含高密度胺基新型凹土基吸附材料的制备及其吸附性能研究

Heavy metal pollution has become one of the most serious environmental problems today. The treatment of heavy metals is of special concern due to their recalcitrance and persistence in the environment. Adsorption is now recognized as an effective and economic method for heavy metal wastewater treatment. The adsorption process offers flexibility in design and operation and in many cases will produce high-quality treated effluent. In addition, selective adsorption of special heavy metals in wastewater will recovers and reuses the metals. Quite evidently, high performane functional adsorbent would be play a key role in the technology. .In this project, a novel functional adsorption material and preparation method is proposed. The material contains high density of amine group and is prepared by grafting polyamidoamine dendrimers on attapulgite nanofiber. Main attentions are paid to the effects of preparation conditions on the structure of the new adsorbent. The relationship between the adsorbent structure and its surface properties and adsorptive properties are also investigated based on instrumental analysis and theoretical calculation using Materials Studio program. The adsorption and desorption mechanisms of the adsorbent are studied. The treatment process of wastewater containing heavy metals based on new material adsorption is investigated. .The research will provide a new material for treatment of the heavy metal wastewater and reuse of heavy metals. The results will also provide a theoretical and technical basis for design, preparation and application of functional adsorption materials made from low-cost natural clay.

引入特定功能组分构建选择性吸附体系，来实现重金属离子选择性吸附分离，既防止环境污染，还能实现资源化回收，显然，高性能吸附材料是关键。项目基于凹土独特的纳米棒晶结构，通过接枝聚酰胺-胺(PAMAM)树状分子作为功能基团，设计制备对重金属离子高效吸附的新型吸附材料-表面含高密度胺基的PAMAM/凹土吸附材料。重点研究新型吸附材料的制备方法；考察制备条件对材料结构的影响，结合仪器表征和Materials Studio 4.1软件的理论计算，探讨材料结构与其表面性质和吸附性能之间的关联性，揭示其对重金属离子的吸附和脱附机理；对基于新材料的重金属废水吸附处理过程进行研究。项目创新性地提出含高密度胺基凹土吸附材料的概念和制备新思路，制备具有树状结构的高胺基密度凹土吸附材料，提高材料对重金属离子的吸附效率和胺基利用率。研究成果将为基于低成本天然粘土的功能化吸附新材料的设计、制备和应用提供理论和技术基础。

引入特定功能组分构建选择性吸附体系实现重金属离子选择性吸附分离，既防止环境污染，还能实现资源化回收，显然，高性能吸附材料是关键。项目基于凹土独特的纳米棒晶结构，通过接枝聚酰胺-胺(PAMAM)树状分子作为功能基团，设计制备对重金属离子高效吸附的新型吸附材料-表面含高密度胺基的PAMAM/凹土吸附材料。通过氨基硅烷改性凹土，利用氨基功能化凹土基吸附材料表面的活性位点，实现PAMAM在凹土表面的固定化，制备出0.5~4.0代PAMAM-ATP复合吸附材料，系统研究研究了1.0~4.0代PAMAM-ATP复合吸附材料的吸附性能。氨基功能化凹土基吸附材料与丙烯酸甲酯进行迈克尔加成反应合成ATP-G0.5复合材料，确定4.0g氨基功能化凹土基吸附材料与88.8mmol丙烯酸甲酯在50°C反应24h，复合材料的吸附性能最好。通过ATP-G0.5与乙二胺进行酰胺化反应合成ATP-G1.0复合吸附材料的制备条件考察，得到2.1g按上述条件制备的ATP-G0.5复合材料与179.3mmol乙二胺在50°C反应48h，复合材料的吸附性能最好。XPS分析表明，随着整代产品代数的增加，其相应的端胺基也逐步增加，因而氮含量也增加。以胺基为端基的ATP-G0、ATP-G1、ATP-G2、ATP-G3、ATP-G4整代产品对Pb2+和活性红3BS的吸附性能呈逐渐递增的趋势，且显示了其优良的吸附性能，随着代数的增加，其对Pb2+和活性红3BS的吸附性能大大提高。吸附剂对Pb2+和活性红3BS吸附过程符合拟二级动力学方程，吸附等温线符合Langmuir方程。20°C时的ATP-G0、ATP-G1、ATP-G2、ATP-G3、ATP-G4五种吸附剂对Pb2+的饱和吸附量分别为68.5、151.1、196.5、389.1和694.4 mg/g，20°C时的ATP-G1、ATP-G2、ATP-G3、ATP-G4四种吸附剂对活性红3BS的饱和吸附量分别为69.930mg/g、121.951mg/g、242.718mg/g、322.581mg/g。。对Pb2+/Hg2+、Pb2+/Cd2+、Pb2+/Hg2+/Cd2+混合金属离子溶液中， ATP-G4对Pb2+具有很好的选择性吸附性能，其竞争吸附能力依次为Pb2+＞Hg2+＞Cd2+。研究结果为重金属离子选择性分离回收和印染废水处理提供材料和技术支撑。