| Industrial waste water characterizes enormous quantities and complex composition. It contains multiscale fine particles, such as molecular pollutants, composed of raw materials, intermediate, solid particles catalyst entrained in reaction, and oil phase which were escaped from equipments. As pointed out above, there are more factors affecting separation of waste water, and it makes the separation complex. Meanwhile, an efficient separation of fine particles in waste water play an important role in improving some problems, for example, the climate changes, environmental damage, caused by new energy majored in coal chemical engineering. Removal and recycling of fine particles by filtration with procoat in complex waste water have becoming a hotspot in its field for its brand prospect. However, it's difficult to meet the requirements of modern separation detection through traditional macroscopic evaluation method.This study developed a rapid and quantitative method for detection on multi-scale fine particle in filtration. Based on in-situ test of surface enhanced Raman spectroscopy (SERS) detection, it gave play to microfluidic technology as the basic research tool, aiming at complex composition of fine particles in waste water, to research separation of different components in filtration:adsorption process of soluble molecules, extraction process in micro channel formed by oil and water phase among particles, filtration process of solid particles in precoat. The thesis also developed a method of in-situ quantitative detection contaminants on the surface of single particle in adsorption process through SERS-active porous microspheres, designed dynamic laminar flow extraction system to monitor the extraction process of ion movement at different stages of oil or water interface in real time. A new type of SERS nano sensor was designed to detect the trajectories of particles in suspension during the process of precoat and filtering, and applied method of rapid detection to actual productive process. Research results were displayed as follow. (1) Fabrication of SERS-active porous microspheresA green method was developed to fabricate a novel porous polymer microsphere with SERS activity that can be used for ultrasensitive detection because of its preconcentration function. UV irradiation as "green" reduction was successfully achieved through several complex processes, namely, monomer solidification, hydrogen peroxide photolysis, and silver nanoparticle fabrication, in only one step. Firstly, the O/W emulsion template was prepared by homemade microfluidic glass capillary tube. Through controlling the concentration of hydrogen peroxide accurately to control the speed of oxygen and water, deoxidized oxygen escapes from template while emulsion template solidified. Then, staggered micro channels spread all over the surface and interior were come into being. The average diameter of achieved porous microspheres is 4 ?m, and the specific surface area reaches 31 m2/g. At the same time of porous microspheres'formation, silver nanoparticles deoxidized by silver nitrate deposited on surface of porous microspheres which endows it good activity of SERS. And the enhancement factor (EF) of SERS reaches 3.8x106. The functionalized porous microspheres make foundation for on-site qualitative and semi-quantitative rapid detection on surface contaminants of single particle.(2) In-situ quantitative detection of pollutants which were adsorbed on the surface of single particleSelecting a typical separation process, chosen a dynamic hydrocyclone adsorption process as the research system, an in-situ quantitative detection on surface contaminants of single-particle with SERS has been realized for the first time. First of all, applying the SERS-active porous microspheres to accomplish adsorption process in the vortex flow adsorption technology and obtain the SERS spectra of surface contaminants in microspheres through a portable Raman spectrometer. Secondly, the quality of contaminants on porous microspheres per unit mass can be calculated by material balance. Finally, a dual logarithm curve, described the relationship between intensity of SERS characteristic peak on pollutant and quality of pollutants which were absorbed on porous microspheres, can be build up. Through the curve, on-site detection in real time of contaminants in surface of single particle can be accomplished.(3) In-situ analysis of dynamic laminar flow extraction using surface-enhanced Raman spectroscopyProcess of dynamic laminar flow extraction was monitored though combination of microfluidic and SERS technology. Based on aggregation of chloride ion impelled on silver nanoparticles, accurate control of time for extraction of chloride ion and elaborate subdivision in extraction process which belong to microfluidic technology are implemented to realize research both on detection in real time on extraction of chloride ion and the kinetics of it through monitoring the variation of concentration of chloride ion in different diffusion time and different location in laminar diffusion system by the intensity of SERS in characteristic peak of R6G. Meanwhile, the extraction efficiency of chloride ion can be regulated by changing the concentration of chloride ion in oil phase and extraction conditions. On-line detection on dynamic laminar flow extraction has been established, and it's also can be applied to other ions which can cause aggregation of gold and silver nanoparticles. This method provides with strong theoretical support and technical guidance to the efficiency of oil extraction in industrial productions.(4) SERS Detection and regulation the process of precoat filtrationFactors and methods of regulation which influenced the process of precoat and filtering have been studied through laboratory experiment and pilot test by microfluidic device, with the surface enhanced Raman spectroscopy technology. Filter aids were introduced to precoat in typical filtration so as to regulate the specific resistance of cakes. This measure solved problem of rapid termination which caused by fast growth of specific resistance of cakes in typical filtration. At the same time, SERS technology was introduced to detect trajectory of filtering particle with filtrate in different precoat, so as to determine the optimum particle size of filter aid, the thickness of precoat and the mass concentration of precoating suspension. And the solid content in filtrate can be controlled within 100 ppm. Precoating filtration separation technology has been successfully developed through the combination of laboratory experiment and pilot test, and this technology was applied to project of catalyst recovery in Methanol-to-olefin. |
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