Abatement of 1,2,4-Trichlorobencene by Wet Peroxide Oxidation Catalysed by Goethite and Enhanced by Visible LED Light at Neutral pH

Abstract

There is significant environmental concern about chlorinated organic compounds (COCs) in wastewater, surface water, and groundwater due to their low biodegradability and high persistence. In this work, 1,2,4-trichlorobenzene (124-TCB) was selected as a model compound to study its abatement using wet peroxide oxidation at neutral pH with goethite as a heterogeneous catalyst, which was enhanced with visible monochromatic light-emitting diode (LED) light (470 nm). A systematic study of the main operating variables (oxidant and catalyst concentration and irradiance) was accomplished to investigate their influence in the abatement of 124-TCB in water. The reaction was carried out in a well-mixed reactor of glass irradiated by a visible LED light. The hydrogen peroxide concentration was tested from 0 to 18 mM, the goethite concentration within the range 0.1–1.0 g·L−1 and the irradiance from 0.10 to 0.24 W·cm−2 at neutral pH. It was found that this oxidation method is a very efficient technique to abate 124-TCB, reaching a pollutant conversion of 0.9 when using 0.1 g·L−1 of goethite, 18 mM of H2O2, and 0.24 of W·cm−2. Moreover, the system performance was evaluated using the photonic efficiency (ratio of the moles of 124-TCB abated and the moles of photons arriving at the reactor window). The maximum photonic efficiencies were obtained using the lowest lamp powers and moderate to high catalyst loads.

Application of Chelating Agents to Enhance Fenton Process in Soil Remediation: A Review

“…A simplified reaction mechanism showing the reversible binding between the ligand and iron (Fe(II)/Fe(III)), which results in the formation of a complex (expressed as Fe(II)-L and Fe(III)-L, respectively), is proposed in Equations (12) and (13). It should be considered that the complexation of Fe species with ligands is more complicated than shown, and a wide variety of complexes, such as FeL 2, FeHL, FeHL 2 , etc., can be formed.…”

“…Fe(II) + L Fe(III)-L (12) Fe(III) + L Fe(III)-L (13) In a simplified reaction scheme of chelate-modified Fenton (MF), the Fe-L complexes formed (Equations ( 12) and ( 13)) would decompose H 2 O 2 to generate radical species (hydroxyl and hydroperoxyl radicals) (Equations ( 14) and ( 15)), equivalent to classical Fenton reactions (Equations ( 1) and (2), respectively), being the catalytic regeneration (Equation (15)) the limiting stage of the process. However, in the presence of most organic CAs, it has been suggested that H 2 O 2 was unlikely to reduce complexed iron, and the reduction of Fe(III)-L was mainly produced through O 2…”

“…The interest in using heterogeneous catalysts in the Fenton process (known as catalytic wet peroxide oxidation process, CWPO) has significantly increased in recent times [12]. CWPO uses natural iron-containing materials [12][13][14], supported catalysts with high surface area-supports (pillared clays, zeolites, silica, activated carbon, etc. ), allowing the dispersion of the active phase (mainly Fe, but also Cu, Mn, Au, etc.)…”

Abatement of Naphthalene by Persulfate Activated by Goethite and Visible LED Light at Neutral pH: Effect of Common Ions and Organic Matter

“…However, the visible light used was source Hg or Xe lamps, which need complicated cooling and are toxic. For this reason, commercial visible light-emitting diode lamps (VIS LED) have been recently proposed as an innovative light source for the removal of organic pollutants from water at a neutral pH using natural iron minerals and hydrogen peroxide as the oxidant [19]. However, the efficiency of H 2 O 2 decreased in the presence of high carbonate contents in water due to non-productive reactions [20][21][22][23], and the use of PS is recently gaining attention.…”

Evaluation of Goethite as a Catalyst for the Thermal Stage of the Westinghouse Process for Hydrogen Production

“…Considering this background, in this work, goethite has been evaluated as a catalyst for sulfuric acid thermal decomposition. Goethite is a cheap material, naturally stable mineral, and widespread iron oxide [23][24][25]. It consists of an iron (III) oxide-hydroxide (α-FeO(OH)) found as a sediment in nature.…”