Microbe cement,a new type of gelling material,has attracted wide attention due to the increasing awareness of environmental protection.In this paper,the microbe cement in solidifying municipal solid waste incineration...Microbe cement,a new type of gelling material,has attracted wide attention due to the increasing awareness of environmental protection.In this paper,the microbe cement in solidifying municipal solid waste incineration(MSWI)fly ash is investigated and the effect of the microbial induction method in solidifying MSWI fly ash is compared with the traditional chemical reaction strategy by characterizing the resulted calcite and the solidification productions with electronic universal testing machine,X-ray diffractometer(XRD),Fourier transform infrared spectrometer(FTIR),scanning electron microscope(SEM)and atomic absorption spectrometer.The results show that the MSWI fly ash solidified by microbe cement has the highest compressive strength while that of the chemical CaCO3 products is the lowest.The XRD results show that a new hydration gelling substance(Ca2SiO4·0.30H2O)is generated in the MSWI fly ash products.The FTIR results show that the frequency of Si-O bonds and C-O bonds in the products solidified by microbe cement has shifted,while there is no change occurred in the chemical CaCO3 products.The SEM results show that the microstructure of the products solidified by microbe cement is denser than that of chemical CaCO3 products.The test results of heavy metals show that the microbe cement could reduce the leaching concentration of heavy metals in MSWI fly ash.Ultimately,the leaching concentration of Pb meets the standard requirements,while that of Cd is still slightly higher than the standard requirement.展开更多
Researches on the hydrothermal treatment of municipal solid waste incineration(MSWI)fly ash were conducted to eliminate dioxins and stabilize heavy metals.In order to enhance decomposing polychlorinated dibenzodioxins...Researches on the hydrothermal treatment of municipal solid waste incineration(MSWI)fly ash were conducted to eliminate dioxins and stabilize heavy metals.In order to enhance decomposing polychlorinated dibenzodioxins(PCDDs)and polychlorinated dibenzo-furans(PCDFs)during hydrothermal process,a strong reductant carbohydrazide(CHZ)is introduced.A hydrothermal reactor was set up by mixing raw MSWI fly ash or the pre-treated fly ash with water and then heated to a pre-set temperature;CHZ was spiked into solution according to specially defined dosage.Experimental results showed that under the temperatures of 518 K and 533 K,the decomposition rates of PCDDs/PCDFs were over 80%and 90%,respectively,by total concentration.However,their toxic equivalent(TEQ)decreased only slightly or even increased due to the rising in concentration of congeners 2,3,7,8-TCDD/TCDF,which might be resulted from the highly chlorinated congeners losing their chlorine atoms and being degraded during the hydrothermal process.Better results of TEQ reduction were also obtained under the higher tested temperature of 533 K and reactor with addition of 0.1%wt CHZ was corresponded to the best results.Good stabilization of heavy metals was also obtained in the same hydrothermal process especially when ferrous sulphate was added as auxiliary agent.展开更多
Municipal solid waste incinerated(MSWI) fly ash contains heavy metals and chloride,which is urgent to be disposed via an effective method.Herein,glass-ceramics,one of the recycling waste materials based on MSWI fly as...Municipal solid waste incinerated(MSWI) fly ash contains heavy metals and chloride,which is urgent to be disposed via an effective method.Herein,glass-ceramics,one of the recycling waste materials based on MSWI fly ash with high chloride content,have been developed from one-step process.MSWI fly ash and waste glass have been utilized as calcium and silicon sources,respectively.Glass-ceramics were successfully prepared by the one-step process.It is found that the increase in MSWI fly ash promotes the fracture of glass mesh(Si-O)and the generation of non-bridging oxygen,reducing the polymerization degree of glass network structure,which leads to the decrease in glass stability.The difference between glass transition temperature(T_(g)) and crystallization temperature(T_(c)) was narrowed,and crystallization activation energy of basic glass was reduced,which promoted crystallization.With lower crystallization activation energy(E=217.56 kJ·mol^(-1)) and high utilization rate of 50 wt% MSWI fly ash,the optimal glass-ceramics with spherical diopside,cuspidine and glass phase,excellent hardness of 7.97 GPa and bending resistance of 114.86 MPa are achieved.It is worth mentioning that most of the high content of chlorine in MSWI fly ash will evaporate during vitrification process;the residual chlorine as well as heavy metals can be present steadily in crystalline grains.Therefore,this study not only increases the attachment value of MSWI fly ash,but also eliminates the problems caused by high chlorine and heavy metals in MSWI fly ash.展开更多
基金the National Nature Science Foundation of China(Nos.51978439 and 51708390)the Tianjin Transport Technology Development Project(No.2018-38)+1 种基金the Project Funded by China Postdoctoral Science Foundation(No.2019M651000)the Tianjin Rail Transit Major Special Project(No.18ZXGDGX00050)。
文摘Microbe cement,a new type of gelling material,has attracted wide attention due to the increasing awareness of environmental protection.In this paper,the microbe cement in solidifying municipal solid waste incineration(MSWI)fly ash is investigated and the effect of the microbial induction method in solidifying MSWI fly ash is compared with the traditional chemical reaction strategy by characterizing the resulted calcite and the solidification productions with electronic universal testing machine,X-ray diffractometer(XRD),Fourier transform infrared spectrometer(FTIR),scanning electron microscope(SEM)and atomic absorption spectrometer.The results show that the MSWI fly ash solidified by microbe cement has the highest compressive strength while that of the chemical CaCO3 products is the lowest.The XRD results show that a new hydration gelling substance(Ca2SiO4·0.30H2O)is generated in the MSWI fly ash products.The FTIR results show that the frequency of Si-O bonds and C-O bonds in the products solidified by microbe cement has shifted,while there is no change occurred in the chemical CaCO3 products.The SEM results show that the microstructure of the products solidified by microbe cement is denser than that of chemical CaCO3 products.The test results of heavy metals show that the microbe cement could reduce the leaching concentration of heavy metals in MSWI fly ash.Ultimately,the leaching concentration of Pb meets the standard requirements,while that of Cd is still slightly higher than the standard requirement.
基金the National High-Tech Research and Development(863)Program of China(Grant No.2008AA06Z340)the National Natural Science Foundation of China(Grant No.50708068).
文摘Researches on the hydrothermal treatment of municipal solid waste incineration(MSWI)fly ash were conducted to eliminate dioxins and stabilize heavy metals.In order to enhance decomposing polychlorinated dibenzodioxins(PCDDs)and polychlorinated dibenzo-furans(PCDFs)during hydrothermal process,a strong reductant carbohydrazide(CHZ)is introduced.A hydrothermal reactor was set up by mixing raw MSWI fly ash or the pre-treated fly ash with water and then heated to a pre-set temperature;CHZ was spiked into solution according to specially defined dosage.Experimental results showed that under the temperatures of 518 K and 533 K,the decomposition rates of PCDDs/PCDFs were over 80%and 90%,respectively,by total concentration.However,their toxic equivalent(TEQ)decreased only slightly or even increased due to the rising in concentration of congeners 2,3,7,8-TCDD/TCDF,which might be resulted from the highly chlorinated congeners losing their chlorine atoms and being degraded during the hydrothermal process.Better results of TEQ reduction were also obtained under the higher tested temperature of 533 K and reactor with addition of 0.1%wt CHZ was corresponded to the best results.Good stabilization of heavy metals was also obtained in the same hydrothermal process especially when ferrous sulphate was added as auxiliary agent.
基金financially supported by the National Key R&D Projects(Nos.2019YFC1907101,2019YFC1907103 and 2017YFB0702304)Key R&D Project in Ningxia Hui Autonomous Region(No.2020BCE01001)+4 种基金the National Natural Science Foundation of China(No.51672024)Xinjiang Innovation and Entrepreneurship Team(No.2017A0109004)the Fundamental Research Funds for the Central Universities(Nos.FRFIC-19-007,FRF-IC-19-017Z,FRF-MP-19-002,FRF-TP-19-003B1,FRF-GF-19-032B and 06500141)the State Key Laboratory for Advanced Metals and Materials(No.2019Z-05)Integration of Green Key Process Systems MIIT。
文摘Municipal solid waste incinerated(MSWI) fly ash contains heavy metals and chloride,which is urgent to be disposed via an effective method.Herein,glass-ceramics,one of the recycling waste materials based on MSWI fly ash with high chloride content,have been developed from one-step process.MSWI fly ash and waste glass have been utilized as calcium and silicon sources,respectively.Glass-ceramics were successfully prepared by the one-step process.It is found that the increase in MSWI fly ash promotes the fracture of glass mesh(Si-O)and the generation of non-bridging oxygen,reducing the polymerization degree of glass network structure,which leads to the decrease in glass stability.The difference between glass transition temperature(T_(g)) and crystallization temperature(T_(c)) was narrowed,and crystallization activation energy of basic glass was reduced,which promoted crystallization.With lower crystallization activation energy(E=217.56 kJ·mol^(-1)) and high utilization rate of 50 wt% MSWI fly ash,the optimal glass-ceramics with spherical diopside,cuspidine and glass phase,excellent hardness of 7.97 GPa and bending resistance of 114.86 MPa are achieved.It is worth mentioning that most of the high content of chlorine in MSWI fly ash will evaporate during vitrification process;the residual chlorine as well as heavy metals can be present steadily in crystalline grains.Therefore,this study not only increases the attachment value of MSWI fly ash,but also eliminates the problems caused by high chlorine and heavy metals in MSWI fly ash.
