scholarly journals Laboratory and Pilot-Plant Scale Photocatalytic Degradation of Polychlorinated Biphenyls in Seawater Using CM-n-TiO2Nanoparticles

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Yasser A. Shaban ◽  
Mohamed A. El Sayed ◽  
Amr A. El Maradny ◽  
Radwan Kh. Al Farawati ◽  
Mosa I. Al Zobidi ◽  
...  

Photocatalytic degradation of polychlorinated biphenyls (PCBs) in seawater was successfully achieved at laboratory level with UV light and at pilot-plant scale under natural solar radiation using carbon-modified titanium oxide (CM-n-TiO2) nanoparticles. The photocatalytic performance of CM-n-TiO2was comparatively evaluated with reference n-TiO2under identical conditions. As a result of carbon incorporation, significant enhancement of photodegradation efficiency using CM-n-TiO2was clearly observed. To optimize the operating parameters, the effects of catalyst loading and pH of the solution on the photodegradation rate of PCBs were investigated. The best degradation rate was obtained at pH 5 and CM-n-TiO2loading of 0.5 g L−1. The photodegradation results fitted the Langmuir-Hinshelwood model and obeyed pseudo-first-order reaction kinetics.

2021 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
Hartini Ahmad Rafaie ◽  
Nur Fitrahana Mohd Yusop ◽  
Nurathira Faqihah Azmi ◽  
Nur Syakirah Abdullah ◽  
Nurul Infaza Talalah Ramli

Zinc oxide (ZnO) powder was used as a photocatalyst for the photocatalytic degradation of methylene blue (MB) dye solution. In this study, different amount of ZnO (10, 20 and 30 mg) as photocatalyst was used to investigate the performance of photocatalytic degradation of MB dye solution. The morphology and structural properties of ZnO powder were studied by X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) techniques. The photocatalytic activities of the ZnO powder were investigated by degrading the MB dye solution under UV light irradiation at different amounts of ZnO photocatalyst. The percentage degradation of MB dye solution in the presence of 10 mg ZnO powder was found to be the highest at 96.2 % within 60 min irradiation compared to 20 and 30 mg of ZnO powder. The photodegradation rate constants, k obtained in this study were 0.0661, 0.0558, and 0.0507 min-1 for 10, 20, and 30 mg ZnO powder, respectively that follow the pseudo first-order reaction kinetics. Keywords: Methylene blue, photocatalytic degradation, photocatalyst, Zinc Oxide


2017 ◽  
Vol 14 (3) ◽  
pp. 582-587
Author(s):  
Baghdad Science Journal

In this work, the photocatalytic degradation of indigo carmine (IC) using zinc oxide suspension was studied. The effect of influential parameters such as initial indigo carmine concentration and catalyst loading were studied with the effect of Vis irradiation in the presence of reused ZnO was also investigated. The increased in initial dye concentration decreased the photodegradation and the increased catalyst loading increased the degradation percentage and the reused-ZnO exhibits lower photocatalytic activity than the ZnO catalyst. It has been found that the photocatalytic degradation of indigo carmine obeyed the pseudo-first-order kinetic reaction in presence of zinc oxide. This was found from plotting the relationship between ln (C0/Ct) and irradiation the rate constant of the process.UV- spectrophotometer was used to study the indigo carmine photodegradation.


2018 ◽  
Vol 5 (4) ◽  
pp. 171457 ◽  
Author(s):  
Zhigang Yi ◽  
Juan Wang ◽  
Tao Jiang ◽  
Qiong Tang ◽  
Ying Cheng

In this study, photocatalytic experiments of 20 mg l −1 sulfamethazine (SMN) in aqueous solution containing ZnO with different morphologies, tetra-needle-like ZnO (T-ZnO), flower-like ZnO (F-ZnO) and nanoparticles ZnO (P-ZnO), were performed. The results indicated that photocatalytic degradation of SMN was effective and followed the pseudo-first-order reaction, but the degree of SMN mineralization showed obvious differences using ZnO with different shapes. After 12 h irradiation, 86%, 71% and 50% of the initial total organic carbon was eliminated in SMN suspension containing T-ZnO, F-ZnO and P-ZnO, respectively. The release ratio of sulfur was close to 100% in the presence of T-ZnO, but reached to 86% and 67% in the presence of F-ZnO and P-ZnO, respectively. The release ratio of nitrogen was about 76%, 63% and 40% using T-ZnO, F-ZnO and P-ZnO as photocatalyst, respectively. The morphology of ZnO played an important role in determining its catalytic activity. Seven intermediates were observed and identified in the UV/T-ZnO reaction system by LC-MS/MS analysis, and a possible degradation pathway was proposed.


2014 ◽  
Vol 665 ◽  
pp. 455-458
Author(s):  
Li Guo ◽  
Jin Huang ◽  
Jun Wu ◽  
Lei Lei Luo

The photodegradation of 4,4-bis (4-hydroxyphenyl) pentanoic acid (DPA) with two cyclodextrins (α-CD and β-CD ) in aqueous solutions induced by UV-light was studied in this paper by means of fluorescence spectra and high efficiency liquid chromatography. The result suggested that DPA with α-CD or β-CD formed inclusion compound in aqueous solutions. The photodegradation of DPA with two cyclodextrins or without cyclodextrin was pseudo-first order reaction. The photodegradation of DPA was accelerated by the addition of β-CD in aqueous solutions, but the that of DPA was inhibited in case of adding α-CD. These differences were due to the differences in inclusion interaction of DPA with α-CD or β-CD.


2007 ◽  
Vol 129 (1-2) ◽  
pp. 59-68 ◽  
Author(s):  
Javier Marugán ◽  
Jose Aguado ◽  
Wolfgang Gernjak ◽  
Sixto Malato

Author(s):  
Seyfeddine Bendjabeur ◽  
Razika Zouaghi ◽  
O.N.H Kaabeche ◽  
Tahar Sehili

Abstract The photocatalytic decolorization of Gentian violet (GV) from an aqueous solution was studied by focusing on comparison of the photoactivity of different type of TiO2 catalyst. The process was carried out under a variety of conditions. The efficiency of P25-Degussa and PC50-Millennium photocatalysts were compared. The effect of different parameters such as pH, initial dye concentration, catalyst loading and the presence of some anions on both adsorption in the absence of light and the degradation under UV irradiation have been studied. 365 nm UV-A lamp was employed as irradiation source. The kinetic study showed that no correlation was observed between the adsorption capacity of the catalyst and its photoactivity, despite of this the effect of various parameters on adsorption and photocatalytic kinetic behavior was practically similar on various catalysts. The photocatalytic degradation of GV followed first-order reaction kinetics and the higher adsorption and photocatalytic degradation were obtained at the alkaline medium (pH = 10 for P25 and pH = 8 for PC50). However, the reaction at the acidic medium was gradually delayed due to the effect of charge repulsion. The presence of some anions (Cl−, SO42−, NO3−) in the medium at higher concentration was found to reduce the adsorption and to inhibit the degradation.


1998 ◽  
Vol 37 (8) ◽  
pp. 187-194 ◽  
Author(s):  
Tsu-feng Chen ◽  
Ruey-an Doong ◽  
Wen-gang Lei

The photodegradation of parathion in the direct photolysis, UV/TiO2, UV/H2O2 and UV/TiO2/H2O2 systems was investigated at 25°C. The effect of light intensity was also examined to clarify the relationship between the photo flux and decomposition rate of parathion. Results of the study demonstrated that no obvious degradation of parathion in dark reaction occurred within 24 hours. However, the addition of TiO2 and/or H2O2 promotes the degradation efficiency of parathion. Adding H2O2 was more effective in the photocatalytic oxidation of parathion than TiO2. Also, hydrogen peroxide was found as an intermediate with the maximum concentration of 55 μM in UV/TiO2 system during the photodegradation of parathion. A higher intensity of lamp could increase the degradation rate of parathion. However, the quantum efficiency for degradation of parathion decreased from 0.053 to 0.006 when light intensity increased from 100 W to 450W. Photodecomposition followed a pseudo-first-order reaction. The rate constants of parathion ranged from 0.003 min−1 for direct photolysis to 0.023 min−1 for UV/TiO2/H2O2 system. This study indicated that photocatalytic degradation is a highly promising technology for detoxifying parathion.


Solar Energy ◽  
1996 ◽  
Vol 56 (5) ◽  
pp. 387-400 ◽  
Author(s):  
D. Curcó ◽  
S. Malato ◽  
J. Blanco ◽  
J. Giménez ◽  
P. Marco

2012 ◽  
Vol 77 (12) ◽  
pp. 1747-1757 ◽  
Author(s):  
Veljko Djokic ◽  
Jelena Vujovic ◽  
Aleksandar Marinkovic ◽  
Rada Petrovic ◽  
Djordje Janackovic ◽  
...  

The photocatalytic degradation of synthetic textile dye CI Basic Yellow 28 (BY28) in water, using recently synthesized P160 TiO2 based catalyst, under Osram ultra-vitalux? lamp (300 W) light, was studied. The effect of the operational parameters such as initial concentration of catalyst, initial dye concentration and pH was studied. Salt effect was also investigated (NaCl, Na2CO3, Na2SO4, NaNO3). It was found that the optimal concentration of catalyst is 2.0 g L-1. A pseudo first-order kinetic model was illustrated using the Langmuir-Hinshelwood mechanism, and the adsorption equilibrium constant and the rate constant of the surface reaction were calculated (KBY = 6.126 L mg-1 and kC = 0.272 mg L-1 min-1, respectively). The photodegradation rate was higher in weak acidic than in high acidic and alkaline conditions. The presence of CO32- ions increases the photodegradation rate while Cl-, SO42- and NO3-ions decreases the reaction rate. The rate of photodegradation of BY28 was measured using UV-Vis spectroscopy.


2013 ◽  
Vol 781-784 ◽  
pp. 2249-2252 ◽  
Author(s):  
Sanni O. Saheed ◽  
Sekomeng J. Modise ◽  
Allworth M. Sipamla

Titania dispersed on dealuminated Clinoptilotile (TiO2/HCP) was synthesized and characterized by Scanning Electron Microscope (SEM). Supporting characterization techniques reveals partly dispersion of TiO2 within the cavities of dealuminated Clinoptilotile (HCP) and TiO2 exist as nanoparticles or clusters on the HCP surface ascribed to lower loading of TiO2. The photocatalytic degradation of methyl orange solution was conducted under UV-irradiation in the presence of TiO2/HCP. The photocatalytic degradation of methyl orange in the presence of the photocatalyst was optimized at lower loading of TiO2, at a lower initial dye concentration (30 ppm), calcination temperature of 873K and nitrate ion accelerates degradation activities of methyl orange. Kinetic studies depict the photocatalytic degradation of methyl orange follows the pseudo-first order reaction.


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