Department of Chemical and Environmental Engineering and Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment (NEWT) , Yale University , New Haven , Connecticut 06511 , United States.
Acc Chem Res. 2019 May 21;52(5):1187-1195. doi: 10.1021/acs.accounts.8b00578. Epub 2019 Apr 3.
Providing access to safe drinking water is a prerequisite for protecting public health. Vast improvements in drinking water quality have been witnessed during the last century, particularly in urban areas, thanks to the successful implementation of large, centralized water treatment plants and the distribution of treated water via underground networks of pipes. Nevertheless, infection by waterborne pathogens through the consumption of biologically unsafe drinking water remains one of the most significant causes of morbidity and mortality in developing rural areas. In these areas, the construction of centralized water treatment and distribution systems is impractical due to high capital costs and lack of existing infrastructure. Improving drinking water quality in developing rural areas demands a paradigm shift to unconventional, innovative water disinfection strategies that are low cost and simple to implement and maintain, while also requiring minimal infrastructure. The implementation of point-of-use (POU) disinfection techniques at the household- or community-scale is the most promising intervention strategy for producing immediate health benefits in the most vulnerable rural populations. Among POU techniques, solar-driven processes are considered particularly instrumental to this strategy, as developing rural areas that lack safe drinking water typically receive higher than average surface sunlight irradiation. Materials that can efficiently harvest sunlight to produce disinfecting agents are pivotal for surpassing the disinfection performance of conventional POU techniques. In this account, we highlight recent advances in materials and processes that can harness sunlight to disinfect water. We describe the physicochemical properties and molecular disinfection mechanisms for four categories of disinfectants that can be generated by harvesting sunlight: heat, germicidal UV radiation, strong oxidants, and mild oxidants. Our recent work in developing materials-based solar disinfection technologies is discussed in detail, with particular focus on the materials' mechanistic functions and their modes of action for inactivation of three common types of waterborne pathogens (i.e., bacteria, virus, and protozoa). We conclude that different solar disinfection technologies should be applied depending on the source water quality and target pathogen due to significant variations on susceptibility of microbial components to disparate disinfectants. In addition, we expect that ample research opportunities exist on reactor design and process engineering for scale-up and improved performance of these solar materials, while accounting for the infrastructure demand and capital input. Although the practical implementation of new treatment techniques will face social and economic challenges that cannot be overlooked, novel technologies such as these can play a pivotal role in reducing water borne disease burden in rural communities in the developing world.
提供安全饮用水是保护公众健康的前提。上个世纪，饮用水质量得到了极大改善，特别是在城市地区，这要归功于大型集中式水处理厂的成功实施以及通过地下管网分配处理水。然而，通过饮用生物不安全的饮用水感染水传播病原体仍然是发展中农村地区发病率和死亡率的最重要原因之一。在这些地区，由于建设成本高和现有基础设施缺乏，建造集中式水处理和分配系统是不切实际的。要改善发展中农村地区的饮用水质量，就需要转变观念，采用低成本、简单实施和维护的非传统创新水消毒策略，同时尽量减少基础设施的需求。在家庭或社区层面实施即用型（POU）消毒技术是在最脆弱的农村人群中立即产生健康效益的最有前途的干预策略。在 POU 技术中，太阳能驱动的工艺被认为是该策略的重要手段，因为缺乏安全饮用水的发展中农村地区通常会接收到高于平均水平的地表阳光照射。能够有效地利用阳光来生产消毒剂的材料对于超越传统 POU 技术的消毒性能至关重要。在本报告中，我们重点介绍了利用阳光消毒水的材料和工艺的最新进展。我们描述了可以通过收集阳光产生的四种消毒剂的物理化学性质和分子消毒机制：热、杀菌紫外线辐射、强氧化剂和温和氧化剂。我们详细讨论了我们在开发基于材料的太阳能消毒技术方面的最新工作，特别关注材料的机械功能及其对三种常见水传播病原体（即细菌、病毒和原生动物）的灭活作用模式。我们的结论是，由于微生物成分对不同消毒剂的敏感性存在显著差异，应根据水源水质和目标病原体选择不同的太阳能消毒技术。此外，我们预计在这些太阳能材料的放大和性能改进的反应器设计和工艺工程方面存在大量研究机会，同时考虑到基础设施需求和资本投入。尽管新处理技术的实际实施将面临不可忽视的社会和经济挑战，但这些新技术可以在减少发展中国家农村社区的水传播疾病负担方面发挥关键作用。
