Bioabsorption of Maize Cob and its Derivative in the Elimination of Heavy Metals from Waste Water in Some Local Government Areas of Kaduna State, Nigeria

Industrial waste water is a significant cause of water pollution. Many health challenges can be linked to high intake of heavy metals directly or indirectly into the body system beyond which is required to function adequately. This study evaluated the bioabsorption potentials of Maize Cob (MC), Maize Cob Charcoal (MCC), and Ethylenediamine-disuccinate treated Maize Cob (ETMC) in the elimination of heavy metals from industrial waste water in Kaduna South and Chikun Local Government Areas. Industrial waste water samples were collected from Defence Industries Corporation of Nigeria (DICON), Bam Paint Industry (BAM-PAINT), Chellco Industry (CHELLCO) and Nigerian Breweries plc (NBC). Heavy metals were analyzed using Atomic Absorption Spectrophotometry (AAS). MC, MCC and ETMC were used to treat the industrial waste water through Batch sorption experiment at 0.42mm particle size. Zinc (Zn2+), Copper (Cu2+), Cadmium (Cd2+), Nickel (Ni2+) and Lead (Pb2+) were the detected at different concentrations across the samples. The results showed that concentration of Zn2+ ion present in the study areas ranged from 0.442 ± 0.005 to 3.943 ± 0.031mg/g. Cu2+ ion ranged from 0.226 ± 0.003 to 9.730 ± 0.001 mg/g, Cd2+ (-0.040± 0.005 to 0.624 ± 0.003 mg/g), Ni2+ (0.184 ± 0.004 to 12.096 ± 0.003 mg/g) and Pb2+ (-0.142± 0.003 to 1.128 ± 0.002 mg/g). Heavy metal absorption efficiencies by MC differ significantly (p < 0.05). MC had the highest adsorption rate (92%) for Zn2+ ion in DICON Company waste water. Cu2+ was reduced by 40% in waste water from BAM-PAINT Company, 94% for Cd2+ ion in NBC waste water, 72% for Ni2+ and 98% of Pb2+ in NBC waste water. Heavy metal removal efficiency after using MCC showed significant difference (p < 0.05) in the heavy metals adsorption rate. There was 85% reduction in the concentration of Zn2+ and 40% of Ni2+ in industrial waste water from DICON Company. The absorbent was most effective in reducing the concentration of Cu2+ ion present in NBC by 187% and 154% of Cd2+ ion in sample from BAM-PAINT Company, while, Ni2+ and Pb2+ had reduction rate of 60% and 95% at DICON and NBC respectively. ETMC drastically reduced the concentration of Zn2+ ions from to -604.533 ± 2.512 mg/g in CHELLCO industry and Cu2+ions to -9.567 ± 0.351 mg/g in BAM-PAINT waste water. Therefore, it can be concluded that Maize Cob, Maize Cob Charcoal and Ethylene diamine disuccinic treated maize cob are effective absorbent for eliminating lead, zinc, cadmium, nickel and copper from waste water.