In this study, quartz sand (QS) incorporated into a crosslinked chitosan-glutaraldehyde matrix (QS@Ch-Glu) was prepared and employed as an efficient adsorbent for the elimination of Orange G (OG) dye from water. The sorption process is adequately described by the pseudo-second order kinetic model and the Langmuir isotherm model with maximum adsorption capacities of 172.65, 188.18, and 206.65mg/g at 25, 35, and 45°C, respectively. A statistical physics model was adopted to elucidate the adsorption mechanism of OG on QS@Ch-Glu. Calculated thermodynamic factors revealed that the adsorption of OG is endothermic, spontaneous, and occurs via physical interactions. Overall, the proposed adsorption mechanism was based on electrostatic attractions, n-π stacking interaction, hydrogen bonding interaction, and Yoshida hydrogen bonding. The adsorption rate of QS@Ch-Glu was still above 95% even after 6 cycles of adsorption and desorption. Furthermore, QS@Ch-Glu demonstrated high efficiency in real water samples. All these findings demonstrate that QS@Ch-Glu is qualified for practical applications. Display omitted •QS@Ch-Glu composite was synthesized by incorporation of quartz sand into glutaraldehyde crosslinked chitosan matrix.•Integration of quartz sand into glutaraldehyde crosslinked chitosan was confirmed by FTIR studies.•The regeneration process could be repeated at least six times.•Selectivity, and real water experiments were investigated to evaluate the suitability of QS@Ch-Glu in partical applications.•Statistical physics modeling was used to elucidate the adsorption mechanism of orange G on QS@Ch-Glu.