The reverse osmosis (RO) process uses a semi-permeable membrane, allowing the fluid that is being purified to pass through it, while rejecting the contaminants. RO is one of the techniques able to remove a wide range of dissolved species from water. It accounts for more than 20% of the world’s desalination capacity (Shahalam et al., 2002). RO is an increasingly popular wastewater treatment option in chemical and environmental engineering. Using appropriate RO systems to remove heavy metals have been investigated (Table 5), but these have yet to be widely applied.