The Preparation And Characterization Of Ag (â… ) And Ni (â…¡) Ion Imprinted Chitosan Composite Functional Material

Silver and nickel plays an important role in industry and daily life. Therefore, theirrecycling has received considerable attention with the exhaustion of silver resources.The chitosan/triethanolamine （CTS/TEA） composites including Ag-imprintedCTS/TEA membrane （Ag-IICTM） and nickel ion imprinting magnetic particles（Ni（Ⅱ）-IICPMP） were prepared by using ion-imprinted technology, and were appliedfor the recovery of precious metals and removal of heavy metal pollutants fromindustrial waste water.A preparation method of silver ion imprinted CTS)/TEA membrane（Ag（Ⅰ）-IICTM）was proposed: crosslinker agent and silver salt were added into CTSsolution, then the solution was stirred to form homogeneous solution. After deaeration,the casting solution was coated on the glass, then dipped into TEA coagulation bath toachieve CTS/TEA/Ag （I） membrane. After Ag（I） was eluted，Ag（Ⅰ）-IICTM was obtained.The optimized condition of preparing Ag（Ⅰ）-IICTM:2.0%CTS,0.6%AgNO3,3.0%crosslinker,10.0%TEA, the concentration of eluant for10.0g·L^-1, and elution time for300min. FT-IR spectra showed that Ag（Ⅰ）-IICTM adsorbs Ag+by coordination action.SEM analysis showed compared with CTS/TEA/Ag（I） membrane, the surface ofAg（Ⅰ）-IICTM is clear rough, and homogeneous texture appears on the surface, and afteradsorbing Ag+, a cladding layer is formed. XRD results showed that TEA is moresuitable than NaOH as coagulation bath in preparing Ag（Ⅰ）-IICTM.The maximum adsorption capacity of Ag（Ⅰ）-IICTM for Ag（I） ions are505.05mg·g^-1. Kinetic models were used for interpreting data obtained from batch experiments,which shows that the whole adsorption processes for Ag（I） ions are according withsecond-order kinetic equation, Static equilibrium test show that the process ofadsorption is fitted to Langumir model. The study of selective adsorption and recycling indicates show that Ag（Ⅰ）-IICTM have good selectivity and durability.CTS/PVA/Ni（Ⅱ）s were prepared by blessing CTS, PVA, Ni（Ⅱ） andFe₃O₄.Ni（Ⅱ）-IICPMPs were obtained by eluting Ni（Ⅱ） from the CTS/PVA/Ni（Ⅱ） s. Theoptimized condition of preparing Ni（Ⅱ）-IICPMPs were CTS for2.0%（w）, PVA for1.5%（w）, Ni（NO3）2for1.0%（w）,Fe₃O₄for2.0%（w）, and NaOH for10g L^-1. FT-IRspectra indicate that the amino group and hydroxyl in CTS changed after addingFe₃O₄;SEM analysis imply that Ni（Ⅱ）-IICPMP shows obvious gap after eluting Ni （Ⅱ） ionand increase specific surface area; XRD patterns indicate that there are theFe₃O₄characteristic diffraction peaks, and the addition ofFe₃O₄results in the decrease of thecrystallinity. The adsorptive performances are investigated using the magnetic particlesfor Ni（Ⅱ）, and the results show that the maximum adsorption capacity ofNi（Ⅱ）-IICPMPs for Ni（Ⅱ） ions are558.66mg·g^-1. Static equilibrium test show that theprocess of adsorption is fitted to Langumir model. Kinetic models were used forinterpreting data obtained from batch experiments, which shows that the wholeadsorption processes for Ni（Ⅱ） ions are according with second-order kinetic equation,The study of repeating and selective adsorption indicates show that Ni（Ⅱ）-IICPMPhave good durability and selectivity for Ni（Ⅱ） ions, and recycling experiments showthat the magnetic performance of Ni（Ⅱ）-IICPMP did not weakened after using tentimes runs.