Photo-Assisted Preparation Of Ag/AgCl Nanoparticles And Its Application In Dye Degradation And Fluorescent Detection

Ag/AgCl nanoparticles are widely used in photocatalytic dyes degradation and antibacterial materials due to the presence of the surface plasmon resonance.The advantage of the degradation is that in addition to the superoxide radicals and photogenic holes,the chlorine atoms with super-oxidizing properties can act on the target together.At present,the preparation methods of Ag/AgCl nanoparticles are mainly precipitation method,chemical reduction method and photoreduction method,etc.These methods have the following problems in the preparation process:Firstly,large material loss in the preparation process and environmental pollution caused by residual reagent;Secondly,the Ag/AgCl nanoparticles prepared by the above method have the disadvantages of long time consumption and low degradation rate when they degrade target pollutants which seriously affects the photocatalytic efficiency.Thirdly,high-power xenon lamp is used as the light source during the degradation process,which has a small practical range.In view of the problems in the above methods,this study will be silver nitrate and chloride ions present as impurities in reverse osmosis water as raw materials,in situ preparation has good light catalytic Ag/AgCl nanoparticles under the power of 20 W and a wavelength of 395 nm uv light.It was also found that rhodamine 6G was degraded by REDOX reaction during the preparation of Ag/AgCl nanoparticles.In addition,the Ag/AgCl formation process was applied to the fluorescence quantitative analysis of silver ions in aqueous solution.This paper mainly includes the following three aspects:(1)Ag/AgCl nanoparticles were prepared with silver nitrate and Cl-in the form of impurities as raw material under the irradiation of 395 nm ultraviolet light source(20 W).Firstly,a comprehensive analysis of transmission electron microscope(TEM),dynamic light scattering(DLS),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and transmission electron microscopy-Mapping showed that spherical Ag/AgCl nanoparticles with a particle size distribution of 50-200 nm and good crystallization were successfully prepared in this paper.Secondly,UV-vis spectrum,fluorescence spectrum,high performance liquid chromatography(HPLC),mass spectrometry(MS)and nuclear magnetic resonance(1H-NMR)were used to comprehensively analyzed the spectral properties and degradation products.Comprehensive analysis to join in the process of preparation of Ag/AgCl nanoparticles can make its degradation rhodamine 6 g by more than 90%,the degradation method is applicable to a wide pH range(3.0?11.0)and the conjugate structure disappears after the degradation of rhodamine 6G.It is speculated that it may be degraded into small molecules such as carbon dioxide.Further research results shown that in addition to rhodamine 6G,the photo-assisted preparation process of Ag/AgCl nanoparticles have good degrdation ability for rhodamine B,luciferin,eosin Y,coumarin and other xanthon-based fluorescent dyes.(2)The first research in this paper found that rhodamine 6G can be used as a "Dual-Key-and-Lock" type fluorescent probe to specifically detect Ag+ in aqueous solution.Taking relative fluorescence intensity as the index of investigation and using single-factor optimization experiments to determine the appropriate working conditions for Rhodamine 6G as a "Dual-Key-and-Lock"type Ag+fluorescent probe:the molar concentration of rhodamine 6G is 1.0 ?M,the applicable pH range was 1.0?11.0 and the response time is 3.0 min at room temperature.The experimental results showed that within the range of silver ion concentration of 0?50 ?M,the fluorescence quenching degree of rhodamine 6G has a good linear relationship with the Ag+concentration.Rhodamine 6G as a"Dual-Key-and-Lock”type Ag+fluorescent probe has high detection sensitivity,convenient operation,wide range of pH application,high selectivity,good anti-interference and good practical application prospect.(3)Further research in this paper found that coumarin derivatives CMDM-Ag exhibited two fluorescence response modes to Ag+during photo-assisted Ag/AgCl preparation.Therefore,the performance of the compound CMDM-Ag as a "dual-channel" Ag+fluorescent probe was also investigated.The "dual-channel" fluorescence detection performance of the compound CMDM-Ag is reflected in the following two aspects:The fluorescence changes from green to blue instantly when the fluorescent probe solution is mixed with silver ions and chloride ions,other metal ions will not produce similar situation;After the solution was irradiated with UV light at 365 nm for 5.0 min,the fluorescence emission peak at 468 nm disappeared.Through optimizing the experimental conditions such as illumination time,different concentration ratios and different pH values,the suitable working conditions for CMDM-Ag as a "dual-channel" Ag+fluorescent probe were determined:In the range of pH 1?10,the molal concentration of CMDM-Ag was 1.0 ?mol,and the response time at room temperature was 5.0 min.The multichannel selective detection of Ag+ ion by the fluorescent probe is easy to operate,high sensitivity and weak interference from common co-existing ions.