Lime mud is a kind of solid waste in the papermaking industry,which has been a source of serious environmental pollution.Ceramsites containing anorthite and gehlenite were prepared from lime mud and fly ash through th...Lime mud is a kind of solid waste in the papermaking industry,which has been a source of serious environmental pollution.Ceramsites containing anorthite and gehlenite were prepared from lime mud and fly ash through the solid state reaction method at 1050°C.The objective of this study was to explore the efficiency of Ca^2＋ and OH-release and assess the phosphorus and copper ion removal performance of the ceramsites via batch experiments,X-ray diffraction（XRD） and scanning electron microscopy（SEM）.The results show that Ca^2＋ and OH-were released from the ceramsites due to the dissolution of anorthite,gehlenite and available lime.It is also concluded that gehlenite had stronger capacity for Ca^2＋ and OH-release compared with anorthite.The Ca^2＋ release could be fit well by the Avrami kinetic model.Increases of porosity,dosage and temperature were associated with increases in the concentrations of Ca^2＋ and OH-released.Under different conditions,the ceramsites could maintain aqueous solutions in alkaline conditions（p H = 9.3–10.9） and the release of Ca^2＋ was not affected.The removal rates of phosphorus and copper ions were as high as 96.88% and 96.81%,respectively.The final p H values of both phosphorus and copper ions solutions changed slightly.The reuse of lime mud in the form of ceramsites is an effective strategy.展开更多
Material conversion from paper sludge ash （PSA） in NaOH solution was attempted to synthesize the adsorbent for removal of inorganic pollutants, such as Pb^2＋, NH^4＋ and PO4^3- from aqueous solution. PSA of 0.5 g w...Material conversion from paper sludge ash （PSA） in NaOH solution was attempted to synthesize the adsorbent for removal of inorganic pollutants, such as Pb^2＋, NH^4＋ and PO4^3- from aqueous solution. PSA of 0.5 g was added into 10 mL of 3 mol/L NaOH solution, and then heated at 80, 120, and 160℃ for 6-48 hr to obtain the product. PSA mainly composed of two crystalline phases, gehlenite （Ca2Al2SiO7） and anorthite （CaAl2Si2O8）, and amorphous phase. Hydroxysodalite （Na6Al6Si6O24-8H2O） was formed at 80℃, and anorthite dissolved, whereas gehlenite remained unaffected. Katoite （Ca3Al2SiO4（OH）8） was formed over 120℃, and hydroxycancrinite （Nas（OH）2Al6Si6O24·2H2O） was formed at 160℃, due to the dissolution of both gehlenite and anorthite. Specific surface areas of the products were almost same and were higher than that of raw ash. Cation exchange capacities （CECs） of the products were also higher than that of raw ash, and CEC obtained at lower temperature was higher. Removal abilities of products for Pb^2＋, NH4＋, and PO4^3- were higher than that of raw ash. With increasing reaction temperature, the removal efficiencies of Pb^2＋ and NH4＋ decreased due to the decrease of CEC of the product, while removal efficiency for PO4^3- was almost same. The concentrations of Si and AI in the solution and the crystalline phases in the solid during the reaction explain the formation of the product phases at each temperature.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.51578289 and 51468053)the Technology Major Projects of China (No.2012ZX04010-032)+1 种基金the Research and innovation program of graduate students in Jiangsu Province (No.KYLX_0347)the Innovation Fund for National Small and Medium Technology Based Firms of China (No.11C26213201410)
文摘Lime mud is a kind of solid waste in the papermaking industry,which has been a source of serious environmental pollution.Ceramsites containing anorthite and gehlenite were prepared from lime mud and fly ash through the solid state reaction method at 1050°C.The objective of this study was to explore the efficiency of Ca^2＋ and OH-release and assess the phosphorus and copper ion removal performance of the ceramsites via batch experiments,X-ray diffraction（XRD） and scanning electron microscopy（SEM）.The results show that Ca^2＋ and OH-were released from the ceramsites due to the dissolution of anorthite,gehlenite and available lime.It is also concluded that gehlenite had stronger capacity for Ca^2＋ and OH-release compared with anorthite.The Ca^2＋ release could be fit well by the Avrami kinetic model.Increases of porosity,dosage and temperature were associated with increases in the concentrations of Ca^2＋ and OH-released.Under different conditions,the ceramsites could maintain aqueous solutions in alkaline conditions（p H = 9.3–10.9） and the release of Ca^2＋ was not affected.The removal rates of phosphorus and copper ions were as high as 96.88% and 96.81%,respectively.The final p H values of both phosphorus and copper ions solutions changed slightly.The reuse of lime mud in the form of ceramsites is an effective strategy.
基金supported by the Mukai Science and Technology Foundation and the Intelligent Cosmos Academic Foundation
文摘Material conversion from paper sludge ash （PSA） in NaOH solution was attempted to synthesize the adsorbent for removal of inorganic pollutants, such as Pb^2＋, NH^4＋ and PO4^3- from aqueous solution. PSA of 0.5 g was added into 10 mL of 3 mol/L NaOH solution, and then heated at 80, 120, and 160℃ for 6-48 hr to obtain the product. PSA mainly composed of two crystalline phases, gehlenite （Ca2Al2SiO7） and anorthite （CaAl2Si2O8）, and amorphous phase. Hydroxysodalite （Na6Al6Si6O24-8H2O） was formed at 80℃, and anorthite dissolved, whereas gehlenite remained unaffected. Katoite （Ca3Al2SiO4（OH）8） was formed over 120℃, and hydroxycancrinite （Nas（OH）2Al6Si6O24·2H2O） was formed at 160℃, due to the dissolution of both gehlenite and anorthite. Specific surface areas of the products were almost same and were higher than that of raw ash. Cation exchange capacities （CECs） of the products were also higher than that of raw ash, and CEC obtained at lower temperature was higher. Removal abilities of products for Pb^2＋, NH4＋, and PO4^3- were higher than that of raw ash. With increasing reaction temperature, the removal efficiencies of Pb^2＋ and NH4＋ decreased due to the decrease of CEC of the product, while removal efficiency for PO4^3- was almost same. The concentrations of Si and AI in the solution and the crystalline phases in the solid during the reaction explain the formation of the product phases at each temperature.
