Catalytic transfer hydrogenation (CTH) provides a practical and sustainable approach for reducing unsaturated compounds, serving as an alternative to high-pressure H₂ in laboratory and fine chemical contexts. This broad reaction class includes asymmetric transfer hydrogenation (ATH), a key strategy in enantioselective synthesis due to its operational simplicity, high stereocontrol, and compatibility with sensitive functional groups. A central variable governing CTH efficiency is the role of bases, which may function as essential activators, co-hydrogen donors, or be entirely absent depending on the catalytic system. This review provides a comparison of base-assisted, base-free, and base-as-co-hydrogen-donor CTH methodologies across diverse metal catalysts and substrates. We highlight how bases such as triethylamine, K₂CO₃, and NaOH facilitate catalyst activation, modulate hydride formation, and tune reactivity and selectivity. The dual function of bases in formic-acid-driven systems is examined alongside synergistic effects observed with mixed-base additives. In contrast, base-free CTH platforms demonstrate how tailored ligand frameworks, metal-ligand cooperativity, and engineered surface basicity can eliminate the need for external additives while maintaining high activity. Through mechanistic analysis and cross-system comparison, this review identifies the key structural, electronic, and environmental factors that differentiate base-assisted from base-free pathways. Emerging trends—including greener hydrogen donors, advanced catalyst architectures, and additive-minimized protocols—are discussed to guide future development of sustainable CTH processes.

This research explores the dual role of biochar in addressing the escalating challenges of water salinity and pollution, focusing on its potential for both wastewater treatment and agricultural resilience. We investigated the adsorption capacity and efficiency of various biochar treatments to remove crystal violet dye from contaminated water. Biochar treated with H₂SO₄ demonstrated the highest adsorption capacity (450 mg/g). It consistently achieved 100% removal efficiency in all crystal violet concentrations tested, while silver-modified biochar showed a 99.95% removal rate at 50 ppm and an adsorption capacity of 5 mg/g. In agricultural applications, we evaluated the impact of biochar applications at concentrations of 1% and 3% on wheat crops irrigated with saline water of varying conductivity levels (0.63 and 10 dS/m). Wheat plants treated with 1% biochar exhibited the highest yield (26.6 cm) under 0.63 dS/m water conductivity, significantly outperforming the control group (17 cm). Biochar also resulted in elevated chlorophyll levels, with chlorophyll a ranging from 29.8 to 20.9 µg/mL and chlorophyll b ranging from 54 to 23 µg/mL, showing a marked improvement over the control. These findings demonstrate biochar’s potential to mitigate salinity-induced damage, with lower salinity conditions further enhancing chlorophyll a levels, while untreated plants showed reduced chlorophyll under high salinity.

Microplastics (MPs) have emerged as persistent environmental contaminants due to their persistence, widespread distribution, and potential risks to the environment and human health. This review focuses on the sources of MPs, their potential environmental risks, and human impacts, as documented in the recent literature from 2020 to 2026. Recent studies focusing on pathways, environmental weathering, and toxicity were evaluated and synthesized into the analysis. Previous studies have demonstrated that microplastics are transported across and between environmental compartments. Environmental degradation, driven by ultraviolet radiation, mechanical fragmentation, and oxidation, can alter microplastics’ surface characteristics, which may affect microplastic mobility, reactivity, and the solid-state adsorption of contaminants. Human exposure occurs primarily through ingestion and inhalation, with dermal and occupational exposure also contributing under certain conditions. Emerging evidence from in vitro, animal, and human tissue studies suggests that smaller particles, particularly nanoplastics, may contribute to oxidative stress, inflammation, and cellular injury; however, important uncertainties remain regarding environmentally realistic exposure levels, long-term health outcomes, and the extrapolation of experimental findings to real-world human health risk. Overall, the current literature highlights the need for standardized methodologies, improved integration of environmental monitoring and exposure assessment, and stronger evidence to support risk assessment and policy development.