scholarly journals Optimization of Nano- Photocatalytic Reactor for Organophosphorus Degradation

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Ilin Sadeghi ◽  
Pooya Arbab ◽  
Mahdi Fathizadeh ◽  
Hoseen Fakhraee ◽  
Mahdi Amrollahi
Keyword(s):  
Reaction Rate ◽  
Ph Value ◽  
Lag Time ◽  
Complete Oxidation ◽  
Triethyl Phosphate ◽  
Kinetic Reaction ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Kinetic Order ◽  
Complete Degradation

The photocatalytic decontamination of triethyl phosphate (TEP) is studied by the UV/nano-TiO2process. The nano-TiO2concentration and pH value for the complete oxidation of TEP were investigated in different concentrations of TEP. The kinetic reaction was calculated for TEP as a function of initial concentration of TEP. Results of adsorptions showed that TEP was adsorbed better in alkalinity pH, and the natural pH had the highest reaction rate for complete degradation. Also, the zero-kinetic order with the lag time as a function of initial concentration of TEP and TiO2was suggested for oxidation of TEP. The optimized concentration of nano-TiO2was 400 mg/lit which had the best conversion and the lowest lag time in the reaction.

Studies on SiO2/TiO2 Complex Film of the Filter Material Carrier and its Photocatalytic Features

2011 ◽  
Vol 340 ◽  
pp. 293-299
Author(s):  
Wen Yi Zhang ◽  
Ning Han ◽  
Li Rong Yao ◽  
Pei Cheng Fan ◽  
Rong Chen
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Ph Value ◽  
Influence Factors ◽  
Methyl Orange Solution ◽  
Filter Material ◽  
Major Influence ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Complex Film

The nano-SiO2/TiO2complex film was used to implement modification of the surface on the sintered filter material of coal refuse. In the photocatalytic reactor, methyl orange was taken as the response substrate to test the photocatalytic activity and the influence of the different Si/Ti ratios of the complex film on the photocatalytic activity of modified filter material. The Langmuir-Hinshelwood dynamics model was applied to describe the dynamic process during which multiphase photocatalytic modified filter material disassembled the methyl orange. The results indicated that the initial concentration, pH value, aeration illumination condition and the Si/Ti ratios of the complex film were the major influence factors of the efficiency of photocatalytic degeneration. In the acidic environment, and on the illumination and aeration conditions, when the initial concentration of the methyl orange solution was 6mg/L and the Si/Ti ratio was 1/39, the SiO2/TiO2complex film was used to decolor the methyl orange, then the decolorization rate was over 99.8% after 2h.

Preparation of Sands Modified by Aluminous Salt and its Adsorption Capability of CD2+

2011 ◽  
Vol 130-134 ◽  
pp. 856-859
Author(s):  
Chun Sheng Ding ◽  
Yang Ping Fu ◽  
Qian Fen Zhu ◽  
Jing Fu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Influencing Factors ◽  
Removal Efficiency ◽  
Specific Surface Area ◽  
Quartz Sand ◽  
Ph Value ◽  
Alkaline Condition ◽  
Initial Concentration ◽  
Adsorption Capability

In this experiment quartz sand was chosen as a carrier to be coated by aluminous salt under alkaline condition, and then the specific surface area was tested, and the adsorption capability and Cd2+ removal influencing factors of modified sand were studied. The investigation results showed that the specific surface area of modified sand was 75.244m2/g which was 9.38 times of that of original sand; the removal efficiency of Cd2+ by aluminous salt modified sand reached 59% contrast to 39% of original sand with pH 7.00. It was also found that the removal efficiency of Cd2+ by the aluminous salt modified sand was reduced with the increase of initial concentration of Cd2+ solution, and was enhanced with the increase of pH value, the Cd2+ removal efficiency was almost 71% with pH 9.0.

Study on Decolorization of Wastewater Containing Acid Orange II by Adsorption on Expanded Graphite

2011 ◽  
Vol 183-185 ◽  
pp. 873-876
Author(s):  
Jun Jie Yue ◽  
Xing Long Jin ◽  
Zhao Hui Jin
Keyword(s):  
Ph Value ◽  
Expanded Graphite ◽  
Orange Ii ◽  
Dye Wastewater ◽  
Temperature Level ◽  
Initial Concentration ◽  
Acid Orange ◽  
Ph Values ◽  
Simulated Wastewater ◽  
Acid Orange Ii

In this paper, the adsorption and decolorization capability of expanded graphite (EG) on the simulated wastewater containing Acid Orange Ⅱwere studied. The experimental results show that the initial concentration of wastewater, the dosage of EG, the pH value and the temperature all have greater effects on the decolorization ratio of simulated Acid Orange Ⅱ wastewater. The dye- wastewater containing lower concentration(＜150 mg/L) of Acid Orange Ⅱ is more suitable to be treated by EG, and approximately 100 mg/L is the preferable concentration. The decolorization ratio increases with the increment of the dosage of EG and the temperature level, but the growth rate obviously decreases at the higher initial concentration. All the decolorization ratios under strong acidic (pH<5) and alkalic (pH>11) conditions are higher than that at the range of 5-11 pH values, the highest value even reaches over 94%, while the decolorization ratio under the latter conditions are only between 75% and 85%.

THE CATALYTIC OXIDATION OF ETHYLENE TO ETHYLENE OXIDE

1949 ◽  
Vol 27b (11) ◽  
pp. 813-827 ◽  
Author(s):  
F. L. W. McKim ◽  
A. Cambron
Keyword(s):  
Ethylene Oxide ◽  
Catalytic Oxidation ◽  
Atmospheric Pressure ◽  
Reaction Rate ◽  
Ethylene Dichloride ◽  
Complete Oxidation ◽  
Large Excess ◽  
Ethylene Concentration ◽  
Silver Catalysts ◽  
Flow Experiments

The catalytic oxidation of ethylene to ethylene oxide was investigated in flow experiments over silver catalysts at atmospheric pressure between 260° and 350 °C. Calcium oxalate and stannous oxide were used as catalyst promoters. Close temperature control was provided by mounting the catalyst on a silver support. At 270 °C. the selectivity increased from about 25%, with ethylene in large excess, to about 55%, with oxygen in large excess. With air constant and in large excess, the over-all reaction rate was found to be proportional to the square root of the ethylene concentration. With ethylene constant and in large excess, the reaction rate was found to be roughly proportional to the oxygen concentration. The presence of methane, ethane, or propane promoted the complete oxidation of ethylene to carbon dioxide and water. In the absence of paraffins the addition of traces of ethylene dichloride only served to poison the catalyst.

scholarly journals Degradation of methylene blue by natural manganese oxides: kinetics and transformation products

2019 ◽  
Vol 6 (7) ◽  
pp. 190351 ◽  
Author(s):  
Shuangxi Zhou ◽  
Zhiling Du ◽  
Xiuwen Li ◽  
Yunhai Zhang ◽  
Yide He ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Manganese Oxides ◽  
Ph Value ◽  
Low Cost ◽  
Reaction System ◽  
Transformation Products ◽  
Low Ph ◽  
Initial Concentration ◽  
Environmental Material ◽  
High Redox Potential

In this study, natural manganese oxides (MnO x ), an environmental material with high redox potential, were used as a promising low-cost oxidant to degrade the widely used dyestuff methylene blue (MB) in aqueous solution. Although the surface area of MnO x was only 7.17 m 2 g −1 , it performed well in the degradation of MB with a removal percentage of 85.6% at pH 4. It was found that MB was chemically degraded in a low-pH reaction system and the degradation efficiency correlated negatively with the pH value (4–8) and initial concentration of MB (10–50 mg l −1 ), but positively with the dosage of MnO x (1–5 g l −1 ). The degradation of MB fitted well with the second-order kinetics. Mathematical models were also built for the correlation of the kinetic constants with the pH value, the initial concentration of MB and the dosage of MnO x . Furthermore, several transformation products of MB were identified with HPLC-MS, which was linked with the bond energy theory to reveal that the degradation was initiated with demethylation.

Kinetics of the oxidation of diphenyl sulfide with hydrogen peroxide catalyzed by sodium metavanadate

1982 ◽  
Vol 60 (7) ◽  
pp. 848-852 ◽  
Author(s):  
Yoshiro Ogata ◽  
Kazushige Tanaka
Keyword(s):  
Hydrogen Peroxide ◽  
Rate Constant ◽  
Reaction Rate ◽  
Catalytic Amount ◽  
Probable Mechanism ◽  
Initial Concentration ◽  
Sodium Metavanadate ◽  
Low Concentration ◽  
Diphenyl Sulfide ◽  
Kinetics Of

The oxidation of diphenyl sulfide (Ph2S) by hydrogen peroxide in the presence of a catalytic amount of sodium metavanadate (NaVO3) has been studied kinetically by means of iodometry of hydrogen peroxide. The reaction rate is expressed as: v = k[NaVO3]st[Ph2S]2, when the concentration of catalyst is very low and [Ph2S]0/[H2O2]0 > 2, where []st and []0 mean stoichiometric and initial concentration, respectively. The effective oxidant may consist of polymeric as well as monomeric peroxyvanadate in view of the effect of concentration of catalyst on the rate. The main oxidizing species at low concentration of catalyst seems to be diperoxyvanadate VO5−. The rate constant k2 in v = k2[Ph2S]2 tends to decrease with initial concentration of H2O2, which is present in excess of the catalyst. A probable mechanism for the oxidation is discussed.

Nanoparticle Fe3O4 magnetized activated carbon from Armeniaca sibirica shell for the adsorption of Hg(II) ions

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 6100-6120
Author(s):  
Yinan Hao ◽  
Yanfei Pan ◽  
Qingwei Du ◽  
Xudong Li ◽  
Ximing Wang
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Ph Value ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Entropy Change ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Initial Concentration

Armeniaca sibirica shell activated carbon (ASSAC) magnetized by nanoparticle Fe3O4 prepared from Armeniaca sibirica shell was investigated to determine its adsorption for Hg2+ from wastewater. Fe3O4/ASSAC was characterized using XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), and BET (Brunauer–Emmett–Teller). Optimum adsorption parameters were determined based on the initial concentration of Hg2+, reaction time, reaction temperature, and pH value in adsorption studies. The experiment results demonstrated that the specific surface area of ASSAC decreased after magnetization; however the adsorption capacity and removal rate of Hg2+ increased 0.656 mg/g and 0.630%, respectively. When the initial concentration of Hg2+ solution was 250 mg/L and the pH value was 2, the adsorption time was 180 min and the temperature was 30 °C, and with the Fe3O4/ASSAC at 0.05 g, the adsorption reaching 97.1 mg/g, and the removal efficiency was 99.6%. The adsorption capacity of Fe3O4/ASSAC to Hg2+ was in accord with Freundlich isotherm models, and a pseudo-second-order kinetic equation was used to fit the adsorption best. The Gibbs free energy ΔGo < 0，enthalpy change ΔHo < 0, and entropy change ΔSo < 0 which manifested the adsorption was a spontaneous and exothermic process.

Amidoxime Functionalized Mesoporous SBA-15 with Various Mesostructures for Highly Efficient Concentration of U(VI)

NANO ◽  
2019 ◽  
Vol 14 (02) ◽  
pp. 1950027
Author(s):  
Ziyan Yang ◽  
Xiaoli Yang ◽  
Rui Hu ◽  
Junfeng Wu
Keyword(s):  
Surface Chemistry ◽  
Aqueous Solutions ◽  
Contact Time ◽  
High Selectivity ◽  
Ph Value ◽  
Sorption Kinetics ◽  
Initial Concentration ◽  
Geochemical Conditions ◽  
Pore Length ◽  
Ordered Mesoporous

Many current sorbents are limited for U(VI) concentration from aqueous solutions due to their inappropriate structures and surface chemistry. Herein, we report the rapid sorption of U(VI) with high capacities and selectivity by amidoxime modified ordered mesoporous SBA-15 with two typical morphologies (i.e., rods and plates) via a post-grafting method. Variables of the geochemical conditions (contact time, pH value, initial concentration, temperature and coexisting metal ions) are investigated. The results show that the mesostructures including morphologies and pore length of SBA-15 perform the dominant function for the fast sorption kinetics (10[Formula: see text]min for plates, 20[Formula: see text]min for rods), while the modified amidoxime groups make the excellent U(VI) sorption capacities (646.2[Formula: see text]mg[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] for plates, 499.8[Formula: see text]mg[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] for rods at pH 5.0 and [Formula: see text] 298.15[Formula: see text]K) and high selectivity possible. U(VI) adsorbed amidoxime-functionalized SBA can also be effectively regenerated by HCl solutions and reused well after six cycles.

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