Insights to antiscalants in membrane processes: Types, inhibition mechanism and influencing factors

Two major challenges in desalination technology for sustainable water supply are fouling and scaling, which refer to the accumulation of unwanted contaminants and sediments on the membrane surface. Silica, barite, calcium carbonate, and gypsum are common forms of scaling. Reduced salt rejection and water flux are the results of this scaling problem. In addition to increasing system maintenance costs, the cleaning procedures frequently use corrosive chemicals or demand a significant amount of electrical energy, which makes the desalination process more difficult. The most practical and economical way to manage membrane scaling, especially at high water recovery rates, has been found to be the inclusion of antiscalants to feed stream. Generally, antiscalants impact the bulk crystallization of scales by disrupting one or more stages of the crystallization process. In this review, the types and characteristics of antiscalants are reviewed, especially the novel and environmentally friendly antiscalants used, followed by mechanism, variables influencing effectiveness, antiscalant systems, and lastly, their applications in membrane processes are introduced. The challenges in using the antiscalant performance such as dosage, water composition, and membrane material significantly influence effectiveness, necessitating precise control and monitoring. This review shows that environmental concerns, including the potential contribution to eutrophication and persistence of non-biodegradable compounds, highlight the need for eco-friendly formulations and improved waste management strategies. Future research directions should focus on developing antiscalants with superior environmental compatibility, enhanced resistance to extreme operating conditions, and multifunctionality to address complex fouling scenarios. The adoption of advanced monitoring technologies and predictive models can further refine dosing strategies, ensuring maximum efficiency and minimal ecological impact.