Performance Evaluation of Magnetic-Multiwalled Carbon Nanotube in Removal of 2,4-DNP from Aqueous Solutions and Determining Toxicity Reduction

In Iran, due to vast development of different chemical and petrochemical industries and water resource pollution to refractory organic matters, using a costeffective method for the removal of those pollutant from drinking water. The aim of this study was to evaluate the performance of magnetic-multiwalled carbon nanotube for the removal of 2,4- dinitrophenol from aquoeous solutions and deteremining toxicity reduction of the effluent.
Adsorption experiments were conducted in a batch system. Magnetic-multiwalled carbon nanotubes were synthesized by co-precipitation method. Variables of contact time (0-90 min), pH (3,5, 7, 9, 11), pollutant concentration (10-100 mg/L) and adsorbent concentration (1-2.5 g/L) were considered. For the determination of toxicity reduction of the effluent, the Bioassay tests were applied by using Daphnia magna which toxicity of 48h and 96 h were obtained.
Results were showed that the maximum removal of 92.97% in the contact time of 90 min were obtained in pH=7, pollutant concentration of 10 mg/L and adsorption concentration of 2.5 g/L. The adsorption process was in accordance with Freundlich isotherm which showed non-uniform and multi-layered adsorption on the surface of the adsorbent and heterogeneous adsorption. The results of the toxicity of 2,4-DNP, before the adsorption process, on the Daphnia magna organism showed that the lethal concentration (LC50) 48h and 96 h of the raw wastewater was 42 and 38 percent (4.2 and 3.8 mg/L), respectively.
The magnetic-multiwalled carbon nanotube adsorbent could be a proper choice for removal of 2,4-DNP, due to high removal efficiency, recyclability, reusability and activity in neutral pH.