Simple One-Step Synthesis of Nipa Frond-Derived Magnetic Porous Carbon for Decolorization of Acid Yellow 23
Linh Thi Kim Nguyen, Nguyễn Quang Long, Hung Minh Nguyen, Thuan Minh Nguyen, Hung Hoa Lam, Tuyet‐Mai Tran‐Thuy, Dung Van Nguyen
Abstract
Nipa is an abundant, underutilized palm whose major part is its fronds. Nipa fronds (NF) were, therefore, valorized as a renewable carbon resource for the preparation of advanced magnetic porous carbon (MPC) via simple one-step pyrolysis with FeCl3 addition as a magnetic precursor. Properties of the obtained material were determined by X-ray diffraction (XRD), nitrogen adsorption and desorption isotherms, vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) images, energy-dispersive X-ray (EDX) spectroscopy, and Fourier-transform infrared (FTIR) spectroscopy. XRD results showed that Fe3O4 along with Fe0 particles were formed in the porous carbon base. FeCl3-activation of NF yielded MPC with a high specific surface area (SBET) of 330 m2/g, a large total pore volume (Vtotal) of 0.26 cm3/g, and a strong specific saturation magnetization of 7.65 emu/g. Subsequently, MPC was explored for the removal of acid yellow 23 (AY23) using H2O2 as an oxidation agent. Before H2O2 addition, MPC (0.80 g/L) at pH 3.0 partly eliminated AY23 (initial 100 ppm) with an adsorption capacity of 14.5 mg/g. In further catalytic oxidation with 200 ppm of H2O2, MPC removed 89.1% of AY23 within 120 min. Moreover, AY23 decolorization with different MPC samples obeyed pseudo-first-order kinetics, with the greatest rate constant being 0.0186 min−1. Interestingly, the utilized MPC samples could be easily removed from the treated media using a magnet. Altogether, the findings suggest that low-cost magnetic porous carbon produced from one-step pyrolysis of FeCl3-loaded nipa frond might be applied to the treatment of acid yellow 23 in wastewater due to its relative adsorption capacity, efficient catalytic performance, and powerful magnetic separability.