Search results

1

Activated carbons for the removal of heavy metal ions: A systematic review of recent literature focused on lead and arsenic ions

100%

Deliyanni E. A., Kyzas G. Z., Triantafyllidis K. S., Matis K. A.

Open Chemistry

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2015

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vol. 13

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issue 1

EN

This work is a systematic review of the literature over the past decade of the application of activated carbon (microporous or mesoporous) as adsorbents for the removal of heavy metals, focusing especially on lead (Pb) and arsenic (As) ions from the aqueous phase. Classical examples from our lab are also given. Activated carbon is known to provide a high surface area for adsorption. Generally, surface modification is typically required, such as oxidation, treatment with ammonia or even impregnation with ferric ion, etc. and the adsorbent material may originate from various sources. The pristine materials, after modification and those after batch-wise adsorption, were characterized by available techniques (BET analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, thermal analyses, X-ray photoelectron spectroscopy). Adsorption isotherms, thermodynamics and kinetics of the process are also discussed. Selected studies from the literature are examined in comparison with other adsorbents. The role of chemistry in the metals adsorption/removal was investigated.

2

Application of fly ash agglomerates in the sorption of arsenic

100%

Polowczyk I., Bastrzyk A., Koźlecki T., Rudnicki P., Sawiński W., Sadowski Z., Sokołowski A.

Polish Journal of Chemical Technology

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2007

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vol. 9

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issue 2

37-41

EN

The scope of this contribution was to investigate in detail an application of fly ash adsorbent for the removal of arsenite ions from à dilute solution. The experiments have been carried out using fly ash from black coal burning power plant "Siersza" and brown coal burning power plant "Turów" (Poland), which was wetted, then mixed and tumbled in the granulator with a small amount of cement to increase the mechanical strength of agglomerates. The measurements of arsenic adsorption from the aqueous solution were carried out in the flask (with shaking), as well as in the column (with circulation), in order to compare two different methods of contacting waste with adsorbent. The adsorption isotherms of arsenic were determined for granulated material, using the Freundlich model. Kinetics studies indicated that the sorption follows a pseudo-first-order (PFO) model (Lagergren) and the Elovich-type model.

3

Non-chromatographic methods focused on speciation of arsenic and selenium in food and environmental samples

100%

Rezende H. C., Almeida I. L. S., Coelho L. M., Coelho N. M. M., Marques T. L.

Sample Preparation

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2014

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vol. 2

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issue 1

EN

Speciation is a promising and essential tool in the evaluation of the contamination of metals in food and environmental samples. In this context, information about the species of these elements is important considering that toxic effects are directly related to their chemical forms. The enormous progress in combining separation and detection techniques has enabled the effective chemical speciation. However, a possible source of error in studies of speciation occurs during sample preparation. Appropriate treatment of samples is necessary in order to ensure that interconversion between the species does not occur during the experimental procedure prior to the final analysis. In this review, methods of sample preparation for the determination of arsenic and selenium in food and environmental samples are discussed. We decided to focus on these elements since they account for around 50% of all speciation studies. Procedures including conventional extraction, microwave-assisted extraction and sonolysis are discussed as simple ways to ensure species selectivity. The main purpose of this review is to provide an update on the recent literature concerning the strategies for arsenic and selenium speciation and to critically discuss their advantages and weaknesses compared with the commonly accepted approach of combining non-chromatographic and spectroscopic techniques. The problems focused on involve sampling, sample preparation and storage, as well as changes in ‘species information’ that occur during the use of various separation technologies. These difficulties are described along with recent developments aimed at overcoming these potential issues.

4

Arsenic in Agricultural Soils of Slovakia

88%

Kobza J.

Polish Journal of Soil Science

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2021

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vol. 54

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issue 1

EN

The article presents the current distribution of arsenic in agricultural soils of Slovakia. The current concentration of arsenic (extracted with aqua regia) was measured and evaluated based on 318 monitoring sites of national soil monitoring system in Slovakia. Based on the obtained results, one can state that the average content of arsenic is lower than the valid hygienic limit for arsenic (25 mg.kg-1) for predominated sandy-loamy and loamy soils in Slovakia. Increased values of arsenic were determined only for the Horná – Upper Nitra region (anthropogenic impact) – 24.5 mg.kg-1 and for the Stredný – Central Spiš region (mixed anthrophogenic and geogenic impact) – 129.5 mg.kg-1. These regions belong to the most arsenic-affected regions in Slovakia, where the content of bioavailable forms of arsenic is also increased in the range of 0.013–0.997 mg.kg-1. The hygienic limit for bioavailable arsenic in soils of Slovakia is 0.4 mg.kg-1. Finally, there is a serious risk of arsenic transport from soil into the plants and food chain especially in case of acid soils. A higher risk of As presence seems to be in anthropogenically affected soils.

5

Selenite restores Pax6 expression in neuronal cells of chronically arsenic-exposed Golden Syrian hamsters

88%

Aguirre-Vázquez A., Sampayo-Reyes A., González-Escalante L., Hernández A., Marcos R., Castorena-Torres F., Lozano-Garza G., Taméz-Guerra R., Bermúdez de León M.

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2017

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vol. 64

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issue 4

635-639

EN

Arsenic is a worldwide environmental pollutant that generates public health concerns. Various types of cancers and other diseases, including neurological disorders, have been associated with human consumption of arsenic in drinking water. At the molecular level, arsenic and its metabolites have the capacity to provoke genome instability, causing altered expression of genes. One such target of arsenic is the Pax6 gene that encodes a transcription factor in neuronal cells. The aim of this study was to evaluate the effect of two antioxidants, α-tocopheryl succinate (α-TOS) and sodium selenite, on Pax6 gene expression levels in the forebrain and cerebellum of Golden Syrian hamsters chronically exposed to arsenic in drinking water. Animals were divided into six groups. Using quantitative real-time reverse transcriptase (RT)-PCR analysis, we confirmed that arsenic downregulates Pax6 expression in nervous tissues by 53 ± 21% and 32 ± 7% in the forebrain and cerebellum, respectively. In the presence of arsenic, treatment with α-TOS did not modify Pax6 expression in nervous tissues; however, sodium selenite completely restored Pax6 expression in the arsenic-exposed hamster forebrain, but not the cerebellum. Although our results suggest the use of selenite to restore the expression of a neuronal gene in arsenic-exposed animals, its use and efficacy in the human population require further studies.

6

Behavior of arsenic in hydrometallurgical zinc production and environmental impact

88%

Peltekov A. B., Boyanov B. S., Markova T. S.

Polish Journal of Chemical Technology

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2014

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vol. 16

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issue 4

80-86

EN

The presence of arsenic in zinc sulphide concentrates is particularly harmful, because it creates problems in zinc electrolysis. The main source of arsenic in non-ferrous metallurgy is arsenopyrite (FeAsS). In oxidative roasting of zinc concentrates, FeAsS oxidizes to arsenic oxides (As2O3, As2O5). In this connection a natural FeAsS was examined, and also the distribution of arsenic in the products of the roasting process, the cycle of sulphuric acid obtaining and the leaching of zinc calcine were studied. The arsenic contamination of soils in the vicinity of nonferrous metals smelter KCM SA, Plovdiv, Bulgaria as a result of zinc and lead productions has been studied.

7

Use of fly ash and fly ash agglomerates for As(III) adsorption from aqueous solution

88%

Ulatowska J., Polowczyk I., Sawiński W., Bastrzyk A., Koźlecki T., Sadowski Z.

Polish Journal of Chemical Technology

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2014

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vol. 16

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issue 1

21-27

EN

The objective of the present study is to assess the efficiency of fly ash and fly ash agglomerates to remove arsenic(III) from aqueous solution. The maximum static uptakes were achieved to be 13.5 and 5.7 mgAs(III)/adsorbent for nonagglomerated material and agglomerated one, respectively. Isotherm studies showed good fit with the Langmuir (fly ash) and the Freundlich (fly ash agglomerates) isotherm models. Kinetic studies indicated that the sorption of arsenic on fly ash and its agglomerates follows the pseudo-second-order (PSO) chemisorption model (R2 = 0.999). Thermodynamic parameters revealed an endothermic nature of As(III) adsorption on such adsorbents. The adsorption results confirmed that fly ash and its agglomerates can be used for As(III) removal from aqueous solutions. Fly ash can adsorb more arsenic(III) than agglomerates, which are easier to use, because this material is less dusty and easier to separate from solution.

8

Determination of inorganic arsenic species As(III) and As(V) by high performance liquid chromatography with hydride generation atomic absorption spectrometry detection

88%

Niedzielski P., Siepak M., Novotny K.

Open Chemistry

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2004

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vol. 2

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issue 1

82-90

EN

The paper presents the principles and advantages of a technique combining high performance liquid chromatography and hydride generation atomic absorption spectrometry (HPLC-HGAAS) applied to speciation analysis of inorganic species of arsenic As(III) and As(V) in ground water samples. With separation of the arsenic species on an ion-exchange column in the chromatographic system and their detection by the hydride generation atomic absorption spectrometry, the separation of the analytical signals of the arsenic species was excellent at the limits of determination of 1.5 ng/ml As(III) and 2.2 ng/ml As(V) and RSD of 4.3% and 7.8% for the concentration of 25 ng/ml. The hyphenated technique has been applied for determination of arsenic in polluted ground water in the course of the study on migration of micropollutants. For total arsenic concentration two independent methods: HGICP-OES and HGAAS were used for comparison of results of real samples analysis.

9

Arsenic Immobilization by Nanoscale Zero-Valent Iron / Immobilizacja Arsenu Przez Nanożelazo Na Zerowym Stopniu Utlenienia

63%

Rodová A., Filip J., Černík M.

Ecological Chemistry and Engineering S

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2015

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vol. 22

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issue 1

45-59

EN

Contaminated mine water from the Kank site (Czech Republic) containing arsenic at a concentration of approximately 85 mg/dm3 was tested in a reaction with elemental iron nanoparticles. In a reductive environment there was a reduction of As to the more soluble and toxic form of As(III) depending on the pH of the solution. Oxidation of elemental iron creates oxyhydroxides which incorporate As into their structure in the form of mixed complexes and thereby remove and bind dissolved As from the solution. The addition of 0.5 g/dm3 nZVI to the contaminated water leads to a significant decrease in ORP and concentrations of As to around the detection limit. The pH of the solution is not significantly affected by the addition of nZVI. The main competing anion for co-precipitation is represented by phosphates whose concentration after the addition of nZVI was reduced to 6.5% of the original value. The resulting precipitates were analyzed by XPS, XRF, XRD, SEM-EDX and Mössbauer spectroscopy. The presence of jarosite, Schwertmannite and also arsenic probably in the form of skorodite was confirmed

PL

W Kaňk (Czeska Republika) znajduje się zanieczyszczona woda z kopalni, zawierająca arsen o przybliżonym stężeniu 85 mg/dm3. Została ona poddana reakcji z nanocząteczkami żelaza na zerowym stopniu utlenienia (nZVI). W zależności od pH roztworu w środowisku redukcyjnym przebiegła reakcja redukcji As do bardziej rozpuszczalnej i toksycznej formy As(III). Poprzez utlenienie elementarnego żelaza powstają tlenowodorotlenki, łączące się z As w postać kompleksów mieszanych, tym samym usuwając As z zanieczyszczonego roztworu. Dodatek 0,5 g/dm3 nZVI do zanieczyszczonej wody prowadzi do znaczącego spadku wartości ORP i obniżenia stężenia As do granic wykrywalności. Dodatek nZVI nie ma znaczącego wpływu na wartość pH roztworu. Głównym anionem konkurującym we współstrąceniu As jest anion fosforanowy, którego stężenie po dodaniu nZVI zmniejszyło się do 6,5% w porównaniu do wartości wyjściowej. Powstały osad został poddany analizie metodami: XPS XRF, XRD, SEM-EDX i spektroskopią Mössbauerowską. Została potwierdzona obecność jarosytu, schwertmannitu oraz arsenu prawdopodobnie w postaci skorodytu

10

Removal of arsenic compounds with peat, peat-based and synthetic sorbents / Usuwania związków arsenu za pomocą torfu, sorbentów na bazie torfu i sorbentów syntetycznych

63%

Ansone L., Eglite L., Klavins M.

Ecological Chemistry and Engineering S

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2012

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vol. 19

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issue 4

513-531

EN

Arsenic contamination of waters is a global problem; therefore, new approaches for its removal are needed. Peat, peat modified with iron compounds, iron humates and polymeric cation exchangers modified with iron were prepared and tested for sorption of arsenic compounds in comparison with weakly basic anionites. The highest sorption capacity was observed when peat sorbents modified with iron compounds were used. Sorption of different arsenic speciation forms onto iron-modified peat sorbents was investigated as a function of pH and temperature. It was established that sorption capacity increases with a rise in temperature, and the calculation of sorption process thermodynamic parameters indicates the spontaneity of sorption process and its endothermic nature.

PL

Skażenie wód arsenem jest problemem globalnym, dlatego potrzebne są nowe sposoby jego usuwania. Zbadano sorpcję związków arsenu przez torf, torf modyfikowany związkami żelaza, sole żelaza i kwasów humusowych oraz polimerowe kationity modyfikowane żelazem. Wyniki porównano z sorpcją związków arsenu przez anionity słabo zasadowe. Najwyższą wydajność sorpcji zaobserwowano dla torfowych sorbentów modyfikowanych związkami żelaza. Badano sorpcję różnych form specjacyjnych arsenu na sorbentach na bazie torfu modyfikowanych żelazem, w zależności od pH i temperatury. Stwierdzono wzrost pojemności sorpcyjnych tego materiału wraz ze wzrostem temperatury. Obliczone parametry termodynamiczne procesu sorpcji wskazują na samorzutność tego procesu i jego endotermiczność.

11

Arsenic removal through bio sand filter using different bio-adsorbents

63%

Keerio G. S., Keerio H. A., Ibuphoto K. A., Laghari M., Panhwar S., Talpur M. A., Keerio G. S., Keerio H. A., Ibuphoto K. A., Laghari M., Panhwar S., Talpur M. A.

Journal of Water and Land Development

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2021

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issue 48

12

Extraction of vanadium and potassium compounds from the spent vanadium catalyst from the metallurgical plant

51%

Mazurek K.

Polish Journal of Chemical Technology

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2012

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vol. 14

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issue 2

49-53

EN

A spent vanadium catalyst, from the plant of metallurgical type, was leached in a sulfuric acid solution to recover vanadium and potassium compounds. The effect of time, temperature, concentration of acid, catalyst particle size and phase ratio was studied. Additionally the concentration of iron, copper, zinc, arsenic and lead compounds was determined. The flow sheet for the proposed process of spent vanadium catalyst leaching is presented.

Refine search results

Activated carbons for the removal of heavy metal ions: A systematic review of recent literature focused on lead and arsenic ions

Application of fly ash agglomerates in the sorption of arsenic

Non-chromatographic methods focused on speciation of arsenic and selenium in food and environmental samples

Arsenic in Agricultural Soils of Slovakia

Selenite restores Pax6 expression in neuronal cells of chronically arsenic-exposed Golden Syrian hamsters

Behavior of arsenic in hydrometallurgical zinc production and environmental impact

Use of fly ash and fly ash agglomerates for As(III) adsorption from aqueous solution

Determination of inorganic arsenic species As(III) and As(V) by high performance liquid chromatography with hydride generation atomic absorption spectrometry detection

Arsenic Immobilization by Nanoscale Zero-Valent Iron / Immobilizacja Arsenu Przez Nanożelazo Na Zerowym Stopniu Utlenienia

Removal of arsenic compounds with peat, peat-based and synthetic sorbents / Usuwania związków arsenu za pomocą torfu, sorbentów na bazie torfu i sorbentów syntetycznych

Arsenic removal through bio sand filter using different bio-adsorbents

Extraction of vanadium and potassium compounds from the spent vanadium catalyst from the metallurgical plant