Remazol Brilliant Blue R (RBBR) dye and phosphate adsorption by calcium alginate beads modified with polyethyleneimine.

This study concerns the preparation of novel adsorbent prepared from calcium alginate bead modified with polyethyleneimine (PEI-CaAlg). The adsorption capacity of the PEI-CaAlg was examined by Remazol Brilliant Blue R (RBBR) and phosphate adsorption. PEI-CaAlg showed high removal efficiencies for RBBR (90.48%) and phosphate (88.10%). The removal of both RBBR and phosphate onto the PEI-CaAlg followed the Freundlich isotherm and the second-order model. The adsorption was studied in terms of thermodynamic and found to be feasible and spontaneous in nature. The reusability of the modified alginate beads was also examined up to five cycles. The removal efficiency was 90.48% at the first cycle and decreased to 75.15% at the end of the fourth cycle. The adsorption of color and phosphate from real textile wastewater was also instigated. The removal efficiencies for color and phosphate ions reached 80.24% and 90.00%, respectively. Therefore, the prepared PEI-CaAlg can be considered as a novel, eco-friendly, and cost-effective adsorbent for simultaneous dye and phosphate adsorption. PRACTITIONER POINTS: This study aims to modify the surface of calcium alginate beads with polyethyleneimine (PEI). The adsorption of RBBR and phosphate by the modified alginate beads (PEI-CaAlg) was investigated. PEI is an organic polymer with a linear/branch shape, which can increase the active sites on the adsorbent surface. PEI has one nitrogen atom in every three atoms provides a positive charge that can complex with the negatively charged molecules. The adsorption of RBBR and phosphate were carried out onto PEI-CaAlg.