Remediation of organic
pollutant matrixes
from wastewater by photodegradation using different heterojunctions
is extensively studied to improve performance for potential application.
Brilliant black (BB) and
p
-nitrophenol (PNP) have
been detected in the environment and implicated as directly or indirectly
carcinogenic to human health. This work analyzes their elimination
from aqueous solutions under visible-light irradiation with composites
of cobalt(II, III) oxide and bismuth oxyiodides (Co
3
O
4
/Bi
4
O
5
I
2
/Bi
5
O
7
I). The synthesized nanomaterial properties were investigated
using various techniques such as BET, SEM/EDS, TEM, XRD, FTIR, PL,
and UV–vis. All the nanocomposites absorbed in the visible
range of the solar spectrum with band gaps between 1.68 and 2.79 eV,
and the specific surface area of the CB2 composite increased by 35.8%
from that of Bi
4
O
5
I
2
/Bi
5
O
7
I. There was an observed massive reduction in the rate
of electron and hole recombination, and the band gaps of the composites
decreased. The mineralization of PNP and BB was followed by determination
of the total organic carbon
with reductions of 93.6 and 83.7%, respectively. The main active species
were the hydroxyl radicals, while the superoxide anion radical and
generated holes were minor as confirmed by radical trapping experiments.
The optimum pHs for degradation of PNP and BB were 9.6 and 5.3, respectively.
The enhanced performance of the catalyst was due to C-scheme heterojunction
formation that reduced the electron and hole recombination rate and
was attributed to strong adsorption of the pollutants on the photocatalyst
active surface. The nanocomposite is apposite for solar energy-driven
remediation of organic pollutants from environmental aqueous samples.