Ni2+ removal and recovery from electroplating effluent by Pseudomonas putida 5-x cell biomass.
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.
Wang
L
L
Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Hong Kong. 99900170r@polyu.edu.hk
Chua
H
H
Wong
P K
PK
Lo
W H
WH
Yu
P H F
PH
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*
D009532:Nickel