Biosorption of nickel, cobalt, zinc and copper ions by Serratia marcescens strain 16 in mono and multimetallic systems

Abstract

The metallurgical industry is one of the main sources of heavy metal pollution, which represents a severe threat to life. Metals can be removed from aqueous solutions by using microbial biomasses. This paper analyses the heavy metal biosorption capacity of Serratia marcescens strain 16 in single and multimetallic systems. The results obtained show that Co(II), Ni(II) and Zn(II) biosorption in monometallic systems is two to three times higher than in the presence of bi-metallic and multimetallic solutions. Fourier transform infrared spectroscopy confirmed that carbonyl, carboxyl and hydroxyl were the main functional groups, as well as the amide bands I and II involved in metal uptake, which are present in external structures of the bacterial cell. The results obtained demonstrated the viability of S. marcescens strain 16 as a biosorbent for the design of eco-friendly technologies for the treatment of waste liquor.

Keywords: Biosorption; Heavy metals; Multimetallic systems; Serratia marcescens; Waste liquor (WL).

Fig. 1

Experimental assembly of 1 L bioreactors. 1, 4: temperature control system, 2: 1 L reactors; 3, 5: pH electrodes coupled to a multimeter, 6, 7: data loader and storing system

Fig. 2

Biosorption capacity of the metal ions by S. marcescens strain 16 biomass in single and multimetallic systems: initial concentrations 2 mg L⁻¹ Co(II), 25 mg L⁻¹ Ni(II), 9 mg L⁻¹ Cu(II) and 15 mg L⁻¹ Zn(II), contact time 2 h, biomass 0.6 g L⁻¹. Bars represent the average of three determinations ± SD. Different letters correspond to statistically significant differences

Fig. 3

FTIR spectra for heavy metal loaded biomass [Strain 16 + Co(II); Strain 16 + Ni(II); Strain 16 + Cu(II) and Strain 16 + Zn(II)] in contrast with negative control (Strain 16)

Fig. 4

Co(II) and Ni(II) desorption using 0.1 mol L⁻¹ HCl, HNO₃ and H₂SO₄ solutions at different contact times, using 1 ml of eluent agent incubated at 30 °C, 120 rpm

Fig. 5

Biosorption capacity for the metal cations studied in mono- and multimetallic solutions through the four biosorption cycles at bioreactor scale. Bars represent medium values of three determinations ± SD

Fig. 6

Heavy metal removal at bioreactor scale using single or multimetallic systems. Experiments were conducted in 1 L batch bioreactors, at 30 °C, 120 rpm for 2 h