scholarly journals Degradation of BTEX in groundwater by nano-CaO2 particles activated with L-cysteine chelated Fe(III): enhancing or inhibiting hydroxyl radicals generation

2021 ◽  
Author(s):  
Xuecheng Sun ◽  
Meesam Ali ◽  
Changzheng Cui ◽  
Shuguang Lyu
Keyword(s):  
Hydroxyl Radicals ◽  
Experimental Results ◽  
Molar Ratio ◽  
Ultrapure Water ◽  
Ferric Ions ◽  
Calcium Peroxide ◽  
Redox Cycles ◽  
Simultaneous Oxidation ◽  
Oxidation Performance ◽  
Benzene Toluene

Abstract The simultaneous oxidation performance of benzene, toluene, ethylbenzene, and xylene (BTEX) by nanoscale calcium peroxide particles (nCaO2) activated with ferric ions (Fe(III)) and the mechanism of the enhancement of BTEX degradation by L-cysteine (L-cys) were investigated. The batch experimental results showed that the nCaO2/Fe(III)/L-cys process was effective in the destruction of BTEX in both ultrapure water and actual groundwater. A proper amount of L-cys could enhance BTEX degradation due to the promotion of Fe(II)/Fe(III) redox cycles by the participation of L-cys, but excessive presence of L-cys would cause inhibition. Adding 1.0 mM L-cys to the nCaO2/Fe(III) system, the concentration of Fe(II) increased to 1.15 mM instantly. Simultaneously, the yield of HO• produced by 1.0 mM L-cys-containing system was 0.066 mM at 180 min reaction, higher than that without L-cys (0.049 mM). When excess L-cys (5.0 mM) was added to the system, the amount of Fe(II) increased to 3.73 mM because excessive L-cys caused a large number of Fe(III) in the system to be reduced. However, the yield of HO• decreased to 0.043 mM since excessive Fe(II) could conversely scavenge HO• to produce Fe(III) again. EPR tests and quenching results indicated that HO• was the dominant reactive species in the nCaO2/Fe(III)/L-cys system. For the removal of BTEX, the optimal molar ratio of nCaO2/Fe(III)/L-cys was 10.5/20/1 based on the calculation by RSM. Finally, the BTEX destruction pathway was proposed according to the detected intermediates by LC-MS.

Proposal of a Novel Blanket System Using LiF-BeF2-LiI for a Fusion Reactor

2013 ◽  
Author(s):  
Hiroki Shishido ◽  
Youngmin Han ◽  
Kentaro Matsui ◽  
Noritaka Yusa ◽  
Hidetoshi Hashizume
Keyword(s):  
Monte Carlo ◽  
Melting Point ◽  
Numerical Simulations ◽  
Molten Salt ◽  
Fusion Reactor ◽  
Experimental Results ◽  
Molar Ratio ◽  
Data Library ◽  
Measured Density

This study proposes LiF-BeF2-LiI as a molten salt for a liquid blanket system of a fusion reactor. Firstly, the melting point of LiF-BeF2-LiI is measured as a function of the molar ratio of LiI. The experimental results confirmed that the melting point decreases to 398.2 °C when LiF:BeF2:LiI = 19:9.5:71.5, which is consistent with an earlier report. Experiments to evaluate the density and viscosity of LiF-BeF2-LiI are also carried out. The experiments revealed that the density of LiF-BeF2-LiI increases with the molar ratio of LiI, and the viscosity of LiF-BeF2-LiI (LiF:BeF2:LiI = 2:1:1) is somewhat larger than that of LiF-BeF2 (LiF:BeF2 = 2:1) but much smaller than that of LiF-BeF2 (LiF:BeF2 = 3:2). Monte Carlo numerical simulations using MVP-2.0 with JENDL-4.0 data library are conducted on the basis of the measured density to discuss the feasibility of a blanket system using LiF-BeF2-LiI. The numerical simulations demonstrate that LiF-BeF2-LiI can realize TBR>1.4, which is required for a fusion blanket system, with Be pebble layer and enriching 6Li.

Chemical Dosimetry in the “Water Window”: Ferric Ions and Hydroxyl Radicals Produced by Intense Soft X Rays

2020 ◽  
Vol 193 (4) ◽  
pp. 372
Author(s):  
Luděk Vyšín ◽  
Przemysław Wachulak ◽  
Martina Toufarová ◽  
Nikita Medvedev ◽  
Roman A. Voronkov ◽  
...  
Keyword(s):  
Hydroxyl Radicals ◽  
X Rays ◽  
Ferric Ions ◽  
Water Window ◽  
Chemical Dosimetry

Effect of the Adjuvants on the Properties of Superfine SnO2 Powders

2018 ◽  
Vol 934 ◽  
pp. 35-40
Author(s):  
Jie Guang Song ◽  
Cai Liang Pang ◽  
Yue Liu ◽  
Jia Zhang ◽  
Lin Chen ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Solar Cells ◽  
Reaction Time ◽  
Powder Material ◽  
Tin Oxide ◽  
Experimental Results ◽  
Molar Ratio ◽  
New Type ◽  
Holding Temperature

Ultrafine SnO2 is a new type of material, in the field of solar cells and semiconductors have a lot of use. To get different morphology and different properties of tin oxide powder material, making more applications in the field, the effect of the adjuvants on the properties of superfine SnO2 powders were distigated. Through the analysis of experimental results, the conclusions are shown the stronger the alkalinity of the auxiliary agent, the larger the grain size of the obtained particles and the more uniform the particles. When the molar ratio of salt to alkali is more than 1: 4, the amount of alkali is gradually reduced, the particle size is small, the morphology is not uniform and easy to agglomerate. When the molar ratio of salt to alkali is 1: 4, the smaller particle size is shown, the appearance morphology is uneven. The longer the reaction time, the more complete the grain, the more uniform the morphology. Under the condition of SnCl4 concentration of 0.05 mol/L, reaction time is 4 days, salt and alkali molar ratio is 1: 4, holding temperature is 200 °C, the auxiliary agent is NaOH, the size, shape and properties of synthesized SnO2 are the better.

The Research on Preparation and Application of a Silicon-Based Efficient Coagulant

2011 ◽  
Vol 295-297 ◽  
pp. 543-546
Author(s):  
Jiao Jiao Wang ◽  
Chun Ying Han ◽  
Li Dan Zhang
Keyword(s):  
Industrial Wastewater ◽  
Experimental Results ◽  
Good Stability ◽  
Molar Ratio ◽  
Good Effect ◽  
Activation Time ◽  
Preparation Conditions ◽  
Silicon Based

In this paper, research was focused on the synthesis of a new efficient coagulant, boron -containing poly-silicate zinc (PSZB).The effect of the SiO2 concentration, Zn/Si molar ratio, B/Si molar ratio, activation time on flocculation properties were examined in detail. And the optimal preparation conditions were determined. At the same time, the industrial wastewater and life wastewater were treated for the properties test. The experimental results showed that the flocculant had good stability and good effect. It is a kind of good performance of flocculants.

Rich surface Co(iii) ions-enhanced Co nanocatalyst benzene/toluene oxidation performance derived from CoIICoIIIlayered double hydroxide

Nanoscale ◽  
2016 ◽  
Vol 8 (34) ◽  
pp. 15763-15773 ◽  
Author(s):  
Shengpeng Mo ◽  
Shuangde Li ◽  
Jiaqi Li ◽  
Yuzhou Deng ◽  
Shengpan Peng ◽  
...  
Keyword(s):  
Toluene Oxidation ◽  
Oxidation Performance ◽  
Benzene Toluene ◽  
Double Hydroxide

Application of Ozone in the Treatment of Nitric Oxide from Simulated Flue Gas

2013 ◽  
Vol 838-841 ◽  
pp. 2663-2666
Author(s):  
Xu Jie Lu
Keyword(s):  
Nitric Oxide ◽  
Removal Efficiency ◽  
Reaction Temperature ◽  
Flue Gas ◽  
Experimental Results ◽  
Molar Ratio ◽  
No Removal ◽  
Operating Condition ◽  
Molar Ratios

The objective of this work was to study the effect of some operating condition on the removal of NO from simulated flue gas in the lab-scale agitated bubbling reactor. The experimental results showed that NO removal efficiency went up with the increase in the molar ratios of O3/NO and the NO removal efficiency reached 92% at 3 of molar ratio. It can also be found that the average removal efficiency was slightly affected by the reaction temperature and almost retained over 75%.

scholarly journals Characterization, Dissolution, and Solubility of Lead Hydroxypyromorphite [Pb5(PO4)3OH] at 25–45°C

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Yinian Zhu ◽  
Zongqiang Zhu ◽  
Xin Zhao ◽  
Yanpeng Liang ◽  
Yanhua Huang
Keyword(s):  
Molar Ratio ◽  
Stoichiometric Ratio ◽  
Ultrapure Water ◽  
Solution Ph ◽  
Free Energy Of Formation ◽  
Initial Ph ◽  
Naoh Solution ◽  
Water Ph ◽  
Ft Ir ◽  
Sem Analyses

Dissolution of the hydroxypyromorphite [lead hydroxyapatite, Pb5(PO4)3OH] in HNO3solution (pH = 2.00), ultrapure water (pH = 5.60), and NaOH solution (pH = 9.00) was experimentally studied at 25°C, 35°C, and 45°C. The XRD, FT-IR, and FE-SEM analyses indicated that the hydroxypyromorphite solids were observed to have indistinguishable change during dissolution. For the hydroxypyromorphite dissolution in aqueous acidic media at initial pH 2.00 and 25°C, the aqueous phosphate concentrations rose quickly and reached the peak values after 1 h dissolution, while the aqueous lead concentrations rose slowly and reached the peak values after 1440 h. The solution Pb/P molar ratio increased constantly from 1.10 to 1.65 near the stoichiometric ratio of 1.67 to 209.85~597.72 and then decreased to 74.76~237.26 for the dissolution at initial pH 2.00 and 25°C~45°C. The averageKspvalues for Pb5(PO4)3OH were determined to be 10−80.77(10−80.57−10−80.96) at 25°C, 10−80.65(10−80.38−10−80.99) at 35°C, and 10−79.96(10−79.38−10−80.71) at 45°C. From the obtained solubility data for the dissolution at initial pH 2.00 and 25°C, the Gibbs free energy of formation [ΔGfo] for Pb5(PO4)3OH was calculated to be −3796.71 kJ/mol (−3795.55~−3797.78 kJ/mol).

scholarly journals Degradation of Trichloroethylene in Groundwater Using Iron Catalyzed Calcium Peroxide Systems

2020 ◽  
Vol 143 ◽  
pp. 02046
Author(s):  
Kegang Zhang ◽  
Xiaodong Wang ◽  
Xiaohui Zhang ◽  
Shengjie Peng
Keyword(s):  
Removal Efficiency ◽  
Sodium Citrate ◽  
Chemical Oxidation ◽  
Ferrous Ion ◽  
Contaminated Sites ◽  
Molar Ratio ◽  
Promising Technique ◽  
Calcium Peroxide ◽  
In Situ Chemical Oxidation

The application of calcium peroxide (CaO2) activated with ferrous ion chelate sodium citrate （TCD）to stimulate the degradation of trichloroethylene (TCE) was investigated. The experimental results show that the removal efficiency of TCE increases first and then decreases with the increase of CaO2 and Na2S2O8 dosage; the chelation ratio of Fe(II)/TCD, too much or too little, will affect the removal efficiency of TCE; when the molar ratio of CaO2/ Fe(II)/ TCD/ TCE is 18/6/6/1, the removal efficiency of TCE is the highest, reaching 97.99% within 200Min. The results demonstrated that the technique of CaO2 activated with ferrous ion is a highly promising technique in in situ chemical oxidation (ISCO) remediation in TCE contaminated sites.

scholarly journals Dual function adsorbent-catalyst CuO-CeO2/NaX for temperature swing oxidation of benzene, toluene and xylene

2014 ◽  
Vol 12 (4) ◽  
pp. 492-501 ◽  
Author(s):  
Aurimas Urbutis ◽  
Saulius Kitrys
Keyword(s):  
Operating Conditions ◽  
Cyclic Process ◽  
Dual Function ◽  
Preparation Technique ◽  
Flow Rates ◽  
Bed Temperature ◽  
Temperature Swing ◽  
Oxidation Performance ◽  
Benzene Toluene ◽  
Two Stages

AbstractA less common cyclic process of decontamination of benzene, toluene and o-xylene (BTX) using a dual function adsorbent-catalyst, referred to as the temperature swing oxidation, is introduced and discussed in this research. Preparation technique and characterization of the dual function adsorbent-catalyst CuO-CeO2/NaX are presented. The temperature swing oxidation of BTX consists of two stages: adsorption of the VOC from the stream saturating the adsorbent-catalyst at different levels and catalytic oxidation of concentrated VOC induced by raising bed temperature at different flow rates of regenerative air. The results indicate that at lower saturation levels and lower flow rates of regenerative air a complete oxidation performance is better. The highest obtained values of the overall conversion of toluene, o-xylene and benzene into CO2 and H2O were 99.3, 99.8 and 77.5%, respectively, proving that the temperature swing oxidation using a dual function adsorbent-catalyst is a promising VOC decontamination technique under properly selected operating conditions.

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