Biosorption and Bioaccumulation Capacity of Arthospiraplatensis toward Europium Ions

Abstract

Europium recovery from wastewater is determined by its high significance for industry and toxicity for living organisms. The capacity of cyanobacteria Arthospira platensis (Spirulina) to remove Eu(III) through biosorption and bioaccumulation was evaluated. In biosorption experiments, the effects of four variables pH, metal concentration, time, and temperature on metal removal were studied. In bioaccumulation experiments, the effect of Eu(III) concentrations on biomass bioaccumulation capacity and biochemical composition was assessed. The efficiency of Eu(III) uptake in both experiments was determined using ICP-AES techniques. Maximum biosorption of Eu(III) was achieved at pH 3.0. Equilibrium data fitted well with the Langmuir and Freundlich models, with maximum adsorption capacity of 89.5 mg/g. The pseudo-first-, pseudo-second-order, and Elovich models were found to correlate well with the experimental data. According to thermodynamic studies the sorption was feasible, spontaneous, and endothermic in nature. At addition of Eu(III) ions in the cultivation medium in concentrations of 10–30 mg/L, its accumulation in biomass was 9.8–29.8 mg/g (removal efficiency constituting 98–99%). Eu(III) did not affect productivity and content of carbohydrates and pigments in biomass but led to the decrease of the content of protein and an increase in the amount of MDA. The high Eu(III) biosorption and bioaccumulation efficiency of Arthrospira platensis may constitute an effective and eco-friendly strategy to recover it from contaminated environment.

Application of Cyanobacteria Arthospira platensis for Bioremediation of Erbium-Contaminated Wastewater

“…The pseudo-first-order model assumes that the rate of sorption sites filling is proportional to the number of unoccupied sites [ 30 ]. The applicability of the pseudo-first-order model for other rare earth elements sorption by spirulina biomass was shown previously [ 17 ]. The adsorption of Er(III) onto RH activated carbon was better described by the pseudo-second-order kinetic model [ 1 ].…”

“…Spirulina can react very differently to the presence of rare earth elements in the cultivation medium, and the effect can range from inhibition to neutral and up to a stimulating one [ 17 , 34 , 35 , 36 , 37 , 38 ]. The effect of Er(III) observed in the present study was very similar to that of Sm, Tb and Nd, which in concentrations of 10–30 mg/L did not affect the amount of spirulina biomass.…”

“…0; Na 2 HPO 4 —0.2; MgSO 4 ·7H 2 O—0.2; in 1 mL/L of solution of microelements (mg/L): H 3 BO 3 —2.86; MnCl 2 ·4H 2 O—1.81; CuSO 4 ·5H 2 O—0.08; MoO 3 —0.000015; FeEDTA—1 mL/L, was prepared. Biomass was grown at temperature of 25–28 °C, illumination ~37 µM photons/m 2 /s and pH 8–9 during first two days of growth, and a temperature of 30–32 °C, pH −9–10 and illumination ~55 µM photons/m 2 /s throughout next four days of cultivation [ 17 ].…”

“…For biosorption experiments, biomass cultivated according to Yushin et al [ 17 ] was filtrated, dried and homogenized. Then 100 mg of the biosorbent were added to a 20 mL volume of erbium solution in 50 mL conical flasks.…”

“…At the end of experiments the biomass was separated from supernatant by filtration, and total erbium concentration in solutions was determined using ICP-OES PlasmaQuant PQ 9000 Elite spectrometer (Analytik Jena, Jena, Germany). The biomass sorption capacity (mg/g) and the efficiency of Er(III) removal (%) were calculated by formulas described elsewhere [ 17 ]. where V is the volume of the solution, ml; C i and C f are the initial and final metal concentrations in mg/L; and m is the mass of sorbent in g.…”