Trace Detection Technology Of Heavy Metal Ions In Integrated Circuit Cleaning Waste Water

With the rapid development of Chinese integrated circuit industry,the potential environmental pollution caused by this industry will become more and more concerned.If the heavy metal ions in IC cleaning wastes are not properly treated and discharged randomly,they will be enriched in the environment and bring many diseases to human body.Therefore,there is a need for a rapid and highly sensitive in-situ detection method to determine whether the heavy metal ions in waste water meet the discharge standards.In this thesis,we designed a trace-level heavy metal detection nanosensor based on surface-enhanced Raman scattering（SERS）technology to detect Fe³⁺and Cu²⁺in IC cleaning waste water,which broadens the application of SERS.The main results of this thesis are as follows.（1）The Lee-Meisel synthesis method was improved based on the reaction mechanism,and the silver nanoparticles（Ag NPs）were synthesized by using silver ammonia solution reacted with glucose instead of the conventional method,and the PVP@Ag NPs were prepared by using polyvinylpyrrolidone（PVP）as a protective agent,and the reaction principle of the improved method was analyzed.（2）In order to accurately obtain the optimal reaction time and improve the synthesis efficiency,a set of in-situ reaction detection system based on UV-vis spectrophotometer was designed in this paper,and the reaction process was indirectly determined by monitoring the absorbance.According to the monitoring results,the optimal reaction time of this paper will be reduced to 30 minutes,compared with the 6hours reaction time of the previous method of synthesizing silver nanoparticles,which significantly improves the synthesis efficiency of silver nanoparticles.（3）The thesis innovatively use phytate molecules as both protectors and Raman signal molecules to design a nanosensor IP6@Ag NPs for trace-level Fe³⁺detection,thus avoiding the secondary modification process of silver nanoparticles.The use of this method can effectively avoid the potential environmental pollution during the modification process and effectively improve the detection efficiency.The nanosensor has a low detection limit(LOD=0.1μmol·L^-1)and a wide linear detection range(0.5μmol·L^-1 to 500μmol·L^-1)for Fe³⁺.In addition,the nanosensor has good stability and the detection effect did not change within one month,and it was successfully applied to the detection of integrated circuit standard cleaning solution No.2（SC-2）.（4）Based on the property that Cu²⁺can selectively catalyze the oxidation of L-cysteine,a nanosensor L-Cys/R6G-IP6@Ag NPs was prepared for trace-level Cu²⁺detection by using rhodamine 6G and L-cysteine to modify IP6@Ag NPs.The linear detection range of this nanosensor was 1μmol·L^-1～1 mmol·L^-1,and the detection limit is 1μmol·L^-1,which is much lower than the national sanitary standard for domestic drinking water,and was also successfully applied to the detection of SC-2.