壳聚糖基絮凝剂絮凝高岭土的动力学及絮体结构  

Kinetics of flocculation of kaolinite by chitosan-based flocculants and the floc structure

作　　者：肖婷 邹文杰 余可馨 段旭琴 张志军[3] 徐瑞景 XIAO Ting;ZOU Wenjie;YU Kexin;DUAN Xuqin;ZHANG Zhijun;XU Ruijing(School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;National Institute of Clean and Low Carbon Energy,State Key Laboratory of Water Resource Protection and Utilization in Coal Mining,Beijing 102211,China;School of Chemical and Environmental Engineering,China University of Mining and Technology,Beijing 100083,China;Suzhou Sinoma Design and Research Institute of Non-metallic Minerals Industry Co.,Ltd,Suzhou 215004,China)

机构地区：[1]北京科技大学土木与资源工程学院,北京100083 [2]北京低碳清洁能源研究院,煤炭开采水资源保护与利用国家重点实验室,北京102211 [3]中国矿业大学(北京)化学与环境工程学院,北京100083 [4]苏州中材非金属矿工业设计研究院有限公司,苏州215004

出　　处：《工程科学学报》2025年第2期224-233,共10页Chinese Journal of Engineering

基　　金：煤炭开采水资源保护与利用国家重点实验室开放基金资助项目(GJNY-20-113-12);国家重点研发计划重点专项资助项目(2020YFC1807804);国家自然科学基金资助项目(51604019)。

摘　　要：开发多活性位点绿色高效絮凝剂对构建低絮凝剂用量的高效固液分离过程、实现选矿废水高效处理与循环回用具有重要意义.本文为考察天然阳离子型线性高分子壳聚糖接枝阳离子型聚丙烯酰胺(Chi-g-CPAM)的絮凝性能,改变引发剂质量分数将壳聚糖、丙烯酰胺和二甲基二烯丙基氯化铵通过紫外引发水溶液聚合法进行接枝共聚,合成了分子结构不同的Chi-g-CPAM,使用石英晶体微天平(QCM-D)研究了其在SiO2芯片表面的吸附行为和后继原位絮凝高岭土的动力学,分析了絮体结构变化;并采用动力学方程拟合以揭示絮凝机理;最后进行了絮凝剂沉降性能试验.结果表明,长支链可增强絮凝剂对高岭土的架桥网捕作用,加快沉降;接枝率越高则有助于降低上清液浊度.引发剂质量分数为0.10%所合成的Chi-g-CPAM支链相对多而长,在SiO2芯片表面平衡吸附量最大,为(–11.68±0.40)Hz,吸附的第Ⅰ、Ⅱ阶段K值分别为0.1814和0.5054,吸附构象趋于向外伸展,后继所絮凝高岭土量少且絮体结构疏松,架桥、网捕和电中和作用协同使其在沉降试验中表现的沉降速率最大(12.18 m·h–1),上清液浊度最低(13 NTU).支链多而长的Chi-g-CPAM絮凝高岭土的过程复杂,准一级、准二级动力学和Elovich方程对其拟合效果均较好.引发剂质量分数为0.15%和0.05%时,对应所合成支链多而短、支链少而短的Chi-gCPAM在SiO2表面呈扁平的“列车式”吸附构象,架桥和网捕能力低,絮凝沉降性能差.多活性官能团絮凝剂的分子结构影响其在矿物表面的吸附构象,是决定其絮凝性能的关键因素之一.本研究对选矿大分子药剂的分子结构设计具有重要意义.Solid–liquid separation is a critical component in treating mineral processing wastewater.Its effectiveness primarily hinges on the disruption of colloidal stability in the wastewater.Flocculants play a key role in destabilizing and dehydrating these colloids.Polyacrylamide is widely utilized as a flocculant in mineral processing plants.However,it requires large dosages and contains residual toxic monomers.Developing green,efficient flocculants with multiple active sites is vital for creating an efficient solid–liquid separation process with a low dosage of flocculants,enabling efficient treatment and recycling of mineral processing wastewater.In this work,acrylamide(AM)and dimethyl diallyl ammonium chloride(DMDAAC)are grafted onto the chitosan molecular chain through UV-initiated polymerization,obtaining chitosan-grafted-cationic polyacrylamide(Chi-g-CPAM)with varying molecular structures by modifying the mass fraction of initiator.The chemical structure and crystallinity of the grafted copolymer are characterized using Fourier transform infrared spectroscopy(FTIR),nuclear magnetic resonance spectroscopy(1H NMR),and X-ray diffraction.Chi-g-CPAM’s flocculation performance on kaolinite suspensions is evaluated through settling tests.The adsorption behavior of Chi-g-CPAM on silica surfaces and the flocculation kinetics of kaolinite are investigated using quartz crystal microbalance with dissipation.The adsorption morphology of Chi-g-CPAM on the SiO2 chip surface,floc structure,and flocculation mechanism are analyzed.The analysis reveals that long branched chains enhance Chi-g-CPAM’s bridging effect on kaolinite,accelerating settling.The abundant branched chains provide substantial positive sites,reducing supernatant turbidity,while short-branched chains result in a“train-like”adsorption conformation of flocculants on kaolinite surfaces,weakening the bridging effect.The grafting ratio of Chi-g-CPAM reaches 580.0%at an initiator mass fraction of 0.10%,with numerous long-branched chains.QCM-D measurements

关 键 词：壳聚糖 絮凝剂 石英晶体微天平 吸附构象 絮凝动力学 

分 类 号：TD926[矿业工程—选矿]