scholarly journals Treatment of Bisphenol-A Using Sonication-assisted Photo-Fenton Hybrid Process

2019 ◽  
Vol 33 (1) ◽  
pp. 43-57 ◽  
Author(s):  
Meral Dükkancı

Sonication-assisted photo-Fenton oxidation of an endocrine disrupting compound, bisphenol-A (BPA), was studied under visible-light irradiation in the presence of a LaFeO3 perovskite catalyst. The effects of the parameters: initial BPA concentration ([BPA]0), H2O2 concentration ([H2O2]0), catalyst loading, initial pH of the BPA solution, and reaction temperature were studied on the sonication-assisted photo-Fenton oxidation of an aqueous BPA solution. The optimum conditions for the oxidation were determined to be: [BPA]0 = 10 ppm, [H2O2]0 = 4.8 mM, catalyst loading = 0.75 g L–1, pH = 2.6, temperature = 313 K. During all runs, sonication power of 40 W, visible lights power of 150 W+150 W, BPA solution volume (0.5 L), and stirring speed of 500 rpm were kept constant. Under these conditions, degradation of 56.3 %, COD removal of 50.9 %, and TOC removal of 15.6 % were achieved after 6 h of reaction. The small amount of iron that leached into the solution indicated high stability of the catalyst. The sonication-assisted photo-Fenton oxidation of BPA was described by the second order kinetics with an activation energy of 15.34 kJ mol–1. Toxicity tests were also performed and the results revealed that the intermediates formed in the sonication-assisted photo-Fenton oxidation of BPA were less toxic compared to the parent BPA molecule at a neutral pH value. However, the same interpretation was not valid at the acidic pH of 2.6.

Author(s):  
Yujie Wang ◽  
Kang Hu ◽  
Zhiyu Yang ◽  
Chenlu Ye ◽  
Xin Li ◽  
...  

Bisphenol A (BPA) produced from biomass is a typical endocrine disrupting compound that is carcinogenic and genotoxic and can be accumulated in water due to its extensive use and difficult degradation. In this study, the porous ZnO photocatalyst with core-shell structure and large surface area was successfully developed for the efficient photocatalytic degradation of BPA. The various effects of calcination temperatures, BPA concentrations, ZnO dosages, pH and inorganic ions on the degradation performance were systemically studied. The results showed that 99% degradation of BPA was achieved in 1 h using the porous ZnO calcined at 550°C under the conditions of 30 mg/L BPA, 1 g/L ZnO, and pH of 6.5. Besides, the inhibition effects of anions for the photocatalytic removal of BPA decreased in the order of H2PO4- > HCO3- > SO42- > Cl−, while the cations K+, Ca2+, and Na+ had little effect on the photocatalytic degradation of BPA. The results of scavenging experiments showed that h+, ·O2-, and e− played the key role in the photocatalytic degradation process. Finally, the main pathways of BPA degradation were proposed based on ten intermediates found in the degradation process. This work may provide a good guideline to degrade various endocrine disrupting compounds in wastewater treatment.


2018 ◽  
Vol 9 (1) ◽  
pp. 23
Author(s):  
Sondos Dbira ◽  
Nasr Bensalah ◽  
Moustafa Zagho ◽  
Ahmed Bedoui

In this work, the degradation and mineralization of Diallyl Phthalate (DAP) in water by Fenton oxidation was investigated. The effects of different experimental parameters including the initial pH, the hydrogen peroxide (H2O2) dose, the catalyst (Fe2+) dose, the iron source, and the DAP concentration on the rate and the yield of DAP degradation by Fenton oxidation were evaluated. DAP and its intermediates were quantified by high performance liquid chromatography (HPLC) analysis and the measurement of total organic carbon (TOC) during Fenton oxidation. The results obtained confirmed that hydroxyl radicals (HO•) generated from Fenton’s reaction were capable of completely eliminating DAP from water. Fenton oxidation of 100 mg/L DAP aqueous solution at pH = 3.2 required 1000 mg/L H2O2 and 50 mg/L Fe2+. Under these conditions, more than TOC removal exceeded 95% after 300 min Fenton oxidation. The competition kinetics method was used to determine an absolute rate constant of 7.26.109 M−1 s−1 for the reaction between DAP and HO• radicals. HPLC analysis showed that phthalic acid, 1,2-dihydroxybenzene, 1,2,4-trihydroxybenzene, maleic acid, formic acid and oxalic acid were the main intermediates formed during DAP degradation. Accordingly, a simple DAP degradation mechanism by the Fenton reaction was proposed. These promising results proved the potential of Fenton oxidation as a cost-effective method for the decontamination of wastewaters containing phthalates.


Author(s):  
Isil Gultekin ◽  
Valko Mavrov ◽  
Nilsun H. Ince

AbstractThe study reports the degradation of an endocrine disrupting compound- bisphenol A (BPA) by ozonation at slightly acidic pH with emphasis on the operational parameters (e.g. BPA concentration, ozone addition and mass transfer rate, contact time), reaction kinetics, rate constants and oxidation byproducts. It was found that the rate of BPA decay (pseudo-first order with respect to concentration) was accelerated with increased ozone addition rate and decreased BPA initial concentration. The profile of aqueous ozone concentration was such that it remained constant during 1-3 min of contact and increased thereafter. The bimolecular reaction rate constant was estimated using the steady state concentration of ozone and the value found was in good agreement with those reported in the literature for similar pH. Total mineralization was most rapid before complete conversion of BPA and much slower thereafter, implying low reactivity of the intermediate products with ozone. Mineralization was enhanced by alkalinization to pH 10.8, which facilitated the overall degradation process via the formation of radical species that were less selective than ozone. Byproducts of oxidation in successive order of formation were p-tert-butylphenol, hydroquinone, methyl-dihydrobenzofuran and n-butyl acetate, none of which are classified as endocrine disruptors.


2014 ◽  
Vol 1073-1076 ◽  
pp. 336-339
Author(s):  
Tian Qi Li ◽  
Hui Wang ◽  
Ya Qi Zhu ◽  
Zhao Yong Bian

Response surface methodology was applied to investigate the optimum degradation conditions of paracetamol using Ag/BiVO4 photocatalysts under the visible light irradiation. Experimental results show that the optimum degradation conditions were: catalyst dosage quantity was 80 mg, Ag-catalyst loading was 5%, and the initial pH value of the solution was 6, respectively. Under this condition, the degradation efficiency of paracetamol was 77.9% within 5 h under the visible light irradiation.


2012 ◽  
Vol 90 (12) ◽  
pp. 1414-1421 ◽  
Author(s):  
S.E. Lewis ◽  
A. Yokofich ◽  
M. Mohr ◽  
C. Kurth ◽  
R. Giuliani ◽  
...  

Bisphenol A (BPA) is an endocrine-disrupting compound that can enter aquatic systems through landfill leachate or wastewater effluent. Although impacts of BPA on vertebrates are well documented, its effects on invertebrates are less clear. Amphipods such as Gammarus pseudolimnaeus Bousfield, 1958 are often prevalent invertebrates in freshwater ecosystems and can provide a powerful invertebrate model system to investigate the endocrine-disruptive capabilities of BPA. However, techniques to assay hormone concentrations in amphipods, especially vertebrate-like steroid sex hormones, are not widespread. In this study, we (i) quantified estrogen concentrations in juveniles and in adult female amphipods; (ii) quantified testosterone concentrations in juveniles and in adult male amphipods; and (iii) delineated changes to estrogen and testosterone concentrations of adults and juveniles following a 9-day exposure to BPA at four levels: 0 (control), 10, 50, and 100 µg/L BPA. Tissue extracts from homogenized samples were analyzed for estrogen or testosterone concentrations via radioimmunoassay for each reproductive class of amphipod. Low concentrations of BPA significantly increased estrogen concentrations in adult females and in juveniles. Moderate and high concentrations of BPA significantly increased testosterone concentrations in adult males, and low and moderate concentrations of BPA significantly increased testosterone concentrations of juveniles.


2019 ◽  
Vol 21 (2) ◽  
pp. 1-10
Author(s):  
Jose Colina-Marquez ◽  
María Margarita Guerra ◽  
Rodinson Arrieta- Perez

Albendazole is an anthelmintic drug with antiangiogenic properties, which means that inhibits the development of new blood vessels. This causes a serious risk for the growth of fetus during pregnancy as a result. Heterogeneous photocatalysis has been proposed as an alternative for removal of this contaminant. In this study, a solar compound parabolic collector (CPC) photocatalytic reactor was modeled and simulated in order to describe the total organic carbon (TOC) degradation of commercial albendazole. The Six Flux Model approach (SFM) was used to estimate the Local Velocity Volumetric Rate of Photon Absorption (LVRPA) coupled with a Langmuir-Hinshelwood (L-H) kinetic model in order to describe the photocatalytic degradation of the TOC content of the contaminant and its photochemical oxidation products. The parameters of the L-H model were estimated from experimental data obtained with a catalyst loading of 0.6 g/l, initial pH of 5.0 and three different initial TOC concentrations of the commercial albendazole (159.95, 75.58 and 40 ppm). The rate constant (kT) and adsorption constant (K1), estimated from the parameter fitting, were 9.28×10-4 m1.5ppmW-0.5 s-1 and 3.02 × 10-2 ppm-1, respectively. The model was validated with experimental results, achieving a TOC removal of 40% with the lowest concentration of the contaminant. By simulating the process with different catalyst loadings, the maximum TOC removal was achieved with 0.21 g/L of TiO2.


2019 ◽  
Vol 79 (4) ◽  
pp. 712-712 ◽  
Author(s):  
G. P. Peteffi ◽  
J. D. Fleck ◽  
I. M. Kael ◽  
D. C. Rosa ◽  
M. V. Antunes ◽  
...  

Abstract Bisphenol A (BPA) is an emerging contaminant, regularly detected in aquatic ecosystems, considered as an endocrine disrupting compound (EDC). Caffeine is another chemical related to human activity, often found in surface waters. The objective of this study was to evaluate the ecotoxicological risk due to BPA and caffeine in water samples from the Sinos River basin, Rio Grande do Sul, Brazil. Water samples were collected at three sites monthly from May 9 th, 2016 to April 11th, 2017 (n = 36). BPA concentrations in water samples collected were in the range of not detected to 517 ng L-1 and caffeine concentrations in the range of 41.7 to 28,439.6 ng L-1. The concentration of BPA in the analyzed samples had a moderate correlation with caffeine (rs = 0.402). High ecotoxicological risk for BPA was characterized in 77.77% of samples, with 11.11% presenting medium and 11.1% presenting low risk. For caffeine 13.9%, 50% and 36.11% of the samples presented high, medium and low risk, respectively. Caffeine concentrations in water can be used as predictors of BPA concentrations above 10 ng L-1, the lower concentration of ecotoxicological risk, with specificity of 66.7% and sensitivity of 70.4%. The assessment of aquatic risks has shown that both investigated compounds pose risks to organisms in the studied surface waters, mouth of the Pampa stream, mouth of the Luiz Rau stream and catchment point for public supply in Lomba Grande.


2017 ◽  
Vol 19 (2) ◽  
pp. 72-77 ◽  
Author(s):  
Sahand Jorfi ◽  
Sudabeh Pourfadakari ◽  
Mehdi Ahmadi ◽  
Hamideh Akbari

Abstract Thermally activated persulfate efficiency for the treatment of a recalcitrant high TDS wastewater was investigated. The specific character of studied wastewater was high TDS content of around 23820 mg/L and BOD5/COD ratio of 0.07. Effective operational parameters including initial pH values of 3–9, reaction temperature of 40–80°C and persulfate concentrations of 0.5–5 g/L for COD removal were investigated in batch mode experiments. Removal efficiency was pH and temperature dependent. The COD and TOC removal of 94.3% and 82.8% were obtained at persulfate concentration of 4 g/L, initial pH value of 5 and temperature of 70°C after 180 min for initial COD concentration of 1410 mg/L. The pseudo first-order kinetic model was best fitted with COD removal (R2 = 0.94).


Sign in / Sign up

Export Citation Format

Share Document