REMOVAL OF CR (VI) FROM AQUEOUS SOLUTION BY ADSORPTION ON POLYANILINE-ACTIVATED CARBON ADSORBENT

Heavy metals, such as lead, chromium and nickel, are known to be major environmental pollutants and highly toxic to humans and other organisms, even at low concentrations. Chromium is widely used in many industries in various forms, but chromium (VI) is considered a denite carcinogen and, thus, should be almost completely removed from industrial wastewater to meet environmental laws and regulations. Many techniques are used to treat wastewater, containing Cr (VI), including; reduction followed by precipitation, Ion exchange, adsorption by clay or activated carbon and reverse osmosis. However, these processes often produce too much sludge, or are inecient when large volumes of wastewater are involved or do not meet environmental standards. Adsorption is another eective method with very few disadvantages compared to others. In recent years, synthetic polymers have been considered as quality adsorbents for removal of Cr(VI) from wastewater. The aim of this study is to investigate the possibility of absorption of chromium from aqueous solutions by a new and innovative adsorbent produced from Polyaniline-activated carbon. The eect of various operative parameters on the adsorption of Cr (VI) was studied. Experiments were carried in batch mode and the eect of variables, such as the initial concentration of Cr (VI), amount of adsorbent, adsorption time, and initial pH value and temperature, were studied. The maximum adsorption of Cr (VI) was obtained at 400C, with an initial concentration of 15 ppm, with an initial solution pH of less than 5 and addition of 10 g/lit Polyaniline-activated carbon. Recovery of the adsorbent was carried out by desorption with nitric acid, where 2 M nitric acid was used to recover 83% of Cr (VI). The results indicate that Polyaniline-Activated carbon can be eectively used in the treatment of wastewater containing Cr (VI). Kinetic studies on adsorption behavior closely followed the \Langmuir adsorption isotherm" model for a single layer.