The Preparation Of Cellulose-based Mg（OH）₂ Composites And Study Of Its Properties

In order to utilize cellulose with abundant resources and explore the application of cellulose/Mg(OH)2 composites in wastewater treatment and many other aspects,we prepared composites using Mg(OH)2 with cellulose and its derived carbon dots(CDs).The properties of different composites were discussed.The specific contents are as follows:Cellulose@Mg(OH)2 composites were prepared by hydrothermal synthesis of paper cellulose and Mg(OH)2.In order to investigate the effect of the amount of MgCl2 on the properties of composites,different quality MgCl2 was used to synthesize Mg(OH)2 in composites.The compositions of Cellulose@Mg(OH)2 composites were analyzed by XRD method.The results showed that the composites had high purity,and the growth of Mg(OH)2 along the c-axis was enhanced due to the presence of cellulose.The composites’morphology of cellulose coated with Mg(OH)2 was characterized by SEM and TEM,and found that the nano-sized Mg(OH)2 particles were closely arranged on the surface of cellulose fibers.The changes of functional groups in composites were found by FT-IR spectroscopic characterization.And XPS was used to analyze the binding energies of the elements in Cellulose@Mg(OH)2 composites.It was further confirmed that the composites were composed of cellulose and Mg(OH)2.The thermal stability of the composites was characterized by TG analysis.The results showed that the addition of Mg(OH)2 improves the theimal stability of the composites.In addition,the experimental results showed that Cellulose@Mg(OH)2 composites had good Cd2+ adsorption and flame retardancy.CNF/Mg(OH)2 composites were prepared by hydrothermal synthesis using cellulose nanofibers(CNF),which were obtained by hydrolysis of cotton fibers.The obtained composites had film-like smooth surface.The prepared CNF/Mg(OH)2 composites were characterized by XRD.It was found that CNF also enhanced the growth of Mg(OH)2 along the c-axis.It was observed by SEM and TEM that Mg(OH)2 was dispersed among CNF,but not on the CNF’s surface,The information of functional groups in composites was characterized by FT-IR spectra and through it the interaction between Mg(OH)2 and CNF was judged.In order to investigate the effect of the reaction system’s pH value on the properties,the CNF/Mg(OH)2 composites prepared under different pH conditions.Then composites were used for the adsorption of heavy metal Cd2+and the test of antimicrobial properties.The preparation conditions of the composites with the best properties were obtained.In order to make full use of cellulose resources,CDs obtained from CNF/Mg(OH)2 composites prepared in the previous chapter were re-compounded with Mg(OH)2 to prepare CDs/Mg(OH)2 composites.The compositions of CDs/Mg(OH)2 composites were characterized by XRD.The results showed that CDs was amorphous and Mg(OH)2 had good crystallinity,The FT-IR spectroscopy showed that Mg(OH)2 and CDs existed in composites.It was observed by SEM and TEM that the composites were consisted of non-uniform size CDs and flake Mg(OH)2.The fluorescence properties of the composites were characterized by PL spectroscopy.The results showed that the CDs/Mg(OH)2 composites had fluorescence properties from GDs.In order to investigate the effect of the amount of CDs on the properties of composites,CDs/Mg(OH)2 composites with different content of CDs were prepared by changing the volume of CDs solution during reaction.The adsorption of heavy metal Cd2+ and photocatalytic properties of CDs/Mg(OH)2 composites were tested.The results showed that CDs enhanced the adsorption and photocatalytic properties of the composite.