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Aegle marmelos leaf extract based synthesis of nanoiron and nanoiron+Au particles for degradation of methylene blue

Tarangini Korumilli, Jagajjanani Rao K., Wacławek Stanisław, Černík Miroslav, Padil Vinod V. T.

Ecological Chemistry and Engineering. S

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2022

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Vol. 29, nr 1

7--14

EN

In this study, nanoiron and nanoiron+Au particles were synthesised using aqueous Aegle marmelos extract using a facile and one-pot approach. Lower size non-magnetic nanoiron (~34 nm) and nanoiron (~34 nm)+Au particles (1 to 1.5 μm) were produced from the same medium individually. Nanoparticles suspension behaviour and structural characterisations were carried out by UV-Vis spectroscopy, electron microscopy and by X-ray diffraction techniques. Primarily, for synthesis, a simple bioreduction approach generated amorphous nanoiron particles, which on annealing produced magnetic maghemite, γ-Fe2O3 type nanoparticles with sizes 100 to 1000 nm. Posteriorly, the bioreduction process also produces nanoiron+Au particles and can be used for multifunctional applications. As a model application, catalytic application of the as-prepared nanoiron and nanoiron+Au particles towards methylene blue, a thiazine dye degradation is investigated and found to be effective within 20 min. Langmuir-Hinshelwood kinetic model was exploited to know the degradation behaviour, and the model was found to be fit based on R2 values with the observed experimental data. We suggest that the formed highly stable nanoiron particles with in situ stabilisation offer benefits like consistency, environmental friendliness and suits well for large-scale applicability.

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Utility of Chromobacterium violaceum SUK1a, an indigenous bacterial isolate for the bioremediation of Cr(VI)

Prabhakaran D. C., Krishnan S., Ramamurthy P. C., Sivry Y., Quantin C., Subramanian S.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 4

1266--1281

EN

The potential of an indigenous bacterial strain, Chromobacterium violaceum SUK1a, isolated from surface water samples collected from Sukinda Valley in Odisha, India, has been evaluated for the first time for the bioremediation of toxic hexavalent chromium (Cr(VI)) ions. The isolate was assessed for its Cr(VI) biosorption efficiency and the various parameters affecting the biosorption process were evaluated. A maximum Cr(VI) biosorption of about 50% was obtained, and the residual chromium was in the form of less toxic Cr(III). The Gibbs free energy of biosorption was determined to be -26.3 kJ/mol, suggestive of a chemisorption process. Additionally, the Cr(VI) biosorption by the isolate followed pseudo second order kinetics. FTIR spectral studies indicated that the surface functional groups present on the bacterial isolate such as, carboxyl, hydroxyl, amino, and phosphate groups were involved in the complexation of chromium ions with the bacterial cells. X-ray photoelectron spectroscopic studies on Cr(VI) interacted bacterial cells revealed an additional peak corresponding to Cr(III) in the Cr(2p) spectra. The surface charge of the bacterial cells subsequent to interaction with Cr(VI) were less negative compared to the pristine cells, which further substantiated the bioreduction of Cr(VI) to Cr(III). The bioremediation mechanism of Cr(VI) by the bacterial isolate is delineated to be governed by both biosorption and bioreduction processes under metabolism independent conditions. The results obtained indicate that the isolate can be a promising candidate for Cr(VI) bioremediation applications.

3

Fungal Cells Permeabilization as a Convenient Tool of Bioreduction Enantioselectivity Control

Brzezińska-Rodak M., Żymańczyk-Duda E., Klimek-Ochab M., Lejczak B.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 12

2113-2118

EN

The application of nonionic detergents: Triton X100 and Tween 80, as permeabilizing agents was an effective tool allowing to control the asymmetric hydrogen transfer in the biocatalyzed, enantioselective reduction of acetophenone to the desired optical isomer of 1-phenylethanol. Depending on the permeabilization procedure, the application of Geotrichum candidum, after the Triton X100 was applied, resulted in the formation of the R-enantiomer (79 percent of chemical yield and 72 percent of e.e), whereas bioreduction following the use of Tween 80 led to the S-form of 1-phenylethanol (51 percent of yield and 93 percent of e.e).

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Biocatalytical Synthesis and Further Determination of the Absolute Configuration of Diethyl of (R)-2-Hydroxybutylphosphonate

Brzezińska-Rodak M., Żymańczyk-Duda E., Klimek-Ochab M., Lejczak B.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 11

1911-1916

EN

Biotransformations of diethyl ester of 2-oxobutylphosphonate catalyzed by different kinds of yeasts: Rhodotorula gracilis and baker yeasts al lowed to obtain optically pure product – hydroxyphosphonate of R – absolute configuration. Chemical yield of the reaction was depended on the microbial cells pretreat ment and on the chemical additives, which are known to modify dehydrogenase activity [1].

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Integrated process of ionic mercury bioreduction and adsorption from wastewater

Głuszcz P.

Chemical and Process Engineering

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2007

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Vol. 28, z. 4

909-920

EN

A novel and environmentally friendly technology for removal of ionic mercury from industrial wastewaters is bioremediation. The basic principle of this process is enzymatic reduction of highly toxic Hg(II) to water-insoluble and relatively non-toxic Hg(0) by live mercury resistant bacteria. The goal of presented study was integration of this technology by combining the adsorption and bioreduction steps in one bioreactor using activated carbon as a carrier for microorganisms immobilization and - simultaneously - as an adsorbent for different forms of mercury.

PL

Nowatorską, przyjazną dla środowiska technologią usuwania rtęci jonowej ze ścieków jest bioremediacja, polegająca na enzymatycznej redukcji przez odpowiednio dobrane bakterie toksycznej formy Hg(II) do rtęci metalicznej Hg(0), praktycznie nierozpuszczalnej w roztworach wodnych i dlatego nietoksycznej. Celem przedstawionych badań była integracja bioredukcji z procesem adsorpcji rtęci przez zastosowanie węgla aktywnego do immobilizacji mikroorganizmów i jednoczesnej adsorpcji różnych form rtęci, prowadząca do większej efektywności technologii.