Construction Of Mineral Ultra-Thin Film Based On LB Technology And Its Application In Fluorescence Resonance Energy Transfer And Simple Measurement Of Flotation Kinetics

Langmuir-Blodgett(LB)technology is a tool that can realize the directional arrangement of amphiphilic molecules on the air-water interface and transfer the molecular film to the substrate.In this artical,two types of mineral ultra-thin films(LB hybrid films)are constructed by LB technology,including dye molecules-laponite and minerals(pyrite,dolomite,etc.)-flotation agent molecules,and the related scientific problems in fluorescence resonance energy transfer(FRET)and the simple determination of flotation kinetics were studied respectively.The LB hybrid film composed of fluorescein(FL)and rhodamine B(RhB)and laponite was constructed.By investigating the surface pressure-molecular area(π-A)isotherm,the UV-visible absorption of the hybrid film was studied.The characteristics of spectroscopy and photoluminescence spectroscopy were studied and it was found that there is no FRET phenomenon when the two types of dye molecules are in the solvent,indicating that the FRET of two types of molecules in the system can not happened.In the presence of clay laponite,both types of molecules can achieve adsorption and self-assembly on the clay sheet,and the intermolecular distance is shortened,which can achieve energy transfer with a FRET efficiency of 92%.Based on the measurement results of atomic force microscopy and contact angle,it is found that FL is the donor and RhB is the acceptor.The clay can make the distance between the two types of molecules closer,and increase the concentration of dye molecules,which changes the surface of the hydrophobicity of film and realizes high-efficiency FRET.The research results prove that the clay sheet has application in the fields of electronic optical devices such as biosensors and dye lasers.Aiming at the difficult problem of complex and rough mineral flotation kinetics determination process,this paper uses LB technology to construct a composite mineral(pyrite as the main phase,dolomite and quartz as impurities)-flotation reagent molecular film,which simulated the adsorption process of foam flotation and simplified the surface bubble adsorption to the plane adsorption of the air-water interface.By measuring the surface pressure-adsorption time(π-t)kinetic curve,the adsorption process of the Langmuir hybrid film at the air/water interface is simply determined.Kinetic and thermodynamic data,including flotation kinetic time constant(T1/e,32.0～139.0 s),molecular adsorption rate constant(k=0.0315～0.00718 s-1),reagent dosage parameter(distribution coefficient Kd=0.221-0.339),the free energy of adsorption(-ΔG,2.68～3.74 kJ·mol-1),which realizes the simple determination of the complex adsorption process in the flotation process.Compared with the results of micro-flotation experiments,the data is in good agreement.The method has the characteristics of high accuracy of measurement data,simple measurement process,and real-time monitoring.Therefore,this method promotes a precedent for the application of LB technology in foam flotation kinetics and thermodynamic measurement technology.