Preparation and characterization of modified corn stalk biochar

To increase the added value of corn stalk and improve the performance of corn stalk biochar, magnesium chloride (MgCl2) was used to modify biochar, and the effects of temperature on the structure and properties of modified biochar were considered. With the increase of temperature, the yield of biochar decreased. There was a marked increase in the number of mesopores and micropores, but the mesopore pore diameter changed to a smaller pore diameter, and the specific surface area remarkably increased. As the temperature increased, the content of C increased, while the range of H and O decreased. In addition, the number of oxygen-containing functional groups and methyl groups decreased, indicating that the structure of biochar became more aromatized. An obvious Mg(OH)2 crystal peak appeared in the X-ray diffraction pattern, which meant that Mg ions were loaded on the surface of biochar. Moreover, the highest removal rate of methylene blue dye by biochar was 83.6%. The authors conclude that temperature and magnesium chloride modification can improve and enhance the performance of corn stalk biochar. These findings will help deepen people’s understanding of biochar modification and serve as a reference for future related research.