TY - JOUR
T1 - Photocatalytic ZnO Foams for Micropollutant Degradation
AU - Guaraldo, Thais Tasso
AU - Wenk, Jannis
AU - Mattia, Davide
N1 - This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
PY - 2021/5/19
Y1 - 2021/5/19
N2 - Photocatalytic foams can concomitantly overcome the disadvantages of slurry and immobilized photocatalysts in water treatment. However, foams have, so far, been restricted to nanoparticles grafting onto inert foam substrates, with the consequent risk of nanoparticle release into the environment. In this work, self-supporting, highly porous photocatalytic zinc oxide (ZnO) foams are produced using a combination of liquid templating and sintering for the first time. Systematic changes in sintering times and temperature affect the foams’ morphology and structure, in turn controlling their photocatalytic activity and stability. Sintering at 900 °C and decreasing sintering times from 20 to 6 h lead to a doubling in surface-area-to-volume ratio and a 30% increase in pore diameter, resulting in a near doubling of the overall quantum yield and degradation kinetics. However, photocorrosion and Zn leaching increase markedly for the shortest sintering time. Optimal sintering conditions at 900 °C for 12 h yield foams capable of effectively degrading the model micropollutant carbamazepine under UV irradiation with high stability, showing no performance decrease over five irradiation cycles corresponding to 20 h of use. This study paves the way to producing self-supporting, highly stable photocatalytic foams for the removal of organic micropollutants in water treatment.
AB - Photocatalytic foams can concomitantly overcome the disadvantages of slurry and immobilized photocatalysts in water treatment. However, foams have, so far, been restricted to nanoparticles grafting onto inert foam substrates, with the consequent risk of nanoparticle release into the environment. In this work, self-supporting, highly porous photocatalytic zinc oxide (ZnO) foams are produced using a combination of liquid templating and sintering for the first time. Systematic changes in sintering times and temperature affect the foams’ morphology and structure, in turn controlling their photocatalytic activity and stability. Sintering at 900 °C and decreasing sintering times from 20 to 6 h lead to a doubling in surface-area-to-volume ratio and a 30% increase in pore diameter, resulting in a near doubling of the overall quantum yield and degradation kinetics. However, photocorrosion and Zn leaching increase markedly for the shortest sintering time. Optimal sintering conditions at 900 °C for 12 h yield foams capable of effectively degrading the model micropollutant carbamazepine under UV irradiation with high stability, showing no performance decrease over five irradiation cycles corresponding to 20 h of use. This study paves the way to producing self-supporting, highly stable photocatalytic foams for the removal of organic micropollutants in water treatment.
KW - ZnO
KW - foams
KW - photocatalysis
KW - photocatalytic foams
UR - http://www.scopus.com/inward/record.url?scp=85102280171&partnerID=8YFLogxK
U2 - 10.1002/adsu.202000208
DO - 10.1002/adsu.202000208
M3 - Article
SN - 2366-7486
VL - 5
JO - Advanced Sustainable Systems
JF - Advanced Sustainable Systems
IS - 5
M1 - 2000208
ER -