Genson Murithi; Karanja wa Thiong'o; Wachira Muthengia
Abstract: The adsorption potential of pig bone char (PBC), rice husk ash (RHA) and water hyacinth biomass (WHB) composite mixture to remove lead (II) ions from industrial waste water was investigated using a fixed bed column. The effects of bed height (2-10 cm), flow rate (5-10 mL/min) mL and feed concentration on the breakthrough characteristics of the column were determined. The highest bed capacity of 476.2 mg/g was obtained using 10-cm bed height, 12 feed concentration and 5 mL/min flow rate. The result indicated that adsorption capacity increased with increase in the inlet ion concentration and bed height and decreased with increase in flow rate. Increasing the flow rate resulted in a shorter time of bed saturation. Adsorption data was fitted to Adam-Bohart, Thomas and Yoon-Nelson models. The data was well fitted by the Thomas and Yoon-Nelson models with correlation coefficient R2 0.96 and for Adam-Bohart model, R2 0.94. It was noted that the rate constant for the Yoon-Nelson model increased with increase in flow rate, initial ion concentration and bed height. The breakthrough and exhaust times between the cycles did not differ significantly at 95 % confidence level. The adsorption of PBC/RHA/WHB had approximately 20 % more adsorption capacity than the commercially available materials.
Keywords: Adsorption; Pig Bone char; Fixed bed column; lead (II) ions, Rice husks ash, water hyacinth biomass, wastewater