Document Type : Regular Article


1 Gas Engineering Department, Petroleum University of Technology, Ahvaz, Iran

2 Basic ScienceDepartment, Petroleum University of Technology, Ahvaz, Iran,


Ziziphus nuts are abundant in Khuzestan province, Iran, and are considered as an unwanted natural biomass waste. The present study aimed to develop low-cost activated carbon from Ziziphus nuts as a new precursor for phosphate removal from the water environment. Iron oxide modification was performed to simultaneously facilitate adsorbent separation via a simple magnetic process and increase phosphate removal capacity. The iron oxide/activated carbon composite (IOAC) was characterized using XRD, EDX, SEM, and BET methods. The specific surface area for IOAC reached 569.41 m2/g, comparable to that of commercial activated carbon. While other similar biomass-derived activated carbons reached phosphate removal capacity around 15 mg/g, IOAC demonstrated excellent phosphate removal performance as high as 27 mg/g. Also, IOAC showed fast adsorption kinetics, achieving equilibrium in only 60 minutes. On the basis of the results, the pseudo-second-order kinetic model was more consistent with the phosphate adsorption data onto the adsorbent than the pseudo-first-order model. The adsorption results were interpreted using Langmuir, Freundlich, and Webber-Morris diffusion models. The maximum Langmuir adsorption capacity was calculated to be 27 mg/L. The adsorbent was removed from the aqueous solution via a simple magnetic process.


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