ABSTRACT
Tungsten oxide nanostructures were modified by oxygen vacancies through hydrothermal treatment. Both the crystalline structure and morphological appearance were completely changed. Spherical WO3·H2O was prepared from tungstic acid solution by aging at room temperature, while rod-like WO3·0.33H2O was prepared by hydrothermal treatment of tungstic acid solution at 120 °C. These structures embedded in sodium alginate (SA)/polyvinylpyrrolidone (PVP) were synthesized as novel porous beads by gelation method into calcium chloride solution. The performance of the prepared materials as photocatalysts is examined for methylene blue (MB) degradation in aqueous solutions. Different operation parameters affecting the dye degradation process, such as light intensity, illumination time, and photocatalyst dosage are investigated. Results revealed that the photocatalytic activity of novel nanocomposite changed with the change in WO3 morphology. Namely, the beads with rod nanostructure of WO3 have shown better effectiveness in MB removal than the beads containing WO3 in spherical form. The maximum degradation efficiency was found to be 98% for WO3 nanorods structure embedded beads, while the maximum removal of WO3 nanospheres structure embedded beads was 91%. The cycling-ability and reuse results recommend both prepared structures to be used as effective tools for treating MB dye-contaminated wastewaters. The results show that the novel SA/PVP/WO3 nanocomposite beads are eco-friendly nanocomposite materials that can be applied as photocatalysts for the degradation of cationic dyes in contaminated water.
ABSTRACT
The presence of pharmaceutical residues in aquatic environments represents a risk for the equilibrium of the ecosystem and may seriously affect human safety itself in the long term. To address this issue, we have synthesized functional materials based on highly-reduced graphene oxide (HRGO), sulfonated graphene (SG), and magnetic sulfonated graphene (MSG). The method of synthesis adopted is simple and inexpensive and makes use of plastic bottle waste as the raw material. We have tested the fabricated materials for their adsorption efficiency against two model antibiotics in aqueous solutions, namely Garamycin and Ampicillin. Our tests involved the optimization of different experimental parameters of the adsorption process, such as starting antibiotic concentration, amount of adsorbent, and time. Finally, we characterized the effect of the antibiotic adsorption process on common living organisms, namely Escherichia coli DH5α (E. coli DH5α) bacteria. The results obtained demonstrate the efficiency of the method in addressing the issue of the emergence of antibiotic-resistant bacteria, which will help in preventing changes in the ecosystem.
ABSTRACT
Numerous of pollutants threaten our planet, for instance plastic wastes causes a huge potential risk on the environment in addition to many of emergened pollutants as pharmaceutical residue in aquatic environments which affecting ecological balance and in-turn affecting human health. Accordingly, this research proposed an innovative facile, one-step synthesis of functionalized magnetic fullerene nanocomposite (FMFN) via catalytic thermal decomposition of sustainable poly (ethylene terephthalate) bottle wastes as feedstock and ferrocene as a catalyst and precursor of magnetite. Growth mechanism of FMFN was discussed and batch experiments were achieved to examine its adsorption efficiency in relation to Ciprofloxacin antibiotic. Different adsorption parameters including time, initial Ciprofloxacin concentration, and solution temperature were investigated and optimized using Response Surface Methodology (RSM) model. In addition, a study on the antibiotic adsorption process impact on the organisms of an ecosystem was conducted using E. coli DH5α, and results validated method's efficiency in overcoming problem of appearance of antibiotic-resistant microbes.
