Study On Preparation Of Hyperbranched Polyamide Modified Sodium Alginate Microspheres And Its Adsorption Properties For Sb(?) In Printing And Dyeing Wastewater

With the wide application of polyester fabrics,the release of residual antimony catalyst in polyester fibre during dyeing and finishing process reaches to an unacceptable high level and threatens the water safety and human health.Therefore,it is urgent to develop treatment methods for Sb???with high efficiency and low cost.The adsorption technique has been recognized as the suitable approach for Sb???heavy metal removal in industrial applications.Particularly,the adsorbent is a key component to achieve high-efficiency adsorption.For this purpose,a hyperbranched polyamide modified sodium alginate?HA@SA?microsphere adsorbent was designed and prepared for the enhanced adsorption of antimony from a high Sb???concentration effluent.On this basis,further combination with ion imprinting technology,the Sb???imprinted sodium alginate?Sb???-SAIIP?microsphere adsorbent was fabricated to improve the selectivity of SA microspheres for Sb???removal from wastewater with low-concentration Sb???.The specific research contents and results are as follows:?1?Preparation of HA@SA microspheres and its adsorption performance of Sb???The SA microspheres were firstly fabricated with SA as substrate and CaCl₂ as cross-linking agent.Afterwards,the self-made hyperbranched polyamide?HA?was applied to modify the SA microspheres to prepare HA@SA microspheres.The effects of HA dosage,reaction temperature and reaction time on the adsorption properties of the prepared HA@SA microspheres were studied and the preparation condition of HA@SA microspheres was optimized.The structure of HA@SA microspheres before and after adsorption was characterized by FT-IR,SEM-EDS and XPS.Secondly,the effects of solution pH,adsorbent dosage,initial concentration of Sb???,adsorption temperature and adsorption time on the adsorption performance of HA@SA microspheres were studied by static batch adsorption experiments.The adsorption mechanism of HA@SA microspheres was investigated by adsorption kinetics,isotherms and thermodynamic studies.The effects of wastewater flow rate and initial concentration of Sb???on the adsorption performance of Sb???by HA@SA microspheres were investigated by dynamic column adsorption experiments.Finally,the reusability of HA@SA microspheres was investigated by adsorption-desorption experiments.The results showed that the optimum preparation condition of HA@SA microspheres was:the mass ratio of HA and SA was 1:2,reaction temperature was40?,reaction time was 1 h.The optimum pH for adsorption of Sb???by HA@SA microspheres was 5.0.The maximum adsorption capacity of HA@SA microspheres for Sb???adsorption was up to 186.92 mg/g,which was 1.95 times higher than that of SA microspheres?95.94 mg/g?.The adsorption process of Sb???accorded well with the pseudo-second-order kinetic model and the Langmuir isotherm model.It showed that the adsorption process was mainly ruled by homogeneous single-layer adsorption via chemical interaction.Besides,the adsorption of Sb???was exothermic and spontaneous.In dynamic column adsorption experiments,low flow rate and low Sb???concentration could achieve better adsorption performance.After 8 cycles of adsorption-desorption experiments,the adsorption capacity of Sb???on HA@SA microspheres still retained more than 90%of the original one.?2?Preparation of Sb???-SAIIP microspheres and its adsorption performance of Sb???In this part,the Sb???-SAIIP microspheres was prepared by ion-imprinting technique with HA@SA microspheres as base substrate,Sb???as a template ion and glutaraldehyde as cross-linking agent respectively,and applied for the deep treatment of low concentration heavy metals Sb???in complex waters.The effects of the amount of cross-linking agent,reaction temperature and reaction time on the selectivity of the prepared Sb???-SAIIP microspheres were studied and the preparation condition of Sb???-SAIIP microspheres was optimized.The adsorption behaviors of Sb???-SAIIP microspheres on Sb???were systematically studied.The reusability and selective stability of Sb???-SAIIP microspheres was investigated by adsorption-desorption experiments.The results showed that the optimal preparation condition for Sb???-SAIIP microspheres was as follows:the mass ratio of 2 wt%glutaraldehyde solution and SA was 1:1,the reaction temperature was 60?,and the reaction time was 2 h.The optimum pH for Sb???-SAIIP microspheres to adsorb Sb???was 5.0.The adsorption isotherms matched with the Langmuir model well.The maximum adsorption capacities of Sb???-SAIIP and nonionic imprinted hyperbranched polyamide modified sodium alginate?NIP?microspheres were 35.57and 23.39 mg/g,respectively.The adsorption kinetics accorded well with pseudo-second-order kinetic model and the adsorption was a spontaneous exothermic process.Selective adsorption studies showed that Sb???-SAIIP microspheres had better adsorption peformance and selectivity for Sb???.After 8 cycles of adsorption-desorption experiments,the adsorption capacity ofSb???on Sb???-SAIIP microspheres could still retain more than 85%than that of the original one,and the selectivity also kept stable.Studies showed that the adsorption performance to Sb???of SA microspheres was highly enhanced by the functionalization with HA.Therefore,HA@SA microsp-heres could be applied for the effective removal of Sb???from effluent with high Sb???concentration.Furthermore,the selectivity of SA microspheres was effectively improved by the fabrication of Sb???-SAIIP microspheres via ion imprinting techniq-ue.The Sb???-SAIIP microspheres could be used for the deep treatment of low concentration heavy metals Sb???in complex waters.