Colloidal gas aphrons(CGAs) were first defined by Sebba( J.Colloid Interface Sci .,1971,35(4):643) as micro bubbles(25—300?μm).These microbubbles do not coalesce easily and are markedly different from conventional s...Colloidal gas aphrons(CGAs) were first defined by Sebba( J.Colloid Interface Sci .,1971,35(4):643) as micro bubbles(25—300?μm).These microbubbles do not coalesce easily and are markedly different from conventional soap bubbles in their stability and flow properties.CGAs are composed of a gaseous inner core surrounded by a thin surfactant film, which are created by intense stirring of a surfactant solution. CGA dispersion typically contains about 65% gas. CGA suspensions have viscosity similar to water, which make them suitable for pumping without deterioration in quality. Two important considerations in the application of CGA suspensions are: ① their colloidal size, resulting in a large surface area to volume ratio, and ② the existence of a double film of surfactant encapsulating the gas that retards the coalescence of the bubble. CGA suspensions are found very effective for separating hydrophobic organic compounds and heavy metal ions. In this paper, flotation of Cu(Ⅱ) by colloidal gas aphrons has been conducted in order to explore a new method for separating heavy metal ions from dilute solution. The effects of CGA flow rate, amounts of CGA introduced to the system, surfactant concentration on the flotation efficiency have been systematically investigated. The optimum flotation condition is determined. The results show that flotation efficiency at pH=5—6 has an optimum value to CGA flow rate and amount. When pH is greater than 7, the flotation efficiency can be as high as 99% at the optimum condition.展开更多
To investigate effect of metallic ion activation on different particle sizes of quartz in butyl xanthate solution,six common ions(Pb^(2+),Cu^(2+),Fe^(3+),Fe^(2+),Mg^(2+) and Ca^(2+)) were introduced as activators.The ...To investigate effect of metallic ion activation on different particle sizes of quartz in butyl xanthate solution,six common ions(Pb^(2+),Cu^(2+),Fe^(3+),Fe^(2+),Mg^(2+) and Ca^(2+)) were introduced as activators.The approaches of micro-flotation,adsorption test and zeta potential measurement were adopted to reveal the mechanism of ion activation.The results show that Pb^(2+),Cu^(2+) and Fe^(3+) are effective activators for the flotation of quartz in butyl xanthate solution because of their absorption on activated quartz surface.Average recoveries of fine particles(<37 μm) are greater than those of coarser particles(37-74 μm),suggesting that the former is easier to be activated and more likely to be floated and thus entrained in sulphide concentrate.From another perspective,addition of metallic ions(Pb^(2+),Cu^(2+) and Fe^(3+)) renders zeta potentials move positively,and addition of the same metallic ions and butyl xanthate makes zeta potential drop apparently,which support a mechanism where they adsorb onto quartz surface,resulting in an expected increase in butyl xanthate collector adsorption with a concomitant increase in the flotation recoveries.展开更多
The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as(3-Mercaptopropyl) tri...The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as(3-Mercaptopropyl) triethoxysilane(MPTES) and(3-Amincpropyl) trithoxysilane(APTES). Some further modifications were studied by chloroaceetyl choride and 1,8-Diaminoaphalene for amino modified silica. The surface functionalized silica nanoparticles were characterized by Fourier transform infrared(FI-IR) and X-ray photoelectron spectroscopy(XPS). The prepared adsorbent of surface functionalized silica nanoparticles with differential function groups were investigated in the selective adsorption about Pb2+, Cu2+, Hg2+, Cd2+ and Zn2+ions in aqueous solutions. The results show that the(3-Mercaptopropyl) triethoxysilane functionalized silica nanoparticles(SiO2-MPTES) play an important role in the selective adsorption of Cu2+ and Hg2+, the(3-Amincpropyl) trithoxysilane(APTES) functionalized silica nanoparticles(SiO2-APTES) exhibited maximum removal efficiency towards Pb2+ and Hg2+, the 1,8-Diaminoaphalene functionalized silica nanoparticles was excellent for removal of Hg2+ at room temperature, respectively.展开更多
文摘Colloidal gas aphrons(CGAs) were first defined by Sebba( J.Colloid Interface Sci .,1971,35(4):643) as micro bubbles(25—300?μm).These microbubbles do not coalesce easily and are markedly different from conventional soap bubbles in their stability and flow properties.CGAs are composed of a gaseous inner core surrounded by a thin surfactant film, which are created by intense stirring of a surfactant solution. CGA dispersion typically contains about 65% gas. CGA suspensions have viscosity similar to water, which make them suitable for pumping without deterioration in quality. Two important considerations in the application of CGA suspensions are: ① their colloidal size, resulting in a large surface area to volume ratio, and ② the existence of a double film of surfactant encapsulating the gas that retards the coalescence of the bubble. CGA suspensions are found very effective for separating hydrophobic organic compounds and heavy metal ions. In this paper, flotation of Cu(Ⅱ) by colloidal gas aphrons has been conducted in order to explore a new method for separating heavy metal ions from dilute solution. The effects of CGA flow rate, amounts of CGA introduced to the system, surfactant concentration on the flotation efficiency have been systematically investigated. The optimum flotation condition is determined. The results show that flotation efficiency at pH=5—6 has an optimum value to CGA flow rate and amount. When pH is greater than 7, the flotation efficiency can be as high as 99% at the optimum condition.
基金Project(51274255)supported by the National Natural Science Foundation of ChinaProject(2015CX005)supported by Innovation Driven Plan of Central South University,China+1 种基金Project(2016RS2016)supported by Hunan Provincial Science and Technology Leader(Innovation Team of Interface Chemistry of Efficient and Clean Utilization of Complex Mineral Resources),ChinaProject supported by the Postdoctoral Research Station of Central South University,China
文摘To investigate effect of metallic ion activation on different particle sizes of quartz in butyl xanthate solution,six common ions(Pb^(2+),Cu^(2+),Fe^(3+),Fe^(2+),Mg^(2+) and Ca^(2+)) were introduced as activators.The approaches of micro-flotation,adsorption test and zeta potential measurement were adopted to reveal the mechanism of ion activation.The results show that Pb^(2+),Cu^(2+) and Fe^(3+) are effective activators for the flotation of quartz in butyl xanthate solution because of their absorption on activated quartz surface.Average recoveries of fine particles(<37 μm) are greater than those of coarser particles(37-74 μm),suggesting that the former is easier to be activated and more likely to be floated and thus entrained in sulphide concentrate.From another perspective,addition of metallic ions(Pb^(2+),Cu^(2+) and Fe^(3+)) renders zeta potentials move positively,and addition of the same metallic ions and butyl xanthate makes zeta potential drop apparently,which support a mechanism where they adsorb onto quartz surface,resulting in an expected increase in butyl xanthate collector adsorption with a concomitant increase in the flotation recoveries.
基金Project(2012CB722803)supported by the Key Project of National Basic Research and Development Program of ChinaProject(U1202271)supported by the National Natural Science Foundation of ChinaProject(IRT1250)supported by the Program for Innovative Research Team in University of Ministry of Education of China
文摘The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as(3-Mercaptopropyl) triethoxysilane(MPTES) and(3-Amincpropyl) trithoxysilane(APTES). Some further modifications were studied by chloroaceetyl choride and 1,8-Diaminoaphalene for amino modified silica. The surface functionalized silica nanoparticles were characterized by Fourier transform infrared(FI-IR) and X-ray photoelectron spectroscopy(XPS). The prepared adsorbent of surface functionalized silica nanoparticles with differential function groups were investigated in the selective adsorption about Pb2+, Cu2+, Hg2+, Cd2+ and Zn2+ions in aqueous solutions. The results show that the(3-Mercaptopropyl) triethoxysilane functionalized silica nanoparticles(SiO2-MPTES) play an important role in the selective adsorption of Cu2+ and Hg2+, the(3-Amincpropyl) trithoxysilane(APTES) functionalized silica nanoparticles(SiO2-APTES) exhibited maximum removal efficiency towards Pb2+ and Hg2+, the 1,8-Diaminoaphalene functionalized silica nanoparticles was excellent for removal of Hg2+ at room temperature, respectively.
