State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, People's Republic of China.
Environ Sci Pollut Res Int. 2012 Feb;19(2):577-84. doi: 10.1007/s11356-011-0591-4. Epub 2011 Aug 27.
The oxone process for azo dye decolorization has drawbacks such as difficulties with reuse, risks of secondary pollution, and high costs associated with UV irradiation. This study aims to explore the use of oxone for decolorization in the absence of catalyst and under natural sunlight conditions (i.e., oxone/natural sunlight system) and evaluate the impacts of operating parameters (reagent dosage, initial methyl orange (MO) concentration, and initial pH) and coexisting substances (humic acid, NO(3)(-), metal ions) on the system's decolorization efficiency.
Four levels of operating parameters were configured under a Taguchi L(16) orthogonal array design to examine their effects on decolorization efficiency. Fractional factional design was then used to derive the optimal combination of operating parameters, under which the effects of coexisting substances at various concentrations were examined. In addition, H(2)O(2), CH(3)OH, and (CH(3))(3)COH were used to derive the possible reaction mechanisms in the oxone/sunlight system, while ultrasonic power was used to shorten the reaction time.
In the oxone/sunlight system, (1) the MO decolorization efficiency reaches 96.4% under the optimal operating conditions: initial concentration, 100 mg L(-1); initial pH 6.04; dosage of reagent, 3 mmol L(-1); and reaction time, 30 min. (2) Coexisting substances do not affect the overall decolorization efficiency. (3) The decolorization of MO in the oxone/sunlight system takes place mainly via oxidation by SO(4)·⁻. (4) Ultrasonic irradiation could remarkably accelerate the MO decolorization process.
Effective for MO decolorization, the oxone/sunlight system improves over the traditional oxone process with advantages of lower costs and avoiding secondary pollution by catalyst.
过一硫酸盐（Oxone）氧化法用于偶氮染料的脱色存在一些缺点，例如催化剂难以重复使用、存在二次污染风险以及与紫外线辐照相关的高成本。本研究旨在探索在无催化剂且在自然光条件下（即过一硫酸盐/自然光体系）使用过一硫酸盐进行脱色，并评估操作参数（试剂用量、初始甲基橙（MO）浓度和初始 pH 值）和共存物质（腐殖酸、NO₃⁻、金属离子）对体系脱色效率的影响。
在 Taguchi L（16）正交数组设计下配置了四个操作参数水平，以研究它们对脱色效率的影响。然后使用部分因子设计得出最佳操作参数组合，在此条件下研究了不同浓度共存物质的影响。此外，还使用 H₂O₂、CH₃OH 和（CH₃）₃COH 推导出过一硫酸盐/日光体系中的可能反应机制，同时使用超声波功率缩短反应时间。
在过一硫酸盐/日光体系中，（1）在最佳操作条件下（初始浓度 100 mg/L、初始 pH 值 6.04、试剂用量 3 mmol/L 和反应时间 30 min），MO 的脱色效率达到 96.4%。（2）共存物质不会影响整体脱色效率。（3）MO 在过一硫酸盐/日光体系中的脱色主要通过 SO₄·⁻的氧化作用进行。（4）超声辐射可以显著加速 MO 的脱色过程。
过一硫酸盐/日光体系对 MO 具有有效的脱色效果，与传统的过一硫酸盐工艺相比，该体系具有成本更低和避免催化剂二次污染的优点。
