Electrochemical oxidation of diethyl phthalate at two dimensional graphite sheet electrodes: optimization and analysis of degradation in water with HRMS

Abstract

Concentration of phthalates in the environment has been steadily increasing due to their high utilization rate and the inability of conventional wastewater and water treatment to remove them. Electrochemical oxidation at Boron doped diamond (BDD) was effective for phthalate removal but costly and unaffordable in many situations. Hence, we carried out the electrochemical oxidation of Diethyl Phthalate (DEP) at two dimensional graphite electrodes as a low cost alternative to oxidation at BDD electrodes. Optimization studies found that high concentrations of DEP (56-112 mg/L) can be effectively removed from water with acidic pH (pH 3), 60 mA/cm 2 current density, 81 cm 2 anode surface area and 10 mM sodium sulfate with 60 min treatment time. At 56 mg/L DEP concentration, COD and TOC removal were 92.5% and 70% respectively. FTIR studies were conducted to nd out whether any adsorption or electrosorption had taken place at the electrode surface. High performance liquid chromatography-photo diode array (HPLC-PDA) analysis of 84 mg/L DEP solution treated at optimal conditions found 97.3% removal of DEP. High resolution mass spectrometry (HRMS) studies utilizing Ultra performance liquid chromatography quadrupole time of ight mass spectrometry (UPLC-Q-ToF-MS) were conducted for nding the degradation byproducts and possible degradation pathway was proposed with the degradation mechanism.

Anodic oxidation of esomeprazole in water by carbon coated titanium (C/Ti) electrode: Optimization and degradation analysis

“…Optimization pH and electrolyte concentration pH of a solution determines the dominance of H + and OH-ions in a sample. Often, the presence of H + and OH-ions in a solution determines the mechanism and oxidation e ciency of an electrochemical treatment system [20,21]. In this context, COD analysis was conducted to nd out the effect of variable pH in the degradation of ESO.…”

“…pH 3 was observed to be the optimal condition for maximum COD removal from ESO. The presence of sodium sulfate along with acidic condition might have created sulfate radicals that degraded ESO [20,21]. The mechanism involved is given from Eq.…”

Catalytic oxidation processes for the degradation of Progesterone using V2O5 catalyst and C/Ti anode: Optimization and degradation dynamics

“…Current density is directly responsible for the production of reactive oxygen species in electrochemical oxidation. Removal of COD from water and wastewater sources have been studied by various scienti c articles for understanding the effect of current density on degradation of emerging contaminants [22,30,31].…”

“…At basic pH, higher production of hydroxide ions might have competitively inhibited the production of hydroxyl radicals resulting in considerable decrease in TOC and COD removal rates at pH 9 [19,37]. Irrespective of the initial pH utilized, nal pH of the treated samples uctuated between 3.2 and 4.2 pointing to the formation of organic acid groups during the oxidation of PGT [15,26,30].…”

“…Interestingly, PC + EC(Visible) fared worse than EC tempting an assumption that visible light source had an inhibitory effect on electrocatalytic oxidation of PGT whose reason is unknown. c. Spectral studies Demonstration of degradation mechanism and pathway of a particular contaminant is of signi cant interest for organic and environmental chemistry to analyze the e cacy of a particular process [27][28][29][30][31]. Hence, HRMS studies with UPLC-Q-TOF-MS was utilized to nd out the degradation byproducts, identify the mechanisms involved and propose the degradation pathway of PGT.…”