Sonochemical preparation of polyaniline@TiO2 and polyaniline@SiO2 for the removal of anionic and cationic dyes

Polyaniline (PANI) synthesized by simple CDs (carbon dots) initiated polymerization has formed a composite with TiO2 and SiO2, respectively via a sonochemical method. These PANI@TiO2 and PANI@SiO2 composites were proven as effective adsorbent materials to rapidly adsorb the anionic and cationic dyes from wastewater at neutral pH and ambient temperature. Selected popular cationic and anionic organic dyes consisted of methylene blue (MB), brilliant blue (BB), Evans blue (EB), crystal violet (CV), Congo red (CR), rhodamine B (RB), and rhodamine 6G (R6G). The adsorption equilibria were governed by Langmuir and Freundlich isotherms. The kinetic results revealed that the PANI@TiO2 and PANI@SiO2 composite materials synthesized via the sonochemical method are efficient adsorbents compared to other adsorbent materials for the removal of organic dyes from the water. The adsorbed dyes were effectively desorbed from the composites, rendering the reusability of PANI@TiO2 and PANI@SiO2. The estimated adsorption capacities of PANI@TiO2 and PANI@SiO2 composites were 89, 93, 80, 94 and 74, 71, 61, 61 mg/g for MB, CR, CV, and R6G, respectively.