Investigation For The Separation/Enrichment And Mechanism Of Inorganic Environmental Hormones By Solid Phase Extraction On Titanium Whisker

Environmental hormones,also known as environmental endocrine disrupters,are harmful chemical substances released into environment because of human activities and can disrupt biological endocrine system. Environmental hormones can be divided into organic environmental hormones and inorganic environmental hormones.Inorganic environmental hormones(IEHs) mainly include cadmium,lead,mercury,etc.Owing to restriction of selectivity and influence of samples,inorganic environmental hormones cannot be analyzed directly with equipment.Therefore, separation/enrichment of inorganic environmental hormones from samples is very important.Solid-phase extraction has gained attention of many analytic researchers for its several advantages,including operating simply, high pre-concentration factor,rapid phase separation,and the ability of combining with different detection techniques.Titanate whisker materials have some good performances such as specific strength,modulus,dimensional stability,etc.It has widely application not only on photoelectric materials,but also on adsorption, separation and other fields.In recent years,Molecular Imprinting Technique(MIT) has been developed as the new technology for the preparation of polymer with specific ability for identification of targeted compound.In this work,IEHs were pre-concentration/separation by using whisker titanium/modified whisker titanium/surface ion imprinted titanate polymer as solid-phase extractant.The work mainly included the following items:(1) Study on the pre-concentration/separation of IEHs using titanate whisker as solid-phase extractantâ…°.The absorption behaviors of K₂Ti₄O₉ towards Cd(â…¡),Pb(â…¡), Ni(â…¡) using FAAS as sensitive detector was studied.Under optimum conditions,the possiblility of absorption mechanism was investigated and applied to the speciation analysis of Cd(â…¡),Pb(â…¡),Ni(â…¡) in environmental water samples and the detection limits were 2.5μg·L^-1 with relative standard deviation(RSD) of 2.6%for Cd,3.6μg·L^-1with RSD of 3.1%for Pb and 56μg·L^-1 with RSD of 2.9%for Ni,respectively.It was found that the proposed method used in the paper had many advantages such as good stability and good performance of absorption and desorption.â…±.A new method was proposed for the separation/enrichment of Co(â…¡),Ni(â…¡),Cr(â…¢) using K₂Ti₆O₁₃ as solid-phase extractant and ICP-AES as sensitive detector.The major factors influencing the process of separation and enrichment were investigated,including the interference of co-existing ions and the possible sorption mechanism.Under optimum conditions,the detection limits were 9.2μg·L^-1 with relative standard deviation(RSD) of 0.98%for Co,5.3μg·L^-1 with RSD of 0.75%for Ni and 8.9μg·L^-1 with RSD of 0.87%for Cr,respectively.It was found that the proposed method used in the article had many advantages including good stability and good performance of absorption and desorption.The result showed that the method was suit for the analysis of industrial waste water samples.(2) Study on the pre-concentration/separation of IEHs using surface modification -titanate whisker as solid-phase extractantâ…°.The new solid-phase extractant(KH-560/K₂Ti₄O₉) was prepared by using sol-gel method with KH-560 as the surface modification agent, K₂Ti₄O₉ as the carrier.KH-560/K₂Ti₄O₉ was characterized by using SEM, FI-IR,XRD.The absorption behavior of KH-560/K₂Ti₄O₉ towards Pb using FAAS as sensitive detector was studied.Under optimum conditions, the selectivity for Pb(â…¡) of KH-560/K₂Ti₄O₉ was also discussed in mixed aqueous solution.The detection limit was 2.5μg·L^-1 with relative standard deviation(RSD) of 2.6%for Pb(â…¡),respectively.It was found that the surface modification of K₂Ti₄O₉ using KH-560 could effectively increase the hydrophobic properties.â…±.In this paper,the C₁₃H₁₂N₄S/K₂Ti₆O₁₃ as solid sorbent was prepared by using impregnation method,and characterized by using SEM,FI-IR.Effects of adsorption acidity,sorbent dosage and resting time on adsorption rate to Cd(â…¡),Pb(â…¡) on C₁₃H₁₂N₄S/K₂Ti₆O₁₃ were investigated by ICP-AES.Under optimum conditions,the method was applied to the determination of real water samples,and the detection limits were 1.2μg·L^-1,1.6μg·L^-1 for Cd(â…¡) and Pb(â…¡),respectively.The results indicated that the C₁₃H₁₂N₄S/K₂Ti₆O₁₃ can adsorb some ions like Cd(â…¡) and Pb(â…¡).(3) Study on the pre-concentration/separation of IEHs using surface ion-imprinted titanate polymer as solid-phase extractantâ…°.The Pb(â…¡) ion imprinted polymer particles were prepared by surface molecular imprinting technique and sol-gel process in acetic acid solution,with Pb(â…¡) ion as the template,chitosan(CTS) as the functional monomer,Na₂Ti₃O₇ as the carder,and KH-560 as the crosslinking agent. The ion-imprinted polymer particles were characterized by FT-IR,XRD, SEM and TEM.Effects of adsorption acidity,sorbent dosage and resting time on adsorption rate were investigated by FAAS.Selectivity of the prepared polymer for Pb(â…¡) ions was also discussed in mixed aqueous solution.Adsorption capacity of Pb(â…¡)-â…¡P was compared with that of non-imprinted polymer(NIP).The imprint and adsorption mechanism were also put forward.The results indicated that Pb(â…¡)-â…¡P exhibited high selectivity for Pb(â…¡) ions and hydrophobic properties.â…±.Ni(â…¡) ion imprinted polymer(Ni(â…¡)-â…¡P) particles was prepared by the combination of surface molecular imprinting technique and sol-gel process in acetic acid solution,with Ni(â…¡) ion as a template,CTS as functional monomer,and KH-560 as the cross-linker.The configuration of Ni(â…¡) ion imprinted polymer and its materials were characterized by FT-IR spectra,UV-spectra,SEM,TEM and XRD.The optimal adsorption conditions,such as acidity,resting time,amount of sorbent etc,were investigated by FAAS.Selectivity of the prepared Ni(â…¡) ion imprinted polymer in dilute aqueous solution was examined by ICP-AES.The mixed solution was consisted of Cd(â…¡),Co(â…¡),Cu(â…¡),Hg(â…¡),Mn(â…¡),Cu(â…¡), Pb(â…¡) and Zn(â…¡) ions.Finally,the imprint mechanism of Ni(â…¡) ions on Ni(â…¡) ion imprinted polymer was discussed in detail.The adsorption capacity of Ni(â…¡) ion imprinted and non-imprinted polymer particles were discussed,respectively.Ni(â…¡) ion imprinted polymer exhibited higher selectivity for Ni(â…¡) ions than non-imprinted polymer in the mixed aqueous solution.The results indicated that the pre-concentration/separation of inorganic environmental hormones by titanate whisker has the disadvantage of poor selectivity.Titanate whisker was modified by surface ion imprinting technique and sol-gel process.The surface ion imprinted titanate polymer was used as the solid-phase extraction materials to pre-separation/ enrichment inorganic environmental hormone with high selectivity.The adsorption behavior and mechanism were also studied.A new method for determination of trace Inorganic Environmental Hormones in environmental samples was established by combination of the SPE on surface ion imprinted titanate polymer and equipment directly through detection techniques.