Solar photo-Fenton treatment of winery effluents in a pilot photocatalytic reactor (original) (raw)
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Applied Catalysis B: Environmental, 2010
A mixture of five commercial pesticides (Vydate ® , Metomur ® , Couraze ® , Ditimur-40 ® and Scala ®) commonly used in intensive agriculture has been selected as an example of highly toxic, non-biodegradable wastewater to be treated by solar Photo-Fenton. The effect of the total concentration of organics as dissolved organic carbon (100-500 mg/L), operating temperature (25-50 • C), dissolved iron concentration and their relationship to different process efficiency parameters (mineralization rate, hydrogen peroxide consumption and treatment time) were evaluated. Experiments were carried out under sunlight in a pilot plant. It consists of four compound parabolic collectors (CPCs) and a total volume of 75 L. From the results of the study it can be concluded that solar plants should be designed for operating at temperatures below 45 • C to avoid significant loss of iron. H 2 O 2 should be carefully dosed during the photo-Fenton treatment to avoid its continued excess and inefficient use.
Journal of Hazardous Materials, 2007
This paper reports on the combined solar photo-Fenton/biological treatment of an industrial effluent (initial total organic carbon, TOC, around 500 mg L −1 ) containing a non-biodegradable organic substance (␣-methylphenylglycine at 500 mg L −1 ), focusing on pilot plant tests performed for design of an industrial plant, the design itself and the plant layout. Pilot plant tests have demonstrated that biodegradability enhancement is closely related to disappearance of the parent compound, for which a certain illumination time and hydrogen peroxide consumption are required, working at pH 2.8 and adding Fe 2+ = 20 mg L −1 . Based on pilot plant results, an industrial plant with 100 m 2 of CPC collectors for a 250 L/h treatment capacity has been designed. The solar system discharges the wastewater (WW) pre-treated by photo-Fenton into a biotreatment based on an immobilized biomass reactor. First, results of the industrial plant are also presented, demonstrating that it is able to treat up to 500 L h −1 at an average solar ultraviolet radiation of 22.9 W m −2 , under the same conditions (pH, hydrogen peroxide consumption) tested in the pilot plant.
Recent Overview of Solar Photocatalysis and Solar Photo-Fenton Processes for Wastewater Treatment
International Journal of Photoenergy, 2017
This literature research, although not exhaustive, gives perspective to solar-driven photocatalysis, such as solar photo-Fenton and TiO2 solar photocatalysis, reported in the literature for the degradation of aqueous organic pollutants. Parameters that influence the degradation and mineralization of organics like catalyst preparation, type and load of catalyst, catalyst phase, pH, applied potential, and type of organic pollutant are addressed. Such parameters may also affect the photoactivity of the catalysts used in the studied solar processes. Solar irradiation is a renewable, abundant, and pollution-free energy source for low-cost commercial applications. Therefore, these solar processes represent an environmentally friendly alternative mainly because the use of electricity can be decreased/avoided.
Photo-Fenton degradation of wastewater containing organic compounds in solar reactors
Separation and Purification Technology, 2004
In this work, the photo-Fenton oxidation of phenol in aqueous solutions has been investigated using Fe 2+ , H 2 O 2 and UV-visible light (sunlight). Laboratory-scale experiments were carried out using solar reactors of two different configurations: (1) a concentrating parabolic trough reactor (PTR) and (2) a non-concentrating thin-film reactor. Global solar irradiance was measured during the experiments. Additional laboratory experiments were carried out in an annular photochemical reactor using an artificial light source, at the same experimental conditions. The results indicate that the photo-Fenton process using solar irradiation is an effective treatment for industrial wastewater containing phenol. At low contaminant concentration (TOC 0 = 100 ppm), more than 90% of the total organic carbon content of the initial phenol solution could be converted to inorganic carbon within about 3 h of irradiation, using artificial light or sunlight (even on cloudy days), in reactors of different geometry. At moderate or higher phenol concentrations (TOC 0 = 550 or 1000 ppm), the results indicate satisfactory TOC removal (45-55%) at reasonable degradation rates. Experiments under different insolation conditions suggest a direct linear dependence of the organic carbon removal on the accumulated sunlight energy reaching the system. Solar light can be used either as a complementary or alternative source of photons to the process.
Solar Energy, 2005
The elimination of aromatic compounds present in surface water by photo-Fenton with sunlight as the source of radiation was studied. The concentrations of Fe 3+ and H 2 O 2 are key factors for this process. A solar simulator and a prototype parabolic collector were used as laboratory-scale reactors to find the parameters of those key factors to be used in the CPC (compound parabolic collector) pilot plant reactor. The initial mineralization rate constant (k obs ) was determined and evaluated at different Fe 3+ and H 2 O 2 concentrations to find the best values for maximum efficiency. In all the experiments the mineralization of an aqueous phenol solution was described by assuming a pseudo-first-order reaction. The intrinsic kinetic constants not dependent on the lighting conditions were also estimated for scale-up.
Asia-pacific Journal of Chemical Engineering, 2009
Two chemical processes, Fenton and photo-Fenton, were tested separately for the treatment of vinasse, which was generated from an alcohol distillery process. In order to evaluate the processes effectiveness, four independent variables viz. SCOD concentration, initial pH, H2O2 and FeSO4 dosage were applied. Experiments were conducted based on a central composite design (CCD) and analyzed using response surface methodology (RSM). UV radiation for 80 min was applied in each experiment during the photo-Fenton process. Two modified quadratic equations were used for data fitting. The most significant model terms in the processes were found to be the initial chemical oxygen demand (COD) concentration and the initial pH. A higher removal efficiency was achieved in the photo-Fenton process compared to Fenton alone. The efficiency varied from 18 to 97% for the photo-Fenton process, while it was in the range of 5–47% for Fenton process. The R2 value of the models (R2 > 0.97) shows a very high degree of correlation between the parameters. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Photo-Fenton Treatment of Actual Agro-Industrial Wastewaters
Industrial & Engineering Chemistry Research, 2011
In this work, UV/H 2 O 2 treatment of actual pulp and paper mill wastewater (PPMW) was investigated. To determine optimal conditions, the effects of some experimental parameters (initial pH, initial H 2 O 2 concentration, temperature, and organics load) on the UV/H 2 O 2 process efficiency in terms of absorbance at 330 and 281 nm and chemical oxygen demand (COD) and total organic carbon (TOC) removals were studied. The results show that the UV/H 2 O 2 system leads successfully to the almost-complete elimination of absorbance at 330 and 281 nm, COD, and TOC from an actual PPMW containing 270 mg of C L -1 under natural pH (pH 11.25) using 2.1 g of H 2 O 2 L -1 at 28°C. Under these optimal conditions, pseudo-first-order kinetics was determined for absorbance at 330 and 281 nm and COD decay with rate constants of 0.029, 0.02, and 0.008 min -1 , respectively. Furthermore, the evolution with time of the H 2 O 2 concentration exhibits two parts: a linear decrease to 300 min and then exponential change until the end of the treatment. This shows that the kinetics of H 2 O 2 disappearance changes during the treatment from a pseudo-zeroth-order reaction in the first steps to a pseudo-first-order reaction in the final steps. On the other hand, a continuous decrease of pH and a rapid total phenols disappearance were observed during UV/H 2 O 2 treatment of PPMW. These results suggest that several steps are involved in the photochemical oxidation of organics, starting with degradation of lignin derivatives and tannins to obtain aromatic intermediates that then undergo oxidative ring opening, leading to aliphatic carboxylic acids. In the final steps, carboxylic acids are mineralized into CO 2 and H 2 O.
Chemical Engineering Journal, 2011
The aim of the study was to develop the mechanistic model describing the behavior of photo-Fenton process treating the simulated industrial wastewater containing oxalates and formates. In Part I of the study, the optimal conditions for each of applied photo-Fenton processes (UV-C/Fe/H 2 O 2 and UV-A/Fe/H 2 O 2) were determined and used in this study for model development and verification. The mechanistic model simulates the influence of various factors: the type of UV irradiation, the changes in concentrations of pollutants, catalysts and oxidant, on photo-Fenton process performance. pH dependent equilibrium of ferrous, ferric, oxalate and formate species was simulated as well. The model was tested to evaluate its accuracy in predicting the system behavior at different pollutant concentrations. Good agreement of the data predicted by model and the empirically obtained values was confirmed by calculated standard deviation for each experimentally monitored parameter. The developed mechanistic model describing the behavior of photo-Fenton process treating simulated wastewater can be characterized as interpretable, transparent, flexible and accurate. The comparison of electrical energy costs for each of the studied processes was performed. The obtained results indicate that the process using UV-C source is more efficient and cheaper. However, the simulation of process effectiveness using the solar UV-A irradiation recorded at annual basis for the location of proposed wastewater treatment plant speaks in the favor of solar UV-A/Fe/H 2 O 2 process application instead of artificial UV irradiation.
Solar photo-Fenton treatment—Process parameters and process control
Applied Catalysis B-environmental, 2006
Photo-Fenton experiments were performed using alachlor as a model compound (initial concentration 100 mg/L) in a compound parabolic collector solar pilot-plant. Three process parameters were varied following a central composite design without star points (temperature 20-50 8C, iron concentration 2-20 mg/L, illuminated volume 11.9-59.5% of total). Under all experimental conditions, complete alachlor degradation, mineralisation of chloride and 85-95% mineralisation of dissolved organic carbon (DOC) was achieved. An increase in temperature, iron concentration and illuminated volume from minimum to maximum value reduced the time required for 80% degradation of initial DOC by approximate factors of 5, 6 and 2, respectively. When process parameter changes were made simultaneously, these factors multiplied each other, resulting in degradation times between 20 and 1250 min.