Sustainable Water Purification Using an Engineered Solvothermal Carbon Based Membrane Derived from a Eutectic System

Surface water is widely adulterated by hazardous pollutants such as dyes, pharmaceutical wastes, surfactants, heavy metals, hormones, etc. Hence, there is a necessity to develop a water treatment technology that can overcome all the major water-related problems. The conventional methods for water disinfection are very specific and expensive. The challenge is to devise a purification protocol without forming harmful byproducts, which opens up the opportunity for new technologies with efficient materials toward water treatment. The present work demonstrates a sustainable strategy for robust water purification through a powder based membrane fabricated from a highly oxygenated and Al-functionalized solvothermal carbon (Al-STC) composite. A100H/A1(OH)3 functionalized Al-STCs with improved surface acidity were prepared by a low temperature solvothermal process from a eutectic system (ES) comprising ethylene glycol (EG), choline chloride (ChoCl), glucose (Glu), and aluminum salt. The ES acts as both carbon precursor and catalyst. Attributed to the unique properties such as high surface functionality, moderately high surface area, and caterpillar-like morphology, Al-STCs were employed for the fabrication of a powder based membrane to purify water in a dead-end filtration mode. Various pollutants, for instance, dyes such as malachite green (with rejection of >99.9% and flux 1522 LMH) and methylene blue (with rejection of >99.9% and flux 885 LMH), pharmaceutical drugs such as ciprofloxacin and (with rejection of >99.9% and flux 1011 LMH) and paracetamol (with rejection of S3% and flux 1010 LMH), oxytocin hormone (with rejection of 88.6% and flux 955 LMH), surfactant CTAB (with rejection of 94.9% and flux 1436 LMH), and heavy metal [Cr(VI) with rejection of >99.9% and flux 932 LMH] were successfully removed from aqueous solution using an Al-STCs based membrane. Moreover, a membrane active surface was regenerated by simple ethanol washing and reused for five consecutive cycles without compromising the flux and rejection, thus demonstrating the utility of an Al-STC based membrane as an easy-to-use and ecofriendly membrane toward all kinds of water purification in a sustainable and affordable manner.