www.advmatinterfaces.de 2100533 (1 of 9) © 2021 Wiley-VCH GmbH RESEARCH ARTICLE Aminoclay-Graphene Oxide Composite for Thin- Film Composite Reverse Osmosis Membranes with Unprecedented Water Flux and Fouling Resistance Md Rabiul Islam, Pratishtha Khurana, Pillalamarri Srikrishnarka, Ankit Nagar, Madhuri Jash, Shantha Kumar Jenifer, Mohd Azhardin Ganayee, Mathava Kumar,* and Thalappil Pradeep* DOI: 10.1002/admi.202100533 (RO) has emerged as a promising method to eradicate the drinking water crisis. [1–7] An RO membrane generally consists of a polyester non-woven fabric upon which a polysulfone layer is casted. These two layers are porous, highly permeable, and provide mechanical support to the top- most layer. The polysulfone side of the membrane is coated with a cross-linked aromatic polyamide thin flm by interfa- cial polymerization between the organic molecules (e.g., trimesoyl chloride, TMC) and aqueous (e.g., m-phenylene diamine, MPD) phases. [8–11] The presence of the active layer of polyamide improves the salt rejection, and antifouling properties of the membrane. [11,12] Additives including cam- phor sulfonic acid (CSA), triethylamine (TEA), and sodium lauryl sulfate (SLS) are also frequently used to enhance the mem- brane preparation by aiding the absorption of MPD on the polysulphone support. [12] Despite copious advantages of mem- brane fltration systems, such as easy opera- tion and high fexibility in technologies, they present some limita- tions, including chlorine sensitivity, and susceptibility to fouling, which impedes their large-scale applications. [13–15] In some cases, deposition of extra-cellular polymeric substances (EPS), soluble microbial products (SMP), and microbial cells in the pores resulting in a drop in fux and salt rejection capacity. The amide groups in the polyamide skin layer are also vulnerable to chlorine attack, even at a low chlorine dosage in the feed water. [16] The polyamide chains allegedly undergo ring chlorination in the presence of chlorine, which disrupts hydrogen bonding between the chains and degrades the polymer matrix. [17] The disruption leads to a dramatic decline in the permeation fux, membrane life, and selectivity, which increases the required pressure for operation. Modifcation of the thin-flm composite (TFC) membranes by adding diferent hydrophilic nanoma- terials like carbon, alumina, silica zeolites, 2D materials, and their derivatives is common in order to combat these prob- lems and improve water permeation characteristics. [8,18–28] Recently, several nanocomposites-based RO membranes have been explored extensively, as synergy of components enhances the physicochemical properties and increases thermal and Present work attempts to incorporate aminoclay-graphene oxide compos- ites into thin-flm composite (TFC)-reverse osmosis membranes to improve the desalination efciency of brackish water. The composite is coated on a polysulfone substrate as a result of interfacial polymerization of m-phenylene diamine and trimesoyl chloride, at diferent time durations. The prepared membranes are analyzed for their water permeation and salt rejection ef- ciencies using brackish feed water. The results indicated that the membrane loaded with 0.015 wt% of the composite delivered maximum fux at 20 bar pressure for 2000 ppm feed. Moreover, the water fow rate increased by ≈3.27 times (from 15.62 ± 0.36 to 50.28 ± 1.69 Lm –2  h –1 ), compared to the unmodi- fed TFC membrane. An enhancement in the salt rejection from 97.03 ± 1.07 to 99.51 ± 0.10% is also observed for the same feed water at 20 bar as compared to the unmodifed membrane. Furthermore, antifouling tests with model bio-foulant humic acid revealed better stability and antifouling performance of the prepared membranes than the unmodifed membranes under identical operating conditions. The membrane, therefore, assures high performance and lifetime owing to its mechanical and chemical stability, and hence sug- gests energy-efcient desalination. M. R. Islam, P. Khurana, P. Srikrishnarka, A. Nagar, M. Jash, S. K. Jenifer, M. A. Ganayee, M. Kumar, T. Pradeep DST Unit of Nanoscience (DST UNS), and Thematic Unit of Excellence (TUE) Department of Chemistry Indian Institute of Technology Madras Chennai 600 036, India E-mail: pradeep@iitm.ac.in M. Kumar Environmental and Water Resources Engineering Division Department of Civil Engineering Indian Institute of Technology Madras Chennai 600 036, India E-mail: madhav@iitm.ac.in The ORCID identifcation number(s) for the author(s) of this article can be found under https://doi.org/10.1002/admi.202100533. 1. Introduction Water is the world’s most precious resource, essential for the functioning of all life forms. Desalination using reverse osmosis Adv. Mater. Interfaces 2021, 2100533