With extensive attention being paid to the potential environmental hazards of discarded face masks,catalytic pyrolysis technologies have been proposed to realize the valorization of wastes.However,recent catalyst sele...With extensive attention being paid to the potential environmental hazards of discarded face masks,catalytic pyrolysis technologies have been proposed to realize the valorization of wastes.However,recent catalyst selection and system design have focused solely on conversion efficiency,ignoring economic cost and potential life-cycle environmental damage.Here,we propose an economic-environmental hybrid pre-assessment method to help identify catalysts and reactors with less environmental impact and high economic returns among various routes to convert discarded face masks into carbon nanotubes(CNTs)and hydrogen.In catalyst selection,it was found that a widely known Fe-Ni catalyst exhibits higher catalytic activity than a cheaper Fe catalyst,potentially increasing the economic viability of the catalytic pyrolysis system by 38%-55%.The use of this catalyst also results in a carbon reduction of 4.12-10.20kilogram CO_(2) equivalent for 1 kilogram of discarded face masks,compared with the cheaper Fe catalyst.When the price of CNTs exceeds 1.49×10^(4) USD·t^(-1),microwave-assisted pyrolysis is the optimal choice due to its superior environmental performance(in terms of its life-cycle greenhouse gas reduction potential,eutrophication potential,and human toxicity)and economic benefits.In contrast,conventional heating pyrolysis may be a more economical option due to its good stability over 43 reaction regeneration cycles,as compared with a microwave-assisted pyrolysis catalyst with a higher conversion efficiency.This study connects foundational science with ecological economics to guide emerging technologies in their research stage toward technical efficiency,economic benefits,and environmental sustainability.展开更多
Catalytic pyrolysis of digestate to produce aromatic hydrocarbons can be combined with anaerobic fermentation to effectively transform and utilize all biomass components,which can achieve the meaningful purpose of tra...Catalytic pyrolysis of digestate to produce aromatic hydrocarbons can be combined with anaerobic fermentation to effectively transform and utilize all biomass components,which can achieve the meaningful purpose of transforming waste into high-value products.This study explored whether catalytic pyrolysis of digestate is feasible to prepare aromatic hydrocarbons by analyzing the thermogravimetric characteristics,pyrolysis characteristics,and catalytic pyrolysis characteristics of digestate.For digestate pyrolysis,an increase in temperature was found to elevate the CO,CH_4,and monocyclic aromatic hydrocarbon(benzene,toluene,and xylene;BTX)content,whereas it decreased the contents of phenols,acids,aldehydes,and other oxygenates.Furthermore,the catalytic pyrolysis process effectively inhibited the acids,phenols,and furans in the liquid,whereas the yield of BTX increased from 25.45%to 45.99%,and the selectivity of xylene was also increased from 10.32%to 28.72%after adding ZSM-5.ZSM-5 also inhibited the production of nitrogenous compounds.展开更多
To understand the catalytic conversion of lignin into high-value products,lignin depolymerization was performed using a layered polymetallic oxide(CuMgAlO_(x))catalyst.The effects of the conversion temperature,hydroge...To understand the catalytic conversion of lignin into high-value products,lignin depolymerization was performed using a layered polymetallic oxide(CuMgAlO_(x))catalyst.The effects of the conversion temperature,hydrogen pressure,and reaction time were studied,and the ability of CuMgAlO_(x)to break the C–O bond was evaluated.The CuMgAlO_(x)(Mg/Al=3:1)catalyst contained acidic sites and had a relatively homogeneous elemental distribution with a high pore size and specific surface area.Theβ-O-4 was almost completely converted by disassociating the C–O bond,resulting in yields of 14.74%ethylbenzene,47.58%α-methylphenyl ethanol,and 36.43%phenol.The highest yield of lignin-derived monophenols was 85.16%under reaction conditions of 280℃ and 3 Mpa for 4 h.As the reaction progressed,depolymerization and condensation reactions occurred simultaneously.Higher temperatures(>280℃)and pressures(>3 Mpa)tended to produce solid char.This study establishes guidelines for the high-value application of industrial lignin in the catalytic conversion of polymetallic oxides.展开更多
The regulation of the pyrolysis process is a key step in increasing the carbon sequestration capacity of biochar.The effect of K_(3)PO_(4)addition on the yield,chemical composition,characteristic functional groups,mac...The regulation of the pyrolysis process is a key step in increasing the carbon sequestration capacity of biochar.The effect of K_(3)PO_(4)addition on the yield,chemical composition,characteristic functional groups,macromolecular skeleton,graphite crystallites,and stability of biochar was studied in this paper using two-dimensional infrared correlation spectroscopy(2D-PCIS),X-ray photoelectron spectroscopy,Raman spectrum,and other characterization methods combined with thermal/chemical oxidation analysis.It is discovered that adding K_(3)PO_(4)may effectively minimize the graphitization temperature range and increase biochar’s yield,aromaticity,H/C ratio,and proportion of refractory/recalcitrant organic carbon.The 2D-PCIS and Raman analysis revealed that K_(3)PO_(4)mostly promoted the dehydrogenation and polycondensation process of the aromatic rings in the char precursor,transforming the amorphous carbon structure of biochar into an ordered turbostratic microcrystalline structure.K_(3)PO_(4)enhanced biochar stability mostly at medium-high temperatures(350~750℃)by stimulating the transformation of unstable structures of biochar to stable carbon-containing structures or by inhibiting the interaction of its active sites with oxidants through the mineralization process.A 20%phosphorus addition increased biochar’s refractory index(R_(50))by roughly 11%,and it also boosted biochar’s oxidation resistance(H_(2)O_(2)or K_(2)CrO_(4))efficiency,reducing carbon oxidation loss by up to 7.31%.However,at higher temperatures(>750℃),the doping of phosphorus atoms into the carbon skeleton degraded the biochar structure’s stability.The results of this study suggest that using exogenous phosphorus-containing additives is an efficient way to improve the stability of biochar.展开更多
As a low-value solid waste fuel,asphalt rock is prone to slagging even under fluidized bed condition.The purpose of this study is to improve the slagging characteristics of asphalt rock by adding the mineral additives...As a low-value solid waste fuel,asphalt rock is prone to slagging even under fluidized bed condition.The purpose of this study is to improve the slagging characteristics of asphalt rock by adding the mineral additives CaCO_(3),MgO,and Kaolin.The results showed that the K,Al,Ca salts in asphalt rock ash will evolve at different temperatures and exist mainly as K_(2)SO_(4),KAlSiO_(4),Al_(2)O_(3)·SiO_(2),Al_(2)O_(3),CaSO_(4),and CaSiO_(3).The CaSO_(4)formed from sulfur oxides and calcium-containing compounds is the main factor in asphalt rock slagging and can be facilitated by CaSiO_(3)with a small amount of CaCO_(3).The MgO can form MgCa(SiO_(3))_(2)with a high melting point and helps raise the ash fusion temperatures.In addition,the Kaolin will promote the formation of low-temperature eutectics,resulting in a slight decrease in ash fusion temperatures.Through optimization,it was found that with the addition of 9.0%MgO+9.0%Kaolin+2.0%CaCO_(3)(in weight),the slagging ratio and pressure difference of asphalt rock under fluidized bed conditions decreased from 6.5%to 4.2%and from 6.0 Pa to 4.0 Pa,respectively.By combining simulation and experimental methods,it has been shown that appropriate mineral additives of CaCO_(3),MgO,and Kaolin can effectively improve the slagging characteristics of asphalt rock.展开更多
Alkali metals(AMs)play an important role in biomass pyrolysis,and it is important to explore their catalytic effects so to better utilize biomass pyrolysis.This study analyzed the catalytic influence of K and Na with ...Alkali metals(AMs)play an important role in biomass pyrolysis,and it is important to explore their catalytic effects so to better utilize biomass pyrolysis.This study analyzed the catalytic influence of K and Na with different anions(Cl–,SO42–,and CO32–)on biomass pyrolysis,and explored the influence on the pyrolytic mechanism.AM chlorides(NaCl and KCl),sulfates(Na2SO4 and K2SO4)and carbonates(Na2CO3 and K2CO3)were mixed with cellulose and bamboo feedstocks at a mass ratio of 20 wt%,in order to maximize their potential on in situ upgrading of the pyrolysis products.AM chlorides had little effect on the pyrolysis products,whereas sulfates slightly promoted the yields of char and gas,and had a positive effect on the composition of the gaseous and liquid products.Carbonates noticeably increased the yields of the char and gases,and improved the C content of the char.Besides,AM salt catalysis is an effective method for co-production of bio-oil and porous char.展开更多
基金supported by the National Natural Science Foundation of China(52076099,52306257,and 72293601)。
文摘With extensive attention being paid to the potential environmental hazards of discarded face masks,catalytic pyrolysis technologies have been proposed to realize the valorization of wastes.However,recent catalyst selection and system design have focused solely on conversion efficiency,ignoring economic cost and potential life-cycle environmental damage.Here,we propose an economic-environmental hybrid pre-assessment method to help identify catalysts and reactors with less environmental impact and high economic returns among various routes to convert discarded face masks into carbon nanotubes(CNTs)and hydrogen.In catalyst selection,it was found that a widely known Fe-Ni catalyst exhibits higher catalytic activity than a cheaper Fe catalyst,potentially increasing the economic viability of the catalytic pyrolysis system by 38%-55%.The use of this catalyst also results in a carbon reduction of 4.12-10.20kilogram CO_(2) equivalent for 1 kilogram of discarded face masks,compared with the cheaper Fe catalyst.When the price of CNTs exceeds 1.49×10^(4) USD·t^(-1),microwave-assisted pyrolysis is the optimal choice due to its superior environmental performance(in terms of its life-cycle greenhouse gas reduction potential,eutrophication potential,and human toxicity)and economic benefits.In contrast,conventional heating pyrolysis may be a more economical option due to its good stability over 43 reaction regeneration cycles,as compared with a microwave-assisted pyrolysis catalyst with a higher conversion efficiency.This study connects foundational science with ecological economics to guide emerging technologies in their research stage toward technical efficiency,economic benefits,and environmental sustainability.
基金partially funded by the GTCLC-NEG project,which received funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement (101018756)the Brisk 2 European project (731101)for funding this project.The project acronym was B2PB-SIN2-1001,and the project title was“Optimization of catalytic pyrolysis of digestate and sewage sludge.”。
文摘Catalytic pyrolysis of digestate to produce aromatic hydrocarbons can be combined with anaerobic fermentation to effectively transform and utilize all biomass components,which can achieve the meaningful purpose of transforming waste into high-value products.This study explored whether catalytic pyrolysis of digestate is feasible to prepare aromatic hydrocarbons by analyzing the thermogravimetric characteristics,pyrolysis characteristics,and catalytic pyrolysis characteristics of digestate.For digestate pyrolysis,an increase in temperature was found to elevate the CO,CH_4,and monocyclic aromatic hydrocarbon(benzene,toluene,and xylene;BTX)content,whereas it decreased the contents of phenols,acids,aldehydes,and other oxygenates.Furthermore,the catalytic pyrolysis process effectively inhibited the acids,phenols,and furans in the liquid,whereas the yield of BTX increased from 25.45%to 45.99%,and the selectivity of xylene was also increased from 10.32%to 28.72%after adding ZSM-5.ZSM-5 also inhibited the production of nitrogenous compounds.
基金supported by the National Natural Science Fund for Distinguished Young Scholars(52125601).
文摘To understand the catalytic conversion of lignin into high-value products,lignin depolymerization was performed using a layered polymetallic oxide(CuMgAlO_(x))catalyst.The effects of the conversion temperature,hydrogen pressure,and reaction time were studied,and the ability of CuMgAlO_(x)to break the C–O bond was evaluated.The CuMgAlO_(x)(Mg/Al=3:1)catalyst contained acidic sites and had a relatively homogeneous elemental distribution with a high pore size and specific surface area.Theβ-O-4 was almost completely converted by disassociating the C–O bond,resulting in yields of 14.74%ethylbenzene,47.58%α-methylphenyl ethanol,and 36.43%phenol.The highest yield of lignin-derived monophenols was 85.16%under reaction conditions of 280℃ and 3 Mpa for 4 h.As the reaction progressed,depolymerization and condensation reactions occurred simultaneously.Higher temperatures(>280℃)and pressures(>3 Mpa)tended to produce solid char.This study establishes guidelines for the high-value application of industrial lignin in the catalytic conversion of polymetallic oxides.
基金funded by the National Natural Science Foundation of China(52306243,52125601)the China Postdoctoral Science Foundation(2023M731182).
文摘The regulation of the pyrolysis process is a key step in increasing the carbon sequestration capacity of biochar.The effect of K_(3)PO_(4)addition on the yield,chemical composition,characteristic functional groups,macromolecular skeleton,graphite crystallites,and stability of biochar was studied in this paper using two-dimensional infrared correlation spectroscopy(2D-PCIS),X-ray photoelectron spectroscopy,Raman spectrum,and other characterization methods combined with thermal/chemical oxidation analysis.It is discovered that adding K_(3)PO_(4)may effectively minimize the graphitization temperature range and increase biochar’s yield,aromaticity,H/C ratio,and proportion of refractory/recalcitrant organic carbon.The 2D-PCIS and Raman analysis revealed that K_(3)PO_(4)mostly promoted the dehydrogenation and polycondensation process of the aromatic rings in the char precursor,transforming the amorphous carbon structure of biochar into an ordered turbostratic microcrystalline structure.K_(3)PO_(4)enhanced biochar stability mostly at medium-high temperatures(350~750℃)by stimulating the transformation of unstable structures of biochar to stable carbon-containing structures or by inhibiting the interaction of its active sites with oxidants through the mineralization process.A 20%phosphorus addition increased biochar’s refractory index(R_(50))by roughly 11%,and it also boosted biochar’s oxidation resistance(H_(2)O_(2)or K_(2)CrO_(4))efficiency,reducing carbon oxidation loss by up to 7.31%.However,at higher temperatures(>750℃),the doping of phosphorus atoms into the carbon skeleton degraded the biochar structure’s stability.The results of this study suggest that using exogenous phosphorus-containing additives is an efficient way to improve the stability of biochar.
基金the Natural Science Foundation of China(Nos.52176187,51976075)the National Natural Science Funds for Distinguished Young Scholar(No.52125601).
文摘As a low-value solid waste fuel,asphalt rock is prone to slagging even under fluidized bed condition.The purpose of this study is to improve the slagging characteristics of asphalt rock by adding the mineral additives CaCO_(3),MgO,and Kaolin.The results showed that the K,Al,Ca salts in asphalt rock ash will evolve at different temperatures and exist mainly as K_(2)SO_(4),KAlSiO_(4),Al_(2)O_(3)·SiO_(2),Al_(2)O_(3),CaSO_(4),and CaSiO_(3).The CaSO_(4)formed from sulfur oxides and calcium-containing compounds is the main factor in asphalt rock slagging and can be facilitated by CaSiO_(3)with a small amount of CaCO_(3).The MgO can form MgCa(SiO_(3))_(2)with a high melting point and helps raise the ash fusion temperatures.In addition,the Kaolin will promote the formation of low-temperature eutectics,resulting in a slight decrease in ash fusion temperatures.Through optimization,it was found that with the addition of 9.0%MgO+9.0%Kaolin+2.0%CaCO_(3)(in weight),the slagging ratio and pressure difference of asphalt rock under fluidized bed conditions decreased from 6.5%to 4.2%and from 6.0 Pa to 4.0 Pa,respectively.By combining simulation and experimental methods,it has been shown that appropriate mineral additives of CaCO_(3),MgO,and Kaolin can effectively improve the slagging characteristics of asphalt rock.
基金The authors wish to express their great appreciation for the financial support received from the National Natural Science Foundation for Distinguished Young Scholars(Grant No.52125601)the National Natural Science Foundation of China(Grant No.52306244)。
文摘Alkali metals(AMs)play an important role in biomass pyrolysis,and it is important to explore their catalytic effects so to better utilize biomass pyrolysis.This study analyzed the catalytic influence of K and Na with different anions(Cl–,SO42–,and CO32–)on biomass pyrolysis,and explored the influence on the pyrolytic mechanism.AM chlorides(NaCl and KCl),sulfates(Na2SO4 and K2SO4)and carbonates(Na2CO3 and K2CO3)were mixed with cellulose and bamboo feedstocks at a mass ratio of 20 wt%,in order to maximize their potential on in situ upgrading of the pyrolysis products.AM chlorides had little effect on the pyrolysis products,whereas sulfates slightly promoted the yields of char and gas,and had a positive effect on the composition of the gaseous and liquid products.Carbonates noticeably increased the yields of the char and gases,and improved the C content of the char.Besides,AM salt catalysis is an effective method for co-production of bio-oil and porous char.
