This work aims to study the improvement effect of Sm on Mn-based catalysts for selective catalytic reduction (SCR) of NO with NH3.A series of Sm_(x)Mn_(0.3-x)-xTi catalysts (x=0,0.1,0.15,0.2,and 0.3) were prepared by ...This work aims to study the improvement effect of Sm on Mn-based catalysts for selective catalytic reduction (SCR) of NO with NH3.A series of Sm_(x)Mn_(0.3-x)-xTi catalysts (x=0,0.1,0.15,0.2,and 0.3) were prepared by co-precipitation.Activity tests indicated that the Sm_(0.15)Mn_(0.15)Ti catalyst showed superior performances,with a NO conversion of 100%and N_(2)selectivity above 87%at 180–300℃.The characterizations showed that Sm doping suppressed the crystallization of TiO_(2)and Mn2O3phases and increased the specific surface area and acidity.In particular,the surface area increased from 152.2 m^(2)·g^(-1)for Mn0.3Ti to 241.7 m^(2)·g^(-1)for Sm_(0.15)Mn_(0.15)Ti.These effects contributed to the high catalytic activity.The X-ray photoelectron spectroscopy (XPS) results indicated that the relative atomic ratios of Sm^(3+)/Sm and Oβ/O of Sm_(0.15)Mn_(0.15)Ti were 76.77at%and 44.11at%,respectively.The presence of Sm contributed to an increase in surface-absorbed oxygen (Oβ) and a decrease in Mn^(4+)surface concentration,which improved the catalytic activity.In the results of hydrogen temperature-programmed reduction(H_(2)-TPR),the presence of Sm induced a higher reduction temperature and lower H_(2)consumption (0.3 mmol·g^(-1)) for the Sm_(0.15)Mn_(0.15)Ti catalyst compared to the Mn0.3Ti catalyst.The decrease in Mn^(4+)weakened the redox property of the catalysts and increased the N_(2)selectivity by suppressing N_(2)O formation from NH3oxidation and the nonselective catalytic reduction reaction.The in situ diffuse reflectance infrared Fourier transform spectra (DRIFTs) revealed that NH3-SCR of NO over the Sm_(0.15)Mn_(0.15)Ti catalyst mainly followed the Eley–Rideal mechanism.Sm doping increased surface-absorbed oxygen and weakened the redox property to improve the NO conversion and N_(2)selectivity of the Sm_(0.15)Mn_(0.15)Ti catalyst.展开更多
Electrocatalysis for nitrate(NO_(3^(–)))removal from wastewater faces the challenge of merging efficient reduction and high selectivity to nitrogen(N2)with economic viability in a durable catalyst.In this study,bimet...Electrocatalysis for nitrate(NO_(3^(–)))removal from wastewater faces the challenge of merging efficient reduction and high selectivity to nitrogen(N2)with economic viability in a durable catalyst.In this study,bimetallic PdCu/TiO_(x)composite catalysts were synthesized with varying Pd and Cu ratios through electrochemical deposition on defective TiOxnanotube arrays.Denitrification experiments demonstrated that the Pd_(1)Cu_(1)/TiO_(x)catalyst exhibited the highest(NO_(3^(–)))removal rate(81.2%)and N_(2)selectivity(67.2%)among all tested catalysts.Leveraging the exceptional light-responsive property of TiO_(x),the introduction of light energy as an assisting factor in electrocatalysis further augmented the(NO_(3^(–)))treatment rate,resulting in a higher(NO_(3^(–)))removal rate of 95.1%and N_(2)selectivity of approximately 90%.Compared to individual electrocatalysis and photocatalysis systems,the overpotential for the catalytic interface active*H formation in the photo-assisted electrocatalysis system was remarkably reduced,thus accelerating electron migration and promoting(NO_(3^(–)))reduction kinetics.Economic analysis revealed an energy consumption of 2.74 k Wh/mol and a corresponding energy consumption per order(EEO)of 0.79 k Wh/m^(3)for the Pd_(1)Cu_(1)/TiOxcatalyst to reduce 25.2 mg/L of(NO_(3^(–)))-N in water to N_(2),showcasing remarkable competitiveness and economic advantages over other water treatment technologies.This study developed the PdCu/TiOxelectrocatalysts with high(NO_(3^(–)))removal rates and N_(2)selectivity,particularly when combined with light energy,the efficiency and selectivity were significantly enhanced,offering a competitive and economically viable solution for wastewater treatment.展开更多
With the global advancement of the circular economy,integrating reverse osmosis(RO)or forward osmosis(FO)with anaerobic membrane bioreactor(AnMBR)offers a promising approach to simultaneously generate high-grade recla...With the global advancement of the circular economy,integrating reverse osmosis(RO)or forward osmosis(FO)with anaerobic membrane bioreactor(AnMBR)offers a promising approach to simultaneously generate high-grade reclaimed water,produce energy,and preserve valuable nutrients from municipal wastewater.However,the selectivity of these osmotic membranes towards ammonia nitrogen,a major component in municipal wastewater and anaerobic effluent,remains unsatisfactory due to its similar polarity and hydraulic radius to water molecules.Therefore,enhancing the ammonia nitrogen rejection of osmotic membranes is imperative to maximize the quality of reclaimed water and minimize the loss of ammonia nitrogen resources.Unfortunately,the current understanding of the mapping relationship between ammonia nitrogen transmembrane diffusion and the micro/nano-structure of osmotic membranes is not systematic,making precise optimization of the membranes challenging.Hence,this review comprehensively analyzed the diffusion behavior of ammonia nitrogen through osmotic membranes to lay the foundation for targeted regulation of membrane fine structure.Initially,the desire for ammonia/ammonium-rejecting membranes was highlighted by introducing current and promising osmotic membrane-based applications in municipal wastewater reclamation processes.Subsequently,the connection between the micro/nano-structure of osmotic membranes and the transmembrane diffusion behavior of ammonia nitrogen was explored by analyzing the effects of membrane characteristics on ammonia nitrogen transport using the DSPM-DE model.Finally,precise methods for modifying membranes to enhance ammonia nitrogen rejection were proposed.This review aims to offer theoretical insights guiding the development of RO and FO membranes with superior ammonia nitrogen rejection for efficient reclamation of municipal wastewater.展开更多
基金sponsored by the National Key R&D Program of China(Nos.2021YFC1910504,2019YFC 1907101,and 2019YFC1907103)the Key R&D Program of Ningxia Hui Autonomous Region,China(Nos.2020BCE01001 and 2021BEG01003)+3 种基金the National Natural Science Foundation of China(Nos.U2002212,51672024,52102058,and 52204414)the Xijiang Innovation and Entrepreneurship Team(No.2017A0109004)the Fundamental Research Funds for the Central Universities(Nos.FRF-TP20-097A1Z and FRF-TP-20-031A1)the Foshan Science and Technology Innovation Special Foundation(No.BK22BE001)。
文摘This work aims to study the improvement effect of Sm on Mn-based catalysts for selective catalytic reduction (SCR) of NO with NH3.A series of Sm_(x)Mn_(0.3-x)-xTi catalysts (x=0,0.1,0.15,0.2,and 0.3) were prepared by co-precipitation.Activity tests indicated that the Sm_(0.15)Mn_(0.15)Ti catalyst showed superior performances,with a NO conversion of 100%and N_(2)selectivity above 87%at 180–300℃.The characterizations showed that Sm doping suppressed the crystallization of TiO_(2)and Mn2O3phases and increased the specific surface area and acidity.In particular,the surface area increased from 152.2 m^(2)·g^(-1)for Mn0.3Ti to 241.7 m^(2)·g^(-1)for Sm_(0.15)Mn_(0.15)Ti.These effects contributed to the high catalytic activity.The X-ray photoelectron spectroscopy (XPS) results indicated that the relative atomic ratios of Sm^(3+)/Sm and Oβ/O of Sm_(0.15)Mn_(0.15)Ti were 76.77at%and 44.11at%,respectively.The presence of Sm contributed to an increase in surface-absorbed oxygen (Oβ) and a decrease in Mn^(4+)surface concentration,which improved the catalytic activity.In the results of hydrogen temperature-programmed reduction(H_(2)-TPR),the presence of Sm induced a higher reduction temperature and lower H_(2)consumption (0.3 mmol·g^(-1)) for the Sm_(0.15)Mn_(0.15)Ti catalyst compared to the Mn0.3Ti catalyst.The decrease in Mn^(4+)weakened the redox property of the catalysts and increased the N_(2)selectivity by suppressing N_(2)O formation from NH3oxidation and the nonselective catalytic reduction reaction.The in situ diffuse reflectance infrared Fourier transform spectra (DRIFTs) revealed that NH3-SCR of NO over the Sm_(0.15)Mn_(0.15)Ti catalyst mainly followed the Eley–Rideal mechanism.Sm doping increased surface-absorbed oxygen and weakened the redox property to improve the NO conversion and N_(2)selectivity of the Sm_(0.15)Mn_(0.15)Ti catalyst.
基金the National Natural Science Foundation of China(No.52300084)China Postdoctoral Science Foundation(No.2023M741151)the Fundamental Research Funds for the Central Universities(No.2024MS063)。
文摘Electrocatalysis for nitrate(NO_(3^(–)))removal from wastewater faces the challenge of merging efficient reduction and high selectivity to nitrogen(N2)with economic viability in a durable catalyst.In this study,bimetallic PdCu/TiO_(x)composite catalysts were synthesized with varying Pd and Cu ratios through electrochemical deposition on defective TiOxnanotube arrays.Denitrification experiments demonstrated that the Pd_(1)Cu_(1)/TiO_(x)catalyst exhibited the highest(NO_(3^(–)))removal rate(81.2%)and N_(2)selectivity(67.2%)among all tested catalysts.Leveraging the exceptional light-responsive property of TiO_(x),the introduction of light energy as an assisting factor in electrocatalysis further augmented the(NO_(3^(–)))treatment rate,resulting in a higher(NO_(3^(–)))removal rate of 95.1%and N_(2)selectivity of approximately 90%.Compared to individual electrocatalysis and photocatalysis systems,the overpotential for the catalytic interface active*H formation in the photo-assisted electrocatalysis system was remarkably reduced,thus accelerating electron migration and promoting(NO_(3^(–)))reduction kinetics.Economic analysis revealed an energy consumption of 2.74 k Wh/mol and a corresponding energy consumption per order(EEO)of 0.79 k Wh/m^(3)for the Pd_(1)Cu_(1)/TiOxcatalyst to reduce 25.2 mg/L of(NO_(3^(–)))-N in water to N_(2),showcasing remarkable competitiveness and economic advantages over other water treatment technologies.This study developed the PdCu/TiOxelectrocatalysts with high(NO_(3^(–)))removal rates and N_(2)selectivity,particularly when combined with light energy,the efficiency and selectivity were significantly enhanced,offering a competitive and economically viable solution for wastewater treatment.
基金supported by National Natural Science Foundation of China(No.52200051)Harbin Institute of Technology(No.HC202236)Outstanding Youth Fund of Heilongjiang Natural Science Foundation(No.YQ2023E021)。
文摘With the global advancement of the circular economy,integrating reverse osmosis(RO)or forward osmosis(FO)with anaerobic membrane bioreactor(AnMBR)offers a promising approach to simultaneously generate high-grade reclaimed water,produce energy,and preserve valuable nutrients from municipal wastewater.However,the selectivity of these osmotic membranes towards ammonia nitrogen,a major component in municipal wastewater and anaerobic effluent,remains unsatisfactory due to its similar polarity and hydraulic radius to water molecules.Therefore,enhancing the ammonia nitrogen rejection of osmotic membranes is imperative to maximize the quality of reclaimed water and minimize the loss of ammonia nitrogen resources.Unfortunately,the current understanding of the mapping relationship between ammonia nitrogen transmembrane diffusion and the micro/nano-structure of osmotic membranes is not systematic,making precise optimization of the membranes challenging.Hence,this review comprehensively analyzed the diffusion behavior of ammonia nitrogen through osmotic membranes to lay the foundation for targeted regulation of membrane fine structure.Initially,the desire for ammonia/ammonium-rejecting membranes was highlighted by introducing current and promising osmotic membrane-based applications in municipal wastewater reclamation processes.Subsequently,the connection between the micro/nano-structure of osmotic membranes and the transmembrane diffusion behavior of ammonia nitrogen was explored by analyzing the effects of membrane characteristics on ammonia nitrogen transport using the DSPM-DE model.Finally,precise methods for modifying membranes to enhance ammonia nitrogen rejection were proposed.This review aims to offer theoretical insights guiding the development of RO and FO membranes with superior ammonia nitrogen rejection for efficient reclamation of municipal wastewater.
