Selenium contaminated waters: An overview of analytical methods, treatment options and recent advances in sorption methods

Santos, Sílvia C.R.; Ungureanu, Gabriela; Boaventura, Rui A.R.; Botelho, Cidália M.S.

doi:10.1016/j.scitotenv.2015.03.107

Cited by 256 publications

(221 citation statements)

References 150 publications

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“…Se is typically found on the earth's crust, rocks, and sedimentary soils [2]. Recent reports state that a significant amount of Se emissions into the atmosphere and aquatic environment is related to industrial and mining activities in addition to agricultural drainage run-off [3–5]. …”

Section: Introductionmentioning

confidence: 99%

Enhanced Adsorption of Selenium Ions from Aqueous Solution Using Iron Oxide Impregnated Carbon Nanotubes

Bakather

Fard

Ihsanullah

et al. 2017

Bioinorganic Chemistry and Applications

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The aim of this research was to investigate the potential of raw and iron oxide impregnated carbon nanotubes (CNTs) as adsorbents for the removal of selenium (Se) ions from wastewater. The original and modified CNTs with different loadings of Fe2O3 nanoparticles were characterized using high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffractometer (XRD), Brunauer, Emmett, and Teller (BET) surface area analyzer, thermogravimetric analysis (TGA), zeta potential, and energy dispersive X-ray spectroscopy (EDS). The adsorption parameters of the selenium ions from water using raw CNTs and iron oxide impregnated carbon nanotubes (CNT-Fe2O3) were optimized. Total removal of 1 ppm Se ions from water was achieved when 25 mg of CNTs impregnated with 20 wt.% of iron oxide nanoparticles is used. Freundlich and Langmuir isotherm models were used to study the nature of the adsorption process. Pseudo-first and pseudo-second-order models were employed to study the kinetics of selenium ions adsorption onto the surface of iron oxide impregnated CNTs. Maximum adsorption capacity of the Fe2O3 impregnated CNTs, predicted by Langmuir isotherm model, was found to be 111 mg/g. This new finding might revolutionize the adsorption treatment process and application by introducing a new type of nanoadsorbent that has super adsorption capacity towards Se ions.

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Section: Introductionmentioning

confidence: 99%

Enhanced Adsorption of Selenium Ions from Aqueous Solution Using Iron Oxide Impregnated Carbon Nanotubes

Bakather

Fard

Ihsanullah

et al. 2017

Bioinorganic Chemistry and Applications

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“…As more stringent regulations come into force in order to limit the discharge of Se-containing waste, the use of bioremediation technologies are preferable because they will offer more cost-effective approaches for the removal of the pollutant. There has been a growing interest in the use of microorganisms in remediating Secontaminated environments (96)(97)(98)(99). In this context, a number of studies have been carried out in order to exploit the use of Seoxyanion-reducing microorganisms in small/large-scale remediation schemes.…”

Section: Selenium Bioremediationmentioning

confidence: 99%

Microbial Transformations of Selenium Species of Relevance to Bioremediation

Eswayah

Smith

Gardiner

2016

Appl Environ Microbiol

167

102

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b Selenium species, particularly the oxyanions selenite (SeO 3 2؊ ) and selenate (SeO 4 2؊ ), are significant pollutants in the environment that leach from rocks and are released by anthropogenic activities. Selenium is also an essential micronutrient for organisms across the tree of life, including microorganisms and human beings, particularly because of its presence in the 21st genetically encoded amino acid, selenocysteine. Environmental microorganisms are known to be capable of a range of transformations of selenium species, including reduction, methylation, oxidation, and demethylation. Assimilatory reduction of selenium species is necessary for the synthesis of selenoproteins. Dissimilatory reduction of selenate is known to support the anaerobic respiration of a number of microorganisms, and the dissimilatory reduction of soluble selenate and selenite to nanoparticulate elemental selenium greatly reduces the toxicity and bioavailability of selenium and has a major role in bioremediation and potentially in the production of selenium nanospheres for technological applications. Also, microbial methylation after reduction of Se oxyanions is another potentially effective detoxification process if limitations with low reaction rates and capture of the volatile methylated selenium species can be overcome. This review discusses microbial transformations of different forms of Se in an environmental context, with special emphasis on bioremediation of Se pollution. Since the discovery in 1954 by Pinsent that the oxidation of formate by cell suspensions of Escherichia coli requires growth medium containing molybdate and selenite, there has been a growing interest in the biochemical role of selenium in microorganisms (1). Se is an essential component of selenoamino acids, such as selenomethionine and selenocysteine (the 21st proteinogenic amino acid), that occur in certain types of prokaryotic enzymes. Indeed, the requirement for selenite in E. coli growing on formate is linked to the fact that formate dehydrogenase contains selenocysteine. Other prokaryotic enzymes that contain selenocysteine include glycine reductase in several clostridia, formate dehydrogenases in diverse prokaryotes, including Salmonella, Clostridium, and Methanococcus, as well as hydrogenases in Methanococcus and other anaerobes. In addition, other bacterial Se-dependent enzymes, in which the selenium is part of the active site molybdenum-containing cofactor, include nicotinic acid dehydrogenase and xanthine dehydrogenase, which is present in certain clostridial species (2-4).Reactions that are involved in the cycling of Se in soil, including those influenced by microbes, are diagrammatically summarized in Fig. 1 2Ϫ and was spatially separated from sulfate reduction in the environment despite the presence of substantial concentrations of sulfate where it occurred. Thus, it can be concluded that Se and S have different reductive biogeochemical cycles and appear to involve distinct populations of microorganisms.With respect to the remediation of sel...

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“…Se VI was tested as redox-sensitive species to be reductively precipitated by Fe 0 . This effort was supported by an impressive number of modern analytical tools, using both bulk and surface methods [15,109,110,114,115]. Related studies tested several types of ) like in the Harza Process and (ii) characterizing the intrinsic reactivity of individual materials [38].…”

Section: Lessons From the Fe 0 /Se Systemmentioning

confidence: 99%

Rescuing Fe0 remediation research from its systemic flaws

Noubactep¹,

Makota²,

Bandyopadhyay³

2017

Res Rev Insights

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The well-accepted assumption of metallic iron (Fe 0 ) acting as electron donor for environmental remediation has created an unstable domain of knowledge for the past 23 years. This assumption is discouraging some outstanding and prospective scientists from correctly interpreting their experimental results. Such a situation is a recipe for long-term decline. The critical situation cannot be solved with simplistic approaches. It is now imperative to develop an understanding to defend the difficulties of this assumption and re-orient Fe 0 mediated remediation research as a whole.

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Selenium contaminated waters: An overview of analytical methods, treatment options and recent advances in sorption methods

Cited by 256 publications

References 150 publications

Enhanced Adsorption of Selenium Ions from Aqueous Solution Using Iron Oxide Impregnated Carbon Nanotubes

Enhanced Adsorption of Selenium Ions from Aqueous Solution Using Iron Oxide Impregnated Carbon Nanotubes

Microbial Transformations of Selenium Species of Relevance to Bioremediation

Rescuing Fe0 remediation research from its systemic flaws

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