Removal of yttrium from rare-earth wastewater by Serratia marcescens: biosorption optimization and mechanisms studies

Abstract

The discharge of yttrium containing wastewater is a potential risk to human health. Although biosorption is a promising method to remove yttrium from wastewater, whereas the application of it is limited due to the lack of efficient biosorbents. In this study, the removal of yttrium from wastewater using Serratia marcescens as a biosorbent was conducted. The effects of six parameters including pH (2–5.5), initial yttrium concentration (10–110 mg/L), biosorbent dosage (0.1–0.5 g/L), biosorption time (10–700 min), stirring speed (50–300 rpm) and temperature (20–60 °C) were evaluated. The main parameters were optimized using response surface methodology. The results showed that the adsorption capacity reached 123.65 mg/g at the optimized conditions. The biosorption mechanism was revealed based on a combined analysis using field emission transmission electron microscope-energy dispersion spectrum, Fourier transform infrared spectrophotometer, and X-ray photoelectron spectroscopy. These results revealed that the hydroxyl, carboxyl, and amino groups were the adsorption functional groups for yttrium ions. Biosorption of yttrium by S. marcescens is under the combination of ion exchange, electrostatic attraction and complexation. These findings indicated that S. marcescens can be used as an efficient biosorbent to remove yttrium from wastewater. In addition, its adsorption capacity can be further improved by the enhancement of adsorption functional groups on the surface through chemical modification.

Rare earths stick to rare cyanobacteria: Future potential for bioremediation and recovery of rare earth elements

“…In addition, metal analysis strongly indicated an ion-exchange mechanism during the biosorption process in which Na + , K + , Mg 2+ , and Ca 2+ ions are replaced by metal cations that bind to the surface of the biomass. These observations are in accordance with previous studies that were conducted on algal, bacterial, and other biomasses (Acheampong et al, 2011;Sulaymon et al, 2013;Liang and Shen 2022). The isolation of single target elements in a technical biosorption process remains a challenging task due to the complex surface structure and the heterogeneity of functional groups.…”

“…At pH 1, no notable metal adsorption was measured for all tested biomasses. These results are in accordance with previous studies on cyanobacteria, bacteria, and green algae regarding metal adsorption (Kuyucak and Volesky 1988;Gong et al, 2005;Lupea et al, 2012;Liang and Shen 2022).…”

“…For the adsorption process of REE, the results in this study indicate an ion-exchange mechanism in which cations of alkaline and alkaline earth metals (Na, K, Mg, and Ca) are replaced by other metal cations during the biosorption process with cyanobacterial biomass (Figure 6). This is in agreement with previous experiments using biomass of different microorganisms (Crist et al, 1994;Matheickal et al, 1997;Sulaymon et al, 2013;Liang and Shen 2022). Ion exchange has been proposed as a dominant mechanism during biosorption (Chen et al, 2002;Iqbal et al, 2009).…”

Physiological Performance and Biosorption Capacity of Exiguobacterium sp. SH31 Isolated from Poly-Extreme Salar de Huasco in the Chilean Altiplano: A Study on Rare-Earth Element Tolerance

“…To date, no studies have reported on the biosorption capacity of the SH31 strain for rare-earth elements. However, a previous report demonstrated that Serratia marcescens can be used to biosorb Y 3+ , suggesting the involvement of hydroxyl, amine, and carboxyl groups derived from proteins and polysaccharides in metal biosorption [38]. Furthermore, the FTIR spectra of a thermophilic bacterium, Thermus scotoductus SA-01, during the biosorption of Eu 3+ , indicated that the interaction occurs mainly through phosphate, carboxyl, and carbonyl of amide groups [8].…”

Bacterial Metal Accumulation as a Strategy for Waste Recycling Management

“…The pH of a solution is one of the most crucial aspects of biosorption since it affects the charge and ionization of functional groups on the cell surface [22]. In general, a low pH seems to be favourable for cation binding stability due to the overall negative charge of the cell surface and increased metal solubility under acidic conditions [27,28], but depending on the metal of interest and the biosorbing organism, binding capacity might decrease under highly acidic solution pH [29]. Other factors, which could increase biosorption include elevated temperatures (increases surface activity and kinetic energy), low ionic strength (less competition of binding sites), high agitation speed (enhances pollutant removal rate by minimizing mass transfer resistance), high pollutant load, etc.…”