1,720,992 research outputs found
Heterogeneous Photo-Fenton Degradation of Dye RB5 using Fly Ash and Foundry Sand as Iron Source
No full textMT, SEEThis work evaluates the scope of alternative sources of iron i.e. Foundry Sand (FS), Fly Ash (FA) and mixture of FS and FA in heterogeneous photo-Fenton process for the degradation and decolorization of the dye Reactive Black5 (RB5). The aim was to see the best effect of alternative iron source i.e. FS and fly ash in terms of degradation and decolorization efficiency. EDS characterization of FS and FAconfirmed the presence of iron and aluminium which are required for photo-Fenton. A comparative assessment was attempted after initial optimization studies, viz., varying H2O2 concentration, pH, initial dye concentration, and iron (FS/Fly Ash/FS+Fly Ash) concentration. In case of FS as an iron source, results showed that the degradation and decolorization efficiency i.e. 90% was achieved in 70 min and 45 min respectively when the reaction parameters were H2O2= 2.2 mM, FS dose= 0.5 g, pH 3, initial dye concentration= 100 mgL-1. While having fly ash as an iron source 90% degradation within 30 min and 93% decolorization rates within 15 min were achieved under optimum conditions i.e., H2O2= 2.2 mM, Fly ash dose= 0.1 g, pH 3, initial dye concentration= 100 mgL-1. When a mixture of FS(0.1 g) and Fly Ash(0.05 g) is used as source of iron 99% degradation and decolorization of the dye was achieved under the reaction conditions where H2O2= 2.2 mM, Ash:Sand= 1:2, pH 3, initial dye concentration= 100 mgL-1. Thus, it is a viable option to use a mixture of FS and fly ash to have a better effect on degradation and decolorization taking advantage of the individual performanceSchool of Energy and Environmen
Degradation studies of reactive black 5 and textile industry wastewater by combined photo-fenton and biological oxidation
No full textM.Tech (EST) DissertationIn the present study, the photo-Fenton process was used for the pretreatment of Reactive Black 5 dye and industrial textile wastewater with the objective of improving its overall biodegradability and determining the degree of increased oxidation followed by biological process. Some parameters, like pH, temperature, initial concentrations of Fe2+ and H2O2 and the use of natural or artificial light were evaluated aiming to find the optimal conditions to promote the efficient degradation of the dyes. The experimental results showed that the photo-Fenton process run under solar light was the most effective. The degradation observed is 91% with optimal conditions of pH=4, H2O2=4.4 mM and Fe2+ =0.15 Mm with 90 mins Process under UV light alone for photo-Fenton process. The optimal time to stop the pretreatment process and introduce the effluent to the biological system was 20 min. The biodegradability of the process was checked by BOD5/COD ratio. Results obtained from this work indicated that the photo-Fenton process could be a suitable pretreatment method in reducing toxicity of pollutants and enhancing biodegradability of textile wastewaters treated in a coupled photochemical–biological system.School of Energy and Environment, Thapar University, Patial
Degradation and decoloursation studies of paper mill effluents by TiO2 photocatalysis
No full textM.Tech (EST) DissertationThe paper industry has historically been one of the world’s largest consumers of freshwater resources and producers of wastewater discharges. The effluent contains a number of toxic organic compounds that may cause devastating environmental impacts to receiving waters when discharged directly. The scope of this project is to see photocatalysis as a viable treatment option in degrading and mineralizing the recalcitrant organic compounds as well as the possibility of utilizing the solar light spectrum.
The experiments and analysis work is done on actual industrial wastewater. The process optimization like pH, catalyst concentration, oxidant dose, light intensity is carried out to obtain the best result for complete transformation of the toxic organic compounds to benign chemicals. The COD reduction of bleaching effluent observed was 86% and 91% under UV and solar light, respectively (with optimized conditions i.e. 7.5 pH, catalyst concentration of 0.5 gL-1 and oxidant dose (H2O2) of 2 ml L-1) after 3 hrs of treatment. The biodegradability (BOD5/COD) of the effluents is improved proposing AOP efficiency as pre-treatment option before biological treatment. Efforts have also been done on the application of AOP for the pre/post-treatment of RO reject water to make it fit for reuse/dilutions in industries. The present study also investigates the efficiency of AOP on color remediation of final ETP effluent. The results of photocatalytic degradation showed that it could be used as pre or post treatment technique for the complete degradation of recalcitrant organic pollutants present in paper mill effluent.School of Energy and Environment, Thapar University, Patial
Degradation Studies of Insecticide Imidacloprid Using Fluidized Bed Photocatalytic Reactor
No full textMaster of Technology DissertationDisposal and treatment of wastewater containing bio-recalcitrant such as insecticide imidacloprid is a matter of great concern. Various conventional and existing treatment technologies could only concentrate the pollutants by transferring them from one phase to the other. Moreover, the conventional treatments could also generate toxic secondary pollutants too, which further adds up the operational costs. Hence there is an urgent need to look for the advanced and emerging technologies which could completely mineralize the irrespective pollutants. Advanced Oxidation Process has emerged one such technology for treatment of such bio-recalcitrant compounds, which relies on the principle of production of high oxidation potential hydroxyl ions which ultimately converts the toxic compounds to non-toxic end products.
One such approach in AOP‟s include Fixed Bed Photocatalysis to treat pesticidal wastewater using suitable catalyst such as TiO2 P-25 Degussa. Since the mode of catalyst usage and its recovery is a matter of concern from the economical point of view, hence the immobilization of catalyst onto suitable support material is the need of hour. Pebbles made out of cement and sand mixture proved to be mechanically robust, chemically inert and cheap immobilizing material which has the very high adsorptive capacity towards the catalyst with negligible catalyst attrition rate. In the present study, 25 mg/L of pesticide imidacloprid solution was treated under optimized conditions and various parameters and degradation feasibilities were analyzed. Various diameters of immobilizing material were tried and the optimum results were found at 0.75 cm diameter along with catalyst loading of 3% (w/w), degradation was found out to be 81.1%. Effect of oxidant dose was also studied and the degradation occurred was as high as 88% under the optimum dosage of 4.8 ml/L.School of Energy and Environment, Thapar University, Patial
Fixed Bed Photocatalysis for the Degradation of 2-Chloro 4-Nitrophenol Using Solar Irradiation
No full textPhenol and phenolic compounds occur as waste from various industries like Oil refining, petrochemical, coal mining, lignite transformation etc. and result in bioaccumulation. Water from natural sources is mainly polluted due to chemicals present in the wastewater let out from industries of various domains. High COD, opacity, high alkalinity/acidity, high total solids and high BOD are the characteristic of industrial wastewater. This creates an imbalance in the ecosystem and hence treatment of such wastewaters is needed. 2 chloro 4 nitro phenol (2-C 4-NP) is one among the mostly used phenolic compound. It is used as an intermediate in wood preservative, in the medical treatment of obesity, and also in a pesticide. An effective and economic treatment for eliminating phenolics in water has been in urgent demand. One method to remove 2-C 4-NP from the wastewater is fixed bed photocatalysis.
Photocatalysis is a technique that uses solar radiation and a photocatalyst, the photon energy from sun is used for generating hydroxyl radicals formed as a result of oxidation of catalyst that remove organic matter in wastewater.
TiO2 is one of the most popular and promising materials, because of its stability under harsh conditions, commercial availability, different allotropic forms with high photo-activity, possibility of coating as a thin film on solid support, ease of preparation in the laboratory etc. Its absorption spectrum overlaps with the solar spectrum and hence opens up the possibility of using solar energy as the source of irradiation. To eliminate the need of filter during post-treatment removal using suspended photocatalyst, researchers tested various catalyst supports.
The scope of the study is to see the heterogeneous photocatalytic degradation of 2-C 4-NP in TiO2 fixed bed reactor. For the process optimization like pH, Oxidant dose, initial concentration suspension mode photocatalysis. For the immobilization of catalyst three different supports (cemented beads, glass sheet and sodium alginate balls) are used. The degradation studies in slurry form are investigated using TiO2 Degussa photocatalysts under UV illumination. The study includes dark adsorption, UV light treatment along with variation in different parameters like pH, amount of photocatalyst, effect of H2O2 concentration.
Degradation observed was 89%, 70%, 65% and 60% under suspension solar-photocatalytic, glass-plate solar reactor, coated cemented beads and immobilized sodium alginate ball; respectively at optimized conditions i.e. 4.5 pH, catalyst concentration of 1 g/l and oxidant dose of 7.5mM/200ml. The dip and coating method was used for the catalyst immobilization on the glass and cemented beads, whereas in other case, physical entrapment of the catalyst slurry in the gel was used. Approximately 95% reduction in COD confirms the mineralization of the compound under study.
Result shows that fixed bed photocatalysis would be more efficient and economical as filtering as well as recovery of the catalyst can be avoided. The application of solar powered photocatalytic reactors to treat waste water from different industries holds promise for regions receiving strong sunlight throughout the year, such as India
Potential Use of Foundry Sand as Heterogeneous Catalyst in Solar Photo-Fenton Degradation of Herbicide Isoproturon
No full textM.Tech.This study deals with employing foundry sand (FS) as new low cost iron source in heterogeneous photo-Fenton process for the degradation of herbicide isoproturon (IPU) in aqueous solution. The characterization of the FS by EDS confirmed presence of iron (23%) required for photo-Fenton and simultaneously confirmed absence of any heavy metals which may susceptible to leaching. The photo-Fenton effects of different reaction parameters like H2O2 concentration [H2O2]0, operating pH, initial concentration of IPU [C0], FS dose, recycling of FS, effect of area/volume ratio were investigated. Results showed that the maximal removal efficiency were achieved when reaction parameters was [H2O2]0= 2.2 mM, pH 3, FS dose=0.5 gL-1, [C0] =25 mgL-1. Under optimum condition, 97% degradation efficiency of IPU was achieved within 150 min of reaction. The catalyst recycling test was performed and FS was effectively recycled for 4 times with 20% reduction in degradation efficiency. SEM-EDS analysis of recycled FS confirmed morphology of FS unchanged. Solar baffled batch reactor (SBBR) with recirculation confirmed 70% degradation of IPU after 6 h
Sonophotocatalytic Degradation of Alizarin Red: Reactive Dye Over Slurry Titanium Dioxide
No full textThe release of dyes into the receiving water bodies is deleterious, not only because of
their color, but also because they are not easily degraded by aerobic bacteria and forms
toxic compounds under the action of anaerobic bacteria. Therefore, it becomes imperative to completely degrade these organic compounds before their discharge. Such pollutants cannot be completely degraded by well established techniques like coagulation, flocculation, precipitation, adsorption, membrane separation, aerobic biological treatment. The incapability of conventional wastewater treatment methods to effectively remove such pollutants leads to explore the new, efficient and cost effective treatment systems. In order to meet stringent environmental regulations, the latest development is the oxidation of these biorecalcitrant organic compounds. These radicals have high oxidizing power superior to other usual oxidants and results in complete degradation. The methods are called advanced oxidation processes (AOP’s),which are characterized by
production of the hydroxyl radical (OH) as a primary oxidant. Examples of AOP’s include the use of (H2O2/UV), semiconductor photocatalysis, ozonolysis and ultrasonic
irradiation (sonolysis), (ultrasound/O3) as important segmental or parallel processes and
are found to enhance OH radical production leading to higher oxidation rates and organic
matter mineralization. In this work, we investigated the Photocatalytic oxidative
degradation and discoloration of various reactive dyes and dye intermediates using light (UV/visible)/semiconductor catalyst by optimizing the operational parameters to ensure the rapid and complete transformation of the toxic organic compounds to benign
chemicals. Also the simultaneous sonochemical effect along with photochemical
oxidation process light/semiconductor/ultrasound) is used which leads to faster destruction rate.
The scope of this project is to see Sonophotocatalysis as a viable treatment option in case of dyes. Titanium dioxide was used as Photocatalyst. Experiments were
performed in slurry mode in both UV and solar light at optimized condition. The
degradation of wastewater has been investigated in terms of reduction in Conc. Various process parameters like catalyst dose, pH, concentration of oxidant, initially pollutant concentration were varied and their effects have been analyzed. In this case the catalyst concentration was optimized at .1g/200ml, pH at 4.8 and oxidant concentration at 3ml/200ml of the sample. The results obtained were quit appreciable as it reduced COD from 240 to 80 mg/l, BOD from 80% mg/l.
The results of Sonophotocatalytic degradation of dyes showed that it could be used as efficient and environmental friendly technique for the complete degradation of
recalcitrant organic pollutants which will increase the chances for the reuse of
wastewater. The investigations demonstrate the importance of selecting the optimal
degradation parameters for practical applications of this operation
Decomposition of Commercial Available Monocrotophos in Aqeous Solution of tio2 by Sonophotocatalysis
No full textEnvironmental Protection Agency (E.P.A.,1990) estimates aboutmore than 600 million pounds of pesticides enter the environment each year in the environment. Pesticides are included in a broad range of organic micro pollutants that have ecological impacts. Different categories of pesticides have different types of effects on living organisms and these different type of pesticides has a property of bioaccumulation in the environment. Mainly pesticides are not completely degraded during conventional treatment technology due to low biodegradability. Field surveys shows that due to not complete mineralization, some amount of pesticides are released in aquatic environment and mix into ground water and used as a source of drinking water. So there is a clear need to set up the emerging alternative technologies that can deal with highly concentrated and toxic nonbiodegradable pesticides.
So recently considerable interest has been shown by researchers towards the degradation of pesticides by advanced oxidation process such as photocatalysis, sonolysis, sonophotocatalysis,. These technique are basically very ecofriendly and time consuming technology and most basic advantage of these technology is completely destruction of any toxic compounds into nontoxic ending products and it can be easily carried out at room temperature and atmospheric pressure.
Basic principle behind of these technology is production of OHº radical which has high oxidation potential and mainly its nonselective property. These OHº radical can easily react with the toxic compound due to its high potential capability and change into nontoxic ending products.
Photocatalysis itself is a very advance technique which has large potential for the degradation of any complex organic matter. But if the two modes of irradiations (photocatalysis and sonolysis) are used in combination, degradation would be enhance because sonolysis process improve the mass transfer and surface area.
In this present work, we are investigating the sonophotocatalytic degradation of commercially used pesticide Monocrotophos. Titanium dioxide (TiO2) was used as Photocatalyst. Experiments were performed in slurry mode in UV light and at optimized condition. The process is optimized by varying different parameters like catalyst concentration, operating pH, H2O2 conc., Initial pollutant conc. in photocatalytic experiment
In photocatalytic experiment, 92% degradation was found under the optimized catalyst concentration of 1gL-1, pH 4 and oxidant concentration of 0.375mgL-1 within 2 hoursand 80% mineralization was achieved in 6 hours.
In sonophotocatalytic experiment, 97 % degradation was found under same optimized condition after running of 2 hours and 88% mineralization was achieved in 6 hours.
Positive result of the synergy effect shows that combined effect has more valuable in comparison of both individuals treatment. So the results of Sonophotocatalytic degradation of monocrotophos compound showed that it could be used as efficient and environmental friendly technique for the complete degradation of recalcitrant organic pollutant
Degradation studies of paracetamol using novel Fe-TiO2 composite
No full textA novel composite Fe-TiO2 was made by mixing fly ash (FA), foundry sand (FS), and, Bentonite
clay in required amounts. This composite acts a surface for immobilizing the TiO2 (using dipcoating method) besides facilitates leaching of iron (FA and FS). leached iron promotes the
photo-Fenton (with the presence of H2O2 in the system) while surface active TiO2 layer lead to
photocatalysis. Degradation of paracetamol was acquired by dual process combining
photocatalysis and photo-Fenton happening at same place and same time. This dual process
showed best results of 96.6% degradation at optimized conditions i.e. H2O2 dose (525mg/L),
number of beads (80), degradation time (215 minutes), volume (200 mL). The enhancement of
degradation and decrease in degradation time over first order rate constant (k) was achieved. To
be sure, even a couple of overlay augments in 'k' value was seen by using novel Fe-TiO2
composite for the paracetamol degradation confirming in-situ impact. The stability of catalyst
was confirmed by several characterizations like XRD and SEM/EDAX. Moreover mineralization
of paracetamol included nitrate, nitrite, total iron estimation, and products formed during
degradation were confirmed by GC-MS analysis
Environmental Impact Assessment in a Secondary Metallurgical Industry With Respect to Air Pollution
No full textM Tech Thesis (Environmental Science and Technology)In this project work the environment impact assessment of a secondary metallurgical industry
situated near mandi gobindgarh town is studied primarily focusing on ambient air pollution. First
of all the sites are selected for the monitoring purpose on the bases of guidelines, obtained
meteorological data and our requirement. Sampling for the pollutants is done and then is
compared with the standards. Further the ground level concentration of the pollutant is obtained
using the AERMOD view cloud software which is based on the Gaussian model. A certain site
was elected for the study of project. The selected site is a secondary metallurgical industry which
does fall under the A category as it is situated in the mandi gobindgarh which is categorized as
highly polluted area by CPCB. This project work includes the Collection and interpretation of
the Meteorological data ,Collection of Ambient air quality data, Analysis of Ambient air quality
data and its interpretation, Evaluation of ground level concentration of pollutants due to stack
emission, Analysis of results obtained and its comparison with results from other sources
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