Degradation of 2-hydroxybenzoic acid by advanced oxidation processes

Abstract

-In this study, advanced oxidation processes (AOPs) such as the UV/H 2 O 2 and Fenton processes were investigated for the degradation of 2-hydroxybenzoic acid (2-HBA) in lab-scale experiments. Different [H 2 O 2 ]/[2-HBA] molar ratios and pH values were used in order to establish the most favorable experimental conditions for the Fenton process. For comparison purposes, degradation of 2-HBA was carried out by the UV/H 2 O 2 process under Fenton experimental conditions. The study showed that the Fenton process (a mixture of hydrogen peroxide and Fe 2+ ion) was the most effective under acidic conditions, leading to the highest rate of 2-hydroxybenzoic acid degradation in a very short time interval. This same process led to a six-fold acceleration of the oxidation rate compared with the UV/H 2 O 2 process. The degradation of 2-hydroxybenzoic acid was found to follow first-order kinetics and to be influenced by the type of process and the experimental conditions. The experimental results showed that the most favorable conditions for 2-HBA degradation by the

Influence of inorganic ions and selected emerging contaminants on the degradation of Methylparaben: A sonochemical approach

“…The aromatic hydroxylation of III results in the formation of dihydroxy benzoic acid (IV). These kind of compounds are reported as the major stable intermediates of hydroxy benzoic acids [49]. The decarboxylation reaction of this product will lead to the formation of dihydroxy phenol (V) followed by trihydroxy phenol (VI).…”

A dual perspective (conventional and solar-enhanced) on advanced oxidation processes for the treatment of Agave cocui vinasses

“…However, optimal pH values of around 7 have also been reported [17,33]. The inhibition of the Fenton process due to the influence of the pH might be explained by the following : (i) under an extremely low pH value (pH<2), the [Fe(H 2 O)] +2 formed reacts with H 2 O 2 , decreasing the production of OH • [34], (ii) the inhibition effect of the H + ions on OH • radicals assume higher importance under low pH values, (iii) Fe +3 and the H 2 O 2 reaction is inhibited under low pH conditions [35], (iv) at pH values higher than 4.5, the absence of H + inhibits the decomposition of the H 2 O 2 resulting in lower production of hydroxyl ions, (v) at pH values higher than 5, H 2 O 2 decomposes into water and oxygen; in addition, the formation of Fe complexes begins, deactivating the catalyzer [36], (vi) the oxidation potential of OH • decreases as the pH value increases. The H 2 O 2 amounts are a critical variable of the process, the OH • amount produced being directly dependent on it.…”

Advanced Oxidation Based Treatment of Soil Wash Water Contaminated with Sulfolane

“…Higher degradation rates are usually observed at higher hydrogen peroxide concentrations due to reactive radical species (hydroxyl radicals) generation through H 2 O 2 molecules decomposition [23]. Studies have reported that at high doses the excess H 2 O 2 did not enhance the degradation rate, sometimes even inhibit the reaction [24]. The negative impact of excess H 2 O 2 on degradation rates can be related to its scavenging effects [25,26].…”