Study On Preparation And Properties Of Cotton Fiber-based Self-bonding Activated Carbon

In this experiment,cotton fibers were used as raw materials,zinc chloride,potassium carbonate and zinc chloride-potassium carbonate were used as activators and molded activated carbon were prepared by pretreatment and pyrolysis at high temperature without binder.The effects of molding pressure,material ratio,type of activator,and activation temperature on the molding effect and adsorption capacity of the product were discussed in detail,and the optimum preparation conditions were obtained.The mechanism of activating agent was discussed preliminarily,and the following conclusions were obtained:?1?With zinc chloride as activator,the optimum preparation parameters were:activation temperature 600?,zinc material ratio 1:1.5,and forming pressure 10 MPa.The adsorption value of methylene blue of the product was437 mg/g and the strength 59%.SEM analysis results showed that there were still fibrous structures in the ACZ structure of the product,and there were a lot of gaps between the structures,which made the strength of the product low.There were vibration peaks of 1600 cm^-1 and 1450 cm^-11 aromatic rings in ACZ which formed in the activation stage made the products bond tightly,showing shrinkage on the macro level and further enhancing the strength of products.XRD analysis showed that there were diffraction peaks of aromatic middle carbon layer structure in ACZ structure,which were consistent with the results obtained by infrared spectroscopy.The specific surface area of ACZ was 1616m²/g and the micropore rate was as high as 78%,and the average pore size was1.9 nm,which indicated that the pore structure of products activated by zinc chloride was mainly microporous.?2?Potassium carbonate as activator,the optimum preparation parameters were activation temperature 800?,material ratio 1:5,and forming pressure 25MPa.The adsorption value of methylene blue was 330 mg/g.The results of SEM analysis showed that the pore structure of ACK was abundant and the pore wall was thin.The mesoporous rate of ACK was up to 17%,which was a kind of activated carbon material with high mesopores.The product ACKZ had dense internal structure and thicker pore wall,which indicated that zinc chloride and potassium carbonate acted together,and they can form a synergistic effect.Infrared analysis showed that there were 1600 cm^-1 and 1500 cm^-11 aromatic ring vibration peaks in ACKZ,which indicated that the addition of zinc chloride played a shrinking role in the activation stage,enhanced the internal structure of the product and enhanced its strength;XRD analysis showed that there were no specific diffraction peaks in both products,amorphous structure amorphous,and the diffraction peaks of ACKZ were sharper,which indicated that the addition of zinc chloride could enhance the structure of product more orderly.ACKZ was a kind of activated carbon material with high microporosity,and its micropore content was between zinc chloride and potassium carbonate activation alone,which proved its synergistic effect.?3?The appearance of ACCM prepared by doping carbon microspheres showed that the surface of ACCM was smooth without bulge structure showing that the carbon microspheres played an important role in enhancing the internal strength of the products.The addition of carbon microspheres mainly fill into the mesoporous structure of products.The results of SEM analysis showed that the carbon microspheres fully filled the product,which promoted the internal structure of the product to form a unified whole and greatly enhanced the strength of the product.Infrared analysis showed that there were a large number of hydroxyl peaks and a small amount of carbon-carbon double bonds in the product ACCM.XRD analysis showed that the product ACCM had no specific diffraction peak,which was a broad peak,indicating that the product ACCM was amorphous structure.BET analysis showed that the specific surface area of product ACCM was 880 m²/g and the average pore size was 1.5 nm,of which the micropore rate was 90%and the mesoporous rate was 1.8%.It indicated that the addition of carbon microspheres affected the structure of product.?4?The results of adsorption test showed that the adsorption effect of self-made activated carbon was much better than that of commercial activated carbon.For different concentration of dye solution,the dye solution with medium concentration of 5 mg/L had the best adsorption efficiency in the early stage.In acid dye solution,the adsorption efficiency of self-made activated carbon could reach 95%.Too high or too low dye temperature was not conducive to the adsorption of activated carbon Stirring physical mode would greatly improve the adsorption efficiency.?5?The electrochemical performance analysis showed that all the products had good double-layer capacitance behavior.After 1000 cycles of charge-discharge test,the specific capacitance remained basically unchanged,indicating that the products could be used as electrode materials.The difference of specific capacitance between ACKZ and ACCM was very small,which indicated that the addition of carbon microspheres had a weak influence on the electrochemical properties of the product.