Ca(OH)2 nanoparticles in hydro-alcoholic dispersion (nanolime) were successfully employed in Cultural Heritage conservation, thanks to the ability to overcome the limiting aspects of traditional lime treatments. Nanol...Ca(OH)2 nanoparticles in hydro-alcoholic dispersion (nanolime) were successfully employed in Cultural Heritage conservation, thanks to the ability to overcome the limiting aspects of traditional lime treatments. Nanolime were currently produced by chemical precipitation process, at high temperature, with long times of synthesis, and after several purification steps to remove undesired secondary phases. In this paper, an innovative, simple and original method for nanolime production was described. The method was based on an ion exchange process between an anionic resin and a calcium chloride aqueous solution, operating at room temperature. A pure Ca(OH)2 nanoparticles suspension can be rapidly obtained after separating the resin from suspension, and any purification step was necessary. The exhausted resins can be regenerated and reused for a cyclic nanolime production. Structural and morphological features of the produced nanolime were preliminarily characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Moreover, XRD measurements allowed estimating nanoparticles reactivity by following their carbonatation process in air, in relation to different water/alcohol ratios and medium or high relative humidity conditions. The produced Ca(OH)2 nanoparticles appeared hexagonally plated, with dimension less than 100 nm and, compared with those obtained by typical wet precipitation method, they proved to be more reactive.展开更多
The leaching of magnesium from desiliconization slag of nickel laterite ores by carbonation process was studied.The influence of various parameters was investigated to optimize the conditions and determine the kinetic...The leaching of magnesium from desiliconization slag of nickel laterite ores by carbonation process was studied.The influence of various parameters was investigated to optimize the conditions and determine the kinetics of the reaction.The results show that with increasing stirring speed,liquid-to-solid ratio and reaction time,and decreasing temperature,the leaching rate of magnesium enhances.The leaching process of the desiliconization slag in the range of 288-298 K is controlled by the surface chemical reaction model.The apparent activation energy is-20.45 kJ/mol,and the kinetics model is obtained.展开更多
By applying the reinforcing and toughening effect of calcium carbonate （CaCO3） nanoparticles on polypropylene, foam sheets of good performance were successfully fabricated by extrusion. The equipment and conditions ...By applying the reinforcing and toughening effect of calcium carbonate （CaCO3） nanoparticles on polypropylene, foam sheets of good performance were successfully fabricated by extrusion. The equipment and conditions of the extrusion were explored. The mechanical properties of the produced foam sheets were tested. The effect of CaCO3 nano-particles on the mechanical properties and the cellular structure of the sheets was comprehensively studied. The experimental results show that the optimum content of CaCO3 nano-particles in the composite material was -4wt%. At this content, the nano-particles were well dispersed in the substrate, and the composite material had maximum tensile strength and impact strength. Surface treatment of the nano-particles only affected the impact strength of the composite material. CaCO3 micro-particles, on the other hand, showed little effect on the properties of the composite material when the micro-particles content was less than 5 wt%. At a content higher than 5wt%, the properties of the composite material significantly worsened.展开更多
Eggshell powder is a powdered product that is made from discarded eggshells. It is rich in inorganic salts and a small number of organic substances. Aliphatic polyester is one of the most promising polymer materials a...Eggshell powder is a powdered product that is made from discarded eggshells. It is rich in inorganic salts and a small number of organic substances. Aliphatic polyester is one of the most promising polymer materials at present. Aliphatic polyester has not only a wide range of sources, but also excellent biodegradability and biocompatibility. Three kinds of aliphatic polyester composites were mixed with PCL, PBS, PHA, PLA and Ag powder as raw materials through solution reinforcement by eggshell powder. The thermal properties and structures of the three materials were analyzed and characterized by differential scanning calorimetry and scanning electron microscopy. DSC and SEM were used to analyze and characterize the thermal properties and structures of the three composites. The experimental results show that the GTT(glass-transition temperature) are 91.9°C, 89.3°C, and 87.2°C, the melting points are all greater than 92°C, and the enthalpy changes are respectively -37.8J/g, -23.9J/g, -22.2 J/g,. Among them, the composite material of PCL, PBS and eggshell powder, and Ag powder has excellent performance, showing good thermal performance and thermal stability. Moreover, the production and utilization of eggshell powder, turning waste into wealth, has important economic value for the sustainable development of circular ecology.展开更多
文摘Ca(OH)2 nanoparticles in hydro-alcoholic dispersion (nanolime) were successfully employed in Cultural Heritage conservation, thanks to the ability to overcome the limiting aspects of traditional lime treatments. Nanolime were currently produced by chemical precipitation process, at high temperature, with long times of synthesis, and after several purification steps to remove undesired secondary phases. In this paper, an innovative, simple and original method for nanolime production was described. The method was based on an ion exchange process between an anionic resin and a calcium chloride aqueous solution, operating at room temperature. A pure Ca(OH)2 nanoparticles suspension can be rapidly obtained after separating the resin from suspension, and any purification step was necessary. The exhausted resins can be regenerated and reused for a cyclic nanolime production. Structural and morphological features of the produced nanolime were preliminarily characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Moreover, XRD measurements allowed estimating nanoparticles reactivity by following their carbonatation process in air, in relation to different water/alcohol ratios and medium or high relative humidity conditions. The produced Ca(OH)2 nanoparticles appeared hexagonally plated, with dimension less than 100 nm and, compared with those obtained by typical wet precipitation method, they proved to be more reactive.
基金Project(2007CB613603)supported by the National Basic Research Program of China
文摘The leaching of magnesium from desiliconization slag of nickel laterite ores by carbonation process was studied.The influence of various parameters was investigated to optimize the conditions and determine the kinetics of the reaction.The results show that with increasing stirring speed,liquid-to-solid ratio and reaction time,and decreasing temperature,the leaching rate of magnesium enhances.The leaching process of the desiliconization slag in the range of 288-298 K is controlled by the surface chemical reaction model.The apparent activation energy is-20.45 kJ/mol,and the kinetics model is obtained.
基金the National Natural Science Foundation of China(No.19632004 and 10172074)
文摘By applying the reinforcing and toughening effect of calcium carbonate （CaCO3） nanoparticles on polypropylene, foam sheets of good performance were successfully fabricated by extrusion. The equipment and conditions of the extrusion were explored. The mechanical properties of the produced foam sheets were tested. The effect of CaCO3 nano-particles on the mechanical properties and the cellular structure of the sheets was comprehensively studied. The experimental results show that the optimum content of CaCO3 nano-particles in the composite material was -4wt%. At this content, the nano-particles were well dispersed in the substrate, and the composite material had maximum tensile strength and impact strength. Surface treatment of the nano-particles only affected the impact strength of the composite material. CaCO3 micro-particles, on the other hand, showed little effect on the properties of the composite material when the micro-particles content was less than 5 wt%. At a content higher than 5wt%, the properties of the composite material significantly worsened.
文摘Eggshell powder is a powdered product that is made from discarded eggshells. It is rich in inorganic salts and a small number of organic substances. Aliphatic polyester is one of the most promising polymer materials at present. Aliphatic polyester has not only a wide range of sources, but also excellent biodegradability and biocompatibility. Three kinds of aliphatic polyester composites were mixed with PCL, PBS, PHA, PLA and Ag powder as raw materials through solution reinforcement by eggshell powder. The thermal properties and structures of the three materials were analyzed and characterized by differential scanning calorimetry and scanning electron microscopy. DSC and SEM were used to analyze and characterize the thermal properties and structures of the three composites. The experimental results show that the GTT(glass-transition temperature) are 91.9°C, 89.3°C, and 87.2°C, the melting points are all greater than 92°C, and the enthalpy changes are respectively -37.8J/g, -23.9J/g, -22.2 J/g,. Among them, the composite material of PCL, PBS and eggshell powder, and Ag powder has excellent performance, showing good thermal performance and thermal stability. Moreover, the production and utilization of eggshell powder, turning waste into wealth, has important economic value for the sustainable development of circular ecology.
