Prospect of clay-based flexible adsorbent coatings as cleaner production technique in wastewater treatment, challenges, and issues: A review

Abstract “Drink up” wastewater using adsorption technology is considered an effective tactic to switch water scarcity. A proactive environmental strategy has to be established in order to increase the environmental sustainability performance particularly in obtaining cleaner wastewater discharges as well as reducing the operating cost. The adsorption process has proven efficient in eliminating the pollutants, only if the suitable adsorbent is obtained in terms of high removal rate, high adsorption capacity, and sustainability. In this regard, an innovative low-cost adsorbent coating technology has been investigated to treat industrial wastewater. The classic form of adsorbent (powder, pellet, or bead) has been improvised in terms of its flexibility along with chemical and thermal stability in the wastewater treatment plant. The present review outlines the current research of adsorbent coating in wastewater treatment by holistically highlighting the advantages of adsorbent in a way of coating (lower energy usage, flexible design, simple yet efficient procedure, etc.). Among different adsorbents, clay-modified adsorbents have generated an innovative alternative to design flexible coatings. Moreover, it has a significant adsorption potential in dye treatment which is anticipated to demonstrate its industrial application. The use of common components in synthesizing the adsorbent coating along with the adsorption mechanism between the adsorbent and targeting pollutants have also been discussed in detail. Additionally, challenges and possible future direction on the development of flexible adsorbent coating to be handled in real wastewater treatment issues are also delineated.