季铵盐/纳米银灭活水中细菌效能研究

Inactivation efficacy of quaternized chitosan/silver nanoparticles to bacteria in water

为研发一种新型的水处理消毒材料,利用壳聚糖季铵盐对纳米银进行表面修饰,制备出具有复合抗菌能力、表面呈正电性的季铵盐/纳米银(QCS/nAg)抗菌材料.以大肠杆菌为主要目标细菌,以表面接近中性、负电性的纳米抗菌材料(聚乙烯吡咯烷酮/纳米银PVP/nAg、柠檬酸盐/纳米银Citrate/nAg)为参比,对QCS/nAg灭活水中细菌活性进行研究,并对QCS和nAg在QCS/nAg抗菌活性中的作用进行评价.此外,就抗菌剂投加量、pH和氯离子对QCS/nAg灭活大肠杆菌性能的影响进行研究.通过研究银离子的释放、QCS/nAg对细菌细胞的吸附和QCS/nAg对细菌细胞壁(膜)的破坏,对QCS/nAg抗菌机理进行初步讨论.结果表明:QCS/nAg成功合成且分散性良好,相比其他nAg抗菌材料灭活细菌效果更佳;QCS和nAg在QCS/nAg灭活细菌时发挥协同作用,QCS/nAg相比PVP/nAg,在nAg投加量以及抗水中氯离子干扰方面具有更强的优越性.QCS/nAg的抗菌机理在于强化了纳米颗粒对于细菌的吸附以及对细菌细胞壁(膜)的破坏.

In order to develop a new type of disinfection material for water treatment,a new kind of antibacterial material named quaternized chitosan/silver nanoparticles(QCS/n Ag)was prepared by using quaternized chitosan as a modifier of silver nanoparticles,which has synergetic effect and positively charged surface.To study the antibacterial performance of QCS/n Ag,neutrally charged and negatively charged nanoparticles were used as comparison to inactivate bacteria,especially Escherichia coli,in water.The function of QCS and n Ag in composite materials was evaluated.Furthermore,the antibacterial influencing factors such as material dosage,pH value,and chloride ions were studied.The antibacterial mechanism of QCS/n Ag was concluded through studying the dissolution of QCS/n Ag and the reaction between QCS/n Ag and bacteria,including adsorption and damage of cell wall(cytomembrane).Results showed that QCS/n Ag with high dispersibility was successfully synthesized and it performed better inactivation effect than other n Ag.QCS and n Ag showed synergetic effect in QCS/n Ag when treated with bacteria.Compared with PVP/n Ag,QCS/n Ag exerted superiority in dosing quantity and resistance to interference of chloride ion.The antibacterial mechanism was summarized as that QCS/n Ag strengthened the adsorption process of bacteria and the damage to the cell wall(cytomembrane).