Constructions Of Multifunctional Fluorescent Probes And The Detections And Removals Of Mercury(Ⅱ)and Palladium(Ⅱ)ions

Heavy metal ions cause serious harm to the human central nervous system and may cause diseases such as rickets and cancer.Therefore,the detection and removal of heavy metal ions in the environment is of great significance.The general methods for detecting heavy metal ions include atomic absorption spectroscopy（ABS）,inductively coupled plasma emission spectroscopy（ICP-OES）,inductively coupled plasma-mass spectrometry（ICP-MS）,atomic fluorescence spectroscopy（AFS）,molecular fluorescence spectroscopy（FL）,and so on.Among them,the fluorescent probe method is popular due to its high sensitivity,simple operation,and low detection cost.Fluorescent probes for detecting heavy metal ions can achieve detection purposes by coordination or reaction with the heavy metal ions to change the fluorescent signal of the probe.Compared to the coordination type fluorescent probe,the reactive type probe has higher selectivity to metal ions.At present,the fluorscent probes with different frameworks for detecting metal ions were designed and developed,however,most of them can only detect heavy metal ions,but cannot remove them.In view of this,in this thesis,two novel reactive fluorescent probes were designed and coated on the substrate to construct a solid fluorescent probe,which was used to detect and removal of Hg²⁺and Pd²⁺ions.The main content was presented as follows:1.In this thesis,a novel fluorescent probe named CA-S with coumarin framework was designed and coated on the chitosan non-woven fabric.The prepared actived fabric presents an excellent selectivity for Hg²⁺ion with a detection limit of 1.26×10^-7M,and can efficiently remove Hg²⁺ion in the water.¹HNM and HRMS analysis and DFT calculations reveal that Hg²⁺ion promotes the hydrolysis of CA-S to produce compund 2,which has the character of ACQ.The chitosan unit acts as a spacer and prevents theπ-πstacking of compound 2.As a result,the green fluorescence was excited.In addition,the acitved fabric presents a large adsorption capacity for Hg²⁺(over 1000 mg.g^-1)and a short adsorption equilibrium time（within 10 min）.The actived fabric was used for the detection and removal of Hg²⁺of industrial wastewater.The removal rate is larger than 99%,and the residual concentration of Hg²⁺is less than 0.03 ppm,which is lower than the national emission standard of 0.05 ppm.2.In this thesis,a high sensitivity open-type fluorescent sensor TPM-B based on the excited state intramolecular proton transfer（ESIPT）mechanism was designed and to detect palladium ions(Pd²⁺)in the water.The probe is an optimized alkyne derivative of 2-（benzothiazol-2-yl）phenol,which has a fluorescence response only to Pd²⁺ion.The changes on fluorescence is from no to green through ESIPT mechanism.The silica gel plate substrate treated with TPM-B probe can detect Pd²⁺in the water and the detection limit is 9.70×10^-8M.The geometries of TPM-B and TPM on the ground state（S₀）and the first singlet excited state（S₁）were optimized by DFT method.The transformation of TPM from alcohol style to ketone style through ESIPT mechanism was studied.A perfact agreement between the calculated and experimental fluorescence spectrum proves its validity.