Effective Visible-Light-Driven Photocatalytic Degradation of Harmful Antibiotics Using Reduced Graphene Oxide-Zinc Sulfide-Copper Sulfide Nanocomposites as a Catalyst

Emerging strategies in the sustainable removal of antibiotics using semiconductor-based photocatalysts

In the constantly growing field of environmental sustainability, the threat of newly discovered pollutants, particularly antibiotics, has become a crucial concern. The widespread presence of these pharmaceutical substances in water sources presents a complex hazard to human health and ecological balance, requiring immediate and novel intervention techniques. Regarding this, semiconductor-based photocatalysts have appeared as promising candidates, providing a sustainable and efficient way to remove antibiotics from aquatic ecosystems. Nanomaterials can effectively and precisely break down and neutralize antibiotic compounds with high efficiency and selectivity by utilizing a complex interaction between radical reactive oxygen species and non-radical equivalents under light irradiation. Although photocatalysts have certain drawbacks, such as a limited capacity to absorb light and concerns about catalytic stability, photocatalysis outperforms other advanced oxidation processes in multiple aspects. This study focuses on summarizing recent advances in the sustainable removal of antibiotics using semiconductor-based photocatalysts. By reviewing the latest studies and sustainable technologies, this study presents new insights into the complex relationship between contaminants and catalytic degradation processes. Compared to single and binary photocatalysts, modified ternary composites were found to have superior photodegradation performance under visible light exposure. To be specific g-C3N4-based ternary photocatalysts exhibited more than 90% degradation of tetracycline and sulfamethazine antibiotics within one hour of irradiation. This study addresses the antibiotic degradation efficiency during photocatalytic processes and suggests new approaches to improve the performance and scalability for wider use in real-world situations.

g-C3N4 Modified with Metal Sulfides for Visible-Light-Driven Photocatalytic Degradation of Organic Pollutants

Graphitic carbon nitride (g-C3N4) proved to be a promising semiconductor for the photocatalytic degradation of various organic pollutants. However, its efficacy is limited by a fast electron hole recombination, a restricted quantity of active sites, and a modest absorption in the visible range. To overcome these limitations, g-C3N4-Bi2S3 and g-C3N4-ZnS composites were effectively produced utilizing a starch-assisted technique. The findings from FT-IR, XRD, EDX, XPS, BET, SEM, and TEM demonstrated that the enhanced photocatalytic activity of g-C3N4-Bi2S3 and g-C3N4-ZnS composites was primarily due to their improved photocarrier separation and transfer rates. The photocatalyst facilitated the aerobic photocatalytic degradation of colorless contaminants such as coumarin and para-nitrophenol (4-NP). For the decomposition of 4-NP, g-C3N4-Bi2S3 exhibited a maximum efficiency of 90.86% in UV light and 16.78% in visible light, with rate constants of 0.29 h-1 and 0.016 h-1, respectively. In contrast, g-C3N4-ZnS demonstrated a maximum efficiency of 100% in UV light and 15.1% in visible light, with rate constants of 0.57 h-1 and 0.018 h-1, respectively. The bioinspired synthesis combined with the modification with metal sulfides proved to considerably enhance the photocatalytic activity of g-C3N4, increasing its potential for practical applicability in environmentally friendly water treatment systems for the efficient removal of recalcitrant organic contaminants.

Photocatalytic decomposition of metronidazole by zinc hexaferrite coated with bismuth oxyiodide magnetic nanocomposite: Advanced modelling and optimization with artificial neural network

The objective of the present study was to employ a green synthesis method to produce a sustainable ZnFe12O19/BiOI nanocomposite and evaluate its efficacy in the photocatalytic degradation of metronidazole (MNZ) from aqueous media. An artificial neural network (ANN) model was developed to predict the performance of the photocatalytic degradation process using experimental data. More importantly, sensitivity analysis was conducted to explore the relationship between MNZ degradation and various experimental parameters. The elimination of MNZ was assessed under different operational parameters, including pH, contaminant concentration, nanocomposite dosage, and retention time. The outcomes exhibited high a desirability performance of the ANN model with a coefficient correlation (R2) of 0.99. Under optimized circumstances, the MNZ elimination efficiency, as well as the reduction in chemical oxygen demand (COD) and total organic carbon (TOC), reached 92.71%, 70.23%, and 55.08%, respectively. The catalyst showed the ability to be regenerated 8 times with only a slight decrease in its photocatalytic activity. Furthermore, the experimental data obtained demonstrated a good agreement with the predictions of the ANN model. As a result, this study fabricated the ZnFe12O19/BiOI nanocomposite, which gave potential implication value in the effective decontamination of pharmaceutical compounds.