Removal of Cibacron Blue P-3R (RB 49) dye from aqueous solution using chemo-physically activated biochar from Agave fiber waste

Abstract

This paper presents the use of Agave leaves for the removal of an anionic dye Cibacron Blue P 3R (CB) from aqueous solution. The work reports the preparation of activated material (ALa) by impregnation with H3PO4 and carbon fibers (ALc) by pyrolysis at 800°C, from Agave leaves (AL). The materials were characterized by potentiometric titrations, scanning electron microscope, thermogravimetric analysis, and Fourier transform infrared spectroscopy. Initial pH, contact time, and initial dye concentration were evaluated in batch mode studies. Statistical analysis root-mean-square error (RMSE) was compared in the Langmuir, Freundlich, and kinetic equations. The kinetic investigation was fitted with pseudo-second-order model for both native (AL), calcined (ALc) and activated (ALa) adsorbents with R2 values higher than 0.99. Processes were well described with Langmuir isotherm model at the dye concentration range of 10–250 mg/L for all adsorbents. AL, ALa, and ALc samples exhibited, at pH=2.2, high maximum adsorption capacity of 20.83, 50.76, and 102.04 mg/g respectively. The experimental data are fitted well by the Langmuir in case of native (AL) and activated (ALa) adsorbents, where a high correlation coefficients (R2) and a low root-mean-square errors (RMSE). For the adsorption of CB dye on the calcined material (ALc), the Freundlich mode perfectly describes the adsorption process with a very low-root-mean-squares error (RMSE) = 0.62.