Functionalization of biochar using FeO nanoparticles and MXene for rapid removal of methyl blue and lead from both single and binary systems.

The synthesis of polymeric magnetic composites is a promising strategy for the rapid and efficient treatment of wastewater. Lead and methyl blue are extremely hazardous to living organisms. The sorption of Pb and the dye methyl blue (MB) by biochar is an ecologically sustainable method to remediate this type of water pollution. We functionalized biochar with FeO and MXene, resulting in FeO/BC/MXene composites with an efficient, rapid, and selective adsorption performance. Based on X-ray photoelectron and Fourier transform infrared spectrometry, we found that the FeO/BC/MXene composites had an increased number of surface functional groups (F, C[double bond, length as m-dash]O, CN, NH, and OH) compared with the original biochar. The batch sorption findings showed that the maximum sorption capacities for Pb and MB at 293 K were 882.76 and 758.03 mg g, respectively. The sorption phenomena obeyed a pseudo-second-order ( = 1) model and the Langmuir isotherm. There was no competition between MB and Pb in binary solutions, indicating that MB and Pb did not influence each other as a result of their different adsorption mechanisms (electrostatic interaction for Pb and hydrogen bonding for MB). This illustrates monolayer sorption on the FeO/BC/MXene composite governed by chemical adsorption. Thermodynamic investigations indicated that the sorption process was spontaneous and exothermic at 293-313 K, suggesting that it is feasible for practical applications. FeO/BC/MXene can selectively adsorb Pb ions and MB from wastewater containing multiple interfering metal ions. The sorption capacities were still high after five reusability experiments. This work provides a novel FeO/BC/MXene composite for the rapid and efficient removal of Pb and MB.