Photocatalytic Wastewater Treatment Research Articles

Solar photocatalytic treatment of synthetic municipal wastewater

The photocatalytic organic content reduction of a selected synthetic municipal wastewater by the use of heterogeneous and homogeneous photocatalytic methods under solar irradiation has been studied at a pilot-plant scale at the Plataforma Solar de Almeria. In the case of heterogeneous photocatalysis the effect of catalysts and oxidants concentration on the decomposition degree of the wastewater was examined. By an accumulation energy of 50 kJ L −1 the synergetic effect of 0.2 g L −1 TiO 2 P-25 with hydrogen peroxide (H 2O 2) and Na 2S 2O 8 leads to a 55% and 73% reduction of the initial organic carbon content, respectively. The photo-fenton process appears to be more efficient for this type of wastewater in comparison to the TiO 2/oxidant system. An accumulation energy of 20 kJ L −1 leads to 80% reduction of the organic content. The presence of oxalate in the Fe 3+/H 2O 2 system leads to an additional improvement of the photocatalytic efficiency.

Photocatalytic Treatment of Cibacron Brilliant Yellow 3G-P (Reactive Yellow 2 Textile Dye)

The photocatalytic treatment of a textile dye wastewater, cibacron brilliant yellow 3G-P (reactive yellow 2), under the presence of UV-A radiation was studied. Treatment of test solutions containing 100 mg/L cibacron brilliant yellow dye with two types of photocatalysts, Degussa P25 and Hombikat UV 100 titanium dioxide, were investigated. The efficiency of these two commercial photocatalysts was compared in the presence and absence of hydrogen peroxide (H2O2). H2O2 concentration of 15 mM showed the best efficiency toward the photocatalytic treatment of the textile dye at the concentrations tested. Both decolorization and mineralization were significantly improved by using 15 mM H2O2. The treatment efficiency of the photocatalytic degradation of reactive yellow 2 was determined in terms of both adsorption kinetics and total mineralization. The decolorization and mineralization followed first order kinetics with a rate constant of 0.09 min−1 for decolorization with Degussa P25 titanium dioxide in the presence of H2O2. 71.3% chloride and 27.9% sulphate were yielded after complete decolorization in the photocatalytic treatment of the dye. However, only 0.78% yield of the nitrate was obtained by photocatalysis. The formation of intermediates was not significant compared to the original dye solution in terms of absorbance.

Photocatalytic Wastewater Treatment for 4-Nonylphenol of an Endocrine Disruptor and 4-Nonylphenol polyethoxylate Surfactant at the Titania/Water Interface

The biodegradation of 4-nonylphenol polyethoxylate (NPE-n) nonionic surfactant through bacteria results in the formation of toxic 4-nonylphenol (NP) that has been identified as an endocrine disruptor by EPA. NP persists in nature for long periods, and consequently, new wastewater treatment should be established to ensure aquatic environmental protection.The photodegradation of NPE-n, NP and mixture solutions at the TiO2/water interface was investigated. The photodecomposition of NP solution and NP/NPE-n mixed solutions (each 0.1mM) in aqueous TiO2 (100mg) suspensions under UV-irradiation (320nm<λ<387nm) was monitored. After filtering TiO2 particles, photodegradation kinetics were examined by surface tension, UV-absorbance, CO2 evolution, TOC, FT-IR, 1H-NMR and GC-MS. The aggregation of TiO2 particles (studied by dynamic light scattering) and the formation of carboxylic acid intermediates (with HPLC) were examined. Surface photocatalytic reactions of NPE-n and/or NP structures on the TiO2 semiconductor were studied by molecular orbital (MO) simulation. Efficient adsorption of the ethoxyl group on the TiO2 surface was initially noted, followed by cleavage of the aromatic ring and the ethoxyl moiety by direct photooxidation and attack of OH radicals. No NP formation was detected in the photodecomposition of NPE. The photomineralization of the ethoxyl moiety proceeded via formic acid, and other alkyl groups and benzene rings were converted to acetic acids. The photooxidation of hydrophobic NP material proceeded as follows : (i) adsorption of the OH moiety in NP on the TiO2 surface, (ii) facile ring-opening cleavage of phenol and (iii) CO2 gas evolution for mineralization of NP. The photooxidation of mixed NPE-n and NP solution could be predicted from TiO2 photooxidation results with pure NPE-n and/or NP solutions, photocatalytic degradation is thus shown to be a promising route for wastewater treatment of surfactants.

Photocatalytic Treatment of an Industrial Wastewater in the Double-Skin Sheet Reactor

The cleanup of polluted industrial wastewater with the aim of reusing it in the production is state-of-the-art technology. From an economic point of view, interest attaches to chemical oxidation processes operating at ambient temperature, employing molecular oxygen dissolved in the wastewater as the only oxidant, and utilizing solar irradiation as the necessary activation energy. Presently, photocatalysis is the only technique meeting all these requirements. The photocatalytic degradation of organic pollutants present in biologically pretreated industrial wastewater samples was investigated in a recently introduced double-skin sheet reactor using artificial as well as solar light. A significant decrease of the pollution by organic compounds was observed.

Photocatalytic Treatment of Wastewater From 5–Fluorouracil Manufacturing

This paper presents some of the experimental results from a study conducted to demonstrate the potential use of photocatalytic oxidation for decolorization and COD reduction of wastewater from 5–fluorouracil manufacturing. A series of batch experiments, were carried out using diluted solutions of the wastewater with 0.1 percent w/v TiO2. Low pressure mercury lamps were used to simulate the UV part of sunlight. The experiments showed that a complete decolorization and a substantial reduction of COD was achieved within 20 hours with a 20 percent solution. During the reaction period, the pH was noted to decrease considerably, indicating formation of acids. Adding hydrogen peroxide to the solution was found to significantly increase the reaction rates. Adding 2400 ppm of H2O2 gave an 80 percent decrease in color in one hour and a 70-80 percent decrease in COD in 20 hours. The influence of UV-light intensity was also examined. This experiment showed that with a UV-intensity of 15 W/m2, i.e., a cloudy day, the decolorization rate was still considerable, while the COD reduction rate was very low.

New Reactor Design for Photocatalytic Wastewater Treatment with TiO2 Immobilized on Fused-Silica Glass Fibers: Photomineralization of 4-Chlorophenol

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNew Reactor Design for Photocatalytic Wastewater Treatment with TiO2 Immobilized on Fused-Silica Glass Fibers: Photomineralization of 4-ChlorophenolK. Hofstadler, Rupert. Bauer, S. Novalic, and G. HeislerCite this: Environ. Sci. Technol. 1994, 28, 4, 670–674Publication Date (Print):April 1, 1994Publication History Published online1 May 2002Published inissue 1 April 1994https://doi.org/10.1021/es00053a021RIGHTS & PERMISSIONSArticle Views2026Altmetric-Citations222LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Photocatalytic wastewater treatment combined with ozone pretreatment

Photocatalytic wastewater treatment combined with ozone pretreatment