Factors affecting degradation of dimethyl sulfoxide (DMSO) by fluidized-bed Fenton process

Abstract

In this study, the target compound is dimethyl sulfoxide (DMSO), which is used as a photoresist stripping solvent in the semiconductor and thin-film transistor liquid crystal display (TFT-LCD) manufacturing processes. The effects of the operating parameters (pH, Fe(2+) and H2O2 concentrations) on the degradation of DMSO in the fluidized-bed Fenton process were examined. This study used the Box-Behnken design (BBD) to investigate the optimum conditions of DMSO degradation. The highest DMSO removal was 98 % for pH 3, when the H2O2 to Fe(2+) molar ratio was 12. At pH 2 and 4, the highest DMSO removal was 82 %, when the H2O2 to Fe(2+) molar ratio was 6.5. The correlation of DMSO removal showed that the effect of the parameters on DMSO removal followed the order Fe(2+) > H2O2 > pH. From the BBD prediction, the optimum conditions were pH 3, 5 mM of Fe(2+), and 60 mM of H2O2. The difference between the experimental value (98 %) and the predicted value (96 %) was not significant. The removal efficiencies of DMSO, chemical oxygen demand (COD), total organic carbon (TOC), and iron in the fluidized-bed Fenton process were higher than those in the traditional Fenton process.

Boosting H2O2 Activation for the Efficient Degradation of Dimethyl Sulfoxide-Containing Wastewater over Supported Niobia Catalysts

“…8 Bellotindos et al investigated the degradation of DMSO by using the Fenton process in a fluidized-bed reactor, and 98% DMSO was degraded after 120 min under the optimum conditions of pH 3, 5 mM Fe 2+ , 60 mM H 2 O 2 , and 1 mM DMSO. 9 Matira et al also studied the degradation of DMSO in the fluidized-bed Fenton process and confirmed that methanesulfinate, methanesulfonate, formaldehyde, and formate were the intermediates of DMSO degradation. 10 Among these intermediates, methanesulfonate is the most difficult to degrade, and it is recalcitrant to Fenton degradation and contributed most to the residual TOC.…”

“…Among these methods, the Fenton process is the most widely employed strategy for the oxidative removal of DMSO from wastewater. − For example, Luna et al investigated the degradation of DMSO in a double-cathode electro-Fenton reactor and found that the complete degradation of DMSO was obtained under experimental conditions of 5 mM DMSO, pH 2, 27 mM H 2 O 2 , 2.14 mM Fe 2+ , and 1.5 A current density after 120 min . Bellotindos et al investigated the degradation of DMSO by using the Fenton process in a fluidized-bed reactor, and 98% DMSO was degraded after 120 min under the optimum conditions of pH 3, 5 mM Fe 2+ , 60 mM H 2 O 2 , and 1 mM DMSO . Matira et al also studied the degradation of DMSO in the fluidized-bed Fenton process and confirmed that methanesulfinate, methanesulfonate, formaldehyde, and formate were the intermediates of DMSO degradation .…”

“…Researchers have tried many chemical methods to degrade DMSO, including UV/H 2 O 2 treatment, ozone-based advanced oxidation processes, TiO 2 -based photodegradation, Fenton reactions, − and electrochemical mineralization . Among these methods, the Fenton process is the most widely employed strategy for the oxidative removal of DMSO from wastewater. − For example, Luna et al investigated the degradation of DMSO in a double-cathode electro-Fenton reactor and found that the complete degradation of DMSO was obtained under experimental conditions of 5 mM DMSO, pH 2, 27 mM H 2 O 2 , 2.14 mM Fe 2+ , and 1.5 A current density after 120 min .…”

Solvent-induced competing processes in polycarbonate degradation: depolymerization, chain scission, and branching/crosslinking

“…It is reported that DMSO can generate radicals upon interacting with reactive oxygen species (ROS) or in the presence of a base. [66][67][68][69][70][71][72][73][74] The radical generation rate depends on temperature following the Arrhenius equation. Upon lowering the reaction temperature from 100 °C to 50 °C, the concentration of radicals decreased, and the number of polymer chain branching/ crosslinking events decreased.…”

“…DMSO can serve as an effective source to generate various radical species. [66][67][68][69][70][71][72][73][74] To facilitate the radical generation, [75][76][77][78][79] copper sulfide (CuS) nanoparticles (NPs) were synthesized and used as catalysts. The DMSO-generated radicals participated in the chain cleavage reaction, leading to competing processes of oligomerization and branching/crosslinking depending on the reaction temperature and solution heterogeneity.…”