This comprehensive review examines hydrogen’s potential as a pivotal clean energy carrier, focusing on its role in replacing fossil fuels across various industries. This study also examines recent advancements in hydrogen production technologies, including electrolysis, steam methane reforming, and biomass gasification, emphasizing their economic and environmental impacts. Special attention is given to hydrogen produced from renewable sources like solar and wind energy, emphasizing its benefits in reducing carbon emissions and contributing to a sustainable energy future. The review discusses technological challenges, cost factors, and the necessary infrastructure for hydrogen production and storage, particularly in relation to achieving global energy transition goals. Furthermore, the study stresses the importance of government policies and international collaboration to drive the adoption of hydrogen technologies. The study concludes by outlining the transformative potential of hydrogen in decarbonizing key sectors such as transportation and heavy industry. It demonstrates the significant contribution of hydrogen to a low-carbon global energy system and provides valuable insights into its role in improving grid stability, energy security, and supporting sustainable industrial practices.

Global energy consumption has drastically increased over the years due to population growth and industrialization. This has prompted an exploration for clean and renewable energy alternatives. Microalgae are widely recognized as a promising third‐generation energy source because they have the capability to generate biofuels, including biochar. The utilization of microalgal biomass has been gaining traction because of their advantages, such as fast growth, a high rate of production, and high carbon‐fixing efficiency. Thermochemical methods like hydrothermal carbonization, torrefaction, and pyrolysis can be employed to harness energy from microalgae. The different thermochemical methods employed for converting microalgal biomass into biochar have been discussed, as well as the factors affecting these methods. In addition, a dedicated section covered the components and properties of the generated biochar, including its thermal and surface properties. Furthermore, the economic analysis of the production of biochar from microalgae as well as the applications of microalgae‐derived biochar were presented and discussed, along with suggestions for further research.

This study investigated the use of zinc oxide nanoparticles (ZnO NPs) as an adsorbent for removing total phenols from textile wastewater. The ZnO NPs were synthesized by reducing Zn(NO₃)₂⋅6H₂O using an extract from Neem leaves (Azadirachta indica). Characterization of the adsorbent was performed using Fourier Transform Infrared (FTIR) spectroscopy to identify functional group modifications, high-resolution scanning electron microscopy (HRSEM) for structural orientation, energy dispersive spectroscopy (EDS) for elemental analysis, and X-Ray diffraction analysis (XRD) for crystallinity, revealing particle crystallinity around 200 nm. Adsorption experiments were conducted over contact times of 20–60 min, with adsorbent loadings between 0.2 and 1 g/100 mL, and temperatures ranging from 30 to 50 °C. Optimal phenol removal, achieving 55.93% (0.67 mg/L), occurred at 43.40 min, 33.70 °C, and an adsorbent dosage of 0.69 g/L of textile wastewater. The phenol adsorption process using ZnO NPs was exothermic, spontaneous, and required low energy, fitting well with the Langmuir isotherm and following a pseudo-second-order kinetic model.