Biosorption of strontium from simulated nuclear wastewater by Scenedesmus spinosus under culture conditions: adsorption and bioaccumulation processes and models.

Yuting Guo,Mingxue Liu,Faqin Dong,Ting Huang,Yuanyuan Liu,Hongfu Wei,Wei Zhang,Xiaoqin Nie,Shiyong Sun,Wu Kang

doi:10.3390/ijerph110606099

Abstract

Algae biosorption is an ideal wastewater treatment method when coupled with algae growth and biosorption. The adsorption and bioaccumulation of strontium from simulated nuclear wastewater by Scenedesmus spinosus were investigated in this research. One hundred mL of cultured S. spinosus cells with a dry weight of 1.0 mg in simulated nuclear wastewater were used to analyze the effects on S. spinosus cell growth as well as the adsorption and bioaccumulation characters under conditions of 25 ± 1 °C with approximately 3,000 lux illumination. The results showed that S. spinosus had a highly selective biosorption capacity for strontium, with a maximum bioremoval ratio of 76%. The adsorbed strontium ion on cell walls was approximately 90% of the total adsorbed amount; the bioaccumulation in the cytoplasm varied by approximately10%. The adsorption quantity could be described with an equilibrium isotherm. The pseudo-second-order kinetic model suggested that adsorption was the rate-limiting step of the biosorption process. A new bioaccumulation model with three parameters was proposed and could give a good fit with the experiment data. The results suggested that S. spinosus may be a potential biosorbent for the treatment of nuclear wastewater in culture conditions.

Highlights

The biosorption of heavy metals by living or growing biomasses involves two processes: an initial rapid, passive adsorption followed by a much slower active bioaccumulation process
Observation under a microscope showed that the S. spinosus cells that were separated from the wastewater grew well in the simulated nuclear wastewater
The grey relational grade analysis showed that the order for different co-existing metal ion effects on strontium ion biosorption was Fe3+ > Cr3+ > Ni2+ > K+ > Cs+

Summary

Introduction

The biosorption of heavy metals by living or growing biomasses involves two processes: an initial rapid, passive adsorption followed by a much slower active bioaccumulation process. The former is a metabolism-independent process, while the latter is metabolism-dependent [1,2]. The investigation of adsorption and bioaccumulation processes and their mechanisms can facilitate application of these techniques in wastewater treatment or other associated fields. It is believed that this discovery can help scientists design suitable methods to bioremove radioactive strontium from existing nuclear wastewater streams as many algae have immense metal ion biosorption capabilities [2]

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Results

Conclusion