The present work explains the biosorption of malachite green dye from aquatic systems by nano zero valent iron stacked activated carbon (NZVI-AC), which was prepared by dual surface modification strategy. NZVI-AC was characterized by using FTIR, SEM-EDX, XRD and TGA. NZVI-AC exhibited efficient performance in dye biosorption properties. Experimental variables such as time, pH, dye concentration, temperature and biosorbent dosage influenced Langmuir adsorption capacity of 187.3 mg/g. The present biosorption system was best described by pseudo-first order kinetics. The dye was completely knocked out of the solution within 60 min at equilibrium. The thermodynamic behaviour of NZVI-AC was exothermic, feasible and spontaneous. Experimental data was engaged to validate new solid-liquid phase equilibrium model, showing the average absolute relative deviation 7.72%. Hence the procedure was non-toxic, potential to retain biosorbent from the solution, applicable for multiple cycles. In context, NZVI-AC can be recommended for the treatment of dyes from industrial effluent.