Abstract:
It was aimed to synthesize an adsorbent for
fluoride and hardness removal using a nanoclay-biochar
composite from unrefined Montmorillonite (MMT) clay
from the Murunkan in Mannar, Sri Lanka. Fourier
Transform Infrared Spectroscopy (FTIR), X-Ray
Diffraction (XRD), X-Ray Fluorescence (XRF), Scanning
Electron Microscope (SEM), and Thermal Gravimetric
Analysis (TGA) were employed to characterize the
materials. FTIR, XRD, and TGA analyses indicated the
presence of MMT clay mineral in the sample. The SEM
image of the composite confirmed the successful binding
of MMT onto the biochar through a flaky appearance
along the porous morphology. Further, the surface
texture of clay and biochar could support hardness and
fluoride removal by enhancing adsorption. The results
obtained from CHN analysis show that the biochar
sample was rich in carbon, which helps in the sorption of
hardness and fluoride. The adsorption isotherm data of
all the adsorbents were well fitted to the Temkin isotherm
model, suggesting that the removal of hardness and
fluoride onto the adsorbent indicates a heat of sorption.
The kinetic adsorption data of all the adsorbents were
well fitted to the pseudo-first-order kinetic model,
indicating the dominant contribution of the physisorption
mechanism. However, since the measured adsorption was
minimal, a modification to the nanoclay-biochar
composite is required for higher sorption efficiency by
enhancing the active sites on sorbents to purify
groundwater that con
