Benzene removal from aqueous solutions was evaluated using Fe3O4 nano magnetic particles (NM) in continuous condition. A 44 factorial design including initial benzene concentration, NM dose, contact time and pH was investigated in 16 experiments (Taguchi OA design). The results indicated that all factors were significant and the optimum condition was: pH 8, NM dose of 2000 mg·L-1, benzene concentrations of 100 mg·L-1 and contact time of 14 min. The maximum benzene uptake and distribution ratio in the optimum situation were 49.4 mg·g-1 and 38.4 L·g-1, respectively. The nano particles were shown to capture 98.7% of the benzene in optimum batch condition and 94.5% in continuous condition. The isotherm data proved that the Brunauer-Emmett-Teller model fit more closely and produced an isotherm constant (b) less than one, indicating favorable adsorption. Regeneration studies verified that the benzene adsorbed by the NM could be easily desorbed by temperature, and thereby, NM can be employed repeatedly in water and wastewater management. |