Preparation Of Chitosan-based PLA Water Treatment Reactorby FDM And Preliminary Study On Its Adsorption Mechanism

Due to the defects and deficiencies of the fused deposition molding(FDM)technology itself,its development has encountered obstacles.Today,FDM technology needs to develop strengths and avoid weaknesses,give full play to its individual characteristics,and realize the functionalization of FDM.The full functionalization of raw materials contributes to the many potential practical applications of FDM technology development.In this paper,PLA was selected as the matrix material of FDM,PBAT was used as the toughening modifier,and chitosan was added to functionally modify the material.The properties of the blend system were studied and the removal properties of Cr(VI)ions were investigated.Firstly,three kinds of chitosan with different viscosity grades were selected and melt blended with PLA and PBAT resin.The effects of chitosan viscosity and content on the microstructure and mechanical properties of the composite system were studied,and the composite wire was prepared for melting.Deposition molding.The results show that the addition of chitosan will reduce the viscosity of the composite,improve the fluidity of the material,and facilitate the melt processing.However,the addition of chitosan reduced the mechanical properties of the material.Comparing the properties of different viscosity systems,the experiment concluded that the surface of the medium viscosity system is rougher and exposes more particles,which is undoubtedly advantageous for adsorption.Therefore,a medium viscosity chitosan was selected as the material for subsequent experiments.Secondly,the dynamic rheological behavior and mechanical properties of the blend system under CS high filling system were studied.The preliminary adsorption of water-weight metal by adsorption of FDM was carried out.The results show that under the high filling system,the melt realizes the transition from “liquid-like” to “solid-like”,and the melt elasticity is enhanced,which is favorable for melt laying.At this time,the rheological percolation interval is 30-50 phr.In addition,the adsorption experiments of each formula were selected for the adsorption experiment,and the PLA/PBAT/CS(80/20/50,wt%)system was found to have the best adsorption effect.Finally,PLA/PBAT/CS(80/20/50,wt%)composites were selected to prepare a spiral 24-sided solid structure by fused deposition,which was used as a water treatment reactor for adsorption of Cr(VI)in water.The adsorption-like mechanism is discussed in the theoretical model of adsorption.The results show that:(1)When the solution pH=2,the water treatment reactor has the largest removal rate of Cr(VI),reaching 89%;(2)By fitting the adsorption kinetics model,the adsorption rate is mainly affected by the particles.Diffusion and liquid membrane diffusion are jointly controlled;(3)adsorption isotherm experiments show that the Freundlich isotherm adsorption model can better describe the adsorption process(R2>0.98);(4)adsorption thermodynamics show that the adsorption of Cr(VI)by the water treatment reactor is a Spontaneous endothermic reaction.