Preparation Of Casein Composites And Their Adsorption Properties For Methylene Blue

With the rapid development of economy,people get a better material life,but it also causes some environmental problems,one of which is water pollution caused by organic dyes.Dye is a kind of aromatic compounds,which is not easy to decompose.Excessive accumulation in water will cause great health hazards to people,so it is necessary to separate the dye from water.In modern society,there are many ways to treat wastewater,As a simple,efficient and economical method,adsorption is particularly attractive.The key of using adsorption method is to find an efficient and economical adsorption material.Graphene oxide(GO)has excellent characteristics such as high specific surface area,rich oxygen-containing groups and good dispersion.It can be easily combined with dissolved organic pollutants in water to remove them,and is widely used as a adsorption materials.Activated carbon(AC)has a large number of internal micropores,very high specific surface area and good chemical inertness.It has excellent adsorption capacity,and can effectively remove suspended particles,heavy metals and organic dyes from water.Casein(CA),as an important biopolymer,has the characteristics of non-toxicity and easy degradation in environment.It has a lot of hydrophilic functional groups and has good surface activity and stability,which is suitable for preparing hydrogels.Moreover,casein is easy to obtain and has good economy.The work of this paper is as follows:CA is used to package the GO and AC to prepare composite hydrogel in the presence of glutaraldehyde.After vacuum freeze drying,casein/graphene oxide composite material(CA/GO)and casein/activated carbon composites(CA/AC)were obtained,which can effectively can effectively improve their recycling efficiency The structure and morphology of CA/GO and CA/AC were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR),specific surface area analyzer(BET)and thermogravimetric analysis(TGA).It was found that the optimal mass fractions of GO and AC in the two materials were 8 wt% and 30 wt%,respectively.The effects of adsorbent dosage,p H value,contact time,initial methylene blue(MB)concentration and temperature on the adsorption capacity of the two materials were studied.The maximum adsorption capacities of CA/GO and CA/AC for MB were 403.23mg/g and 219.29 mg/g,respectively.The adsorption kinetics studies showed that the adsorption of MB by CA/GO and CA/AC followed the pseudo second order kinetic model.Thermodynamic studies showed that the adsorption of MB by CA/GO was exothermic and spontaneous,while the adsorption of MB by CA/AC was endothermic and spontaneous.