A natural biosorbent prepared from wheat bran (WB) and multiple quaternary ammonium salts (MQAS) was used to remove dye (AR-18) from aqueous solution. The adsorption kinetics and thermodynamic mechanism of the adsorption of AR-18 on MQAS-WB were also examined. Results reveal that adsorption isotherm data can be well described by Langmuir model. The calculated thermodynamic parameters indicate that the adsorption is exothermic and spontaneous. The adsorption kinetics follows the pseudo-second-order model. MQAS-WB shows potential for large-scale wastewater treatment. Dynamic adsorption studies reveal that the dye removal efficiency of the packing column of MQAS-WB is higher than that of raw WB.