Process optimization of anionic dye (Melioderm HF Brown G) removal from aqueous solution utilizing adsorbent prepared from Labeo rohita fishbone

Abstract In this study, the prepared bio-adsorbents from Labeo rohita fishbones were used to remove the anionic acid dye Melioderm HF (High Fastness) Brown G (MHFB) from the aqueous solution. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were used to analyze the morphology and chemical composition of fishbone powder (FBP) before and after MHFB dye adsorption. In a batch experiment, factors such as initial dye concentration (100–250 mg/mL), contact time (5–180 min), pH of the solution (2.0–8.0), and the adsorbent dosage (1.0–3.5 g/L) were analyzed for their impact on the dye adsorption process. The batch experiments were studied to evaluate the influence of different operational variables such as pH, adsorbent dosage, contact time, and initial concentration of dye and were found optimum at 2, 2 g/L, 120 min, and 200 ppm, respectively, for maximum dye removal (98.33%) at ambient temperature (298 K). The isotherm models demonstrated that dye molecules were adsorbed heterogeneously in multilayer following the Freundlich isotherm (R2 = 0.9300). The data were fitted for pseudo-second-order kinetics. Thus, L. rohita fishbone could be used as a bio-adsorbent to remove anionic dye from tannery effluents at a minimal cost.