Water scarcity will be the prime threat to the millions of the human race across the globe in the future. In the recent report of WHO, about 50% of people will sustain their livings in the water-stressed zones by 2025. As every industrial sector are demanding clean water resource, it is the high time for the development of reliable strategies to recycle the wastewater efficiently. With the conventional techniques, the supply of resources with an exponential increase in the demand is highly challenging. Hence, the alternative, sustainable, and technologically advanced wastewater treatment processes need to be employed instantaneously to compete for the pace. One such promising approach is the use of nano-sized materials with the high surface area and increased surface reactivity in the removal of pollutants from the wastewater. These nanomaterials possess unique properties than their bulk forms enabled the researchers from the various fields to exploit their use in the wastewater treatment processes. As a result, multidisciplinary researches targeting water pollution has increased manifold in recent decades. For instance, the nanomaterials assisted photo-catalysis, membrane filtration, and adsorption processes showed effective results in the removal of organic dyes, heavy metal ions, oil spills, and hydrocarbons, etc. The intrinsic physicochemical, electrical, magnetic properties, and the ease of tailor-made functionalization of nanomaterials identified them as one of the most potent candidates in the water technology. However, the specified challenges such as material toxicity, stability, recovery, fouling, etc. are existing in the use of nanomaterials and several successful innovations are prospering to counteract them in recent years. With such high intentness of these nano-sized materials, the present chapter provides a comprehensive report on the pivotal researches made on the wastewater treatment processes.

缺水将是未来全球数百万人类的主要威胁。在世界卫生组织的最新报告中，到2025年，约50％的人将在缺水地区维持生计。由于每个工业部门都需要清洁的水资源，现在是制定可靠的策略来回收废水的时候了有效率的。利用常规技术，资源的需求成指数增长是非常具有挑战性的。因此，需要立即采用替代的，可持续的和技术先进的废水处理工艺来竞争步伐。一种有前途的方法是在从废水中去除污染物时使用具有高表面积和增加的表面反应性的纳米级材料。这些纳米材料比其本体形式具有独特的性能，使来自各个领域的研究人员能够将其用于废水处理过程。结果，近几十年来，针对水污染的多学科研究不断增加。例如，纳米材料辅助的光催化，膜过滤和吸附过程在去除有机染料，重金属离子，溢油和碳氢化合物等方面显示出有效的结果。内在的物理化学，电学，磁学性质和易用性纳米材料量身定制的功能化研究表明，它们是水技术中最有力的候选人之一。但是，存在特定的挑战，例如材料毒性，稳定性，回收率，结垢等。纳米材料的使用已经存在，并且近年来成功的一些创新技术正在抵消它们。鉴于这些纳米材料的高度关注性，本章提供了有关废水处理过程的关键研究的综合报告。