Acetate Removal Research Articles

Accelerated removal of solvent residuals from PLGA microparticles by alcohol vapor-assisted fluidized bed drying

The removal of residual solvents from biodegradable poly(D,L-lactide-co-glycolide) (PLGA) microparticles by fluidized bed drying was investigated. Microparticles were prepared by the O/W solvent extraction/evaporation method and the influence of various process and formulation parameters on the secondary drying was studied. PLGA microparticles and films were characterized for residual organic solvent and water content, recrystallisation, surface morphology, drug loading and in-vitro release of the drugs dexamethasone and risperidone. While alcohol-free fluidized bed drying decreased the residual dichloromethane content only from about 7 % (w/w) to 6.4 % (w/w) (18 °C) or 3.2 % (w/w) (35 °C) within 24 h, 140 mg/L methanol vapor in purge gas facilitated almost complete removal of dichloromethane or ethyl acetate from microparticles (0–0.11 % (w/w) after 6 h). By controlling the alcohol concentration and temperature of the purge gas, the alcohol absorption and complete removal was controlled. Risperidone increased the methanol absorption enhancing the plasticization. A high initial residual water content was identified to promote aggregation and was eliminated by starting fluidized bed drying without alcohol. Alcohol vapor-assisted fluidized bed drying accelerated microparticle manufacturing without affecting the redispersibility, the drug loading and the in-vitro release of risperidone and dexamethasone.

Unveiling the synergism and reaction pathway of ethyl acetate removal in DBD/absorption integrated reactor

The experiment employs dielectric barrier discharge (DBD) combined with absorption integrated reactor (DCAIR) for higher concentration ethyl acetate removal and studies the synergism of DCAIR technology and the reaction pathway of ethyl acetate. Among three technologies of DCAIR, DBD and DBD combined with absorption series reactor (DCASR), DCAIR achieved the highest removal efficiency (RE) of ethyl acetate at similar input power. Fixed gas flow rate of 1000 ml/min and cC4H8O2in of 5000 mg/m3, the average REs of DCASR and DCAIR are higher than that of DBD by 31.2 % and 34.2 %, respectively. For the efficiency compensation mechanism, one of synergies in DCAIR, RE of ethyl acetate could exceed 80 % at the input power of 15 W. Energy consumption evaluation shows when RE > 80 %, the max energy efficiency of three technologies is in the order 70.0 g/kWh (DCAIR) > 5.1 g/kWh (DCASR) > 3.0 g/kWh (DBD). Tail gas and absorbent analysis reveals DCAIR can enhance mineralizing ethyl acetate and eliminating the secondary pollutants (e.g., O3, gaseous organic intermediates, and COD, etc.) effectively, due to its special structure of reactor. According to FT-IR spectra, the degradation mechanism and reaction pathway of ethyl acetate in DCAIR has been unveiled.

Highly efficient degradation of ethanol, acetaldehyde, and ethyl acetate removal by bio-trickling filter reactors with various fillers

This study investigates the purification performance of bio-trickling filters (BTFs) using different media to treat ethanol, acetaldehyde, and ethyl acetate in kitchen waste malodorous gases. The media compared included a custom composite medium, pine bark, hollow polyhedral spheres, and ceramic particles. Over 25 days, the composite medium outperformed the traditional media, achieving removal rates of 90.13 % for ethanol, 63.89 % for acetaldehyde, and 82.56 % for ethyl acetate during the biofilm initiation phase, with the others below 60 %. Even under low empty bed residence time and high inlet concentrations, the maximum elimination capacity for ethanol, acetaldehyde, and ethyl acetate was 8.34–14.70 g/m3·h, 9.55–15.06 g/m3·h, and 6.18–10.45 g/m3·h. Kinetic analysis showed the Michaelis-Menten model fit well, indicating enhanced removal potential. High-throughput of 16S rDNA sequencing identified dominant microorganisms like Enterobacteriaceae (13.89 %), Stenotrophomonas (29.23 %), and Acinetobacter (4.09 %) in the composite medium, which thrived even at high pollutant concentrations. Principal component analysis (PCA) demonstrated differences in the microbial composition of the custom composite medium compared to traditional media under varying inlet concentrations and loads. This study provides technical support for the treatment of complex malodorous gas mixtures.

Simultaneous removal of microorganisms and ethyl acetate from fruit storage indoor air using a low-cost photoreactor based on luminous textiles

Escherichia coli (E. coli), Salmonella typhimurium (S. typhimurium), Listeria monocytogenes (L. monocytogenes), and Cladosporium cladosporioides (C. cladosporioides), as microorganisms, and ethyl acetate (EA), as a volatile organic compound, were chosen as target pollutants to be removed from indoor air. The E. coli degradation was firstly investigated. Second, the simultaneous degradation of all studied microorganisms was assessed. Third, a separate investigation was conducted for EA. These investigations focused on the antibacterial and photocatalytic behaviors of the TiO2, Ag/TiO2, and Cu/TiO2 luminous textiles. Compared to other photocatalysts, the Cu/TiO2, exhibits the highest bacterial disinfection and EA removal. Fourth, simultaneous degradation of E. coli and EA was assessed with the most efficient photocatalyst. The Cu/TiO2 catalyst proved to be efficient by inactivating 4.72log of E. coli, 5.18log of S. typhimurium, 4.76log of L. monocytogenes, and 0.61log of C. cladosporioides, at the same time. The performance of the Cu/TiO2 catalyst can be assigned to the intrinsic conduction band and valence band positions of CuO, Cu2O, and TiO2. Using the Cu/TiO2 photocatalyst, a bacterial inactivation of 3.63log and an EA degradation efficiency of 91.13% were obtained within 60 min of UV light irradiation. It was unequivocally established that E. coli's presence inhibited the removal of EA (reducing from 91.13% to 65.97%), which can be attributed to the humidity effect and the competition reactions of the photocatalyst among E. coli, EA, and EA by-products. The bactericidal inactivation was equivalent to 3log for E. coli, but it increased to 4log for the E. coli/EA mixture. The damage caused to bacteria proteins by the by-products of EA was the reason for this outcome. The explanation for E. coli inactivation and EA photodegradation on Cu/TiO2 luminous textiles is discussed. The low-cost configuration of a luminous textile photocatalyst used showed a superior performance for the simultaneous elimination of E. coli and EA from indoor air in a modular and low-cost photoreactor.

An extended bio-electrochemical model for wastewater treatment and water desalination: Insights into the performance of microbial desalination cells

This paper presents an extended mathematical model for a microbial desalination cell (MDC), integrating Haldane kinetics for substrate inhibition and proton translocation theory for substrate dissociation under dynamic flow. The model is capable of predicting exoelectrogenic and methanogenic biomass dynamics, acetate removal efficiencies, salt concentration changes, and current production. Notably, it can be used to explore the influence of operational parameters such as dilution rates, temperatures, and external resistances. Our simulations reveal the optimal conditions for maximizing exoelectrogen concentration (500 mg/L) with minimal methanogen presence (50 mg/L) in the anode chamber at an anolyte dilution rate of 0.5 d−1, a temperature of 20 °C, and an influent acetate concentration of 1500 mg/L. The model accurately predicts the salt reduction in the middle chamber (from 0.2 to 0.09 mol/L) with a salt dilution rate of 0.5 d−1 and an external resistance of 20 Ohm. The model predicts a peak power output of 2.5 mW at external resistances between 20 and 50 Ohm. The model was validated against a suite of experimental literature data, including our previously published lab-scale studies, verifying its accuracy in predicting organic and salt removal rates, current production, and desalination efficiency. This extended model is a valuable tool for understanding the complex interactions between factors that influence MDC performance and can guide the optimization of MDC design for wastewater treatment and desalination.

Removal of butyl acetate in an industrial ef uent through a physicochemical treatment

Butyl acetate is an organic compound widely used in industry, focu- sing on industrial paint waste ef uents. Exposure to this pollutant at an average of 925 ppm can cause dizziness, drowsiness, respiratory tract irritation, and central nervous system suppression. That is why it seeks to minimize the risk associated with this contaminant through treatment alternatives. The characterization of the sample yielded the detection of the following contaminants: methyl ester, 1-butanol, 1-4 dioxane, butyl ester, 1-chlorobutane. The objective of this work was the design and development of combined treatments for the removal of butyl acetate in industrial waste ef uents. For this, a physicoche- mical treatment coupled to an advanced oxidation process (PAO) was implemented. The results showed that the coupled treatments are ef - cient for the removal of butyl acetate, methyl ester, 1-chlorobutane and 1-butanol, while for 1-4 dioxane it was reduced by approximate- ly 83%. The study was complemented with the evaluation of the fo- llowing parameters, resulting in a decrease in electrical conductivity of 99.5%, total suspended solids of 74%, color of 93%, turbidity of 55% and COD of 73%.

Insights into effects of grain boundary engineering in composite metal oxide catalysts for improving catalytic performance

Volatile Organic Compounds (VOCs) have long been a threat to human health. However, designing economical and efficient transition metal composite oxide catalysts for VOCs purification remains a challenge. Herein, this study demonstrates the enormous potential of grain boundary engineering in facilitating VOCs decomposition over ordered mesoporous composite oxide denoted as 3D-MnxCoy (x, y = 1, 3, 5, 7, 9). Specifically, the three-dimensional (3D) Mn7Co1 catalyst shows 100% ethyl acetate removal efficiency for a continuous airflow containing 1000 ppm ethyl acetate over 60000 h−1 space velocity at 160 °C. Mechanism study suggests that the high catalytic performance originates from the lattice distortion caused by the introduction of heteroatoms, along with the size effect of nanopore walls, which leads to the formation of various grain boundaries on the catalyst surface. The presence of grain boundaries facilitates the generation of oxygen vacancies, thus promoting the migration and activation of oxygen species. Furthermore, the near-atmospheric pressure X-ray photoelectron spectroscopy (NAP- XPS) monitoring results reveal that the bimetallic synergy enhanced by grain boundary accelerates the catalytic reaction rate of VOCs through Mn3++Co3+↔Mn4++Co2+ redox cycle. This study may shed light on the great potential of ordered mesoporous bimetallic oxide catalysts in VOCs pollution control.

Chemical method for ethyl vinyl acetate removal in crystalline silicon photovoltaic modules

To recycle silicon from solar panels is required to remove the Ethyl Vinyl Acetate (EVA) encapsulant. Thermal methods produce gas emissions. Chemicals, such as toluene dissolve EVA but the process can take days. Here an alternative method to detach EVA from the solar cell is reported. After removing the glass and backsheet, the solar cell and the solvent were immersed in the thermal water bath. We evaluated three solvents (hexane, benzene, and toluene) at different temperatures and times. Better results were obtained using toluene; the process was optimized using 80 °C of temperature and 120 min. The method could remove 72% of the EVA from the solar cell. We also measured the effect of four scrapped grain sizes, having the best results with particles smaller than 0.86 mm.

Removal of encapsulant Ethylene-vinyl acetate (EVA) from solar cells of photovoltaic modules (PVMs)

Photovoltaic modules (PVMs) are a very promising way to meet future energy needs. As traditional energy sources aren't sustainable, the only way to meet future energy needs will be through renewable energy sources. The amount of e-waste expected to generated in the near future is an important concern. Ethylene-vinyl acetate (EVA) encapsulatethe solar cell, and this layer must be removedto get to the other materials that can be recycled. EVA can be removedwith the help of heat treatmentand organic solvents. In this work, the interaction of EVA with different organic solvents was studied. For measuring interaction, the swelling of EVA caused by the organic solvent penetrating andaccommodatinginsidethe polymer matrix is considered. The swelling also caused EVA to lose its mechanical strength, making it easy to remove. The reaction of organic solvents with EVA is explained in terms of functional groups of organic solvents. When compared to other solvents, chlorinated hydrocarbons such as trichloroethylene, carbon tetrachloride, chloroform can effectively cause EVA swelling. Furthermore, aromatic hydrocarbons interact well with EVA. Aromatic hydrocarbons are relatively better choice than chlorine-containing hydrocarbon for industrial application based on sustainability of the process.

Introducing cerium into TiO2@MnOx hollow-sphere structure for highly active photothermocatalysis degradation of ethyl acetate and NO under H2O at low temperature

The CeO2-TiO2@MnOx catalyst was prepared by the co-precipitation method and applied to the photothermocatalysis system of ethyl acetate and NO simultaneous degradation under H2O at low temperature, which introduced Ce into TiO2@MnOx hollow sphere structure. The optimum TiO2/MnOx ratio and Ce introducing amount were obtained in the process. Among of them, the NO and ethyl acetate conversion percentage of TiO2@MnOx (nMn:nTi = 40:40) is 74% and 62% at 240 °C, respectively. CeO2-TiO2@MnOx (nMn-Ti:nCe = 1:1) exhibits the best catalytic performance, its efficiency for NO conversion is 83% and the conversion of ethyl acetate reaches 72% at 240 °C. In addition, it is confirmed that the Ce-doped nanocomposites have more uniform dispersion through various characterization and analysis methods. Meanwhile, these catalysts have a large specific surface area as well as a large number of surface-active oxygen and oxygen vacancies. It can further improve the catalytic performance based on the adjusted ratio of active components. Moreover, this work investigated the relationship between multi-metal interactions and catalytic performance in the presence of H2O. Finally, the possible reaction pathways for the simultaneous removal of NO and ethyl acetate were explored in our system.

Pt/CeMnOx/Diatomite: A Highly Active Catalyst for the Oxidative Removal of Toluene and Ethyl Acetate

Pt nanoparticles and a CeMnOx composite were loaded on the surface of the natural diatomite material to generate the Pt/CeMnOx/diatomite using the redox precipitation and impregnation methods. The physicochemical properties of the catalysts were characterized by means of various techniques. The catalytic properties and resistance to H2O and SO2 of the catalysts were measured for the oxidation of typical volatile organic compounds (i.e., toluene and ethyl acetate). Among all of the as-prepared samples, Pt/CeMnOx/diatomite exhibited the highest catalytic activity: the temperatures (T90%) at a toluene or ethyl acetate conversion of 90% were 230 and 210 °C at a space velocity (SV) of 20,000 mL g−1 h−1, respectively, and the turnover frequency (TOFPt) at 220 °C was 1.04 μmol/(gcat s) for ethyl acetate oxidation and 1.56 μmol/(gcat s) for toluene oxidation. In particular, this sample showed a superior catalytic activity for ethyl acetate oxidation at low temperatures, with its T50% being 185 °C at SV = 20,000 mL g−1 h−1. In addition, the Pt/CeMnOx/diatomite sample possessed good sulfur dioxide resistance during the toluene oxidation process. In the presence of SO2, some of the SO2 molecules were adsorbed on diatomite, which protected the active sites from being poisoned by SO2 to a certain extent. The pathways of ethyl acetate and toluene oxidation over Pt/CeMnOx/diatomite or Pt/CeMnOx were as follows: The C–C and C–O bonds in ethyl acetate are first broken to form the CH3CH2O* and CH3CO* species or toluene is first oxidized to benzaldehyde and benzoic acid, and all of these intermediates are then converted to CO2 and H2O. This work can provide a strategy to develop efficient catalysts with high catalytic activity, durability, low cost, and easy availability under actual working conditions.

An optimized acidic digestion for the isolation of microplastics from biota-rich samples and cellulose acetate matrices

Plastic pollution is a growing concern. To analyze plastics in environmental samples, plastics need to be isolated. We present an acidic/oxidative method optimized to preserve plastics while digesting synthetic cellulose acetate and a range of organics encountered in environmental samples. Cellulose acetate was chosen for optimization as it can be purchased as a reference material, can co-occur with plastics in environmental samples and, if it can be completely digested, is a potential filter material for the collection of nano- and micro-plastics from natural waters. Other forms of particulate organic matter (POM) were chosen to provide a range of chemistries that might alter digestion efficiency and due to the interest in the community of isolating plastics from samples where these organics occur. For instance, microalgal POM occurs in lake and ocean waters, riverine POM in rivers, and inclusion of tuna provides a test for the suitability of the method for isolating plastics from animal tissues. The method is a one-pot overnight (16–18 h) digestion in 5 M nitric acid with 0.3 M sodium persulfate heated to 80 °C. The method provides quantitative removal of cellulose acetate (exceeding detection limits), near quantitative removal of microalgal POM and Albacore tuna tissue (>99%), but only 86% of urban river POM, all while retaining >99% by mass of C–C bonded polymers polyethylene, polypropylene, and polystyrene and >96% by mass of polyethylene terephthalate. Fourier transform infrared spectroscopy (FT-IR) and %-C content analysis confirmed plastic polymer stability during digestion. However, some additives in appear susceptible to digestion with FT-IR results indicating the loss of N,N′-ethylenebis(stearamide) from polyethylene. This method provides a simpler and more effective method than many in the literature. We present recommendations for the application of this method, as well as limitations and areas for future improvement.

Coagulation characteristic and mechanism of Fe(III) salts toward typical Cr(III) complexes in wastewater treatment.

Cr(III) complexes are typical pollutants in various industrial wastewater and pose a serious threat to the ecosystem and humans. The coagulation process is commonly used in water treatment plants, yet its removal characteristic and mechanism toward Cr(III) complexes have been rarely reported. In this study, the Fe(III) coagulation process was adopted for the evaluation of Cr(III) complex removal in terms of Cr residual concentration as well as floc size. The results showed that Fe(III) with a dose of 0.8mM removed more than 80% of total Cr for Cr3+ and Cr(III)-acetate, whereas poor removal rate (~ 50%) was obtained for Cr(III)-citrate under the same conditions. Neutral and alkaline conditions facilitated Cr(III)-acetate removal by Fe(III) coagulation, while limited influence was observed for Cr(III)-citrate with various pH. The main removal mechanism of Cr(III)-acetate was precipitation. Cr(III)-citrate elimination largely relied on the adsorption property and sweeping effect of Fe floc. Moreover, Cr(III)-acetate was easier to be separated from a solution since the generated floc sizes were 270μm. Flocs that formed in the Cr(III)-citrate treatment were only 0.3μm, resulting in separation difficulties during the coagulation process. The presence of Cr(III)-acetate and Cr(III)-citrate caused a significant decline in membrane flux. This study provided fundamental knowledge of Fe coagulation treatment in Cr(III) complex-containing wastewater.

Birnessite MnO2 supported on CNTs in-situ for low-temperature oxidation of ethyl acetate

The removal of ethyl acetate has received much attention because excessive emissions of ethyl acetate are harmful to the environment and human health. Efficiently removing ethyl acetate under high space velocity requires low-cost catalysts operating at low temperatures. Herein, carbon nanotubes (CNTs) supported birnessite MnO2 catalysts were in-situ prepared by the redox reaction between KMnO4 and CNTs to maximize the interaction between MnO2 and support. The good thermal stability derived from the intact CNTs structure was important for the interaction between MnO2 and CNTs, contributing to the enhanced catalytic activity for ethyl acetate oxidation. 4MnO2-CNTs showed outstanding performance for the catalytic oxidation of ethyl acetate (100 ppm), achieving 100% removal efficiency and 99% CO2 selectivity at 160 °C under 100,000 mL·g−1·h−1 space velocity. In addition, 4MnO2-CNTs exhibited an excellent catalytic stability during the 50 h test period. Based on the comprehensive characterization study, we revealed that the activity of 4MnO2-CNTs could be effectively enhanced by the higher amount of active sites (Mn3+ and surface active adsorbed hydroxyl oxygen), as well as the strong interaction between MnO2 and support and the good thermal stability derived from the introduction of the intact CNTs structure.

Photothermal synergistic catalytic oxidation of ethyl acetate over MOFs-derived mesoporous N-TiO2 supported Pd catalysts

To overcome the main challenge of low photocatalytic efficiency and high energy consumption of thermocatalysis in the oxidation of volatile organic compounds (VOCs), MOF-derived mesoporous disk-like yPd/xN-TiO2 (x = 3.2, 5.5, 7.7 wt%, and y = 0.26 wt%) were prepared by ball milling-calcination method for photothermal catalytic oxidation of ethyl acetate. Morphological and pore structure characterization indicated that Pd/N-TiO2 had abundant pore structure and large specific surface area, which facilitated the adsorption of pollutants on the active sites. Among the catalysts, 0.26 Pd/3.2 N-TiO2 exhibited optimal photothermal catalytic performance. The corresponding temperature required for 50% and 90% conversion of ethyl acetate was 192 and 212 °C, with the specific reaction rate of 0.95 µmol/(gPd s) at 150 °C. Doping of N and loading of Pd nanoparticles enhanced the light absorption capacity, promoted the charge separation, and the adsorption capacity of ethyl acetate, resulting in a high photothermal catalytic oxidation activity. The detection of free radicals indicated that the photothermal synergy was associated with the generation of reactive oxygen species over 0.26 Pd/3.2 N-TiO2 under light irradiation condition, which directly participated in the catalytic removal of ethyl acetate. A proper increase in temperature could also promote the migration of carriers. The photothermal catalytic oxidation of VOCs over MOF-derivatives had great potential application for environmental protection.

Highly active nanostick-assembled TiO2@MnOx hollow-sphere structure for photothermocatalysis of ethyl acetate and NO with free-ammonia at low temperature: Resistence, key reaction steps and mechanisms

In this work, a series of self-assembled nanosticks into hollow-sphere structure of TiO2-MnOx (H1 sample), TiO2@MnOx (H2 sample) and MnOx@TiO2 (H3 sample) catalysts were successfully established. These samples were used to investigate the resistance to SO2 and H2O, key reaction steps, and the possible catalytic mechanisms for the photothermocatalytic removal of ethyl acetate and NO with free-ammonia at low temperature. Among all the samples, sample H2 exhibited the best catalytic activity, which exhibited 70% NO conversion and 56% ethyl acetate degradation at 240 ℃ under SO2 and H2O. The catalyst was resistant to SO2 and H2O and potentially benefited from the hollow structure’s protection of active components. Moreover, the sample H2 loaded first with manganese and then with titanium, was favorable for the oxidation of ethyl acetate into small-molecule intermediates, thereby improving NO conversion. This indicated that the partial oxidation of ethyl acetate as the reductant for NO conversion was a key step of the simultaneous degradation of VOCs and NO. In addition, organic by-products of ethyl acetate and NO degradation, such as ethane and ethanol, were found. Finally, the theoretical results of Density Functional Theory (DFT) calculations revealed that ethyl acetate was more easily converted into CH3CH2· and CH3COO· groups in our system.

Deacetylation kinetics of promising energy crops, hemp and kenaf, for cellulosic ethanol production

AbstractLignocellulosic hydrolysates contain acetic acid derived from hemicellulose. Acetate released during acid pretreatment interferes with enzymatic saccharification of the biomass and inhibits yeast fermentation, caused by cellular oxidation and stress. This study used alkaline deacetylation prior to acid pretreatment and evaluated its influence on the fermentation performance of Saccharomyces cerevisiae using two different lignocellulosic biomasses, hemp (Cannabis sativa) and kenaf (Hibiscus cannabinus). They are valuable for biofuel production. The maximal acetate removal with minimal sugar loss was obtained with 1% (w/v) NaOH treatment for both biomasses. Deacetylation pretreatment under this condition was effective both in enzymatic saccharification and simultaneous saccharification and fermentation. This resulted in improved ethanol production by xylose‐consuming yeast (S. cerevisiae SR8) by removing 4.7 g/L of acetate from hemp and 6.3 g/L from kenaf, thus resulting in the ethanol productivities of 0.79 and 0.67 g/L‐h from hemp and kenaf, respectively. This suggests that strategies to overcome acetate inhibition are necessary to efficiently use the lignocellulosic biomass as a source for bioenergy production.

Pollution and Cleaning of PDMS Pervaporation Membranes after Recovering Ethyl Acetate from Aqueous Saline Solutions

The removal of volatile organic compounds (VOCs) from wastewater containing nonvolatile salts has become an important and interesting case of the application of the pervaporation (PV) process. The aim of this study was to evaluate the influence of salts on the PV removal of ethyl acetate from wastewater using a polydimethylsiloxane (PDMS) membrane. The fouled membrane was then characterized via scanning electron microscopy–energy-dispersive X-ray analysis (SEM–EDX) to investigate salt permeation. The membrane backflushing process was carried out by periodically flushing the permeate side of the tubular membrane. The results demonstrated that salts (NaCl and CaCl2) could permeate through the PDMS membrane and were deposited on the permeate side. The presence of salts in the feed solution caused a slight increase in the membrane selectivity and a decrease in the permeate flux. The flux decreased with increasing salt concentration, and a notable effect occurred at higher feed-salt concentrations. A permeate flux of up to 98.3% of the original flux was recovered when the permeation time and backflushing duration were 30 and 5 min, respectively, indicating that the effect of salt deposition on flux reduction could be mitigated. Real, organic, saline wastewater was treated in a pilot plant, which further verified the feasibility of wastewater PV treatment.

High-throughput volatile organic compounds removal in a sandwich-type honeycomb catalyst system combined with plasma

This paper reports on the ethyl acetate (EA) removal over a honeycomb catalyst using an experimental design methodology. A mathematical model based on the response surface methodology is developed to evaluate the effect of parameters such as specific input energy (SIE), humidity, and EA concentration on the response variables (i.e., removal and energy efficiency). A set of experiments based on a statistical three-level full-factorial design of the experimental method were performed to collect the removal data. The model (R12 = 0.9858 and R22 = 0.9305 for removal and energy efficiency, respectively) indicates a satisfactory correlation between the experimental and predicted values. The analysis results using the model show that SIE is the principal parameter affecting the EA removal. Besides, verification of the experimental results indicates that the EA removal of 90.93% and the energy efficiency of 2.91g.kWh−1 at 235 J L-1, 1.5%, and 30.3 ppm were achieved under optimal conditions.

Degradation of enrofloxacin in aqueous by DBD plasma and UV: Degradation performance, mechanism and toxicity assessment

Enrofloxacin (ENRO) as a highly toxic antibiotic poses great threats to human health and environmental safety. In this study, a novel technology of coupling dielectric barrier discharge (DBD) and ultraviolet (UV) was investigated to efficiently degrade ENRO in aqueous, and had a higher degradation rate. The ENRO degradation rate achieved approximately 93.9% at 30 min, and approximately 1.20 g kWh−1 of energy yield (G50) was observed for the combined system. The addition of H2O2 and K2S2O4 improved the ENRO degradation due to the generation of ·OH and ·SO42-. In the presence of NO3–, the ENRO degradation played a tendency to promote first and then decrease, and the presence of SO42- resulted in the positive effect, while the negative effect was shown in the presence of Cl- and CO32–. The trapping experiment indicated that ·OH played an important part in the ENRO degradation. The addition of UV into the DBD system decreased H2O2 concentration in deionized water, and increased ·OH concentration. The DFT analysis showed the degradation mechanisms of ENRO at a molecular level. The degradation of ENRO mainly involved the oxidation of the piperazine group, the removal of ethyl acetate and the substitution of the F atom. The toxicity of ENRO and its degradation intermediates was evaluated.