Biosorption of copper and nickel ions using Pseudomonas sp. in single and binary metal systems

Abstract

Pseudomonas sp. is a common kind of bacteria. In order to confirm whether Pseudomonas sp. can be used to remove the heavy metals from wastewater, the study investigated its adsorption capacity in single and Cu2+–Ni2+ binary systems. Experimental parameters affecting the metal uptake by Pseudomonas sp. in single system, such as initial solution pH, initial metal concentration, and contact time, were investigated. In single system, the highest adsorption yields of Cu2+ and Ni2+ by the Pseudomonas sp. were 44.78 mg Cu2+ g−1 and 336.84 mg Ni2+ g−1, respectively, at the optimum conditions for each metal. The kinetic and equilibrium experimental data of Cu2+ and Ni2+ ions in the single systems could be successfully described by Langmuir and Freundlich isotherms, whereas the adsorption isotherm was better described by a Langmuir model rather than a Freundlich model. In Cu2+–Ni2+ binary systems, the maximum adsorption amount of Cu2+ and Ni2+ were 38.62 mg Cu2+ g−1 and 323.47 mg Ni2+ g−1, respectively. It obviously showed that the adsorption capacities of the two ions were suppressed, and nickel ion was dominant in the competitive adsorption. Besides, the equilibrium data for the interaction of the metal ions in the binary system could well be described by the Langmuir competitive model. The result gained from these studies indicated that Pseudomonas sp. had the potential to remove Cu2+ and Ni2+ ions from wastewaters.