Artocarpus altilis proving its worth in toxic metal removal from the environment

Nuts of breadfruit tree (Artocarpus altilis) obtained from Ugbowo Campus of University of Benin, Benin City, were dehusked and the husk thoroughly washed with distilled water, air-dried, pulverized and sieved to obtain the particulate sizes of 63 êm, 300 êm and 600 êm. These particulate sizes were oven-dried at 105oC to constant weight and preserved in a desiccator. The pulverized husk hereafter was referred to as adsorbent. Adsorbent (1.0g) of each particulate size was weighed into 100cm3 conical flask containing 50cm3 of 2.0, 4.0, 6.0, 8.0 and 10.0mgL-1 Pb2+ ions, respectively. These mixtures were shaken for 30 min after which they were filtered and the filtrate used for Atomic Absorption Spectrophotometric (AAS) analysis. The same process was repeated using Cd2+ and Ni2+ ions, respectively. The effects of particulate size (surface area), temperature, initial metal ion (adsorbate) concentration and pH, on the extent of sorption, were studied; the infrared (IR) spectra of the adsorbent was also studied. Results indicate that sorption capacity is best at pH 4.0 for all metal ions (Cd2+, Pb2+ and Ni2+) studied. The effect of temperature revealed that maximum sorption occurs at 29oC compared to other temperatures of 60oC and 90oC. There was a general increase in adsorption of Cd2+, Pb2+, and Ni2+, ions as their initial concentrations increased. The adsorbent particulate size of 63 êm had the greatest adsorptive capacity compared to other sizes. IR analysis of the adsorbent suggested the presence of C = O, OH, N-H, N = O, C N, and COOH functional groups.