Multiwalled carbon nanotubes/zeolite composite for dye degradation under sunlight

MWCNT/Zeolite composite was successfully obtained by growing multiwalled carbon nanotubes over natural zeolite chabazite using chemical vapor deposition (CVD). The structural and morphological properties were studied using Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The growth of the MWCNTs on the natural zeolite exchanged with Fe and Ni was observed, which functioned as a catalyst. A higher number of structural defects was found in the nanotubes grown on the zeolite than in the commercial and pure nanotubes grown by CVD. The photocatalytic/adsorption performance of the composite was determined by following the methylene blue (MB) degradation under sunlight irradiation and dark conditions. UV–VIS spectra analysis showed that MWCNT/Zeo composite removes MB dye faster than pure MWCNT and commercial multiwall carbon nanotubes (MWCNT-Sigma). The results indicate that the MWCNT/Zeo composite's removal activity increased in the presence of natural sunlight irradiation, showing a dye discoloration of up to 98% in 210 min, with an estimated apparent rate constant of the first-order kinetics (k_app) = 1.67 × 10⁻² min⁻¹.