Production and application of activated carbon obtained from the thermochemical degradation of corn cob

Abstract

The present work aims to perform the thermal degradation of corn cob for the production of activated carbon, which is used in a column adsorption system for the dechlorination of supply water. The biomass under study and the product generated by pyrolysis in a fixed bed reactor were analyzed using classical methods (moisture, volatile materials, ash and fixed carbon, lignin, cellulose, hemicellulose and apparent density) and instrumental methods (thermogravimetry and CNH). In the pyrolysis process, the following parameters were studied: temperature (360 to 640 ^oC) and heating rate (13 to 27 ^oC/min). The reaction time was 30 minutes. The dechlorination test using the activated carbon obtained in this research was carried out in an adsorption column in continuous flow at an average flow rate of 6 mL/min. The iodine number of the adsorbent produced in this research was calculated. The results obtained showed that the carbon content (44%) and the lignin content (28%) point to the use of residual biomass studied in this research for the production of activated carbon via the thermal route. The highest activated carbon yield was 71.12% at a temperature of 360 °C with a heating rate of 20 °C/min. While the minimum yield was 21.6% with a temperature of 600 °C and a heating rate of 25 °C/min. The iodine number of the activated carbon produced at 640 ^oC was 820 mgI₂/g. In the adsorption test, the following coefficients from the Thomas model were obtained: kTH = 0.0093 mL/mg.min and qo = 98 mg/g, when a liquid flow equal to 9.9 mL/min was used. The adsorption capacity of coal is related to the flow rate of the dye solution, being noticed that the higher the liquid flow rate in the column, the higher the adsorbate mass transfer coefficient.