改性淀粉混凝剂的疏水性对水中不同污染物混凝性能的影响与机理研究  

Influence of the hydrophobicity of the starch-based coagulant on the coagulation of various pollutants in water and the study of its mechanism

作　　者：胡新宇 陈继锡 杨琥[1,2] HU XinYu;CHEN JiXi;YANG Hu(State Key Laboratory of Pollution Control and Resource Reuse,School of Environment,Nanjing University,Nanjing 210023,China;Quanzhou Institute for Environmental Protection Industry,Nanjing University,Quanzhou 362000,China)

机构地区：[1]南京大学环境学院,污染控制与资源化研究国家重点实验室,南京210023 [2]泉州南京大学环保产业技术研究院,泉州362000

出　　处：《中国科学：技术科学》2023年第1期112-126,共15页Scientia Sinica(Technologica)

基　　金：国家自然科学基金(批准号:42061144014);泉州市科技计划(编号:2021CT001)资助项目。

摘　　要：我国部分江、河、湖泊等地表水呈有机微污染特征,这已成为制约水环境质量进一步提升的关键因素.混凝工艺因其具有成本低廉及操作简便等特点,是处理地表水的常见工艺之一.针对传统无机混凝剂及有机合成高分子混凝剂去除地表水中有机微污染物效率不高,且使用过程中存在二次污染风险等问题,同时考虑到有机微污染物分子结构上不仅含有亲水基团还含有大量疏水基团,本文以一种兼具绿色环保、来源广泛且成本低廉等特点的天然高分子——淀粉为原材,以丙烯酰胺及含有不同长度碳链的季铵盐单体为改性剂,通过接枝共聚技术,制得四种具有相同电荷密度不同疏水程度且水溶性良好的系列改性淀粉混凝剂(CS-DMRCs).选取高岭土(Kaolin)、腐殖酸钠(NaHA)和牛血清蛋白(BSA)分别模拟地表水中常见无机胶体颗粒和有机微污染物,系统探究了不同疏水程度的改性淀粉混凝剂对Kaolin,NaHA和BSA在单一及其二元和三元混合污染物模拟水样的混凝性能.进一步通过同步检测混凝后模拟水样上清液zeta电位、产生絮体的絮体尺寸和分形维数、絮体表面形貌以及絮体实时生长过程中尺寸变化情况等,详细探讨了CS-DMRCs疏水性对其混凝性能影响及混凝机理.发现本文制得的四种CS-DMRCs中,疏水性最强的改性淀粉混凝剂具有最佳的混凝性能,这是由于其不仅具有良好的电中和及黏结架桥作用,其侧链疏水基团可通过疏水缔合作用增强改性淀粉混凝剂与有机微污染物间的相互作用,形成大而密实的絮体,进而有效提高混凝性能.还采用CS-DMRCs尝试处理一种实际地表水:南京九乡河河水,进一步证实了该改性淀粉混凝剂净化有机微污染地表水的有效性.综上,CS-DMRCs制备方法高效简便,对地表水中无机及有机污染物均具有良好的去除效果,在实际应用中应具有广阔的前景.Parts of surface water in China,including some rivers and lakes,show the characteristics of micropollution containing excessive dissolved organic matter,which has become a key factor in restricting the improvement of water quality.Coagulation is one of the most popular technologies in the purification of surface water owing to its low cost and simple operation.However,traditional coagulants,including inorganic and organic synthetic polymer coagulants,usually show a low efficiency in removing organic micropollutants from surface water and pose the risk of secondary pollution.Furthermore,the molecular structures of organic micropollutants contain hydrophilic and a large number of hydrophobic groups.Considering these facts,in this study,starch(St),a natural polymer with the characteristics of environmental friendliness,wide source,and low cost,was used as the raw material and acrylamide and various quaternary ammonium salts containing different lengths of carbon chains were used as modifiers.Accordingly,four modified starch coagulants(CS-DMRCs) with the same charge density and good water solubility but different degrees of hydrophobicity were designed and fabricated using graft copolymerization.Kaolin particles,sodium humate(Na HA),and bovine serum albumin(BSA) were used as the simulated sources of inorganic colloids and different organic pollutants in the micropolluted turbid surface water.The effects of the hydrophobicity of four St-based coagulants on the removal of kaolin particles,Na HA,and BSA from their single,binary,and ternary pollutant aqueous systems were investigated systematically.Based on the apparent coagulation performance,the floc properties,including floc size,compactness,surface morphology,breakage and recovery behaviors,and the zeta potentials of the supernatants after coagulation,the coagulation mechanisms associated with the structural features of the St-based coagulants and treated pollutants were explored and discussed in detail.The St-based coagulants with a higher hydrophobicity showed bett

关 键 词：接枝改性淀粉混凝剂 疏水性 有机微污染物 浊度 混凝性能 混凝机制 

分 类 号：X52[环境科学与工程—环境工程]