Rapid and continuous oxidation of organic contaminants with ascorbic acid and a modified ferric/persulfate system

• A novel Fe3+/H2A/PS system was proposed to oxidize organic pollutants.
• Ascorbic acid could enhance the efficiency of iron activated persulfate process.
• The pollutants could be removed quickly and continuously.
• The system is efficient in a wide pH0 range (2.0–6.2).
• The reduction and chelating ability of H2A are responsible for the good performance.

An eco-friendly reagent, Vitamin C (ascorbic acid, H2A), has been introduced into a traditional iron activated persulfate (PS) process (Fe2+/PS). The modified Fe3+/H2A/PS system exhibits a rapid and continuous oxidation of organic contaminants, and shows great advantages over the conventional Fe2+/PS process by enhanced removal efficiency and wide working initial pH (pH0 2.0–6.2). This can be attributed to both the reduction and chelating ability of ascorbic acid. The optimal dosages of ascorbic acid, ferric ion and persulfate were determined by batch experiments. Radical quenching experiments show that SO4− and HO are the main reactive species in the Fe3+/H2A/PS process. Based on these results, a plausible degradation mechanism is proposed. The modified system may provide a simple and effective technology for the decomposition of refractory organics in water.

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