Nano-sized hematite-assembled carbon spheres for effectively adsorbing paracetamol in water: Important role of iron

This study developed a new alpha-Fe2O3 (hematite) nanoparticles-loaded spherical biochar (H-SB) through the direct pyrolysis of glucose-derived spherical hydrochar and FeCl3. The optimal impregnation ratio (hydrochar and FeCl3) was 1/1.25 (wt/wt). H-SB was applied to remove paracetamol (PRC) from water. Results indicated that H-SB exhibited a relatively low surface area (127 m(2)/g) and total pore volume (0.089 cm(3)/g). The presence of iron particles in its surface was confirmed by scanning electron microscopy with energy dispersive spectroscopy. The dominant form of iron nanoparticles (alpha-Fe2O3) in its surface was confirmed by X-ray powder diffraction and Raman spectrum. The crystallite size of alpha-Fe2O3 in H-SB was 27.4 nm. The saturation magnetization of H-SB was 6.729 cmu/g. The analysis of Fourier-transform infrared spectroscopy demonstrated that the C-O and O-H groups were mainly responsible for loading alpha-Fe2O3 nanoparticles in its surface. The adsorption study indicated the amount of PRC adsorbed by H-SB slightly decreased within solution pH from 2 to 11. The adsorption reached a fast saturation after 120 min. The Langmuir maximum adsorption capacity of H-SB was 49.9 mg/g at 25 degrees C and pH 7.0. Ion-dipole interaction and pi-pi interaction played an important role in adsorption mechanisms, while hydrogen bonding and pore filling were minor. Therefore, H-SB can serve as a promising material for treating PRC-contaminated water streams.

Automated summary

In this study, a new type of alpha-Fe2O3 nanoparticles-loaded spherical biochar (H-SB) was developed for the removal of paracetamol (PRC) from water. The H-SB exhibited a relatively low surface area and total pore volume, with the presence of iron particles on its surface. The dominant form of iron nanoparticles in H-SB was confirmed to be alpha-Fe2O3, with a larger crystallite size and saturation magnetization. The adsorption study showed a slight decrease in the amount of PRC adsorbed by H-SB within the pH range of 2 to 11, reaching saturation after 120 minutes.