Optimization of physical activation process for activated carbon preparation from water caltrop husk

Abstract

In the work, water caltrop husk (WCH), locally agricultural residue generated in large quantities, was evaluated as a potential precursor for preparing mesoporous activated carbon (AC) by physical activation under the matrix of activation temperature (600-900℃) and holding times (i.e., 0-150 min). The pore and chemical properties of the resulting AC products, including porosity, true density, elemental analysis (EA), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and Fourier-transform infrared spectroscopy (FTIR), were determined to find the optimal activation conditions. From the data on the analysis of AC properties, the activation temperature at around 800℃ for holding time of 45 min was observed to produce the optimal WCH-AC product with the Brunauer-Emmett-Teller (BET) surface area of 972.56 m 2 /g, total pore volume of 0.55 cm 3 /g, and porosity of 0.476. Its corresponding mesopore volume and mesopore percentage reached up to 0.19 cm 3 /g and 35%, respectively. In addition, the opposite effect was also observed for the resulting AC products activated at 800℃ under different holding times, indicating the pore enlargement and/or collapse at holding time increased from 45 to 60 min. Based on the chemical analyses, the high oxygen content was found on the surface of the resulting AC product, which could be indicative of slight polar nature (i.e., hydrophilicity) due to the oxygen-containing functional groups.

Optimization of Physical Activation Process by CO2 for Activated Carbon Preparation from Honduras Mahogany Pod Husk

“…The pyrolysis-activation experiments were described in previous studies [14][15][16][17][18]. In this work, about 5 g of dried SMK was fed into the physical activation system, which was performed at a heating rate of about 10 • C/min.…”