Design And Synthesis Of Porous Cobalt-based Sulfides And Their Adsorption Properties

With the progress of society and the development of industry,water pollution caused by organic dyes and heavy metal ions is becoming more and more serious,especially heavy metal ions such as lead and chromium,which greatly threaten human health.How to effectively remove organic dyes and heavy metal ions from wastewater has become one of the most significant and urgent to be solved problem facing humans.Although the traditional wastewater treatment methods have some effect,its shortcomings,such as high energy consumption,low treatment efficiency and easy to cause secondary pollution,greatly limit its further development and application.Adsorption,as an important means of organic dyes and heavy metal ions in wastewater treatment,has become an important research field in wastewater treatment due to its unique advantages.In this study,porous cobalt-based sulfide nanomaterials with large specific surface area,low density and unique pore size were synthesized.The adsorption of organic dyes and heavy metal ions in water by these nanomaterials was studied.The adsorption data were fitted and analyzed by Langmuir isotherm model.The experimental contents are as follows:1.Hollow CoS2 nanoparticles were synthesized by sulfurization and calcination using ZIF-67 as sacrificial template.The nanomaterials basically maintain the morphology of ZIF-67,and have larger specific surface area and smaller pore size.Furthermore,the adsorption properties of pollutants in water were studied.The CoS2 has superior performance for the removal of fluorescein sodium and Pb(II),and its maximum adsorption capacity is 289 and 758 mg/g,respectively.Meanwhile,CoS2 hollow polyhedron has a good recycling performance in the removal of fluorescein sodium and the removal efficiency remained 98%after the four cycles.2.The flower-like Co9S8 was synthesized by solvothermal method in one step The flower-like nanostructure consists of two-dimensional nanosheets with unique morphology,large specific surface area and weak ferromagnetism.It was found that the nanomaterials had superior adsorption performance for the removal of Congo Red from aqueous solution,and its maximum adsorption capacity was up to 2547 mg/g.We further studied the adsorption properties of the flower-like Co9S8 for Pb(?)in water,and its maximum adsorption capacity was 155 mg/g.In addition,the flower-like Co9S8 was used as electrode material for lithium ion batteries and its electrochemical performance was tested.When the current density is 0.1 A/g,the first discharge capacity can reach 711 mAh/g,and after 160 cycles,the discharge capacity can be maintained at 85 mAh/g.Due to their simple synthesis steps,high stability and excellent adsorption properties,the flower-like Co9S8 nanoparticles have more potential applications in water treatment,lithium batteries and other fields.