Zeolite synthesized from fly ash （ZFA） without modification is not efficient for the purification of NH4＋ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacit...Zeolite synthesized from fly ash （ZFA） without modification is not efficient for the purification of NH4＋ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 （≥0.9 mol/L） resulted in a limited maximum phosphate immobilization capacity （PIC）. It was concluded that through a previous mild acid treatment （e.g. 0.01 mol/L of H2SO4）, ZFA can be used in the simultaneous removal of NH4＋ and P at low concentrations simulating real effluent.展开更多
Calcium phosphate film was prepared by electrochemical deposition technology. Subsequently, the alkaline treatment process of calcium phosphate film in 0.1 mol/L NaOH solution was monitored on real time by the piezoel...Calcium phosphate film was prepared by electrochemical deposition technology. Subsequently, the alkaline treatment process of calcium phosphate film in 0.1 mol/L NaOH solution was monitored on real time by the piezoelectric quartz crystal impedance (PQCI) technique. The variations of morphology and composition for the alkaline treatment products were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD), respectively. The dynamic variations of calcium phosphate can be characterized by the change of equivalent circuit parameters. The results show that the forming process of hydroxyapatite (HA) is composed of three stages: (1) acidic calcium phosphate dissolution; (2) phase transformation; and (3) HA formation. Furthermore, the correlative kinetic equations and parameters are obtained by fitting the static capacitance (Cs)—time curves.展开更多
Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition we...Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition were evaluated. The X-ray diffractometry results show that CaHPO4·2H2O is obtained as the kind of calcium phosphate coating on carbon fiber. The scanning electron microscopy photographs and deposit kinetic curve indicate that the influences of the functional group attained by nitric acid treatment, the crystal morphology and crystallization of the coating layers on the fiber with and without treatment rate are obviously different. The functional group, especially the acidic group, can act as nucleation centers of electrochemical crystallization.展开更多
In the framework of various phosphates discharges valorization, we have realized physicochemical and mineralogical characterizations of these discharges. We have undertaken the physicochemical and mineralogical charac...In the framework of various phosphates discharges valorization, we have realized physicochemical and mineralogical characterizations of these discharges. We have undertaken the physicochemical and mineralogical characterizations of this waste by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), thermal analysis and Atomic Emission Spectrometry Coupled to an Inductive Plasma Source. The results of these analyze show that phosphate sludge and screen rejects could be used in ceramics, in the manufacture of aggregates, in agriculture and other fields. On the other hand, rich magnetic waste could be used in heterogeneous photocatalysis in waste liquids treatment.展开更多
Porous and dense TiNi alloys were successfully fabricated by powder metallurgy(P/M) method, and to further improve their surface biocompatibility, surface modification techniques including grind using silicon-carbide(...Porous and dense TiNi alloys were successfully fabricated by powder metallurgy(P/M) method, and to further improve their surface biocompatibility, surface modification techniques including grind using silicon-carbide(SiC) paper, acid etching and alkali treatment were employed to produce either irregularly rough surface or micro-porous surface roughness. X-ray diffractometry(XRD), scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDX) attached to SEM were used to characterize surface structure and the Ca-P coatings. Effects of the above surface treatments on the surface morphology, apatite forming ability were systematically investigated. Results indicate that all the above surface treatments increase the apatite forming ability of TiNi alloys in varying degrees when soaked in simulated body fluid(SBF). More apatite coatings formed on TiNi samples sintered at 1050℃ and 1100℃ due to their high porosity and pure TiNi phase that is beneficial to heterogeneous nucleation. Furthermore, more uniform apatite was fabricated on the sample sintered from the mixture of Ni and Ti powders.展开更多
The calcium phosphate cement (α-TCP/TTCP) was reinforced with oxidation-t reated carbon fibers. The effect of aspect ratio and content of carbon fiber on the compression strength and bending strength of the hardened ...The calcium phosphate cement (α-TCP/TTCP) was reinforced with oxidation-t reated carbon fibers. The effect of aspect ratio and content of carbon fiber on the compression strength and bending strength of the hardened body was discussed . The results show that the reinforcing effect is optimal as the aspect ratio is 375 and the additive amount is 0.3%(mass fraction). Under this condition,the c ompressive strength is increased by 55% (maximum 63.46 MPa),and the bending st rength is nearly increased by 100% (maximum 11.95 MPa),respectively. However,if the additive quantity and aspect ratio are too high,the effect of the carbon fibers is limited because it can not be dispersed uniformly in the hardened bod y. The biological evaluation indicates that the calcium phosphate cement reinfor ced by carbon fibers has good biocompatibility.展开更多
It is necessary to adjust reaction pH when a single kind of PO3-4 is used as phosphorus source to remove NH+4-N in a chemical precipitation process.However,this tedious step could be avoided in experiments that use th...It is necessary to adjust reaction pH when a single kind of PO3-4 is used as phosphorus source to remove NH+4-N in a chemical precipitation process.However,this tedious step could be avoided in experiments that use the buffering effect of the composite phosphate and employ PO3-4 and HPO2-4 as phosphorus sources.pH was controlled by properly changing the proportion of PO3-4 to HPO2-4.The influences of pH,material proportion and different addition modes of magnesium on NH+4-N removal efficiency were investigated,with NH+4-N concentration in influent being 200mg/L.It showed that the ratio of HPO2-4:PO3-4 was concerned with phosphorus and NH+4-N removal.Under the condition that the total amount of phosphate is definite,the removal efficiency of NH+4-N decreased with the enhancement of HPO2-4 concentration,while the efficiency of phosphorus increased.When increasing PO3-4 concentration,it benefited the removal of NH+4-N,but the remaining phosphorus was high.The results showed that NH+4-N concentration decreased from the initial 200mg/L to 39.14mg/L with the remaining PO3-4 at 5.14mg/L if the ratio of HPO2-4:PO3-4 remained at 1:3.展开更多
基金Project supported by the Chinese Ministry of Science and Technology Funding (No. 2002AA601013).
文摘Zeolite synthesized from fly ash （ZFA） without modification is not efficient for the purification of NH4＋ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 （≥0.9 mol/L） resulted in a limited maximum phosphate immobilization capacity （PIC）. It was concluded that through a previous mild acid treatment （e.g. 0.01 mol/L of H2SO4）, ZFA can be used in the simultaneous removal of NH4＋ and P at low concentrations simulating real effluent.
基金Project(2005CB623901) supported by the Major State Basic Research and Development Program of China
文摘Calcium phosphate film was prepared by electrochemical deposition technology. Subsequently, the alkaline treatment process of calcium phosphate film in 0.1 mol/L NaOH solution was monitored on real time by the piezoelectric quartz crystal impedance (PQCI) technique. The variations of morphology and composition for the alkaline treatment products were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD), respectively. The dynamic variations of calcium phosphate can be characterized by the change of equivalent circuit parameters. The results show that the forming process of hydroxyapatite (HA) is composed of three stages: (1) acidic calcium phosphate dissolution; (2) phase transformation; and (3) HA formation. Furthermore, the correlative kinetic equations and parameters are obtained by fitting the static capacitance (Cs)—time curves.
基金Project (2003AA302210) supported by the National High Technology Research and Development Program of Chinaproject(04JJ3083) supported by the Elite Foundation of Hunan Province+1 种基金 China project (030615) supported by the Innovation Pro
文摘Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition were evaluated. The X-ray diffractometry results show that CaHPO4·2H2O is obtained as the kind of calcium phosphate coating on carbon fiber. The scanning electron microscopy photographs and deposit kinetic curve indicate that the influences of the functional group attained by nitric acid treatment, the crystal morphology and crystallization of the coating layers on the fiber with and without treatment rate are obviously different. The functional group, especially the acidic group, can act as nucleation centers of electrochemical crystallization.
文摘In the framework of various phosphates discharges valorization, we have realized physicochemical and mineralogical characterizations of these discharges. We have undertaken the physicochemical and mineralogical characterizations of this waste by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), thermal analysis and Atomic Emission Spectrometry Coupled to an Inductive Plasma Source. The results of these analyze show that phosphate sludge and screen rejects could be used in ceramics, in the manufacture of aggregates, in agriculture and other fields. On the other hand, rich magnetic waste could be used in heterogeneous photocatalysis in waste liquids treatment.
基金Project(51274247) supported by the National Natural Science Foundation of ChinaProject(2014zzts177) support by the Fundamental Research Funds for the Central Universities,China
文摘Porous and dense TiNi alloys were successfully fabricated by powder metallurgy(P/M) method, and to further improve their surface biocompatibility, surface modification techniques including grind using silicon-carbide(SiC) paper, acid etching and alkali treatment were employed to produce either irregularly rough surface or micro-porous surface roughness. X-ray diffractometry(XRD), scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDX) attached to SEM were used to characterize surface structure and the Ca-P coatings. Effects of the above surface treatments on the surface morphology, apatite forming ability were systematically investigated. Results indicate that all the above surface treatments increase the apatite forming ability of TiNi alloys in varying degrees when soaked in simulated body fluid(SBF). More apatite coatings formed on TiNi samples sintered at 1050℃ and 1100℃ due to their high porosity and pure TiNi phase that is beneficial to heterogeneous nucleation. Furthermore, more uniform apatite was fabricated on the sample sintered from the mixture of Ni and Ti powders.
文摘The calcium phosphate cement (α-TCP/TTCP) was reinforced with oxidation-t reated carbon fibers. The effect of aspect ratio and content of carbon fiber on the compression strength and bending strength of the hardened body was discussed . The results show that the reinforcing effect is optimal as the aspect ratio is 375 and the additive amount is 0.3%(mass fraction). Under this condition,the c ompressive strength is increased by 55% (maximum 63.46 MPa),and the bending st rength is nearly increased by 100% (maximum 11.95 MPa),respectively. However,if the additive quantity and aspect ratio are too high,the effect of the carbon fibers is limited because it can not be dispersed uniformly in the hardened bod y. The biological evaluation indicates that the calcium phosphate cement reinfor ced by carbon fibers has good biocompatibility.
文摘It is necessary to adjust reaction pH when a single kind of PO3-4 is used as phosphorus source to remove NH+4-N in a chemical precipitation process.However,this tedious step could be avoided in experiments that use the buffering effect of the composite phosphate and employ PO3-4 and HPO2-4 as phosphorus sources.pH was controlled by properly changing the proportion of PO3-4 to HPO2-4.The influences of pH,material proportion and different addition modes of magnesium on NH+4-N removal efficiency were investigated,with NH+4-N concentration in influent being 200mg/L.It showed that the ratio of HPO2-4:PO3-4 was concerned with phosphorus and NH+4-N removal.Under the condition that the total amount of phosphate is definite,the removal efficiency of NH+4-N decreased with the enhancement of HPO2-4 concentration,while the efficiency of phosphorus increased.When increasing PO3-4 concentration,it benefited the removal of NH+4-N,but the remaining phosphorus was high.The results showed that NH+4-N concentration decreased from the initial 200mg/L to 39.14mg/L with the remaining PO3-4 at 5.14mg/L if the ratio of HPO2-4:PO3-4 remained at 1:3.
