Smart Covalent Organic Frameworks as a dual-role material for light-controlled colorimetric pH detection and efficiency removal of pollutants in water treatment

Abstract Covalent Organic Frameworks (COFs) with uniform aperture size, high surface area and tunable structure have been proposed as a potential material in water treatment. In this work, we prepared methoxy based covalent organic frameworks (COF-OMe) at room temperature as a dual-role smart material. For one thing, it can respond to the pH of solutions by visual, colorimetric change. Due to the protonation effect, the fluorescent intensity of COF-OMe went down and the color changed from yellow to black as the pH decreased reversibly. For another, the light-triggered oxidase-mimic porous COF-OMe can be applied in the synergistic removal of organic pollutants with high efficiency and great recovery. The prepared COF-OMe realize the rapid, visual pH detection and pollutants aggregation when light’s off before treatment, then efficient removal of pollutants with light irradiation. The outstanding and sensitive response to pH, great removal efficiency and light-controlled dual function made it applied in water treatment with great potential, achieving killing two birds with one stone.