In the present study, a photodegradation technique was employed for the removal of methylene blue dye from aqueous solution using a tungsten oxide-based photocatalyst. The photocatalyst was synthesized via a green synthesis route utilizing a plant extract (PE) under acidic conditions. The synthesized photocatalyst was characterized by various spectroscopic and microscopic techniques that confirmed the presence of various functional groups on the catalyst surface and revealed a narrow bandgap of ~3.0 eV. The synthesized particles exhibited a nanoscale dimension ranging from 10 to 15 nm. The photocatalytic activity of the material was evaluated under ultraviolet light, visible light, and sunlight irradiation, demonstrating the efficient degradation of methylene blue under all light sources. Furthermore, catalysis reusability studies indicated excellent stability, with consistent photocatalytic performance observed after five successive cycles.

This study reports the preparation of a novel hybrid composite and its application in adsorption. For this composite preparation, zirconia (ZrO₂) was precipitated onto an integrated framework of reduced graphene oxide (rGO) and black cumin (BC) seeds. Characterization using Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, and transmission electron microscopy confirmed the successful incorporation of ZrO₂ nanoparticles (5–20 nm) into the integrated carbon framework of rGO and seed powder. The microscopic analysis further revealed that the ZrO₂ NPs were dispersed throughout the integrated rGO-BC framework. Using the rGO-BC@ZrO₂ composite, methylene blue dye was decontaminated from water through a batch adsorption process. The rGO-BC@ZrO₂ composite achieved 96% MB adsorption at an adsorbent dose of 2.0 g/L, and nearly 100% when the adsorbent concentration was 3.0 g/L. Modeling of the experimental adsorption values was also established to verify the adsorption viability and mechanism. Thermodynamic modeling confirmed the feasibility and spontaneity of the present batch adsorption process. Isotherm modeling, which showed its compatibility with the Freundlich isotherm, suggested multilayer adsorption. rGO-BC@ZrO₂ demonstrated good persistence and reusability for methylene blue for up to five consecutive adsorption cycles. Thus, this study presents optimistic results regarding water purification.

This study demonstrated the synthesis of Fe₂MnO₄ modified by citric acid, a biodegradable acid, using a simple co-precipitation method. Characterization was performed using qualitative analysis techniques such as Fourier-transformed infrared spectroscopy, scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, X-ray diffraction, selected-area electron diffraction, N₂ adsorption–desorption, and zero-point charge. The prepared nanoparticles had a rough and porous surface, and contained oxygenous (-OH, -COOH, etc.) functional groups. The specific surface area and average pore size distribution were 83 m²/g and 5.17 nm, respectively. Net zero charge on the surface of the prepared nanoparticles was observed at pH 7.5. The prepared nanoparticles were used as an adsorbent to remove methylene blue dye from water under various conditions. Using small amounts of the adsorbent (2.0 g/L), even a high concentration of MB dye (60 mg/L) could be reduced by about ~58%. Exothermic, spontaneous, feasible, and monolayer adsorption was identified based on thermodynamics and isotherm analysis. Reusability testing verified the stability of the adsorbent and found that the reused adsorbent performed well for up to three thermal cycles. Comparative analysis revealed that the modified adsorbent outperformed previously reported adsorbents and unmodified Fe₂MnO₄ in terms of its partition coefficient and equilibrium adsorption capacity under different experimental conditions.

Oriental Journal of Chemistry is a peer reviewed quarterly research journal of pure and applied chemistry. It publishes standard research papers in almost all thrust areas of current chemistry of academic and commercial importance. It provides a platform for rapid publication of quality research papers, reviews and chemistry letters. Oriental Journal of Chemistry is abstracted and indexed in almost all reputed National and International agencies.