Decontamination performance of air filter paper impregnated with zirconium hydroxide on sulfur mustard

Using zirconium hydroxide as a decontaminant, a kind of self-decontaminating air filter paper that can effectively degrade HD was successfully prepared by impregnating. The morphology and filtration efficiency of the filter paper before and after immersing were compared. The filtration efficiency increased linearly and slowly, with the regression equation: η=0.0001L+99.971. The liquid-solid decontamination reaction of HD on zirconium hydroxide powder and self-decontaminating filter paper conformed to the kinetic of quasi-first-order reaction and found that half-lives were 0.4 h and 2.1 h respectively. Good degradation performance for HD was exhibited and the degradation rate reached more than 99 % in 12 hours. Reaction products were analysed by GC-MS, which displayed that HD was decomposed through the substitution of chlorine and the elimination of H on α-C. The ultimate decontamination products were thiodiglycol and 2-hydroxyethyl vinyl sulfide without erosive toxicity.

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Vulcanization of an Ethylene Propylene Diene Rubber

Rubber Chemistry and Technology ◽

10.5254/1.3547171 ◽

1968 ◽

Vol 41 (2) ◽

pp. 316-329 ◽

Cited By ~ 3

Author(s):

H. K. Frensdorff

Keyword(s):

Rate Constants ◽

Order Reaction ◽

Double Bonds ◽

Fast Reaction ◽

First Order ◽

Equilibrium Swelling ◽

Before And After ◽

Ethylene Propylene Diene Rubber ◽

Two Stages ◽

Diene Rubber

Abstract This study concerns the sulfur vulcanization of EPT with dithiocarbamate accelerators. The reactions undergone by the accelerators are equivalent to those found during natural rubber or SBR vulcanization; TMTM and TMTD are almost completely converted to ZDMC. During vulcanization about 50% of the double bonds are saturated, and approximately one crosslink is formed for each two double bonds initially present. Equilibrium swelling measurements before and after mercaptan cleavage were used to determine the concentration of all crosslinks and that of monosulfide ones as functions of vulcanization conditions. Vulcanization kinetic were followed by Monsanto rheometer measurements. The process takes place in two stages: an initial fast reaction representing vulcanization by the primary accelerator, followed by a slower first order reaction due to acceleration by ZDMC. Accelerator, sulfur, and zinc oxide concentrations have little effect on the rate constants which, however, are nearly proportional to polymer unsaturation. The rate constants approximately double with each temperature rise of 10° C.

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Pretreatment of pesticide wastewater by photocatalytic oxidation

Water Science & Technology ◽

10.2166/wst.1997.0497 ◽

1997 ◽

Vol 36 (2-3) ◽

pp. 117-122 ◽

Cited By ~ 2

Author(s):

Ming-Chun Lu ◽

Jong-Nan Chen

Keyword(s):

Organic Carbon ◽

Photocatalytic Oxidation ◽

Parent Compound ◽

Order Reaction ◽

Toxic Chemicals ◽

Reaction Products ◽

Model Compounds ◽

First Order ◽

Different Characteristics ◽

Complete Mineralization

The toxic chemicals, 2,4-D (a herbicide) and propoxur (an insecticide), were used as the model compounds in these experiments. Total organic carbon analyzer was used to assess the efficiency of photocatalytic mineralization. Microtox bioassay was employed in evaluating the toxicity of solutions treated by photocatalysis. Ultraviolet absorption spectra were also used for showing the different characteristics of the compounds undergoing photocatalytic oxidation. Results show that propoxur is less degradable than 2,4-D, and the photomineralization of these pesticides follows a behavior of first-order reaction. Products of 2,4-D and propoxur are more toxic than the parent compound after partial photodegradation. This shows that complete mineralization is necessary for total detoxification of these pesticides. In other words, toxicity is an important criteria in assessing the pretreatment process.

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Degradation of chlorinated benzaldehydes in aqueous solutions by UV-irradiation

International Journal of Photoenergy ◽

10.1155/s1110662x02000156 ◽

2002 ◽

Vol 4 (4) ◽

pp. 133-139 ◽

Cited By ~ 1

Author(s):

Miray Bekbölet ◽

Nikola Getoff

Keyword(s):

Aqueous Solutions ◽

Hplc Analysis ◽

Degradation Rate ◽

Uv Light ◽

Order Reaction ◽

Quantum Yields ◽

Homolytic Cleavage ◽

First Order ◽

Probable Reaction Mechanism ◽

Probable Reaction

Photoinduced degradation of chlorinated benzaldehydes was investigated using UV light with λ = 253.7 nm in aerated aqueous solutions. Substrate degradation rate as expressed by first order reaction kinetics revealed rate constants, k;7.45×10−3min-1,3.90×10−3min-1and3.90×11−2min-1for 2- chlorobenzaldehyde, 3-chlorobenzaldehyde and 4-chlorobenzaldehyde respectively. The decomposition of the substrates was related to the formation of chloride and formaldehyde by homolytic cleavage processes. initial quantum yields and photochemical “GiPH-values” are reported for the degradation of the substrates. Based on the qualitative HPLC analysis, a probable reaction mechanism for the photoinduced degradation of chlorinated benzaldehydes is also presented.

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Degradasi Larutan Pewarna Azo Tekstil Menggunakan Sistem Heterogenan O3, O3/UL, O3/TiO2/UL dan O3/H2O2/UL

Jurnal Teknologi ◽

10.11113/jt.v35.602 ◽

2012 ◽

Author(s):

Razak Ali ◽

Wan Azelee Wan Abu Bakar ◽

Azmi Aris ◽

Pak Yan Mok

Keyword(s):

Hydrogen Peroxide ◽

Azo Dye ◽

Degradation Rate ◽

Degradation Process ◽

Order Reaction ◽

Pseudo First Order Reaction ◽

First Order ◽

Photocatalytic System ◽

Degradation Degree ◽

Oxidation System

Rawatan larutan pewarna azo tekstil, Sumifix Supra Blue BRF 150% Gran (SSBBRF) melibatkan sistem yang berbeza, O3, O3/UL, 03/TiO2/UL dan O3/H2O2/UL telah dikaji. Keputusan yang diperoleh menunjukkan bahawa degradasi larutan SSBBRF melalui sistem pengoksidaan berasaskan ozon adalah lebih efektif berbanding dengan sistem pemangkinanfoto. Darjah degradasi keserapan dan warna yang tinggi serta degradasi COD dan TOC yang ketara, menunjukkan bahawa sistem pengoksidaan yang berasaskan ozon berupaya memecahkan pewarna azo dalam air tercemar kepada spesies yang lebih terbiorawat. Keputusan yang diperoleh juga menunjukkan bahawa sistem pengozonan (O3 sahaja dalam keadaan gelap), dan sistem gandingan pengozonanfoto–pemangkinanfoto (03/TiO2/UL) tidak menunjukkan perbezaan kadar degradasi pewarna azo yang ketara berbanding sistem pengozonanfoto (O3/UL) tetapi penambahan hidrogen peroksida (H2O2) ke dalam sistem 03/UL mampu meningkatkan lagi kadar degradasi pewarna azo. Perbandingan keupayaan sistem yang dikaji bagi degradasi pewarna SSBBRF adalah mengikut urutan: 03/H202/UL > O3/UL > O3/TiO2/UL > O3 > TiO2/UL. Proses pendegradasian pewarna SSBBRF mematuhi kinetik tindak balas tertib pertama pseudo dengan nilai pemalar kadar, k, dari julat 0.20 min–1 hingga 0.24 min–1 untuk 20 minit yang pertama. Kata kunci: Pewarna azo; pengozonanfoto; pemangkinanfoto; hidrogen peroksida Treatment of aqueous textile azo dye, Sumifix Supra Blue BRF 150% Gran (SSBBRF) by different kinds of systems, 03, O3/UV, 03/TiO2/UV and O3/H2O2/UV has been investigated. The results obtained showed that the degradation of SSBBRF solution involving ozone–assisted oxidation system is more superior compared to photocatalytic system. The high degradation degree of Absorbance and colour as well as the significant degradation of COD and TOC indicated that the ozone–assisited system is capable of disrupting the azo dye in the wastewater to more biotreatable species. The results obtained, also showed that ozonation (O3 alone in dark) system and simultaneous photoozonation–photocatalytic (03/TiO2/UV) system do not give significant effect to the degradation rate of azo dye in comparison with photoozonation (O3/UV) system, but addition of hydrogen peroxide (H202) in the O3/UV system may enhance the degradation rate of the azo dye. The degradation potential of these different systems studied towards SSBBRF are in the following the order: O3/H2O2/UV > O3/UV > 03/TiO2/UV > O3 > TiO2/UV. The degradation process of SSBBRF is following the kinetic of pseudo–first order reaction with the rate constants, k, ranging from 0.20 min–1 up to 0.24 min–1 for the first 20 minutes of the reactions. Key words: Azo dye; photoozonation; photocatalysis; hydrogen peroxide

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Vulcanization of Elastomers. 30. Kinetics of the Decrease of Sulfur Concentration during Vulcanization

Rubber Chemistry and Technology ◽

10.5254/1.3540232 ◽

1961 ◽

Vol 34 (2) ◽

pp. 606-628 ◽

Cited By ~ 4

Author(s):

Walter Scheele ◽

Martin Cherubim

Keyword(s):

Initial Rate ◽

Order Reaction ◽

Usual Sense ◽

Complex Nature ◽

Reaction Products ◽

Sulfur Concentration ◽

First Order ◽

Synthetic Rubber ◽

Kinetics Of ◽

Characteristic Trend

Abstract The present discussion deals with the explanation and critical analysis of the kinetics of the decrease in concentration of sulfur in accelerated and unaccelerated vulcanizations of natural and synthetic rubber. A marked distinction is made between the time law and the dependence on concentration of the rate of decrease of sulfur, since there is lack of agreement between them, both in accelerated and unaccelerated vulcanizations, which indicates the complex nature of vulcanization. In unaccelerated vulcanization, the sulfur concentration drops, at all temperatures and independent of the concentration, according to a time law with exponent n=0.6. On the other hand, the dependence on concentration of the initial rate of sulfur decrease proceeds according to a first order reaction. These relations make it seem probable that sulfur decrease involves a process which is catalyzed by reaction products. In accelerated vulcanization, the reduction of concentration of sulfur also is expressed by a time law with the exponent n<1, and this too is independent of temperature and concentration of reactants (sulfur and accelerator). However, the concentration dependence of the rate of sulfur decrease cannot be expressed by a power law, so that we find no order of reaction in the usual sense. We attempt to explain the characteristic trend of the initial rate of sulfur decrease with sulfur concentration at constant accelerator content, or with accelerator concentration at constant sulfur content, by assuming that the vulcanization takes place through intermediate compounds. The pertinent theoretical conceptions are disclosed and critically examined and the attempt is made to show the extent to which they may be brought into accord with the experimental data.

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Removal of tetrachloroethylene in an anaerobic fixed-bed reactor immobilized with Clostridium bifermentans DPH-1

Water Science & Technology Water Supply ◽

10.2166/ws.2001.0027 ◽

2001 ◽

Vol 1 (2) ◽

pp. 107-114

Author(s):

Y.C. Chang ◽

K. Asanuma ◽

M. Hatsu ◽

K. Takamizawa

Keyword(s):

Continuous Culture ◽

Degradation Rate ◽

Cell Mass ◽

Fixed Bed ◽

Order Reaction ◽

Fixed Bed Reactor ◽

Strictly Anaerobic ◽

First Order ◽

Clostridium Bifermentans ◽

Specific Degradation

An upflow fixed-bed reactor was evaluated for the removal of tetrachloroethylene (PCE) by a strictly anaerobic, PCE dechlorinating bacterium, Clostridium bifermentans DPH-1 immobilized on sterile ceramic beads. The ceramic beads provide a large surface area for development of cell mass in the column. For kinetic experiments, the conventional first-order reaction kinetics was applied to evaluate the batch and continuous immobilized reactors. Velocity constants (KB and KC) under the batch culture and continuous culture were determined to be 1.9 × 10–2 (mg protein–1h–1) and 1.4 × 10–2 (mg protein–1h–1), respectively. Maximum specific degradation rate of PCE was calculated as 0.16 (10–3 μmol mg protein–1h–1 from average influent concentration of PCE (12 μM) in the bioreactor. Simultaneously maximum volumetric degradation rate was also computed as 10.2 μmol l–1h–1. The volumetric degradation rate was relatively higher than those of other reactors. In order to maintain the efficiency of PCE dechlorination, 20 h or more HRT in the reactor system was required.

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Dual-purpose high-efficiency air filter paper loaded with reactive zirconium hydroxide for the filtration aerosols and degradation of chemical warfare agents

RSC Advances ◽

10.1039/d1ra06903a ◽

2021 ◽

Vol 11 (56) ◽

pp. 35245-35257

Author(s):

Xingqi Huang ◽

Ting Zhao ◽

Hongpeng Zhang ◽

Chunxiao Yan ◽

Jiulong Sha ◽

...

Keyword(s):

Filter Paper ◽

High Efficiency ◽

Chemical Warfare Agents ◽

Zirconium Hydroxide ◽

Chemical Warfare ◽

Addition Method ◽

Dual Purpose ◽

Air Filter ◽

Dual Functional ◽

Warfare Agents

Dual-functional air filter paper with addition of Zr(OH)4 was prepared by an intra-pulp addition method, whose filtration performance is maintained while the decontamination performance is added for HD and VX.

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Filtration efficiency improvement of air filter paper for fine particles by electrospinning technology

BioResources ◽

10.15376/biores.16.3.5220-5233 ◽

2021 ◽

Vol 16 (3) ◽

pp. 5220-5233

Author(s):

Weiyin Su ◽

Lanfeng Hui ◽

Xiaoyan Ma ◽

Qian Yang ◽

Wanhong Sun

Keyword(s):

Pore Size ◽

Filter Paper ◽

Fine Particles ◽

Filtration Efficiency ◽

Research Progress ◽

High Porosity ◽

Air Filter ◽

Filtration Performance ◽

Initial Resistance ◽

Good Filtration

Due to great advantages, such as simple operation, high porosity, and good fiber continuity, the working principle and research progress of electrospinning technology was studied and polyvinyl alcohol (PVOH) nanofibers were prepared via this process. Air filter paper was used as the receiving substrate to prepare electrospun nano air filter paper (NAFP). The PVOH concentration, static voltage, and receiving distance, were tested to explore the influence of spinning parameters on the filtration performance. Further, the microfiber morphology of the electrospun NAFP was observed. The performance of filter paper, including air permeability, pore size, initial resistance, filtration efficiency, and dust retention, were tested. The results showed that the electrospun NAFP had better filtration performance compared to the air filter paper, and simultaneously they had lower initial resistance and higher precision filtration efficiency. The nanofiber influenced the surface of the air filter paper, as it sharply reduced the pore size. When the spinning condition was 10%, 21 kV, and 15 cm, the pore size decreased approximately 0.6 times of the original, which meant the electrospun NAFP could capture particles ≥ 0.2 μm in size. Finally, after three repeated uses, the good filtration performance was maintained.

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Photo-catalytic degradation of gaseous pollutants in paper mills of southern China

TAPPI Journal ◽

10.32964/tj17.03.167 ◽

2018 ◽

Vol 17 (03) ◽

pp. 167-178 ◽

Cited By ~ 2

Author(s):

Xin Tong ◽

Jiao Li ◽

Jun Ma ◽

Xiaoquan Chen ◽

Wenhao Shen

Keyword(s):

Degradation Rate ◽

Southern China ◽

Catalytic Degradation ◽

Pulp And Paper ◽

Gaseous Pollutants ◽

Pulp And Paper Mills ◽

Paper Mills ◽

Initial Concentration ◽

First Order ◽

First Order Kinetics

Studies were undertaken to evaluate gaseous pollutants in workplace air within pulp and paper mills and to consider the effectiveness of photo-catalytic treatment of this air. Ambient air at 30 sampling sites in five pulp and paper mills of southern China were sampled and analyzed. The results revealed that formaldehyde and various benzene-based molecules were the main gaseous pollutants at these five mills. A photo-catalytic reactor system with titanium dioxide (TiO2) was developed and evaluated for degradation of formaldehyde, benzene and their mixtures. The experimental results demonstrated that both formaldehyde and benzene in their pure forms could be completely photo-catalytic degraded, though the degradation of benzene was much more difficult than that for formaldehyde. Study of the photo-catalytic degradation kinetics revealed that the degradation rate of formaldehyde increased with initial concentration fitting a first-order kinetics reaction. In contrast, the degradation rate of benzene had no relationship with initial concentration and degradation did not conform to first-order kinetics. The photo-catalytic degradation of formaldehyde-benzene mixtures indicated that formaldehyde behaved differently than when treated in its pure form. The degradation time was two times longer and the kinetics did not reflect a first-order reaction. The degradation of benzene was similar in both pure form and when mixed with formaldehyde.

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Leaching Kinetics of Atrazine and Inorganic Chemicals in Tilled and Orchard Soils

International Agrophysics ◽

10.2478/intag-2014-0012 ◽

2014 ◽

Vol 28 (2) ◽

pp. 231-237 ◽

Cited By ~ 2

Author(s):

Lech W. Szajdak ◽

Jerzy Lipiec ◽

Anna Siczek ◽

Artur Nosalewicz ◽

Urszula Majewska

Keyword(s):

Reaction Rate ◽

Inorganic Compounds ◽

Model Performance ◽

Order Reaction ◽

First Order Reaction ◽

Order Kinetic ◽

Time Data ◽

First Order ◽

Concentration Changes ◽

Reaction Constants

Abstract The aim of this study was to verify first-order kinetic reaction rate model performance in predicting of leaching of atrazine and inorganic compounds (K+1, Fe+3, Mg+2, Mn+2, NH4 +, NO3 - and PO4 -3) from tilled and orchard silty loam soils. This model provided an excellent fit to the experimental concentration changes of the compounds vs. time data during leaching. Calculated values of the first-order reaction rate constants for the changes of all chemicals were from 3.8 to 19.0 times higher in orchard than in tilled soil. Higher first-order reaction constants for orchard than tilled soil correspond with both higher total porosity and contribution of biological pores in the former. The first order reaction constants for the leaching of chemical compounds enables prediction of the actual compound concentration and the interactions between compound and soil as affected by management system. The study demonstrates the effectiveness of simultaneous chemical and physical analyses as a tool for the understanding of leaching in variously managed soils.

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