Sustainable removal of metanil yellow from aqueous systems via adsorption on Jatropha biodiesel cake nanobiomaterial

Abstract

The biosorption behaviour of metanil yellow from aqueous solution has been investigated in a batch system using a lowcost biochar-based nanobiomaterial prepared from Jatropha oil cake (JOC). The optimum pH was 4.0, which provided a maximum biosorption capacity of 21.71 mg/g and the equilibrium was established in 90 min. Kinetic analysis indicated that the contribution of intraparticle diffusion increased with dye concentration, whereas the apparent influence of film and pore diffusion decreased. Equilibrium data was well represented by the Sips isotherm followed by the Langmuir model, which confirmed monolayer coverage with maximum sorption capacity of 24.3 mg/g. Transmission Electron Microscopy (TEM) revealed primary particles in the nanoscale range (≈60–80 nm), which exhibited partial aggregation. Fourier Transform Infrared Spectrometer (FTIR) analysis suggested the involvement of ion-exchange and surface complexation during the biosorption process. Desorption studies showed that up to 96.3% of metanil yellow could be recovered from the biochar using acetone. The results demonstrated that the nanobiomaterial derived from Jatropha biodiesel cake could be leveraged as a low-cost adsorbent for the removal of dye from the water environment.