ABSTRACT

The impact of various mineral anions, diverse organic substrates and different environmental matrices on the removal of C.I. reactive green 12 (RG12), a refractory textile dye, by UV/chlorine emerging advanced oxidation process (AOP) was performed. The co-exposure of RG12 (20 mg L⁻¹) to UV and chlorine (0.5 mM) at pH 5 produced a strong synergism on the degradation rate. Radical probe technique showed that ^●OH and Cl₂^●− were the main source of the synergistic effect. Bromide, bicarbonate and chloride at small dosage, i.e. 1 mM, enhanced the rate of RG12 degradation, but higher concentrations of these anions quenched the degradation process. Sulphate anions did not alter the degradation rate of the dye, but nitrite quenched it at ∼ 90%. The inhibiting effect of nitrate appeared only at advanced reaction time (>1 min).On the other hand, natural organic matter (NOM) reduced effectively the degradation rate. Besides, SDS surfactant at only 1 µM accelerated the degradation efficiency by ∼12%. However, Tween 80 has shown an insignificant effect, whereas reductions of 10% and 30% were recorded by Triton X100 and Tween 20, respectively. The RG12-degradation rate was not affected in the mineral water, but it was drastically improved in seawater. Conversely, a huge drop in the RG12-degradation efficiency was obtained in the wastewater effluent. UV/chlorine process is highly viable for degrading pollutant in matrices free of NOM. However, the process losses its potential application in matrices riche of NOM.

摘要

进行了各种矿物阴离子、各种有机底物和不同环境基质对通过紫外/氯新兴高级氧化工艺 (AOP) 去除难熔纺织染料 CI 活性绿 12 (RG12) 的影响。^{RG12 (20 mg L -1} ) 在 pH 5下共同暴露于 UV 和氯 (0.5 mM) 对降解速率产生了强烈的协同作用。自由基探针技术表明^● OH 和 Cl ₂ ^●−是协同效应的主要来源。溴化物、碳酸氢盐和氯化物的小剂量（即 1 mM）提高了 RG12 的降解速率，但这些阴离子的较高浓度会淬灭降解过程。硫酸根阴离子不会改变染料的降解率，但亚硝酸根可将其淬灭至 90% 左右。硝酸盐的抑制作用仅在反应时间提前(>1 min)时出现。另一方面，天然有机物(NOM)有效地降低了降解速率。此外，仅 1 µM 的 SDS 表面活性剂将降解效率提高了 ~12%。然而，Tween 80 显示出微不足道的效果，而 Triton X100 和 Tween 20 分别记录了 10% 和 30% 的减少。RG12-降解率在矿泉水中不受影响，但在海水中显着提高。反过来，废水中的 RG12 降解效率大幅下降。UV/氯工艺对于降解不含 NOM 的基质中的污染物非常可行。然而，该过程失去了在富含 NOM 的矩阵中的潜在应用。