Alkaline treatment of antifoulant PVB/SA-grafted ε-MnO2 adsorptive nanocomposite membrane for synchronous separation of pollutants from pharmaceutical effluents

Abstract

Abstract Conventional membrane filtration processes suffer from severe fouling and permeance decrement due to the accumulation of co-existing pharmaceutical pollutants in pores and valleys of the surface of membranes. Adsorptive nanocomposite (ANC) membranes possess a double function of adsorption and filtration for synchronous separation of pollutants, nevertheless, nano-leaching is a considerable challenge for their applications. Herein, a new high-performance alkali-treated PVB/SA-grafted ε-MnO2 ANC membrane was fabricated through a facile phase inversion technique, and used for synchronous separation of Cd(II) ions and tetracycline (TC) from aqueous solutions. The chemical structure, elemental characteristic, surface and cross-section morphology, surface hydrophilicity, and surface topography of the fabricated alkali-treated ANC membrane (OH-PVB/SA-ε-MnO2) were respectively investigated through FTIR, XPS, FE-SEM, water contact angle and AFM techniques. The alkaline treatment enhanced the pure water flux from 311.54 to 394.62 L/m2.h.bar, which was much higher than that for the pristine PVB membrane. The rejection rates of Cd(II) and TC by the OH-PVB/SA-ε-MnO2 membrane were respectively 98.55 and 98.73 % at pH = 6. The flux recovery ratio of 99.04, 98.66 and 97.61 % was obtained after the first, second and third successive cycles respectively. This verified the excellent antifouling performance of OH-PVB/SA-ε-MnO2 membrane that was originated from the enhancement of hydroxyl group content.