Adsorptive Removal of Metal (Cu++, Co++ and NI++) Ions from Aqueou Solution Over Powdered Activated Carbon: A Kinetic and Equilibrium Study

Water pollution is one of the most undesirable environmental problems in the world and it requires solutions. Textile industries produce a lot of wastewater, which contains a number of contaminants, including acidic or caustic dissolved solids, toxic compounds and many different dyes. Many of the heavy metals are hazardous and may affect aquatic life causing various diseases and disorders. The aim of the present work is to explore the possibility of using these carbonaceous materials as low-cost adsorbents. The removal of heavy metals from industrial effluents is a major priority before their discharge on environment. Developed processes require expensive and in many cases advanced technologies. Commercially activated carbon is more costly, such that cost of investment may not permit to use effectively. We report that the low cost carbon system, which were obtained from used up commercial batteries Nippo and BPL are used for the effective adsorption of heavy metal cations, Cu++, Ni++ and Co++, colouring metal ions also adsorb active low molecular weight organic compounds like phenols, carboxylic acid and phenyl acetic acid. Carbon dose required for maximum percentage of adsorption was found as 55.8, 50.5 and 54.2 in the case of Cu++, Ni++ and Co++ ions respectively per gram of isotherm constants after studying Langmuir and Freundlich method were determined. Plot of metal ion adsorbed in mg vs. equilibrium metal concentration are linear at low concentration and flat at higher concentration. This supports the Langmuir theory that the intermolecular forces between the sorbate and sorbent would not be significant beyond the first sorbed layer and that a portion of the sorbate molecules adheres, while the remainder renounce into the liquid phase. Under the kinetics, the plots of the concentration of metal ions i.e. log [1-u (t)] vs. contact time are linear, indicates that the sorption could be a first order reversible kinetics.