Preparation And Electric Adsorption Modification Of Activated Carbon Made From Chili Straw

Chili straw resources in China is quite plentiful,and rich source of carbon and low ash content,so it has the potential to produce high quality performance of activated carbon.The rational use of pepper straw,find new ways to not only for its disposal,improve the added value of subsidiary agricultural products,but also find cheap available raw materials for the preparation of activated carbon,to achieve the resource utilization of pepper straw.Based on pepper straw as raw material to prepare the activated carbon,this paper studies the preparation craft of the activated carbon.Using SEM?BET?FTIR?XRD characterizated its surface physicochemical properties,and tests the electrochemical performance of the activated carbon modified by TiO₂.In the process of the preparation of activated carbon,the first is the experiment and analysis to determine the carbonization temperature range is 400⁵00?,selected through orthogonal test the optimal carbonization conditions:the corbomization temperature 400?,50 min coking time,heating rate of 5?/min.Carbonized material surface and internal parts formed tiny pore of non-uniform,the average pore size of200.225nm,carbonized material is illustrated in a certain amount of medium and large pores,and need to be further pore-forming further activation process.The experiment analysis of the activation part was followed.The limiting value of the activation temperature was 650⁸50?for the mixed sample of KOH and the carbonized material.Orthogonal erperiment and single-factor experiment were used to determine the optimal activation conditions:the activation temperature of 800?,the activation time of 100min,the impregnation ratio of 3,dipping time 20h.Under this condition,the iodine adsorption value of 1348.44mg/g,methylene blue adsorption value of 19.0mL/0.1g.The carbon content of the prepared activated carbon increased of 34.72%than raw materials,and the BET surface area was 1761.16m²/g,the average pore size of 3.15nm.SEM showed that the activated carbon surface is smooth,appear uneven and developed honeycomb pore structure.XRD showed that activated carbon of the diffraction angle increased,d₀₀₂02 and L_c all induced.The results of FTIR were that the surface groups of the activated carbon from pepper straw might obtain carboxyl,alcohol,hydroxyl,amino,ether and other groups.After the activated carbon material from pepper straw loaded with TiO₂,the carbon skelecton structure surface is rough,not smooth,also appears some particles reunion phenomenon,specific surface area decreases to 1761.16m²/g to 1284.87m²/g,the total volume and pore volume decrease.FTIR and XRD analysis show that the materilas after loaded TiO_2,the surface of the materials is-TiO?-CTi?-C-Ti-O key hydrophilic groups,Ti existed in anatase type crystal,improving electrode performance.After TiO₂ modified the activated carbon,the specific capacitance increased,the adsorption capacity decreased and the electrochemical performance enhanced.The above results indicate that pepper straw can prepare the good adsorption properties of the activated carbon materials.