A recent study in Biotechnology for Sustainable Materials by Smriti Yadav, Nikita Kundu, Ananya Bhattacharya, Palak Khinvasara, G. K. Aseri, and Neelam Jain investigates an eco-friendly approach for removing toxic hexavalent chromium from industrial tannery wastewater using rice hull biochar. The leather tanning industry is a major contributor to environmental pollution through the discharge of heavy metal effluents that pose severe risks to human health, aquatic ecosystems, and soil fertility. Conventional water treatment methods are frequently expensive and environmentally unsustainable, which creates an urgent need for low-cost biosorbents derived from agricultural residues. By converting abundant crop waste into a high-value carbon material, researchers aim to address industrial pollution while supporting circular economy principles and sustainable resource management.

The investigation focused on optimizing batch sorption parameters to maximize the removal of chromium from contaminated aqueous solutions. Experimental results revealed that rice hull biochar achieved a ninety-one percent chromium removal efficiency under optimal conditions, specifically at a 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 of four, a biosorbent dosage of zero point eight grams per liter, and a contact time of one hundred twenty minutes. Characterization analyses demonstrated that the biochar possesses a well-developed mixed microporous and mesoporous structure with a specific surface area of eighty-one point eight square meters per gram. The adsorption process followed pseudo-second-order kinetics and fit both Langmuir and Freundlich isotherm models, confirming that chemisorption, surface complexation, and electrostatic attraction govern the contaminant removal mechanism.

To evaluate practical applications beyond water purification, the researchers conducted seed germination and growth trials using chickpea plants. When treated effluent was combined with biochar residue at an optimized one-to-four dilution ratio consisting of twenty percent effluent and eighty percent biochar extract, the mixture successfully eliminated phytotoxicity. Seedlings irrigated with this balanced combination showed remarkable enhancements in root length, shoot length, leaf number, nodule formation, and overall fresh and dry biomass compared to control groups. These findings confirm that rice hull biochar not only remediates hazardous industrial effluents efficiently but also yields a nutrient-rich byproduct suitable for safe agricultural reuse in water-scarce regions.

Source: Yadav, S., Kundu, N., Bhattacharya, A., Khinvasara, P., Aseri, G. K., & Jain, N. (2026). A green approach for remediation of hexavalent chromium [Cr (VI)] from tannery effluent using rice hull biochar and assessing its impact on germination of Cicer arietinum (Chickpea). Biotechnology for Sustainable Materials, 3:8.