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

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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. Schematic representation of the preparation of adsorbents and its application as an adsorbent in individual and simultaneous dye removal.