A high-performance liquid chromatographic method (HPLC) with UV detection is described for determination of ceftriaxone sodium (CFX) and cefotaxime sodium (CFM) content in pharmaceutical industrial wastewater. These methods are based on the detection of these antibiotics via the formation of chelate complexes with Cu(II). The developed Liquid Chromatographic method offers symmetric peak shape, good resolution and reasonable retention time for both drugs. The removal percentage reached about 100 and 92.1% at pH 7.2 for CFX and CFM, respectively. In UV detection, the removal of the chelating antibiotics were based on forming of chelate complexes with Cu(II) which detected at λ_{max =} 253 and 244 nm for CFX and CFM, respectively. Linearity, accuracy and precision were found to be acceptable over the concentration range of 5.99–59.86 µg mL⁻¹ for CFX and 14.33–71.63 µg mL⁻¹ for CFM. The proposed method can be used for the quality control of industrial wastewater containing CFX and CFM.

Malachite green accumulation in water causes harmful effects. Biodegradation by microbes was the preferred technique used to remove dyes from wastewater. Thirty yeasts were investigated for their ability to remove 50 mg of dye and belonged to: Deboryomyces, Diutina, Papiliotrema, Rhodotorula, and Saccharomyces. Based on the decolorization index (DI) of the examined yeast on the solid medium, the decolorization activity may be classified as highest, moderate and low decolorization activity with DI 1.66-2.78, 1-1.64, and <1 respectively. Rhodotorula mucilaginosa AUMC13567, R. mucilaginosa AUMC13570, Saccharomyces cerevisiae 11688, R. mucilaginosa KR264902, S. cerevisiae C3, and Diutina rugosa AUMC13571 possess the highest decolorization percentages in broth media: 98.41%, 96.65%, 96.49%, 95.59%, 92.80%, and 92.22%, respectively. The decolorization rate is influenced by time, however, yeast cell optical density has no bearing on this rate. The Fourier Transform Infrared Spectroscopy Analysis (FTIR) results of MG before and after degradation indicate a reduction of peaks along the fingerprint region, which can be attributed to the loss of aromaticity of the metabolites, which also confirm degradation by yeast strains. The effect of malachite green dye and its degradation metabolites by five selected yeasts was studied on wheat (T. aestivum), sorghum (Sorghum bicolor), maize (Zea mays), and radish (Raphanus sativus) seed germination, and results show that the germination index of seeds in untreated malachite green solution was significantly low compared to its degradation metabolites by selected yeasts and yeast …

The predatory efficacy of tilapia Oreochromis niloticus was confirmed against the immature stages of mosquitoes including Culex pipiens. The present study evaluated the detrimental impacts of sublethal concentration of myclobutanil (1000 µg/L) and S-metolachlor (140 µg/L) pesticides for 15 days on the predatory potential of O. niloticus on larvae of Cx. pipiens. Also, effects of both pesticides on acetylcholinesterase (AChE), and certain antioxidant parameters (i.e., total antioxidant capacity [TAC] and superoxide dismutase [SOD]) in the fish were assessed. The exposure of O. niloticus to sublethal concentration of myclobutanil and S-metolachlor caused destructive effects on the predatory behavior of the fish and decreased its predation rates on mosquito larvae compared to the control. Changes in predation capacity of the predatory fish on mosquito larvae may be due to the toxic effect of these pesticides on fish’s antioxidants and AChE activity. The fish pre-exposed to both pesticides presented a significant decrease in the TAC and a significant increase in the SOD activity relative to control group, indicating the advancement of oxidative stress in the treated fish. Fishes pre-exposed to sublethal of both pesticides also showed a significant increase in AChE activity. This study suggests a threat of S-metolachlor and myclobutanil to O. niloticus health and potential as a successful indigenous predatory fish on Cx. pipiens larvae.

In this study, TiO₂ heterostructures with anatase and brookite phases, as well as oxygen vacancies, were synthesized using a modified sol-gel method and a heat treatment process. Subsequently, Au nanoparticles (Au NPs) were deposited onto TiO₂ through photo-deposition. Detailed structural and chemical analyses verified the successful creation of anatase-brookite phases, efficient incorporation of Au NPs, and strong interactions between the Au NPs and the oxygen vacancies on the TiO₂ surface. Spectroscopic analysis revealed the presence of localized surface plasmon resonance (LSPR) from the Au NPs, indicating enhanced light absorption properties. The photocatalytic efficiency of the Au-TiO₂ composites was evaluated under solar light irradiation for the conversion of o-phenylenediamine to 2-methylbenzimidazole and hydrogen (H₂) production. Notably, the 2 % Au-TiO₂ catalyst achieved a remarkable 99.7 % conversion rate of o-phenylenediamine, with 90 % selectivity toward 2-methylbenzimidazole and the highest H₂ production rate within 9 h, significantly outperforming 2 % Au/UV100 (commercial TiO₂), 2 % Pd/TiO₂, and pure TiO₂. This enhanced photocatalytic performance is attributed to increased surface acidity (from both Lewis and Brønsted acid sites), efficient charge separation, increased photocurrent, reduced charge transfer resistance and the synergistic interactions between Au NPs and surface oxygen vacancies in TiO₂. These findings highlight the potential of Au-TiO₂ heterostructures for advancing solar-driven catalytic applications, promoting both clean energy generation and efficient organic transformations.

Designing efficient TiO₂-based composites for photocatalytic H₂ production from H₂O is a forward-looking aim in research; however, the lack of sufficient active sites still necessitates the addition of noble-metal cocatalyst. Herein, we report a protocol for synthesizing a ternary photocatalyst based on TiO₂, carbon dots (CDs), and either carbon nanotubes (CNTs) or reduced graphene oxide (rGO), denoted as CDs/TiO₂/CNTs and CDs/TiO₂/rGO, and their application in photocatalytic H₂ generation. After optimizing the contents of CDs, CNTs, and rGO in the composites, the CDs/TiO₂/CNTs and CDs/TiO₂/rGO photocatalysts achieved H₂ generation rates of 9082 and 2398 µmol•g⁻¹•h⁻¹, representing 44-fold and 12-fold enhancements compared with bare TiO₂, respectively. Interestingly, the synthesized ternary photocatalysts demonstrated significantly higher photocatalytic activity compared to their binary photocatalysts, TiO₂/CNTs, TiO₂@CDs, and TiO₂/rGO. Additionally, The CDs/TiO₂/CNTs composites showed excellent structural and catalytic photostability. The incorporation effect of carbon dots (CDs) was further explored through optical and photoelectrochemical measurements, which revealed that CDs act as electron mediators, facilitating charge transfer and transport. These findings highlight the potential of carbon dots in improving the performance of TiO₂-based composites for sustainable hydrogen production and provide insights into the design of advanced composites for photocatalytic applications.

This study presents the green synthesis and characterization of NiFe₂O₄@CdS core-shell nanocatalysts for enhanced photocatalytic sustainable hydrogen production. An eco-friendly approach was adopted to fabricate cadmium sulfide (CdS) nanoparticles using watermelon rind (WR), banana peel (BP) extracts, and nickel ferrite (NiFe₂O₄) nanoparticles using star anise (SA) extract. The synthesized nanoparticles were characterized through scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential measurements, X-ray diffraction (XRD), and UV–Vis spectroscopy to investigate their structural, morphological, and optical properties. The integration of CdS with NiFe₂O₄ aimed to overcome limitations such as charge carrier recombination and photo corrosion, commonly encountered in conventional CdS-based photocatalysts. The core-shell structure demonstrated superior photocatalytic performance for hydrogen evolution. Photocatalytic hydrogen production analysis showed that NiFe₂O₄(300 °C)@BP-CdS achieved the most remarkable hydrogen evolution average rate of 1220.6 μmol g⁻¹ h⁻¹ after 5 h of irradiation, surpassing both the as-prepared and 600 °C calcined samples. The enhanced activity is ascribed to improved charge separation and elevated light absorption from the refined calcination procedure. Photoelectrochemical assessments, including chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS), also validated the enhanced photocurrent response and reduced charge transfer resistance of the NiFe₂O₄/CdS nanocomposite compared to its bare CdS. These findings underscore the potential of green-synthesized NiFe₂O₄@CdS nanocatalysts in advancing sustainable hydrogen production technologies. The findings contribute to both environmental preservation and economic sustainability.