Optimization of the Photochemical Degradation of Textile Dye Industrial Wastewaters (original) (raw)
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Decolorization of textile wastewater by photo-Fenton oxidation technology
Chemosphere, 2000
This paper describes the use of photo-fenton process for color removal from textile wastewater stream. The wastewater sample to be treated was simulated by using colorless polyvinyl alcohol (PVA) and reactive dyestu of R94H. As a result, the hydroxyl radical (HOá) oxidation can eectively remove color, but the chemical oxygen demand (COD) was removed in a slight degree. The color removal is markedly related with the amount of HOá formed. The optimum pH for both the OHá formation and color removal occurs at pH 3±5. Up to 96% of color can be removed within 30 min under the studied conditions. Due to the photoreduction of ferric ion into ferrous ion, color resurgence was observed after 30 min. The ferrous dosage and UV power aect the color removal in a positive way, however, the marginal bene®t is less signi®cant in the higher range of both. PVA as the major background COD of a textile wastewater stream inhibits the color removal insigni®cantly as its concentration increases. Ó
2016
In this study Advanced oxidation process using Fenton reagents is considered for the application of textile dye-house wastewater treatment. A representative basic dye-house wastewater sample has been brought from K.K. Textile Factory and its characteristic is analyzed and the result shows that dye-house wastewaters, containing basic dyes, are hazardous to the environment since their COD & BOD values are higher than the free discharge limit values and also they are highly colored even at the lower dye concentration operation cases. After characterizing the wastewater, advanced oxidation of a Basic Blue 41 dyes using solar -Fenton treatment was investigated in batch experiments using Box–Behnken statistical experiment design and the response surface analysis. Dyestuff, H2O2 and Fe2+ concentrations were selected as independent variables in Box– Behnken design while color and COD removal were considered as the response functions. Color removal increased with increasing H2O2 and Fe2+ con...
Enhancing the Fenton Process by Uv Light Applied in Textile Wastewater Treatment
Environmental Engineering and Management Journal
Nowadays, an efficient wastewater management involves the use of advanced treatment technologies able to decompose hardly biodegradable compounds with reasonable costs at the lowest possible environmental impact. In our work we used one of the most efficient advanced wastewater treatment, the Fenton reaction and its photo-assisted version. The hydrogen peroxide was the oxidizer; despite its relatively high cost, its high activity in oxidizing of a large variety of organic persistent pollutants in the presence of Fe 3+ ions as catalyst, makes it an alternative which is worth to be considered even in practical medium scale systems. The Fenton and photo-Fenton oxidation were performed using a model dye, the xanthene-type Rhodamine 6G, widely used in a series of biotechnology applications, but having major drawbacks when released in natural water flows, mainly mutagen and carcinogen effects. Therefore, a parametric case study was performed in order to define the optimal operating parameters (the pH value, the hydrogen peroxide concentration and the iron catalyst concentration). The oxidative degradation of Rhodamine 6G by Fenton reaction was more effective when combined with UV irradiation. Each parameter of the oxidative treatment is essential for the color and TOC removal. The optimal values found for the total color degradation and mineralization of the dye were as follows: 16 ppm Fe 3+ , 100 ppm H 2 O 2 and pH of 4.5.
Fenton and Photo-Fenton Oxidation for the Remediation of Textile Effluents: An Experimental Study
Wiely , 2019
The decolorization efficiency of Acid Orange 3 (AO3) was investigated using Fenton (Fe 2+ /H 2 O 2) and photo-Fenton (Fe 2+ /H 2 O 2 /UV) processes. The outcome of different parameters, i.e., effect of pH, contact time, Fe +2 concentration, H 2 O 2 dose, initial dye concentration, and temperature on the decolorization process, was investigated and maximum degradation (90%) was achieved at pH 3, 0.5 mM Fe +2 , 6 mM H 2 O 2 at 50°C with 50 mg/L initial dye concentration at constant shaking speed of 100 rpm in 30 min. The effect of photo-Fenton (Fe +2 / H 2 O 2 /UV) treatment was evaluated by irradiating the dye solution at 365 nm at 261, 243, 212, 176 and 96 counts/sec intensities and resultantly, the decoloriza-tion efficiency was reached up to 97% of AO3 dye. The dye degradation data were fitted to different kinetics models and Behnajady-Modirshahla-Ghanbery (BMG) model best explained the AO3 degradation experimental data. Results revealed that the Fenton oxidation process would be used for the treatment of textile effluent containing waste dyes.
Degradation and sludge production of textile dyes by Fenton and photo-Fenton processes
Dyes and Pigments, 2007
The degradation and decolorization of direct dye (Everdirect supra turquoise blue FBL), acidic dye (Isolan orange S-RL) and vat dye (Indanthrene red FBB) have been investigated by Fenton and UV/Fenton processes. The effects of solution pH, Fe 2þ dosages and H 2 O 2 dosages have been studied by jar-test experiments. A comparative study for Fenton and UV/Fenton reactions by photoreactor has also been carried out by scale-up the optimum conditions, obtained through jar-test experiments. Fenton process is highly efficient for color removal for three dyes tested and for TOC removal of FBB and FBL. UV/Fenton showed slighter increase in treatment efficiency than that of Fenton process for both FBB and FBL dye solutions. S-RL improved much more TOC removal% by UV-irradiation. Sludge productions were compared for FeCl 3 -, FeSO 4coagulation and Fenton reaction in order to prove the dual role of FeSO 4 in Fenton process.
Separation and Purification Technology, 2017
This study reports an integrated treatment strategy for synthetic polyester-cotton dyeing wastewater, combining biological and photochemical oxidation processes. The biodegradability of all constituents, dyes and dyeing auxiliary products, present in the synthetic polyester dyeing textile wastewater were firstly analysed through a Zahn-Wellens test. More than 80% of the constituents are easily biodegradable, being possible to achieve its complete removal by biological oxidation. Consequently, the synthetic wastewater was firstly subject to a biological oxidation, achieving a dissolved organic carbon (DOC) removal of 76%, resulting in a bio-treated wastewater with 84 mg L À1 of DOC. The colour reduction was less than 5% Platinum-Cobalt Scale (Pt-Co scale), 9% (DFZ 436nm), 3% (DFZ 525nm) and 0% (DFZ 620nm), (DFZ-DurchsichtFarbZahl, visual colour number in German). Thus, UVC/H 2 O 2 and photo-Fenton (PF) oxidation processes were used as a polishing step for the decolourisation of bio-treated textile wastewater. The PF reaction did not promote wastewater decolourisation as shown by the colour indicators monitored. Moreover, the addition of oxalic acid did not result in an enhancement of the PF reaction. On the other hand, the photolysis of hydrogen peroxide using UVC radiation showed decolourisation efficiencies of 71% (Pt-Co method), 86% (DFZ 436nm) and 97% (DFZ 525nm) and more than 40% of mineralisation, consuming 14.1 mM H 2 O 2 and 3.1 kJ UVC L À1 of energy dosage (time = 95 min; 6 W UVC lamp; natural pH = 8.4; T = 30°C). The effect of hydrogen peroxide dosage, lamp power, solution pH and temperature on the UVC/H 2 O 2 efficiency for wastewater decolourization was evaluated. During the photochemical reaction some low-molecular-weight carboxylic acids were detected, as oxalic acid, maleic acid and tartaric acid. The integrated treatment strategy was able to achieve a wastewater quality in agreement with the discharge limits imposed by legislation, and the total operating costs was 2.33 € m À3 .
Chemical Engineering Journal, 2014
Both photo-Fenton oxidation and the combination of aerobic Sequencing Batch Reactor (SBR) + photo-Fenton oxidation were investigated in a bench-scale study to degrade and reuse, a real textile wastewater with TOC = 390 mg•L-1 , COD = 1560 mg•L-1 O 2 and Escherichia coli = 80000 CFU•mL-1 , for dyeing processes according to RD 1620/2007 (Spanish Normative for wastewater reclamation and reuse) and required water qualities for internal reuse. The independent variables considered for the optimization of the oxidative process were temperature, H 2 O 2 and Fe (II) concentrations. The best results were obtained when applying photo-Fenton process as a polishing step. In this case, the previous aerobic biological treatment conducted by using a SBR with HRT = 1 day, gave 75 % TOC reduction after 25 cycles. Subsequently, the coupled photo-Fenton process applied under optimal conditions ([Fe (II) = 66.5 mg•L-1 ; [H 2 O 2 ] = 1518 mg•L-1 ; T = 25 ºC and pH = 2.7) gave final COD and TOC reductions of 97 and 95 % respectively; Escherichia coli accomplished RD 1620/2007. However, this treated water could not be 100% used and was further conditioned by reverse osmosis accomplishing suitable water qualities for internal reuse. This resultant water was used in dyeing processes and gave similar dyeing results in terms of K/S than those obtained by using fresh water.
Catalysts
A photo-Fenton process using a local iron oxide as a natural catalyst was compared to Fenton and UV/H2O2 advanced oxidation processes for degrading crystal violet (CV) dye in aqueous solutions. The catalyst was characterized by transmission electron microscopy (TEM), energy dispersive X-ray microanalysis (EDX), Fourier transform infrared spectroscopy (FT-IR), Raman spectrum, X-ray diffraction (XRD), UV-vis spectroscopy, and Brunauer–Emmett–Teller (BET) analysis. The optical properties proved that the catalyst represents a good candidate for photocatalytic activity. The impact of different parameters (catalyst dose, initial CV concentration, initial H2O2 concentration, pH) on the photo-Fenton efficiency was evaluated. A photo-Fenton process operated under UVC light irradiation, at spontaneous pH, with 1.0 g/L of catalyst and 30 mg/L of H2O2 was the most effective process, resulting in 98% CV dye removal within 3 h. LC-MS and ion-chromatography techniques were used to identify demethy...
Batch and Continuous Photo-Fenton Oxidation of Reactive-Red Dye from Wastewater
This paper aims to investigate the ability of photo-Fenton technology to remove Reactive Red dye (RR-dye) from wastewater using batch and continuous operating modes. The batch mode of photo-Fenton removal of organic content was conducted under the influence of solution pH (3-10), hydrogen peroxide (25-100 ppm), irradiation time (20-90 min), ferrous sulphate (5-20 ppm), and temperature (25-60 °C). For comparison, the continuous treatment was conducted under the influence of the flow rate of the contaminated solution (10, 20, 30, 40, and 50 mL/min). The results revealed that the treatability of the batch mode was more effective compared to the continuous mode. In the batch process, the organic contaminant was completely removed compared to that of 82% obtained when the continuous system was performed. The optimization process showed that the optimal values of the operating variables in the case of the batch removal of RR-dye were 3, 78 ppm, 90 min, 20 ppm, and 60 °C for pH, hydrogen peroxide, irradiation time, ferrous sulphate, and temperature, respectively. Moreover, the reversion F-value was 21.69, the probability P value was less than 0.001, and the correlation coefficient was (R 2 = 0.9455), which illustrative the significance of the model obtained for the batch process.