Effects of pyrolysis temperature on physicochemical properties of rice husk biochar

This study aims to investigate the effects of pyrolysis temperature ranged from 350 to 650°C on some key physicochemical properties of rice husk biochar. Based on these data, biochar production could be optimized for specific applications in environmental biotechnology, such as carriers for microorganism immobilization or disposal filter in wastewater treatment. By using material analysis techniques (SEM, FTIR, XRD, and BET) as well as conventional methods, rice husk biochars, pyrolyzed in temperature ranged of 350-650°C, have been characterized. Particle density, pH, EC, water holding capacity, and ash content of rice husk biochar tend to increase while biochar yield decreases sharply when increasing pyrolysis temperature. Rice husk biochar produced at 550°C was also determined for specific surface area, elemental composition, surface functional groups, and material structure. The results showed that biochar obtained at 550°C had a particular surface area of around 42.22m2/g. Elemental analysis of rice husk biochar revealed C (10.19%), O (52.74%), and Si (36.16%) were dominant than other elements. Using surface functional group (FTIR) analysis, there existed the O–H group (at frequency 3,443.88cm‒1), –CH3 (2,360cm‒1), and either –C=O or C=C group (in the range of frequency 1,600-1,650cm‒1); the studied rice husk biochar has its point of zero charges at pHPZC 6.8. The XRD diffractogram has presented the overall structure of rice husk biochar was amorphous in nature