Investigating the catalytic degradation of dissolved organic matter in actual coking wastewater by AC/Fe–Co nanoparticles using spectroscopic techniques

An activated carbon loaded Fe–Co nanometer material (AC/Fe–Co) was synthesized for catalytic degradation of coking wastewater. Synchronous fluorescence (SFS), Fourier transform infrared spectroscopy (FTIR) combined with two-dimensional correlation spectroscopy (2D-COS) were used to reveal the degradation of fluorescent components in coking wastewater dissolved organic matter (DOM). The results showed that nano-AC/Fe–Co catalyst can degrade coking wastewater in a broad range of pH (3–11). Total organic carbon (TOC) removal rate can reach 85.46%, and more than 86.00% of fluorescent components in DOM can be removed by nano-AC/Fe–Co catalyst. The result of 2D-SFS-COS indicated that the change sequence of these components was in the following order: 490, 400, 335, 325, 365, 380, 430, 273, 285, and 265 nm, indicating that humic-like at long wavelength (e.g. 490 nm and 400 nm) can be degraded preferentially, followed by fulvic-like (e.g. 335 nm, 325 nm, 365 nm, and 380 nm), humic-like (430 nm) and protein-like substances. Meanwhile, the preferential sequence of functional groups was in the following order: 1700–1900, 1548, 1080, 1214, 1010, 1652, 1140, and 1365 cm −1 . The result of moving window 2D-COS (MW2D-COS) showed that protein-, fulvic- and humic-like substances can also be removed within 0 to 30 min, which have occurred the transition at about 20 min. TOC removal rate by nano-AC/Fe–Co catalyst can reach more than 60.00% after three times reuse, suggested an excellent repeatability and stability. Herein, spectroscopic techniques in combination with 2D-COS can be used as feasible approaches to reveal the catalytic degradation characteristics of DOM in actual coking wastewater.