Nanomaterials for biofouling and scaling mitigation of thin film composite membrane:A review

Biofouling and scaling are commonly encountered bottlenecks in large and small scale installations of membrane technology for surface-, waste- or seawater treatment. The phenomena can pose persistent operational challenge with substantial economic impacts if they are left unresolved. Effort has been made to reduce the tendency of these detrimental phenomena by improving membrane properties, optimizing operational conditions as well as establishing reliable pretreatment of the feed water. This review places a main focus on the recent advances of low biofouling and scaling thin film composite (TFC) membranes that are incorporated with different types of nanomaterials. In this contribution, the biofouling and scaling phenomena and their negative effects on TFC membranes are first discussed. The recent studies on the preparation of low biofouling and anti-scaling TFC membrane using different nanomaterials are then critically summarized. Current challenges to enhance membrane long-term stability, reliability, and cost efficiency are also highlighted. The applications of nanomaterials in membrane desalination are anticipated to improve resistance properties of TFC membranes against biofouling and scaling and further foster the innovation of sustainable membrane desalination technology. © 2016 Elsevier B.V. All rights reserved.

The development of new generation of TFC membranes with the incorporation of nanomaterials can address the environmental impacts posed by current conventional desalination. The nanocomposite membrane that can maintain or perhaps outperform the existing conventional membrane is pivotal for the sustainability of desalination industries. This review focuses on the development of new generation of TFC membrane in the past decade and it is clear that more work and research are focusing on the understanding the dynamics of nanomaterials and their performance in desalination. In the previous discussion, we found that there are many factors that could affect the biofouling and scaling on membrane surface, which range from system operating parameters to membrane surface properties. Numerous studies have shown that membrane surface properties such as hydrophobic/ hydrophilic properties, membrane surface charge (zeta potential) and surface roughness, characteristics of feed solution including ionic strength and pH as well as the system operating conditions including pressure, temperature, flow velocity and concentration polarization, are critical to these fouling phenomena because they determine the interaction between the membrane and the foulants. The surface modification of the PA layer of TFC membrane using different nanoparticles has shown remarkable enhancement to the antifouling properties of unmodified TFC membrane. Despite the significantly greater achievements, there are still some challenges encountered during fabrication process of new generation of TFC membrane. These include membrane long term stability, reliability, economic feasibility, poor dispersion of these nanomaterials within the PA layer, lack of chemical interaction between nanomaterials and organic PA layer as well as alignment control of nanotubes in PA layer. Thus, it is necessary to develop more advanced/novel nanomaterials with specific surface properties that could readily disperse well in non-polar solvent and/or to achieve homogenous distribution of the nanomaterials in PA layer. Nevertheless, it is worth to highlight that the development of strong antifouling composite membranes using different nanomaterials to tailor the membrane surface properties while optimizing the operation conditions, feed pre-treatment and cleaning process. Undoubtedly, membrane fouling problem can be greatly suppressed to extend the effectiveness and long term performance of the membrane. Overall, it is worth noting that dedicated scientific investigation on TFC antifouling properties has accelerated during the past decade. With ongoing research, it is possible that more advancements and more conclusive findings can be noted in the coming years, especially in the areas of economic and environmental sustainability.