Efficient multistep arsenate removal ont

This study explores the modification of fly ash (FA) with magnetite (M) to create an effective adsorbent for arsenate removal from water. The approach aimed to enhance adsorption efficiency while utilizing low-cost materials. Characterization of the novel adsorbents was conducted using techniques such as liquid nitrogen porosimetry (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), Mössbauer spectroscopy (MB), and Fourier transform infrared (FTIR) spectroscopy. The optimization of synthesis conditions was performed using the response surface method (RSM). Batch adsorption experiments were executed by varying key parameters including contact time, temperature, pH, and adsorbent mass. The results indicated that the adsorption capacity of the modified adsorbent (FAM) for As(V) reached 19.14 mg g−1, and the process displayed spontaneity with a low endothermic character. Kinetic studies followed a pseudo-second-order model, while the Weber-Morris model suggested that intra-particle diffusion could be the rate-limiting step. The research also highlighted an alternative desorption approach through multiple adsorption/magnetite precipitation processes, resulting in exhausted adsorbent with a capacity of 65.78 mg g−1. This work presents a potential strategy for the valorization of widely available industrial waste.