Abstract
In this study, we assessed the efficacy of coupling coagulation-flocculation-sedimentation (CFS) with adsorption onto a biosorbent (corncob) for the removal of textile dyes from aqueous solutions. Two synthetic dyes, Bemacron Blue RS 01 (BB-RS01) and Bemacid Marine N-5R (BM-N5R), were selected for examination. Initially, aluminum sulphate (Al2(SO4)3.18H2O) served as the coagulant, followed by the addition of superfloc 8396 as a flocculation polymer. Corncob (CC) acted as the biosorbent material for adsorption. We optimized coagulation parameters, including coagulant and flocculant doses, and assessed pH influence. In the adsorption phase, we investigated adsorbent mass, particle size, pH, temperature, contact time, and initial dye concentration. Analytical techniques such as FTIR, SEM, TGA, BET, and pHpzc were employed to characterize corncob (CC). Both Langmuir and Freundlich isotherm models were employed to analyze equilibrium adsorption data, with the Langmuir isotherm yielding the highest correlation (0.94 < R2 < 0.97). Our results demonstrated significant reduction in dye concentration through CFS, achieving elimination rates of 94% at pH 6 for BB-RS01 and 90.3% at pH 4 for BM-N5R. Corncob's adsorption for each dye was notably influenced by solution pH during the adsorption process, with removal rates of 26.19% observed at pH 6 for BB-RS01 and 7.69% for BM-N5R at pH 4. Maximum dye adsorption capacities were 99.01 mg/g for BB-RS01 and 46.08 mg/g for BM-N5R. This study underscores the effectiveness of coupling CFS with corncob adsorption for efficient and economical dye removal, especially with agricultural waste as an adsorbent material.