The Study Of Fluorescent Probe And Adsorption Of Heavy Metal Ions Based On Hyperbranched Poly(Amido Amine)

Dendrimers and hyperbranched polymers are dendritic polymers with low solution viscosity,low chain entanglements,low solution viscosity,low melt,high solubility.They have a lot of internal cavities and a large n?Mber of terminal groups that are easy to be chemically modified.Different from perfectly branched and monodisperse dendrimers which have ideally branched structures with the degree of branching?BD?of100%consisting of dendritic units and terminal units,hyperbranched polymers are composed of dendritic units,linear units and terminal units,and display a randomly branched structure with a lesser degree of branching?DB,generally 40%–60%?.Generally,step-by-step synthesis,purification,protection,and deprotection are needed for accessing dendrimers with controlled perfectly branched structures,leading to the tedious and complicated synthetic procedure of dendrimers that the tedious synthetic route is generally time-cons?Ming and cost-enhancing.The synthesis of hyperbranched polymers are often based on one-pot reactions,requiring essentially no further purification.Therefore,hyperbranched polymers are more convenient to large-scale industrial production,which are beneficial to practical application.As is known to all,the structure and composition of hyperbranched poly?amido amine?are similar to poly?amido amine?dendrimers,but the hyperbranched poly?amido amine?prepared by a simpler and more economical.The hyperbranched poly?amido amine?is cheap and fine and attracts people's widespread attention.In this dissertation,the applications of hyperbranched poly?amido amine?in fluorescent probe and adsorption of heavy metal ions were investgated.The research methods and results are described in detail as follows.1.Autofluorescent hyperbranched poly?amide amine??HPAMAM?as effective fluorescent probe for label-free detection of copper?II?ionsA label-free fluorescent probe based on autofluorescent HPAMAM for copper ions was designed.HPAMAM is a cationic polymer containing many amino groups,which could bind Cu²⁺ions to form cupric amine complexes,leading to a selective quenching of the fluorescence intensity of HPAMAM via inner filter effect.The fluorescence intensity of HPAMAM decreased with increasing concentration of Cu²⁺ions and the linear response ranged from 0.05 to 25?M,with the corresponding detection limit?3?/k?of 17.15 nM.What's more,the influence of other coexisting ions were investigated.The result indicated the HPAMAM fluorescent probe provided a simple,rapid,selective and sensitive fluorometric method for detecting Cu²⁺ions,which could be also applied for detection of Cu²⁺ions in real water samples.2.Hyperbranched Poly?amido amine?-copper ions system as fluorescent probe for sensitive and selective detection of cyanideThe amino groups at the surfaces of HPAMAM can selectively and sensitively capture Cu²⁺to form absorbent cupric amine,which can quench the fluorescence of HPAMAM through an inner filter effect.CN^-can combine strongly with Cu²⁺to[Cu?CN?_x]^n-species,preventing Cu²⁺from being captured by the amino groups of HPAMAM.As a result,Cu²⁺can't quench the fluorescence of HPAMAM in the presence of CN^-.In other words,CN^-can“turn on”the fluorescence signal of HPAMAM-Cu²⁺system,producing a“recovered”fluorescence signal.After optimizing experimental conditions,we demonstrated that this easy methodology could offer a simple method for detection of CN^-with a detection limit of 54 nM?3?/k?and a linear response range of 0.5 to 200?M.What's more,the influence of other coexisting ions were investigated.The result indicated the HPAMAM-Cu²⁺system as fluorescent probe provided a rapid,selective and sensitive fluorometric method for detecting CN^-ions.3.HPAMAM/ODex hydrogel synthesis and adsorption behavior study for heavy metal ions.We fabricated a kind of composite hydrogel by HPAMAM and ODex and applied to the adsorption and removal of heavy metal ions in wastewater.These amino groups of HPAMAM can be crosslinked by aldehyde groups on the ODex to fabricate hydrogel.The results of rheology measurements implied that it formed a stable hydrogel,The morphology of the HPAMAM/ODex hydrogel was analyzed by SEM.It was found that the hydrogel had three-dimensional network structure so that the specific surface area of the hydrogel had been effectively increased.Because HPAMAM/ODex hydrogel contains lots of amino groups and hydroxyl groups that can complex with metal ions,the adsorption performance of the HPAMAM/ODex hydrogel for Cu²⁺,Pb²⁺,Cd²⁺,and Ni²⁺were investigated.The HPAMAM/ODex hydrogel showed good adsorption ability for Cu²⁺,Pb²⁺,Cd²⁺,and Ni²⁺.The equilibri?M adsorption capacity of Cu²⁺,Pb²⁺,Cd²⁺,and Ni²⁺were 300.3,176.9,283.4,158.4 mg·g^-1,respectively.The results showed that the composite hydrogel could effectively adsorb heavy metal ions in wastewater.