Water contamination remains a critical global challenge because synthetic dyes from industrial activities pose a severe threat to both aquatic ecosystems and human health. In a study recently published in the journal Scientific Reports, Fariha Aman and a team of international researchers investigated a sustainable solution using Cladophora glomerata, a type of freshwater macroalgae. The researchers converted this algae into 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 through a process called slow 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, where the 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 heated at 350 degrees Celsius in the absence of oxygen. This transformation creates a carbon-rich material with a porous structure and various chemical groups on its surface that are highly effective at trapping pollutants. The primary target of the study was Eriochrome Black T, a common anionic azo dye that is notoriously difficult to break down using standard biological treatments and is known for its toxic and potentially cancer-causing effects.

The findings reveal that the algal-derived biochar is an exceptionally efficient adsorbent for wastewater remediation. Under optimized experimental conditions, the biochar demonstrated a removal efficiency of 95.31 percent. The researchers found that the process worked best at a low 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 2, where the surface of the biochar becomes positively charged. This charge creates a strong electrostatic attraction to the negatively charged dye molecules, pulling them out of the water and onto the solid surface of the adsorbent. The study determined that the maximum amount of dye the material could hold was approximately 58.56 milligrams per gram of biochar. This performance is competitive with many other low-cost materials currently being tested, such as waste from sweet potatoes or coffee grounds, making it a viable candidate for large-scale environmental applications.

Beyond its impressive cleaning stats, the production of this biochar aligns with the principles of a circular economy. Cladophora glomerata is often considered an environmental nuisance when it overgrows in rivers, but this research turns that problematic waste into a high-value tool for sanitation. The physical analysis of the biochar showed it is rich in essential minerals like calcium, potassium, and magnesium, and it possesses a complex surface chemistry that allows it to bond with hazardous chemicals through several different mechanisms. Because the algae is abundant and the conversion process is relatively straightforward, this method provides an affordable alternative for regions heavily impacted by textile industry wastewater that may lack the infrastructure for expensive conventional treatment plants.

The study also delved into the mathematical and thermal behavior of the adsorption process to ensure its reliability. The researchers confirmed that the interaction between the dye and the biochar is a spontaneous and endothermic process, meaning it occurs naturally and performs even better as temperatures rise slightly. They also identified that the rate-limiting step of the cleaning process is chemisorption, where the dye molecules form actual chemical bonds with the functional groups on the biochar surface. This ensures that the pollutants are tightly held and not easily released back into the environment. By meeting international goals for clean water and sanitation, this research highlights how underutilized natural resources can be harnessed to protect public health and restore the integrity of our water systems.

Source: Aman, F., Farooq, U., Bibi, K., Hasan, M. A., Ali, S., Badshah, S. L., Ahmad, S., Muhammad, N., Sultana, S., Ilyas, M., Silva Acioly, T. M., & Ydyrys, A. (2026). Sustainable adsorptive removal of eriochrome black T dye using Cladophora glomerata biochar. Scientific Reports.