Photo-Fenton Degradation of Carbofuran in Helical Tube Microreactor and Kinetic Modeling

Abstract

The photo-Fenton process is intensified for degradation of carbofuran by using a tubular microreactor coiled around a florescent light. The microreactor attained 7.5 times faster degradation rate compared to a batch reactor operated under a LED light. At the initial Fe 2+ concentration of 0.25 mM, the degradation rates in the batch reactor were fast at first, subsequently became slow, and afterward gradually increased with time regardless of light intensity. In the microreactor, the degradation rates appeared to decrease similarly to the firstorder reaction despite the same initial Fe 2+ concentration. A proposed kinetic model well fitted the results of both batch and microreactors by modeling that Fe 3+ is photoreduced in a complex in equilibrium with Fe 3+ and intermediates with carboxyl group decomposed from carbofuran.

The principle of detailed balancing, the iron-catalyzed disproportionation of hydrogen peroxide, and the Fenton reaction

“…If we disregard this concern, the consequences of this illegal loop in a mass-action mechanism can be explored by performing simulations of the loop based on the mechanism and parameters of a publication by Lin and Gurol 1998. 176 17,21,23,26,33,95,99,133,[176][177][178][179][182][183][184]187,189,190,193,195,197,198,200,203,204,206,207,211,218,219,[223][224][225]228 One of these shows the steps in the loop but then excludes them from the final model. 200 There are a few publications that use the inverse acid dependence in the first step of the loop (non-mass-action kinetics).…”

Kinetic Modeling of Advanced Oxidation Processes Using Microreactors: Challenges and Opportunities for Scale-Up

“…A kinetic investigation of photo-Fenton processes in a microreactor has been presented very recently [54]. In this work, the adopted experimental set-up is of the same type as the one independently used for UVC/H 2 O 2 investigations, but with some substantial differences.…”

“…Although some authors suggested the possibility of direct use of these devices for water treatment by numbering up units [25,42], this seems a fairly unrealistic and antieconomic scenario, with very few possible niche applications in the treatment of small volumes of water for specific applications. Only a limited number of papers have addressed the use of microreactors for the estimation of intrinsic parameters and mechanism identification, which can be used for the scale-up of AOPs for wastewater treatment, which, in fact, is the most promising application [9,11,12,23,[43][44][45][46][47][48][49][50][51][52][53][54]. In this sense, there is still extensive room for improvement and exploitation of this technology for the design and scale-up of such tertiary treatments.…”

Fe doped CeO2 nanocubes with the exposure of active (100) facets for photocatalytic ozonation of 4‐chlorophenol under solar irradiation

“…Nowadays, more and more refractory organic pollutants resistant to traditional treatment methods have been found in water 1, 2 . Advanced oxidation processes (AOPs), such as Fenton, 3 catalytic ozonation, 4 persulfate, 5 and photocatalysis, 6 can efficiently destroy those refractory organic molecules through radicals with high oxidability. In addition to the single advanced oxidation technology, combined processes have received widespread attention in recent years due to their excellent treatment efficiency, e.g., photocatalytic ozonation 7–9 .…”