Hydrothermal synthesis of cobalt substitute zinc-ferrite (Co1-xZnxFe2O4) nanodot, functionalised by polyaniline with enhanced photocatalytic activity under visible light irradiation
Md Abul Bashar, Md. Tamzid Hossain Molla, Dipesh Chandra, Md. Dipu Malitha, Md. Suman Islam, M. Safiur Rahman, Md. Shameem Ahsan
Abstract
Fabrication and development of effective visible-light-responsive photocatalysts are required to tackle critical environmental issues. The aim of this study was to develop a nanocomposite material with improved photocatalytic activity for the degradation of industrial dyes such as Reactive Orange-16 (RO-16), Reactive Blue (RB-222), Reactive Yellow-145 (RY-145), and Disperse Red-1 (DR-1) without the need for a post-separation process after use. Here we report the hydrothermal synthesis of nanodots of Co 1-x Zn x Fe 2 O 4 (x = 0.3, 0.5 and 0.7), coated with polyaniline, by in situ polymerization. The Co 1-x Zn x Fe 2 O 4 nanodots, coated with polyaniline (PANI) nanograins, facilitated optical properties by easily capturing visible light. X-ray Diffraction (XRD) patterns and Scanning Electron Microscopy (SEM) images have confirmed the single-phase spinel structure of Co 1-x Zn x Fe 2 O 4 nanodot and nano-pore size of the Co 1-x Zn x Fe 2 O 4 /PANI nanophotocatalyst. The specific surface area of the Brunauer–Emmett–Teller (BET) of the Co 1-x Zn x Fe 2 O 4 /PANI photocatalyst was determined to be 24.50 m 2 /g by multipoint analysis. The final Co 1-x Zn x Fe 2 O 4 /PANI (x = 0.5) nanophotocatalyst showed high efficiency in the catalytic degradation of toxic dyes (∼98% within 5 min), with good mechanical stability and recyclability under visible light irradiation. The nanophotocatalyst was re-used and its efficiency was largely maintained, even after seven cycles (∼82%) of degradation. The effects of various parameters, such as initial dye concentration, nanophotocatalyst concentration, initial pH of dye solution, and reaction kinetics were studied. According to the Pseudo-first-order kinetic model, photodegradation data followed the first-order reaction rate (R 2 > 0.95) of degradation of dyes. In conclusion, a simple and low-cost synthesis process, speedy degradation and excellent stability of polyaniline-coated Co 1-x Zn x Fe 2 O 4 nanophotocatalyst could be used as a promising photocatalyst for dye-wastewater treatment.