Preparation, Characterization And Electrochemical Performance Of Activated Carbon From Long-stalked Almond Shell

Amygdalus pedunculata(A.pedunculata)is a novel sand dune-stabilizing and oil-bearing plant with higher economic value and ecological benefits,which will be planted in northern region as a candidate for desert reclamation by the State Forestry Administration of the People's Republic of China.Amygdalus pedunculata shell(APS)occupies over 70%of AP fruit by weight.The quality of high carbon content and low ash makes APS an excellent raw material to prepare activated carbon.In this study,activated carbons were prepared from APS by three different activation methods and characterized for their adsorption and structural properties.Meanwhile,the application of activated carbon on electrical double-layer capacitor(EDLC)electrodes and their electrochemical performances were discussed.Researches in depth for APS not only benefit to enhance additional value of A.pedunculata,but also recycle waste materials and reduce the pollution.Moreover,it will provide theoretical basis and data support for the production and application of APS activated carbon.Main results were as follows:1.Based on Box-Behnken design of response surface methodology,the preparation condition of activated carbons from APS with zinc chloride activation was optimized.A 3-factor,3-level and 17-run BBD method was applied to statistically study the process variables.The optimum condition for preparation of activated carbon has been identified as follows;50%ZnCl2,120 min,and 600? leading to 48.8%yield,1448.32 mg/g iodine,280.26 mg/g methylene blue adsorption values and 1449.7 m2/g BET surface area.The prepared activated carbon was in line with National Standards of GB/T 13803.3-1999 and GB/T 13803.4-1999.2.PC was chosen as an activated agent for the preparation of APS activated carbon.The effect of weight ratio of PC and shell,activation temperature,and activation time on the yield,iodine adsorption value,and BET surface of activated carbon were analyzed.The optimum results were reached under 1.5 of PC/Shell weight ratio,900?,and 80 min leading to the yield of 11.9%,2231.07 mg/g iodine value,and 2402.4 m2/g BET surface area.According to SEM results,the internal of activated carbon showed loose sponge-like structure after PC activation.3.APS activated carbon was prepared by steam activation method.The effect of activation time on yield and BET surface area were studied under the activation temperature between 850? and 950 0C.The optimum condition was 10 g/h steam flow,900 ?,and 180 min leading to 7.3%yield and 1814.6 m2/g BET surface area of activated carbon.4.The application of APS activated carbon on EDLC electrodes was analyzed by cyclic voltammetry(CV)and galvanostatic charge/discharge tests.Activated carbons prepared by the three methods showed desirable capacitor behavior.EDLC electrodes exhibited higher specific capacitance from PC activation method,which is 214.00 F/g.