Pub Date : 2024-09-16DOI: 10.1016/j.psep.2024.09.063
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.
{"title":"Highly efficient degradation of ethanol, acetaldehyde, and ethyl acetate removal by bio-trickling filter reactors with various fillers","authors":"","doi":"10.1016/j.psep.2024.09.063","DOIUrl":"10.1016/j.psep.2024.09.063","url":null,"abstract":"<div><p>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/m<sup>3</sup>·h, 9.55–15.06 g/m<sup>3</sup>·h, and 6.18–10.45 g/m<sup>3</sup>·h. Kinetic analysis showed the Michaelis-Menten model fit well, indicating enhanced removal potential. High-throughput of 16S rDNA sequencing identified dominant microorganisms like <em>Enterobacteriaceae</em> (13.89 %), <em>Stenotrophomonas</em> (29.23 %), and <em>Acinetobacter</em> (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.</p></div>","PeriodicalId":20743,"journal":{"name":"Process Safety and Environmental Protection","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142274478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-16DOI: 10.1016/j.psep.2024.09.020
This study employs Random Forests (RF) and Artificial Neural Networks (ANN) to model the transient behavior of Ni catalyst deactivation during steam and dry reforming of model biogas containing H2S, with a focus on hydrogen production. Deactivation, induced by carbon deposition and sulfur poisoning, is a complex and transient phenomenon demanding precise kinetic mechanisms for accurately predicting Ni catalyst behavior in biogas reforming. Black-box machine learning (ML) models are developed, incorporating catalyst properties, biogas composition, and operating conditions. Encompassing both dry and steam reforming, the ML models aim to predict catalyst behavior, expressed in terms of packed bed reactor exit mole fractions (H2, CO, CH4, and CO2) and conversions (CH4 and CO2). The ML models are trained and tested across a temperature range of 700–900 C with 0–145 ppm of H2S in model biogas (CH4/CO2 ratio varying from 1.0 to 2.0). RF outperforms the ANN across all performance metrics, including overall R2 and root mean squared error (RMSE). The RF achieves a mean overall R2 of 0.979, with training and testing RMSE equal to and respectively. In contrast, the ANN achieves a mean overall R2 of 0.939, with training and testing RMSE equal to and respectively. Moreover, pre-trained RF models are validated with unseen data of dry reforming of biogas containing 30 ppm of H2S (25 data points). It is suggested that 35 % of this unseen experimental data is required to train the RF model for it to predict catalyst deactivation, achieving a validation R sufficiently2> 0.9. The mean overall R2 values attained by the RF fine-tuned on 35 % of the unseen experiment data for both CH4 and CO2 conversions, as well as for all mole fraction predictions, are 0.952 and 0.948, respectively.
{"title":"Predicting nickel catalyst deactivation in biogas steam and dry reforming for hydrogen production using machine learning","authors":"","doi":"10.1016/j.psep.2024.09.020","DOIUrl":"10.1016/j.psep.2024.09.020","url":null,"abstract":"<div><div>This study employs Random Forests (RF) and Artificial Neural Networks (ANN) to model the transient behavior of Ni catalyst deactivation during steam and dry reforming of model biogas containing H<sub>2</sub>S, with a focus on hydrogen production. Deactivation, induced by carbon deposition and sulfur poisoning, is a complex and transient phenomenon demanding precise kinetic mechanisms for accurately predicting Ni catalyst behavior in biogas reforming. Black-box machine learning (ML) models are developed, incorporating catalyst properties, biogas composition, and operating conditions. Encompassing both dry and steam reforming, the ML models aim to predict catalyst behavior, expressed in terms of packed bed reactor exit mole fractions (H<sub>2</sub>, CO, CH<sub>4</sub>, and CO<sub>2</sub>) and conversions (CH<sub>4</sub> and CO<sub>2</sub>). The ML models are trained and tested across a temperature range of 700–900 C with 0–145 ppm of H<sub>2</sub>S in model biogas (CH<sub>4</sub>/CO<sub>2</sub> ratio varying from 1.0 to 2.0). RF outperforms the ANN across all performance metrics, including overall R<sup>2</sup> and root mean squared error (RMSE). The RF achieves a mean overall R<sup>2</sup> of 0.979, with training and testing RMSE equal to <span><math><mrow><mn>6.7</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></math></span> and <span><math><mrow><mn>1.47</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math></span> respectively. In contrast, the ANN achieves a mean overall R<sup>2</sup> of 0.939, with training and testing RMSE equal to <span><math><mrow><mn>2.6</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math></span> and <span><math><mrow><mn>2.55</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></mrow></math></span> respectively. Moreover, pre-trained RF models are validated with unseen data of dry reforming of biogas containing 30 ppm of H<sub>2</sub>S (25 data points). It is suggested that 35 % of this unseen experimental data is required to train the RF model for it to predict catalyst deactivation, achieving a validation R sufficiently<sup>2</sup>> 0.9. The mean overall R<sup>2</sup> values attained by the RF fine-tuned on 35 % of the unseen experiment data for both CH<sub>4</sub> and CO<sub>2</sub> conversions, as well as for all mole fraction predictions, are 0.952 and 0.948, respectively.</div></div>","PeriodicalId":20743,"journal":{"name":"Process Safety and Environmental Protection","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-16DOI: 10.1016/j.psep.2024.09.065
Molecular dynamics (MD) simulation was carried out to investigate the diffusion behaviors of NH3 and flue gases on CeO2-TiO2 (CT) catalyst for the selective catalytic reduction of NO with NH3. The influence of temperature, gas mixtures, and slit width of catalyst on the diffusivity of the target molecules were studied. The results showed that both temperature and the competitive diffusion of the target molecules substantially impact gas diffusion within nano-slits. The NH3 diffusion was demonstrated to have heightened sensitivity to temperature fluctuations. SO2 showed the greatest hindering effect in all of five gases. The negative effect on NH3 diffusion was greater when H2O existed in the form of hydroxyl groups. Increasing the slit distance of catalyst significantly mitigated this effect, with a decrease in diffusion impedance from 32.51 % to 5.01 % as the distance expanded from 2.5 nm to 7.5 nm. As for NO, a similar suppressive effect was observed when mixed with SO2, but the influence of hydroxyl groups was notably less pronounced compared to NH3. Specifically, there was only a decrease of 15.14 % at a distance of 2.5 nm, followed by almost no decrease when the distance was increased to 7.5 nm.
{"title":"Mass transfer characteristics of multi-pollutants in nano-pores of CeO2-TiO2 based SCR catalyst: A molecular dynamics study","authors":"","doi":"10.1016/j.psep.2024.09.065","DOIUrl":"10.1016/j.psep.2024.09.065","url":null,"abstract":"<div><div>Molecular dynamics (MD) simulation was carried out to investigate the diffusion behaviors of NH<sub>3</sub> and flue gases on CeO<sub>2</sub>-TiO<sub>2</sub> (CT) catalyst for the selective catalytic reduction of NO with NH<sub>3</sub>. The influence of temperature, gas mixtures, and slit width of catalyst on the diffusivity of the target molecules were studied. The results showed that both temperature and the competitive diffusion of the target molecules substantially impact gas diffusion within nano-slits. The NH<sub>3</sub> diffusion was demonstrated to have heightened sensitivity to temperature fluctuations. SO<sub>2</sub> showed the greatest hindering effect in all of five gases. The negative effect on NH<sub>3</sub> diffusion was greater when H<sub>2</sub>O existed in the form of hydroxyl groups. Increasing the slit distance of catalyst significantly mitigated this effect, with a decrease in diffusion impedance from 32.51 % to 5.01 % as the distance expanded from 2.5 nm to 7.5 nm. As for NO, a similar suppressive effect was observed when mixed with SO<sub>2</sub>, but the influence of hydroxyl groups was notably less pronounced compared to NH<sub>3</sub>. Specifically, there was only a decrease of 15.14 % at a distance of 2.5 nm, followed by almost no decrease when the distance was increased to 7.5 nm.</div></div>","PeriodicalId":20743,"journal":{"name":"Process Safety and Environmental Protection","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-16DOI: 10.1016/j.psep.2024.09.064
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 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.
{"title":"Unveiling the synergism and reaction pathway of ethyl acetate removal in DBD/absorption integrated reactor","authors":"","doi":"10.1016/j.psep.2024.09.064","DOIUrl":"10.1016/j.psep.2024.09.064","url":null,"abstract":"<div><div>The experiment employs dielectric barrier discharge (DBD) combined with absorption integrated reactor (DCA<sup>IR</sup>) for higher concentration ethyl acetate removal and studies the synergism of DCA<sup>IR</sup> technology and the reaction pathway of ethyl acetate. Among three technologies of DCA<sup>IR</sup>, DBD and DBD combined with absorption series reactor (DCA<sup>SR</sup>), DCA<sup>IR</sup> achieved the highest removal efficiency (RE) of ethyl acetate at similar input power. Fixed gas flow rate of 1000 ml/min and <span><math><msubsup><mrow><mi>c</mi></mrow><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>4</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>8</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mrow><mi>in</mi></mrow></msubsup></math></span> of 5000 mg/m<sup>3</sup>, the average REs of DCA<sup>SR</sup> and DCA<sup>IR</sup> are higher than that of DBD by 31.2 % and 34.2 %, respectively. For the efficiency compensation mechanism, one of synergies in DCA<sup>IR</sup>, 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 (DCA<sup>IR</sup>) > 5.1 g/kWh (DCA<sup>SR</sup>) > 3.0 g/kWh (DBD). Tail gas and absorbent analysis reveals DCA<sup>IR</sup> can enhance mineralizing ethyl acetate and eliminating the secondary pollutants (e.g., O<sub>3</sub>, 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 DCA<sup>IR</sup> has been unveiled.</div></div>","PeriodicalId":20743,"journal":{"name":"Process Safety and Environmental Protection","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-15DOI: 10.1016/j.psep.2024.09.045
Diamond wire saw silicon powder (DWSSP) waste is a highly promising secondary resource for recycling high-purity silicon, which is crucial for the sustainable development of the photovoltaic (PV) industry. However, because DWSSP is prone to oxidation, the purity and yield of the recovered silicon are generally low. In this study, the oxidation mechanism of DWSSP in water was systematically investigated, and kinetics analysis and microstructure analysis were conducted to determine the relationship between water diffusion and the growth of the oxide layer. The results indicated that oxidation was determined by the kinetic parameter b in the Reisman model. At T < 328 K and particle size > 1.56 μm, b was less than 1, indicating that the oxidation process was governed by the diffusion of H2O molecules. Through temperature regulation to achieve b < 1, the oxidation was inhibited, which could enhance recovery efficiency. Overall, this study demonstrated the feasibility of inhibiting oxidation by regulating the viscous flow of SiO2 molecules to promote the recycling of silicon resources and support sustainable development.
{"title":"Promotion of silicon–oxygen control and green sustainable recovery from diamond wire saw silicon powder waste based on the viscous flow mechanism","authors":"","doi":"10.1016/j.psep.2024.09.045","DOIUrl":"10.1016/j.psep.2024.09.045","url":null,"abstract":"<div><p>Diamond wire saw silicon powder (DWSSP) waste is a highly promising secondary resource for recycling high-purity silicon, which is crucial for the sustainable development of the photovoltaic (PV) industry. However, because DWSSP is prone to oxidation, the purity and yield of the recovered silicon are generally low. In this study, the oxidation mechanism of DWSSP in water was systematically investigated, and kinetics analysis and microstructure analysis were conducted to determine the relationship between water diffusion and the growth of the oxide layer. The results indicated that oxidation was determined by the kinetic parameter <em>b</em> in the Reisman model. At <em>T</em> < 328 K and particle size > 1.56 μm, <em>b</em> was less than 1, indicating that the oxidation process was governed by the diffusion of H<sub>2</sub>O molecules. Through temperature regulation to achieve <em>b</em> < 1, the oxidation was inhibited, which could enhance recovery efficiency. Overall, this study demonstrated the feasibility of inhibiting oxidation by regulating the viscous flow of SiO<sub>2</sub> molecules to promote the recycling of silicon resources and support sustainable development.</p></div>","PeriodicalId":20743,"journal":{"name":"Process Safety and Environmental Protection","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-15DOI: 10.1016/j.psep.2024.09.022
In the current study, numerical study of vented hydrogen explosions was performed utilizing computational fluid dynamics (CFD) software GASFLOW-MPI. A turbulent combustion model based on Schmidt correlation was formulated. Within this model, flame instabilities resulted from two intrinsic effects, Hydrodynamic instability, and Landau-Darrieus and Thermal-Diffusive instabilities were incorporated. The numerical simulation results revealed the mechanism of overpressure evolution inside and outside the vessel. Notably, the mechanism of the overpressure peak induced by the external explosion was revealed. The effects of turbulence models on overpressure time profiles were investigated. Moreover, it was determined that heat transfer, arising from thermal radiation and convection, exerts only a negligible influence on the maximum internal overpressure. Subsequently, the performance of GASFLOW-MPI in simulating vented hydrogen explosions for different ignition locations (center and rear ignitions) and varying hydrogen concentrations (22%-38%) was assessed against experimental data. Comparative analysis revealed a close agreement between the predicted results and experimental data. Furthermore, the competency of GASFLOW in simulating medium-scale vented hydrogen explosions was validated against experimental data.
{"title":"Numerical study of external explosion in vented hydrogen explosions","authors":"","doi":"10.1016/j.psep.2024.09.022","DOIUrl":"10.1016/j.psep.2024.09.022","url":null,"abstract":"<div><p>In the current study, numerical study of vented hydrogen explosions was performed utilizing computational fluid dynamics (CFD) software GASFLOW-MPI. A turbulent combustion model based on Schmidt correlation was formulated. Within this model, flame instabilities resulted from two intrinsic effects, Hydrodynamic instability, and Landau-Darrieus and Thermal-Diffusive instabilities were incorporated. The numerical simulation results revealed the mechanism of overpressure evolution inside and outside the vessel. Notably, the mechanism of the overpressure peak induced by the external explosion was revealed. The effects of turbulence models on overpressure time profiles were investigated. Moreover, it was determined that heat transfer, arising from thermal radiation and convection, exerts only a negligible influence on the maximum internal overpressure. Subsequently, the performance of GASFLOW-MPI in simulating vented hydrogen explosions for different ignition locations (center and rear ignitions) and varying hydrogen concentrations (22%-38%) was assessed against experimental data. Comparative analysis revealed a close agreement between the predicted results and experimental data. Furthermore, the competency of GASFLOW in simulating medium-scale vented hydrogen explosions was validated against experimental data.</p></div>","PeriodicalId":20743,"journal":{"name":"Process Safety and Environmental Protection","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142274481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-14DOI: 10.1016/j.psep.2024.09.055
Recently, solid iron sources have been used for scorodite synthesis in arsenic-bearing wastewater from nonferrous metallurgy. Immobilising arsenic-solution as scorodite via iron hydroxide (Fe(OH)3) solid iron source is an important method for controlling arsenic pollution. The evolution behavior of scorodite during its formation in high arsenic solution have been rarely investigated. In this paper, the mechanism and kinetics of scorodite formation using Fe(OH)3 in arsenic-bearing solution were investigated. This work was divided into three parts. Firstly, the influencing parameters were investigated, revealing that the dissolution of Fe(OH)3 and scorodite generation accelerated at lower initial pH and higher reaction temperature. Increasing Fe/As ratio delayed scorodite crystallisation, which was in turn enhanced by elevating arsenic concentration. Secondly, the mechanism of scorodite formation was investigated, revealing that Fe(OH)3 underwent acidic dissolution to form a precursor. Subsequent scorodite formation had a ΔrGmθ ranging from −69.39 kJ·mol−1 to −15.64 kJ·mol−1. Residual As was absorbed and converted into Fe(OH)3@scorodite. Thirdly, the chemical kinetics were investigated, showing that activation energy (Ea) for Fe(OH)3 dissolution was 72.54 and 105.37 kJ·mol−1 at Stages I and II, respectively, whereas it was 105.97 kJ·mol−1 for residual As absorption-conversion at Stage III outweighing the Ea of As-Fe coprecipitation. The restrictive steps were Fe(OH)3 dissolution and residual arsenic absorption-conversion. This proposed method can be applied for environment-friendly treatment of 10－40 g/L of arsenic-bearing industrial effluent for scorodite formation. Overall, this research confirmed the formation of scorodite via Fe(OH)3 and can potentially provide feasible schemes for eliminating arsenic-bearing acidic waste, dust, and anode slime from nonferrous metallurgical processes.
{"title":"Mechanism and kinetics of scorodite formation in arsenic-bearing solutions using Fe(OH)3 as a solid iron source","authors":"","doi":"10.1016/j.psep.2024.09.055","DOIUrl":"10.1016/j.psep.2024.09.055","url":null,"abstract":"<div><p>Recently, solid iron sources have been used for scorodite synthesis in arsenic-bearing wastewater from nonferrous metallurgy. Immobilising arsenic-solution as scorodite via iron hydroxide (Fe(OH)<sub>3</sub>) solid iron source is an important method for controlling arsenic pollution. The evolution behavior of scorodite during its formation in high arsenic solution have been rarely investigated. In this paper, the mechanism and kinetics of scorodite formation using Fe(OH)<sub>3</sub> in arsenic-bearing solution were investigated. This work was divided into three parts. Firstly, the influencing parameters were investigated, revealing that the dissolution of Fe(OH)<sub>3</sub> and scorodite generation accelerated at lower initial pH and higher reaction temperature. Increasing Fe/As ratio delayed scorodite crystallisation, which was in turn enhanced by elevating arsenic concentration. Secondly, the mechanism of scorodite formation was investigated, revealing that Fe(OH)<sub>3</sub> underwent acidic dissolution to form a precursor. Subsequent scorodite formation had a Δ<sub>r</sub>G<sub>m</sub><sup>θ</sup> ranging from −69.39 kJ·mol<sup>−1</sup> to −15.64 kJ·mol<sup>−1</sup>. Residual As was absorbed and converted into Fe(OH)<sub>3</sub>@scorodite. Thirdly, the chemical kinetics were investigated, showing that activation energy (Ea) for Fe(OH)<sub>3</sub> dissolution was 72.54 and 105.37 kJ·mol<sup>−1</sup> at Stages I and II, respectively, whereas it was 105.97 kJ·mol<sup>−1</sup> for residual As absorption-conversion at Stage III outweighing the Ea of As-Fe coprecipitation. The restrictive steps were Fe(OH)<sub>3</sub> dissolution and residual arsenic absorption-conversion. This proposed method can be applied for environment-friendly treatment of 10－40 g/L of arsenic-bearing industrial effluent for scorodite formation. Overall, this research confirmed the formation of scorodite via Fe(OH)<sub>3</sub> and can potentially provide feasible schemes for eliminating arsenic-bearing acidic waste, dust, and anode slime from nonferrous metallurgical processes.</p></div>","PeriodicalId":20743,"journal":{"name":"Process Safety and Environmental Protection","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-14DOI: 10.1016/j.psep.2024.09.049
<div><p>The atmospheric particulate pollution poses a serious threat to human health and ecological environment. The dust particle pollution caused by the operation of agricultural machinery is becoming increasingly severe and the peanut pickup harvesters are widely used in agricultural operation. Therefore, it is necessary to reduce the concentration of dust particles in the work of peanut pickup harvesters. In this study, a self-designed dust-fall box composed of multipleaxial flow cyclone tubes in parallel was integrated with the peanut pickup harvester. Based on the CFD-DPM model, simulation analysis was conducted to explore the effects of different inlet velocities, different numbers of swirling blades, and two types of exhaust port on the dust removal performance of the cyclone. The Box-Behnken design was used to determine the optimal structural parameters of the axial flow cyclone. The influence of the pressure distribution and velocity variations of the internal flow field on the dust removal efficiency of the two schemes was simulated and analyzed. Thereafter, a reasonable parallel scheme of multiple axial flow cyclone tubes in the dust-fall box was determined. The drone was used to monitor dust in peanut harvesting operations, and dust particle concentrations at 8 detection points under varying working conditions were recorded. The distribution and diffusion rules of dust in harvesting operations were explored through cluster analysis, and the test data obtained were compared with numerical calculation results to verify the accuracy of numerical calculation. The results showed that for a single axial flow cyclone, when the inlet wind speed was 6 m/s to 8 m/s and the number of swirling blades was 4, the structural parameters of the cyclone separator had significant influence on the separation efficiency. The influencing factors ranking in descending order were cylinder diameter, cylinder length, and exhaust pipe insertion depth, respectively. To be more precisely, the separation efficiency was best when the cylinder diameter was 60 mm, the cylinder length was 150 mm, the insertion depth of the exhaust pipe was 50 mm and the cone angle was 20°. It was more reasonable to use 8 axial flow cyclone tubes in parallel, and the maximum separation efficiency can reach 84.21 %. Field operations showed that the numerical calculation results were similar to the actual harvesting process. The dust particle concentration in the peanut harvesting operation equipped with a dust-fall box was always lower than 10 mg/m<sup>3</sup>. The dust particle concentration was the highest at the rear of the whole machine and the lowest near the cab. Compared conventional harvesters, the harvester with a dust-fall box reduced its dust particle concentration by 64.37 %; the concentration of 30 μm dust particles was reduced by 69.31 %; the dust particle concentration at the rear of the whole machine also effectively reduced. This study can provide reference for control
{"title":"Analysis of the influence of dust particles in the peanut pickup harvester with a self-designed axial-flow dust-fall box on its dust suppression performance","authors":"","doi":"10.1016/j.psep.2024.09.049","DOIUrl":"10.1016/j.psep.2024.09.049","url":null,"abstract":"<div><p>The atmospheric particulate pollution poses a serious threat to human health and ecological environment. The dust particle pollution caused by the operation of agricultural machinery is becoming increasingly severe and the peanut pickup harvesters are widely used in agricultural operation. Therefore, it is necessary to reduce the concentration of dust particles in the work of peanut pickup harvesters. In this study, a self-designed dust-fall box composed of multipleaxial flow cyclone tubes in parallel was integrated with the peanut pickup harvester. Based on the CFD-DPM model, simulation analysis was conducted to explore the effects of different inlet velocities, different numbers of swirling blades, and two types of exhaust port on the dust removal performance of the cyclone. The Box-Behnken design was used to determine the optimal structural parameters of the axial flow cyclone. The influence of the pressure distribution and velocity variations of the internal flow field on the dust removal efficiency of the two schemes was simulated and analyzed. Thereafter, a reasonable parallel scheme of multiple axial flow cyclone tubes in the dust-fall box was determined. The drone was used to monitor dust in peanut harvesting operations, and dust particle concentrations at 8 detection points under varying working conditions were recorded. The distribution and diffusion rules of dust in harvesting operations were explored through cluster analysis, and the test data obtained were compared with numerical calculation results to verify the accuracy of numerical calculation. The results showed that for a single axial flow cyclone, when the inlet wind speed was 6 m/s to 8 m/s and the number of swirling blades was 4, the structural parameters of the cyclone separator had significant influence on the separation efficiency. The influencing factors ranking in descending order were cylinder diameter, cylinder length, and exhaust pipe insertion depth, respectively. To be more precisely, the separation efficiency was best when the cylinder diameter was 60 mm, the cylinder length was 150 mm, the insertion depth of the exhaust pipe was 50 mm and the cone angle was 20°. It was more reasonable to use 8 axial flow cyclone tubes in parallel, and the maximum separation efficiency can reach 84.21 %. Field operations showed that the numerical calculation results were similar to the actual harvesting process. The dust particle concentration in the peanut harvesting operation equipped with a dust-fall box was always lower than 10 mg/m<sup>3</sup>. The dust particle concentration was the highest at the rear of the whole machine and the lowest near the cab. Compared conventional harvesters, the harvester with a dust-fall box reduced its dust particle concentration by 64.37 %; the concentration of 30 μm dust particles was reduced by 69.31 %; the dust particle concentration at the rear of the whole machine also effectively reduced. This study can provide reference for control","PeriodicalId":20743,"journal":{"name":"Process Safety and Environmental Protection","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-14DOI: 10.1016/j.psep.2024.09.032
Microbial electrolysis cells (MECs) have garnered significant attention for their potential in sustainable hydrogen production and wastewater treatment. Due to their unique electrochemical properties, molybdenum-based compounds have emerged as promising candidates among various cathode materials. This review explores the multifaceted role of molybdenum in MECs, focusing on its catalytic performance, synthesis strategies, and potential for enhancing H2 evolution reactions. Various molybdenum-based materials, including molybdenum disulfide (MoS2), molybdenum phosphide (MoP), molybdenum carbide (Mo2C), and nickel-molybdenum alloys (NiMo), are discussed in terms of their synthesis methods, electrochemical performance, and scalability. Notably, molybdenum-based electrodes have demonstrated comparable or superior catalytic activity to traditional platinum-based cathodes, highlighting their potential as cost-effective alternatives. Future directions in this field include further optimization of synthesis methods, exploration of new molybdenum-based cathodes, mechanistic understanding of catalytic activity, and addressing scalability and stability challenges. Overall, molybdenum-based materials present promising opportunities for advancing MECs technology, driving progress toward sustainable hydrogen production and wastewater treatment.
{"title":"Molybdenum as cathode materials: Paving the way for sustainable biohydrogen production in microbial electrolysis cells","authors":"","doi":"10.1016/j.psep.2024.09.032","DOIUrl":"10.1016/j.psep.2024.09.032","url":null,"abstract":"<div><div>Microbial electrolysis cells (MECs) have garnered significant attention for their potential in sustainable hydrogen production and wastewater treatment. Due to their unique electrochemical properties, molybdenum-based compounds have emerged as promising candidates among various cathode materials. This review explores the multifaceted role of molybdenum in MECs, focusing on its catalytic performance, synthesis strategies, and potential for enhancing H<sub>2</sub> evolution reactions. Various molybdenum-based materials, including molybdenum disulfide (MoS<sub>2</sub>), molybdenum phosphide (MoP), molybdenum carbide (Mo<sub>2</sub>C), and nickel-molybdenum alloys (NiMo), are discussed in terms of their synthesis methods, electrochemical performance, and scalability. Notably, molybdenum-based electrodes have demonstrated comparable or superior catalytic activity to traditional platinum-based cathodes, highlighting their potential as cost-effective alternatives. Future directions in this field include further optimization of synthesis methods, exploration of new molybdenum-based cathodes, mechanistic understanding of catalytic activity, and addressing scalability and stability challenges. Overall, molybdenum-based materials present promising opportunities for advancing MECs technology, driving progress toward sustainable hydrogen production and wastewater treatment.</div></div>","PeriodicalId":20743,"journal":{"name":"Process Safety and Environmental Protection","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-14DOI: 10.1016/j.psep.2024.09.046
Van Giao Nguyen, Prabhakar Sharma, Bhaskor Jyoti Bora, Thi Minh Tu Bui, Cristina Efremov, Minh Ho Tran, Jerzy Kowalski, Sameh M. Osman, Dao Nam Cao, Van Huong Dong
The electrification of off-grid /island villages is a critical step towards improving the techno-economic circumstances of rural regions and the overall general growth of the country. However, consistent supply from a single source is not possible in these areas. Thus, a hybrid renewable energy system performs better in these conditions. The research challenge now is to identify the optimal combinations of HRES from the available resources in a specific village site that can supply the power demand sustainably and to determine whether this is a cost-effective option. The present work is an endeavour to develop a sustainable and dynamic energy demand-supply model using HOMER Pro energy software in a specified off-grid rural site in Vietnam. The research presents four unique configurations of a combined energy system for Vietnam's island settlements, incorporating biomass-based biogas facilities, photovoltaic panels, lithium-ion batteries, and converters. Homer Pro was used for optimization and design, focusing on key performance measures such as cost of energy, net present cost, initial cost, operating cost, renewable fraction, and carbon emissions. The best HES system layout includes a 100-kW biomass-based generator, 2.62 kW photovoltaic installation, 10 lithium-ion batteries, and a 6.31 kW converter, producing 100 % renewable energy. The system's low cost of energy ($0.48), and net present cost ($25,730.89) make it an economically viable alternative, while its low CO2 emissions demonstrate its commitment to reducing greenhouse gas emissions.
离网/岛屿村庄电气化是改善农村地区技术经济状况和国家整体发展的关键一步。然而，在这些地区不可能从单一来源持续供电。因此，混合可再生能源系统在这些条件下能发挥更好的作用。目前的研究挑战是如何从特定村落的可用资源中找出可持续满足电力需求的混合可再生能源系统的最佳组合，并确定这是否是一种具有成本效益的选择。本研究致力于在越南的一个特定离网农村地区，利用 HOMER Pro 能源软件开发一个可持续的动态能源供需模型。研究为越南的岛屿居住区提出了四种独特的组合能源系统配置，其中包括生物质沼气设施、光伏电池板、锂离子电池和转换器。Homer Pro 用于优化和设计，重点关注能源成本、净现值成本、初始成本、运营成本、可再生部分和碳排放等关键性能指标。最佳 HES 系统布局包括一个 100 千瓦的生物质发电机、2.62 千瓦的光伏装置、10 个锂离子电池和一个 6.31 千瓦的转换器，可产生 100% 的可再生能源。该系统的低能源成本（0.48 美元）和净现值成本（25,730.89 美元）使其成为经济上可行的替代方案，而其低二氧化碳排放量则证明了其对减少温室气体排放的承诺。
{"title":"Techno-economic analysis of a hybrid energy system for electrification using an off-grid solar/biogas/battery system employing HOMER: A case study in Vietnam","authors":"Van Giao Nguyen, Prabhakar Sharma, Bhaskor Jyoti Bora, Thi Minh Tu Bui, Cristina Efremov, Minh Ho Tran, Jerzy Kowalski, Sameh M. Osman, Dao Nam Cao, Van Huong Dong","doi":"10.1016/j.psep.2024.09.046","DOIUrl":"https://doi.org/10.1016/j.psep.2024.09.046","url":null,"abstract":"The electrification of off-grid /island villages is a critical step towards improving the techno-economic circumstances of rural regions and the overall general growth of the country. However, consistent supply from a single source is not possible in these areas. Thus, a hybrid renewable energy system performs better in these conditions. The research challenge now is to identify the optimal combinations of HRES from the available resources in a specific village site that can supply the power demand sustainably and to determine whether this is a cost-effective option. The present work is an endeavour to develop a sustainable and dynamic energy demand-supply model using HOMER Pro energy software in a specified off-grid rural site in Vietnam. The research presents four unique configurations of a combined energy system for Vietnam's island settlements, incorporating biomass-based biogas facilities, photovoltaic panels, lithium-ion batteries, and converters. Homer Pro was used for optimization and design, focusing on key performance measures such as cost of energy, net present cost, initial cost, operating cost, renewable fraction, and carbon emissions. The best HES system layout includes a 100-kW biomass-based generator, 2.62 kW photovoltaic installation, 10 lithium-ion batteries, and a 6.31 kW converter, producing 100 % renewable energy. The system's low cost of energy ($0.48), and net present cost ($25,730.89) make it an economically viable alternative, while its low CO<ce:inf loc=\"post\">2</ce:inf> emissions demonstrate its commitment to reducing greenhouse gas emissions.","PeriodicalId":20743,"journal":{"name":"Process Safety and Environmental Protection","volume":null,"pages":null},"PeriodicalIF":7.8,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142275706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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