Removal of Co2+, Cu2+ and Au3+ ions from contaminated wastewater by using new fluorescent and antibacterial polymer as sorbent

New Schiff base polymer was synthesized through polycondensation reaction of dialdehyde (2,2 '-hexamethylenebis(oxybenzaldehyde)) and diamine (dapsone). The resulting polymer was characterized through CHN analysis, (HNMR)-H-1, FT-IR, UV-Vis spectroscopy, fluorescence spectroscopy, TG/DTA and SEM. The synthesized polymer was fluorescent and showed violet color emission. The antimicrobial activity of the polymer was tested, and the polymer showed moderate antibacterial activity against Shigella flexneri. New effective method was developed for the removal of Co2+, Cu2+ and Au3+ ions from contaminated wastewater, and the synthesized polymer was employed as sorbent. Multivariate optimization of parameters (pH, concentration, amount and time) was attained through factorial design (face-centered Draper-Lin composite design) with 18 batch experiments. The method was applied successfully at predicted optimum conditions for the removal of heavy metal ions (Co2+, Cu2+ and Au3+) from contaminated wastewater samples. The synthesized sorbent polymer removed up to 78% Co2+, 99% Cu2+ and 98% Au3+ from wastewater samples. The concentration of metal ions before and after adsorption was measured through AAS. The presence of metal ions on the polymer surface was confirmed through SEM and EDX analysis of the polymer after adsorption. Equilibrium of the adsorption process was studied through Langmuir, Freundlich and D-R isotherms, and kinetics was studied through Lagergren pseudo-first-order, Lagergren pseudo-second-order and intra-particle diffusion models.