Aloe barbadensis miller-based metallic composites for photocatalytic degradation of reactive and cationic dyes and antimicrobial applications

Abstract

Due to the synergistic effect of the two metals, bimetallic nanoparticles have attracted a lot of attention by boosting their properties as compared to monometallic nanoparticles. Herein, for the first time, bimetallic copper-chromium (Cu–Cr@BMNPs) nanoparticles using Aloe Vera extract (as a capping and reducing agent) were prepared via a hydrothermal approach. The prepared nanoparticles capped with organic moieties and antibacterial activity were employed in wastewater treatment. The calculated z-average size was 200–250 nm, which proved the formation of particles in the nano-range, while a point of zero charge was attained at pH 8.2. The results of band gap energy revealed that Cu–Cr@BMNPs have less energy band gap than monometallic nanoparticles. Digital images of Scanning electron microscopy clearly illustrate irregular and porous surfaces of synthesized particles, while purity of the sample was confirmed through X-ray diffraction spectrum. Synthesized Cu–Cr@BMNPs were used to degrade Reactive Black (RB) and Malachite Green (MG) dyes. The maximum degradation of RB was 85 % at pH 3, catalyst dose of 15 mg, dye concentration of 25 ppm, and exposure time of 60 min. For MG, the maximum degradation of 97 % was observed at pH 8, catalyst dose 20 mg, dye concentration 25 ppm, and time 60 min. Among different kinetic models, the Behnajady-Modirshahla-Ghanbery model was best fitted to the experimental data. Prepared BMNPs showed promising inhibition in the growth of two tested strains E. coli and Staph aureus with a zone of 8 mm. Therefore, Cu–Cr@BMNPs were found to be a promising tool for photocatalytic degradation of dyes as well as antibacterial agents.