scholarly journals Photocatalytic disinfection of water polluted by Pseudomonas Aeruginosa

2013 ◽  
Vol 9 (2) ◽  
pp. 132-136
Keyword(s):  
Cell Wall ◽  
Ascorbic Acid ◽  
Removal Efficiency ◽  
Uv Irradiation ◽  
Photocatalytic Oxidation ◽  
Irradiation Time ◽  
Cell Mass ◽  
Treatment Method ◽  
Inhibitory Effect ◽  
Intact Cells

Photocatalysis by titanium dioxide (TiO2) is a water treatment method. Pseudomonas aeruginosa is a microorganism resistant to chlorine and UV-C irradiation. TiO2 photocatalytic technology can destroy bacteria, which are resistant to oxidative destruction of cell membrane caused by sole UV irradiation. This study aims to investigate the total mineralization of the bacterium (P. aeruginosa) to the extent of death and cell-mass destruction using TiO2 photocatalytic oxidation process. In this work the effects of parameters such as amount of TiO2, irradiation time, initial concentration of bacterium, presence of ascorbic acid and effect of cell wall on removal of P. aeruginosa were studied. The data, which were obtained in this study, showed that the optimum concentration of TiO2 was 325 ppm. Also at the initial concentration of TiO2 equal to 325 ppm and initial microorganism MPN / 100 ml equal to 300 and after 75 min UV irradiation time, P. aeruginosa removal efficiency was 94.3 %. Removal efficiency of P. aeruginosa in the absence of TiO2 or UV irradiation was very low. Decreasing the concentration of microorganisms increased its removal efficiency. Removal efficiency of spheroplast cells was more than intact cells of P. aeruginosa, which shows the important role of cell wall on cell resistance against chemical agents. Ascorbic acid had inhibitory effect on this process.

scholarly journals Study of C.I. Acid Orange 7 removal in contaminated water by photo oxidation processes

2013 ◽  
Vol 10 (1) ◽  
pp. 16-23 ◽  
Keyword(s):  
Removal Efficiency ◽  
Uv Irradiation ◽  
Rate Constant ◽  
Dye Removal ◽  
Irradiation Time ◽  
Inhibitory Effect ◽  
Textile Dye ◽  
Acid Orange 7 ◽  
Acid Orange ◽  
First Order

C.I. Acid Orange 7 (AO7) commonly used as a textile dye and could be degraded by UV/ZnO, UV/H2O2 and UV/H2O2/Fe (III) (photofenton) processes. In the photocatalytic degradation of dye by UV/ZnO process, effect of some parameters such as UV irradiation time, presence of ZnO and UV irradiation, pH, concentrations of ZnO, dye, H2O2 and ethanol was examined and first order reaction rate constant was calculated equal to 2.39×10-2 min-1 at experimental condition. The semi-log plot of dye concentration versus time was linear, suggesting first order reaction. Efficiency of photodegradation process in the absence of ZnO photocatalyst and UV light was small. Increasing the UV irradiation time increased AO7 removal. Ethanol had inhibitory effect on this process. Maximum AO7 removal was seen at neutral pH area. In the UV/H2O2 process, effect of some parameters such as presence of H2O2 and UV irradiation, amount of H2O2, effect of pH and addition of bicarbonate on the efficiency of dye removal were examined. Absence of each of UV irradiation or H2O2 decreased AO7 removal efficiency near to zero. Increasing H2O2 concentration increased dye removal to some extent but at higher H2O2 concentrations, dye removal efficiency did not increase. Increasing pH to value about 9 increased the AO7 removal efficiency and increasing bicarbonate anion concentration decreased it. Rate constant of AO7 removal by this process was calculated to be equal to 4.221×10-1 min-1 at experimental condition. Also, the order of UV/ H2O2/Fe (III) > UV/ H2O2 > UV/Fe (III) > H2O2/Fe (III), was seen for AO7 removal efficiency of these processes. Increasing Fe (III) and oxalate concentration increased dye removal efficiency.

scholarly journals Factors Determining the Removal Efficiency of Procion MX in Waters Using Titanate Nanotubes Catalyzed by UV Irradiation

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Vo Nguyen Xuan Que ◽  
Tran Tien Khoi ◽  
Nguyen Thi Thuy ◽  
Ta Thi Minh Dung ◽  
Dao Thi Thanh Binh ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Uv Irradiation ◽  
Textile Industry ◽  
Photocatalytic Oxidation ◽  
Organic Dyes ◽  
Treatment Method ◽  
Titanate Nanotubes ◽  
Efficient Treatment ◽  
Ph Variation ◽  
Set Up

The treatment of wastewater from the textile industry containing organic dyes faces many challenges since these compounds resist the biodegradation process in conventional treatment units. Among the physicochemical processes, photocatalysis is considered a facile, cheap, and environmental-friendly technology for treating persistent organic pollutants in waters at low concentrations. This study investigated several physicochemical factors determining the photocatalytic activity of titanate nanotubes (TNTs) to remove Procion MX 032 (PMX), an azo dye, in waters. Degradation of PMX by photocatalytic oxidation process at room temperature (30°C) was set up with the UV irradiation in the presence of different types of photocatalyst such as ST-01 (100% anatase), industrial TiO2, TNTs calcined at 120°C and 500°C. Effect of reaction time, catalyst amount, pH, light wavelength and intensity, and oxidants was investigated. Consequently, TNTs calcined at 500°C provided the highest removal efficiency. The photocatalytic oxidation of PMX by TNT calcined at 500°C was affected by pH variation, getting the highest removal at pH of 8, and inhibited with the presence of H2O2 and O2. Particularly, the PMX degradation using titanate nanotubes was optimized under the UV-A intensity of 100 W/m2. The dye was degraded by more than 95% at the TNTs concentration of 75 mg/L and pH 8.0 after 90 min. The results suggest that photocatalysis using TNTs can be a simple but efficient treatment method to remove PMX and potentially be applied for the treatment of wastewaters containing dyes.

scholarly journals Mechanistic studies on the biosorption of Pb(II) by Pseudomonas aeruginosa

2018 ◽  
Vol 78 (2) ◽  
pp. 290-300
Author(s):  
S. Vimalnath ◽  
H. Ravishankar ◽  
C. Schwandt ◽  
R. V. Kumar ◽  
S. Subramanian
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Treatment Method ◽  
Enzymatic Treatment ◽  
Intact Cells ◽  
Cell Wall Components ◽  
Before And After ◽  
Pseudo Second Order ◽  
Wall Components

Abstract The biosorption of Pb(II) ions from aqueous solution has been studied using both the intact and thermolyzed cells of Pseudomonas aeruginosa. Further, the role of the major cell wall components, namely DNA, protein, polysaccharide, and lipid, in Pb(II) binding has been assessed using an enzymatic treatment method. The Pb(II) bioremediation capability of P. aeruginosa cells has been investigated by varying the parameters of pH, time of interaction, amount of biomass, and concentration of Pb(II). The complete bioremoval of Pb(II) using intact cells has been achieved for an initial Pb(II) concentration of 12.4 mg L−1 at pH 6.2 and temperature 29 ± 1 °C. The biosorption isotherm follows Langmuirian behavior with a Gibbs free energy of −30.7 kJ mol−1, indicative of chemisorption. The biosorption kinetics is consistent with a pseudo-second-order model. The possible Pb(II) binding mechanisms of P. aeruginosa cells are discussed based on characterization using zeta potential measurements, Fourier transform infra-red spectroscopy, and energy dispersive X-ray spectroscopy. The results confirm that among the major cell wall components studied, polysaccharide shows the highest contribution towards Pb(II) binding, followed by DNA, lipid, and protein. Similar studies using thermolyzed cells show higher Pb(II) uptake compared to the intact cells both before and after enzymatic treatment.

scholarly journals Photocatalytic Oxidation of Gaseous Benzene under 185 nm UV Irradiation

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Haibao Huang ◽  
Xinguo Ye ◽  
Huiling Huang ◽  
Peng Hu ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Uv Irradiation ◽  
Photocatalytic Oxidation ◽  
Air Pollutant ◽  
Benzene Oxidation ◽  
Human Being ◽  
Benzene Removal ◽  
Uv Lamps ◽  
Gaseous Benzene ◽  
Great Harm

Benzene is a toxic air pollutant and causes great harm to human being. Photocatalytic oxidation (PCO) has been frequently studied for benzene removal, however, its PCO efficiency is still very low and the photocatalysts are easy to be deactivated. To improve the efficiency and stability of PCO, UV lamps with partial 185 nm UV irradiation were used to activate photocatalysts (denoted as 185-PCO). Cobalt modified TiO2(Co-TiO2) was developed to improve the PCO activity and eliminate ozone generated from 185 nm UV irradiation. Results show that benzene removal efficiency of PCO with 254 nm UV irradiation (denoted as 254-PCO) is only 2.1% while it was greatly increased to 51.5% in 185-PCO. 185-PCO exhibited superior capacity for benzene oxidation. In the 185-PCO process, much ozone was left in case of TiO2as photocatalysts while it can be nearly eliminated by 1% Co-TiO2.

Photoelectrochemical Degradation of Procion Red MX-5B in TiO2 Suspension Using Na2SO4 as Electrolyte

2010 ◽  
Vol 26-28 ◽  
pp. 637-640
Author(s):  
Wen Jie Zhang ◽  
Ru Yuan Li ◽  
Jia Wei Bai
Keyword(s):  
Reaction Time ◽  
Removal Efficiency ◽  
Uv Irradiation ◽  
Photocatalytic Oxidation ◽  
Electrolyte Concentration ◽  
Dye Decolorization ◽  
Applied Potential ◽  
Toc Removal ◽  
Prolonged Reaction Time

Photoelectrochemical (PEC) degradation of Procion Red MX-5B was investigated in aqueous Na2SO4 solution. Higher electrolyte concentration resulted in higher current between the electrodes due to increased conductivities of the solutions. UV irradiation could obviously raise the current, and the differences became larger in accordance with the increase of the applied potentials. The pH declined in the first 30 minutes and became constant for the prolonged reaction time during both PEC degradation and photocatalytic oxidation. The applied potential could only slightly improve dye decolorization. Although a potential of 8 V was applied to 0.3 mol/l Na2SO4 solution, TOC removal efficiency of PEC degradation was almost as the same as that of photocatalytic oxidation.

Experimental Study on Photocatalytic Pretreatment of Restaurant Wastewater with Nano TiO2

2013 ◽  
Vol 807-809 ◽  
pp. 1575-1578
Author(s):  
Jin Yong Huang ◽  
Li Bin Peng ◽  
Lin Peng
Keyword(s):  
Experimental Study ◽  
Removal Efficiency ◽  
Biological Treatment ◽  
Photocatalytic Oxidation ◽  
Proper Time ◽  
Irradiation Time ◽  
Optimal Conditions ◽  
Oxidation Technology ◽  
Restaurant Wastewater

The study aims at investigating the performance of nanoTiO2photocatalytic oxidation technology for the pretreatment of restaurant wastewater. The rate of lipids removal depends on conditions, such as irradiation time, TiO2dosage, aeration and addition of Fe3+or H2O2.The optimal conditions are determined: proper time of irradiation 10 min, TiO2dosage 25mg/L,pH6.0, adding 5mL Fe3+. Under this optimum, the removal efficiency of lipids reaches 74.7 ~ 88.6%, and that of CODcr was around 45.2~76.2%.While using illumination for 10 min, companied with TiO2and Fe3+/H2O2, the removal efficiency of Grease could increase by 3%~15%.Thus, satisfactory results were achieved for pretreatment of Grease Wastewater from restaurant, and this technique could be used as a pretreatment step for next biological treatment of restaurant wastewater.

Fabrication Study of Hydrophobic Polyurethane Sponge for Oil Absorption Application

2017 ◽  
Vol 751 ◽  
pp. 731-737
Author(s):  
Peeranut Prakulpawong ◽  
Jinjutha Wiriyanantawong ◽  
Janista Pornpoonsawat ◽  
Supan Yodyingyong ◽  
Darapond Triampo
Keyword(s):  
Uv Irradiation ◽  
Oil Spill ◽  
Irradiation Time ◽  
Treatment Method ◽  
Absorption Efficiency ◽  
Oil Absorption ◽  
Uv Treatment ◽  
Simple Method ◽  
Ft Ir ◽  
Oil Spill Cleanup

In this research, the researchers study the fabrication of oil absorption, hydrophobic polyurethane (PU) sponge for application in an oil-spill cleanup model. Virgin PU is initially hydrophilic. PU is made hydrophobic by incorporating hydrophobic silica aerogel (SA) into PU 3D porous structure by stirring method and UV-treatment method. UV-irradiation promotes the attachment of SA onto the PU surface. Varying UV irradiation time and concentration of SA is done to attain an optimal attachment of SA on PU. Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), contact angle measurements (CA) are used to determine the adhesion of SA on PU. The loadings of SA with and without UV-treatment are compared. Results show that SA-PU with UV-treatment has more loading of SA than SA-PU without treatment. FT-IR spectra and SEM micrographs verify the results. Moreover, the SA-PU is tested for oil absorption to simulate oil-spill cleanup. The findings show fast (less than 3 seconds), recoverable oil-spills cleanup with simple method of preparation. In addition, SA-PU with UV treatment has higher absorption rate and %absorption efficiency when compared to original PU and SA-PU without UV treatment.

scholarly journals The degradation of phenol in water solution by TiO2 photocatalysis in a helical reactor

2013 ◽  
Vol 10 (3) ◽  
pp. 404-418 ◽  
Keyword(s):  
Titanium Dioxide ◽  
Light Intensity ◽  
Uv Irradiation ◽  
Photocatalytic Oxidation ◽  
Irradiation Time ◽  
Water Solution ◽  
Phenol Degradation ◽  
Flow Mode ◽  
Order Kinetic ◽  
Wide Range

Heterogeneous photocatalysis is an advanced oxidation process (AOP) which has been widely studied by numerous researchers in the world and is used to degrade or remove a wide range of pollutants in water and air. The photocatalytic oxidation and mineralization of phenol in aqueous catalyst suspensions of titanium dioxide (TiO2) Degussa P25 (80% anatase, 20% rutile) has been carried out in a helical reactor. The photodegradation was investigated using two kinds of high pressure mercury irradiation lamps one emitting at 254 nm (15 Watts) and the other emitting at 365 nm (400 Watts). The effects of the recirculation flow, source of withdrawal, initial phenol concentration, amount of catalyst, suspension pH and light intensity on photodegradation of phenol were investigated. These parameters were studied to find the optimal conditions for a complete and fast oxidation of this organic compound. Kinetic experiments were performed at 32 oC over a range of phenol concentrations from 2.5 to 25 mg l-1, a range of TiO2 concentrations from 0.1 to 1 g l1, a range of suspensions pH from 3 to 9. The helical reactor was operated under a continuous flow-mode. Results showed that photodegradation is an effective method for the removal of phenol from wastewaters. The efficiency of the process depends strongly on the experimental conditions. The amount of catalyst, UV irradiation time, pH and light intensity were important parameters in the degradation process. The rate constants for the different parameters (TiO2, phenol concentration) were evaluated. Kinetic studies showed that titanium dioxide photocatalyst P25 was very active in phenol degradation; we observed that 99% of pollutant was degraded after 6 hours of UV irradiation; furthermore, we observed that phenol degradation was more effective under acidic conditions than alkaline. The kinetics were described by the Langmuir- Hinshelwood (L-H) kinetic model. An overall pseudo-first order kinetic constant has been calculated for phenol conversion and values obtained in acidic pH are higher than those calculated for basic pH media.

scholarly journals Albumin/Ag Nanoparticles Synthesized by Using UV-Irradiation and Estimation of Their Antibacterial Activity

2020 ◽  
pp. 36-45
Author(s):  
Randa Fawzi Elsupikhe ◽  
Tahani Soliman Alfazani ◽  
Fawzia Muftah Al-Jazwia ◽  
Hitham. Abo-Eisa ◽  
Imperiyka Hammad ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Uv Irradiation ◽  
Irradiation Time ◽  
Average Diameter ◽  
Bulk Sample ◽  
Inhibitory Effect ◽  
Optimum Conditions ◽  
Ag Nps ◽  
Albumin Nanoparticles ◽  
Uv Lamp

Nano-scale (less than 100 nm) materials have received wide attention because of their rare properties that differ significantly from a bulk sample of the same material. In this research, a physical irradiation method by using UV lamp was established for preparation nanoparticles colloids of silver nanoparticles (Ag-NPs) with an eco-friendly stabilizer (Albumin). The preparation process was carried out using silver nitrate (AgNO3) in aqueous albumin at room temperature. The effects of UV-irradiation time and the concentrations of Ag+ and albumin on the particle size have been investigated. Moreover, the antibacterial effect of the Ag/Albumin nanoparticles has been tested. The results showed that, the UV–irradiation can influence the Ag-NPs size, which the of Nps  decreases with the UV–irradiation increases. The morphological study demonstrated well-dispersed spherical Ag-NPs with an average diameter of about 29 nm at the optimum conditions. The antibacterial results exhibited a significant inhibitory effect for the Ag-NPs that synthesized in this work. The current fabrication method of the silver nanoparticles colloid could be extended to other metals such as Cu- Nps and may possibly find various additional applications.    

scholarly journals UV-Enhanced NaClO Oxidation of Nitric Oxide from Simulated Flue Gas

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Shao-long Yang ◽  
Zhi-tao Han ◽  
Jing-ming Dong ◽  
Zi-sheng Zheng ◽  
Xin-xiang Pan
Keyword(s):  
Removal Efficiency ◽  
Uv Irradiation ◽  
Flue Gas ◽  
Ph Value ◽  
Irradiation Time ◽  
Reaction Chamber ◽  
Active Species ◽  
Chlorine Concentration ◽  
No Removal ◽  
Initial Ph

A wet de-NOxtechnique based on an UV-enhanced NaClO oxidation process was investigated for simulated flue gas of a diesel engine using a bench-scale reaction chamber. The effects of UV irradiation time, initial pH value, and available chlorine concentration of NaClO solution were studied, respectively. The results showed that when the UV irradiation time was 17.5 min and the initial pH value of NaClO solution was 6, NO removal efficiency of UV/NaClO solution was increased by 19.6% compared with that of NaClO solution. Meanwhile, when the available chlorine concentration of NaClO solution decreased from 0.1 wt% to 0.05 wt%, the enhancement in NO removal efficiency of UV/NaClO solution increased from 19.6% to 24%, compared with that of NaClO solution. The reaction pathways of NaClO solution photolysis and NO removal by UV/NaClO process were preliminarily discussed. The results suggested that HOCl might be the most active species that released many UV-induced photooxidants through photolysis reactions, which played an important role in NO removal process.

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