Activated carbons developed from Algerian agro-waste of palm trunk fiber: characterization and adsorptive capacity for azo dyes removal

In this work, the activated carbon of palm trunk fiber was prepared by the thermochemical activation method for the adsorptive removal of azo dyes known for their toxicity, including methylene blue (MB) and methyl orange (MO) from aqueous solution. This preparation was realized with activated factor phosphoric acid H3PO4 at 450 degrees C in different impregnation ratios, which varied within the following range: 30, 60, 100, and 150 wt.%. Investigated adsorbents were characterized using several methods such as X-ray diffraction, N-2 sorption, Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, and scanning electron microscopy techniques. Also, Boehm titrations and point of zero charge measurements were carried out to give more explication about surface properties. The effect of adsorbent dosage was evaluated and discussed. The results show that the adsorption capacity increases with increasing the mesoporous of the activated carbons. At 150 wt.% H3PO4 ratios were found to be appropriate for efficient adsorption of the (MO) dye (similar to 862 mg center dot g(-1)) and (MB) dye (similar to 508 mg center dot g(-1)). Isotherm data were investigated according to Langmuir and Freundlich equations. The obtained results revealed that the Langmuir model provides the best fit for the cationic MB dye while the Langmuir and Freundlich models offer the best fit for anionic MO dye.