Nickel nanoparticles in carbon structures prepared by solid-phase pyrolysis of nickel-phthalocyanine

Nanoscale magnetite (Fe₃O₄) (<15?nm) is known to remove arsenic efficiently but is very difficult to separate or require high magnetic fields to separate out from the waste water after treatment. Anisotropic hexagonal ferrite (BaFe₁₂O₁₉, BHF) is a well-known permanent magnet (i.e., fridge magnets) and attractive due to its low cost in making large quantities. BHF offers a viable alternative to magnetite nanocrystals for arsenic removal since it features surfaces similar to iron oxides but with much enhanced magnetism. Herein, we employ BHF nanocrystalline materials for the first time in arsenic removal from wastewater. Our results show better (75?%) arsenic removal than magnetite of the similar sizes. The BHF nanoparticles, 6.06?±?0.52?nm synthesized by thermolysis method at 320?°C do not show hexagonal phase, however, subsequent annealing at 750?°C produced pure hexagonal BHF in >200?nm assemblies. By using BHF, we demonstrate that nanoparticle removal is more efficient and fixed bed type cartridge applications are more possible.