Optimized Degradation of Eosin Dye Through UV-ZnO NPs Catalyzed Reaction

Development of sustainable strontium ferrite graphene nanocomposite for highly effective catalysis and antimicrobial activity

Graphene oxide (GO) has layered structure with carbon atoms that are highly coated with oxygen-containing groups, increasing the interlayer distance while simultaneously making hydrophilic atomic-thick layers. It is exfoliated sheets that only have one or a few layers of carbon atoms. In our work, Strontium Ferrite Graphene Composite (SF@GOC) has been synthesized and thoroughly characterized by physico-chemical methods like XRD, FTIR, SEM-EDX, TEM, AFM, TGA and Nitrogen adsorption desorption analysis. A very few catalysts have been manufactured so far that are capable of degrading Eosin-Y and Orange (II) dyes in water by heterogeneous catalytic method. The current study offers an overview of the recyclable nanocomposite SF@GOC used in mild reaction conditions to breakdown the hazardous water pollutant dyes Eosin-Y (96.2%) and Orange (II) (98.7%). The leaching experiment has demonstrated that the use of the transition metals strontium and iron have not result in any secondary contamination. Moreover, antibacterial and antifungal assay have been investigated. SF@GOC has shown greater activity with bacterial and fungal species while compared with GO. FESEM analysis shows that the bactericidal mechanism for SF@GOC is same in both gram-negative bacteria. The difference in the antifungal activity among the candida strains can be correlated with the movement of ions release (slower and faster) of synthesized nanoscrolls in SF@GOC. In comparison to previous reports, this new environmentally safe and novel catalyst showed substantial degrading activity. It can also be applied to new multifunctional processes such as in the fields of composite materials, solar energy, heterogeneous catalysis and biomedical applications.

Optimization Study on Synergistic System of Photocatalytic Degradation of AR 26 and UV-LED Heat Dissipation

In this work, a novel UV-LED/TiO2 photocatalytic system, having a single layer with ten LED beads, was designed to simultaneously achieve UV-LED cooling and wastewater degradation, to deal with heat dissipation problems of high-power UV-LEDs. To gain more insight into this system, the parameters affecting both cooling and photocatalytic performance were first optimized using AR 26 as a basis. With respect to sewage, sewage with a flow rate of 80 mL/min and a temperature of 20 °C helped to keep a lower temperature of UV-LED, which benefits the long-term operation stability of LED beads. For parameters affecting the photocatalytic performance only, the experiments showed that TiO2 with moderate dosing (0.75 g/L) under strong acid conditions (pH = 2) helped to further improve photocatalytic activity when the initial concentration of AR 26 was 45 mg/L. Lastly, to illustrate the advantages of this novel system, the performance of the synergistic system was compared with a conventional photocatalytic reactor with respect to degradation performance, optical quantum efficiency, and energy consumption. The results showed that the degradation efficiency and light source utilization ratio of this coupled system were, respectively, 2.1 times and 1.5 times as much as those of a conventional reactor. As the unit power consumption of the synergistic system was only 0.18-fold more than that of a conventional reactor, our work suggests that this synergistic system with the advantage of LED lamp beads has a bright future in dealing with refractory organic pollutants of sewage.

Degradation of Toxic Dye and Antimicrobial and Free Radical Potential of Environmental Benign Zinc Oxide Nanoparticles

Several industries have become major contributors to waterbody contamination due to the improper removal of dyes and effluents into water bodies. Due to their carcinogenic properties and low biodegradability, dye degradation is a considerable danger to people, animals, and the oceanic environment. As part of this study, Andrographis paniculata leaf extract was used as a reducing and stabilizing agent to synthesize zinc nanoparticles and degrade dyes such as methyl red and eosin. Zinc oxide nanoparticles (ZnONPs) showed a surface plasmon resonance peak at 430 nm in the UV spectrum. The FTIR result showed a band at 597.93 cm-1 that confirmed the formation of zinc nanoparticles. AFM results revealed spherical ZnONPs. The SEM results predicted an average particle size of 60 nm for crystalline particles. Biologically synthesized zinc nanoparticles exhibited greater antibacterial activity against Pseudomonas spp. and Proteus spp. but lesser activity against Klebsiella spp. and S. aureus. At 1000 μg/ml concentration, ZnONPs had the highest antioxidant activity of 45.34%. An ultraviolet-visible spectrophotometer measured dye degradation progress between 300 and 800 nm. For methyl red, the maximum absorption peak was measured at 415 nm, and for eosin, the maximum peak value was measured between 500 and 515 nm.