In a pulp and paper mill, chlorine bleaching of pulp generates toxic aqueous stream containing various chlorophenols (CPs) which are not removed easily by biological process. The objective of the study was to optimize photo-catalytic oxidation reaction for synthetic wastewater containing mixture of mono-, di-, tri- and penta-CPs (i.e., 4-CP; 2,4-DCP; 2,4,6-TCP, and PCP) and evaluate its performance for simulated bleaching effluents produced during pulp bleaching stages. The experimental runs were performed in a glass reactor (capacity = 500 ml) with UV lamp (200-390 nm). A maximum TOC reduction of 93% was achieved for synthetic wastewater (initial TOC = 42 mg/L) at the following conditions: pH = 4.4 (unadjusted), H2O2 dose = 6.8 mM (stoichiometric), [H2O2]:[Fe2+] = 65 and run time = 37 min. Under these conditions, ∼90% of the chlorine atoms were dissolved as chloride ions in the treated wastewater. High performance liquid chromatography analysis on liquid samples extracted during the oxidation reaction revealed no accumulation of carboxylic acids in treated wastewater. At similar operating conditions, TOC removal from simulated bleaching effluent was 78% during photo-catalytic process compared to ∼50% obtained after Fenton's oxidation.

中文翻译：

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光催化氧化降解氯酚的性能：反应参数的优化和转化氧化产物的定量。

在制浆造纸厂中，纸浆的氯漂白会产生含有各种氯酚（CP）的有毒水流，而这些氯酚很难通过生物过程去除。这项研究的目的是优化含有单，双，三和五氯苯酚（即4-CP； 2，4-DCP； 2,4,6-）混合物的合成废水的光催化氧化反应。 TCP和PCP），并评估其在纸浆漂白阶段产生的模拟漂白废水的性能。实验运行在带有紫外线灯（200-390 nm）的玻璃反应器（容量= 500 ml）中进行。在以下条件下，合成废水（初始TOC = 42 mg / L）的最大TOC降低达到了93％：pH = 4.4（未调整），H2O2剂量= 6.8 mM（化学计量），[H2O2]：[Fe2 +] = 65，运行时间= 37分钟。在这种情况下 约有90％的氯原子以氯离子的形式溶解在处理后的废水中。对氧化反应过程中提取的液体样品进行的高效液相色谱分析表明，处理后的废水中没有羧酸的积累。在类似的操作条件下，光催化过程中模拟漂白废水中的总有机碳去除率为78％，而芬顿氧化后的总有机碳去除率为约50％。