多相流染料废水的臭氧高级氧化脱色行为研究

Decolorization of Textile Dyeing Wastewater by Ozonation in Multi-phase Flow Condition

以亚甲基蓝(MB)模拟染料废水,研究了多相流中染料的臭氧氧化脱色动力学,考察了活性炭、缓冲条件下的pH值以及羟基自由基(.OH)捕获剂对染料脱色行为的影响。试验结果表明,染料MB的臭氧氧化脱色过程符合伪一级动力学。活性炭的相界面催化作用能够促进染料的脱色,当颗粒状活性炭(GAC)浓度由3 g/L增大至15 g/L时,脱色速率呈现增大的趋势,且粉末状活性炭(PAC)催化脱色能力更强。缓冲条件下的pH增大,脱色速率明显加快,而且添加活性炭(>9 g/L)比自由基较活跃(pH=12.7)时的脱色速率常数k提高了一倍。强碱性(pH=12.7)缓冲条件下加入足够量(0.003 mol/L)羟基自由基捕获剂,结果表明HCO3-捕获自由基的能力强于叔丁醇,但由于捕获剂对自由基反应路径的控制作用依然有限,导致染料的脱色速率仍比酸性(pH=2.5)条件下快。

A bench scale experiment was conducted in purpose to investigate decolorization of dyeing wastewater by ozonation in the condition of multi-phase flow,for which a solution of MB（Methylene Blue） prepared as simulated dyeing wastewater was treated through the advanced oxidation process including adsorption of activated carbon and ozonation.The influences of activated carbon,buffered pH and the hydroxyl radical scavenger on decoloriztion were studied and the results indicated that MB decolorization fit the pseudo-first-order kinetic equation;that catalytic action existed in the phase-interface could promote the decolorization;and that decolorizing rate increased with the rise of buffered pH value and the addition of sufficient hydroxyl radical scavenger（0.003 mol/L） into a strong alkaline buffer system（pH=12.7） presented the fact indicating the advantage of HCO3-over t-butanol in terms of capturing of hydroxyl radicals and furthermore,decolorization rate in this condition was still higher than that in acidic condition of pH 2.5 because of the limited capacity of the radical scavenger in controlling the path of hydroxyl radicals.