scholarly journals The Oxidation Mechanism of Aniline by Ozone Water and Ozone Micro-nano Bubble Water and Its Influencing Factors

2022 ◽  
Author(s):  
Zeming Xie ◽  
Jiali Shentu ◽  
Yuyang Long ◽  
Li Lu ◽  
Dongsheng Shen ◽  
...  
Keyword(s):  
Treatment Process ◽  
Mass Transfer Rate ◽  
Oxidation Mechanism ◽  
Utilization Rate ◽  
Groundwater Treatment ◽  
Direct Oxidation ◽  
Negative Effect ◽  
Aniline Oxidation ◽  
Oxidation Efficiency ◽  
Oxidation Effect

Abstract Aniline is a kind of refractory contaminant that is difficult to be degraded by microorganisms. Ozone is a green and efficient reagent to oxidize aniline, while the ozone oxidation efficiency is restricted by the low ozone mass transfer rate. Micro-nano bubble ozonation has been developed as a new method to significantly improve the ozone utilization rate, while the characteristics of ozone micro-nano bubble when compared with dissolved ozone is not clear. The paper carried out batch experiments to research the oxidation effect of aniline by ozone water (OW) and ozone micro-nano bubble water (OMNBW), and found that the degradation rate of aniline by OMNBW was 2.8~5.9% higher than that by OW. The increase of pH had a negative effect on the degradation of aniline by OW and OMNBW. SO42-, Cl-, HCO­3- and Mg2+ could inhibit the degradation efficiency by 0.04%, 0.99%, 0.44% and 10.4% for OW, while the ratios were 1.1%, 6.4%, 4.1% and 1.5% for OMNBW. The addition of humic acid and fulvic acid could decrease the oxidation rate of aniline by 35% and 49% for OW, while the ratios were 41% and 62% for OMNBW. Through quenching experiment, it was found that the direct oxidation by ozone molecules and the indirect oxidation by superoxide radicals were main pathways for aniline oxidation by OW and OMNBW. This work provided a practical guide for the application of OMNBW in wastewater and groundwater treatment process.

scholarly journals A facile and effective method for preparation of 2.5-furandicarboxylic acid via hydrogen peroxide direct oxidation of 5-hydroxymethylfurfural

2017 ◽  
Vol 19 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Shuang Zhang ◽  
Long Zhang
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Oxidation Mechanism ◽  
Molar Ratio ◽  
Alkaline Condition ◽  
Optimal Parameters ◽  
Direct Oxidation ◽  
Reaction Parameters ◽  
Alkaline Conditions ◽  
Furandicarboxylic Acid

Abstract In this paper, 2,5-furandicarboxylic acid (FDCA) was efficiently prepared by the direct oxidation of 5-hydroxymethylfurfural (5-HMF) using hydrogen peroxide (H2O2) in alkaline conditions without any catalysts. The effects of reaction parameters on the process were systematically investigated and the optimal parameters were obtained as follows: molar ratio of 5-HMF:KOH:H2O2 was 1:4:8, reaction temperature and reaction time were determined as 70°C and 15 minutes, respectively. Under these conditions, the yield of FDCA was 55.6% and the purity of FDCA could reach 99%. Moreover, we have speculated the detailed oxidation mechanism of 5-HMF assisted by hydrogen peroxide in alkaline condition to synthesize FDCA.

Effect of Phenol on Treatment of Sewage from Channel Discharge with Biological Accelerator-Biofilm Process

2011 ◽  
Vol 243-249 ◽  
pp. 3761-3764
Author(s):  
Gai Mei Guo
Keyword(s):  
Treatment Process ◽  
Sewage Treatment ◽  
Ammonia Nitrogen ◽  
Removal Rates ◽  
Promotion Effect ◽  
Initial Concentration ◽  
Research Results ◽  
Negative Effect ◽  
Biofilm Process

The research studied enhanced treatment of sewage from discharging points of rivers by biofilm process dosing with enzyme and the effect of phenol on removal rates of the main pollution indexes, and investigated promotion effect of enzyme (including the laboratory developed compounded enzyme and the foreign composite enzyme) on treatment of sewage by biofilm process. The research results indicated that when initial concentration of phenol was 5mg/L, the removal rates of phenol, CODCrand ammonia nitrogen obviously decreased compared to no phenol added to reactor A, B and C, and the negative effect of phenol was smaller on reactor B and C than on reactor A. Moreover, enzyme had good promotion effect on biofilm process during the sewage treatment process.

Factors Affecting Mercury Oxidation by SCR Catalysts

2014 ◽  
Vol 986-987 ◽  
pp. 755-760
Author(s):  
Wen Du ◽  
Li Bao Yin ◽  
Yu Qun Zhuo ◽  
Qi Sheng Xu ◽  
Liang Zhang ◽  
...  
Keyword(s):  
Active Sites ◽  
Catalytic Reduction ◽  
Space Velocity ◽  
Injection Rate ◽  
Mercury Oxidation ◽  
Factors Affecting ◽  
Scr Catalysts ◽  
Negative Effect ◽  
Oxidation Efficiency ◽  
Scr System

The application of selective catalytic reduction (SCR) system may affect mercury speciation in coal-combustion flue gas. The factors affecting mercury oxidation efficiency by SCR catalysts have been evaluated in this research. The influencing factors investigated included hydrogen chloride (HCl), sulfur dioxide (SO2), ammonia (NH3) injection rate and space velocity. HCl had been found to promote mercury oxidation significantly. The Eley-Rideal mechanism was proven to be suitable to explain the reaction of Hg0 and HCl. NH3 injection had a strong negative effect to mercury oxidation. The deactivation of aged SCR catalysts was mainly due to loss of active sites.

Efficient photocatalytic defluorination of perfluorooctanoic acid over BiOCl nanosheets via a hole direct oxidation mechanism

2017 ◽  
Vol 317 ◽  
pp. 925-934 ◽  
Author(s):  
Zhou Song ◽  
Xuelin Dong ◽  
Nan Wang ◽  
Lihua Zhu ◽  
Zhihong Luo ◽  
...  
Keyword(s):  
Oxidation Mechanism ◽  
Perfluorooctanoic Acid ◽  
Direct Oxidation

Mass transfer rate from gas bubbles into liquid in presence of solid particles with strong adsorbing properties

1989 ◽  
Vol 54 (11) ◽  
pp. 3061-3068 ◽  
Author(s):  
Jan Kratochvíl ◽  
František Kaštánek
Keyword(s):  
Mass Transfer ◽  
Active Carbon ◽  
Mass Transfer Rate ◽  
Solid Particles ◽  
Pure Liquid ◽  
Carbon Particles ◽  
Carbon Soot ◽  
Negative Effect ◽  
Liquid Mass Transfer ◽  
Positive Effect

The presence of small particles with adsorbing activity (carbon soot, active carbon etc.) in the bubble bed augments the gas-liquid mass transfer coefficient kLa about approximately 20% in comparison with pure liquid. This fact can be explained by penetrating and disturbance effect of particles into the boundary layer of liquid near the interface. This activity is however reduced to small concentrations of particles (0.07% mass in the case of carbon soot, 0.5%-1.0% mass for active carbon particles). Addition of small amount of particles with adsorbing activity to the liquids containing superficial active agents (tensides) can partially overcome the negative effect of tensides on kLa value. The positive effect of particles of active carbon on kLa in bubble beds is less pronounced than that published for the case of mechanically agitated vessels.

scholarly journals Knowledge, Attitude and Utilization of Entrepreneurship Programmes by Students in Cross River State College of Health Technology, Calabar, Nigeria

2021 ◽  
pp. 1-9
Author(s):  
G. A. Ugal ◽  
A. J. Adie ◽  
J. Ekpe Osim
Keyword(s):  
Utilization Rate ◽  
Sustainable Business ◽  
Chi Square ◽  
Statistical Tool ◽  
Cross River State ◽  
State College ◽  
Negative Effect ◽  
Level Of Significance ◽  
Higher Institutions ◽  
Collaborative Efforts

The key objective of entrepreneurship education in higher institutions generally is to foster a culture amongst students with a view of not only educating them but to also support graduates towards establishing and also maintaining sustainable business ventures. To achieve the purpose of this study, the basic structures and three research objectives, questions and hypotheses were formulated. A well designed questionnaire was prepared, two hundred and sixty copies printed and distributed to respondents. Two hundred and fifty - five (255) copies (of the questionnaire) were returned, representing 98% success, while five (5) copies were destroyed for want of information and poor completion. The two hundred and fifty – five copies were used for analysis. The data were extracted from the questionnaire and arranged in tables to ease percentage analysis. Chi – square statistical tool was used to test the hypotheses at 0.05 level of significance. The result revealed that entrepreneurial education is relevant to students in the institution as it equipped them with skills for post-graduation job creation ability, the students’ low attitude towards the scheme which seems to have negative effect on the utilization rate. The study recommended collaborative efforts of Government to identify other entrepreneurship programmes to address unemployment on graduation.

High-Temperature Oxidation Behavior of Fe-Si-Ce Alloys

2016 ◽  
Vol 35 (2) ◽  
pp. 177-183 ◽  
Author(s):  
Yong Su ◽  
Shunke Zhang ◽  
Guangyan Fu ◽  
Qun Liu ◽  
Yuanze Tang
Keyword(s):  
Grain Size ◽  
Oxidation Behavior ◽  
Oxidation Mechanism ◽  
Mass Gain ◽  
Optical Microscope ◽  
Oxide Scales ◽  
Temperature Oxidation ◽  
Beneficial Effects ◽  
Negative Effect ◽  
High Temperature Oxidation Behavior

AbstractThe oxidation behavior of Fe-Si-Ce alloys with different Ce content at 1,173 and 1,273 K has been studied by means of optical microscope (OM), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM). Results show that the Ce addition refines the grain size of Fe-Si alloys, and correspondingly the grain size of the oxides decreases, which increases the grain boundary concentration and promotes the short-path diffusion of the alloying elements and oxygen. During oxidation, the positive effect of the grain refinement on the oxidation behavior of the alloy is more obvious than negative effect, so the Ce addition improves the oxidation resistances of the Fe-3Si alloys. Compared to Fe-3Si-0.5Ce alloy, Fe-3Si-5.0Ce alloy has the larger mass gain for the preferential oxidation of the excessive content of Ce exceeding its beneficial effects. The rare earth Ce changes the oxidation mechanism of Fe-Si alloys. Oxygen penetrates the oxide scales and reacts preferentially with Ce-rich phases, which results in the pinning effect and improves the adhesion of the oxide scales.

Enhanced oxidation of MgSO3 during desulfurization by a novel spray method in magnesium-based seawater exhaust gas clean system

2017 ◽  
Vol 231 (4) ◽  
pp. 871-876
Author(s):  
Quan Liu ◽  
Meijun Sun ◽  
Tianliang Zhang ◽  
Yimin Zhu
Keyword(s):  
Oxidation Rate ◽  
Oxidation Mechanism ◽  
Aeration Tank ◽  
Exhaust Gas ◽  
Oxidation Method ◽  
Marine Diesel ◽  
Clean System ◽  
Desulfurization Process ◽  
Oxidation Efficiency ◽  
The Cost

The magnesium-based seawater exhaust gas clean system is effective in reducing sulfur dioxide emission from marine diesel engines. Oxidation of the desulfurization by-product, magnesium sulfite (MgSO3), is required for recycling. However, the oxidation efficiency is generally low in the aeration tank after the desulfurization process, making the tank volume too large for practical use on ocean vessels. In this article, we propose a novel spray oxidation method to enhance the oxidation of MgSO3 during the desulfurization process. The effects of MgSO3 content, pH and temperature on the oxidation rate were investigated. The results showed that the spray oxidation rate of MgSO3 was 1.5 order with respect to the MgSO3 concentration under both unsaturated and saturated conditions of MgSO3 solution, which is different from the aeration oxidation researches. The spray oxidation rate decreased with the increase in pH and raised slowly as the temperature increased. The MgSO3 oxidation mechanism of the spray oxidation method was analyzed and discussed in comparison with the traditional bubble aeration method. The novel spray oxidation method is effective in reducing the cost of the subsequent MgSO3 aeration oxidation process and the offprint of aeration tanks, thus is promising to be applied on ocean vessels.

Do hospital mergers increase hospital efficiency? Evidence from a National Health Service country

2007 ◽  
Vol 12 (4) ◽  
pp. 230-235 ◽  
Author(s):  
Lars Kjekshus ◽  
Terje Hagen
Keyword(s):  
Data Envelopment Analysis ◽  
Technical Efficiency ◽  
Cost Efficiency ◽  
Treatment Process ◽  
Panel Data Analysis ◽  
Data Envelopment ◽  
Hospital Mergers ◽  
Positive Effects ◽  
Negative Effect ◽  
Using Data

Objectives: To analyse the effects on technical and cost efficiency of seven hospital mergers over the period 1992–2000 in Norway. The mergers involved 17 hospitals. Methods: First, efficiency scores were generated using Data Envelopment Analysis for 53 merged and non-merged hospitals over the nine years. Second, the effect of mergers was estimated through panel data analysis. Results: In general, the mergers showed no significant effect on technical efficiency and a significant negative effect of 2–2.8% on cost efficiency. However, positive effects on both cost and technical efficiency were found in one merger where more hospitals were involved, and where administration and acute services were centralized. Conclusion: The findings indicate that large mergers involving radical restructuring of the treatment process may improve efficiency as intended, but most mergers do not.

Sign in / Sign up

Export Citation Format

Share Document