Fabrication of visible light-excited photocatalytic TiO2 nanocomposite membranes for removal of organic pollutants and pathogenic microorganisms

虽然大多数加拿大人可以获得处理过的水，但许多第一民族和其他偏远和农村社区仍然面临着获得清洁饮用水的挑战。这些沃茨经常受到农用化学品和污水的污染，为微生物的生长提供了一个营养丰富的培养基，对人类健康构成了巨大的危险。鉴于全球的水处理需求，开发可脱离电网部署的具有成本效益的水处理装置将是非常可取的。膜技术已被广泛应用于饮用水处理，然而，生物污垢和高运行成本仍然是实施的重大障碍。用各种金属和非金属材料增强的TiO 2纳米复合膜可以拓宽可见光的光谱，用于驱动有机污染物和病原微生物的光催化降解;这样的系统将是一种简单但具有成本效益的水处理方法。** 目前，有两种策略用于合成可见光激发的TiO 2纳米材料。第一种是将TiO 2与其他可见光敏化的纳米材料如CdS纳米颗粒、贵金属纳米颗粒（即AgNP和AuNP）和染料分子偶联，以缩小它们的带隙;然而，所有已发表的工作都是针对TiO 2纳米颗粒的，没有用TiO 2纳米线完成的工作。这些纳米线膜表现出明显的优势，超过传统的二氧化钛纳米粒子的方法，其中额外的能量消耗在回收的纳米粒子，这是由于后处理去除的限制，本身可能会污染最终处理的水。另一种策略是在TiO 2纳米线的合成过程中掺杂金属元素（Fe、Mo、Ru、Os、Re、V和Rh）或非金属元素（C、S、N、I），但这种方法的效率还有待证明。为了去除环境污染物或病原微生物，仅进行了初步尝试，以评估UV光的抗微生物和抗病毒衰减。**我们期望开发一种高效的“绿色”清洁技术（基于掺杂的TiO 2纳米线和TiO 2与金和银纳米线、碳纳米材料、LDH的复合物），使用太阳光作为能源。我们还建议开发一种综合水处理装置，适用于城市和偏远的低资源地区的单一家庭使用。迄今为止，我们的团队在制造和评估TiO 2膜在紫外光下降解有机污染物的功效方面拥有相当丰富的经验。此外，还对TiO 2纳米颗粒与生物分子（如DNA）的相互作用进行了机理研究，为TiO 2如何与生物系统相互作用提供了新的见解。 这些知识可以转移到制造DNA-TiO 2纳米膜的污染物的浓度和去除。 *****************

While most Canadians enjoy access to treated water, many First Nations and other remote and rural communities still face challenges with accessing clean drinking water. Frequently, such waters are contaminated with agrichemicals and sewage, providing a nutrient-rich medium for the growth of microorganisms posing a huge risk to human health. Development of cost-effective water treatment devices deployable off the electrical grid would, in light of water treatment needs globally, be highly desirable. Membrane technologies have been extensively ultilized in drinking water treatment; however, biofouling and high operating costs remain significant barriers for implementation. TiO2 nanocomposite membranes augmented with a variety of metallic and non-metallic materials can broaden the spectrum of visible light harnessed to drive photocatalytic degradation of organic contaminants and pathogenic microorganisms; such a system will be a simple but cost-effective means of treating water. ******Currently, there are two strategies for synthesis of visible light-excited TiO2 nanomaterials. The first is to couple TiO2 to other visible light sensitized nanomaterials such as CdS NPs, noble metal nanoparticles (i.e. AgNPs and AuNPs), and dye molecules, to narrow their band gap; however, all published work has been for TiO2 nanoparticles, with no work completed with TiO2 nanowires. These nanowire membranes demonstrated distinct advantages over traditional TiO2 NP approaches, where additional energy is consumed in recycling the nanoparticles, which due to post-treatment removal constraints, may themselves contaminate the final treated water. Another strategy is doping with metallic (Fe, Mo, Ru, Os, Re, V, and Rh) or non-metallic elements (C, S, N, I) during the synthesis of TiO2 nanowires, but the efficiency of this approach is yet to be proven. For the removal of environmental contaminants or pathogenic microorganisms, only initial forays were taken to evaluate anti-microbial and anti-viral attenuation with UV light.******We expect to develop an efficient and effective "green" clean technology (based on doped TiO2 NWs and TiO2 composites with gold and silver nanowires, carbon nanomaterials, LDH) using solar light as the energy source. We further propose the development of an integrated water treatment device, suitable for single family use, in both urban and remote low-resource areas. To date, our group has considerable experience fabricating and evaluating the efficacy of TiO2 membranes towards the degradation of organic contaminants under UV. In addition, a mechanistic study on TiO2 NPs interaction with biomolecules (such as DNA) has been performed, providing new insight into how TiO2 interacts with bio-systems. This knowledge can be transferred to fabricate DNA-TiO2 nanomembranes for pollutant concentration and removal. *****************