Valorization of manila tamarind seed coat waste biomass for dye removal

Abstract

Valorization of Manila Tamarind (Pithecellobium dulce) seed coat as adsorbent, for Nanoparticle (NP) and Biochar synthesis was studied. Seed coat was employed in extract preparation for the green synthesis of Copper Oxide and Zinc Doped Copper Oxide nanoparticles . The retentate seed coat powder (fine and coarse) and direct seed coat powder (fine and coarse) were then further utilized to prepare Biochar (BC). Two distinct dye pollutants were selected to evaluate the efficacy of prepared adsorbents. Removal of Methylene Blue (MB) dye from aqueous solution was studied using the nanoparticle alginate beads and the adsorption parameters were analyzed, whereas the removal of Malachite Green (MG) dye from aqueous solution was studied using the Biochar followed by determination of adsorption parameters. Results showed that zinc-doped copper oxide nanoparticle alginate beads with 0.2 M doping concentration had the highest removal of 94 % with 2 g/L dosage, 50 mg/L initial dye concentration at pH 6 with 8 h of contact time, at 25°C temperature. The adsorption process followed the Langmuir isotherm model and the Intraparticle diffusion kinetic model. Biochar synthesized from fine seed coat powder used in the extract preparation showed the highest removal of 99.58 % at 50 mg/L initial MG concentration at 25°C, 150 rpm, 1.5 g/L dosage, and 4 hr of contact time. In a nutshell, it provides an efficacious way for utilizing biomass as biochar & nanoparticles to manage solid waste and simultaneously treat toxic dye based liquid effluents.