Adsorption behaviors of cationic and anionic dyes from aqueous solution on nanocomposite polypyrrole/SBA-15

The present research focuses on the synthesis and the modification of mesoporous silica SBA-15 using in situ polymerization of pyrrole. The structural/textural and morphological features of adsorbents were investigated through X-ray diffraction, nitrogen sorption at 77 K, thermogravimetric analysis, Fourier transform infrared spectroscopy, zeta potential measurements and scanning electronic microscopy. Several nanocomposites containing different percentages of polypyrrole were tested for the adsorption of both anionic and cationic dyes. The effect of adsorbent nature, pH, contact time, adsorbent dose and initial dye concentration were investigated and discussed in terms of adsorption efficiency. The adsorption efficiency of MO dye increased in the following sequence: SBA-15 < PPy/SBA-15(1%) < PPy/SBA-15(10%) < PPy/SBA-15(30%) < PPy/SBA-15(50%). The adsorption of MB dye is preferably carried out by parent material SBA-15 and nanocomposite PPy/SBA-15(1%). The experimental data were verified by the Langmuir and Freundlich isotherms, and the kinetic data were fitted by pseudo-first-order and pseudo-second-order models. The obtained results showed that the adsorption of the both dye by nanocomposite PPy/SBA-15 followed Langmuir adsorption isotherm models and pseudo-second-order kinetics. The adsorbed amounts recorded for MO and MB dyes are 41.66 and 58.82 mg/g, respectively.