Effective Parameters on Removal of Rhodamine B from Colored Wastewater by Nano polyaniline/Sawdust Composite

Background and purpose: Contamination of groundwater with colored and toxic wastewater causes many environmental problems and has adverse effects on human health. This study aimed at coating a nano polyaniline polymer layer on the surface of sawdust and preparing polyaniline sawdust composite (Pan/SD) via chemical polymerization of aniline monomer onto sawdust in aqueous solutions and removal of Rhodamine B dye. Materials and methods: In an experimental study, polyaniline was synthesized by oxidation with ammonium persulfate. In order to find out the optimum dye removal conditions, the effects of some major parameters, including pH, contact time, initial dye concentration, and absorbent dose were studied. For treatment of the adsorption data, both Langmuir and Freundlich isotherm were employed. Also, Thermodynamic and Kinetic studies were performed. Results: The study showed that the aniline/sawdust nanocomposite can absorb more than 94% of  Rhodamine B in Rhodamine B concentration of 10 mgL-1, optimum adsorbent 1 gL-1, pH = 5, and contact time 5h. Absorption data were more fitted with Freundlich isotherm. Thermodynamic studies showed that the removed dye was spontaneous, endothermic and chemical sorption that followed second order kinetic model. Conclusion: The adsorbent introduced here, is an insoluble absorbent in water without secondary pollution and a very efficient adsorbent for removal of Rhodamine B from aqueous solutions and a layer of conductive nano-polymer onto the sawdust can remove a high percentage of Rhodamine B from aqueous environments.