The coal gangue as the only source of silicon and aluminum was employed to synthesize sodalite and faujasite using hydrothermal method,which directly treated the mixture of pre-treated coal gangue and NaOH solution un...The coal gangue as the only source of silicon and aluminum was employed to synthesize sodalite and faujasite using hydrothermal method,which directly treated the mixture of pre-treated coal gangue and NaOH solution under hydrothermal environment.X-ray powder diffraction analysis(XRD),thermogravimetry analysis(TG)and differential thermogravimetry analysis(DTG),scanning electron microscopy(SEM),high resolution transmission electron microscopy(HRTEM),N_(2)adsorption-desorption technique,X-ray photoelectron spectroscopy(XPS),etc.were used to characterize the samples.Cd^(2+) ion was used to evaluate the heavy metal ions removal performance of the samples.The experimental results show that the coal gangue,which consists of quartz,calcium feldspar,potassium feldspar and kaolinite,can transform to sodalite and faujasite under alkali-hydrothermal condition at 150 and 180℃,respectively.The as-prepared sodalite and faujasite can effectively remove the simulated Cd2+ion wastewater and actual industrial wastewater containing As^(3+),Cd^(2+),and Cr^(3+)ions,and the good heavy metal ion removal performance of the zeolites is mainly attributed to their low Si/Al ratio and high Na+content.This alkali-hydrothermal method appears to be a simple and efficient method for transformation of coal gangue to high purity zeolites.展开更多
Herein,we present a simple strategy for preparing monolithic sodalite adsorbents via sequential additive manufacturing and post-treatments.In detail,the method includes(i)3D printing of cylindrical monoliths using cla...Herein,we present a simple strategy for preparing monolithic sodalite adsorbents via sequential additive manufacturing and post-treatments.In detail,the method includes(i)3D printing of cylindrical monoliths using clay as the base material;(ii)thermal activation of the 3D-printed clay monoliths by calcination(to produce reactive alumina and silica species and enable mechanical stabilization);(iii)conversion of the activated clay monoliths to hierarchical porous sodalite monoliths via hydrothermal alkaline treatment.Parametric studies on the effect of calcination temperature,alkaline concentration and hydrothermal treatment time on the property of the resulting materials(such as phase composition and morphology)at different stages of preparation was conducted.Under the optimal conditions(i.e.,calcination temperature of 850℃,NaOH concentration of 3.3 mol·L^(-1),reaction temperature of 150℃,and reaction time of 6 h),a high-quality pure sodalite monolith was obtained,which possesses a relatively high BET surface area(58 m^(2)·g^(-1))and hierarchically micro-meso-macroporous structure.In the proposed application of continuous removal of heavy metals(chromium ion as the model)from wastewater,the developed 3D-printed sodalite monolith showed excellent Cr^(3+)removal performance and fast kinetics(~98%removal efficiency within 25 cycles),which outperformed the packed bed using sodalite pellets(made by extrusion).展开更多
Hydro-sodalites are zeolitic materials with a wide variety of applications.Fly ash is an abundant industrial solid waste,rich in silicon and aluminum,from which hydro-sodalite can be synthesized.However,traditional hy...Hydro-sodalites are zeolitic materials with a wide variety of applications.Fly ash is an abundant industrial solid waste,rich in silicon and aluminum,from which hydro-sodalite can be synthesized.However,traditional hydrothermal synthesis methods are complex and cannot produce high-purity products.Therefore,there is a demand for processing routes to obtain high-purity hydro-sodalites.In the present study,high-purity hydro-sodalite(90.2 wt%)was prepared from fly ash by applying a hydrothermal method to a submolten salt system.Samples were characterized by powder X-ray diffraction(XRD),scanning electron microscopy(SEM),thermogravimetry and differential thermal analysis(TG–DTA),and Fourier transform infrared spectroscopy(FTIR)to confirm and quantify conversion of the raw material into the product phase.Purity of the samples prepared with an H2O/Na OH mass ratio of 1.5 and an H2O/fly ash mass ratio of 10 was calculated and the conversion process of the product phase was studied.Crystallinity of the product was influenced more by the Na OH concentration,less by the H2O/fly ash mass ratio.The main reaction process of the system is that the Si O ions produced by dissolution of the vitreous body in the fly ash and Na+ions in the solution reacted on the destroyed mullite skeleton to produce hydro-sodalite.This processing route could help mitigate processing difficulties,while producing high-purity hydro-sodalite from fly ash.展开更多
Herein,we reported a method to prepare magnetic sodalite sphere by using the mud from backwash wastewater after polyaluminum chloride(PAC)coagulation.The results showed that approximately 100%of Fe in the wastewater w...Herein,we reported a method to prepare magnetic sodalite sphere by using the mud from backwash wastewater after polyaluminum chloride(PAC)coagulation.The results showed that approximately 100%of Fe in the wastewater was precipitated as flocculent iron mud(FM)by adding PAC.FM was converted to spherical magnetic sodalite(FMP)with a diameter of 3μm via a facile alkali hydrothermal method without adding Al/Si resources or reductant.The product FMP had the saturated magnetization of 10.9 emu g^(-1) and high Zn^(2+)adsorption capacity of 50.6 mg g^(-1).Without coagulation with PAC,the removal rate of Fe from the wastewater was only 92.7%,and the precipitated mud(RM)was converted to irregular particles(RMP),which had weak magnetic response and low capacity of Zn^(2+)adsorption comparing with FMP.With the method,the Fe in backwash wastewater was effectively recycled,and the generated sludge was converted to well-formed sodalite sphere without generating any secondary waste.展开更多
基金Founded by the Foundation of Shaanxi Province Key Provence Research and Development(No.2022GY-163)the Foundation of Xianyang City Key Research and Development(No.2021ZDYFGY-0038)+1 种基金the Foundation of Shaanxi Provincial Education Department(No.22JC020)the Key Laboratory of Sustained Utilization&Development of Water Recourse of Hebei Province(Hebei Geo University)(No.HSZYL2021002)。
文摘The coal gangue as the only source of silicon and aluminum was employed to synthesize sodalite and faujasite using hydrothermal method,which directly treated the mixture of pre-treated coal gangue and NaOH solution under hydrothermal environment.X-ray powder diffraction analysis(XRD),thermogravimetry analysis(TG)and differential thermogravimetry analysis(DTG),scanning electron microscopy(SEM),high resolution transmission electron microscopy(HRTEM),N_(2)adsorption-desorption technique,X-ray photoelectron spectroscopy(XPS),etc.were used to characterize the samples.Cd^(2+) ion was used to evaluate the heavy metal ions removal performance of the samples.The experimental results show that the coal gangue,which consists of quartz,calcium feldspar,potassium feldspar and kaolinite,can transform to sodalite and faujasite under alkali-hydrothermal condition at 150 and 180℃,respectively.The as-prepared sodalite and faujasite can effectively remove the simulated Cd2+ion wastewater and actual industrial wastewater containing As^(3+),Cd^(2+),and Cr^(3+)ions,and the good heavy metal ion removal performance of the zeolites is mainly attributed to their low Si/Al ratio and high Na+content.This alkali-hydrothermal method appears to be a simple and efficient method for transformation of coal gangue to high purity zeolites.
基金the Key Project on Intergovernmental International Science, Technology and Innovation (STI) Cooperation/STI Cooperation with Hong Kong, MacaoTaiwan of China’s National Key Research & Development Programme (2019YFE0123200)+1 种基金the National Natural Science Foundation of China (22078348)funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement (No. 872102)
文摘Herein,we present a simple strategy for preparing monolithic sodalite adsorbents via sequential additive manufacturing and post-treatments.In detail,the method includes(i)3D printing of cylindrical monoliths using clay as the base material;(ii)thermal activation of the 3D-printed clay monoliths by calcination(to produce reactive alumina and silica species and enable mechanical stabilization);(iii)conversion of the activated clay monoliths to hierarchical porous sodalite monoliths via hydrothermal alkaline treatment.Parametric studies on the effect of calcination temperature,alkaline concentration and hydrothermal treatment time on the property of the resulting materials(such as phase composition and morphology)at different stages of preparation was conducted.Under the optimal conditions(i.e.,calcination temperature of 850℃,NaOH concentration of 3.3 mol·L^(-1),reaction temperature of 150℃,and reaction time of 6 h),a high-quality pure sodalite monolith was obtained,which possesses a relatively high BET surface area(58 m^(2)·g^(-1))and hierarchically micro-meso-macroporous structure.In the proposed application of continuous removal of heavy metals(chromium ion as the model)from wastewater,the developed 3D-printed sodalite monolith showed excellent Cr^(3+)removal performance and fast kinetics(~98%removal efficiency within 25 cycles),which outperformed the packed bed using sodalite pellets(made by extrusion).
基金financially supported by the National Natural Science Foundation of China (No. 51474028)the National Key Research and Development Program of China (No. 2017YFC0210301)+1 种基金China Postdoctoral Science Foundation (No. 2017M621034)the Science and Technology Benefiting Citizens Program of Ningbo, China (No. 2015C50058)
文摘Hydro-sodalites are zeolitic materials with a wide variety of applications.Fly ash is an abundant industrial solid waste,rich in silicon and aluminum,from which hydro-sodalite can be synthesized.However,traditional hydrothermal synthesis methods are complex and cannot produce high-purity products.Therefore,there is a demand for processing routes to obtain high-purity hydro-sodalites.In the present study,high-purity hydro-sodalite(90.2 wt%)was prepared from fly ash by applying a hydrothermal method to a submolten salt system.Samples were characterized by powder X-ray diffraction(XRD),scanning electron microscopy(SEM),thermogravimetry and differential thermal analysis(TG–DTA),and Fourier transform infrared spectroscopy(FTIR)to confirm and quantify conversion of the raw material into the product phase.Purity of the samples prepared with an H2O/Na OH mass ratio of 1.5 and an H2O/fly ash mass ratio of 10 was calculated and the conversion process of the product phase was studied.Crystallinity of the product was influenced more by the Na OH concentration,less by the H2O/fly ash mass ratio.The main reaction process of the system is that the Si O ions produced by dissolution of the vitreous body in the fly ash and Na+ions in the solution reacted on the destroyed mullite skeleton to produce hydro-sodalite.This processing route could help mitigate processing difficulties,while producing high-purity hydro-sodalite from fly ash.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2019YFE0117900)the National Natural Science Foundation of China(Grant Nos.52070038 and 51878134)the Science and Technology Program of Jilin Province(Grant No.20190303001SF).
文摘Herein,we reported a method to prepare magnetic sodalite sphere by using the mud from backwash wastewater after polyaluminum chloride(PAC)coagulation.The results showed that approximately 100%of Fe in the wastewater was precipitated as flocculent iron mud(FM)by adding PAC.FM was converted to spherical magnetic sodalite(FMP)with a diameter of 3μm via a facile alkali hydrothermal method without adding Al/Si resources or reductant.The product FMP had the saturated magnetization of 10.9 emu g^(-1) and high Zn^(2+)adsorption capacity of 50.6 mg g^(-1).Without coagulation with PAC,the removal rate of Fe from the wastewater was only 92.7%,and the precipitated mud(RM)was converted to irregular particles(RMP),which had weak magnetic response and low capacity of Zn^(2+)adsorption comparing with FMP.With the method,the Fe in backwash wastewater was effectively recycled,and the generated sludge was converted to well-formed sodalite sphere without generating any secondary waste.
