【作者】 田华；

【导师】 李东亮；

【作者基本信息】 西安建筑科技大学 ， 应用化学， 2011， 硕士

【摘要】 近年来环境污染严重,水体的污染严重影响了人类生存环境及人体安全,水体净化和消毒是环境保护中一项重要的工作。对于可饮用水体的消毒,传统工艺方法均暴露出或多或少的缺点与不足。因此将传统抑菌技术与膜技术相结合,制备复合型的抑菌材料,对饮用水体的抑菌和净化等环境保护工作,具有广阔的研究空间和发展前景。本文针对二次饮用水系统中经常出现微生物超标并且储水设备清洁不彻底或者被忽略的情况,以壳聚糖（CTS）和聚乙烯吡咯烷酮共混物（PVP）为膜基体,添加Ag（Ⅰ）和纳米TiO₂悬浮液,用溶胶法制备了Ag/CTS/PVP共混膜、Ag/TiO₂/CTS/PVP共混膜及Ag-TiO₂/CTS-PVP抑菌颗粒材料。实验考察了两种膜及颗粒材料对大肠杆菌的抑菌性能影响以及CTS含量、PVP含量、热处理时间、Ag（Ⅰ）浓度、纳米TiO₂浓度等因素对抑菌材料抑菌性能的影响。利用FT-IR对Ag（Ⅰ）/TiO₂/CTS/PVP膜中Ag（Ⅰ）和活性基团之间的结合机理做了初步探讨,借助SEM和EDS对膜表面形貌进行表征,同时还考察了抑菌共混膜和抑菌颗粒材料的理化性能,包括机械强度、含水率、热稳定性以及材料的抑菌性能和持久使用性等。通过正交实验确定了制备具有较优抑菌性能的Ag/TiO₂/CTS/PVP共混膜的最佳条件,当ρ（Ag（Ⅰ））=0.08%,ρ（CTS）=2.25%,ρ（PVP）=3.00%,ρ（TiO₂）=0.20%时,共混膜的抑菌圈可达到23.1 mm;控制反应温度为60℃、时间为120 min进行热处理,得到的Ag/TiO₂/CTS/PVP的干、湿态共混膜均具有较好的拉伸强度;采用低浓度的NaOH溶液进行碱处理可以使膜完整脱除并具有一定的韧性和机械强度,同时该过程不影响Ag（Ⅰ）和功能单体间的结合;通过共混膜CTS/PVP、TiO₂/CTS/PVP和Ag/TiO₂/CTS/PVP的DSC曲线图可以看出,三者的玻璃化转变温度T_g分别为46.03℃、49.61℃、50.36℃,并且这三种曲线都只有一个玻璃化转变温度T_g,说明这三种膜的各种组份相容性都很好。由电镜可以明显观察到两种膜表面均呈现致密均匀外观,加入Ag（Ⅰ）和纳米TiO₂后可以看到二者存在于膜表面和镶嵌于膜内部。Ag-TiO₂/CTS-PVP抑菌颗粒材料在Ag（Ⅰ）初始浓度为2.0mg/mL时,60℃下经过3.0 h的热处理,具有较好的强度、韧性和抑菌性能。通过质量磨损实验以及抑菌持久性实验结果表明,位于颗粒表面的Ag-TiO₂功能层与CTS-PVP基体间具有良好的结合力。集中于颗粒材料的表层起抑菌作用的纳米Ag和TiO₂,能提高其有效利用率,强化颗粒材料的抑菌性能。用去离子水浸泡Ag/TiO₂/CTS/PVP膜,测得水中Ag（Ⅰ）浓度约为7.0μg/L,该值远小于国家水质非常规指标极限值,说明该膜在水体中稳定,不会对饮用水造成二次污染。对Ag/TiO₂/CTS/PVP膜和Ag-TiO₂/CTS-PVP抑菌颗粒材料进行抑菌持久性实验表明,经过30天浸泡后,二者抑菌率仍达到75%以上,证明这两种抑菌材料具有较好的持久抑菌性能,是一类良好的复合抑菌材料。更多还原

【Abstract】 Since environment pollution has been serious in recent years and water pollution has heavily influenced the living condition of human beings and their physical bodies, the purification and disinfection of water has become an essential part of environmental protection. As for the disinfection of potable water, the traditional technology appeared not to be good enough. Therefore, it is promising to combine the tradition bacteriostatic technology with the membrane technology for the future research and science development, so as to produce compound bacteriostatic material.This paper aims to dissolve the microbe superscale in the recycled potable water, considering the advanced antibacterial materials and the characters of terminal drinking water, our team prepared composite functional membranes Ag/TiO₂/CTS/PVP and Ag/CTS/PVP, and anti-bacterial grains Ag-TiO₂/CTS-PVP with sol method, which used chitosan as a primary material and polyvinylpyrrolidone （PVP） as an additive, and was loaded with silver nanoparticles and TiO₂ nanoparticles. Moreover, different characterization methods were used to analyze the properties of the functional membrane, such as SEM and EDS. Meanwhile, the chemical and physical properties of antibacterial materials were also investigated, such as the anti-bacterial effect, tensile strength, hydrophilicity, endurable and recycle application.The orthogonal experiment showed that optimization of prepared condition isρ（AgNO₃）=0.08%,ρ（TiO₂）=0.20%,ρ（CTS）=2.25% andρ（PVP）=3.00%, when the membrane has a good properties of antibacterial activity and tensile strength. The DSC curves shows that the membrane exhibits a favorable compatibility and heat stability. The FI-IR implies that there are hydrogen bands were formed between acetyl in PVP and hydroxyl in the solution or chitosan molecule, and–NH₂ and–OH of CTS participates in the coordination bonds with Ag. The SEM image shows that TiO₂ and Ag nanoparticles are embedded in the membrane and on the surface of it. The anti-bacterial grain materials have good antibacterial activity, toughness and tenacity when the prepared condition is C（Ag（Ⅰ））=2.0mg/mL, T=60℃, t=3.0h. The quality abrasion test and anti-microbe test show that Ag-TiO₂ layer of grains has a good coalescence with CTS/PVP base. Silver and dioxide titanium nano-particles can improve the antibacterial activity of the grain materials greatly.By the application study, it proves that the releasing Ag（Ⅰ） of Ag/TiO₂/CTS/PVP membrane in water is about 7.0μg/L, which is much less than the Abnormal Limitation of Water Quality. The antibacterial activity of CTS/PVP/Ag/TiO₂ composite functional membrane and Ag-TiO₂/CTS-PVP grain materials can reach 75% in water for one month, and they also have good recycle application.更多还原