Preparation And Properties Of Cu(?) Imprinted Chitosan/Sodium Alginate Hybrid Adsorbent Microspheres

With the development of industry,heavy metal pollution in water has become a very serious problem.Water treatment has become the focus of env ironmental protection.Sodium alginate(SA)and chitosan(CTS)are both natu rat polymers,which have the advantages of wide source,simple and easy to obtain,regeneration,highly degradation,etc.,and have good adsorption properti es for heavy metal ions.The CTS is rich in amino groups,and there are a lar ge number of carboxyl groups on the SA.In this paper,using SA and CTS as the substrate,combined with ion-imprinting technology and step-by-step cross-linking method,the Cu2+ chitosan/Sodium alginate imprinted hybrid adsorbent microspheres with good adsorption capacity,selective and stability were prep ared.Using Cu2+as a template,a stepwise cross-linking by 37%formaldehyde(FA)and epichlorohydrin(ECH)was used to prepare the chitosan/calcium alginate hybrid imprinted microspheres(CTS-SA/IIP).The single factor test method was used to optimize the cross-linking process conditions for FA and ECH.The CTS-SA/IIP hybrid imprinted microspheres prepared under the optimal conditions had a Cu2+adsorption of 105.14 mg/g and a swelling degree of 1289.26%in water.The separation for Cu2+/Zn2+4.60 and Cu2+/Cd2+ were 2.01 respectively,and the imprinting factor was 1.42.The Cu2+ adsorption process of the imprinted microspheres conformd to the pseudo-second-order kinetics model and the Langmuir isotherm model.The adsorption thermodynamics indicated that the adsorption of Cu2+was a spontaneous endothermic process.Repeated performance test studies found that the imprinted microspheres have good repeatability.SEM showed cross-linking effect on the surface morphology of imprinted microspheres.FTIR indicated that FA and ECH mainly act on the hydroxyl and amino groups of the microspheres.On the basis of the preparation of CTS-SA/IIP hybrid imprinted microspheres,the participation of calcium ions was removed,and the copper ion was used as both curing agent and template for SA.To prepare the copper chitosan-alginate hybrid imprinted microspheres(CTS-SA/Cu)with higher selectivity.Orthogonal test was used to optimize the preparation process.Under the optimal conditions,the CTS-SA/Cu hybrid imprinted microspheres had a Cu2+ adsorption of 103.5 mg/g.The separation for Cue+/Zn2+were 6.74,Cu2+/Cd2+were 3.03 and Cue+/Pb2+ were 1.22 respectively.The Cu2+ adsorption process of the imprinted microspheres conformd to the pseudo-second-order kinetics model and the Langmuir isotherm model.The adsorption thermodynamics indicated that the adsorbed Cu2+ is a spontaneous endothermic process.SEM showed that the microspheres obtained with the copper ion as a curing agent had more surface wrinkles.F TIR indicated that the cross-linking of Cu2+mainly actd on the hydroxyl and carboxyl groups of SA.The dynamic adsorption experiments of CTS-SA/Cu hybrid imprinted microspheres were investigated-The dynamic adsorption of Cu2+ in aqueous solution by the adsorbent reached 47.75mg/g.