Document Type : Research Article
Department of Nanochemical Engineering, Faculty of Advanced Technologies, Shiraz University
A method for treating waste water is suggested which is including dye elimination through contacting with humic acid coated magnetic nano-adsorbent. The nano-adsorbent was modified with humic acid (HA) as a compound having carboxyl, hydroxyl and amine functional groups. HA/Fe3O4 nanoparticles were prepared by a co-precipitation procedure and were characterized using different techniques such as dynamic light scattering (DLS), transmission electron microscopy (TEM), FTIR spectroscopy and X-ray diffraction spectroscopy. Their magnetic properties were investigated by vibrational sample magnetometer (VSM). It was observed that the synthesized nanoparticles have a mean diameter about 15 nm. The effects of several experimental factors such as adsorbent dosage, contact time and initial concentration, on the nano-adsorbent ability for dye removal were investigated. The best results were obtained using 15 mg/ml of nanoparticles and contact time 45 min for methylene blue (MB), 20 mg/ml of nanoparticles and contact time 30 min for indigo carmine (IC) and 5 mg/ml of nanoparticles and contact time 20 min for 4-(2-pyridylazo) resorcinol (PAR). At this condition 96.95, 99.34 and 99.11 % of MB, IC and PAR could be removed from synthetic samples, respectively. Maximum adsorption capacity for MB, IC and PAR were 0.0085, 0.0439 and 0.0307 mmol/gr which were fitted to Langmuir isotherm model. In reuse of nano-asorbents, on average, 94.12% of the dyes were removed from the aqueous medium. These results indicate the efficiency of the synthesized nano-asorbents to remove colored effluents.