<p>The adsorption potential of the light fraction of Padma River sand for the removal of hexavalent chromium (Cr(VI)) from aqueous solutions was investigated, with surface properties characterized using Fourier Transform Infrared Spectroscopy (FTIR) and methylene blue (MB) dye adsorption for specific surface area (SSA) estimation. FTIR analysis confirmed the presence of functional groups including Si–O–Si, Al–O, and OH, with observable shifts and the emergence of new Cr–O vibrations at approximately 930&#xa0;cm⁻¹ following adsorption, indicating effective binding of Cr(VI) species. The MB adsorption method determined a monolayer capacity (qₘ) of 4.846&#xa0;mg/g and an SSA of 11.86 m²/g, demonstrating the availability of active adsorption sites. Batch adsorption experiments identified optimal Cr(VI) removal at pH 2, with a maximum capacity of 4.9128&#xa0;mg/g. Adsorption kinetics conformed to a pseudo-second-order model (<i>R</i>² = 0.9998), while equilibrium data were consistent with the Langmuir model (<i>R</i>² = 0.9991), supporting monolayer chemisorption. Thermodynamic analysis (ΔG° = –4.02&#xa0;kJ/mol; ΔH° = –19.62&#xa0;kJ/mol; ΔS° = –52.71&#xa0;J/mol·K) indicated a spontaneous and exothermic process. Collectively, these findings demonstrate that the light fraction of Padma River sand is a promising, environmentally friendly, and cost-effective adsorbent for Cr(VI) remediation in water treatment applications.</p> Graphical Abstract <p></p>