Traditional treatments of zinc dross have many disadvantages,such as complicated recovering process and serious environmental pollution.In this work,a new process of chlorine removal from zinc dross by microwave was p...Traditional treatments of zinc dross have many disadvantages,such as complicated recovering process and serious environmental pollution.In this work,a new process of chlorine removal from zinc dross by microwave was proposed for solving problem of recycling the zinc dross.With better ability of absorbing the microwave than zinc oxide,the main material in zinc dross,chlorides,can be heated and evaporated rapidly during microwave roasting.Various parameters including roasting temperature,duration time and stirring speed were optimized.The microstructure of roasted materials was characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM).The content of the chloride was analyzed by the method of chlorine ion selective electrode.The experiments indicate that the best duration time is 60 min with a stirring speed of 15 r/min during the microwave roasting process.The dechlorination rate reaches peak value of 88% at 700 ℃.The chlorine is removed as HCl gas when water vapor is used as activating agent,which means that it can be recovered into hydrochloride acid.展开更多
A method for in situ preparation of fluorescent gold nanoclusters(Au NCs) with bovine serum albumin/montmorillonite composite powder(Au NC-BSA/MMT) was developed, and the products were used to detect latent fingermark...A method for in situ preparation of fluorescent gold nanoclusters(Au NCs) with bovine serum albumin/montmorillonite composite powder(Au NC-BSA/MMT) was developed, and the products were used to detect latent fingermarks. In this work, Au NCs were "grown" both inside and on the surface of BSA/MMT clay using one-step reduction of HAu Cl4 by BSA. The as-prepared Au NC-BSA/MMT nanocomposites emit intensive red fluorescence under the excitation of UV-visible light and show stable chemical features and low toxicity. The obtained fluorescent powders were characterized by UV-visible absorption spectroscopy,fluorescence spectroscopy, infrared spectroscopy, transmission electron microscopy/high-resolution transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction to depict their sizes, structural information and optical features. Given their environmentally friendly preparation, simple operation, low cost, efficient UVvisible radiation-dependent photoluminescence and good affinity with finger residues, the in situ synthesized Au NC-BSA/MMT nanocomposite powders were used as an alternative fluorescent developing reagent for developing latent fingermarks deposited on various object surfaces(such as glass, aluminum foil, painted metal, plastic products and weighing papers) for individual identification. As results, the developed fingermarks with clear patterns and satisfactory level-2(minutiae points) and level-3(sweat pores) ridge details were obtained. Notably, treated prints could be excited by red light and emitted near infrared fluorescence, which was beneficial to avoid background interference and reduce the damage caused by UV light. With the advantages of the simple preparation process and good enhancement performance for latent fingermarks, the proposed method might be used in the preparation of various fluorescent probes for detecting trace evidence in forensic sciences.展开更多
基金Project(51104073) supported by the National Natural Science Foundation of China
文摘Traditional treatments of zinc dross have many disadvantages,such as complicated recovering process and serious environmental pollution.In this work,a new process of chlorine removal from zinc dross by microwave was proposed for solving problem of recycling the zinc dross.With better ability of absorbing the microwave than zinc oxide,the main material in zinc dross,chlorides,can be heated and evaporated rapidly during microwave roasting.Various parameters including roasting temperature,duration time and stirring speed were optimized.The microstructure of roasted materials was characterized by X-ray diffraction(XRD) and scanning electron microscope(SEM).The content of the chloride was analyzed by the method of chlorine ion selective electrode.The experiments indicate that the best duration time is 60 min with a stirring speed of 15 r/min during the microwave roasting process.The dechlorination rate reaches peak value of 88% at 700 ℃.The chlorine is removed as HCl gas when water vapor is used as activating agent,which means that it can be recovered into hydrochloride acid.
基金supported by the National Natural Science Foundation of China(51401174)the National Social Science Foundation of China(16AYY015)the Scientific Research Funds of Southwest University of Political Science and Law(2015XZQN-32)
文摘A method for in situ preparation of fluorescent gold nanoclusters(Au NCs) with bovine serum albumin/montmorillonite composite powder(Au NC-BSA/MMT) was developed, and the products were used to detect latent fingermarks. In this work, Au NCs were "grown" both inside and on the surface of BSA/MMT clay using one-step reduction of HAu Cl4 by BSA. The as-prepared Au NC-BSA/MMT nanocomposites emit intensive red fluorescence under the excitation of UV-visible light and show stable chemical features and low toxicity. The obtained fluorescent powders were characterized by UV-visible absorption spectroscopy,fluorescence spectroscopy, infrared spectroscopy, transmission electron microscopy/high-resolution transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction to depict their sizes, structural information and optical features. Given their environmentally friendly preparation, simple operation, low cost, efficient UVvisible radiation-dependent photoluminescence and good affinity with finger residues, the in situ synthesized Au NC-BSA/MMT nanocomposite powders were used as an alternative fluorescent developing reagent for developing latent fingermarks deposited on various object surfaces(such as glass, aluminum foil, painted metal, plastic products and weighing papers) for individual identification. As results, the developed fingermarks with clear patterns and satisfactory level-2(minutiae points) and level-3(sweat pores) ridge details were obtained. Notably, treated prints could be excited by red light and emitted near infrared fluorescence, which was beneficial to avoid background interference and reduce the damage caused by UV light. With the advantages of the simple preparation process and good enhancement performance for latent fingermarks, the proposed method might be used in the preparation of various fluorescent probes for detecting trace evidence in forensic sciences.
