Ganga Ram Chaudhary

The widespread accumulation of microplastics in aquatic and terrestrial ecosystems has emerged as a critical global environmental challenge, posing serious risks to ecological and human health. The persistence of polyethylene (PE) microplastics in aquatic environments poses a significant environmental challenge due to their chemical stability and resistance to natural degradation. Herein, we report a visible-light-active Co−CeO2/g-C3N4 composite for the efficient photocatalytic degradation of PE microplastics. Structural and spectroscopic characterization confirmed successful formation of the Co−CeO2/g-C3N4 composite, with preserved crystalline phases, strong interfacial interactions, uniform dispersion of Co−CeO2 nanoparticles over g-C3N4, homogeneous elemental distribution, and enhanced visible-light absorption and interfacial charge-transfer behaviour. Under visible-light irradiation, the composite achieved 59.76 ± 0.8% PE mass loss within 24 h, substantially outperforming the individual components. Oxidative degradation was further supported by an increase in the carbonyl index from 0.05 to 1.38, together with pronounced surface erosion, fragmentation, and increased roughness. EPR and radical-scavenging experiments identified •OH and O2•− as the major reactive species, with •OH playing the predominant role. LC−MS and TOC analyses confirmed the formation and subsequent transformation of soluble PE-derived intermediates. MTT-based cytotoxicity assessment using HepG2 and MCF-7 cells further showed that the degradation-product-containing aqueous phase did not exhibit greater cytotoxicity than pristine PE under the tested conditions. These findings demonstrate the potential of Co−CeO2/g-C3N4 for visible-light-driven PE microplastic degradation and highlight the potential of advanced heterostructured photocatalysts for environmental remediation.

Antibiotic residues are emerging pollutants that severely threaten both environmental safety and human health, demanding advanced catalytic solutions. This study reports a Z-scheme Ni–BiOCl@ZIF-67 (NBZ) heterostructure synthesized via a solvothermal route. By coupling nickel-doped BiOCl with a ZIF-67 metal–organic framework (MOF), the composite effectively addresses the inherent limitations of individual components, such as wide band gaps and rapid charge carrier recombination. The synergistic interaction between the conductive MOF and the doped semiconductor facilitates rapid electron transfer and shows a high sensitivity (0.0183 μA nM–1), an ultralow detection limit (0.90 nM), and an extensive linear dynamic range (10–100 nM), highlighting its strong potential for trace-level detection. Moreover, the incorporation of Ni2+ ions into the BiOCl lattice improves visible-light absorption and facilitates charge separation, while coupling with ZIF-67 enables efficient spatial separation of charge carriers via a direct Z-scheme mechanism. This tailored heterostructure not only extends the visible-light absorption range but also enhances photocatalytic efficiency for the degradation of ciprofloxacin (CIP) (90.05%) under solar-simulated conditions. These findings highlight the potential of the NBZ catalyst as a highly efficient, rapid, and environmentally sustainable platform for wastewater purification, particularly in addressing pollutants from textile and pharmaceutical industries.

There has been an increase in plastic production and consumption in recent years, which has become a major global environmental challenge due to the persistence of plastics in nature. Microplastics (MPs) contamination signifies a serious environmental challenge, yet discrepancies among analytical methodologies and sample matrices continue to limit the harmonization and cross-comparability of reported data. This study investigates MPs’ extractions from the soil collected from the Sukhna Lake Watershed, Chandigarh, India. This research employs systematic sampling for soil collection by dividing a single sampling site into a 4 × 4 grid. Furthermore, the density separation method was employed for the extraction of MPs from the soil samples. The extracted MPs were comprehensively characterized using a fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray Spectroscopy (EDS)-mapping, X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma mass spectrometry (ICP-MS), which was used to elucidate the molecular structure, morphology, surface chemistry, and elemental composition of the MPs. The MPs were further solubilized in various solvents and analyzed using UV-visible spectroscopy. The results from the FTIR and FE-SEM demonstrated the presence of various types of plastics at the collecting site, including polyethylene, polypropylene, polyvinyl chloride, and polyethylene terephthalate in different morphologies. These techniques also confirmed that plastics had undergone prolonged interactions with the environment, enabling them to interact with contaminants. Furthermore, the results from XPS, ICP-MS and UV-Visible spectroscopy suggested the presence of organic and inorganic contaminants, including heavy metals, in the MPs. The combined results emphasize that the MPs present in the watershed can function as potential vectors for the accumulation and transport of potent and persistent contaminants. This research delivers new insights into MPs as environmentally aged, oxidized materials with mineral-organic surface coatings, highlighting their enhanced capacity to act as carriers of pollutants and their broader environmental implications.

The widespread use of thiamethoxam, a neonicotinoid pesticide, poses increasing risks to environmental and food safety, highlighting the urgent need for rapid, selective, and biomass-derived analytical platforms. In this study, fluorescent carbon dots (CDs) were synthesized from rice straw via a water-based hydrothermal approach and subsequently functionalized with a biopolymer-based molecularly imprinted polymer (MIP) for the selective detection of thiamethoxam. The synthesized CDs exhibited strong blue fluorescence with a maximum emission wavelength at 455 nm. Integration of the CDs with a thin MIP layer generated specific binding cavities complementary to thiamethoxam, significantly enhancing selectivity toward the target analyte over structurally related neonicotinoids. The resulting CD@MIP sensor demonstrated rapid and concentration-dependent fluorescence quenching, with a wide linear detection range from 1 to 500 nM and a limit of detection of 9.15 nM. An imprinting factor of 3.54 confirmed the selective recognition capability of the imprinted system. The developed sensing platform was successfully validated using real environmental water samples, achieving recovery values between 100% and 102% with relative standard deviations ranging from 0.9% to 2.5%, thereby demonstrating good accuracy and reproducibility. Overall, this work presents a biomass-derived and efficient fluorescent sensing platform for monitoring pesticide residues, with promising applications in environmental monitoring and food safety analysis.

Sustainable management of potentially hazardous industrial waste persists as a major remediation challenge across the globe. Herein, we have demonstrated a sustainable design strategy that not only provides a remediation of industrial waste but also utilizes the same in a multifunctional manner as a strategic component of several energy and remediation-related assemblies. Precisely, waste sludge of electrochemical industries was collected and appropriately conditioned to induce lattice defects and oxygen vacancies. The conditioned sludge was adequately characterized and was revealed to possess highly enriched metallic content. Both the oxygen vacancies and the high metallic/metal oxide content enhanced the textural and electronic attributes of the sludge-derived materials, which was validated using different applications. For the energy generation aspect, the sludge material was applied to develop a hydroelectric cell, which exhibited an excellent power of 13.6 W/m2 with an open circuit voltage of 0.9 V. Besides, the conditioned sludge was applied as a supercapacitor and displayed excellent performance with a maximum capacitance of 338 F/g, and a maximum energy density of 53 Wh/kg was observed with 91% capacitance retention up to 2000 cycles. Furthermore, the defect-engineered sludge was also tested as a photocatalytic material and performed excellently for treating a model water contaminant, methylene blue (MB), under sunlight exposure. With these outcomes, this study shows that not only industrial waste materials can be sustainably treated but they can also be strategically harnessed to develop multifunctional conjugates to tackle several critical challenges persisting in the energy and remediation related sectors.

Morphological and electronic features of the photocatalysts are established together during the nucleation phase and are central to their activities. Solvent-based approaches can be effective in comodulating these properties, owing to their direct influence on the nucleation dynamics of the photocatalysts. Building on this realization, the present study demonstrates how a simple change in the reaction medium of a model photocatalyst, Bi2WO6, can remarkably transform both its morphological and electronic features. The nucleation dynamics of Bi2WO6 was analyzed using four solvent systems, i.e., water, ethylene glycol (EG), urea/choline chloride-based deep eutectic solvents (DES) (U:Ch), and urea/fructose-based natural deep eutectic solvents (NADES) (U:F). The extensive hydrogen-bond frameworks of Bi2WO6/U:Ch and Bi2WO6/U:F showed a remarkable influence on the morphology and electronic properties, likely via effects on nucleation and growth control. The effect of altered morphological and electronic features was validated using photocatalytic experiments against model pollutants, malachite green (MG) and tetracycline hydrochloride (TC), wherein Bi2WO6/U:Ch and Bi2WO6/U:F systems with enhanced morphological and electronic attributes exhibited a maximum degradation performance. The obtained results were rigorously validated using scavenging analysis, and a detailed mechanistic outlook was presented using precise electronic structure investigation. With these outcomes, this study shows that hydrogen-rich solvent systems such as DESs and NADESs are not merely a green replacement of the conventional solvents but can be effectively utilized as strategic tools to precisely engineer key structural features of the photocatalysts.