Sonochemical Degradation of Rhodamine B Using Oxidants, Hydrogen Peroxide/Peroxydisulfate/Peroxymonosulfate, with Fe²⁺ Ion: Proposed Pathway and Kinetics

Abstract

This article addresses the sonochemical degradation of Rhodamine B (RB), a recalcitrant textile organic dye. The relative influence of extent of radical production by the cavitation bubbles and radical scavenging (or conservation) on the overall degradation of RB was assessed. Degradation of RB at different experimental conditions, such as pH, gases (air, argon [Ar], oxygen, and nitrogen), hydrogen peroxide (H 2 O 2 ), peroxymonosulfate (PMS), peroxydisulfate (PDS), ferrous sulfate, and novel Fenton-like reagents (H 2 O 2 + ferrous sulfate, PDS + ferrous sulfate, and PMS + ferrous sulfate), was studied. Experimental results revealed that sonochemical degradation of RB is governed by the extent of utilization of HOc radicals. Ar-bubbled solution that produces higher HOc radicals gave a higher color-removal rate than other gases. Further, higher color removal was observed at solution pH of 3. Of all the experimental conditions studied, novel Fenton-like reagent, that is, PMS + ferrous sulfate-added solution, gave complete color removal. Mineralization study also revealed that higher removal of total organic carbon was attained at the condition of PMS with ferrous sulfate (pH 3) than with other experimental conditions. This result has been attributed to synergistic effects of HOc radicals and sulfate radicals providing effective interaction with the dye molecule. Degradation intermediates of RB through LCMS/GCMS analysis were also provided to support the degradation pathway.

Adsorption of Rhodamine B from Aqueous Solution by Goat Manure Biochar: Kinetics, Isotherms, and Thermodynamic Studies

“…Thermodynamic parameters such as Gibbs free energy change (∆G°), enthalpy change (∆H°) and entropy change (∆S°) for RhB adsorption onto GMB600 were calculated as Eqs. (9) and (10):(9) (10) …where R is the ideal gas constant (8.314 J/(mol•K)), T is the Kelvin temperature (K), ∆G° is the Gibbs free energy change (kJ/mol), ∆H° is the enthalpy change (kJ/mol), ∆S° is the entropy change (kJ/(mol•K)), and K d is the thermodynamic equilibrium constant.…”

“…At present, researchers have tried a number of methods to remove RhB dye from aqueous solution, such as adsorption [6,7], the electro-Fenton process [8], photodegradation [9], sonochemical degradation [10] and membrane separation [11]. Among them, adsorption has been regarded as one of the most potential methods and widely favored by researchers because of its advantages such as convenient operating conditions, good treatment effects and an abundant source of raw materials.…”

Strategies for Improving the Performance and Application of MOFs Photocatalysts

“…The heterogeneous Fenton reaction catalyzed by Fe‐MOFs has been discussed in the section 2.4 of this paper. It is worth noting that the Fenton reaction of peroxymonosulfate as an oxidant had been widely investigated by researchers . Various transition metal‐based materials (oxides, MOFs, bimetals, carbides) are widely used as Fenton‐like reaction catalysts to activate peroxymonosulfate.…”

“…It is worth noting that the Fenton reaction of peroxymonosulfate as an oxidant had been widely investigated by researchers. [153][154][155] Various transition metal-based materials (oxides, MOFs, bimetals, carbides) are widely used as Fenton-like reaction catalysts to activate peroxymonosulfate. The heterogeneous Fenton reaction of Fe-MOFs with other oxidizing species are expected to be develop in recent years.…”

Sono‐photo‐assisted heterogeneous activation of peroxymonosulfate by Fe/CMK‐3 catalyst for the degradation of bisphenol A, optimization with response surface methodology

“…This is one of the reduction-oxidation reactions, in which the metal ion transmits an electron, and it is successfully applied in degradation of various pollutants. The basis of these processes is the production of highly reactive radicals such as hydroxyl (OH • ) which have remarkable capability for degradation of the pollutants (Kurukutla, Kumar, Anandan, & Sivasankar, 2015;Shokoohi et al, 2018). Today, the application of AOPs based on sulfate (SO ⋅− 4 ) radicals has found great popularity due to the excellent characteristics of this radical including higher redox potential (E 0 = 2.5-3.1 V), longer half-life, greater oxidation ability, and higher degradation efficiency for most organic contaminant over a wide pH range (4-9) (Devi, Das, & Dalai, 2016;Ghanbari, Moradi, & Gohari, 2016).…”