Spent Tea Biochar Production: Characterization and Environmental Applications

The world is suffering from a myriad of environmental issues, including but not restricted to solid wastes management, water scarcity and water and soil pollution and governance. In Lebanon, most rural municipalities dump waste into valleys or leave ituntreated until people burn it themselves. Simultaneously, water resources in Lebanon are suffering from pollution induced by urban as well as industrial wastewater, which includes pharmaceutical compounds. The polluted water has resulted in disease outbreaks and has also affected the daily lives and the overall health of people.

In this study, we intend to turn a common form of waste into value through its conversion into biochar for subsequent use as an efficient material for industrial wastewater treatment. To this end, spent tea leaves were dried, ground and pyrolyzed at 350, 450, 550 and 650 ͦC in a muffle furnace in a total absence of oxygen. The biochar production yields ranged from 48% at 350 °C to only 30% at 650 °C. The pH and electrical conductivity values of the synthesized biochars increased with the increase in the pyrolysis temperature. The highest obtained pH was 10.45 and the highest electrical conductivity was 13.6 mS/cm, both assessed at 650 °C. Preliminary batch adsorption tests showed that biochars efficiently removed methylene blue, amoxicillin and diclofenac at percentages of 100%, 80% and 51%, respectively.