Hoang Nguyen Tien, Nguyen Vo Thang, Minh Tuan Nguyen Dinh, Manh Tran Duc, Le Phuoc-Cuong, Van Tac Dinh, Mwazighe Fredrick M
The University of Danang, University of Science and Education, Da Nang, 550 000, Viet Nam.
The University of Danang, University of Science and Education, Da Nang, 550 000, Viet Nam.
Chemosphere. 2022 Jul;298:134197. doi: 10.1016/j.chemosphere.2022.134197. Epub 2022 Mar 8.
This study investigated the degradation of methylene blue (MeB), methyl orange (MeO), and rhodamin B (RhB) by the UV/Persulfate (UV/PS) process. The dye degradation in the investigated UV-based Advanced Oxidation Processes (UV/AOPs) followed the first-order kinetic model. The second-order rate constant of the dyes with •OH, SO, and CO were calculated and found to be: k = 5.6 × 10 M s, [Formula: see text] = 3.3 × 10 M s, [Formula: see text] = 6.9 × 10 M s; k = 3.2 × 10 M s, [Formula: see text] = 13 × 10 M s, [Formula: see text] = 4.4 × 10 M s; k = 14.8 × 10 M s, [Formula: see text] = 5 × 10 M s, [Formula: see text] = 1 × 10 M s. The steady-state concentrations of •OH and SO (including other reactive species) were determined using both chemical probes and modeling methods (Kintecus® V6.8). In the UV/PS, the dye degradation depends on the pH of the solution with the order: k (at pH of 7) > k (in acidic conditions) > k (in alkaline conditions). The presence of water matrices had different impacts on dye degradation: 1) The HCO and Cl promoted the degradation efficiency of one dye, but also inhibited the degradation of other dyes; 2) Humic acid (HA) inhibited dye degradation as it scavenged both •OH and SO. The degradation of the dyes by UV/PS was also compared with the UV/Chlorine (UV/HOCl) and UV/HO and it was established that: 1) In UV/PS and UV/HOCl, SO and RCS contributed to dye degradation more than •OH, while •OH played a major role in dye degradation by UV/HO; 2) The calculated toxicity in UV/PS was the lowest probably due to the low toxicity of by-products; 3) For MeO and RhB, the UV/PS process is more beneficial for the total organic carbon (TOC) removal compared to that of the UV/HOCl and UV/HO processes; 4) The UV/PS showed lower cost than the UV/HOCl and UV/HO systems for MeO, and RhB degradation but higher cost for MeB removal.
本研究考察了紫外光/过硫酸盐（UV/PS）工艺对亚甲基蓝（MeB）、甲基橙（MeO）和罗丹明B（RhB）的降解情况。在所研究的基于紫外光的高级氧化工艺（UV/AOPs）中，染料降解遵循一级动力学模型。计算了染料与•OH、SO和CO的二级反应速率常数，结果如下：k = 5.6×10 M s，[公式：见原文] = 3.3×10 M s，[公式：见原文] = 6.9×10 M s；k = 3.2×10 M s，[公式：见原文] = 13×10 M s，[公式：见原文] = 4.4×10 M s；k = 14.8×10 M s，[公式：见原文] = 5×10 M s，[公式：见原文] = 1×10 M s。采用化学探针和建模方法（Kintecus® V6.8）测定了•OH和SO（包括其他活性物种）的稳态浓度。在UV/PS工艺中，染料降解取决于溶液的pH值，顺序为：k（pH = 7时）> k（酸性条件下）> k（碱性条件下）。水基质的存在对染料降解有不同影响：1）HCO和Cl促进了一种染料的降解效率，但也抑制了其他染料的降解；2）腐殖酸（HA）由于清除了•OH和SO而抑制了染料降解。还将UV/PS工艺对染料的降解与UV/氯（UV/HOCl）和UV/HO工艺进行了比较，结果表明：1）在UV/PS和UV/HOCl工艺中，SO和RCS对染料降解的贡献大于•OH，而•OH在UV/HO工艺对染料的降解中起主要作用；2）UV/PS工艺中计算出的毒性最低，可能是由于副产物毒性较低；3）对于MeO和RhB，与UV/HOCl和UV/HO工艺相比，UV/PS工艺对总有机碳（TOC）的去除更有利；4）对于MeO和RhB的降解，UV/PS工艺的成本低于UV/HOCl和UV/HO系统，但对于MeB的去除成本更高。
