A Comparative Study of Supported TiO2 as Photocatalyst in Water Decontamination at Solar Pilot Plant Scale

2005 ◽  
Vol 128 (3) ◽  
pp. 331-337 ◽  
Author(s):  
Mahmut Kus ◽  
Wolfgang Gernjak ◽  
Pilar Fernández Ibáñez ◽  
Sixto Malato Rodríguez ◽  
Julián Blanco Gálvez ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Organic Compounds ◽  
High Performance ◽  
Sol Gel ◽  
Silver Deposition ◽  
Force Microscopy ◽  
Glass Tubes ◽  
Degussa P25 ◽  
Pilot Plant Scale

The degradation of gallic acid and imidacloprid with supported Millennium PC500 and Degussa P25 TiO2 is reported. TiO2 particles were immobilized using a titanium sol-solution and direct deposition on glass supports. The film characterization was done by x-ray diffraction, scanning electron microscopy, and atomic force microscopy, and degradation of organic compounds was monitored by high-performance liquid chromatography, total organic carbon analyzer, and ion chromatography. The experiments were performed under sunlight in compound parabolic collector plants with flat supports inside the glass tubes. Photocatalytic activity of the films was compared and identified. Although sol-gel coatings had better mechanical properties, mineralization was observed to be approximately five times slower than paste-deposited films. Photoactivity of the films decreased with silver deposition due to the nature of the organic compounds. The rate constants were calculated to be between 2×10−1 and 6×10−2mgm2∕kJ for organic compounds, and 6×10−2 and 6×10−3 for total organic carbon.

Preparation and Photocatalytic Activity of Mixed Phase Anatase/rutile TiO2 Nanoparticles for Phenol Degradation

2014 ◽  
Vol 70 (2) ◽  
Author(s):  
Mohamad Azuwa Mohamed ◽  
Wan Norharyati Wan Salleh ◽  
Juhana Jaafar ◽  
Norhaniza Yusof
Keyword(s):  
Photocatalytic Activity ◽  
Tio2 Nanoparticles ◽  
High Performance ◽  
Sol Gel ◽  
Phenol Degradation ◽  
Chemical Properties ◽  
Mixed Phase ◽  
Rutile Tio2 ◽  
Physico Chemical ◽  
Degussa P25

The evolution of desirable physico-chemical properties in high performance photocatalyst materials involves steps that must be carefully designed, controlled, and optimized. This study investigated the role of key parameter in the preparation and photocatalytic activity analysis of the mixed phase of anatase/rutile TiO2 nanoparticles, prepared via sol-gel method containing titanium-n-butoxide Ti(OBu)4 as a precursor material, nitric acid as catalyst, and isopropanol as solvent. The prepared TiO2 nanoparticles were characterized by means of XRD, SEM, and BET analyses, and UV-Vis-NIR spectroscopy. The results indicated that the calcination temperature play an important role in the physico-chemical properties and photocatalytic activity of the resulting TiO2 nanoparticles. Different calcination temperatures would result in different composition of anatase and rutile. The photocatalytic activity of the prepared mixed phase of anatase/rutile TiO2 nanoparticles was measured by photodegradation of 50 ppm phenol in an aqueous solution. The commercial anatase from Sigma-Aldrich and Degussa P25 were used for comparison purpose. The mixed phase of anatase/rutile TiO2 nanoparticles (consists of 38.3% anatase and 61.7% rutile) that was prepared at 400°C exhibited the highest photocatalytic activity of 84.88% degradation of phenol. The result was comparable with photocatalytic activity demonstrated by Degussa P25 by 1.54% difference in phenol degradation. The results also suggested that the mixed phase of anatase/rutile TiO2 nanoparticles is a promising candidate for the phenol degradation process. The high performance of photocatalyst materials may be obtained by adopting a judicious combination of anatase/rutile and optimized calcination conditions.

scholarly journals Treatment Efficiency by means of a Nonthermal Plasma Combined with Heterogeneous Catalysis of Odoriferous Volatile Organic Compounds Emissions from the Thermal Drying of Landfill Leachates

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Daniel Almarcha ◽  
Manuel Almarcha ◽  
Elena Jimenez-Coloma ◽  
Laura Vidal ◽  
Montserrat Puigcercós ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Organic Compounds ◽  
Nonthermal Plasma ◽  
Sulphur Compounds ◽  
Odor Concentration ◽  
Volatile Organic ◽  
Thermal Drying ◽  
Urban Solid Waste

The objective of the present work was to assess the odoriferous volatile organic compounds depuration efficiency of an experimental nonthermal plasma coupled to a catalytic system used for odor abatement of real emissions from a leachate thermal drying plant installed in an urban solid waste landfill. VOC screening was performed by means of HRGC-MS analysis of samples taken at the inlet and at the outlet of the nonthermal plasma system. Odor concentration by means of dynamic olfactometry, total organic carbon, mercaptans, NH3, and H2S were also determined in order to assess the performance of the system throughout several days. Three plasma frequencies (100, 150, and 200 Hz) and two catalyst temperatures (150°C and 50°C) were also tested. Under conditions of maximum capacity of the treatment system, the results show VOC depuration efficiencies around 69%, with average depuration efficiencies between 44 and 95% depending on the chemical family of the substance. Compounds belonging to the following families have been detected in the samples: organic acids, alcohols, ketones, aldehydes, pyrazines, and reduced sulphur compounds, among others. Average total organic carbon removal efficiency was 88%, while NH3and H2S removal efficiencies were 88% and 87%, respectively, and odor concentration abatement was 78%.

scholarly journals Estimation of atmospheric total organic carbon (TOC) – paving the path towards carbon budget closure

2019 ◽  
Vol 19 (1) ◽  
pp. 459-471 ◽  
Author(s):  
Mingxi Yang ◽  
Zoë L. Fleming
Keyword(s):  
Carbon Dioxide ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Organic Compounds ◽  
Carbon Budget ◽  
Dimethyl Sulfide ◽  
Anthropogenic Activity ◽  
Heated Sample ◽  
Diurnal Variability ◽  
Marine Air

Abstract. The atmosphere contains a rich variety of reactive organic compounds, including gaseous volatile organic carbon (VOCs), carbonaceous aerosols, and other organic compounds at varying volatility. Here we present a novel and simple approach to measure atmospheric non-methane total organic carbon (TOC) based on catalytic oxidation of organics in bulk air to carbon dioxide. This method shows little sensitivity towards humidity and near 100 % oxidation efficiencies for all VOCs tested. We estimate a best-case hourly precision of 8 ppb C during times of low ambient variability in carbon dioxide, methane, and carbon monoxide (CO). As proof of concept of this approach, we show measurements of TOC+CO during August–September 2016 from a coastal city in the southwest United Kingdom. TOC+CO was substantially elevated during the day on weekdays (occasionally over 2 ppm C) as a result of local anthropogenic activity. On weekends and holidays, with a mean (standard error) of 102 (8) ppb C, TOC+CO was lower and showed much less diurnal variability. TOC+CO was significantly lower when winds were coming off the Atlantic Ocean than when winds were coming off land if we exclude the weekday daytime. By subtracting the estimated CO from TOC+CO, we constrain the mean (uncertainty) TOC in Atlantic-dominated air masses to be around 23 (±≥8) ppb C during this period. A proton-transfer-reaction mass spectrometer (PTR-MS) was deployed at the same time, detecting a large range of organic compounds (oxygenated VOCs, biogenic VOCs, aromatics, dimethyl sulfide). The total speciated VOCs from the PTR-MS, denoted here as Sum(VOC), amounted to a mean (uncertainty) of 12 (±≤3) ppb C in marine air. Possible contributions from a number of known organic compounds present in marine air that were not detected by the PTR-MS are assessed within the context of the TOC budget. Finally, we note that the use of a short, heated sample tube can improve the transmission of organics to the analyzer, while operating our system alternately with and without a particle filter should enable a better separation of semi-volatile and particulate organics from the VOCs within the TOC budget. Future concurrent measurements of TOC, CO, and a more comprehensive range of speciated VOCs would enable a better characterization and understanding of the atmospheric organic carbon budget.

scholarly journals Synthesis of Nanosilica from Padas Stone to Reduce The Total Organic Carbon of Palm Oil Waste

2019 ◽  
Vol 20 (1) ◽  
pp. 39
Author(s):  
Anis Shofiyani ◽  
Fara Chitra ◽  
Winda Rahmalia ◽  
R. Rudiyansyah ◽  
Andi Hairil Alimuddin
Keyword(s):  
Organic Carbon ◽  
Silicon Dioxide ◽  
Total Organic Carbon ◽  
Surface Area ◽  
Palm Oil ◽  
Sol Gel ◽  
Research Synthesis ◽  
Natural Mineral ◽  
Ftir Spectrophotometry ◽  
Microwave Assistance

Padas stone is one of the natural mineral containing 67.5% of SiO2 compounds. In this research, synthesis of nanosilica was carried out by sol-gel method asistanced by 2.45 GHz microwave radiations with low (10%), medium (50%) and high (100%) power at 30 and 60 minutes of contact times. It was analyzed by XRD, BET, FTIR spectrophotometry and SEM. The synthesized silica was then used as absorbent for total organic carbon (TOC) of palm oil waste. The results show that the synthesized silica was a mixture of cristobalite and quartz type minerals according to ICDD No. 00-003-0271 and 01-083-287. The surface area and silicon dioxide contains are 12.174 m2/g and 76.325% for silica without microwave assistance (SiO2-TPMW); 12.796 m2/gand 86.385% for silica with 30 minutes on 10% microwave assistance(SiO2 -MW 10A); 12.735 m2/gand 86.254% for silica with 60 minutes on 10% microwave assistance (MW 10B); 13,659 m2/gand 87.211% for MW 50A; 13,583 m2/g and 86.684% for MW 50B;7.883 m2/gand 57.527% for MW 100A; also 8.752 m2/g and 37.725% for MW 100B, respectively. The use of silica as an absorbent of TOC shows the effectiveness of 62.89% (TPMW); 63.68% (MW 10A); 62.96% (MW 10B); 65.25% (MW 50A); 64.61% (MW 50B); 62.37% (MW 100A) and 61.18% (MW 100B) from the initial TOC of 1520 mg/L. Keywords: synthesis, nanosilica, padas stone, total organic carbon, oil waste.

scholarly journals Estimation of atmospheric total organic carbon (TOC) – paving the path towards carbon budget closure

2018 ◽  
Author(s):  
Mingxi Yang ◽  
Zoë L. Fleming
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Organic Compounds ◽  
Carbon Budget ◽  
Dimethyl Sulfide ◽  
Proton Transfer Reaction ◽  
Anthropogenic Activity ◽  
Carbonaceous Aerosols ◽  
Diurnal Variability ◽  
Marine Air

Abstract. The atmosphere contains a rich variety of reactive organic compounds, including gaseous volatile organic carbon (VOCs), carbonaceous aerosols, and other organic compounds at varying volatility. Here we present measurements of atmospheric non-methane total organic carbon plus carbon monoxide (TOC+CO) during August-September 2016 from a coastal city in the southwest United Kingdom. TOC+CO was substantially elevated during the day on weekdays (occasionally over 2 ppm C) as a result of local anthropogenic activity. On weekends and holidays, with a mean (standard error) of 102 (8) ppb C, TOC+CO was lower and showed much less diurnal variability. Excluding weekday daytime, TOC+CO was significantly lower when winds were coming off the Atlantic Ocean than when winds were coming off land. By subtracting the estimated CO from TOC+CO, we constrain the mean (uncertainty) TOC in marine air to be around 19 (±≥8) ppb C during this period. A proton-transfer-reaction mass spectrometer (PTR-MS) was deployed at the same time, detecting a large range of organic compounds (oxygenated VOCs, biogenic VOCs, aromatics, dimethyl sulfide). The total speciated VOCs from the PTR-MS, denoted here as Sum(VOC), amounted to a mean (uncertainty) of 11(±≤3) ppb C in marine air. We assess the possible contributions from a number of known organic compounds present in marine air that were not detected by the PTR-MS. Future concurrent measurements of TOC, CO, and a more comprehensive range of speciated VOCs would enable a better characterization and understanding of atmospheric organic carbon budget.

Total Organic Carbon as an Index for Specification of Water for Injection

1987 ◽  
Vol 70 (4) ◽  
pp. 681-686
Author(s):  
Rieko Matsuda ◽  
Mumio Ishibashi ◽  
Mitsuru Uchiyama ◽  
Tamio Hiraoka ◽  
Haruhiko Hoshida ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Organic Compounds ◽  
Potassium Permanganate ◽  
Uv Spectroscopy ◽  
The Other ◽  
Model Compounds ◽  
Analysis Determination ◽  
Permanganate Consumption

Abstract Determination of organic compounds present as contaminants in purified water is of great importance. Total organic carbon (TOC) may be a useful parameter for evaluating the purity of water. This paper describes and compares the analytical results for solutions of 12 model compounds obtained by 3 methods: total organic carbon (TOC) analysis, determination of potassium permanganate consumption, and UV spectroscopy. TOC analysis gave values corresponding to the expected amounts of organic carbon for all the model compounds, whereas the other 2 methods gave highly variable results.

Universal HPLC Detector for Hydrophilic Organic Compounds by Means of Total Organic Carbon Detection

2018 ◽  
Vol 90 (11) ◽  
pp. 6461-6467 ◽  
Author(s):  
Shin-Ichi Ohira ◽  
Kyosuke Kaneda ◽  
Toru Matsuzaki ◽  
Shuta Mori ◽  
Masanobu Mori ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Organic Compounds ◽  
Carbon Detection ◽  
Hplc Detector

Treatment of 2,4-Dichlorophenol by Solar Photocatalysis: Comparison of Coupled Photocatalytic-Active Carbon vs. Active Carbon

2000 ◽  
Vol 123 (2) ◽  
pp. 138-142 ◽  
Author(s):  
Sixto Malato ◽  
Julia´n Blanco ◽  
Pilar Ferna´ndez-Iba´n˜ez ◽  
Julia Ca´ceres
Keyword(s):  
Organic Carbon ◽  
Solar Radiation ◽  
Total Organic Carbon ◽  
Active Carbon ◽  
Pilot Plant ◽  
Photocatalytic Oxidation ◽  
Practical Application ◽  
Carbon Adsorption ◽  
Pilot Plant Scale ◽  
Slow Kinetic

The photocatalytic oxidation of 2,4-Dichlorophenol (DCP), using TiO2 suspensions under solar radiation, has been studied at pilot-plant scale at the Plataforma Solar de Almerı´a (PSA). This compound is used as a model to demonstrate the practical application of the treatment. Total Organic Carbon (TOC) analysis is applied to confirm the total mineralization of the contaminants. The pilot plant has a volume of 247 L and consists of 9 m2 of CPC modules (with transparent tubes) connected to a recirculation tank. DCP at 20, 50 and 200 mg/L is completely photodegraded in the presence of 200 mg/L of TiO2, but mineralization is slow when organics concentration is small. The results obtained from these experiments have been used to decide the dimensions of a solar photocatalytic plant for treating wastewater contaminated with different concentration of DCP. Due to the slow kinetic obtained in the photodegradation last steps, a combination with GAC treatment is proposed. Besides, this article attempts to compare the advantages, disadvantages and costs of photocatalytic treatment, versus other more conventional technologies such as active carbon adsorption.

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