<p>Benzoic acid (BA) shares structural and amphiphilic characteristics with numerous other contaminants of concern. Because of BA harmful effects, wastewater treatment is so important before releasing such pollutant to the water bodies however its removal is not so easy. In this study synthesized green magnetic-based nanocomposites in the absence and presence of cetyltrimethylammonium bromide, as an efficient adsorbent, was compared for removal of BA from water samples (nanosorbents include: Fe₃O₄, CTAB-Fe₃O₄, Ag/Fe₃O₄, CTAB-Ag/Fe₃O₄) which show a very high adsorption capacity. Magnetic-based nanocomposites were prepared by easily green co-precipitation method and characterized by FESEM, XRD, FTIR and BET measurements. Considering the effect of initial pH, amount of adsorbent, dosage of surfactant, amount and kind of elution, and contact time for adsorption and desorption processes have been investigated in order to find the optimum adsorption/desorption conditions. Results showed that synthesized nanocomposites outperform other adsorbents and are a valuable option for rapid and economic removal of low concentrations of BA as a small contamination in a wastewater treatment. The high adsorption capacity was evaluated using the Langmuir adsorption isotherm model (q_max) about 909.1 mg.g^− 1 of the adsorbent.</p>