Preparation Of Metal Organic Framework For The Detection And Adsorption Of Gold/Aniline/Iodine

Water is the source of life,water pollution seriously threatens the survival and safety of life,hindering and restricting the further development of economy and society.Gold ions,radioactive iodine and aniline are common pollutants in water.Their highly sensitive detection and effective removal are of great significance to human health and social sustainable development.Metal-organic framework（MOF）,with regular pore structure,excellent stability,high crystallinity and designability,has great potential in the detection and removal of contaminants,such as gold ions,aniline and radioactive iodine,and becoming a research focus of environmental analytical chemistry.This paper mainly focuses on the preparation of novel metal-organic framework materials and researches their interaction mechanism with gold ions,aniline and radioactive iodine,building an analytical method for gold ions and aniline as well as a highly efficient strategyfor iodine capture,mainly including the following contents:1.An analytical method for the efficient design of a fluorescence probe of detecting Au（III）ion is proposed based on a 3D terbium-based metal-organic framework.Firstly,N,N’-di（3,5-dicarboxybenzeneyl）-1,4,5,8-naphthalene diimide（H₄BINDI）was synthesized by condensation reaction of 1,4,5,8-naphthalenic anhydride with 5-amino-phthalic acid,then the mixture of H₄BINDI and Tb³⁺was reacted by solvothermal method,and successfully preparing a three-dimensional metal-organic framework named as Tb-NDI.Due to the excitation spectrum of Tb-NDI overlaps greatly with the absorption spectrum of Au（III）ion,a novel Tb-NDI-based fluorescence“turn-off”sensor was constructed for Au（III）ion determination based on the effective internal filter effect（IFE）between Au（III）ion and Tb-NDI,the detection limit is as low as 32 n M.Moreover,Tb-NDI was effectively applied in detecting Au（III）ions with hardly interference in the simulated electron waste liquid.Owing to the strong IFE between Au（III）ions and Tb-NDI,Tb-NDI shows highly sensitive and selective for Au（III）ions determination,exhibiting better performance than carbon dots,small molecule probes and graphene oxide probes.2.An analytical method for the efficient design of a fluorescence probe of detecting aniline is constructed based on a 2D cadmium-based metal-organic framework.Firstly,a naphthalimide derivative,named as HNI,was successfully synthesized by condensation reaction of 1,8-naphthalenic anhydride with 5-aminicotinic acid.HNI exhibited aggregation-induced emission（AIE）on the basis of the restriction of intramolecular rotation（RIR）mechanism.Then the mixture of HNI and Cd²⁺was reacted by solvothermal method,successfully preparing a two-dimensional metal-organic framework with strong fluorescence as well as excellent thermal and chemical stability,named as Cd-NI.Owing to the large number of lone electrons???π、C-H???πand C-H???O hydrogen bond interactions in the crystal structure,the neighboring layers will slide slightly and a certain extent of compression within layers triggered by external force.Such subtle molecular motions result in the dramatic conversion from the nonradiative state to the radiative state,which caused Cd-NI an off-to-on luminescent switching.Due to the HOMO value of electronic-rich aniline molecules is much higher than that of electronic-deficient Cd-NI,a novel Cd-NI-based fluorescence“turn-off”sensor was constructed for aniline determination based on the strong photoinduced electron transfer（PET）between Cd-NI and aniline,the detection limit for aniline is 60μM.Cd-NI shows ultra-high stability and excellent selectivity for aniline owing to the large number of lone electrons…π、C-H…πand C-H…O hydrogen bond interactions in the crystal structure and the strong PET effect between Cd-NI and aniline,having better performance than many previously reported fluorescence probes such as polymers,covalent organic frameworks.Thus,Cd-NI is expected to be used for the detection of aniline in harsh practical environment.3.A strategy for the efficient design of a radioactive iodine uptake adsorbent is proposed based on a 2D cobalt-based metal-organic framework material.Firstly,a mixture of 1,3,5-triimidazolyl benzene and Co²⁺was reacted by solvothermal method,successfully preparing a two-dimensional metal-organic framework,named as Co-tib.Co-tib shows excellent thermal stability and chemical stability.Owing to the open one-dimensional porous channels and a large number of imidazolium nitrogen groups distributed in the pore wall in the crystal structure of Co-tib,the charge transfer interaction and strong electrostatic interaction occur between Co-tib and iodine.Thus,an effective strategy for iodine capture was established based on Co-tib.Co-tib shows ultrahigh iodine adsorption,which reaches up to 1.15 g g^-1in vapor and 250.7 mg g^-1in solution.Furthermore,Co-tib can not release iodine until the temperature rise to 200oC,indicating the strong retention effect of Co-tib for iodine vapor.Compared with many previously reported solid sorbents,Co-tib shows better performance for iodine capture.