scholarly journals Photocatalytic Degradation of Polynitrophenols on Various Commercial Suspended or Deposited Titania Catalysts Using Artificial and Solar Light

2008 ◽  
Vol 2008 ◽  
pp. 1-9 ◽  
Author(s):  
Hinda Lachheb ◽  
Ammar Houas ◽  
Jean-Marie Herrmann
Keyword(s):  
Chemical Oxygen Demand ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Degradation Rate ◽  
Oxygen Demand ◽  
Solar Light ◽  
Test Reactions ◽  
Anionic Species ◽  
Paper Fibers ◽  
Purification Of Water

Phenol (PH) and three polynitrophenols (4-nitrophenol (PNP), 2,4-dinitrophenol (DNP), 2,4,6-trinitrophenol (TNP)) were photocatalytically degraded by using titania under either artificial or solar light. These four reactions were chosen as test reactions to compare the efficiencies of two suspended commercial titania photocatalysts (Degussa P-25 and Millennium PC-500). It appears that P-25 has a higher initial efficiency in all nitrophenol disappearance reactions. However, for the overall degradation rate, measured by the chemical oxygen demand (COD) disappearance, the performance of PC-500 was similar to that of P25. This was attributed to a favorable textural effect since PC-500 has a much higher surface area which facilitates the readsorption of intermediates. PC-500 was subsequently supported on a special photoinert paper provided by Ahlstrom Company (38-Pont Evèque, France). The influence of the silica binder used for sticking titania particles on the paper fibers was put in evidence as an inhibitor of the coulombic adsorption of anionic species, especially 2,4,6-trinitrophenol, because of the low pzc of silica. Once validated, this supported photocatalyst was introduced in an autonomous solar pilot photoreactor identical to the several prototypes built in the European AQUACAT program. It was demonstrated that the purification of water could be efficiently obtained in a larger scale without any final tedious filtration.

scholarly journals TiO2 BEADS FOR PHOTOCATALYTIC DEGRADATION OF HUMIC ACID IN PEAT WATER

2011 ◽  
Vol 11 (3) ◽  
pp. 253-257 ◽  
Author(s):  
Winarti Andayani ◽  
Agustin N M Bagyo
Keyword(s):  
Aqueous Solution ◽  
Humic Acid ◽  
Oxalic Acid ◽  
Chemical Oxygen Demand ◽  
Photocatalytic Degradation ◽  
Uv Light ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Color Intensity ◽  
Before And After

Degradation of humic acid in aqueous solution containing TiO2 coated on ceramics beads under irradiation of 254 nm UV light has been conducted in batch reactor. The aim of this experiment was to study photocatalytic degradation of humic acid in peat water. The irradiation of the humic acid in aqueous solution was conducted in various conditions i.e solely uv, in the presence of TiO2-slurry and TiO2 beads. The color intensity, humic acid residue, conductivity and COD (chemical oxygen demand) of the solution were analyzed before and after irradiation.  The compounds produced during photodegradation were identified using HPLC. The results showed that after photocatalytic degradation, the color intensity and the COD value of the solution decreased, while the conductivity of water increased indicating mineralization of the peat water occurred. In addition, oxalic acid as the product of degradation was observed.

The role of oxygen vacancy over ZnCr-layered double oxide in enhancing solar light-driven photocatalytic degradation of bisphenol A

2018 ◽  
Vol 15 (4) ◽  
pp. 226 ◽  
Author(s):  
Meiqing Chen ◽  
Pingxiao Wu ◽  
Qianqian Wei ◽  
Yajie Zhu ◽  
Shanshan Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Bisphenol A ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Organic Pollutants ◽  
Oxygen Vacancies ◽  
Solar Light ◽  
X Ray ◽  
Vis Spectroscopy

Environmental contextAn important goal in attempts to degrade environmental organic pollutants is the development of a photocatalyst that is responsive to visible light. We report a facile method for preparing a zinc-based photocatalyst with oxygen vacancies that efficiently degrades bisphenol A under solar light irradiation. The study will stimulate further investigations into the efficacy of other metal oxide nanostructures for the photocatalytic degradation of organic pollutants. AbstractTwo ZnCr-layered double oxides (ZnCr-LDO) were fabricated via different thermal treatment of the ZnCr-layered double hydroxide (ZnCr-LDH) precursor. ZnCr-V-700 and ZnCr-A-700 were obtained at 700 °C under vacuum and air, respectively. As X-ray diffraction revealed, both ZnCr-V-700 and ZnCr-A-700 were made up of ZnO and ZnCr2O4 spinel, and ZnCr-V-700 displayed a lower crystallinity and many uniform particles with oxygen vacancies. Scanning electron microscopy and transmission electron microscopy revealed that the particle size of ZnCr-V-700 was ~30 nm and its disordered crystallinity suggested the existence of oxygen vacancies. Notably, the ZnCr-LDO materials showed remarkably enhanced photocatalytic activity compared to the ZnCr-LDH precursor. ZnCr-V-700 was the most active material and more than 90 % of BPA was degraded after irradiation for 200 min with high mineralisation (up to 37 %). The results of Brunauer–Emmett–Teller surface area analysis, X-ray photoelectron spectroscopy, Raman and UV-vis spectroscopy and electron paramagnetic resonance spectroscopy showed that oxygen vacancies incorporated into ZnCr-V-700 played a key role in improving the photocatalytic performance by enhancing interfacial charge transfer and restricting the charge recombination. In addition, the uniform particle size, larger surface area and the coexistence of ZnO and ZnCr2O4 also played a synergistic role. In conclusion, this work not only provides a facile and low-cost method to prepare photocatalysts for treatment of wastewater containing BPA, but also supplies a new idea for improving the performance of photocatalysts.

scholarly journals Comparison between the photocatalytic degradation of single and binary azo dyes in TiO2 suspensions under solar light irradiation

2015 ◽  
Vol 5 (4) ◽  
pp. 579-591 ◽  
Author(s):  
Ohm-Mar Min ◽  
Li-Ngee Ho ◽  
Soon-An Ong ◽  
Yee-Shian Wong
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Photocatalytic Degradation ◽  
Azo Dyes ◽  
Azo Dye ◽  
Oxygen Demand ◽  
Light Irradiation ◽  
Solar Light ◽  
Acid Orange 7 ◽  
Solar Light Irradiation

Textile industries discharge a large quantity of colored wastewater which is harmful to the ecosystem. In this study, two kinds of dyes were investigated: the mono azo Acid Orange 7 (AO7) and diazo Reactive Green 19 (RG19). The photocatalytic degradation of single (AO7, RG19) azo dye and binary (AO7 and RG19 mixture) azo dye aqueous solutions was photocatalyzed by commercial titanium dioxide (TiO2, P25) under solar light irradiation. The objectives of this study are to compare the photocatalytic degradation between single and binary azo dye aqueous solution and to study the various parameters such as the effect of different initial azo dye concentrations, different initial azo dye pH values, and compare the adsorption capacity of azo dyes with and without solar light irradiation, which influences the photocatalytic activities of single and binary azo dye aqueous solutions in a TiO2 suspension. The results showed that photocatalytic degradation of AO7 and RG19 in a single azo dye aqueous solution was faster than a binary azo dye solution under the solar light irradiation process. Chemical oxygen demand results revealed that complete mineralization could be achieved for both AO7 and RG19 azo dyes under solar light irradiation within 22 hours.

Preparation and Characterization of La-B Co-Doped TiO2 Photocatalyst

2013 ◽  
Vol 859 ◽  
pp. 333-336
Author(s):  
Hai Chun Chen ◽  
Xiao Bei Pei
Keyword(s):  
Methyl Orange ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Pore Volume ◽  
Degradation Rate ◽  
Solvothermal Method ◽  
Tetrabutyl Titanate ◽  
Degradation Activity ◽  
Co Doped

La-B-TiO2photocatalysts were prepared using tetrabutyl titanate, tributyl borate, and lanthanum chloride as the precursors by solvothermal method. The prepared sample is composed of irregular particles with fairly rough surface in the size within 5 μm. Large surface area and pore volume are benefit to adsorption and photocatalytic degradation activity of the materials. Pore size of the 1%La-3%B-TiO2sample mainly distributes in the range between 5-35 nm. Specific surface area of the material is 101.45 m2/g. The sample containing 0.5% La presents the maximum decoloration efficiency. When La content is 0.5%, methyl orange adsorption rate on the material is less than 5%, and photocatalytic degradation rate is 39.9%.

scholarly journals Improved Ozonation Efficiency for Polymerization Mother Liquid from Polyvinyl Chloride Production Using Tandem Reactors

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4436 ◽  
Author(s):  
Zhiyong Yang ◽  
Penglei Wang ◽  
Yagang Zhang ◽  
Xingjie Zan ◽  
Wenjuan Zhu ◽  
...  
Keyword(s):  
Reaction Time ◽  
Chemical Oxygen Demand ◽  
Polyvinyl Chloride ◽  
Ozone Concentration ◽  
Degradation Rate ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Utilization Efficiency ◽  
High Ozone Concentration ◽  
In Series

Polymerization mother liquid (PML) is one of the main sources of wastewater in the chlor-alkali industry. The effective degradation of the PML produced in PVC polymerization using three or five ozone reactors in tandem was designed with a focus on improving the ozonation efficiency. The ozonation efficiency of the tandem reactors for the degradation of PML, along with the effect of ozone concentration, the number of reactors utilized in series, and the reaction time on the chemical oxygen demand (COD) removal were investigated in detail. The results showed that the COD removal increased as the ozone concentration was increased from 10.6 to 60 mg·L−1, achieving 66.4% COD removal at ozone concentration of 80.6 mg·L−1. However, when the ozone concentration was increased from 60 mg·L−1 to 80 mg·L−1, the COD removal only increased very little. The COD decreased with increasing ozone concentration. During the initial degradation period, the degradation rate was the highest at both low and high ozone concentrations. The degradation rate decreased with reaction time. The rate at a low ozone concentration decreased more significantly than at high ozone concentration. Although high ozone concentration is desirable for COD removal and degradation rate, the utilization efficiency of ozone decreased with increasing ozone concentration. The ozone utilization efficiency of the five-reactor device was three times higher than that of three tandem reactors, demonstrating that ozonation utilization efficiency can be improved by increasing the number of tandem reactors. Ozonation in tandem reactors is a promising approach for PML treatment.

Influence of photoperiod on carbon dioxide and methane emissions from two pilot-scale stabilization ponds

2012 ◽  
Vol 66 (9) ◽  
pp. 1930-1940 ◽  
Author(s):  
Juan P. Silva ◽  
José L. Ruiz ◽  
Miguel R. Peña ◽  
Henk Lubberding ◽  
Huub Gijzen
Keyword(s):  
Carbon Dioxide ◽  
Chemical Oxygen Demand ◽  
Greenhouse Gas ◽  
Co2 Emissions ◽  
Ghg Emissions ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
The Other ◽  
Solar Light ◽  
Static Chamber

Greenhouse gas (GHG) emissions (CO2, CH4) from pilot-scale algal and duckweed-based ponds (ABP and DBP) were measured using the static chamber methodology. Daylight and nocturnal variations of GHG and wastewater characteristics (e.g. chemical oxygen demand (COD), pH) were determined via sampling campaigns during midday (12:30–15:30) and midnight (00:30–03:30) periods. The results showed that under daylight conditions in ABP median emissions were −232 mg CO2 m−2 d−1 and 9.9 mg CH4 m−2 d−1, and in DBP median emissions were −1,654.5 mg CO2 m−2 d−1 and 71.4 mg CH4 m−2 d−1, respectively. During nocturnal conditions ABP median emissions were 3,949.9 mg CO2 m−2 d−1, 12.7 mg CH4 m−2 d−1, and DBP median emissions were 5,116 mg CO2 m−2 d−1, 195.2 mg CH4 m−2 d−1, respectively. Once data measured during daylight were averaged together with nocturnal data the median emissions for ABP were 1,566.8 mg CO2 m−2 d−1 and 72.1 mg CH4 m−2 d−1, whilst for DBP they were 3,016.9 mg CO2 m−2 d− and 178.9 mg CH4 m−2 d−1, respectively. These figures suggest that there were significant differences between CO2 emissions measured during daylight and nocturnal periods (p < 0.05). This shows a sink-like behaviour for both ABP and DBP in the presence of solar light, which indicates the influence of photosynthesis in CO2 emissions. On the other hand, the fluxes of CH4 indicated that DBP and ABP behave as net sources of CH4 during day and night, although higher emissions were observed from DBP. Overall, according to the compound average (daylight and nocturnal emissions) both ABP and DBP systems might be considered as net sources of GHG.

ZnO Photocatalysis Using Solar Energy for the Removal of Trace Amounts of Alfa-Methylstyrene, Diquat and Indigo Carmine from Water

2014 ◽  
Vol 17 (2) ◽  
Author(s):  
O. M. Shibin ◽  
B. Rajeev ◽  
V. Veena ◽  
E. P. Yesodharan ◽  
Yesodharan Suguna
Keyword(s):  
Visible Light ◽  
Chemical Oxygen Demand ◽  
Photocatalytic Degradation ◽  
Uv Light ◽  
Indigo Carmine ◽  
Parent Compound ◽  
Oxygen Demand ◽  
Solar Photocatalyst ◽  
Significant Chemical ◽  
Trace Pollutants

AbstractSemiconductor photocatalysis using ZnO has been extensively investigated for the chemical and bacterial decontamination of water and air. In most of these cases, UV light is the source of energy and visible light induced photocatalytic degradation of trace pollutants in water has not received adequate attention. In the present study, ZnO is evaluated as a solar photocatalyst for the removal of trace amounts of three typical pollutants, i.e. alpha- Methylstyrene (AMS, a petrochemical), Diquat (herbicide) and Indigo carmine (IC, a dye) from water. Degradation by itself does not result in complete mineralisation and decontamination as seen from the significant Chemical Oxygen Demand even after the parent compound has disappeared. However, the intermediates also get mineralized eventually. The study indicates that solar photocatalysis can be used as a viable tool for the purification water contaminated with these chemicals. The degradation follows variable kinetics depending on the concentration of the substrates. H

Adsorption and photocatalytic degradation of pharmaceuticals and pesticides by carbon doped-TiO2 coated on zeolites under solar light irradiation

2016 ◽  
Vol 73 (12) ◽  
pp. 2868-2881 ◽  
Author(s):  
Ye An ◽  
David Johannes de Ridder ◽  
Chun Zhao ◽  
Klaas Schoutteten ◽  
Julie Vanden Bussche ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Surface Area ◽  
Light Irradiation ◽  
Solar Light ◽  
Hospital Wastewater ◽  
Doped Tio2 ◽  
Carbon Doped ◽  
Composite Catalysts ◽  
Solar Light Irradiation ◽  
Wastewater Samples

Abstract To evaluate the performance of zeolite-supported carbon-doped TiO2 composite catalysts toward target pollutants under solar light irradiation, the adsorption and photocatalytic degradation of 18 pharmaceuticals and pesticides with distinguishing features (molecular size and volume, and photolysis) were investigated using mordenite zeolites with SiO2/Al2O3 ratios of 18 and 240. Different quantities of carbon-doped TiO2 were coated on the zeolites, and then the finished composite catalysts were tested in demineralized, surface, and hospital wastewater samples, respectively. The composite photocatalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, and surface area and porosity analyses. Results showed that a dispersed layer of carbon-doped TiO2 is formed on the zeolite surface; this layer blocks the micropores of zeolites and reduces their surface area. However, these reductions did not significantly affect adsorption onto the zeolites. Our results demonstrated that zeolite-supported carbon-doped TiO2 systems can effectively degrade 18 pharmaceuticals and pesticides in demineralized water under natural and simulated solar light irradiation. In surface and hospital wastewaters, zeolite-supported carbon-doped TiO2 systems present excellent anti-interference capability against radical scavengers and competitive organics for pollutants removal, and higher pollutants adsorption on zeolites evidently enhances the removal rate of target pollutants in surface and hospital wastewater samples with a complicated matrix.

scholarly journals Photocatalytic Removal of Microcystin-LR by Advanced WO3-Based Nanoparticles under Simulated Solar Light

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Chao Zhao ◽  
Dawei Li ◽  
Yonggang Liu ◽  
Chuanping Feng ◽  
Zhenya Zhang ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Photocatalytic Oxidation ◽  
Chloride Ion ◽  
Solar Light ◽  
Order Kinetic ◽  
First Order ◽  
Simulated Solar Light ◽  
Photocatalytic Removal ◽  
Order Kinetic Model ◽  
Purification Of Water

A series of advanced WO3-based photocatalysts including CuO/WO3, Pd/WO3, and Pt/WO3were synthesized for the photocatalytic removal of microcystin-LR (MC-LR) under simulated solar light. In the present study, Pt/WO3exhibited the best performance for the photocatalytic degradation of MC-LR. The MC-LR degradation can be described by pseudo-first-order kinetic model. Chloride ion (Cl−) with proper concentration could enhance the MC-LR degradation. The presence of metal cations (Cu2+and Fe3+) improved the photocatalytic degradation of MC-LR. This study suggests that Pt/WO3photocatalytic oxidation under solar light is a promising option for the purification of water containing MC-LR.

Sign in / Sign up

Export Citation Format

Share Document