Initial Toluene Concentration Research Articles

Tailoring oxygen vacancies by synergy of dual metal cations in LaCo0.8M0.2O3 (M = Cu, Ni, Fe, Mn) towards catalytic oxidation of toluene

Enhancing the catalytic performance of transition metal oxide catalysts is prerequisite for the efficient catalytic oxidation of VOCs. Here the B-site partially substituted LaCoO3 (LaCo0.8M0.2O3, M = Cu, Ni, Fe and Mn) catalysts was synthesized for the catalytic oxidation of toluene. Among these catalysts, LaCo0.8Ni0.2O3 catalyst exhibits remarkable catalytic performance for toluene with T50 = 226 °C and T90 = 239 °C at an initial toluene concentration of 1000 ppm, whose T50 (and T90) reduced by 13 °C (and 34 °C) compared with that of LaCoO3. Confirmed by BET, XPS, and EPR characterizations, Ni substitution improves the specific surface area, Co3+/Co2+ ratio, Oads/Olatt ratio, and oxygen vacancies concentration. This improvement indicates the improvement of adsorption and activation of reactant, mobility of oxygen species, thereby contributing to the superior catalytic performance in toluene oxidation. The B-site of LaCoO3 occupied by dual cations caused the lattice distortion and formation of oxygen vacancies due to the ionic radii difference between Co and Ni cations. Moreover, the apparent activation energy of LaCo0.8Ni0.2O3, as the determining factor for the catalytic oxidation rate, was remarkably reduced. Our findings confirmed the synergy effect of Co and Ni cations at B-site on the enhancement of catalytic activity, which provides a promising strategy for oxygen vacancy engineering.

Kaolin-Derived Porous Silico-Aluminate Nanoparticles as Absorbents for Emergency Disposal of Toluene Leakage.

To rapidly eliminate toluene from aqueous environments during leakage accidents, this paper synthesized porous silico-aluminate nanoparticles (SANs) via a hydrothermal method, using cost-effective and non-toxic natural kaolin as the basic raw material. The morphology and structure of the porous SANs were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and BET-specific surface area tests. The effects of different conditions, such as the dosage of porous SANs, initial concentration of toluene, temperature, capture time, and pH, on the adsorption performance of porous SANs were analyzed. The as-prepared SANs exhibited a high removal efficiency and rapid adsorption performance toward toluene in aqueous solution. Finally, the kinetics of the adsorption of toluene in aqueous solution by porous SANs were investigated. The mechanism of the adsorption of toluene by porous SANs was further discussed. These findings provide a cost-effective and highly efficient absorbent for the emergency disposal of toluene leakage accidents.

Promotion of toluene catalytic oxidation by M−La/CoOx catalysts directly prepared from Co-MOFs precursors

Volatile organic compounds (VOCs) are identified as volatility and toxicity, and have become major pollutants in the atmosphere. The development of low-energy and high-efficiency environmentally friendly VOCs purification technologies is urgent. Therefore, in this paper, a series of M−La/CoOx (M = La addition) catalysts with different La additions were synthesized by a combination of impregnation and calcination using Co-MOFs as precursors. It was shown that the catalytic activity of the constructed 0.012-La/CoOx catalyst was unexpectedly improved (T90% = 227 °C) under optimal reaction conditions (catalyst mass-air velocity = 60000 mL/(g•h)), initial toluene concentration = 1000 ppm) when employing gaseous toluene (C7H8) as typical target VOCs. Among the La-doping catalysts, the catalysts containing La on the surface have smaller grain sizes as well as more homogeneous grain distributions than the pure Co3O4-MOF catalysts. 0.012-La/CoOx displayed the highest activity, which is attributed to its smaller particle size, larger specific surface area (SSA), richer content of Co3+ and surface Oads, which could enhance the oxygen mobility and the redox performance. The possible degradation mechanism of toluene on 0.012-La/CoOx was revealed using in-situ DRIFTS. This work might provide guidance for the development of efficient and environmentally friendly catalytic oxidation of toluene.

Enhanced toluene removal from aqueous solutions using reed straw-derived biochar

Abstract The escalating threat of pollutants, particularly aromatic hydrocarbons like benzene, toluene, ethylbenzene and xylene (BTEX), in aquatic environments necessitates effective remediation strategies. This study explores the potential of biochar derived from common reed (Phragmites australis) as a sustainable and multifaceted tool for the removal of toluene, a representative BTEX compound, from aqueous solutions. By harnessing reed straw as the precursor material for biochar production, this research showcases an environmentally friendly alternative to conventional disposal methods, such as incineration, offering the dual benefit of pollutant removal and carbon emissions reduction. The influence of pyrolysis temperature on biochar properties and its adsorption efficiency for toluene were rigorously examined, revealing a direct correlation between temperature and biochar’s pollutant sequestration capabilities. Results indicate that higher pyrolysis temperatures led to biochar (RB-750) with superior specific surface area (68.07 m2/g) and enhanced adsorption capabilities, demonstrating its potential as a powerful adsorbent in water treatment. The scanning electron microscope analysis revealed a complex, porous structure rich in active sites, validating the biochar’s suitability for pollutant adsorption. Optimal dosage was determined at 8 g/l, achieving an impressive toluene removal efficiency of 98.1%. Additionally, pH and initial toluene concentration significantly influenced removal efficiency. This study underscores the multifaceted potential of reed straw-derived biochar in combating water pollution while concurrently contributing to carbon emissions reduction through sustainable utilization of abundant wetland resources. Further research should delve into the impact of real-world conditions on its effectiveness, promising innovative solutions for environmental remediation efforts with a reduced carbon footprint.

Removal of toluene via non-thermal plasma generated by applying rare-earth tungsten electrode and nanosecond pulsed power supply.

The objective of this investigation is to evaluate the characteristics associated with degradation of toluene through the utilization of non-thermal plasma (NTP) generated via application of a low-work-function electrode and nanosecond pulsed power supply. Initially, a comparative analysis is made between toluene removal efficiency utilizing the low-work-function electrode and that achieved with the conventional stainless-steel electrode. The outcomes demonstrate that NTP generated by the low-work-function electrode exhibits markedly superior removal efficiency for toluene in comparison to the stainless-steel electrode operating at the same voltage. Subsequently, the impacts of voltage, pulse frequency, and initial concentration of toluene on the removal efficiency and production of by-products are investigated. It is found that as the voltage and frequency increase, the removal efficiency also increases, and a maximum toluene removal efficiency of 87.2% is achieved at a voltage of 12,000V and pulse frequency of 2000Hz. The removal efficiency first increases and then decreases with increasing toluene initial concentration. The investigation also finds that energy yield is negatively correlated with voltage and pulse frequency and positively correlated with the initial concentration. Finally, the reaction products were subjected to quantitative analysis using GC-MS. Based on the analysis results, potential reaction pathways are inferred.

The resin-supported iron-copper bimetallic composite as highly active heterogeneous Fenton-like catalysts for degradation of gaseous toluene.

In this study, a resin-supported iron-copper bimetallic heterogeneous Fenton catalyst with excellent removal performance, superior economy and outstanding recoverability was synthesized by an impregnation method and used to remove gaseous toluene. Experiments disclosed that 3-FeCu@LXQ-10 possessed extremely high catalytic capacity. At a temperature of 30 °C, an initial toluene concentration of 200 mg/m3 and H2O2 atomization amount of 3 mmol/h, the toluene removal efficiency of 3-FeCu@LXQ-10 was 97.50%. Experimental tests had revealed that the bimetallic supported catalysts exhibited higher catalytic activity than single metal-supported catalysts, owing to an interaction effect between iron and copper metal ions. Furthermore, electron paramagnetic resonance (EPR) and radical quenching tests were carried out, and the results indicated •OH radicals performed a key role in the Fenton-like process. In addition, the iron-copper bimetallic catalysts exhibited good reusability and stability characteristics during six degradation cycles. This study shows promising potential in using FeCu@LXQ-10 as a heterogeneous catalyst for removing toluene.

Adsorption Characteristics and Influencing Factors of Chlorinated and Aromatic Hydrocarbons on Aquifer Medium

To determine the competitive adsorption characteristics and influencing factors of chlorinated and aromatic hydrocarbons on the aquifer medium, toluene, benzene, 1,2−dichloropropane, and 1,2,3−trichloropropane (TCP) were selected as typical pollutants for adsorption tests. The results showed that the adsorption process of pollutants on the aquifer medium conformed to the first−order kinetic and Henry linear model equation, and the adsorption capacity decreased in the order of toluene, benzene, 1,2−dichloropropane, and TCP. Benzene promoted the adsorption of toluene on the aquifer medium, while toluene reduced the adsorption of benzene conversely. 1,2−dichloropropane restrained the adsorption of TCP, and TCP had no significant effect on the adsorption of 1,2−dichloropropane. The adsorption capacity of TCP on the aquifer increased with the concentration of toluene. TCP acted as a stimulus for the adsorption of toluene when the initial concentration of toluene was lower than 2 mg/L. In contrast, TCP served as an inhibitor for the adsorption of toluene on the aquifer medium. Furthermore, the adsorption of all pollutants increased with decreasing medium size. The promotion rates for aromatic and chlorinated hydrocarbons were 7.2~41.1% and 2.7~27.1%, suggesting that the promotion effect on aromatic hydrocarbons was stronger than that on chlorinated hydrocarbons. Natural organic matter (NOM) inhibited the adsorption of pollutants on the aquifer medium (especially for high concentrations of chlorinated hydrocarbons), and the adsorption rate increased by more than 60% when OM decreased from 0.25% to 0.08%. Clay minerals improved the adsorption of organic pollutants in different compound pollution systems, and montmorillonite exhibited a stronger promoting effect than kaolin.

Gaseous toluene heterogeneous oxidative degradation by iron-based hypercrosslinked polymeric resin LXQ-10

Heterogeneous Fenton-like reaction for gaseous toluene removal was enhanced by loading an amount of iron elements onto the hypercrosslinked polymeric resin (LXQ-10) as a novel catalyst. Characterization and experiment results confirmed that Fe/LXQ-10 with great catalytic and stability performance were successfully synthesized. The effects of several key running parameters such as iron loading amount, initial toluene concentration, H2O2 concentration, and reaction temperature were investigated. Under the optimal conditions for a Fenton-like reaction (gaseous toluene concentration, 200 mg/m3; H2O2 concentration, 0.15 mol/L; reaction temperature, 303 K), 3-Fe/LXQ-10 was identified to produce OH radical and the toluene removal efficiency reached 93.56%. Gas chromatography-mass spectrometry (GC–MS) was employed to detect the byproducts in the toluene removal process, and the possible degradation pathway of toluene was explored. Radical quenching tests and EPR investigation were carried out to clarify the contribution of OH radical in the Fenton-like process. Physical adsorption and OH oxidation were the possible mechanisms of toluene removal. In addition, the catalyst maintained its activity after the six cycles. suggesting strong stability and reusability. All the results demonstrated that Fe/LXQ-10 showed high potential and economic feasibility to remove gaseous toluene through adsorption and Fenton-like oxidation. This research not only presents a promising alternative for the effective removal of gaseous VOCs but also provides a theoretical basis in the field of VOCs control.

Polydimethylsiloxane (PDMS) Membrane for Separation of Soluble Toluene by Pervaporation Process.

A commercial polydimethylsiloxane (PDMS) membrane was employed to separate the soluble toluene compounds (C7H8) from an aqueous solution via the pervaporation (PV) process. The performance and the efficacy of the PDMS PV membrane were evaluated through the estimation of the permeation flux and separation factor under various operating parameters. The response surface method (RSM) built in the Minitab-18 software was used for the design of the experiment in this study, and the responses of the permeation flux and the separation factor were analyzed and optimized based on the operating conditions. A nonlinear regression analysis was applied to the experimental output and input, and as a result, a quadratic equation model with parameters interactions was obtained as mathematical expressions to predict the permeation flux and separation factor. At the optimal conditions of temperature 30 °C, initial toluene concentration 500 ppm, and feed flowrate 3.5 L/min, the toluene permeation flux and separation factor were 125.855 g/m2·h and 1080, respectively. The feed concentration was the most impactful and significant in the improvement of the permeation flux and separation factor of the PDMS membrane.

Synergistic mechanism of Ce-Mn in ZSM-5 carrier catalysts for catalytic oxidation of toluene

Volatile organic compounds (VOCs) are the main components of air pollutants, posing threat to the public health and the environment. In this study, a series of CeMnOx-ZF catalysts with different metal loadings were prepared from coal fly ash (CFA), and the optimal activation route of CFA to the synthesize carrier and the toluene catalytic oxidation effects by carrier catalysts were investigated. The synergistic mechanism of Ce and Mn metals in CeMnOx-ZF catalysts were investigated. The results showed that, CFA exhibited the highest activity under the pretreatment conditions of the 15% HCl mass fraction, 1.5:1 alkali/ash ratio, and 500℃ calcination temperature. Under optimized reaction conditions (600 ppm initial toluene concentration, 30000 h−1 GHSV, and 120-390℃ reaction temperature), 20 wt.% CeMnOx-ZF catalyst exhibited an extremely high toluene removal efficiency with the maximum of 99.6%. After water vapor introduction, the toluene degradation efficiency remained at a stable level, but CO2 yield increased. After 100-hour cycle test, the 20 wt% CeMnOx-ZF catalyst still exhibited a high toluene degradation efficiency (96.5%), indicating its high stability. This study provides a simple and convenient method for CFA activation and proposes a feasible strategy for designing and synthesizing high-efficiency catalysts for the degradation of VOCs.

Photocatalytic Removal of Toluene Vapour Pollutant from the Air Using Titanium Dioxide Nanoparticles Supported on the Natural Zeolite.

The emission of volatile organic compounds (VOCs) in industrial and urban areas has adverse effects on the environment and human health. Toluene, the main pollutant among the VOCs, has wide applications in different industries such as plastics, adhesives, silicone sealant, paint, etc. This study aimed to remove of toluene from the air by using TiO2 nanoparticles supported on the natural zeolite using the photo-catalytic process. This is an experimental study that was conducted in 2017 in the Chemical Agents Laboratory of the Occupational Health Engineering Department at Jundishapur University in Ahvaz. Toluene vapour decomposition was carried out using UV/ZE, UV/TiO2, and UV/TiO2-ZE under continuous flows conditions. The effects of toluene initial concentration, retention time, and nanocomposite surface weight on toluene vapour decomposition were also investigated. When UV/TiO2 and UV/TiO2-ZE systems are performed, increasing the initial toluene concentration reduces the efficiency of photocatalytic decomposition. The SEM images of TiO2-ZE catalyst show that zeolite pores were occupied by titanium dioxide nanoparticles. Moreover, the combination of titanium dioxide nanoparticles and zeolite has an incremental effect on toluene decomposition. Increasing retention time raises toluene decomposition, and the increased nanocomposite surface weight raises decomposition to the maximum level (70%) at 33.68 mg/cm2 weight and then decreases. The increasing toluene decomposition rate by using the TiO2-ZE nanocomposite can be due to the incremental effect of absorption and photocatalytic decomposition.

Experimental study on toluene removal by a two-stage plasma-biofilter system

Volatile organic compounds (VOCs) are typical pollutants that affect air quality. Discharge plasma is thought to be a potential method that can remove VOCs from flue gas. In this experiment, pulsed corona discharge plasma combined with a biological tower was carried out to remove the benzene series, and toluene was selected as the typical VOC. The results indicated that the removal efficiency of toluene by pulsed corona plasma was slightly higher than that of direct current (DC) corona plasma, while its energy efficiency was much higher than DC corona plasma. Under the optimal experimental conditions of pulse voltage 8.5 kV, initial toluene concentration 1400 mg m−3, and toluene flow rate of 12 l h−1, the toluene removal efficiency reached 77.11% by the single method of pulsed corona discharge plasma, and the energy efficiency was up to 1.515 g/(kW·h) under the pulse voltage of 4.0 kV. The trickling biofilter was constructed by using the screened and domesticated Acinetobacter baumannii, and the highest toluene removal efficiency by the pulsed corona discharge plasma combined with the trickling biofilter rose up to 97.84%. Part of the toluene was degraded into CO2, H2O, and some intermediate products such as o-diphenol under the influence of Acinetobacter baumannii. When the remaining waste gas passed through the discharge plasma reactor, the benzene ring structure could be directly destroyed by the collision between toluene and plasma. Meanwhile, O·, OH·, and some other oxidizing radicals generated by the discharge also join into the oxidative decomposition of toluene and its intermediate products, thereby further improving the removal efficiency of toluene. Therefore, the two-stage plasma-biofilter system not only showed a high toluene removal efficiency, but also had a good energy efficiency. The results of this study will provide theoretical support and technical reference for industrial VOC treatment.

Experimental analysis of gas- and particle-phase organic byproducts formed by plasma-induced toluene destruction processes

• Organic byproducts were evaluated by NTP degradation of toluene at ambient temperature and atmospheric pressure. • PTR-TOFMS measurement showed that toluene degradation resulted in dozens of organic by-products. • Size distribution and number concentration of particles formed during toluene degradation were measured by SMPS. • NTP-induced polymerization and oxidation contribute to particle formation with diameters in the range of 10 and 100 nm. Non-thermal plasma (NTP) technology has great potential to treat volatile organic compounds (VOCs) at low concentrations and large volumes. In this work, toluene, one of the most stable VOCs, was employed as a model pollutant to study its degradation by double dielectric barrier discharge (DDBD) at ambient temperature and atmospheric pressure. The performance of the DDBD reactor was evaluated in terms of discharge power, removal efficiency, CO x selectivity, and byproduct formation. Online and continuous measurements by PTR-TOFMS showed that toluene degradation resulted in the formation of 12 major volatile organic byproducts as well as 7 minor ones with concentrations ranging from ppbv to ppmv. Moreover, the particle size distribution and number concentration of particles formed during toluene degradation were measured using a scanning mobility particle sizer, and the effects of discharge power, initial toluene concentration, gas flow rate and O 2 content on particle formation were systematically investigated. The results show that both NTP-induced polymerization and oxidation contribute to aerosol formation, and the total concentration of organic byproducts in the aerosol phase is about 10 7 cm −3 with diameters in the range of 10 and 100 nm. This pioneered investigation on gas- and particle-phase organic byproducts from toluene degradation by NTP would deepen the understanding of plasma degradation of VOCs and accelerate the practical application of NTP for VOCs treatment.

Toluene Decomposition in Plasma–Catalytic Systems with Nickel Catalysts on CaO-Al2O3 Carrier

The decomposition of toluene as a tar imitator in a gas composition similar to the gas after biomass pyrolysis was studied in a plasma–catalytic system. Nickel catalysts and the plasma from gliding arc discharge under atmospheric pressure were used. The effect of the catalyst bed, discharge power, initial toluene, and hydrogen concentration on C7H8 decomposition, calorific value, and unit energy consumption were studied. The gas flow rate was 1000 NL/h, while the inlet gas composition (molar ratio) was CO (0.13), CO2 (0.15), H2 (0.28–0.38), and N2 (0.34–0.44). The study was conducted using an initial toluene concentration in the range of 2000–4500 ppm and a discharge power of 1500–2000 W. In plasma–catalytic systems, the following catalysts were compared: NiO/Al2O3, NiO/(CaO-Al2O3), and Ni/(CaO-Al2O3). The decomposition of toluene increased with its initial concentration. An increase in hydrogen concentration resulted in higher activity of the Ni/(CaO-Al2O3) catalysts. The gas composition did not change by more than 10% during the process. Trace amounts of C2 hydrocarbons were observed. The conversion of C7H8 was up to 85% when NiO/(CaO-Al2O3) was used. The products of the toluene decomposition reactions were not adsorbed onto its surface. The calorific value was not changed during the process and was higher than required for turbines and engines in every system studied.

Simulation of microwave electrodeless ultraviolet device and catalytic oxidation of toluene

AbstractIn order to improve the catalytic efficiency of toluene oxidation by heating catalyst and carrier in microwave single‐mode sintering furnace, the SJ‐1 microwave single‐mode sintering furnace is modified, and microwave electroless UV lamp is placed in the resonant cavity, and the catalytic efficiency of toluene is improved by using microwave electroless lamp in cooperation with microwave heating catalyst and carrier. In order to design the cavity, High‐Frequency Structure Simulator (HFSS) simulation is used to simulate it. The position of the waveguide, the position of the electroless UV lamp and its distance from the cavity center, and different input powers are simulated and analyzed, respectively. The electric field distribution diagram is obtained. According to the simulation analysis results, the waveguide on the left side, the cavity height of 300 mm, diameter of 160 mm aluminum alloy cavity is designed. The center of the lamp is 43 mm away from the center of the cylindrical cavity. The toluene catalytic efficiency is more than 94% at space speed of 6336.93 h−1, relative humidity of 50%, microwave input power of 455.6 W and initial toluene concentration of 60 ppm. It provides theoretical reference and guidance for the design of microwave electroless lamp thermal catalytic device.

Mn decorated UIO-66 catalyst for gaseous toluene removal: Synergistic effect of enhanced hydroxyl from H2O2

Gaseous toluene, one of the volatile organic compounds, has aroused wide concerns in China due to its growing emissions and harmfulness. Herein, novel manganese decorated UIO-66 catalysts (Mn/UIO-66) were prepared by hydrothermal synthesis and applied to the vaporized hydrogen peroxide system for toluene removal. TEM, BET, XRD, ICP, and XPS were used to analyze the chemical and physical characteristics of Mn/UIO-66. A toluene removal efficiency of 82% with the 3-Mn/UIO-66 catalyst in the vaporized hydrogen peroxide system could achieved. The effects of different reaction conditions (reaction temperature, hydrogen peroxide concentration, and initial toluene concentration) on toluene removal were determined. The yield of hydroxyl radical in the Mn/UIO-66 catalyst combined with the hydrogen peroxide system was positively correlated with the Mn decorated ratio. Results suggested that the catalytic performance is related not only to the yield of hydroxyl radical but also to the catalyst specific surface. The intermediate products during toluene removal were analyzed by gas chromatography-mass spectrometry (GC–MS), and the possible reaction pathway of toluene removal was proposed.

Nickel catalyst in coupled plasma-catalytic system for tar removal

Abstract Tar formation is a significant issue during biomass gasification. Catalytic removal of tars with the use of nickel catalyst allows to obtain high conversion rate but coke formation on catalysts surface lead to its deactivation. Toluene decomposition as a tar imitator was studied in gliding discharge plasma-catalytic system with the use of 5%, 10% and 15% by weight Ni and NiO catalyst on Al2O3 (α-Al2O3) and Peshiney (γ-Al2O3) carrier in gas composition similar to the gas after biomass pyrolysis. The optimal concentration of nickel was identified to be 10% by weight on Al2O3. It was stable in all studied initial toluene concentrations, discharge power while C7H8 conversion rate remained high – up to 82%. During the process, nickel catalysts were deactivated by sooth formation on the surface. On catalysts surface, toluene decomposition products were identified including benzyl alcohol and 3-hexen-2-one.

C-dot doping for enhanced catalytic performance of TiO2/5A for toluene degradation in non-thermal plasma-catalyst system.

Non-thermal plasma (NTP) is gaining attention as a powerful tool to induce various reactions. The combination of NTP with catalysts has been successfully used to degrade volatile organic compounds (VOCs) for pollution control. In this study, a series of TiO2-C/5A catalysts, synthesized by carbon dots (C-dots) that decorate TiO2 by sol-gel and wetness impregnation methods, were incorporated with a dielectric barrier discharge (DBD) reactor in a single-stage structure to degrade toluene at atmospheric pressure and room temperature. A proton-transfer reaction mass spectrometer and a CO2 analyzer were used to monitor the concentration variations of organic by-products and CO2 online. The effects of input power, mass ratio of C-dots/TiO2 (TiO2/5A (0 wt%), TiO2-C1/5A (2.5 wt%), TiO2-C2/5A (5 wt%), TiO2-C3/5A (10 wt%)), gas flow rate, initial concentration of toluene on the toluene degradation efficiency, and CO2 selectivity were studied. The plasma-catalyst hybrid system could effectively improve the energy efficiency and reaction selectivity, attaining a maximum toluene degradation efficiency of 99.6% and CO2 selectivity of 83.0% compared to 79.5% and 37.5%, respectively, using the conventional plasma alone. Moreover, the generation of organic by-products also declined dramatically, averaging only half as much in plasma alone. The results also indicated that the appropriate amount of C-dot doping could greatly improve the catalyst efficiency in the hybrid plasma system. This is because the interaction between C-dots and TiO2 favors the formation of photoelectron holes and reduces the energy band gap and the recombination rate of photogenerated electron holes, which facilitates the generation of more active species on the catalyst surface, thereby leading to a more effective degradation reaction. These observations will provide guidance for the interaction studies between NTP and catalysts, not only for the exploration of new chemical mechanisms of aromatic compounds, but also for the screening of favorable materials for the desired reactions.

Simulation of irradiation intensity distribution of electrodeless ultraviolet lamp in cylindrical resonator by CFD

To improve the catalytic efficiency of the microwave single-mode sintering furnace to heat the catalyst and the carrier to catalyse the oxidation of toluene, the SJ-1 microwave single-mode sintering furnace was modified to place a microwave electrodeless ultraviolet lamp in the resonant cavity. The distribution of pollutants in the reactor and the intensity of UV light were calculated by CFD and visualized. The distribution of UV field can be seen from the results of light field, which provides a scientific basis for the placement of catalyst and a reference for the simulation of UV field. Under the conditions of relative humidity of 50%, space velocity of 6336.93 h−1, input power of 392.8 W, bed height of manganese oxide catalyst is 30 mm, initial toluene concentration of 235.23 mg/m3, input power of 595.3 W, toluene conversion efficiency of 94%. It has certain guiding significance.

Designing of biodegradable polycaprolactone: Binary and ternary coatings to minimize the defects and cost of solvent(s)

AbstractCoatings of polycaprolactone (PCL) in methylene chloride and toluene were prepared using solution casting method. Coatings of two different polymer mass percentages (5% and 10%), and thicknesses (800 and 1600 μm) were prepared. A drying study on PCL‐methylene chloride‐toluene coatings was carried out. The binary coatings of PCL‐methylene chloride and PCL‐toluene served as control cases. The results showed that the drying behavior was external mass transfer controlled for the binary coatings but diffusion controlled for the ternary coatings for most of the drying period. The drying rate enhanced but residual solvent increased with the progressive increase in initial concentration of methylene chloride and decrease in initial concentration of toluene. This shows that the drying rate can be enhanced by partially replacing the costly solvent with cheaper one, that is, toluene with methylene chloride. The coatings were characterized by scanning electron microscopy to understand the surface morphology. The scanning electron microscopy results further indicate that replacing toluene with methylene chloride caused disappearance of cracks, wrinkles, and phase‐separation. The coatings with high initial content of methylene chloride were smooth and dense, and more residual solvent content does not manifest in coating defects. Hence, replacement of toluene with methylene chloride leads to savings on material and energy costs for drying along with better quality coatings.