Grapefruit peels as biosorbent: characterization and use in batch and fixed bed column for Cu(II) uptake from wastewater

BACKGROUND A study of copper adsorption onto biosorbents prepared from grapefruit peels (GP) is presented. The objectives of the present analysis were: (1) to evaluate the use of Instant Controlled Pressure Drop (DIC) as a treatment of biosorbents preparation; (2) to assay the modified biosorbents in fixed‐bed columns; and (3) to elucidate an adsorption mechanism of the metal on the modified biosorbents. RESULTS Mercury intrusion porosimetry studies showed that the use of DIC increases the porosity of material 11.3‐fold. Adsorption capacity of GP biosorbents indicate that those prepared using a DIC process had an increase of 32% and by using a subsequent chemical treatment, an enhancement of 69%, compared with simple dried GP peel. In fixed bed adsorption studies, the maximum adsorption capacity of the bed and the minimum adsorbent rate were 52.48 mg g−1 and 24 g L−1, respectively. CONCLUSION Based on the results from the adsorption and characterization studies performed by SEM‐EDS, FTIR and XPS, it is proposed that the adsorption mechanism was a physisorption phenomenon, between oxygen‐containing groups and Cu(II) from water. High adsorption capacity can be achieved using modified GP peels in fixed‐bed columns; therefore, it is feasible to use it as a non‐conventional adsorbent. © 2016 Society of Chemical Industry