Water is a necessary and planned resource that ensures economic and social development. The quick growth of the economy, remarkable growth of population, steady growth of several industries, and human activities are sources of environmental pollution, especially water pollution. Different industries, involving electrification, tanneries, mining, metal processing, smelting, battery production, etc., have generated huge amount of heavy metals in wastewater.^1–4 Heavy metal wastewater is present in the environment in the form of direct or indirect approaches, such as river sediment, rainfall-runoff, domestic, industrial, and agricultural effluents, and atmospheric deposition.^5–8 Bulgariu et al. presented that numerous heavy metals are carcinogenic and toxic.⁹ Nezamzadeh et al. identified that heavy metal pollution has already been extremely risky to the environment.¹⁰ Lead is the most ordinary heavy metal in waste aqueous media. Excessive uptake of lead can induce intense injury to the kidney, nervous system, reproductive system, brain, and liver.^11,12

Thus, the elimination of Pb from contaminated water is an essential job. Different approaches, such as electrochemical separation, ion exchange, adsorption, membrane process, distillation, advanced oxidation, and solvent extraction, have been reported for the elimination of Pb²⁺ ions.^13–16 All the above-mentioned approaches have certain disadvantages, such as high cost, difficulty of operation, and energy intensity. Among the above approaches, the adsorption approach has received tremendous attention due to its high efficiency, simplicity, ease of operation, cost efficiency, and high flexibility.^17,18 The choice of sorbents is a vital parameter in the sorption approach. Several sorbents, such as biomaterials, zeolites, metal oxides, activated carbon, bio-sorbents, and activated alumina clay, have been extensively utilized for Pb²⁺ ion removal.^19–21 Furthermore, all of these traditional sorbents exhibited low adsorption capacity for Pb removal.²²

Two-dimensional materials have been utilized to remove heavy metals, dyes, and pharmaceuticals from wastewater via the adsorption technique. MXene is a well-known 2D material.²³ MXene contains transition metal nitrides, carbides, and carbonitrides and is a novel 2D material family that has drawn considerable attention these days. M_n+1X_n is the general formula for MXene, where n = 1, 2, 3, and M correspond to transition metals like Nb, V, Ti, Sc, Mo, Zr, Ta, and Hf while X is N or C.²⁴ MXenes are mostly prepared using selectively etching Al from the MAX phase, where the A layers represent Ga, Al, or Si. After etching, the surface of MXene becomes rich in –F, –O, and –OH. As an adsorbent having the ability for environmental remediation, its outer surface has –F, –O, and –OH groups, so it can have better dispersibility in aqueous media and easily attract or bind the cationic heavy metals in water via electrostatic sorption.^25–27 For instance, Ying et al. introduced 2D MXene nanosheets for the removal of chromium.²⁸ Dong et al. reported the preparation of MXene/Alginate composite and investigated their adsorption activity against lead and copper. The prepared composite indicated an enhancement in adsorption capacity due to the increase in the active adsorption site.²⁹ Zhang et al. reported the synthesis of MXene@Fe₃O₄ composite and utilized it for the removal of methylene blue.³⁰

Metal–organic frameworks are porous and crystalline structures consisting of a 3D network of cationic metal held in a specific position using organic molecules by coordination interaction, producing a cage-like network.³¹ Because of their hollow, highly organized structure, MOFs have an impressively high internal surface area that is more than that of activated carbons, ranging from 1000 to 10 000 m² g⁻¹. Many MOFs show excellent chemical stability in the presence of an extreme environment.³² Additionally, MOFs can be prepared at a low cost and simple approach on a large level. The tunable physiochemical traits, along with highly organized material, make MOFs a favorable sorbent that is efficient in heavy metal ion removal.³³ Xu et al. described the synthesis of Zn/Zr-based MOFs by reaction of carboxyl/thiol or carboxyl/thiol-ether, which exhibited favorable adsorption performance for heavy metals (He et al., 2011). Similarly, an azine-decorated Zn(ii) MOF was investigated as a sorbent to trap heavy metal ions (Tahmasebi et al., 2015). However, these virgin MOFs exhibited low adsorption capacity. To increase the adsorption capacity of heavy metal ions from drinking water, several MOFs have been modified by different researchers and scientists (Nozohour Yazdi et al., 2018) (Yu et al., 2018).³⁴ Thus, initially, in the current study, THC MOFs were synthesized, and then, the prepared THC MOFs were functionalized using MXene to increase the adsorption capacity. Herein, the basic objective of this work is to rapidly remove lead from wastewater to make it potable using a novel adsorbent. In order to prepare such adsorbents, first, we prepared Fe-THC MOFs from tetrahydrocannabinol, and then we prepared MXene from Ti₃AlC₂via a wet chemical approach. Then, two different types of materials were combined to create novel Fe-THC/MXene composites as an adsorbent. The prepared THC/MXene composites exhibited excellent adsorption capacity against lead. Furthermore, suitable sorption conditions such as initial lead dosage, sorbent concentration, adsorption time, temperature, and pH were investigated carefully. The sorption kinetic and isotherm models were utilized to investigate adsorption phenomena, and FTIR, EDX, XRD, and XPS spectra were utilized to explore the adsorption mechanism.