Super-adsorptive and photo-regenerable carbon nanotube based membrane for highly efficient water purification

Abstract

Carbon nanotube (CNT) based adsorbents have attracted extensive research interest for aqueous pollutants removal. However, such adsorbents face the problems of limited adsorption capacities and costly regeneration. Here, we report a highly adsorptive photo-regenerable CNT based multifunctional membrane with excellent self-cleaning properties via the facile vacuum filtration method, followed by FeOOH in-situ anchoring and silver-amino reaction. Various dyes (Rhodamine B, methylene blue, eosin Y and acid orange 7) and emerging contaminants (bisphenol A, amoxicillin and p-nitrophenol) were tested with the CNT based membrane. Our membrane exhibited superior adsorption performance to dyes among CNT based adsorbents reported in literature. In particular, the CNT based composite membrane displayed even better adsorption performance to cationic dyes. The adsorption capacities of the membrane for Rhodamine B and methylene blue were up to 181 and 247 mg/g, respectively. The membrane also had excellent self-cleaning and photo-regenerable properties after severe organic fouling. Our multifunctional CNT based membrane combined the features of adsorption, membrane separation, and catalytic degradation into one system, showing great promise for dye polluted wastewater purification. This study also offers a new strategy to engineer robust adsorptive, self-cleaning and regenerable membranes for wastewater treatment.