Photo-Fenton Degradation of the Herbicide 2,4-Dichlorophenoxyacetic Acid in Laboratory and Solar Pilot-Plant Reactors

Abstract

A theoretical and experimental study of a pilot-plant solar reactor for the photo-Fenton degradation of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution is presented. Initially, a kinetic model is proposed to obtain the reaction rates of 2,4-D, the main intermediate (2,4-dichlorophenol), and the hydrogen peroxide. The kinetic study was performed in a well-stirred tank laboratory reactor. The effects of ferric salt initial concentrations, hydrogen peroxide to 2,4-D initial concentration ratios, reaction temperatures, and radiation levels are studied. The proposed kinetic model and the experimental data are used to estimate the kinetic parameters, applying a nonlinear regression procedure. Afterward, the kinetic model is used to predict the reactant concentrations during the photo-Fenton degradation in a pilot-plant solar reactor designed to capture the UV/visible/IR solar radiation. The solar reactor was able to reach a complete degradation of the 2,4-D and 2,4-dichlorophenol after 60 min, and a total organic carbon conversion of 98.9% after 210 min.

Modeling and optimization of photo-Fenton degradation of 2,4-D using ferrioxalate complex and response surface methodology (RSM)

“…In the present study, two filter combinations were analyzed: (a) water filter, air mass filter AM0 and air mass filter AM1.5 Direct, and (b) water filter, air mass filter AM0 and air mass filter AM1 Direct, which will be called F-1.5D and F-1D, respectively. The selection was made regarding the radiation level in a pilot plant-solar reactor quantified in previous essays, considering the period of maximum incident solar radiation (noon) for clear summer days and standard relative humidity conditions (50e60%), in Santa Fe city, Argentina (Conte et al, 2012).…”

Recent Overview of Solar Photocatalysis and Solar Photo-Fenton Processes for Wastewater Treatment

“…Since after certain time and under experimental conditions, treated dye solutions became enough biocompatible to be fully biodegraded in the IBR reactor, attaining residual DOC values close to the 20 mg L −1 corresponding to biomass metabolites. There are several papers devoted to oxidize many organic contaminants (like microcontaminants, herbicides, textile dyes, landfill leachates, and emergent contaminants) by solar photo-Fenton and solar photoelectro-Fenton (as depicted in Tables 1 and 2) using solar compound parabolic collectors and solar pilot reactors [2,52,53,82,88,[100][101][102][103][104][105][106][107][108]. Most of these studies claimed that photo-Fenton enhanced the degradation of the organic compounds achieving over 50% TOC removal.…”

“…The solar photo-Fenton degradation of the 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide in solar pilot-plant reactors was carried out by Conte et al [100]. These authors proposed a kinetic model to predict the reactant concentrations during the degradation and reported that the solar reactor was able to reach complete degradation of both the 2,4-D and the main intermediate (2,4-dichlorophenol) at 60 min with 98.9% of total organic carbon (TOC) conversion at 210 min.…”

Fenton Processes as an Alternative to the Removal of Endocrine Disruptors and other Environmental Pollutants

“…47 50 A aplicação de processos Fenton na remoção de herbicidas e outras substâncias usadas no controle de pragas ambientais já foi amplamente relatada na literatura. [51][52][53][54] No caso dos herbicidas, a maior ocorrência e acumulação se dão em solos, pois estas substâncias são altamente lipofílicas. No entanto, a lixiviação do solo por água de chuva, marés, ou ainda, mudança no leito de rios, pode provocar o arraste dos herbicidas para os compartimentos aquáticos, o que levaria à contaminação dos mesmos e a necessidade de remoção dos herbicidas de ambientes aquáticos.…”