Comparative study of the effective removal of hexavalent chromium via calcium alginate and calcium alginate/Ulva fasciata composite

Abstract The present study revealed for the first time removal of hexavalent chromium Cr(VI) with a high efficiency using an eco-friendly composite beads alginate green alga Ulva fasciata compared to calcium beads. This conclusion was reached in this from comparison by well-known biosorbent material, (CA) studied alginate/ (CA/UF) biocomposite characterization prepared achieved several techniques such as Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive X-ray (EDAX). Brunauer, Emmett, Teller (BET) Barrett, Joyner, Halenda (BJH) analyses were also employed which indicated three-fold increase surface area, mean pore diameter 2.3-fold total volume 14-fold results batch experiments demonstrated fast complete CA/UF maximum (75%) CA. Dubinin–Radushkevich isotherm model reflected physical filling rather than adsorption on walls, giving free (2.24 kJ/mol) greater that CA (0.13 kJ/mol). Furthermore, Brunauer–Emmett–Teller multilayer CA/UF. Flory–Huggins showed more spontaneous CA, negative Gibbs Δ G 0 values − 4.76 6.91 kJ/mol, respectively. Whereas, Temkin higher binding In study, Langmuir least applied among all models, mechanism ions. Intra-particle diffusion beads, application suggested intra-particle is part rate-limiting steps. regeneration decrease 97.4 82.3% three consecutive cycles.