与XRD表征、磷浸提形态分析和平均吸附能分析表明,锆改性凹凸棒土吸附除磷的主要机理是静电作用和配位交换。氢氧化钙改性凹凸棒土吸附除磷的特性研究表明,与原凹凸棒土相比,钙改性凹凸棒土对磷的吸附效率提高68.17%;p H变化对钙改性吸附剂吸附除磷影响较小;共存离子HCO₃^-、NH₄⁺、CH₃COO^-和Fe³⁺离子会降低吸附除磷效率,同时发现Ca²⁺离子会提升钙改性吸附剂除磷效率,Mg²⁺阳离子的影响较小。改性吸附剂理论最大吸附量为23.87 mg/g,钙改性凹凸棒土的除磷过程为速率控制步骤。磷浸提形态分析和平均吸附能分析表明,钙改性吸附剂除磷的主要机理是静电作用和表面沉淀。锆改性凹凸棒土吸附除氮磷的特性研究表明,与原凹凸棒土相比,锆改性凹凸棒土对磷的吸附效率提高76.39%,氨氮吸附效率提高86.27%;中性条件下吸附剂对氮磷的吸附效果最佳;共存离子HCO₃^-和NO₃^-阴离子会降低吸附剂的氨氮去除效率,同时发现K⁺和Na⁺阳离子会显著降低吸附剂氨氮去除效率,而Mg²⁺阳离子影响较小。改性吸附剂的氨氮最大理论吸附量为52.08 mg/g,磷最大理论吸附量为24.63 mg/g。锆改性凹凸棒土的吸附氮磷过程为速率控制步骤。平均吸附能分析表明,锆改性凹凸棒土吸附除氮磷的主要机制为化学吸附。锆和氢氧化钙改性增加凹凸棒土的氮磷吸附性能,且吸附机理主要为静电作用和配位交换,具有一定理论价值。因此,改性凹凸棒土有望成为新型高效吸附材料。更多还原

【Abstract】 Excessive emission of nitrogen and phosphorus will cause eutrophication of the water body.Adsorption and removal of nitrogen and phosphorus were not only effective measures to reduce nitrogen and phosphorus pollution,but also a feasible method for recycling nitrogen and phosphorus.In this paper,metal oxide modified attapulgite was used as an adsorbent to explore the adsorption characteristics of modified attapulgite for phosphorus and ammonia nitrogen,and to clarify its adsorption mechanism.The study of the characteristics of phosphorus absorption by zirconium modified attapulgite showed that compared with the original attapulgite,the adsorption efficiency of zirconium-modified attapulgite for phosphorus increased by 76.85%;the change of p H has little effect on the removal of phosphorus by the zirconium-modified adsorbent;coexisting ions HCO₃^-,CH₃COO^-,Ca²⁺and Mg²⁺will reduce the efficiency of phosphorus removal,while Fe³⁺ion had little effect.The theoretical maximum adsorption capacity of modified adsorbent was 17.04 mg/g.Quasi-second order kinetics better described the phosphorus removal process of the modified adsorbent,that was,the chemical reaction was the rate control step.FT-IR and XRD characterization,phosphorus leaching morphological analysis and average adsorption energy analysis showed that the main mechanism of phosphorus removal by zirconium-modified attapulgite was electrostatic interaction and coordination exchange.The study of the characteristics of phosphorus absorption by calcium hydroxide modified attapulgite showed that compared with the original attapulgite,the adsorption efficiency of calcium-modified attapulgite for phosphorus increased by 68.17%;the change of p H has little effect on the removal of phosphorus by the calcium-modified adsorbent;coexisting ions HCO₃^-,NH₄⁺,CH₃COO^-and Fe³⁺will reduce the efficiency of phosphorus removal,and Ca²⁺will promote the phosphorus removal efficiency of calcium modified adsorbent,Mg²⁺cation less affected.The theoretical maximum adsorption capacity of modified adsorbent was 23.87 mg/g.Quasi-second order kinetics better described the phosphorus removal process of the modified adsorbent,that was,the chemical reaction was the rate control step.Phosphorus leaching morphological analysis and average adsorption energy analysis showed that the main mechanism of phosphorus removal by calcium-modified attapulgite was electrostatic action and surface precipitation.The study of the characteristics of phosphorus and ammonia nitrogen absorption by zirconium modified attapulgite showed that compared with the original attapulgite,the adsorption efficiency of zirconium-modified attapulgite for phosphorus increased by76.39%;the adsorption efficiency of zirconium-modified attapulgite for ammonia nitrogen increased by 86.27%;the adsorbent had the best adsorption of nitrogen and phosphorus under neutral conditions;coexisting ions HCO₃^-and NO₃^-anions reduced the ammonia nitrogen removal efficiency of the adsorbent,and it was found that K⁺and Na⁺cation will significantly reduce the ammonia nitrogen removal efficiency of the adsorbent,while Mg²⁺cation had less effect.The theoretical maximum phosphorus adsorption capacity of modified adsorbent was 23.87 mg/g and the maximum ammonia nitrogen adsorption capacity was 52.08 mg/g.The quasi-second-order kinetics better described the nitrogen and phosphorus adsorption process of zirconium-modified attapulgite,that was,the chemical reaction was the rate control step.The average adsorption energy analysis showed that the main mechanism for the removal of nitrogen and phosphorus by zirconium-modified attapulgite was chemical adsorption.The modification of zirconium and calcium hydroxide significantly improved the adsorption performance of attapulgite,and the adsorption mechanism was mainly electrostatic interaction and coordination exchange,which had certain theoretical value.Therefore,the two modified attapulgite clays in this study were expected to become a new type of high-efficiency adsorption materials.更多还原