Effects of pH, Initiator, Scavenger, and Surfactant on the Ozonation Mechanism of an Azo Dye (Acid Red-151) in a Batch Reactor

Oezbelge, Tuelay A.
Erol, Funda
In this study, an initiator (Fe2+) and a scavenger (CO32(-)) were used at different concentrations in a batch reactor to investigate the reaction mechanism of ozonation of a model azo dye, namely Acid Red-151 (AR-151). Also, the effect of a nonionic surfactant known as a major pollutant in many industrial wastewaters, namely polyethylene glycol (PEG), was observed on the degradation rate of AR-151. The experimental parameters and their ranges were: pH (2.5-10), initiator (0.8-50mg/L of Fe2+), surfactant (10-200mg/L of PEG), and scavenger (10-500mg/L of CO32-); the initial concentration of the azo dye was kept constant at 20mg/L in all the experiments. Results showed that decomposition of ozone was enhanced with increasing pH and increasing initiator (Fe2+) concentration at a scavenger concentration of 100 mg/L, when there is no dye in the medium. A scavenger concentration of 100 mg/L CO32- was not sufficient to terminate the chain reactions of ozone decomposition. It was concluded that the dominant mechanism in the degradation of AR-151 was its direct oxidation with ozone molecules in water. The data obtained for the dye and chemical oxygen demand (COD) removals and total oxidation rate constants at different operating conditions were assessed in order to estimate the possible contribution of dye-oxidation by free radicals.


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Particle-pellet approach was used for the analysis of selectivity in a consecutive reaction scheme. It was illustrated that the ratio of macro and micropore diffusion resistance (α) has a significant effect on selectivity especially for intermediate values of particle Thiele modulus. Increase of this ratio and increase of particle Thiele modulus yield lower selectivities for the intermediate product.
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The effect of micro- and nanometer-sized boron particles on boron-potassium nitrate (BPN) ignition composition was investigated in this paper. As a starting point, thermochemical calculations were made to determine the most promising ignition compositions. Both stoichiometric and fuel-rich formulations of BPN were produced to observe the performance variation due to boron content. Particle morphology of boron particles and the surface structure of the ignition compositions were investigated by SEM. The infl...
Effect of Alkyl Derivatization on Several Properties of N-Halamine Antimicrobial Siloxane Coatings
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Variation of alkyl substitution at position 5 on the hydantoin ring of a series of N-halamine siloxane derivatives has been employed to better understand the biocidal activities of these compounds for use in preparing antimicrobial coatings. The alkyl derivatization of the hydantoin ring at its 5 position, while an essentially constant chlorine loading is maintained at the I position, has shown that there is little dependence of the antimicrobial efficacy against Escherichia coli O157:H7 on the alkyl chain ...
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Impact of the nanoparticle size and concentration on the rheology of ethylene glycol based nanofluids containing nanoparticles of five different metal oxides is investigated. Particle mass concentrations ranged from 5 to 20 wt %. Types of the nanoparticles and their particle size are TiO2 (30 nm, 50 nm), MgO (20 nm, 40 nm), ZnO (10-30 nm, 35-45 nm, 80-200 nm), SiO2 (20-30 nm, 60-70 nm) and CuO (40 nm, 80 nm). A stress controlled rheometer fitted with a cone-and-plate system is employed for the rheological c...
Effect of fluorine substituted benzothiadiazole on electro-optical properties of donor-acceptor-donor type monomers and their polymers
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A series of trimeric monomers bearing thiophene donor units and fluorinated analogues of benzothiadiazole acceptor units was synthesized via donor-acceptor-donor approach and polymerized electrochemically in order to investigate the effect of fluorine atom on electro-optical properties of both monomers and their corresponding polymers. All monomers exhibited solvatochromic and fluorescent properties. The introduction of fluorine atom into the conjugated backbone increased the oxidation potentials. Upon movi...
Citation Formats
T. A. Oezbelge and F. Erol, “Effects of pH, Initiator, Scavenger, and Surfactant on the Ozonation Mechanism of an Azo Dye (Acid Red-151) in a Batch Reactor,” CHEMICAL ENGINEERING COMMUNICATIONS, pp. 39–55, 2009, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/65266.