Utilizing low-cost mausambi peel-derived adsorbents for the effective treatment of complex industrial dye mixture in wastewater: Unravelling the adsorption mechanism

Abstract

The complex nature of wastewater due to the presence of multiple contaminants has made water treatment a tedious process. The development of effective adsorbents which are capable of removing multiple contaminants from wastewater is the call of the hour. The present study investigates the potential of mausambi-peel (MP) derived adsorbents for the removal of a dyes from a complex mixture of both cationic and anionic dyes (methylene blue (MB), methyl orange (MO), rhodamine B (RhB), and crystal violet (CV)), which are lacking in the existing available reports. A series of samples were prepared by pyrolysis of MP at 300, 500, and 700 °C. The pyrolyzed samples prepared at 300 °C (MP3) was found to exhibit maximum efficiency in individual adsorption studies showing removal of 97.68 %, 29.11 %, and 75.27 % for MB, RhB, and CV, respectively. No adsorption of MO was observed. MP3 was further explored for simultaneous removal of dyes from a synthetic dye mixture and exhibited a removal of 50.80 %. Kinetic, pH, and isothermal studies were also performed for more in-depth knowledge regarding the nature of adsorption. Thus, the highlight/novelty of this study includes, use of low-cost adsorbent as a one-point solution to the existing pollution challenge to simultaneously treat cationic and anionic dyes and a detailed adsorption mechanism for each dye in acidic in basic medium. The present study contributes to the real-time treatment of the wastewater and is one of few reports available on treatment of complex dye mixture with more than two dyes.