Evaluation on the Application of Immobilized Stereospermum kunthianum Stem-bark for the Removal of Pd2+, Cd2+, Cr2+, Fe2+, Zn2+, Mn2+ in Aqueous Solution

This research studied the sorption capacity of Stereospermum kunthianum plant for the removal of heavy metal ions from waste water. The plant stem-bark was immobilized by entrapping or caging the bio-sorbent within a polymeric matrix of calcium- alginate to produce immobilized stem-bark (IMSB). The sorption efficiencies of heavy metals (Zn2+, Pb2+, Cd2+, Mn2+, Fe2+ and Cr2+) were investigated in aqueous solution using the IMSB and the residual metal ions in solution was determined using atomic absorption spectrophotometer (AAS). The effect of various parameters such as contact time, pH, ionic strength, initial metal ion concentration and temperature variation on the sorption of the above metal ions were investigated using batch experiments. The result obtained showed that the sorption efficiencies of Zn2+, Pb2+, Cr2+, Cd2+, Mn2+ and Fe2+ by IMSB were 91.60%, 97.85%, 78.46%, 85.08%, 65.20%, and 78.52% respectively. Result also shows that metal ion sorption increases with increase in contact time; initial metal ion concentration and increase in pH, and decreases with increase in temperature and ionic strength. In view of the above result, the abundant but presently wasted Stereospermum kunthianum plant can be used as a low-cost sorbent for the removal of heavy metal ions in waste water.