Preparation of Cotton Linters’ Aerogel−Based C/NiFe2O4 Photocatalyst for Efficient Degradation of Methylene Blue

Abstract

At present, the research focus has been aimed at the pursuit of the design and synthesis of catalysts for effective photocatalytic degradation of organic pollutants in wastewater, and further exploration of novel materials of the photodegradation catalyst. In this paper, the Sol−gel route after thermal treatment was used to produce NiFe2O4 carbon aerogel (NiFe2O4−CA) nanocomposites with cotton linter cellulose as the precursor of aerogel, by co−precipitating iron and nickel salts onto its substrate. The structure and composition of these materials were characterized by X−ray diffraction (XRD), energy dispersive spectroscopy (EDS), Raman spectra, high−resolution scanning electron microscopy (HR−SEM), high−resolution scanning electron microscope mapping (SEM−mapping), X−ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET)’s surface area. The magnetic properties of the material were analyzed by a vibrating−sample magnetometer (VSM). Moreover, diffuse reflectance spectra (DRS), electrochemical impedance spectroscopy (EIS) and photo−luminescence spectroscopy (PL) characterized the photoelectric properties of this cellulose−aerogels−based NiFe2O4−CA. Methylene blue (MB) acted as the simulated pollutant, and the photocatalytic activity of NiFe2O4−CA nanocomposites under visible light was evaluated by adjusting H2O2 content and the pH value. The results showed that the optical absorption range of nickel ferrite was broadened by doping cellulose−aerogels−based carbon, which exerted more positive effects on photocatalytic reactions. This is because the doping of this aerogel carbon promoted a more uniform distribution of NiFe2O4 particles. Given the Methylene blue (MB) degradation reaction conformed to the first−order kinetic equation, the NiFe2O4−CA nanocomposites conducted excellent catalytic activity by maintaining almost 99% of the removal of MB (60 mg/L) within 180 min and upheld excellent stability over four consecutive cycles. This study indicated that NiFe2O4−CA nanocomposites reserved the potential as a future effective treatment of dye wastewater.