Adsorption on porous carbon material is known to be effective to remove antibiotics. In the presented study, CNT as well as PAC act as adsorbent material, but PAC exhibits a much larger specific surface and therefore increases the adsorption capacity. CNT serves as “backbone” of a freestanding, stable structure, which enables the water to be easily removed from the adsorbent afterwards. This way, the production of a toxic carbon sludge is prevented and the adsorbent can easily be regenerated.
Prof. Matthias Wessling and his co-workers at RWTH Aachen University, University of Ghent and the DWI – Leipniz Institute for Interactive Materials, Aachen, fabricated microtubes from dispersions of PAC, CNT, and a dispersing agent in water by forcing the dispersion through the lumen of hollow fiber membranes in dead-end filtration mode, drying the cake and pulling it out of the membrane. The microtubes had an outer diameter of less than 2 mm and a wall thickness of about 200 nm.
The PAC/CNT were fabricated with different loads of PAC and tested with respect to their adsorption capacity. Aqueous solutions of the antibiotic sulfamethoxazole were treated by using the new adsorbents. To regenerate the loaded microtubes, hydrogen peroxide and ferrous iron were added to start an advanced oxidation process (Fenton process) that leads to the oxidization of the adsorbed pharmaceutical. Besides the unique structure of the adsorbing material, the study first reported the impact the effect of elevated temperature during regeneration via homogenous Fenton process.
The original publication can be found under https://doi.org/10.1016/j.jhazmat.2020.122133.