Inorganic scaling in reverse osmosis (RO) desalination: Mechanisms, monitoring, and inhibition strategies

With decades of developments, RO desalination has evolved into a mature technology with excellent performance to meet emergent global freshwater needs. Nevertheless, the economic effectiveness, ecological and environmental friendship have evolved into the concerns being paid great attention with the shift of focus in recent years. In RO process, the concentrated brine was always discharged, which is unfavorable for economical effectiveness and also might bring potential damage to ecology and environment. Increasing recovery rate is an effective strategy that could decrease brine discharge, enhance environmental friendship and economic benefit. However, increasing recovery rate is encountered with inorganic scaling, which is induced by supersaturation of mineral ions due to the continuously increasing concentration. Inorganic scaling would block membranes, dramatically decrease permeations, and even interrupt engineering operation. Thus, enhancing the anti-scaling capability of RO desalination is vitally important. In this review paper, state-of-the-art developments of anti-scaling strategies in RO desalination are analyzed combined with comments and prospective. It is expected that the contents in this paper could offer an insight in deeper understanding the scaling in RO desalination and provide some clues for exploring more advanced anti-scaling technologies, and thereby increase the economic benefit of RO desalination and enhance their environmental friendship.