A Hydrochar was prepared from activated sludge of wastewater treatment plant using hydrothermal carbonization at 250 °C for 4 hours. The SEM image result was found as the attached one.
The morphology of the hydrochar gives like roll and I did not get paper which helps me to explain.
Please, can you help me to explain the SEM result and do you have a paper which have like this results?what do the rolls indicate?