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Orange Peel Biochar Helps Clean Textile Wastewater
Scientists have found a new way to clean polluted textile wastewater using discarded orange peels. The method turns fruit waste into a powerful material that removes harmful industrial dyes from water.
When the black powder made from orange peels enters dye polluted water, the result is clear. Within one hour, the dark blue water becomes almost transparent. The biochar traps the dye molecules inside its porous structure.
One Waste Solves Another Environmental Problem
The study was conducted by Lei Zhang and researchers at Shaanxi University of Science and Technology in China. They developed a special biochar from orange peel waste to address dye pollution from textile factories.
The textile industry produces over 700,000 tons of synthetic dyes each year. About 10 percent of these dyes reach rivers and streams. Even small amounts can discolor water and block sunlight. Some dyes also break down into toxic compounds that harm human health.
European rules now limit dye levels in wastewater to 0.05 milligrams per litre. Many treatment plants struggle to reach this standard.
Why Orange Peels Are a Smart Choice
China produces more than 45 million tons of citrus fruits each year. Processing plants discard almost half of each fruit, mainly the peel. Most of this waste ends up burned or dumped.
Orange peels contain natural fibers and oxygen rich compounds. These features make them ideal for producing activated carbon. Instead of becoming waste, the peels gain new value in water treatment.
How the Biochar Was Made
The team treated orange peel powder with zinc chloride and iron chloride. They then heated it to 500 degrees Celsius without oxygen. This process created many tiny pores inside the carbon.
Zinc chloride formed a porous network, while iron particles created active binding sites. The final material is called Fe Zn OPBC500. It has a much larger surface area than untreated biochar.
Strong Results in Dye Removal Tests
The researchers tested the biochar using methylene blue, a common textile dye. One gram of biochar absorbed up to 237.53 milligrams of dye. The material removed about 97 percent of the dye within one hour.
The biochar worked well across different pH levels. It also performed strongly in salty water, which often reduces treatment efficiency. After seven reuse cycles, it still retained high dye removal capacity.
Why This Biochar Works So Well
The material combines structure and chemistry. Its pores range from large channels to tiny cavities. This design increases surface area more than sixteen times.
Iron based sites attract dye molecules through several interactions. These include electrostatic attraction, chemical bonding, and hydrogen bonding. This balance improves both efficiency and durability.
Selective and Reusable Performance
Common ions like sodium had little effect on performance. Calcium and iron ions reduced efficiency because they competed for binding sites. After multiple cleaning cycles, the biochar still removed over 113 milligrams of dye per gram.
A Sustainable Future for Water Treatment
The study shows how agricultural waste can support cleaner water systems. Orange peel biochar offers a low cost and eco friendly option for treating industrial wastewater.
Researchers believe similar materials could remove other industrial pollutants. This approach could reduce waste while improving environmental protection.
Study Source
Research published in a peer reviewed journal and available through MaxApress scientific publications.
