Effect of Iron Chloride Addition on Softwood Lignin Nano-Fiber Stabilization and Carbonization

This study presents the effect of iron chloride addition on the production of nanocarbon fibers from softwood Organosolv lignin. It was shown that adding 2% FeCl3 to the lignin solution before electrospinning to produce lignin nanofibers increased the thermal resistance of lignin fibers during stabilization. FTIR and XPS analyses of the lignin fibers stabilized with and without FeCl3 revealed that the temperature rate could be increased in the presence of FeCl3 from 1 to 3 degrees C/min. The optimal temperature to stabilize the lignin fibers was found to be 250 degrees C, as higher temperatures led to thermal degradation. Also, carbon fibers were successfully produced from pure softwood Organosolv lignin fibers. Carbonization tests were conducted under nitrogen and the best parameters were determined to be a ramp of 10 degrees C/min until 600 degrees C with a holding time of 2 h. Furthermore, the effect of 2% FeCl3 addition in the lignin solution was investigated during these processes. XPS analysis showed a 93% carbon content for fibers carbonized with and without FeCl3 addition, while SEM images revealed some surface roughness in fibers with FeCl3 after carbonization. These results confirm that FeCl3 addition influences the carbon nanofiber production.