A recent review by Hozefa Dhila and colleagues, published in Desalination and Water Treatment, highlights the potential of metal oxide/biochar nanocomposites (MOBNCs) for effectively removing toxic dyes from industrial wastewater. These materials combine the adsorption capabilities of biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More with the photocatalytic properties of metal oxides, addressing the limitations of traditional water treatment methods.

Biochar, a carbon-rich material derived from biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More, is eco-friendly and cost-effective but has limited adsorption capacity. Meanwhile, metal oxides like ZnO and TiO2 excel in photocatalysis but struggle with selective pollutant removal. MOBNCs merge these strengths by dispersing metal oxide nanoparticles on biochar, significantly enhancing their surface area and providing more active sites for adsorption and photocatalytic degradation.

The study demonstrates that MOBNCs can achieve up to 99% dye removal, such as methylene blue and reactive orange, under UV or visible light. Methods like sol-gel and hydrothermal synthesis ensure precise control of the composite structure, optimizing performance. Furthermore, MOBNCs are reusable and maintain efficiency over multiple cycles, making them a sustainable solution for industrial applications.

The paper also explores operational factors affecting performance, such as solution pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More and pollutant concentration, as well as the use of agricultural and municipal waste as biochar feedstocks. While challenges like scalability and cost remain, Dhila and colleagues emphasize the potential of MOBNCs as a transformative approach for water treatment.

Dhila, Bhapkar, & Bhame (2025) Metal oxide/biochar hybrid nanocomposites for adsorption and photocatalytic degradation of textile dye effluents: A review. Desalination and Water Treatment. https://doi.org/10.1016/j.dwt.2025.101004