Metal pollutants produced by industrial wastewaters have become a global concern given their impact on the environment and human health. The purpose of this study was to assess the polyphenols content and the iron chelating activity in the peels of two pomegranate varieties. After the biomass characterization via FT-IR, point of zero charge and surface functional groups analysis, the lead adsorption was then investigated by batch method. Finally, the regeneration of the biomasses was performed by acidic desorption. Polyphenols content of the red peels extract was higher than the yellow one; 102.9±0.9 and 85.9±1.3 mg GAE/g of dry weight, respectively with a half iron chelation inhibitory concentration (IC 50 ) of 227.2±1.7 and 235.9±3.2 µg.mL -1 of extract, successively. For the adsorption isotherms of lead onto the red and yellow pomegranate peels, the Langmuir model was more fitting with an adsorption capacity (Q max ) of 90 and 89.25 mg.g -1 , respectively. The kinetic data corresponded better to the pseudo-second order model. The acidic desorption of lead was successful with a high percentage of recovery. The results demonstrate the effectiveness of these biomasses as biosorbents for lead removal from aqueous solutions with the possibility of their reuse.

The hexavalent chromium (Cr(VI)) released in industrial wastewaters can cause adverse effects on both the environment and human health. This study aimed to investigate the efficiency of the red and yellow pomegranate husk powders (RHP and YHP) as natural quenchers for free radicals and as adsorbents towards Cr(VI) ions. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) surface area analyses were used for biosorbent characterization. The antiradical activity was assessed via 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. The adsorption isotherms and kinetics were conducted by the batch method. The results showed the roughness and heterogeneity of the biosorbent surface in the presence of active functional groups. At a dose of 5 mg, both biomasses showed a radical inhibition activity (I) > 85% for DPPH, and (I) > 91% for ABTS. Finally, the isotherms modeling showed that the Langmuir model was the best fit with a maximum adsorption capacity (Qmax) of 413.22 and 403.22 mg/g at pH 2 within 60 min with a solid/liquid ratio (S/L) of 0.5 mg/mL for RHP and YHP, respectively. The kinetic data aligned better with the pseudo-second-order model. This study demonstrates the effectiveness of these biomasses as natural quenchers for free radicals and as biosorbents for Cr(VI) removal from contaminated waters.