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Rafal Sitko

Other affiliations: Silesian University
Bio: Rafal Sitko is an academic researcher from University of Silesia in Katowice. The author has contributed to research in topics: Fluorescence spectrometry & Adsorption. The author has an hindex of 28, co-authored 107 publications receiving 3064 citations. Previous affiliations of Rafal Sitko include Silesian University.


Papers
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TL;DR: Potential application of GO in analytical chemistry as a solid sorbent for preconcentration of trace elements and in heavy metal ion pollution cleanup results from its maximum adsorption capacities that are much higher than those of any of the currently reported sorbents.
Abstract: The adsorptive properties of graphene oxide (GO) towards divalent metal ions (copper, zinc, cadmium and lead) were investigated GO prepared through the oxidation of graphite using potassium dichromate was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FT-IR) The results of batch experiments and measurements by flame atomic absorption spectrometry (F-AAS) indicate that maximum adsorption can be achieved in broad pH ranges: 3–7 for Cu(II), 5–8 for Zn(II), 4–8 for Cd(II), 3–7 for Pb(II) The maximum adsorption capacities of Cu(II), Zn(II), Cd(II) and Pb(II) on GO at pH = 5 are 294, 345, 530, 1119 mg g−1, respectively The competitive adsorption experiments showed the affinity in the order of Pb(II) > Cu(II) ≫ Cd(II) > Zn(II) Adsorption isotherms and kinetic studies suggest that sorption of metal ions on GO nanosheets is monolayer coverage and adsorption is controlled by chemical adsorption involving the strong surface complexation of metal ions with the oxygen-containing groups on the surface of GO Chemisorption was confirmed by XPS (binding energy and shape of O1s and C1s peaks) of GO with adsorbed metal ions The adsorption experiments show that the dispersibility of GO in water changes remarkably after complexation of metal ions After adsorption, the tendency to agglomerate and precipitate is observed Excellent dispersibility of GO and strong tendency of GO–Me(II) to precipitate open the path to removal of heavy metals from water solution Potential application of GO in analytical chemistry as a solid sorbent for preconcentration of trace elements and in heavy metal ion pollution cleanup results from its maximum adsorption capacities that are much higher than those of any of the currently reported sorbents

690 citations

Journal ArticleDOI
TL;DR: In this paper, the adsorptive properties of G and GO and their application in preconcentrating organic compounds and trace-metal ions, including trace analysis of water, food, biological and environmental samples using chromatography and spectroscopy techniques are discussed.
Abstract: In the past three years, we have seen intense interest grow in graphene (G) and graphene oxide (GO) as new sorbents in analytical chemistry. This article focuses on the adsorptive properties of G and GO and their application in preconcentrating organic compounds and trace-metal ions, including trace analysis of water, food, biological and environmental samples using chromatography and spectroscopy techniques. Some methods of modification or chemical functionalization of G and GO are also discussed. The article shows that G, GO and their derivatives or composites can be very attractive as sorbents due to their adsorption capacities being much higher than those of any of the currently reported sorbents.

330 citations

Journal ArticleDOI
TL;DR: GO-SH can be applied to the arsenic speciation due to its selectivity toward arsenite and is suitable for the analysis of water, including high salinity samples difficult to analyze using other spectroscopy techniques.
Abstract: A new method based on dispersive microsolid phase extraction (DMSPE) and total-reflection X-ray fluorescence spectrometry (TXRF) is proposed for multielemental ultratrace determination of heavy metal ions and arsenic species. In the developed methodology, the crucial issue is a novel adsorbent synthesized by grafting 3-mercaptopropyl trimethoxysilane on a graphene oxide (GO) surface. Mercapto-modified graphene oxide (GO-SH) can be applied in quantitative adsorption of cobalt, nickel, copper, cadmium, and lead ions. Moreover, GO-SH demonstrates selectivity toward arsenite in the presence of arsenate. Due to such features of GO-SH nanosheets as wrinkled structure and excellent dispersibility in water, GO-SH seems to be ideal for fast and simple preconcentration and determination of heavy metal ions using methodology based on DMSPE and TXRF measurement. The suspension of GO-SH was injected into an analyzed water sample; after filtration, the GO-SH nanosheets with adsorbed metal ions were redispersed in a sma...

169 citations

Journal ArticleDOI
TL;DR: An overview of publications focussed on the period since 2000 and outlining modern methods of sample preparation as well as advanced techniques for determination of rare earth elements (REE) in various matrices is presented in this article.
Abstract: An overview of publications focussed on the period since 2000 and outlining modern methods of sample preparation as well as advanced techniques for determination of rare earth elements (REE) in various matrices is presented in this paper. The review discusses the problems of REE determination in diverse samples i.e. from biological through environmental and geological to advanced materials. The preferable procedure of sample digestion and the most frequently applied methods of sample preparation for determination of trace elements are discussed in this paper. The case of direct analysis of samples for REE determination is also discussed. The review outlines determination of REE employing many techniques such as, inter alia, flame or graphite furnace atomic absorption spectrometry, atomic absorption with chemical vapor generation, X-ray fluorescence spectrometry, inductively coupled plasma optical emission spectrometry, inductively coupled plasma mass spectrometry and neutron activation analysis. This article summarizes and classifies materials in which rare earth elements are present, main places of their occurrence and the methods of their analysis.

156 citations

Journal ArticleDOI
TL;DR: In this paper, the authors discuss functionalization of CNTs through oxidation and further modification via creation of amide or ester bonds, and present CNT-based composites, including magnetic composites.
Abstract: Carbon nanotubes (CNTs) have received much attention for their many potential applications in analytical chemistry due to their adsorptive properties. Unmodified CNTs can be used as sorbents in solid-phase extraction (SPE), especially if metal ions are complexed with an appropriate chelating agent. However, raw CNTs are insoluble and hardly dispersible in solvents due to strong van der Waals interactions that hamper sorption of metal ions. Proper surface treatment of CNTs not only enhances dispersibility but also improves metal sorption and selectivity in SPE. This review focuses on chemical modification of CNTs. We discuss functionalization of CNTs through oxidation and further modification via creation of amide or ester bonds. We also review radical addition with aryl-diazonium salts and the N 2 -plasma technique as effective methods of grafting functional groups onto CNT surfaces. Moreover, we present CNT-based composites, including magnetic composites. We show that modified CNTs and their composites can be very attractive as sorbents due to their high adsorption capacity. The review includes several applications of modified CNTs in preconcentration and determination of trace-metal ions in water, food, environmental and biological samples.

133 citations


Cited by
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Journal ArticleDOI
TL;DR: This critical review assesses the recent developments in the use of graphene-based materials as sorbent or photocatalytic materials for environmental decontamination, as building blocks for next generation water treatment and desalination membranes, and as electrode materials for contaminant monitoring or removal.
Abstract: Graphene-based materials are gaining heightened attention as novel materials for environmental applications The unique physicochemical properties of graphene, notably its exceptionally high surface area, electron mobility, thermal conductivity, and mechanical strength, can lead to novel or improved technologies to address the pressing global environmental challenges This critical review assesses the recent developments in the use of graphene-based materials as sorbent or photocatalytic materials for environmental decontamination, as building blocks for next generation water treatment and desalination membranes, and as electrode materials for contaminant monitoring or removal The most promising areas of research are highlighted, with a discussion of the main challenges that we need to overcome in order to fully realize the exceptional properties of graphene in environmental applications

1,158 citations

Journal ArticleDOI
TL;DR: Recently, carbonaceous nanofillers such as graphene and carbon nanotubes (CNTs) play a promising role due to their better structural, functional properties and broad range of applications in every field as mentioned in this paper.

1,097 citations

Journal ArticleDOI
TL;DR: In this article, various nanomaterials have been reviewed which have been used for water decontamination and a review has been given on adsorption, photocatalytic and antibacterial activity of nanommaterials.

910 citations

Journal ArticleDOI
TL;DR: This work provides a comprehensive review of recent research on various carbon adsorbents in terms of their surface functional groups and the associated removal behaviors and performances to heavy metals in aqueous solutions.

697 citations

Journal ArticleDOI
TL;DR: Potential application of GO in analytical chemistry as a solid sorbent for preconcentration of trace elements and in heavy metal ion pollution cleanup results from its maximum adsorption capacities that are much higher than those of any of the currently reported sorbents.
Abstract: The adsorptive properties of graphene oxide (GO) towards divalent metal ions (copper, zinc, cadmium and lead) were investigated GO prepared through the oxidation of graphite using potassium dichromate was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FT-IR) The results of batch experiments and measurements by flame atomic absorption spectrometry (F-AAS) indicate that maximum adsorption can be achieved in broad pH ranges: 3–7 for Cu(II), 5–8 for Zn(II), 4–8 for Cd(II), 3–7 for Pb(II) The maximum adsorption capacities of Cu(II), Zn(II), Cd(II) and Pb(II) on GO at pH = 5 are 294, 345, 530, 1119 mg g−1, respectively The competitive adsorption experiments showed the affinity in the order of Pb(II) > Cu(II) ≫ Cd(II) > Zn(II) Adsorption isotherms and kinetic studies suggest that sorption of metal ions on GO nanosheets is monolayer coverage and adsorption is controlled by chemical adsorption involving the strong surface complexation of metal ions with the oxygen-containing groups on the surface of GO Chemisorption was confirmed by XPS (binding energy and shape of O1s and C1s peaks) of GO with adsorbed metal ions The adsorption experiments show that the dispersibility of GO in water changes remarkably after complexation of metal ions After adsorption, the tendency to agglomerate and precipitate is observed Excellent dispersibility of GO and strong tendency of GO–Me(II) to precipitate open the path to removal of heavy metals from water solution Potential application of GO in analytical chemistry as a solid sorbent for preconcentration of trace elements and in heavy metal ion pollution cleanup results from its maximum adsorption capacities that are much higher than those of any of the currently reported sorbents

690 citations