Functionalization of Shorea faguetiana biochar using Fe 2 O 3 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 2+ and the dye methyl blue (MB) by biochar is an ecologically sustainable method to remediate this type of water pollution. We functionalized Shorea faguetiana biochar with Fe 2 O 3 and MXene, resulting in Fe 2 O 3 /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 Fe 2 O 3 /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 2+ and MB at 293 K were 882.76 and 758.03 mg g -1 , respectively. The sorption phenomena obeyed a pseudo-second-order ( R 2 = 1) model and the Langmuir isotherm. There was no competition between MB and Pb 2+ in binary solutions, indicating that MB and Pb 2+ did not influence each other as a result of their different adsorption mechanisms (electrostatic interaction for Pb 2+ and hydrogen bonding for MB). This illustrates monolayer sorption on the Fe 2 O 3 /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. Fe 2 O 3 /BC/MXene can selectively adsorb Pb 2+ 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 Fe 2 O 3 /BC/MXene composite for the rapid and efficient removal of Pb 2+ and MB.