A review of nano-based materials used as flocculants for water treatment

In recent years, the development of nanoparticle materials for water treatment has received great attention. From an industrial technological view point, the application of nanomaterials in the twenty-first century for water treatment will be the focal point of advanced materials design, processing and progress. In this context, the potential utilisation of different types of flocculants to clean up contaminated water becomes important to address the tremendous increase of water pollution resulting from continued high-level global industrialisation. A number of researchers have investigated the effectiveness of various nanoflocculants for this purpose. Although these nanoflocculants have been reported to successfully treat contaminated water, their flocculation performances are different. To the best of our knowledge, there is no review article which summarises the application and performance of nanoflocculants in the treatment of water containing various types of contaminants. This review summarises the recent development of a wide range of nanoflocculants for the treatment of water polluted particularly by heavy metals, dyes and bacteria. The influence of physicochemical properties of nanoflocculants upon their performance and optimum flocculation conditions is discussed in detail. This review will provide a useful source of information for researchers working on the advancement of cost-effective and environmentally friendly nanoflocculants.