Na-A zeolite was synthesized using oil shale ash （OSA）, which is a solid by-product of oil shale proc- essing. The samples were characterized by various techniques, such as scanning electron microscopy, X-ray diffra...Na-A zeolite was synthesized using oil shale ash （OSA）, which is a solid by-product of oil shale proc- essing. The samples were characterized by various techniques, such as scanning electron microscopy, X-ray diffrac- tion and Brunaner Emmet Teller method. The batch isothermal equilibrium adsorption experiments were performed to evaluate the ability of Na-A zeolite for removal of Cu （II） from aqueous solutions. The effects of operating pa- rameters, such as concentration of copper solutions, adsorbent dosages, pH value of solutions and temperature, on the adsorption efficiency were investigated. The equilibrium adsorption data were fitted with Langmuir and Freundlich models. The maximum adsorption capacity of Na-A zeolite obtained from the Langmuir adsorption iso- therm is 156.7 mg.g-t of Cu （lI）. The increase of pH level in the adsorption process suggests that the uptake of heavy metals on the zeolite follows an ion exchange mechanism. The batch kinetic data fit the pseudo-second order equation well. The thermodynamic parameters, such as changes in Gibbs free energy （AG）, enthalpy （AH） and en- tropy （AS）, are used to predict the nature of the adsorption process. The negative AG values at different tempera- tures confirm that the adsorption processes are spontaneous.展开更多
A single phrase Na - X zeolite was synthesized from pretreated oil shale ash by alkaline fusion and hydrotherreal treatment. Eff3cts of the NaOH concentration, crystallization time ant temperature on the formation of ...A single phrase Na - X zeolite was synthesized from pretreated oil shale ash by alkaline fusion and hydrotherreal treatment. Eff3cts of the NaOH concentration, crystallization time ant temperature on the formation of Na-X zeolite were studied in detail. The single phase Na- X zeolite powders can. be prepared by alkaline fusion o.f pretreated oil shale ash at 600 ℃ .for 1 h, and crystalli-zation at 80 - 100 ℃ .for 8 - 10 h with NaOH concentration of 3 -3. 5 tool · L-1. Na - A zeolite appears when decreasing NaOH concentration, crystallization time or temperature, ant an unnamed zeolite emerges when prolonging crystallization time or raising crystalli-zation, temperature. SEM micrographs suggest that the aggregates of Na-X zeolite particles have perfect dispersity and uniform granular with about 1.5 μm in size, and most of the Na-X zeolite crystals display a regular octahedral structure with the size of about 500 nm. The specific surface area of the powders with single Na-X zeolite phase reaches the maximum value of 488. 163 2 m2· g -1, larger than that of multiple zeolite powders.展开更多
The microstructure and the mechanical properties of hardened mortars made of superplasticized composite binder containing shale ash and fly ash are investigated. The pozzolanic reaction consumes the oriented Ca (OH)/...The microstructure and the mechanical properties of hardened mortars made of superplasticized composite binder containing shale ash and fly ash are investigated. The pozzolanic reaction consumes the oriented Ca (OH)//2 crystals, thus making the transition zone dense. Appropriately proportioning of shale ash and fly ash decreases the water requirement and increases the packing density of composite binder mortars, therefore increases their strength. Superplasticizer promotes the carbonation of calcium hydrates and the formation of ettringite that is transformed gradually into mono-sulfoaluminate hydrate in composite binder mortars. The joint action of fine complex mineral admixture and superplasticizer has a synergistic effect to improve the mechanical properties of composite binder. (Author abstract) 7 Refs.展开更多
This paper presents the first study on the oil shale (OS) ashing and OS ash leachability of Jordanian OS located further in the south. The studied OS is from Isfir Al-Mahata subsurface OS located 10 km south of Ma’an...This paper presents the first study on the oil shale (OS) ashing and OS ash leachability of Jordanian OS located further in the south. The studied OS is from Isfir Al-Mahata subsurface OS located 10 km south of Ma’an. Chemical and physical characterization of the OS ash was performed and compared with original OS. Ashing OS was conducted at different temperatures. Important parameters affecting OS ash leachability were also investigated. The leachability of certain heavy metals was investigated based on clear leaching protocol. The Fisher Assay analysis result indicates that this OS type has quite higher moisture content, lower oil content, and higher spent shale compared with other Jordanian oil shales. Ashing of OS at higher temperatures (950°C) resulted in the disappearance of silica, due to its complete reaction with lime and Al, and formation of Anhydrite and cement materials like, Portland cement. The leachability analysis indicates that for most elements the leachability is high at low pH. The released heavy metals concentrations are below EPA limits. Chromium and lead are leached out more than other elements with the exception at low pH. In general, the higher the ashing temperature is, the lower the release of elements is. The chemical composition of the ash and the leachability results suggests that it has high fixing capacity toward the heavy metals present in the ash.展开更多
Na-X zeolites were synthesized by Longkou oil shale ash with the alkaline fusion hydrothermal method.The effects of fusion temperature,ash to NaOH ratio,solid-liquid ratio,crystallization time and crystallization temp...Na-X zeolites were synthesized by Longkou oil shale ash with the alkaline fusion hydrothermal method.The effects of fusion temperature,ash to NaOH ratio,solid-liquid ratio,crystallization time and crystallization temperature on the crystallinity of zeolites were investigated.The synthetic products were characterized by Xray diffraction(XRD),scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),29Si nuclear magnetic resonance spectroscopy(29Si NMR)and N2 adsorption-desorption.The results showed that the conditions to synthesize Na-X zeolite were:Longkou oil shale ash to sodium hydroxide ratio 1:1.2 g・g^(-1),fusion temperature 600℃,solid-liquid ratio 1:4 g・mL^(-1),crystallization time 24 h and crystallization temperature 80℃.The zeolite with high crystallinity(91.32%)was synthesized:the product exhibiting octahedral particles observed by SEM,and the calculated Si/Al ratio in Na-X zeolite being 1.23 from^(29)Si MAS NMR spectra,which was consistent with the observation from XRD.展开更多
基金Supported by the National Innovative Projects with Cooperation in terms of Production,Study and Research(OSR-05)the National Science and Technology Major Projects(2008ZX05018-005)
文摘Na-A zeolite was synthesized using oil shale ash （OSA）, which is a solid by-product of oil shale proc- essing. The samples were characterized by various techniques, such as scanning electron microscopy, X-ray diffrac- tion and Brunaner Emmet Teller method. The batch isothermal equilibrium adsorption experiments were performed to evaluate the ability of Na-A zeolite for removal of Cu （II） from aqueous solutions. The effects of operating pa- rameters, such as concentration of copper solutions, adsorbent dosages, pH value of solutions and temperature, on the adsorption efficiency were investigated. The equilibrium adsorption data were fitted with Langmuir and Freundlich models. The maximum adsorption capacity of Na-A zeolite obtained from the Langmuir adsorption iso- therm is 156.7 mg.g-t of Cu （lI）. The increase of pH level in the adsorption process suggests that the uptake of heavy metals on the zeolite follows an ion exchange mechanism. The batch kinetic data fit the pseudo-second order equation well. The thermodynamic parameters, such as changes in Gibbs free energy （AG）, enthalpy （AH） and en- tropy （AS）, are used to predict the nature of the adsorption process. The negative AG values at different tempera- tures confirm that the adsorption processes are spontaneous.
文摘A single phrase Na - X zeolite was synthesized from pretreated oil shale ash by alkaline fusion and hydrotherreal treatment. Eff3cts of the NaOH concentration, crystallization time ant temperature on the formation of Na-X zeolite were studied in detail. The single phase Na- X zeolite powders can. be prepared by alkaline fusion o.f pretreated oil shale ash at 600 ℃ .for 1 h, and crystalli-zation at 80 - 100 ℃ .for 8 - 10 h with NaOH concentration of 3 -3. 5 tool · L-1. Na - A zeolite appears when decreasing NaOH concentration, crystallization time or temperature, ant an unnamed zeolite emerges when prolonging crystallization time or raising crystalli-zation, temperature. SEM micrographs suggest that the aggregates of Na-X zeolite particles have perfect dispersity and uniform granular with about 1.5 μm in size, and most of the Na-X zeolite crystals display a regular octahedral structure with the size of about 500 nm. The specific surface area of the powders with single Na-X zeolite phase reaches the maximum value of 488. 163 2 m2· g -1, larger than that of multiple zeolite powders.
文摘The microstructure and the mechanical properties of hardened mortars made of superplasticized composite binder containing shale ash and fly ash are investigated. The pozzolanic reaction consumes the oriented Ca (OH)//2 crystals, thus making the transition zone dense. Appropriately proportioning of shale ash and fly ash decreases the water requirement and increases the packing density of composite binder mortars, therefore increases their strength. Superplasticizer promotes the carbonation of calcium hydrates and the formation of ettringite that is transformed gradually into mono-sulfoaluminate hydrate in composite binder mortars. The joint action of fine complex mineral admixture and superplasticizer has a synergistic effect to improve the mechanical properties of composite binder. (Author abstract) 7 Refs.
文摘This paper presents the first study on the oil shale (OS) ashing and OS ash leachability of Jordanian OS located further in the south. The studied OS is from Isfir Al-Mahata subsurface OS located 10 km south of Ma’an. Chemical and physical characterization of the OS ash was performed and compared with original OS. Ashing OS was conducted at different temperatures. Important parameters affecting OS ash leachability were also investigated. The leachability of certain heavy metals was investigated based on clear leaching protocol. The Fisher Assay analysis result indicates that this OS type has quite higher moisture content, lower oil content, and higher spent shale compared with other Jordanian oil shales. Ashing of OS at higher temperatures (950°C) resulted in the disappearance of silica, due to its complete reaction with lime and Al, and formation of Anhydrite and cement materials like, Portland cement. The leachability analysis indicates that for most elements the leachability is high at low pH. The released heavy metals concentrations are below EPA limits. Chromium and lead are leached out more than other elements with the exception at low pH. In general, the higher the ashing temperature is, the lower the release of elements is. The chemical composition of the ash and the leachability results suggests that it has high fixing capacity toward the heavy metals present in the ash.
基金the National Basic Research Program of China(973 Program,Grant 2014CB744301).
文摘Na-X zeolites were synthesized by Longkou oil shale ash with the alkaline fusion hydrothermal method.The effects of fusion temperature,ash to NaOH ratio,solid-liquid ratio,crystallization time and crystallization temperature on the crystallinity of zeolites were investigated.The synthetic products were characterized by Xray diffraction(XRD),scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),29Si nuclear magnetic resonance spectroscopy(29Si NMR)and N2 adsorption-desorption.The results showed that the conditions to synthesize Na-X zeolite were:Longkou oil shale ash to sodium hydroxide ratio 1:1.2 g・g^(-1),fusion temperature 600℃,solid-liquid ratio 1:4 g・mL^(-1),crystallization time 24 h and crystallization temperature 80℃.The zeolite with high crystallinity(91.32%)was synthesized:the product exhibiting octahedral particles observed by SEM,and the calculated Si/Al ratio in Na-X zeolite being 1.23 from^(29)Si MAS NMR spectra,which was consistent with the observation from XRD.
