Preparation Of Functional S Doped Carbon Materials With Sodium Lignosulphonate And Study On Its Properties

Sulfur-doped carbon materials?S-C?were prepared by sodium lignosulfonate via template method.The structure,morphology,specific surface area of the prepared S-C were studied by the scanning electron microscopy?SEM?,X-ray diffraction?XRD?,transmission electron microscopy?TEM?and Nitrogen adsorption-desorption experiment?BET?.And the study on both electrochemical properties and adsorption properties were carried out as follows:Firstly,S-C was prepared by sol-gel method.Sodium lignosulfonate and silica were used as carbon source and silica as template.The structure of S-C was charaterized by XRD.The result indicated that the prepared S-C had a graphite structure.The surface morphology and element valence of S-C were analyzed by SEM,TEM and XPS,which give the evidence that S had doped in to our S-C.The effect of sintering temperature on the porous structure of the prepared S-C was also investigated.It was found that the specific surface area of S-C showed the trend of increase first and then decreased when the sintering temperature increased.Accorddingly,the total pore volume showed the same trend.The effect of activation conditions on S-C was also studied.The results indicated that the average pore size,pore volume and specific surface area increased when higher concetration of KOH was used.At the same time,the specific surface area reached at 1938 m²/g after the activation by KOH,which was 500%higher than the samples without activation.In addition,electrochemical properties of S-C were also carried out.The effects of the dosage of ethyl orthosilicate and activation were investigated.The results showed that the S-C without activation had the best electrochemical properties,and the specific capacitance reached 217.4 F/g.Secondly,porous S-C was prepared by hydrothermal method with silica.The effects of reaction temperatures?120 ^oC,140 ^oC,160 ^oC,180 ^oC?on the structure and properties of the prepared S-C were investigated.The structure of the prepared S-C was analyzed by XRD,indicating a graphite structure of our S-C.The specific surface area of S-C was evaluated by dye adsorption method.The result showed that S-C-120 had the largest specific surface area,reaching 560.57 m²/g.The cyclic voltammetry was applied to study the electrochemical properties test of our S-C.The results showed that S-C-120 had the best electrochemical properties with a specific capacitance of 80.7 F/g at a scanning speed of 1 mV/s.At the same time,adsorption performance of our S-C was also studied by Cd²⁺and methylene blue.Freundlich and Langmuir adsorption model were applied to describe the adsorption behaviors.The results showed the adsorption of Cd²⁺can be well described by Langmuir adsorption model.The correlation coefficient?R²?was>0.97.The maximum adsorption capacity of S-C-120 was 24.55 mg/g.The adsorption kinetics of methylene blue adsorption was fitted by quasi-second-order kinetics model.The fitted result of R² was more than 0.99,which gave the evidence that S-C-120 could be describe as the quasi-second-order kinetics model.The maximum adsorption capacity of methylene blue by S-C-120 was 9.96 mg/g.Finally,S-C was prepared by template of ZnO.ZnO was grown in situ in the solution of sodium lignosulfonate to form ZnO-lignin gel.The in-situ growth of ZnO was used as template to produce porous structure,and then ZnO was removed by acid etching to prepare S-C.The morphology of ZnO-lignosulfonate composites were characterized by SEM.The result showed that the particle of ZnO was almost spherical and the sizes are uniform.After removal of the template by acid etching,the resulting S-C exhibited a large number of pore structures,as evidenced by SEM.The structure of prepared S-C was analyzed by XRD,indicating that S-C had a graphite structure.The effects of the amount of sodium lignosulfonate and the sintering temperature on the structure of S-C were also investigated.The pore structure and specific surface area were analyzed by nitrogen adsorption-desorption experiment.The result showed that S-C-6 had a good pore structure with a maximum specific surface area about 295 m²/g.At the same time,the electrochemical properties of the prepared S-C were tested.S-C-6 has higher specific capacitance with 71.3 F/g.The adsorption properties of the prepared S-C material was tested,The results showed that S-C-6 has the best the adsorption capacity,which reached 9.87 mg/g.Quasi-second-order kinetics model was also applied to fit the adsorption data.The fitting results showed that the S-C-6 sample had the maximum adsorption amount of Q_m,2?9.99 mg/g?and the rate constant k₂?0.2452 g/mg/min?,respectively.This indicated that S-C-6 possessed the excellent adsorption properties and the fastest adsorption rate.