Environmental engineering approach using Fe-Co-S nanomaterials for removal of Rhodamine B in wastewater: preparation, performance, and mechanism

Fe-Co-S (FeCoS) nanomaterials with good recycling abilities were prepared by a hydrothermal method, and their adsorption properties twords Rhodamine B (RhB) were investigated. Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometer (EDS), X-ray Diffraction (XRD), N2 adsorption-desorption isotherms, Brunel Emmett Taylor (BET) surface area, and Fourier Transform Infrared Spectroscopy (FTIR) were used to characterize the materials and analyze their physicochemical properties. The effects of temperature, pH, and adsorbent dosage on the adsorption performance of FeCoS were also investigated. The results showed that the equilibrium time for the adsorption of rhodamine B by FeCoS was 150min. The adsorption process followed the Langmuir isotherm with a pseudo-second-order kinetic model. It suggests that the adsorption is mainly controlled by chemisorption and belongs to homogeneous monolayer adsorption. The thermodynamic fitting of the adsorption process showed that the adsorption of RhB by FeCoS is spontaneous and accompanied by an endothermic reaction, and the maximum adsorption capacity reached 578.03mg/g at 318K with a removal rate of 98.3%. The removal rate of FeCoS was maintained at 89.95% after five cycles, which was of great potential for practical application in the treatment of dyestuff wastewater.