Natural and anthropogenic activities generally result to large production of heavy metals. These heavy metals produced are indiscriminately discharged into rivers and other water bodies. Wastewater treatment of industrial effluents become very necessary due to toxic effect of heavy metal pollutants and its indirect effect pose to human health. Banana peel, an agricultural waste biomass can be used to produce bio-sorbent for adsorption of heavy metals from industrial wastewater. This study focused on the production of chemically modified activated carbon using various concentrations of phosphoric acid for removal of lead and zinc metals from aqueous solution. Activated carbon was produced from waste banana peel through thermal pretreatment at temperature of 450℃ preceding chemical modification with different concentrations of phosphoric acid of 0.5 M, 1.0 M and 1.5 M. The three different concentrations of the phosphoric acids represent sample X, Y and Z respectively. To study the adsorption efficiency of chemically modified activated carbon using different concentrations of phosphoric acid, batch experiments were conducted on chemically modified samples to assess the adsorption of lead (II) and zinc metals from aqueous solution. The three adsorbents were interacted with varying parameters such as effect of initial concentration of lead and zinc metal of concentration of 10 mg/L and 2 mg/L respectively. Based on batch experiments conducted, results indicated that adsorbent dose, pH, initial concentration as well as contact time are important factors influencing lead (II) and Zinc metals adsorption from aqueous solutions. Percentage adsorption of lead (II) and zinc metals was above 80 % for all three chemically modified adsorbents investigated. The adsorption capacities of the adsorbents under study showed high adsorption capacity for both zinc and lead metals. This implies that sample X, Y and Z are good adsorbents for adsorption of both zinc and lead metals in an aqueous solution.