Today,due to industrialization, population growth and climate change, water is increasinglypolluted which is one of the most serious global challenges and needs to beurgently solved 1,2. Out of total earth’s water, only around 0.8% is freshwater. Thus numerous researches have been conducted in an effort to establishmore sustainable technological solutions that would meet increasing waterconsumption 3–6.Desalinationis the process of removing salts or other minerals and contaminants fromseawater, brackish water, and wastewater effluent and it is an increasinglycommon solution to obtain fresh water for human consumption and fordomestic/industrial utilization. Desalination technologies can be classified bytheir separation mechanism into thermal and membrane based processes. Thermaldesalination separates salt from water by evaporation and condensation and includesmultistage flash (MSF), multiple effect distillation (MED), and vapor compression(VC).
In membrane desalination, water diffuses through a membrane, while saltsare almost completely retained and includes reverse osmosis (RO) andelectrodialysis (ED) 7–13.Whilethermal desalination has remained the primary technology of choice in theMiddle East due to easily accessible fossil fuel resources and the poor waterquality of the local feed water, RO membrane processes have rapidly developedand now surpass thermal processes in new plant installations 3, 14–16. In globaldesalination capacity by process, RO has maximum 53% of capacity share 17.Dueto environmental impact, treatment of industrial effluents and waste waterbecomes necessary. Using membrane in water cleaning process has significantadvantage therefor membrane technology become popular in industrial watertreatment. Membrane technology are modular which is easy to scale up, simple inoperation, relatively low energy consumption, no chemical additives, etc.
18–21. Separation with membranes occurs because of the existence of agradient across the membrane, and membrane processes may be divided into groupsbased on the specific type of gradient. The most common way of categorizing membranesis to divide them into two groups: non-pressure driven and pressure driven. Innon-pressure driven membrane processes, the driving forces are concentrationgradient (such as gas separation and pervaporation), temperature gradient(membrane distillation), and electrical potential gradient (electrodialysis).The pressure driven process having mainly four groups as per the size ofparticle they retain: microfiltration (MF), ultrafiltration (UF),nanofiltration (NF), and reverse osmosis (RO) 22–27.PolyamideRO membranes are the major technology for clean water supply, but the mainbarrier for universal application of these membranes is fouling.
Also, these ROmembranes are vulnerable to chlorine. These two factors can deteriorate membranespermeability, decrease in salt rejection, rising in energy consumption andshortening life of membranes. In this paper, surface modification of polyamideTFC RO membrane to improve fouling resistance and performance of membrane isreviewed over the years.