The production of titanium dioxide(a necessary industrial color additive)can generate massive amount of titanium gypsum,a hard-to-treat solid waste.Diverse metallic impurities,heavy metals and reddish color in titaniu...The production of titanium dioxide(a necessary industrial color additive)can generate massive amount of titanium gypsum,a hard-to-treat solid waste.Diverse metallic impurities,heavy metals and reddish color in titanium gypsum make it difficult to be used in building materials like other by-product gypsums.As a result,most of titanium gypsum in China is just stored and has caused serious environmental issues.In this study,titanium gypsum,which contained high contents of impurities and heavy metals,was synergistically used with other three solid wastes to prepare sulfoaluminate cementitious material(SACM)for the first time.The mass proportion of titanium gypsum in the raw materials exceeded 25%.The chemical,mechanical and heavy metal leaching characteristics of this solid waste-based SACM were tested via XRD,XRF,ICP-OES,etc.The main components and metallic impurities of titanium gypsum could be transformed to the components of the main mineral of SACM,ye’elimite.The compressive strength of the prepared SACM reached 38.2,59.7 and 95.8 MPa at 1-day,3-day,and 28-day hydration,respectively,indicating the features of rapidly hardening and high strength.Importantly,the solid waste-based SACM could effectively solidify the heavy metals contained in titanium gypsum and other raw material during thje hydration process.The retention ratio of total Cr reached 97.5%,and other heavy metals were almost not detected in the leachate of SACM.This study provided a feasible approach to utilize titanium gypsum to produce high-performance,green building material,and might promote the massive utilization of this solid waste.展开更多
Filtering capacitor with compact configuration and a wide range of operating voltage has been attracting increasing attention for the smooth conversion of the electric signal in modern circuits.Lossless integration of...Filtering capacitor with compact configuration and a wide range of operating voltage has been attracting increasing attention for the smooth conversion of the electric signal in modern circuits.Lossless integration of capacitor units can be regarded as one of the efficient ways to achieve a wider voltage range,which has not yet been fully conquered due to the lack of rational designs of the electrode structure and integration technology.This study presents an alternatingly stacked assemble technology to conveniently fabricate compact aqueous hybrid integrated filtering capacitors on a large scale,in which a unit consists of rGO/MXene composite film as a negative electrode and PEDOT:PSS based film as a positive electrode.Benefiting from the synergistic effect of rGO and MXene components,and morphological characteristics of PEDOT:PSS,the capacitor unit exhibits outstanding AC line filtering with a large areal specific energy density of 1,015 μF V^(2)cm^(-2)(0.28 μW h cm^(-2)) at 120 Hz.After rational integration,the assembled capacitors present compact/lightweight configuration and lossless frequency response,as reflected by almost constant resistor-capacitor time constant of 0.2 ms and dissipation factor of 15% at120 Hz,identical to those of the single capacitor unit.Apart from standing alone steadily on a flower,a small volume(only 8.1 cm^(3)) of the integrated capacitor with 70 units connected in series achieves hundred-volts alternating current line filtering,which is superior to most reported filtering capacitors with sandwich configuration.This study provides insight into the fabrication and application of compact/ultralight filtering capacitors with lossless frequency response,and a wide range of operating voltage.展开更多
基金funded by the National Key Research&Development Program of China(No.2017YFC0703100).
文摘The production of titanium dioxide(a necessary industrial color additive)can generate massive amount of titanium gypsum,a hard-to-treat solid waste.Diverse metallic impurities,heavy metals and reddish color in titanium gypsum make it difficult to be used in building materials like other by-product gypsums.As a result,most of titanium gypsum in China is just stored and has caused serious environmental issues.In this study,titanium gypsum,which contained high contents of impurities and heavy metals,was synergistically used with other three solid wastes to prepare sulfoaluminate cementitious material(SACM)for the first time.The mass proportion of titanium gypsum in the raw materials exceeded 25%.The chemical,mechanical and heavy metal leaching characteristics of this solid waste-based SACM were tested via XRD,XRF,ICP-OES,etc.The main components and metallic impurities of titanium gypsum could be transformed to the components of the main mineral of SACM,ye’elimite.The compressive strength of the prepared SACM reached 38.2,59.7 and 95.8 MPa at 1-day,3-day,and 28-day hydration,respectively,indicating the features of rapidly hardening and high strength.Importantly,the solid waste-based SACM could effectively solidify the heavy metals contained in titanium gypsum and other raw material during thje hydration process.The retention ratio of total Cr reached 97.5%,and other heavy metals were almost not detected in the leachate of SACM.This study provided a feasible approach to utilize titanium gypsum to produce high-performance,green building material,and might promote the massive utilization of this solid waste.
基金supported by the NSFC(21805072,22075019,22035005)the National Key R&D Program of China(2017YFB1104300)。
文摘Filtering capacitor with compact configuration and a wide range of operating voltage has been attracting increasing attention for the smooth conversion of the electric signal in modern circuits.Lossless integration of capacitor units can be regarded as one of the efficient ways to achieve a wider voltage range,which has not yet been fully conquered due to the lack of rational designs of the electrode structure and integration technology.This study presents an alternatingly stacked assemble technology to conveniently fabricate compact aqueous hybrid integrated filtering capacitors on a large scale,in which a unit consists of rGO/MXene composite film as a negative electrode and PEDOT:PSS based film as a positive electrode.Benefiting from the synergistic effect of rGO and MXene components,and morphological characteristics of PEDOT:PSS,the capacitor unit exhibits outstanding AC line filtering with a large areal specific energy density of 1,015 μF V^(2)cm^(-2)(0.28 μW h cm^(-2)) at 120 Hz.After rational integration,the assembled capacitors present compact/lightweight configuration and lossless frequency response,as reflected by almost constant resistor-capacitor time constant of 0.2 ms and dissipation factor of 15% at120 Hz,identical to those of the single capacitor unit.Apart from standing alone steadily on a flower,a small volume(only 8.1 cm^(3)) of the integrated capacitor with 70 units connected in series achieves hundred-volts alternating current line filtering,which is superior to most reported filtering capacitors with sandwich configuration.This study provides insight into the fabrication and application of compact/ultralight filtering capacitors with lossless frequency response,and a wide range of operating voltage.
