Towards a win-win chemistry: extraction of C.I. orange from Kamala fruit (Mallotus philippensis), and simultaneous exercise of its peels for the removal of Methylene Blue from water

Abstract

Kamala fruit (Mallotus philippensis), hereinafter MP, has been simultaneously exercised for the extraction of a natural dye, C.I. orange and its peels were converted into an efficient adsorbent for the rapid removal of methylene blue (MB) dye from aqueous solutions. The material has been characterized by Fourier Transform Infra-red (FTIR),Field Emission Scanning Electron Microscopy- Electron dispersive spectroscopy (FESEM-EDS), Brunauer–Emmett–Teller (BET) surface area, and pHZPC. FTIR suggests the presence of polyphenolic moieties responsible for adsorption, whereas FESEM confirms the porous texture. Optimization of process variables such as contact time, pH, adsorbent dose, and temperature of operation indicates that the adsorption gets modulated by the pH, with a best at 11. The Freundlich model (R2 = 0.994), and pseudo-second-order kinetics (R2 = 0.999) best describe the adsorption pathway. Dilute hydrochloric acid is sufficient to induce >66% regeneration, which ensures reusability. With the maximal uptake for MB is 30.2 mg/g at ambient conditions, the superiority over the existing materials has been confirmed. Treatment of dye containing industrial effluent suggests about a 50% reduction in one cycle. It can be concluded that both-way benefits, namely natural dye extraction and preparation of a peel-based adsorbent for methylene blue removal from aqueous solution, can be achieved using the kamala fruit peels.