Fenton Oxidation Kinetics and Intermediates of Nonylphenol Ethoxylates

Abstract

Removal of nonylphenol ethoxylates (NPEOs) in aqueous solution by Fenton oxidation process was studied in a laboratory-scale batch reactor. Operating parameters, including initial pH temperature, hydrogen peroxide, and ferrous ion dosage, were thoroughly investigated. Maximum NPEOs reduction of 84% was achieved within 6 min, under an initial pH of 3.0, 25°C, an H 2 O 2 dosage of 9.74 · 10 -3 M, and a molar ratio of [A modified pseudo-first-order kinetic model was found to well represent experimental results. Correlations of reaction rate constants and operational parameters were established based on experimental data. Results indicated that the Fenton oxidation rate and removal efficiency were more dependent on the dosage of H 2 O 2 than Fe 2 + , and the apparent activation energy (DE) was 17.5 kJ/mol. High-performance liquid chromatography and gas chromatograph mass spectrometer analytical results indicated degradation of NPEOs obtained within the first 2 min stepwise occurred by ethoxyl (EO) unit shortening. Long-chain NPEOs mixture demonstrated a higher degradation rate than shorter-chain ones. Nonylphenol (NP), short-chain NPEOs, and NP carboxyethoxylates were identified as the primary intermediates, which were mostly further degraded.

Redox activity and multiple copper(I) coordination of 2His–2Cys oligopeptide

“…Interaction between two different types of biochelators with two different types of transition metal ions can result in Fenton reactions. Since the Fenton reaction is a collection of redox reactions mediated by both Cu(I/II) and Fe(II/III), [43] the presence of iron chelators could be a contaminating electron source in these previous studies. [1,3,39] The Fe(II) titration of amb 2 supports this speculation (supplementary data, Fig.…”

Treatment of persistent organic pollutants in wastewater using hydrodynamic cavitation in synergy with advanced oxidation process

“…The attractiveness of the Fenton process in the generation of OH radicals for treatment of persistent organic pollutants can be attributed to its cost effectiveness, the abundance and nontoxic nature of the resulting iron oxides as well as environmental friendliness of hydrogen peroxide (Sharma et al 2011). Conversely, the narrow useful pH (2-3.5) range, consumption of large amounts of iron compounds, cost of peroxide and resultant formation of large amounts of iron sludge which are difficult to remove are the disadvantages of the Fenton process (Cui et al 2014). Besides, the produced stable Fe 3+ -complexes may reduce the efficacy of the treatment method (Natalija et al 2006).…”

“…It is an ideal adsorbent with strong reducing capacity for contaminants such as organic dyes, persistent pollutant, halogens and heavy metals in wastewater treatment plants (Lopez-Telleza et al 2011). A good number of publication have reported the degradation of persistent pollutants using nZVI in the treatment of contaminated water as a Bstand alone^ wastewater treatment method (Sirk et al 2009) or in combination with cavitation technology for the treatment of hydrocarbons in oil (Cui et al 2014). Cavitation is capable of improving the performance of the heterogeneous catalyst in AFP by breaking down the stable Fe 3+ -complex and making the Fe 3+ available for the regeneration of ferric ion.…”

“…Although the research into wastewater treatment with hydrodynamic cavitation is still at the infant level, it offers a simple reactor design, inexpensive and less cumbersome operation procedures in comparison with acoustic cavitation (Gogate and Patil 2015). Besides, the associated disadvantages in the stand alone AOPs such as production of large quantity of iron sludge and narrow effective pH range (2-3.5) in the Fenton process (Cui et al 2014) as well as lower mineralisation rate in hydrodynamic cavitation are completely eradicated in this hybrid combination of the two (Gogate and Patil 2015). Chakinala et al (2008) proved that the combination of hydrodynamic cavitation and the Fenton process is capable of achieving about 80% reduction in TOC after an hour of treatment time (Chakinala et al 2009).…”

Removal of dinitrotoluene from petrochemical wastewater by Fenton oxidation, kinetics and the optimum experiment conditions

“…The kinetic constants of Fenton oxidation to remove DNT were investigated and determined. Pseudo-firstorder kinetic model was made to determine the kinetic constants and represented by the following reaction [32]:…”