接枝型阳离子淀粉絮凝剂对石材废水的絮凝降浊性能与机理研究  

Flocculation performance and mechanisms of a graft cationic starch-based flocculant in turbidity removal for a stone wastewater

作　　者：王禹洋 陈继锡 杨娇娇 王永峰[2] 胡大波[2] 刘波[1,2] 龙超[1,2] 杨琥[1,2] Yuyang Wang;Jixi Chen;Jiaojiao Yang;Yongfeng Wang;Dabo Hu;Bo Liu;Chao Long;Hu Yang(State Key Laboratory of Pollution Control and Resource Reuse,School of the 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：化学》2023年第5期883-894,共12页SCIENTIA SINICA Chimica

基　　金：泉州市科技计划(编号:2021CT001)资助项目。

摘　　要：混凝/絮凝工艺是去除废水中悬浮胶体颗粒、降低浊度的有效手段.本研究以一种常见的天然高分子材料——淀粉为原材,以丙烯酰胺和甲基丙烯酰氧乙基三甲基氯化铵为共聚单体,采用接枝共聚技术,开发了一系列接枝链分布相同、但电荷密度及平均接枝链链长不同的接枝型阳离子淀粉改性絮凝剂:淀粉接枝共聚丙烯酰胺-聚甲基丙烯酰氧乙基三甲基氯化铵(St-G).并以一种具有高浊度特征的行业废水——石材废水为研究对象,详细讨论了St-G的结构因素(电荷密度与平均接枝链链长)及环境因素(絮凝剂投加量和pH等)对其絮凝性能的影响,结合絮凝后上清液Zeta电位、絮体结构的动态监测结果以及扩展DLVO(Derjguin-Landau-Verwey-Overbeek)胶体稳定理论等,详细探究了其絮凝机理.研究结果表明,St-G对石材废水的絮凝性能明显优于传统无机混凝剂聚合氯化铝,St-G对石材废水的除浊作用主要是电荷碎片机制为主导,且与黏结架桥作用协同作用的结果.随着St-G电荷密度的增加,其浊度去除率增加而对应最佳絮凝剂用量减少,且絮体破碎后恢复因子增加;而絮体尺寸、絮体生长速度及其破碎因子均与St-G平均接枝链链长呈正相关.扩展DLVO理论结果也表明,St-G与石材废水胶体颗粒间总相互作用能为负值,且与电荷密度呈负相关,其中电荷密度最大的St-G1总相互作用能最低,最易发生电中和混凝作用,具有最佳的降浊效果.综上可知,St-G的制法安全简便、降浊效果显著、绿色环保且价格低廉,在石材加工等行业废水处理中有着良好的应用前景.Coagulation/flocculation is an effective technique to remove suspended colloidal particles and reduce turbidity in various wastewater samples.In this study,a series of graft cationic starch-based flocculants,St-g-poly(acrylamide-co-methacryloyloxyethyl trimethyl ammonium chloride)(St-G),were designed and fabricated using starch as a raw material and acrylamide and(2-methacryloyloxy-ethyl)trimethyl ammonium chloride as graft co-monomers.The flocculants have the same graft chain distribution but the different charge densities and average grafting chain lengthes.Stone wastewater,with the characteristics of high turbidity,was taken as the target pollutant,and the effects of structural factors(the length of grafted chains and charge density)and environmental factors(flocculant’s dosage and pH,etc.)on the flocculation performance of St-Gs were discussed in detail.The flocculation mechanisms were explored and discussed on the basis of the changes in the zeta potentials of supernatant after flocculation,the dynamic results of the flocs properties and the theoretic analysis from the extended DLVO theory.The experimental findings show that St-Gs have better flocculation performance than a traditional inorganic coagulant,polyaluminum chloride.The efficient turbidity removal by St-Gs in stone wastewater is mainly ascribed to the charge patching mechanism and also to the synergistically bridging effect.With the increase of charge density in St-Gs,the turbidity removal rate increases while the optimal flocculant dosage decreases,and also the recovery coefficient after flocs breakage increases.Nevertheless,the size,growth rate,and strength coefficient of flocs are positively correlated with the average length of graft chain in St-Gs.The results of the extended DLVO theory illuminate that the total interaction energy between St-Gs and colloidal particles in stone wastewater is negative,and also negatively correlated with the charge density of St-Gs.St-G1 with the highest charge density in all the St-G samples has the lowest to

关 键 词：石材废水 阳离子接枝改性淀粉絮凝剂 结构因素 絮凝性能 絮体性质 扩展DLVO理论 絮凝机制 

分 类 号：X703[环境科学与工程—环境工程]