Photocatalytic Degradation of Organics in Municipal Treated Wastewater in a Re-Circulation Reactor (original) (raw)
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International Journal Of …, 2011
During the last few years, there has been a plethora of research and development in the area of solar photocatalysis. The aim is to understand the fundamental processes and enhance photocatalytic efficiencies especially for air, soil and water pollution control. Municipal waste water is limited by continual organic water pollutants and micro-organisms that are not removed by conventional mechanical and biological treatment. In this overview of the most recent paper, studies focused on the treatment of municipal wastewater (containing organic compounds) by photocatalysis and the effects of various parameters such as pH, light intensity, Advance oxidation method etc. have been studied It can be concluded that the photocatalysis process is suitable for the treatment of drinking water, municipal and industrial wastewater. Some studies on the economic analysis of photocatalytic systems are also included.
International Journal of Chemical Reactor Engineering, 2014
In this study, a highly polluted wastewater from tannery industry is treated by photocatalysis using home-made N-doped TiO2 as catalyst. The doping by nitrogen of titania particles leads to a reduction in the absorption threshold from 3.2 to 2.5 eV, permitting the absorption of radiation characterized by a wavelength in the visible spectrum.Experiments were carried out by using different light sources, in particular white LEDs, blue LEDs, and UV lamps, with the aim to evaluate the process efficiency at different operating conditions. The obtained performances were compared with those using an undoped commercial TiO2 catalyst (Degussa P25).Moreover, a simplified mathematical model capable to correlate the power input of the used light sources, the geometrical properties of the reactor, and emitting sources spectra with the performances of the photocatalytic reaction was developed.
Detoxification of Industrial Waste Water By Photo Catalyst Process Using Parabolic Collector
The generation of hazardous industrial effluents is a serious problem experienced by both the developed and developing world. There are several methods by which water can be purified to different specifications. Some of the unit operations may be carbon adsorption, electro-dialysis, filtration, ionexchange, reverse osmosis, sterilization, and photo-oxidation. Traditional waste treatment systems use the techniques such as coagulation, chlorination or ozonation which utilise potentially hazardous or polluting materials. But now-a-days, most of the research is carried out on photocatalyst process using Titanium dioxide (TiO 2 )as catalyst and ultra-violet radiation of solar spectrum to detoxify the industrial waste water. In this paper, waste water which contains the milk contaminants is detoxified by using the compound parabolic collector of concentration ratio of 1.15. Experimental results present the effect of solar radiation and time on the dissolved oxygen and system efficiency.
Applied Catalysis B: Environmental, 2011
This article reports on degradation using TiO 2 immobilized on glass spheres of 15 emerging contaminants (ECs) at low concentrations in simulated and real Municipal Wastewater Treatment Plant (MWTP) effluents. A sol containing titanium isopropoxide, commercial P25 and polyethylene glycol (PEG) was prepared, and a layer of the photoactive precursor was immobilized on glass spheres by dip-coating. The raw materials and the xerogels were characterized by N 2 adsorption/desorption, XRD and TGA-DTA. The xerogel showed the TiO 2 anatase, rutile and brookite crystal phases characteristic of the reference materials. The diffraction pattern showed no modification of the crystal size from incorporation of the PEG. Two different TiO 2 anatase crystal sizes were identified, which was attributed to the different TiO 2 precursors used in the synthesis route. Degradation of the emerging contaminants (acetaminophen, antipyrine, atrazine, carbamazepine, diclofenac, flumequine, hydroxybiphenyl, ibuprofen, isoproturon, ketorolac, ofloxacin, progesterone, sulfamethoxazole and triclosan), at an initial concentration of 100 g L −1 each was determined by ultra-performance liquid chromatography (UPLC-UV) and mineralization was monitored by measuring the dissolved organic carbon (DOC). The experiments were performed in a pilot compound parabolic collector (CPC) solar plant at the Plataforma Solar of Almeria (Spain). 85% of the compounds were degraded within 120 min of illumination time depending on the water. The results show the potential application of this technology as a good alternative to suspension systems for the treatment of polluted water.
Solar Photocatalytic Treatment of Sewage using Titanium Dioxide
Pure water is never found in nature and it is increasingly rare to encounter a source of water that requires no treatment before being used for portable water supply. Conventional treatment methods are not effective for the degradation of toxic organic pollutants; hence other treatment techniques are necessary. One of the recent developments in this field is the Advanced Oxidation Process (AOP). In this Advanced Oxidation Process, photo catalysis is a technique which utilizes the solar radiation to treat the sewage with more organic contents. For the removal of organic waste form the sewage, oxidation reduction reaction is used and this reaction is accelerated using titanium dioxide as a strong oxidizing agent. Titanium dioxide (TiO2) is widely used as a catalyst for this purpose, to oxidise or reduce the organic pollutants in wastewater. This paper deals with performance of the titanium dioxide under varying parameters of the sewage and its efficiency. The photo catalysis of sewage has been studied for removal COD reduction. The influence of TiO2 catalyst on COD removal efficiency was recorded. Maximum COD removal of the sewage achieved was 95% after catalyst dosage of 20 g/500ml at alkaline pH 7.6 and at 33 o C temperature. Effective contact time is 50 minutes with optimum catalyst and pH. The photocatalytic degradation process using TiO2 as an irradiation source showed potential application for the COD removal of the sewage.
International Journal of Hydrology Science and Technology, 2018
The use of TiO 2 as a solar photocatalytic oxidant to treat real wastewater effluent from a decentralised unit was investigated. Potassium hydrogen phthalate (KHP) is used here as a standard for both chemical oxygen demand (COD) and total organic carbon (TOC). The catalyst load, initial KHP concentration and pH are the variables studied in this research. The optimum flow rate is 2.5 L/min in the tubular reactor. The removal efficiency of the organic compounds reduces as the initial concentration of KHP increases. The photocatalytic oxidation is dependent on pH and, it increases with the increasing of pH, the results show that a complete oxidation of KHP occurs at pH 9. Treatment of secondary treated wastewater results in about 50% for COD reduction which could attribute to the removal of organic matter and 100% inactivation of E. coli with no regrowth after 24 h storage in dark was obtained.
Water samples from two types of sources: partially treated sewage generated by a medium-sized city, with a high quantity of total coliforms and partially treated industrial wastewater, which contained mostly petroleum products from refineries, were treated using the same concentration of TiO 2 catalyst, for different exposure periods. UV-Vis and fluorescence spectroscopic evaluation of the composition changes of wastewaters under non selective oxidation conditions (achieved by photocatalysis) revealed that the higher removal rate was obtained for the industrial water sample compared to the sewage water sample, with respect to oxidation time. Considering the diverse characteristics and the solution matrix effects of the wastewaters, UV-Vis and fluorescence spectra revealed different patterns by increasing the quantity of TiO 2 catalyst from 0.25 mg mL-1 to 1 mg mL-1 , denoting that the amount of total coliforms in a sample greatly impacts the degree of photocatalytic oxidation.
Photocatalytic Degradation of a Chemical Industry Wastewater: Search for Higher Efficiency
2017
15 Páginas, 8 Figuras, 3 TablasIn the present research, an annular photocatalytic reactor system was designed and operated to quantify the degradation of a real case chemical company wastewater. The photocatalytic degradation process was analyzed and optimized varying some critical operating variables such as pH, catalyst (TiO2) loading, H2O2 concentration (oxidant agent) and light intensity to find the best criterion warranting a high level of degradation. It was demonstrated that a pH of 7.0 and an amount of 2.0 g/L ofTiO2 resulted in a cleanup allowable level for discharge to river. Furthermore, photo-degradation by H2O2/TiO2/UV process was much more efficient (97%) with respect to the processes carried out individually by H2O2/UV(92%) orTiO2/UV (89%). It is remarkable that the optimum concentration of H2O2 was 11.6mM, and increasing the intensity of light accelerated degradation reaction. Careful selection of industrial wastewater reflected the capability predicting the level of...
Novel Solar Photocatalytic Reactor for Wastewater Treatment
IOP Conference Series: Materials Science and Engineering, 2017
A new solar photocatalytic reactor (photoreactor) using TiO2 nanoparticles coated onto plastic granules has been designed. Catalyst granules are placed into the cavity of a reactor panel made of glass. A pump is used to circulate wastewater in the photoreactor. Methylene blue (MB) dissolved in water was chosen as the wastewater model. The performance of the photoreactor was evaluated based on changes in MB concentration with respect to time. The photoreactor showed a good performance by degrading 10 L of MB solution up to 96.54% after 48 h of solar irradiation. The photoreactor was scaled up by enlarging the panel area to twice its original size. The increase in the surface area of the reactor panel and therefore of the mass of catalyst granules and reactor volume led to a three-fold increase of the photodegradation rate. In addition, the MB degradation kinetics were also studied. Data analysis confirmed the applicability of the pseudo-first-order Langmuir-Hinshelwood model. The proposed photoreactor has great potential for use in large-scale wastewater treatment.