Pyrolysis characteristics and product distribution of oil sludge based on radiant heating.

It needs to be improved the conversion efficiency and stable operation of conventional pyrolysis with high-temperature flue gas heating (HFH). Herein, a new radiative heating (RH) pyrolysis method is proposed. Experimental studies are carried out on a self-made radiation pyrolysis pilot plant to investigate the effects of different factors (pyrolysis final temperature, residence time, and carrier gas volume) on product distribution. The results show that with the increase of pyrolysis temperature, the yield of the gas phase consistently increases, and the proportion of CH4 and H2 in the pyrolysis gas reaches 62.31% at 700 °C. The yield of the liquid phase increases and then decreases. The recovery rate of pyrolysis oil achieves 68.07% when the pyrolysis temperature is 600 °C with main components of ketones and unsaturated hydrocarbon compounds. The yield of the solid phase consistently decreases. The RH in this work generates more pyrolysis gas in the pyrolysis process and alleviates the effects of fouling layers on the continuous operation of the equipment which has guiding significance for the efficient resource utilization of oil sludge.

Highly efficient carbonation and dechlorination using flue gas micro-nano bubble for municipal solid waste incineration fly ash pretreatment and its applicability to sulfoaluminate cementitious materials.

Cement production is a primary source of global carbon emissions. As a hazardous waste, municipal solid waste incineration fly ash (MSWI-FA) can be pretreated as a cementitious and effective carbon capture material. This study proposes an efficient carbonation dechlorination pretreatment and resource recovery strategy using flue gas micro-nano bubble (MNB) to wash MSWI-FA. The results showed that the flue gas MNB water washing reaction solution inhibited CaCO3 boundary layer blocking and adsorption on NaCl and KCl leaching. Under low water-to-solid ratio and CO2 concentration conditions, two-step washing reduced the MSWI-FA chlorine content to <1%, improving the dechlorination effect by 19.72% compared to conventional carbonation. The flue gas MNB water accelerated the precipitation of Ca2+ and Ca(ClO)2 in the form of calcite. The higher the CO2 concentration in the flue gas MNB, the better the fragmentation and purification of the MSWI-FA shell, leading to improved dechlorination and CO2 fixation. Under optimized conditions, the mean particle size of MSWI-FA decreased by 47.82%, and the CO2 fixation rate reached 73.80%, with a 58.35% increase in the washing carbonation rate. MSWI-FA pretreated by flue gas MNB washing was used as both the raw material and supplementary cementitious material for sulfoaluminate cementitious (SAC) material, exhibiting excellent compressive strength and heavy metal stabilization. The maximum compressive strength of the MSWI-FA-based SAC material cured for 28 d reached 130 MPa. Cr leaching was inhibited with increased hydration time, and the leaching concentration was far below the standard limit.

Bidirectional Catalysis Disintegration and Mineral Polymerization via Endogenous Iron(III) from Iron-Rich Sludge in Synergy with Waste Incineration Fly Ash.

To enhance the utilization of solid waste in cement kiln co-processing, this study analyzed the multifaceted synergy of pyrolysis and mineralization processes of iron-rich sludge (SS) and waste incineration fly ash (FA) at optimal blending ratios. Based on the physicochemical properties of SS and co-pyrolysis experiments, it was found that Fe acted as a positive catalyst in pyrolysis between 700 and 1000 °C, while the endogenous polymerization effect of Fe(III) mineral groups dominated above 800 °C. Additionally, the study investigated the solidification and migration of heavy metals and the transformation of harmful elements (S, Cl, and P). Results indicated that the best mixture ratios for SS and FA were 6:4 and 9:1, respectively, and synergistic pyrolysis and mineral co-curing effects were observed in the pyrolysis temperature range of 50-1000 °C. The synergy between SS and FA allowed for the decomposition and solidification of harmful organic components and heavy metals, reducing environmental risks. Furthermore, in actual production, by mixing 100 tons of SS and FA with Portland cement with a daily output of 2500 tons, the compressive strength during early hydration stages can reach 34.52 MPa on the third day, exceeding the highest performance of Portland cement (62.5R) strength index specified in the standard.

Calcination of sewage sludge-based sulphoaluminate cement clinker: Mineral formation mechanism and heavy metal transition behaviors.

Utilizing sewage sludge (SS) to calcinate sulphoaluminate cement (SAC) is a promising technology for low-carbon transition of cement industry, but the unclear effects of SS-contained heavy metals limit the application of this technology. In this study, the effects of SS addition on the calcination of SAC clinker and the transformation of heavy metals were studied from the aspects of mineral phase change, microstructure evolution and heavy metal speciation respectively, covering the mineral formation temperature 900-1250 °C. The results show that the added SS will reduce the formation temperature and change the reaction pathways of mineral phases. When the content of SS increases from 10% to 25%, the compositions of mesophases CaO·Al2O3 and 4CaO·2SiO2·CaSO4 increase by 6.33% and 9.73%, respectively. Meanwhile, the formation of minerals will solidify Zn, Ni, Mn, Cu, Cr, and convert them into a more stable fraction (residual fraction), indicating a lower probability to harm the environment. Moreover, heavy metals present different migration behaviors. After calcination, Mn migrates from SS to 4CaO·Al2O3·Fe2O3 (52.48%), while Zn prefers to enter 3CaO·3Al2O3·CaSO4 (43.74%) and 4CaO·Al2O3·Fe2O3 (38.06%). This study offers new insights into the mineral formation mechanism and heavy metal transition behaviors of sewage sludge-based SAC.

Insights into the underpinning effect of graphene in Cu1Mn10 on enhancing the low-temperature catalytic activity for CO oxidation.

CO emission is a critical issue of industrial processes such as steel-smelting, cement manufacturing, and waste incineration. Catalytic oxidation based on Cu-Mn binary catalysts shows great potential for efficient removal of CO, whereas their practical applicability is limited by the inferior low-temperature catalytic activity and the high catalyst cost owing to a substantial quantity of Cu. In this study, doping graphene is designed to adjust the electron transfer capability to improve the low-temperature catalytic activity as well as reduce the amount of Cu, and thereby Cu1Mn10 catalysts doped with slight amounts of graphene (x%G-Cu1Mn10, x is 1∼5) were fabricated. It was found that the introduction of graphene could form effective electron transport channels to enhance the intermetallic interaction and oxygen vacancy generation, thus improving the low-temperature catalytic performance of the Cu1Mn10 catalyst. Among all the catalysts, 4%G-Cu1Mn10 exhibited the highest activity, achieving CO conversion of 92% at 110 °C at a weight hourly space velocity of 120,000 mL/(g∙h). The introduction of graphene also enabled the catalyst with excellent catalytic activity and stability at a relative humidity of 70%. Attractively, 4%G-Cu1Mn10 can be further loaded into the polyester fabric, presenting great application potentials in the effective elimination of CO during the dust removal process since the flue gas temperature in the dust collector is just around the T90% and the catalyst that is inside of fabric fiber rather than on the fabric surface can be rarely influenced by the dust. In general, doping graphene provides a facile method to enhance the low-temperature activities of the Cu-Mn binary catalysts and cut down the use of valuable Cu, showing great application potential.

Alkaline etched hydrochar-based magnetic adsorbents produced from pharmaceutical industry waste for organic dye removal.

A large amount of pharmaceutical industry waste (PIW) was inevitably produced every year, and the PIW can be degraded by high temperature reaction to form porous structures. The study proposed an innovative pathway to valorize PIW with hydrothermal carbonization (HTC) coupled with alkali etching (AE). Without adding any additives, magnetic hydrochar could be generated with rough surface topography and suitable specific surface area (SBET) by this method. Effects of HTC conditions and alkaline solution concentrations on the physicochemical and adsorption properties of PIW were investigated, and adsorption mechanism was explored. Based on evaluations of the magnetism, cyclic regeneration, and heavy metal leaching properties of the products, the feasibility of preparing magnetic adsorbents with solid waste by HTC coupled AE was established. The alkaline etching pharmaceutical industry waste (AEPIW) hydrochar showed the highest SBET (54.64 m2/g) after the PIW was treated by 260 °C for 2 h plus 1 mol/L KOH. The removal rate of methylene blue (MB) could exceed 90% and the saturated magnetization was ~8 emu/g. The proposed new method was able to convert the low-value solid industrial waste into high-performance hydrochar-based magnetic adsorbents, which was tested to have a capability to efficiently and sustainably remove organic pollutants from water.

A sustainable revival process for defective LiFePO4 cathodes through the synergy of defect-targeted healing and in-situ construction of 3D-interconnected porous carbon networks.

The reutilization of spent cathode materials plays a key role in the sustainable development of Li-ion battery technology. However, current recycling approaches generally based on hydro-/pyrometallurgy fail to cater to Co-free cathodes (e.g., LiFePO4, or LFP) owing to high consumption and secondary contamination. Here, a sustainable process is proposed for the revival of defective LFP cathodes through the synergy of defect-targeted healing and surface modification. Li deficiency and Fe oxidation of cathodes are precisely repaired by solution-based relithiation; meanwhile, 3D-interconnected porous carbon networks (3dC) are in-situ constructed with the intervention of salt template during annealing, which enhances the rate performance and electronic/ionic conductivity, by providing more convenient migration channels for Li ions and controlling carbon hybridization. Nitrogen is also doped via induction of urea to fabricate advanced nanohybrid rLFP@3dC-N. New cells using rLFP@3dC-N as cathode exhibit a reversible capacity of up to 169.74 and 141.79 mAh g-1 at 0.1 and 1C, respectively, with an excellent retention rate of over 95.7% at 1C after 200 cycles. Impressively, a high capacity of 107.18 mAh g-1 is retained at 5C. This novel concepts for Li replenishment and the construction of ion-transfer channels as well as conductive networks facilitate the regeneration of spent LFP and the optimization of its high-rate performance.

Thermal co-treatment of aluminum dross and municipal solid waste incineration fly ash: Mineral transformation, crusting prevention, detoxification, and low-carbon cementitious material preparation.

Harmless disposal and resource utilization of hazardous industrial wastes has become an important issue with the green development of human society. However, resource utilization of hazardous solid wastes, such as the production of cementitious materials, is usually accompanied by a pretreatment process to remove adverse impurities that contaminate the final product. In this study, aluminum dross (AD) was thermally co-treated with another hazardous waste, municipal solid incineration fly ash (MSWI-FA), to synergistically solidify F and Na, control leaching of heavy metals, and remove chloride impurities. Significant crusting was observed when AD was thermally treated by itself, but not when AD and MSWI-FA were thermally co-treated. In the process of co-thermal treatment, the remaining Cl, Na, and K contents were reduced to as low as 0.3%, 1.8%, and 0.6%, respectively. CaO and SiO2 in MSWI-FA reacted with Na3AlF6 and Al2O3 in AD, and formed CaF2 and Na6(AlSiO4)6, which contributed to the prevention of crusting and limited the leaching concentrations of F and Na to below detection thresholds and 270.6 mg/L, respectively. In addition, heavy metals were well solidified, and dioxins were fully decomposed during thermal treatment. Finally, a sulfoaluminate cementitious material (SACM) with high early- and later-age strengths was successfully created via synergetic complementarity using thermally co-treated AD and MSWI-FA together with other solid wastes. Collectively, this study outlines a promising method for the efficient and sustainable utilization of AD and MSWI-FA.

A new co-processing mode of organic anaerobic fermentation liquid and municipal solid waste incineration fly ash.

A new co-processing mode of waste liquid from anaerobic fermentation of organic wastes and municipal solid waste incineration fly ash (MSWI-FA) dechlorination is reported in this paper. Taking acetic acid, the most common organic acid in anaerobic fermentation systems, as the representative of anaerobic fermentation organic acids, the improvement of the dechlorination effect and the mechanism of washing MSWI-FA with low concentrations of organic acid lotion were explored. The chlorine content of MSWI-FA was reduced to 0.82% after the optimal process washing pretreatment. Three anaerobic fermentation waste liquids (AFWLs) were used to verify that the chlorine content of MSWI-FA could be reduced to less than 1%, and the dechlorination effect of brewery wastewater, which reduced the chlorine content of MSWI-FA to 0.91%, was the best at this. The influence of the washing process on MSWI-FA pyrolysis was reflected in the whole process. The release of chloride decreased and the weight loss was mainly due to the release of CO2. The melting point of MSWI-FA, washed by the optimal process, was reduced by nearly 30 ℃, and only 0.06% chlorine remained after calcination at 1100 ℃, which was extremely beneficial in reducing the release of trace elements in MSWI-FA during heat treatment, and for the preparation of cement raw meal.

Study on the synergy effect of MnOx and support on catalytic ozonation of toluene.

MnOx has received widespread attention in low-temperature catalytic oxidation of VOCs, however, the synergy effect of MnOx and support on the VOCs catalytic ozonation were rarely studied. In this study, five different MnOx/X (X: MCM-41, 13X, ZSM-5, HY, USY) were synthesized and found their support greatly affect the catalytic oxidation activity. MnOx/MCM-41 presents the largest specific surface area, pore volume and unique surface morphology, and thereby provides more sites for MnOx loading and VOCs adsorption. Moreover, MnOx/MCM-41 presents a high proportion of Mn3+, which helps to enhance the ion exchange capability, and thus promotes the regeneration of oxygen vacancies. Furthermore, a part of Mn was proved to be introduced into the MCM-41 lattice, which can promote the electron transfer between the active components and the support, and thereby effectively improve the surface electronic properties of the catalyst. The toluene catalytic experiments showed that MnOx/MCM-41 exhibited the best catalytic activity, presenting complete degradation of O3 and VOCs at room temperature. In addition, 5 wt%MnOx/MCM-41 exhibited better catalytic activity than other loading, and its higher surface oxygen species endowed it with strong water resistance and stability. In-situ DRIFTs indicated that toluene was initially oxidized into benzyl alcohol during the adsorption process, and then decomposed to intermediate products (benzaldehyde, phenolate, etc.) during the catalytic ozonation process, and finally oxidized to carbon dioxide. In conclusion, the supply of loading sites and the improvement of interfacial electron transfer are the manifestations of the synergy between the support and MnOx, leading to the promotion of the catalytic ozonation of VOCs.

Discovering the key role of MnO2 and CeO2 particles in the Fe2O3 catalysts for enhancing the catalytic oxidation of VOC: Synergistic effect of the lattice oxygen species and surface-adsorbed oxygen.

Highly active mesoporous Fe-Mn-Ce catalysts with high specific surface area (SBET) were synthesized by a modified precipitation process for catalyzing toluene oxidation. The Fe0.85Mn0.1Ce0.05 catalyst presents richer surface oxygen species (OS), a higher proportion of Mn4+ and Ce4+, a higher concentration of lattice defects and oxygen vacancies, the highest Oads/Olatt ratio, and a superior low-temperature redox property compared with the Fe-Mn binary oxide and Fe2O3 and MnO2 catalysts. The properties contribute to a high catalytic activity to achieve T90% of toluene conversion at 264 °C and 185 °C with a gas hourly space velocity (GHSV) at 180,000 and 20,000 mL/(g∙h), respectively. The introduction of a slight quantity of Ce and Mn onto the Fe2O3 catalyst is the key to enhancing the synergistic effect of the lattice OS and surface-adsorbed oxygen, contributing to the activation oxidation procedure of toluene. In-situ DRIFTS analysis reveals that the rich oxygen vacancy concentration of catalysts accelerates the key steps for the generation and activation of oxidized products. These catalysts with rich oxygen vacancies can efficiently diminish the accumulation of a small number of the intermediary species (phenolate, C6H5-OH) produced during the catalytic oxidation of toluene.

Effect of additives on the distribution of three-phase products of oily sludge subjected to microwave pyrolysis.

This study aimed to explore the influence of activated carbon, oily sludge pyrolysis residue, and biochar and their contents on the distribution of three-phase products of oily sludge subjected to microwave pyrolysis. A microwave reaction system, refinery gas analyzer, and chromatography-mass spectrometry were used to carry out the experiment and analyze the results. The results showed that all three additives reduced the yield of solid products and increased the yield of gas products. With an increase in the additive content, the volatile matter and moisture content in the pyrolysis residue greatly reduced. The content of CH4 and H2 in the pyrolysis gas increased with an increase in the additive content. When the amount of activated carbon was 20%, the H2 content reached a maximum (39.7%), and when the amount of biochar was 20%, the CH4 content reached a maximum (44.5%). All three additives increased the content of small molecules in the pyrolysis oil; when 10% activated carbon was added, the oil recovery rate reached up to 78.5%. The results of this study can guide the industrial application of microwave pyrolysis oily sludge.

Encapsulation of cesium with a solid waste-derived sulfoaluminate matrix: A circular economy approach of treating nuclear wastes with solid wastes.

It is of great importance to safely dispose nuclear wastes with the development of nuclear industries. Past approaches to this problem have included immobilizing radioactive cesium in Portland cement-based matrices; however, the leaching rates of cesium are relatively high, especially as the leaching temperature increases. This paper explores a high-efficiency and cost-effective approach for encapsulating cesium using a sulfoaluminate cement (SAC) matrix, which was prepared via synergetic use of industrial solid wastes. Leaching results showed that, the apparent diffusion coefficient values of cesium were only ~1.4 × 10-15 cm2/s and ~5 × 10-18 cm2/s at 25 â„ƒ and 90 â„ƒ leaching conditions, respectively. These values were several orders of magnitude lower when compared with previously reported values, indicating the excellent encapsulation performance of the solid-waste-based SAC for cesium. Moreover, the heavy metals contained in the industrial solid waste were also effectively immobilized. A mechanistic analysis revealed that cesium was encapsulated in the SAC matrices stably by a physical effect. Finally, a life cycle assessment and economic analysis indicated that this approach was environmental-friendly, cost-effective, and energy-saving. This work provides a promising strategy for effective encapsulation of cesium and synergetic treatment of industrial solid wastes.

Investigation on removal effects and condensation characteristics of condensable particulate matter: Field test and experimental study.

Condensable particulate matter (CPM) has become the main part of the total primary PM emitted from stationary sources and has aroused increasing concern. In this work, the removal effects of wet flue gas desulfurization (WFGD) on CPM components were studied. A new CPM-containing flue gas system was designed and used to investigate the condensation characteristics of 16 PAHs, sulfuric acid mist and SO2 conversion into CPM. Some interesting results were obtained and include the following: (i) The removal efficiencies of WFGD on both CPM inorganic and organic fraction reached 81.0% and 67.3%, respectively. (ii) The removal efficiency data obtained for C21-C29 and 5-ring PAHs revealed that organic components with high boiling points and low volatility in CPM are easily removed by WFGD. Condensation experimental results indicated that the condensation ratios of PAHs generally increased with the number of fused benzene rings, while the increase of flue gas moisture content might inhibit the conversion of PAHs into CPM. (iii) The concentrations of SO42-, Ca, and Na accounted for 48.7% of CPM inorganic fraction after desulfurization, while Ca was barely removed by WFGD. Condensation experiments indicated that most SO42- in CPM arose from sulfuric acid mist, rather than from sulfate aerosols. Note that only <20% of the sulfuric acid mist belonged to the CPM category, which might help to develop specialized deep purification strategy for SO3. In addition, SO2 could cause a high positive bias for the CPM field test although its condensation ratio was only 2.7%. This work provides a basic reference for subsequent CPM formation and reduction researches.

Desorption of CO2, SO2, and NH3 in the vacuum evaporation of desulfurization wastewater.

Mechanical vapor compression and multi-effect evaporation have been widely used in achieving zero discharge of desulfurization wastewater as they are energy-saving and efficient technologies. Solubilized weak ions, such as CO32-, SO32-, and NH4+, in the desulfurization wastewater are partly converted into CO2, SO2, and NH3, respectively, during the vacuum evaporation process, thus affecting the heat exchange and compressor performance. In this study, the migration and coupling mechanism of CO2, SO2, and NH3 desorption in desulfurized wastewater under vacuum evaporation were analyzed. The effects of temperature, pressure, reaction time, and other factors on the migration process were discussed. The hydrolysis and electrolytic equilibrium constants of the related ions were obtained for temperatures between 70 and 90 °C. The results demonstrate the relationship between the desorption capacities of CO2, SO2, and NH3 and the hydrolysis constants of their respective ions. The desorption of CO2 and NH3 increased significantly when CO32- and NH4+ coexisted, whereas the SO2 desorption capacity remained low under the same experimental conditions. The experimental results indicate that the desorption of CO2, SO2, and NH3 is controlled by chemical reactions and can be described by first-order reaction kinetics.

Pretreatment of municipal solid waste incineration fly ash and preparation of solid waste source sulphoaluminate cementitious material.

Municipal solid waste incineration fly ash (MSWI-FA) is a kind of hazardous waste, and it is of great significance to treat it harmlessly and resourcefully. This study proposes the preparation of sulphoaluminate cementitious materials using water-washed MSWI-FA, flue-gas desulfurization gypsum, and aluminum ash. The changes in the composition and morphology of MSWI-FA before and after washing were investigated, and the effects of various washing conditions on the removal rate of chloride salt from MSWI-FA were analyzed. The effect of firing temperature on the mineral content of the sulphoaluminate cementitious material was also investigated. In addition, the strength and heavy metal leaching characteristics of the corresponding materials were tested. The results show that more than 90% of chloride salts were removed by water washing MSWI-FA two times. Using MSWI-FA as the main raw material, the sulphoaluminate cementitious material containing mostly calcium sulphoaluminate and dicalcium silicate could be prepared successfully at 1270 °C; the amount of MSWI-FA in the raw material can be as high as 35% (dry weight). Moreover, the sulphoaluminate cementitious material can effectively solidify heavy metals in the raw materials. The leaching concentrations of eight heavy metal ions, i.e., Cu, Zn, Cd, Pb, Cr, Ni, Ba, and As are far lower than the concentration limits set by national standards.

Current status of applying microwave-associated catalysis for the degradation of organics in aqueous phase - A review.

Interactions between microwaves and certain catalysts can lead to efficient, energy-directed convergence of a relatively dispersed microwave field onto the reactive sites of the catalyst, which produces thermal or discharge effects around the catalyst. These interactions form "high-energy sites" (HeS) that promote energy efficient utilization and enhanced in situ degradation of organic pollutants. This article focuses on the processes occurring between microwaves and absorbing catalysts, and presents a critical review of microwave-absorbing mechanisms. This article also discusses aqueous phase applications of relevant catalysts (iron-based, carbon-based, soft magnetic, rare earth, and other types) and microwaves, special effects caused by the dimensions and structures of catalytic materials, and the optimization and design of relevant reactors for microwave-assisted catalysis of wastewater. The results of this study demonstrate that microwave-assisted catalysis can effectively enhance the degradation rate of organic compounds in an aqueous phase and has potential applications to a variety of engineering fields such as microwave-assisted pyrolysis, pollutant removal, material synthesis, and water treatment.

Exothermic laws applicable to the degradation of o-phenylenediamine in wastewater via a Fe3+/H2O2 homogeneous quasi-Fenton system.

We studied the exothermic laws of Fe3+/H2O2 homogeneous quasi-Fenton degradation of o-phenylenediamine in waste water, and analyzed the effects of [H2O2] and [Fe3+], initial reaction temperature, and other factors on the solution temperature elevation (Δt), temperature elevation duration (T), and chemical oxygen demand degradation rate (η) during the degradation of the target pollutant. Our study found that [H2O2] is a major factor affecting Δt, while [Fe3+] and t 0 are the main factors influencing the exothermic reaction rate. For the conditions wherein [H2O2] is 0.2 mol L-1, [Fe3+] is 10 mmol L-1, pH = 7.8, initial reaction temperature is 30 °C, and reaction duration is 30 min, Δt of 200 mL of 0.04 mol L-1 o-phenylenediamine is 7.2 °C and η is 93.45%. The exothermic reaction between the free radicals (·OH and ) and o-phenylenediamine and the exothermic reaction due to auto-consumption of free radicals are the main reasons for the increased temperature of the solution.

Rapid degradation of malachite green by CoFe2O4-SiC foam under microwave radiation.

This study demonstrated rapid degradation of malachite green (MG) by a microwave (MW)-induced enhanced catalytic process with CoFe2O4-SiC foam. The catalyst was synthesized from CoFe2O4 particles and SiC foam by the hydrothermal method. X-ray diffraction and scanning electron microscopy techniques were used to confirm that CoFe2O4 particles were settled on the surface of SiC foam. In this experiment, a novel fixed-bed reactor was set up with this catalyst for a continuous flow process in a MW oven. The different parameters that affect the MW-induced degradation rate of MG were explored. The MW irradiation leads to the effective catalytic degradation of MG, achieving 95.01% degradation within 5 min at pH 8.5. At the same time, the good stability and applicability of CoFe2O4-SiC foam for the degradation process were also discussed, as well as the underlying mechanism. In brief, these findings make the CoFe2O4-SiC foam an excellent catalyst that could be used in practical rapid degradation of MG.

Experimental study of destruction of acetone in exhaust gas using microwave-induced metal discharge.

Volatile organic compounds (VOCs) are air pollutants that pose a major concern, and novel treatment technologies must be continuously explored and developed. In this study, microwave-induced metal discharge was applied to investigate the destruction of acetone as a representative model VOC compound. Results revealed that metal discharge intensity largely depended on microwave output power and the number of metal strips. Microwave metal discharge exerted the distinct combined effects of intense heat, strong light, and plasma. In the case of MW without metal discharge, the decrease in acetone at 200 ppm was remarkably limited (approximately 5.5% (mol/mol)). By contrast, in the case of microwave-induced metal discharge, a considerably high destruction efficiency of up to 65% (mol/mol) was obtained at low concentrations. This finding highlights the potential of microwave-induced discharge for VOC removal. Initial assessment indicated that energy consumption can be acceptable.