Preparation Of Superabsorbent Poly (Acrylic Acid)/Graphene Oxide Composite Hydrogel And The Study Of Its Adsorption To Dye

Nowadays,the organic dye pollution caused by chemical industry and other dyes application industry has become a global problem urgently need to be solved.Adsorption method is one of the most effective ways to dispose dye wastewater.However,there are defects of conventional adsorption materials.Hydrogels have good swelling property,biocompatibility,non-toxic,easy to recycle,biodegradable etc.,recent years,hydrogels are widely developed and applied in the field of environmental protection.Hydrogels relate to dye wastewater treatment have been reported,but,the reported hydrogels have some shortcomings,such as craft complex,weak adsorption ability,difficult to repeated use etc.,which greatly limit its application in dye wastewater treatment.This thesis focuses on the traditional dye adsorption of poly?acrylic acid?hydrogel existing defects of low adsorption capacity,poor mechanical properties and difficult to reuse.Using graphene oxide?GO?to reinforce poly?acrylic acid?to form composite hydrogel,with excellent mechanical properties and super strong adsorption ability of GO to effectively improve the mechanical properties of poly?acrylic acid?hydrogel and also gives the composite hydrogel super moisture absorption ability and dye adsorption ability.Meanwhile,using modified Nano titanium dioxide?TiO₂?with GO,acrylic acid to form composite hydrogel,with the three-dimensional network structure of the hydrogel to fix TiO₂,which solves the problem of TiO₂ is difficult to recycle,and with the help of GO to enhance the dye degradation ability of TiO₂.The main research contents of this paper are as follows:?1?Using the improved Hummers method,by concentrated sulfuric acid-potassium permanganate oxidation system to intercalate and oxidate graphite and ultrasonic stripping graphite oxide to prepare graphene oxide.Then,through physical modification of graphene oxide-amphiphilic block copolymer Pluronic F127?PF?adds to graphene oxide solution and by the hydrophobic effect attaches on the surface of graphene oxide,which is improving the stability and dispersion of graphene oxide in various environment and foundation for preparation of uniformity hydrogel.?2?At room temperature,mixing graphene oxide solution and acrylic acid solution,with potassium persulfate triggering in-situ polymerization to form graphene oxide/poly?acrylic acid?composite hydrogel.We take a scanning electron microscope?SEM?for composite hydrogel,the mesh of composite hydrogel is greater which benefits for water and dye adsorption and also indicates that graphene oxide have been good enough composite with poly?acrylic acid?.Then,we have the composite hydrogel do mechanics tensile test and compression test,the results show that the addition of graphene oxide improved the mechanical properties of poly?acrylic acid?hydrogel,making composite hydrogel is more advantageous to apply in complex environment.Moreover,the swelling performance of the composite hydrogel was tested,results show that composite hydrogel has super absorbent for water?the maximum swelling rate of composite hydrogel up to 490 g/g and pure poly?acrylic acid?hydrogel is only 68 g/g?.Finally,we do the dye adsorption test with hydrogel,the results show that composite hydrogels have the ability of selective adsorption of cationic dyes,and the equilibrium absorption capacity of composite hydrogels of adsorbing for methylene blue is as high as 1600 mg/g?pure poly?acrylic acid?hydrogel is 770 mg/g?.We also do dye adsorption-desorption repetitive experiment,the results show that composite hydrogels have the reuse ability.At the same time,we respectively explore the different GO content and PF content effect on composite hydrogels.?3?The PFDA was synthesized by the ester reaction at both ends of the PF,and the PFDA was used to replace the PF to modify the graphene oxide,with the modification grapheme oxide to composite with poly?acrylic acid?forming hydrogel.The effects of PFDA on the properties of the hydrogels were investigated by mechanical tensile and compression tests,swelling test,dye adsorption test,and dye adsorption-desorption test.?4?Nano TiO₂ was modified with silane coupling agent KH-570.Then,compositing the modified TiO₂ with graphene oxide and poly?acrylic acid?to form composite hydrogel.Using composite hydrogel to do dye adsorption and photocatalytic?under UV irradiate?experiments and exploring the modification of TiO₂ content on the influence of the composite hydrogels degradation ability to dye.