负载芽孢杆菌-粘土矿的夹心状多孔纳米纤维复合膜及其增强吸附重金属性能

It is hard to achieve the highly-efficient and safe removal for heavy metal pollution with the properties of low concentration and high toxicity from the water environment by single traditional adsorbent, and this kind of heavy metals is a serious threat to human health. Our previous research results indicated that the electrospun polystyrene (PS) fibrous mats exhibited highly porous structure, higher porosity and surface-area-to-volume ratio than traditional nanofibrous mats, which could be used for fabricating novel adsorbent. In this study, bacillus cereus (BCS), chitosan oligomers (COS) and organic rectorite (OREC) are selected as the raw materials. Firstly, prepare COS-OREC intercalated nanocomposites, and then mix them with PS to fabricate the PS/COS-OREC fibrous mats via electrospinning technique. Negatively charged BCS will be deposited on the surface of PS/COS-OREC mats via electrospraying technique. Repeat the electrospinning and electrospraying process alternately till the desired number obtained to get the reusable and sandwich-like composite active mats with the property of structural controllability. The adsorption enhancement ability of heavy metals and its relative mechanism by adding COS, BCS and OREC will be investigated. In addition, both the method and the effectiveness assessment of desorption and regeneration will be studied. Moreover, the microscopic mechanism of the interaction between the structure of the mats and the heavy metals will be analyzed. Furthermore, the structure-properties relationship between the surface properties of the composite mats and the heavy metals removal ability will be elucidated. The implementation of this project will help us to gain a new insight into improving the heavy metals adsorption ability of traditional adsorbent, and the developed approach for microbial immobilization and micro/nanostructures regulation utilized on pollutant control may also expand the application area of the novel materials in future.

水环境中"低浓度、高毒性"重金属污染物难以被高效安全去除，严重威胁人体健康，而传统的单一吸附材料较难达到理想的吸附效果。前期研究发现：静电纺聚苯乙烯纤维具有通体多孔结构，比普通纳米纤维有更高的孔隙率和比表面积，有望制备成新型吸附材料。本项目拟以芽孢杆菌、壳寡糖和有机累托石为组装对象，将壳寡糖插层有机累托石制备成纳米复合物，并与聚苯乙烯共混电纺制备多孔纤维复合膜，随后通过静电喷涂技术将带负电荷的蜡样芽孢杆菌沉积至该纤维膜表面。交替重复电纺-电喷步骤直至获得所需层数的结构可控夹心式复合纤维膜，并弄清壳寡糖、芽孢杆菌和有机累托石对复合膜重金属吸附性能的增强作用及其机理，研究其解吸再生方法和效果，分析膜结构与重金属相互作用的微观机理，阐明复合膜结构与其重金属吸附性能间的构效关系。本项目可为传统重金属吸附材料改性提供新思路，将微生物固定化和微/纳米结构调控用于污染物控制亦是对新材料领域的有益补充。

水环境中“低浓度、高毒性”重金属污染物难以被高效安全去除，严重威胁人体健康；电纺纳米纤维具有高的孔隙率和比表面积，有望制备成新型吸附材料。本项目主要围绕负载微生物的结构可控夹心式复合纤维膜的制备和实现其在重金属吸附上的应用开展研究。在实现不同组分电纺纳米纤维可控制备的基础上，采用层层自组装、定向冷冻、电喷雾、涂布机涂布等技术改性制备了具有大比表面积的复合纳米材料，对所得复合材料的结构进行了详细表征，通过工艺优化实现了对材料形貌、机械强度和亲疏水性等的控制。通过调节材料不同组分，改善了复合纳米材料物化特性和应用效果。利用壳聚糖、溶菌酶、累托石等抗菌组分在纳米纤维中的均匀负载实现了材料对大肠杆菌和金黄色葡萄球菌优良的抑制性能。通过静电喷涂技术将带负电荷的微生物沉积至电纺纤维膜表面，交替重复电纺-电喷步骤直至获得所需层数的结构可控夹心式复合纤维膜，纳米纤维作为支架有效提高微生物的附着，累托石和聚合物链的插层作用增大了材料的比表面积、强度和热学性能。吸附试验结果显示：复合材料对铅离子的吸附符合二级动力学方程，吸附最佳pH为6.5，最大吸附量达到了225±7mg/g，吸附解吸三次后，还能保持167.74mg/g的吸附量和78.26%的解吸率。本项目可为传统重金属吸附材料改性提供新思路，将微生物固定化和微/纳米结构调控用于污染物控制亦是对新材料领域的有益补充。