Abstract
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.