Spatial interpolation and isotherms studies for groundwater remediation utilizing Be/CNTs@Alg nanocomposite material; case study: Beni-Suef aquifer floodplain

Abstract In this research, a nanocomposite material, Bentonite cross-linked multi-walled carbon nanotubes@soduim alginate (Be/CNTs@Alg), was synthesized by impregnating multi walled carbon nanotubes (CNTs) using a mixture of sodium alginate (Alg) on the surface of activated bentonite (Be). The composite was employed as a sorbent material to effectively remove Fe(II) and Mn(II) from the groundwater. Numerous characterization methods such as X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Brauner-Emmett-Teller (BET) analysis were employed. The study evaluated the influence of various factors including temperature, adsorbent dosage, contact time, initial metal ion concentration, agitation rate, and pH on Fe(II) and Mn(II) adsorption. Results showed that CNTs penetrated the bentonite interlayers. The nanocomposite had a BET surface area of 40.885 m²/g. The adsorption of both metal ions was fast and highly pH-dependent, with monolayer adsorption capacities calculated from the linear fitting were of 7.6277 mg/g for Fe(II) and 6.1009 mg/g for Mn(II), and from nonlinear fitting were of 7.929 mg/g for Fe(II) and 7.39137 mg/g for Mn(II) at 25 °C. Kinetic data fit the PSO model, and thermodynamic analysis indicated that the process was spontaneous and endothermic. The spatial interpolation of Fe and Mn proves effective for visualizing and managing Beni-Suef Quaternary Aquifer quality. The findings highlight the potential of the Be/CNTs@Alg composite for the uptake of Fe(II) and Mn(II), and its possible application in the decontamination of other pollutants from real groundwater.