淡紫拟青霉菌/双网络复合凝胶体系的构建及其镉吸附分子调控机制研究

Cadmium pollution has become a serious environmental issue，which is a serious threat to human health and survival. For this purpose, we propose a novel idea to treat wastewater with low concentration cadmium ions by employing double network hydrogel of PDMA-GG-P.lilacinus M1, which is based on a high Cadmium-resistant fungus P.lilacinus M1 by using autofilter. This project is focused on researching the Quantitative Structure-activity Relationship (QSAR) between the structure of this composite gels and the adsorption performance for Cadmium by modern analytical techniques and mechanical performance tests. The influence of fungal embedding on the structure, mechanical strength and the permeability of the composite gel will be systematically investigated, contrarily, the effect of the structure, mechanical strength and the permeability of the composite gel on the growth and metabolism of bacterial also will be deeply studied. This project is anticipated to realize the controllable construction and in situ synthesis of composite gel. Besides,the synthetic molecular mechanism of intracellular polysaccharides and the interaction between the groups of gel and the extracellular secretion of fungal polysaccharides will be systematically investigated by researching on high-throughput sequencing of fungal regulatory network construction and related function. This project is anticipated to explain the mechanism of heavy metal Cd (Ⅱ) absorption by composite gel system, and the aim is at the preparation of better gel to improve its adsorption capacity of heavy metal cadmium. This project provides an important scientific basis for the design, preparation and adsorption of heavy metal cadmium, and lay a theoretical foundation.

针对严重影响人类健康与生存的重金属镉污染这一重大环境问题，本项目以自主筛选的抗镉淡紫拟青霉菌为研究基础，提出构建N、N二甲基丙烯酰胺、结冷胶、淡紫拟青霉菌的双网络新型复合凝胶体系处理低浓度含镉污水的新思路。项目利用现代分析测试手段拟对复合凝胶的结构与镉吸附性能的构效关系展开深入的研究，着重考察真菌包埋对凝胶结构、机械强度及通透性的影响；反之探讨凝胶结构、机械强度等力学性能对真菌的活性、生长及代谢规律的影响，实现复合凝胶网络的可控合成与真菌的高效包埋。同时拟通过基于高通量测序的真菌调控网络构建以及功能研究，重点剖析真菌胞内多糖的合成分子机制及凝胶基团与真菌多糖胞外分泌之间的相互作用关系，尝试阐释复合凝胶体系吸附重金属镉分子调控机制，旨在反馈凝胶的制备，提高它的重金属镉的吸附能力。为环境友好的功能性复合凝胶的设计、制备及吸附重金属镉分子机制提供重要科学依据、并奠定理论基础。

水凝胶是一种具有高含水量的三维网络的聚合物材料，具有较快的扩散速率、高吸附量、操作简单、方便回收利用等优点，在重金属吸附领域具有巨大应用潜力。本项目采用淡紫拟青霉菌种和 N-异丙基丙烯酰胺合成了微凝胶并将其作为交联剂合成了琼脂/聚（丙烯酰胺-co-丙烯酸羟乙酯）双网络凝胶， 并使用三乙烯四胺进行胺基化改性。 随后对该凝胶进行了理化性能表征。 力学测试证明该凝胶具有优异的力学性能。 溶胀测试中表明该过程符合非 Fikian 定律，扩散速率等于高分子链的松弛速率。 吸附实验证明吸附剂在 pH 4-7 时具有较好的吸附性能，干扰离子低浓度下对吸附影响不大。 通过单组份和混合组分的选择性吸附实验中，对 Pb(II)的选择性最好，而且随着混合组分的浓度降低，分配系数变大。在等温吸附实验中，随着温度的升高，吸附量降低。 在 20℃时， 通过 Langmuir 模型计算出 Cd(II)和 Pb(II)的最大理论吸附量分别为 118.36 和 182.23 mg/g。通过 XPS 吸附机理的研究发现，该吸附过程主要依靠修饰改性上胺基和丙烯酰胺的酰胺基。最后，将该水凝胶吸附剂应用于重金属废水的吸附， 取得了良好的治理效果。