(Press-News.org) Researchers have developed an environmentally friendly way to transform discarded orange peels into a highly efficient material that can remove toxic dyes from wastewater, offering a sustainable solution to two growing global challenges: agricultural waste management and water pollution.
Industrial dye pollution is a major environmental problem worldwide. Each year, more than 700,000 tons of synthetic dyes are produced, and a significant portion enters waterways due to incomplete treatment. Even at low concentrations, dyes can discolor water, block sunlight essential for aquatic life, and produce harmful compounds that pose risks to human and ecosystem health. Adsorption using carbon-based materials has emerged as a promising cleanup strategy, but many existing materials face limitations in performance, cost, and sustainability.
In a new study, scientists created an advanced biochar adsorbent using orange peel waste, a byproduct generated in large quantities during citrus processing. The research introduces a dual-activation method using zinc chloride and iron chloride to engineer a hierarchically porous biochar with enhanced surface reactivity.
“This work shows how agricultural waste can be transformed into high-value materials for environmental protection,” said corresponding author Lei Zhang. “By combining two activation strategies, we created a biochar that not only has a large surface area but also contains multiple active sites that work together to capture pollutants efficiently.”
The new material, known as Fe/Zn-OPBC500, demonstrated exceptional performance in removing methylene blue, a commonly used industrial dye that often contaminates textile wastewater. Laboratory tests showed the material achieved an adsorption capacity of 237.53 milligrams of dye per gram of biochar and removed nearly 97 percent of the dye within one hour. The material also maintained strong performance across a wide range of water conditions and retained significant removal capacity even after seven reuse cycles.
The material’s performance is driven by its unique structure. The dual chemical activation process creates a network of pores ranging from microscopic to nanometer scale, dramatically increasing the available surface area for pollutant capture. At the same time, iron-based active sites and oxygen-containing functional groups provide multiple mechanisms for binding dye molecules, including electrostatic attraction, chemical bonding, hydrogen bonding, and interactions between aromatic carbon structures and dye molecules.
“Traditional biochar often suffers from limited adsorption capacity or poor recyclability,” Zhang explained. “Our synergistic modification strategy solves these challenges by integrating structural engineering with surface chemistry design, resulting in both high efficiency and durability.”
The research also highlights the environmental benefits of valorizing citrus processing waste. Orange peels account for approximately 40 to 50 percent of total fruit mass during processing, and they are often discarded through landfilling or burning, which can contribute to secondary pollution. Converting this waste into advanced adsorbents provides a sustainable alternative that supports circular economy principles while reducing environmental impact.
Beyond dye removal, the researchers believe the material could be adapted for treating other types of industrial contaminants. The study provides new insights into how engineered biochar structures can be tailored to target specific pollutants, potentially expanding applications in wastewater treatment, environmental remediation, and resource recovery.
“Our findings provide a roadmap for designing next-generation carbon materials from renewable biomass,” Zhang said. “With further scaling and optimization, this approach could contribute to cleaner water systems while reducing agricultural waste.”
The research demonstrates how innovative material science can transform common food waste into powerful environmental technologies, helping address pollution challenges while promoting sustainable resource utilization.
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Journal reference: Zhang L, Liu X, Liu W, Du H, Guo J. 2026. Hierarchical porous biochar with Fe/Zn co-activation derived from orange waste: enhanced methylene blue adsorption and mechanistic insights. Biochar X 2: e004 doi: 10.48130/bchax-0026-0001
https://www.maxapress.com/article/doi/10.48130/bchax-0026-0001
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About the Journal:
Biochar X (e-ISSN: 3070-1686) is an open access, online-only journal aims to transcend traditional disciplinary boundaries by providing a multidisciplinary platform for the exchange of cutting-edge research in both fundamental and applied aspects of biochar. The journal is dedicated to supporting the global biochar research community by offering an innovative, efficient, and professional outlet for sharing new findings and perspectives. Its core focus lies in the discovery of novel insights and the development of emerging applications in the rapidly growing field of biochar science.
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Turning orange waste into powerful water-cleaning material
2026-02-06
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