Water pollution with organoarsenics poses a significant threat to environmental health, particularly due to the inefficient oxidative degradation of these compounds and the challenge in immobilizing the resultant inorganic arsenic. Recent research introduces a groundbreaking solution to this dilemma: the biochar accelerated Fenton (BA-Fenton) process, which shows exceptional efficiency in removing roxarsone (ROX) and inorganic arsenic from contaminated water.

The BA-Fenton process leverages the catalytic capabilities of biochar, a sustainable 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 pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More, to significantly enhance the degradation and immobilization mechanisms traditionally hindered in water treatment. This innovative approach not only accelerates the redox cycle of Fe2+/Fe3+, facilitating the generation of hydroxyl radicals for effective organoarsenic degradation, but also stabilizes arsenic-iron sludge through mechanisms like hydrogen bonding, electrostatic attraction, and surface complexation.

In comparison to the conventional Fe2+/H2O2 process, adding biochar to the Fenton reaction boosts the degradation efficiency of ROX from 48.2% to an impressive 98.2% and the total arsenic elimination rate from 67.6% to 97.3%. Such enhancements are attributed to the increased production of reactive oxygen species, notably hydroxyl radicals, whose concentration in the BA-Fenton process is three times higher than that in the classic Fenton reaction.

Moreover, this process significantly mitigates the secondary leachingLeaching is the process where nutrients are dissolved and carried away from the soil by water. This can lead to nutrient depletion and environmental pollution. Biochar can help reduce leaching by improving nutrient retention in the soil.   More of arsenic, reducing its concentration in the treated water to as low as 13.9 µg/L, well below the environmental quality standard for surface water in China. The dual functionality of biochar not only promotes the oxidative transformation of ROX to As(V) but also ensures the immobilization of the inorganic arsenic, addressing the primary challenges in organoarsenic remediation.

This study presents a promising “Two Birds with One Stone” strategy that employs biochar to tackle the complex issue of organoarsenic pollution. The BA-Fenton process, with its low cost, environmental friendliness, and sustainability, offers a viable and effective solution for the ultimate disposal of industrial wastewater containing organoarsenics, extending its applicability to tap water, lake water, and chicken manure leachate.