Synergistic phosphorus removal from water using core–shell manganese–iron nanocomposites: Adsorption performance and recovery potential

Nano zero-valent manganese and nano zero-valent iron were chemically combined to form a bimetallic composite (nZVMI). The synthesized materials were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction, along with kinetics, thermodynamics, and isotherm studies. Their capability, performance, and fundamental mechanisms for adsorbing phosphorus were investigated. Comparative tests demonstrated the synergistic superiority of nZVMI overusing both nZVM and nZVI alone. It was found that the analyzed bimetal acts as a composite with a core-shell structure that can adsorb up to 346.50 mg/g of phosphorus at 0.2 g/L of adsorbent dosage at a pH of 5 and for a 50 mg/L phosphorus solution. The reaction mechanisms of phosphorus using nZVMI were probably described as adsorption, surface complexation, co-precipitation, and electrostatic sorption. The adsorption mechanisms of the synthesized adsorbents fit the second-order pseudo-kinetic model. This study presents a new method for effectively removing phosphorus from water and improves the understanding of phosphorus interactions between nZVM and nZVMI. This bimetallic composite has a sustainable potential for effectively removing phosphorus from real river water with 99.5 % removal efficiency, providing phosphorus recovery, which is one of the priority agendas for global food security.