Valorization of agricultural residues through its transformation into sustainable filters for water treatment

Finding a sustainable solution to the increasing amount of organic waste generated, and reducing air, soil and water pollution are two most pressing environmental issues today. In both problems, agriculture plays a crucial role. Within this context, this study aims to valorize abundant agricultural waste via its transformation into activated carbon (AC), useful for the removal of emerging organic contaminants (EOCs) in water.
Thus, rice husk (RH) and almond shell (AS) were characterized, pyrolyzed and tested as feedstock for ACs to be used as water filters. In addition, chemical (with KOH) and physical activation (with water vapor) of the pyrolyzed materials were performed.
The elemental composition and physical properties were suitable in both cases (alkaline pH, high water retention capacity, Carbon content and Iodine index). The specific surface area (SSA-BET) increased significantly to values 600 m2 gr-1 on the ACs produced from physically activated and pyrolyzed RH.
Furthermore, adsorption tests of anti-inflammatory and antibiotic compounds in water showed that ACs produced from RH were able to adsorb up to 100 % of the these persistent EOPs, performing similarly to commercial AC.

 

Acknowledgements:
This study received financial support in the framework of the Project RICERES4CHANGE (grant TED2021-130964B-I00), by the Spanish Agency of Research (MCIN/AEI/10.13039/501100011033) and the European Union (Next Generation EU/PRTR funding).
A.M. Sánchez-Martín thanks The Spanish Ministry of Science and Innovation (MICIN) for her contract as Technical Support Personnel (PTA2021-020000-I). M. Arenas is thanked for this technical and analytical support.