Electro‐Fenton Oxidation of Salicylic Acid from Aqueous Solution: Batch Studies and Degradation Pathway

Abstract

This study investigated the removal of salicylic acid (SA) from aqueous solution by electro-Fenton (EF) and EF-like processes using graphite-graphite electrolytic system. Fe 0 , Fe 2þ , Fe 3þ ions were used as the Fenton reagent in the EF process and in the EF-like reactions, Cu 2þ , Mn 2þ , Ni 2þ were used as the same. The effect of various operating conditions on the effectiveness of EF process was investigated. The contribution of adsorption and electrosorption in the removal of SA was also investigated. According to the results, EF method can be used efficiently for the removal of SA by maintaining proper operating conditions. Fe 2þ was confirmed to be the most efficient catalyst among the metal ions that were tested. Maximum removal efficiency of 75.13% was obtained under optimal operating conditions after 8 h of electrolysis. Even though EF-like processes are also effective for the removal of SA from aqueous solutions, EF removal of SA was observed to be more efficient for the same. Gas chromatography-mass spectrometry (GC-MS) of SA solutions electrolyzed at optimal conditions was carried out. Degradation pathway was proposed from GC-MS.

NaHCO3 enhanced Rhodamine B removal from aqueous solution by graphite–graphite electro Fenton system

“…The main aim of this work is to study the feasibility of commercially available graphite as both electrodes in EF process. Our previous studies reported that the graphitegraphite EF system is an efficient electrolytic system for the removal of dyes [39][40][41] and salicylic acid [32,33] from aqueous solution and the advantage of graphite-graphite EF process was reported in our previous work [39]. But, a detailed investigation of enhancement in dye removal efficiency of graphite-graphite EF system with the addition of NaHCO 3 was not studied in detail in any one of the articles.…”

“…Since, OH Å is the second strongest oxidant known after fluorine and has a very high standard potential, it will non-selectively react with the organic pollutants, leading to its complete mineralization [21]. EF process was successfully applied for the degradation and removal of dyes [22][23][24][25][26], pesticides and herbicides [27][28][29], phenolic compounds [30][31][32][33], leachate [34], drugs [35,36], aniline [37], petrochemical wastewater [38] etc.…”

Electrochemical removal of pharmaceuticals from water streams: Reactivity elucidation by mass spectrometry

“…While the former species can be degraded by • OH in the bulk, the latter ones are more refractory. The quick photolysis of Fe(III)-carboxylate species, primarily of the major Fe(III)-oxalate complexes, under UVA light or sunlight in PEF or SPEF, respectively, explains the better performance of these methods in decontamination of water with pharmaceuticals [22,41]. The addition of Cu 2+ as co-catalyst in EF and PEF accelerates the destruction of carboxylic acids due to the parallel destruction of Cu(II)-carboxylate species [31].…”

“…When the drug contains N atoms, oxamic acid coming from the degradation of N-derivatives (e.g. acetamide) may also be formed [22,31,37,41]. Oxalic, oxamic and formic acids are directly converted into CO2 [7].…”

“…Reaction products are usually determined by GC-MS analysis of electrolyzed effluents [21,22,[30][31][32][33][34][35][36][37][38][39][40][41], although, recently, authors tended to use LC-MS as an alternative analytical technique [11,30,[42][43][44][45][46][47] because LC-MS may allow detection of a larger number of products, even ionic ones. Unfortunately, literature on the application of LC-MS to real pharmaceutical effluents is rather scarce [12,13].…”