Waste Gas Research Articles

Synergistic removal of NO and CO in industrial waste gas by Fe-modified Cu/TiO2 catalysts: The synergistic effect of metal oxides interaction

NH3-based selective catalytic reduction (NH3-SCR) combined with carbon monoxide (CO) catalytic oxidation is a productive way to synergistically remove nitrogen oxides (NOx) and CO from industrial waste gas. Catalyst is the undoubtedly centerpiece of the synergistic removal technology, which has aroused tremendous attention. Herein, in this investigation a variety of Cu/TiO2 catalysts modified by various metal oxides were prepared by impregnation method, and the excellent synergistic removal performance of Fe-modified Cu/TiO2 catalyst was observed. The Cu/TiO2 catalyst with a 7 wt% Fe doping amount exhibited the highest NO and CO removal efficiency (86 % for NO at 300 °C and over 98 % for CO from 300 ∼ 400 °C). Through a series of characterization techniques, it was discovered that Cu and Fe oxides interacted to evenly distribute them throughout the surface of TiO2 support, resulting in smaller particle size and abundant variable valence species (Cu+/Cu2+ and Fe2+/Fe3+) to enhance the redox performance of the catalysts. Moreover, the creation of additional surface chemisorbed oxygen, the adsorption of NO and CO, and the improvement of surface acidity were all facilitated by the electron transfer between various Cu and Fe species. In addition, in-situ diffuse reflectance infrared transform spectroscopy (in situ DRIFTS) results revealed the interaction between NH3-SCR and CO oxidation. This study proposes a viable approach to develop efficient catalysts for the synergistic removal of NO and CO in industrial applications.

Enhancing the performance of biofilters with sorption ability for simultaneous purification of landfill gases using laterite soil-based substrate

Various harmful gas emissions are a major controversial issue globally, and open dumpsites have become a leading contributor to atmospheric pollution. The study aims to introduce a high-performance landfill gas purification substrate using laterite soil, an iron, and aluminum-rich, highly available soil type in tropical countries; the final suggested substrate contained uniformly mixed laterite soil and compost with a 4:1 fraction by volume. A self-design setup that can maintain moisture content and aerobic conditions was used with an active landfill gas collection system through the gas wells established on the Karadiyana landfill in Sri Lanka under a tropical climate. The elimination capacity of CH4, NH3, VOCs, and H2S were 202860 ± 51595, 91 ± 30, 75 ± 27, and 6 ± 3 mg m−3 h−1 with 91 ± 3, 96 ± 1, 93 ± 3 and 83 ± 4% of removal efficiencies respectively at a 9.4 min empty bed residence time (EBRT). Selected laterite soil acts as an adsorption material and provides a better bio-filtering substrate with compost due to its specific characteristics. The hybrid gas purification process, absorption, and biofiltration within the proposed material were the reasons for higher performance, and the setup may be successful under the industrial waste gas streams. Further investigation should be carried out to study the medium's effectiveness as the covering layer on the dump with the successful lowest thickness, regarding secondary pollutants, and industrial applicability under unique specific conditions.

Development of a Real-Time NOx Prediction Soft Sensor Algorithm for Power Plants Based on a Hybrid Boost Integration Model

Nitrogen oxides (NOxs) are some of the most important hazardous air pollutants from industry. In China, the annual NOx emission in the waste gas of industrial sources is about 8.957 million tons, while power plants remain the largest anthropogenic source of NOx emissions, and the precise control of NOx in power plants is crucial. However, due to inherent issues with measurement and pipelines in coal-fired power plants, there is typically a delay of about three minutes in NOx measurements, bringing mismatch between its control and measurement. Measuring delays in NOx from power plants can lead to excessive ammonia injection or failure to meet environmental standards for NOx emissions. To address the issue of NOx measurement delays, this study introduced a hybrid boosting model suitable for on-site implementation. The model could serve as a feedforward signal in SCR control, compensating for NOx measurement delays and enabling precise ammonia injection for accurate denitrification in power plants. The model combines generation mechanism and data-driven approaches, enhancing its prediction accuracy through the categorization of time-series data into linear, nonlinear, and exogenous regression components. In this study, a time-based method was proposed for analyzing the correlations between variables in denitration systems and NOx concentrations. This study also introduced a new evaluation indicator, part of R2 (PR2), which focused on the prediction effect at turning points. Finally, the proposed model was applied to actual data from a 330 MW power plant, showing excellent predictive accuracy, particularly for one-minute forecasts. For 3 min prediction, compared to predictions made by ARIMA, the R-squared (R2) and PR2 were increased by 3.6% and 30.6%, respectively, and the mean absolute error (MAE) and mean absolute percentage error (MAPE) were decreased by 9.4% and 9.1%, respectively. These results confirmed the accuracy and applicability of the integrated model for on-site implementation as a 3 min advanced prediction soft sensor in power plants.

Capacities of sorbents prepared by impregnation of inorganic carriers with PEI using different methods

The study presented here focused on the research of adsorbents for the separation of carbon dioxide from flue gas or other waste gases. Specifically, it focused on the possibility of eliminating the permanent problem with the insufficient resistance of inorganic adsorbents to unwanted – parasitic – adsorption of moisture from the processed gas. Based on the promising data published in recent papers regarding the wet impregnation of adsorbents with branched polyethyleneimine (PEI), four methods for the preparation of PEI-impregnated zeolite were tested. Penetration of the agent into the porous structure of the zeolite was achieved by: applying ultrasound, applying vacuum, combining vacuum and overpressure and boiling off the solvent without further operation. The raw zeolite was characterized by X-ray fluorescence spectrometry and X-ray diffractometry and also subjected to textural analysis. The characterization of the impregnated products mainly included thermogravimetric analysis, textural analysis and organic elemental analysis. In addition to gravimetric screening, the adsorption capacities of raw zeolite and impregnated products were primarily determined using a pressure flow-through apparatus with a fixed bed adsorber. The experimental conditions were determined to be close to real industrial installations: temperature during adsorption 20 and 40 °C, pressure during adsorption 600 kPa and 15% volume fraction of CO2 in the gas. Desorption was carried out by a combination of thermal desorption at 80 °C and vacuum. By reproducing the impregnation procedures from the literature, a PEI loading in the range of 4.1–23.7% was achieved, which is significantly lower than the literature sources state for the same preparation procedures. The measurement of textural properties verified that, depending on the value of PEI loading, there is a gradual reduction of the specific surface area, the total pore volume and the virtual disappearance of micropores and small mesopores. Specifically, at a PEI loading of 4%, the BET surface area decreased compared to the pristine zeolite from 29.4 to 2.9 m2 g–1 and at the same time the total pore volume decreased from 0.13 to 0.02 cm3 g–1, etc. The measurement of capacities did not confirm almost any of the results published in the literature. Without exception, the adsorption capacity decreased with the amount of PEI introduced into the zeolite particles. E.g. if a gas with 80% relative humidity and a content of 15% CO2 was used at a pressure of 600 kPa and a temperature of 40 °C, the capacity (by mass) decreased due to impregnation from 2.4% (for raw zeolite) to 0.8% for the sample with PEI mass fraction of 19%. Tests using dry gas resulted in even more marked deterioration. Thus, one can only partially agree with the literature data in the sense that humidity slightly compensates the negative effect of PEI on capacity. The effect, where the capacity increases with increasing temperature due to the replacement of physical CO2 adsorption by its chemisorption in the PEI layer, was also not confirmed. For example, for the above sample, humidity and pressure, the capacity was 0.9% at 20 °C. The impregnation procedure based on boiling off the solvent turned out to be completely unusable and, despite repeated rigorous attempts to reproduce it, did not lead to a product with a measurable capacity. The results of the study can be summarized in the following sentence. The problem is not that the experiments did not lead to a positive result, but above all the fundamental discrepancy between the published data and the attempts to reproduce them.

OI url: https://doi.org/10.30574/wjarr.2024.23.3.2934

Artificial intelligence (AI) has emerged as a key enabler in optimizing renewable energy systems, significantly contributing to global efforts toward environmental sustainability. This review explores the application of AI technologies in enhancing the efficiency, reliability, and integration of renewable energy sources such as solar, wind, and hydropower. It focuses on how machine learning (ML), deep learning (DL), and other AI-driven algorithms improve energy forecasting, grid management, and storage optimization. Survey data and case studies demonstrate the potential of AI to minimize energy waste, reduce costs, and lower greenhouse gas emissions, reinforcing its role in transitioning to a sustainable energy future. The review concludes with a discussion of challenges and future research directions.

Does the environmental impact of banks affect their financial performance?

AbstractWe empirically study the environmental impact of banks, i.e., the negative externality on the environment and society deriving from the use of a natural resource or the emission of a pollutant. We find that environmental “impact ratios”, that is, environmental damage costs in proportion to total revenues are negatively correlated with bank profitability. Furthermore, banks with a stronger impact on the environment are valued less by equity market investors and pay less cash to shareholders. Among environmental categories, potential damage from greenhouse gas emissions or waste seems to be especially severe. We provide important insights for banks’ environmental management. If bankers can address businesses and practices to be more renewable and lower in their emissions, they could improve both the operating and the market performance. Thus, firms would be financially more stable and could react smoothly to the recent introduction of stricter and onerous environmental regulations.

Upcycling acid waste gas containing H2S and CO2 into syngas and sulfur by non-thermal plasma coupled with Zn-Mo/Al2O3 catalyst

Synergistic conversion of H2S and CO2 into syngas and sulfur in one step, not only achieves harmless treatment, but also produces valuable chemicals, which is an ideal strategy for waste gas upcycling. Nevertheless, due to the kinetic inertia and high thermodynamic stability of H2S and CO2, the process of the reaction has not received enough attention. Non-thermal plasma has advantages over thermal processes in the process of enhanced conversion owning to its non-equilibrium properties. Herein, a novel method of non-thermal plasma coupled by Zn-Mo/Al2O3 catalyst was demonstrated for the simultaneous conversion of H2S and CO2. Furthermore, compared to the single component catalysts (ZnS/Al2O3 and MoS2/Al2O3), the Zn-Mo/Al2O3 catalysts with different Zn/Mo ratios had excellent catalytic performance. In particular, the ZM(4/4) catalyst showed complete conversion of H2S and approximately 62 % of CO2 conversion, with the highest energy efficiency of 0.95 mmol/kJ and 120 h long-term stability. Meanwhile, the mechanism of the synergistic reaction between non-thermal plasma and catalysis was revealed by means of in-situ optical emission spectrometry. This study offers a new strategy for catalyst design for the highly efficient conversion of H2S-CO2 acid waste gas via plasma-catalytic method, and highlights the synergy between Zn-Mo/Al2O3 catalyst and non-thermal plasma to promote catalytic performance.

Performance analysis of refuse‐derived fuel gasification plant with carbon capture and storage for power, heating, and hydrogen production

AbstractAmong various waste‐to‐energy technologies, gasification is one of the most promising, because of high efficiency, feedstock flexibility, and carbon capture potential. This case study is focused on comprehensive analysis of integrated gasification combined cycle‐based plant with refuse‐derived fuel (RDF) as feedstock and carbon capture. As there are hardly any studies focused on simulation of waste gasification with carbon capture, most of which are lacking important process specifics, this study addresses existing research gap. Process flowsheets are developed in detail according to literature data for various process configurations and simulated in AspenPlus software, while obtained results on material and energy balance were used for estimation of plant efficiency and performance indicators. Waste generation data in Novi Sad, Serbia, were used for determination of RDF flowrate. Configurations include different syngas cleaning pathways, final products (power, heating, and hydrogen) and co‐gasification with coal. Cogeneration increases overall plant efficiency from 27%–36% (power production only) to 63%–76%. High net hydrogen efficiencies, around 58%, compensate lower power and thermal energy production in hydrogen‐based configurations. Overall, co‐gasification produces better results due to higher feedstock heating value. Obtained results will be used in further research for environmental and economic evaluation to provide multi‐level assessment of proposed processes.

Potentials of synthetic biodegradable mulch for improved livelihoods on smallholder farmers: a systematic review

Plastic waste in agriculture, particularly from polyethylene mulch, poses significant environmental challenges. Synthetic biodegradable mulch has emerged as a sustainable alternative, derived from renewable resources such as thermoplastic starch, polylactic acid, polyhydroxyalkanoates, and copolyesters. This review explores the benefits of synthetic biodegradable mulch, its environmental impact, and the policy landscape to support its adoption. A review of existing literature was conducted, focusing on three aspects: (1) the performance of synthetic biodegradable mulch in crop production and pest control, (2) the environmental, socioeconomic, and climate resilience compared to polyethylene mulch, and (3) the institutional policies that promote synthetic biodegradable mulch adoption. The analysis considered comparative data on yield, pest management, and sustainability metrics. Synthetic biodegradable mulch performs similarly or better than polyethylene mulch in various agricultural practices. It enhances crop yield, quality, and weed suppression, acts as a physical barrier against pests and diseases, reduces chemical usage, and aids in water and nutrient management. Moreover, synthetic biodegradable mulch offers environmental benefits by reducing plastic waste, microplastic pollution, and greenhouse gas emissions, contributing to climate change mitigation. While synthetic biodegradable mulch provides numerous advantages, adoption faces challenges such as high initial costs, farmer preferences, and the regulatory framework. Effective institutional policies and increased consumer demand could drive wider adoption, offering potential for improved livelihoods among small farmers while promoting environmental sustainability.

Design of Oil Mist and Volatile-Organic-Compound Treatment Equipment in the Manufacturing Plant

To effectively confront the acute challenge of global warming, at the present stage, the Chinese government has designated carbon reduction as the core objective to accomplish the coordinated control of greenhouse gas and pollutant emissions. As China is a major manufacturing country, with the continuous improvement of air emission standards, it is particularly necessary to carry out the design of more efficient volatile organic pollutant emission devices. This study takes a treatment system with a waste gas ventilation volume of 6 × 104 m3·h−1 as an example, adopts the end treatment approach of adsorption and catalytic combustion coupling, and designs a purification device composed of multistage oil-mist recovery, electrostatic adsorption, dry filtration, activated-carbon adsorption and desorption, catalytic combustion, etc. It also employs the fuzzy proportional-integral-derivative fine temperature control algorithm, and the temperature overshoot was decreased by 85%. The average emission concentration of volatile organic compounds at the equipment outlet is 6.56 mg·m−3, and the average removal rate is 93.99%, far surpassing the national emission standards. The device operates efficiently and stably, confirming that the end-coupled treatment system based on the adaptive fuzzy proportional-integral-derivative temperature control strategy can effectively handle volatile organic compounds with oil mist and holds significant promotion and research value.

CFD-based investigation of NO x removal from industrial waste gas by selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) process using NH3

CFD-based investigation of NO_<i>x</i> removal from industrial waste gas by selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) process using NH₃

Experimental study on the macroscopic and microscopic properties of cement paste backfill after treatment with carbon dioxide carbonize filling slurries during the mixing process

Introducing CO2 during the mixing process of filling slurry for wet carbonation enables simultaneous carbonation and hydration reactions of the carbonated filling slurry (CSL). This study evaluates the microstructural evolution and strength development of carbonated cemented paste backfill (CCPB) under different carbonation times, and discusses the carbonation products and carbon sequestration of CCPB. The results reveal that introducing 99% pure CO2 at a flow rate of 1 L/min for 10 min into the filling slurry in a non-sealed container effectively optimizes the microscopic pore structure and mechanical properties of CCPB, achieving a carbon sequestration rate of 6.42%. Short-term carbonation leads to a continuous decrease in the T2 relaxation signal of CSL in the early hydration stage, enhancing pore structure by converting secondary pores to micropores. The main carbonation product is calcite crystalline CaCO3, which forms a dense carbonation layer on the surface of the tailings particles. However, prolonged carbonation results in the formation of microscopic pore encapsulation layer, hindering further CO2 diffusion, reducing carbonation efficiency, and deteriorating the mechanical properties of CCPB. With a carbonation time of 10 min, the UCS and EM of CCPB with different cement-to-tailings ratios show significant improvement, and the specimens exhibit lower fragmentation and fewer secondary cracks, maintaining better integrity after failure. In conclusion, the wet carbonation of filling slurry not only enhances the strength of the filling material but also achieves the reutilization of gaseous and solid wastes through carbon sequestration filling method, providing an efficient and eco-friendly solution for mine backfilling.

Identification of atmospheric emerging contaminants from industrial emissions: A case study of halogenated hydrocarbons emitted by the pharmaceutical industry

With the development of the pharmaceutical industry, halogenated hydrocarbons, which are the main raw materials and emissions of the pharmaceutical industry, may be defined as atmospheric emerging contaminants due to toxicity and low oxidation of the atmosphere. This study analyzed the volatile organic compounds (VOCs) emissions from four pharmaceutical companies located in the Yangtze River Delta. Samples were taken three times at each of the selected fixed and fugitive sampling sites in each company. Through testing, 141 VOCs were identified. The mean concentration and proportion of halogenated hydrocarbons from the four pharmaceutical companies were the highest of all the industries in the industrial park. They reached 18.9 ppm and 28.8 %, respectively. Fixed emissions of the companies exhibited the mean maximum concentration of dichloromethane and chlorobenzene, which are 11.4 ppm and 250.67 ppb. The mean concentration of fugitive emission of dichloromethane from the four companies in this study is lower than that of pharmaceutical companies in other studies. Newly detected halogenated hydrocarbons, such as 1,1-dichloropropanone and dichloronitromethane, present potential non-cancer and cancer risks to workers. Chlorobenzene was identified as a key potential cancer risk halogenated hydrocarbon the value of which reaches 0.00965. 2,6-dichloropyridine could be a potential emerging contaminant due to its lower MIR value and higher potential cancer risk. The study suggests that relevant pharmaceutical companies focus on the emissions of chlorobenzene and dichloromethane, which may be the atmospheric emerging contaminants for the pharmaceutical industry and focus on improve the treatment of waste gases in workshops and sewage stations.

Whisky decarbonisation potential using bio-waste

The objective was to investigate the potential of the Scottish Whisky industry to employ the circular economy to decarbonise and reduce costs, using its own bio-waste as a source of energy to power distilleries. The analysis uses a literature review of the fossil fuel energy for heat used in modern distilleries in terms of MJ/Lalcohol. It then determines the energy content of the whisky distillery bio-wastes: draff, pot ale, spent lees and wash (SLW). Outside the distillery there are bio-wastes in the barley straw on farms and from the malt-house, barley husks, rootlets and dark grains and the maturation barrel preparation area with a wood char waste. The energy in the wastes is also expressed as MJ/Lalcohol which then enables the determination of the proportion of the energy to operate the distillery that can be provided from the bio-waste. The distillery wastes all have a high water content, the amount of which is reviewed. The energy to evaporate this water is determined to give the net energy from the bio-wastes. The findings are that in the distillery, including the energy to evaporate water, requires 60 MJ/Lalcohol, with half of this used to evaporate water. Most of the energy in wet wastes is used to evaporate the water and there is only 8.7 MJ/Lalcohol to contribute to the distillery energy requirements. For dry draff and PAS the energy is sufficient to operate the distillery, but the energy to dry the draff has to be provided at some stage in the process. However, there is enough energy in barley straw and malthouse wastes to provide the rest of the heat required in a distillery and to completely decarbonise the whisky industry. This is the first time that all the bio-wastes have been assessed in whisky manufacture, from the farm to the maturation barrel stores. It is proposed that the best way to use these diverse bio-wastes is gasification of the solid wet waste to produce a biomass gasification gas (BGG) with direct burning of the BGG to generate the heat to burn the PA and SLW and evaporate the water.

Novel assessment of molten salt oxidation for cation exchange resin treatment: Effective neutralization of sulfurous gas with Li2CO3-Na2CO3-K2CO3 system

The conventional thermal treatment of cation exchange resin substantially releases sulfurous gases, causing significant equipment corrosion and air pollution. In contrast, the Li2CO3-Na2CO3-K2CO3 as an alkaline molten system effectively neutralizes sulfur gas and mitigates waste gas production inherent in thermal oxidation methods. In the molten salt oxidation process, the volume concentration of SO2 was reduced by 81.7 % compared to that in the traditional thermal oxidation process, and this method reduces the generation of hazardous gases such as CO, CH4, and C2H6. The integration of online gas mass spectrometry and phase stability diagrams for carbonate and sulfur interception products demonstrate excellent thermodynamic stability during the molten salt oxidation (MSO) process. Moreover, a more accurate assessment of the acid gas neutralization capacity of the molten salt system is provided, and the acid gas neutralization capacity of the Li2CO3-Na2CO3-K2CO3 carbonate system can reach 82.58 % at 800 °C. The predominant contributors to acid gas neutralization are Na2CO3 and K2CO3, as evidenced by waste salt composition and ternary phase diagrams. The stable presence of Li2CO3 throughout the MSO process contributes to the lowering of the melting point of the carbonate system to 393 °C.

Clean and sustainable recovery of valuable materials from InP scrap via controlled-pressure pyrolysis–spray condensation

Indium phosphide (InP) semiconductors play an irreplaceable role in optical communication, and with the expansion of the market scale, the amount of InP scrap, which has become an important secondary resource for recovering phosphorus and indium, has considerably increased. However, as a typical phosphorus containing material, InP scrap recycling is difficult and dangerous because phosphorus is flammable and releasing toxic and irritating smoke during combustion. In this study, a safe, clean, and sustainable “controlled-pressure pyrolysis–spray condensation” process is proposed. Firstly, InP is decomposed into phosphorus and indium under high-temperature conditions; phosphorus then evaporates into the vapor phase and is sprayed with warm water for condensation in water, whereas indium is enriched in the liquid phase. The feasibility of this process is proven by performing thermodynamic calculations and scaled-up experiments (hundred grams to kilograms) by using a self-designed equipment. At a decomposition temperature of 1323 K, micro-negative pressure, and holding time of 5 h, an indium ingot with a purity of 99.59 wt.% was obtained and the direct yield reached 98.2%. Industrial α-yellow phosphorus with a purity of >98 wt.% was obtained and safely stored in water, and the comprehensive recovery rate is >90%. The overall process produces zero waste gas, liquid, or residue. The new process is easy to implement in industrial applications when the equipment is fitted with a continuous feeding and discharging system. A convenient and safe method for the X-ray diffraction detection of yellow phosphorus is also developed in this study.

Prioritizing industrial wastes and technologies for bioenergy production: Case study

Energy supply stability in the industrial sector is crucial to maintain operational efficiency and avoiding costly disruptions. In the face of pressing environmental challenges, transitioning to sustainable, efficient, and eco-friendly energy sources is imperative. This study aims to assess the potential of industrial waste for bioenergy production in Khorasan Province, Iran, addressing the research gap of developing a comprehensive framework of criteria that was lacking in previous studies. Employing a combined technology and material assessment methodology, the research began with the collection and analysis of questionnaires to identify and weight critical criteria using Shannon Entropy and expert insights. The Additive Ratio Assessment method was then used to rank various types of industrial waste and technologies according to established value criteria. The Findings reveal that anaerobic digestion of organic waste emerges as the most viable bioenergy solution with an 85 % desirability score, followed by anaerobic digestion of sewage sludge and gasification of plastic waste, scoring 77.31 % and 69.41 %, respectively. The innovative aspect of this study is the development and implementation of five novel evaluation criteria, including process temperature, technology lifetime, production cost, waste collection cost, and waste separation cost, which have not been previously applied to the assessment of industrial waste for renewable energy production, especially in developing countries.

Waste not want not: the story of surgical trash.

Our escalating reliance on disposable products in the operating room has generated a large amount of waste, cost, and environmental pollution. Heath damages from the pollution caused by the US healthcare industry cause as much harm, as measured by disability-adjusted life years, as total medical errors. Our response to our own environmental impact should be proportional to that harm. Understanding the waste streams we create and the factors that contribute to our large waste generation in the operating room can help us target solutions to our most harmful practices. Recent studies within the field of medical waste in ObGyn have included a systematic review analyzing most effective practices for waste reduction and environmental life cycle analyses of specific medical procedures. Operating room waste includes regulated medical waste, pathologic waste/chemotherapy, sharps, general municipal waste, recycling, linens, and anesthetic gases. The most effective way to reduce the environmental impact from medical waste is to reduce our use of disposable supplies in favor of durable reusable materials. Other important interventions include eliminating 'overage' of unused supplies, optimizing use of anesthetic gas, custom pack scale backs, and proper waste segregation. This review of operative waste is intended to aid healthcare facilities in understanding and addressing their own environmental impact.

Highly effective direct conversion of H2S into COx-free H2 and S at low temperature over novel MoxC@ZrO2 microwave catalysts

Direct decomposition of H2S into H2 and S is an attractive alternative to the Claus process, because COx-free H2 and S can be simultaneously recovered from an abundant and toxic waste gas, which has huge social economic and ecological environmental benefits. However, it is still a great challenge to achieve the direct H2S decomposition reaction with high efficiency due to the thermal equilibrium limitation. Herein, a core-shell structured MoxC@ZrO2 was developed as novel microwave catalyst for microwave catalytic H2S decomposition. More specifically, the H2S conversion over MoxC@ZrO2 catalyst is as high as 99.9% at 650 °C, which immensely surpasses the H2S equilibrium conversion (6.1% at 650 °C). This study provides an effective strategy for the design of highly active microwave catalysts, and supplies a strategy for efficiently catalytic decomposition of H2S waste and recovering high-value hydrogen and sulfur at lower reaction temperatures.

Nexus between Returns on Equity and Disclosures of Greenhouse Gas Emissions, Waste Management, and Renewable Energy

Environmental sustainability is now being continuously researched in almost all areas of humankind. This study investigated the impact of environmental sustainability disclosures (proxy by renewable energy disclosures, Greenhouse Gas Emissions disclosures, and waste management disclosures) on the returns on equity of sampled Quoted Nigerian Financial Institutions. Purposely, Fourteen Quoted Nigerian Financial Institutions on the Nigerian Exchange Group were taken as the sample size for this study. The study spanned a period of 9 years from 2013 to 2021. The analysis was carried out using panel data and employing multiple regression models to assess the relationships between the variables using secondary data collated from the annual reports of Quoted Nigerian Financial Institutions. The findings of the study reveal that the impact of renewable energy disclosures (with coefficient estimate = -0.19295, t-value = -1.41 and p-value = 0.16), Greenhouse Gas Emissions disclosures (with coefficient estimate = -0.16105 &amp; the t-value = -1.18 p-value = 0.239, and waste management disclosures (with coefficient estimate = 0.124013, the t-value of 1 and p-value = 0.317) on returns on equity is not significant. This study concluded that the relationship between return on equity and environmental sustainability variables disclosures (proxy by Renewable Energy Disclosure and Greenhouse Gas Emissions) is unrelated.