The degradation of two polluted textile wastewaters from SOITEX (silk and textile) industry using the plasma-catalytic process, has been studied by non-thermal Gliding arc technique coupled to ...Degussa P25 titanium dioxide (TiO(2)) as photo-catalyst. Experiments were carried out to optimise the amount of phtoto-catalyst. The results showed that maximum degradation was attained for 3 g L(-1) TiO(2) concentration. For wastewater (1) degradation was 95% at the end of 60 min of treatment time. The same wastewater was completely decolourised after only 30min of plasma-catalytic treatment time. In parallel, the biodegradability was significantly enhanced through 20 min of exposure to the plasmagenous source for both wastewater samples. Turbidity of wastewater (1) and wastewater (2) decreased with rate constants of 0.015 and 0.017m in(-1), respectively. The TiO(2)-mediated Gliding Arc discharge (GAD(TiO(2)) showed potential application for the treatment of liquid wastes, resulting in the mineralization of the wastewater samples confirmed by chloride, sulphate and phosphate ions formation. In both cases of GAD treatments, with and without photo-catalyst, the plasmagenous process proves efficient in the field of wastewaters degradation.
The aim of this work is to propose a plan for the choice of a suitable process for the treatment of a young leachate from municipal solid waste. Classical processes were applied: Fenton process, the ...coupling coagulation-Fenton process and the adsorption on powdered activated carbon (PAC). The study involves synthesised leachates from three types of wastes collected from sanitary landfill (SL): leachate of putrescible fraction (Lp), paper-cardboard (Lpc), sawdust (Ls) and the one of landfill (Lsl). The optimal operating conditions have been determined for the three processes: Fenton: H2O2 = 6.8 g L-1 and Fe2+ = 2.8 g L-1, coagulation: Fe3+ = 0.3 g L-1 and adsorption: PAC = 60 g L-1. The three processes gave reduction rates of chemical oxygen demand ranging from 50% to 85% for Lp, 87% to 97% for Lpc and 61% to 87% for Ls. Whereas for Lsl, it was of 45%, 56% and 80% for the Fenton, coagulation-Fenton and adsorption processes, respectively. A modelling study was conducted to calculate the chemical oxygen demand of leachate produced during 25 years for different thicknesses of waste. This predicted value is used to advise for the process treatment to apply and to assess the environmental impacts in the long term.
Anthraquinonic acid green 25 (AG 25) removal was investigated by plasmachemistry using non-thermal gliding arc at atmospheric pressure in the presence of SnAPO4-5 and SnAPO4-11 synthesised catalysts.
...•Combined system of non thermal plasma and tin containing microporous aluminophosphates was utilised for AG 25 removal.•The isomorphous substitution of tin in aluminophosphate framework was studied by different characterisation methods.•The catalytic properties of SnAPOs were studied for the plasmacatalytic treatment of AG 25.•Kinetic of the AG 25 removal over SnAPOs catalysts was investigated on the basis of the Langmuir–Hinshelwood (L–H) model.
In this paper, the plasmacatalytic removal of an anthraquinonic dye type acid green 25 (AG 25) in aqueous solutions has been investigated in the presence of microporous tin containing aluminophosphates as catalysts under a gliding arc discharge plasma.
The catalysts have been synthesised in AEL and AFI structure types by static hydrothermal crystallisation. These materials were characterised by elemental analysis, X-ray diffraction, scanning electron microscopy, N2 adsorption measurements (BET) and Mössbauer spectroscopy. These analyses showed significant catalytic properties of these materials.
The degradation process has been monitored during the experimental runs through UV/visible spectroscopy and chemical oxygen demand (COD). The results showed a good synergetic effect between the tin-containing aluminophosphate particles and the highly reactive plasma species. Moreover, it was found that these catalysts can be reused several times.
Kinetics of the dye removal has also been investigated on the basis of the Langmuir–Hinshelwood (L–H) model.
The gliding arc discharge is a cheap and efficient nonthermal plasma technique able to degrade organic compounds dispersed in water at atmospheric pressure. Alizarin Red Sulfonate (ARS) is selected ...as a stable quinonic dye. Exposure of the dye solution to the discharge in a batch reactor induces two successive reaction steps according to the treatment conditions. Direct exposure of the solution to the discharge induces simultaneous bleaching and COD evolution. In postdischarge conditions, that is, after the discharge is switched off, the reactions keep on developing. This study thus underlines two key features: the ability of glidarc discharges to degrade recalcitrant molecules and the low cost of the process which requires short exposure times. A model mechanism involves peroxynitrite as a likely active species formed in the discharge and involved in postdischarge phenomena in aqueous solutions and suggests short exposure times and much longer postdischarge times for optimized pollutant abatement.
•Exploring Cu2Zn1−xCdxSnS4 nanostructures.•Synthesis the optical properties of Cu2Zn1−xCdxSnS4 nanostructures.•Characterize the Cu2Zn1−xCdxSnS4 nanostructures.•Verify refractive index and optical ...dielectric constant.•Elaborate the electrical characteristics of Cu2Zn1−xCdxSnS4 nanostructures.
While efforts have been made to synthesize quaternary alloy nanostructures with high surface area for application in many fields, a detailed exploration of quinternary alloy nanostructures has not been reported until now. This work investigates the optimum crystallization parameters for reducing crystal defects in Cu2Zn1−xCdxSnS4 quinternary alloy nanostructures. Alloy nanostructures with different Zn and Cd contents were grown by a sol–gel method. The analytical results confirmed a multi-phase polycrystallinity of the samples, and the variations in their energetic transitions and optical properties with Cd content were investigated. The morphology and topography of the samples were also observed. Our results are supported by several related studies in the literature.
The requirement for environmentally friendly catalysts for the isomerization of alkanes has prompted research on the tungstate-zirconia (WZ) system. The present work examines the activity and ...selectivity of lanthanum (La) promoted tungstate-zirconia (LWZ) and niobium (Nb) promoted tungstate-zirconia (NWZ) catalysts. In this study, 1 % La promoted WZ (1 % LWZ) and 1 % Nb promoted WZ (1 % NWZ) catalysts were investigated in isomerization of n-butane in the presence of hydrogen. The studied catalysts were characterized by different methods: nitrogen physisorption, temperature programmed desorption of NH3, thermogravimetric analysis, and X-ray diffraction. The catalytic activity and selectivity were significantly improved by the addition of 1 % Nb. The redox process in the Nb-containing catalyst (1 % NWZ) played a central role by providing the highest acidic sites (283.53 µmol g–1) with appropriate activation energies for the skeletal rearrangement of the reactant (n-butane). Furthermore, this study highlights the determining role of the transfer process of adsorbed species from ZrO2 to W as well as to the Nb environment. The conversion of n-butane (27.34 %) and the selectivity to i-butane (92.34 %) for NWZ were significantly higher than WZ and LWZ catalysts. The experimental results revealed that Nb was a more effective promoter than La.
The degradation of aqueous solutions of various dyes (e.g., Orange I, Crystal Violet, and Eriochrome Black T) used for the textile industry was performed by means of a special nonthermal quenched ...plasma technique (i.e., the gliding arc technique, which results from an electric discharge at atmospheric pressure and ambient temperature). The gaseous species formed in the discharge, and especially the OH radicals, induce strong oxidizing effects in the target solution, so that bleaching of the solution and degradation of the solute result, as evidenced by absorbance and chemical oxygen demand (COD) measurements. The two processes were considered as matching reactions, and overall kinetic data were derived when possible. A tentative mechanism based on literature data is also presented.
•We developed an original prototype of gliding arc discharge.•The new prototype permit to treat laminar falling liquid films (GAD-FF).•The optimized working parameters are: plate inclination angle ...α=45° – circulation rate ω=1Lh−1 – channel width Δ=3mm.•AG25 dye discolouration and degradation reach 95% and 90% respectively after 12 cycles exposition.•The process can be extrapolated to pilot and/or industrial scale.
Gliding arc discharge (GAD) reactors are continuously in progress in order to improve the treatment efficiency of recalcitrant compounds. However, up to now, they remain difficult to transfer to industrial applications because of some technical constraints in their design. In this study, a new efficient prototype is proposed for the treatment of gravity falling film shaped of liquid effluents. The liquid flow rate is now continuous as the tank containing the solution to be treated is replaced by an inclined plate along which flows the liquid. The various working parameters are optimized and the new prototype efficiency is tested on discolouration and degradation of the anthraquinonique Acid Green 25. The optimized values obtained are: the liquid flow rate ω=1Lh−1, the plate tilt angle α=45° and the channel width Δ=3mm. The rates of discolouration and degradation reach 95% and 90% respectively after 12 cycles (180min) of plasma exposition. The GAD in the presence of humid air generates highly oxidizing radical species such as •OH with a standard potential E°(•OH/H2O)=2.85V/SHE and its reducer agent H2O2 E°(H2O2/H2O)=1.68V/SHE.
While efforts have been made to synthesize quaternary alloy nanostructures with high surface area for application in many fields, a detailed exploration of quinternary alloy nanostructures has not ...been reported until now. This work investigates the optimum crystallization parameters for reducing crystal defects in ... quinternary alloy nanostructures. Alloy nanostructures with different Zn and Cd contents were grown by a sol-gel method. The analytical results confirmed a multi-phase polycrystallinity of the samples, and the variations in their energetic transitions and optical properties with Cd content were investigated. The morphology and topography of the samples were also observed. Our results are supported by several related studies in the literature. (ProQuest: ... denotes formulae/symbols omitted.)
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