ZnO and black TiO2 have been selected as the
most efficient
materials for organic pollution abatement due to their increased efficiency
when compared to other materials. However, the concept of green chemistry
makes it desirable to design green synthesis approaches for their
production. In this study, black TiO2 was synthesized using
an environmentally safe synthetic technique with glycerol as a reductant.
ZnO was prepared by using ionic-liquid-based microwave-assisted extracts
of Polygonum minus. To investigate
the materials′ potential to photodegrade organic pollutants,
methylene blue (MB) and phenol were chosen as model organic pollutants.
Both materials were found to exhibit spherical morphologies and a
mesoporous structure and were efficient absorbers of visible light.
ZnO exhibited electron–hole pair recombination lower than that
of black TiO2. Black TiO2 was discovered to
be an anatase phase, whereas ZnO was found to have a hexagonal wurtzite
structure. In contrast to black TiO2, which had a surface
area of 239.99 m2/g and a particle size of 28 nm, ZnO had
a surface area of 353.11 m2/g and a particle size of 32
nm. With a degradation time of 60 min, ZnO was able to eliminate 97.50%
of the 40 mg/L MB. Black TiO2, on the other hand, could
reduce 90.0% of the same amount of MB in 60 min. When tested for phenol
degradation, ZnO and black TiO2 activities were reduced
by nearly 15 and 25%, respectively. A detailed examination of both
ZnO and black TiO2 materials revealed that ZnO has more
potential and versatility for the degradation of organic pollutants
under visible light irradiation.