Hollow magnetic Fe₃O₄@NH₂-MIL-101(Fe) derived from metal-organic frameworks are fabricated through a general facile strategy. The synthetic parameters are regulated to control the shape of the as-prepared samples. The concentration of phosphates decreased sharply from the initial 0.60 to 0.045 mg.L⁻¹ with the exposure time in 50 minutes. The correlation between the most significant parameters such as contact time, adsorbent dose, pH, as well as adsorption capacities was optimized and the effects of these parameters on the removal efficiency of phosphates were investigated. Surface functionalization of magnetic hollow materials is a well-designed way to bridge the gap between high adsorption activity, excellent separation and recovery of phosphates from the water treatment system. Therefore, it exhibits a remarkable selective removal of phosphates from aqueous solution.

A facile generic environmental strategy is employed to prepare hierarchical yolk–shell hybrid NiO@C materials viz. metal–organic frameworks. The intrinsic yolk–shell nature as well as the multi-element characteristics of active components of the unique nanostructures contributes greatly to the outstanding electrochemical performance.