Preparation Of Cobalt Ferrite/Sulfonated Graphene And Study On Its Adsorption Performance For Dyes

Graphene-based novel adsorbents have attracted much attention of many researchers in the field of adsorption.However,their widespread application is still severely restricted by the lack of good dispersity,anti-agglomeration property and recyclability.In this study,strong magnetic nanocomposite cobalt ferrite/sulfonated graphene（CoFe₂O₄/GS） was prepared by solvothermal method.Firstly,GS was prepared by diazotization using graphene oxide（GO） as raw material.And then GS combined with Co²⁺ and Fe³⁺ ions with a following recution process.The effects of solvothermal synthesis conditions（solvent,temperature） on morphology and dispersion in water of CoFe₂O₄/GS were investigated.The results showed that the optimum synthesis condition was obtained as followed:a mixed solvent(V_ethanediol:V_water=3:1),150℃ temperature and 10 h reaction time.The as-synthesised CoFe₂O₄/GS was used as absorbent for organic dyes solutions.The adsorption performance of CoFe₂O₄/GS was conducted on four different cationic and anionic dyes:methylene blue（MB）,methyl orange（MO）,rhodamine B（RhB） and methyl red（MR）.The results showed that CoFe₂O₄/GS has good removal effect on MO and RhB with removal rate of 99.5%and 99.8%respectively.The effects of adsorption conditions on anionic dyes MO and cationic dyes Rh B adsorption over CoFe₂O₄/GS were also investigated.The results showed that the adsorption capacity for orgnic dyes was influenced by absorbents,adsorbent dosage,p H value,and contact time.In addition,the adsorptions of two dyes are spontaneous endothermic processes,which conformed to Langmuir isotherm and quasi-second-order kinetic model.The good adsorption performance of organic dyes was also investigated by comparing the microstructures of CoFe₂O₄/GS,GO and GS.Studies revealed that the main adsorption mechanisms of MO and RhB onto CoFe₂O₄/GS includes electrostatic andπ-πinteractions.