title: Ni2+ removal and recovery from electroplating effluent by Pseudomonas putida 5-x cell biomass.
abstract: Ni2+ and Cu2+ are the major heavy metal ions in electroplating wastewater of Hong Kong. In the present study, Pseudomonas putida 5-x cell biomass was used to remove Ni2+ from electroplating effluent. Ni2+ adsorption capacity of P. putida 5-x cell biomass cultured in sulphate-limiting medium was found to be minimum in early logarithmic growth phase, and maximum of 28.1 mg g(-1) in late stationary growth phase. Pretreated cells by 0.1 mol L(-1) HCl could greatly enhance the Ni2+ adsorption capacity of cell biomass from 28.1 to 36.7 mg g(-1) and had no significant effect on biomass loss. The adsorption process of P. putida 5-x fresh cells and pretreated cell all could be expressed with Freundlich isotherm. TEM analyses indicated that acidic pretreatment degraded the superficial layer-capsule outside of the fresh cell to improve the adsorption capacity of cell to Ni2+. The Ni2+ bound by P. putida 5-x cell biomass could be efficiently recovered using 0.1 mol L(-1) HCl, and the cell biomass could be reused at least five cycles for Ni2+ removal and recovery with 93% above removal efficiency and 98% above recovery rate. Owing to the Cu2+ presented in electroplating wastewater inhibiting Ni2+ adsorption process by P. putida 5-x cell biomass, two-stage biosorption processes should be designed to remove and recover Cu2+ and Ni2+ sequentially from electroplating effluent.
authors.affiliation: Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Hong Kong. 99900170r@polyu.edu.hk
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.forename: H
authors.initials: H
authors.lastname: Chua
authors.forename: P K
authors.initials: PK
authors.lastname: Wong
authors.forename: W H
authors.initials: WH
authors.lastname: Lo
authors.forename: P H F
authors.initials: PH
authors.lastname: Yu
mesh_terms: D000327:Adsorption; D001673:Biodegradation, Environmental; D018533:Biomass; D004595:Electroplating; D009532:Nickel / Q000737:chemistry / Q000302:isolation & purification*; D016958:Pseudomonas putida / Q000502:physiology*; D014865:Waste Disposal, Fluid; D018508:Water Purification / Q000379:methods*
chemical_list: D009532:Nickel