Enhanced degradation of doxycycline by citric acid-functionalized graphitic
carbon nitride decorated with MIL-88A and FeS: optimization, degradation
mechanism, and degradation pathway
#MMPMID41384055
Eltaweil AS
; Ayoup MS
; Al Nawah JY
; Abd El-Monaem EM
RSC Adv
2025[Dec]; 15
(57
): 48994-49008
PMID41384055
show ga
This investigation provides a new Fenton-like heterogeneous catalyst construct,
citric acid-functionalized graphitic carbon nitride decorated with MIL-88A and
iron sulfide (FeS/MIL-88A@Cit-gCN). The characteristics of
FeS(0.5)/MIL-88A(0.5)@Cit-gCN were scrutinized using different instruments to
identify its surface charge, morphology, elemental and structural compositions,
and crystallinity. The catalytic activity of FeS(0.5)/MIL-88A(0.5)@Cit-gCN was
inspected by a series of adsorption/Fenton-like experiments, evaluating the best
catalytic parameters for efficiently decomposing doxycycline (Dox). The maximum
adsorption% and decomposition% of Dox were 48.78% and 99.40%, respectively, at
H(2)O(2) concentration = 100 mg L(-1), system temperature = 20 °C, pH = 5, and
FeS(0.5)/MIL-88A(0.5)@Cit-gCN dose = 0.01 g. The second-order kinetic model best
represented the Dox decomposition process by FeS(0.5)/MIL-88A(0.5)@Cit-gCN. The
decomposition mechanism of Dox proceeded by a catalytic radical pathway, and most
probably, ?OH was the governing radical in the catalytic medium. The ?OH radicals
were produced through the contribution of the iron, sulfur, and electron-donor
groups of FeS(0.5)/MIL-88A(0.5)@Cit-gCN to activate H(2)O(2). The adsorption
reaction played an excellent role in the decomposition capacity of Dox since the
drug molecules were attached to the FeS(0.5)/MIL-88A(0.5)@Cit-gCN surface by n-pi
interactions, coulombic interactions, and coordination bonds. The recycling study
denoted the durability of FeS(0.5)/MIL-88A(0.5)@Cit-gCN after reusing for five
times. These results render FeS(0.5)/MIL-88A(0.5)@Cit-gCN a premium heterogeneous
catalyst that can be applied at an industrial scale.
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