Publications by authors named "Ryszard Dobrowolski"

The pristine CMK-3 carbon was ozonized and then chemically modified by the Zr and Fe compounds. The synthesized carbonaceous materials were characterized with physicochemical methods. The obtained carbons had a high specific surface area (ca.

View Article and Find Full Text PDF
Article Synopsis
  • Fluorine is both essential and potentially toxic to humans and animals, necessitating reliable detection methods in animal feed.
  • The study measured fluorine using a fluoride-selective electrode (ISE) and a new high-resolution spectrometry method, facing challenges like chemical interferences and reagent contamination.
  • Results from both methods were consistent, confirming accuracy in measuring fluorine in its fluoride form, with findings indicating that fluoride levels in most samples were below established safety thresholds.
View Article and Find Full Text PDF

Newly synthesized cerium oxide was successfully obtained by the hard templating route. The optimal As(III) and As(V) adsorption onto the studied adsorbent was reached for the initial pH of 4.0 and a contact time of 10 h.

View Article and Find Full Text PDF

Novel CO- and HPO-modified biochars were successfully synthesized from raw honeycomb biomass. They were characterized via several instrumental techniques. The optimal Pt(II) and Pt(IV) adsorption onto the studied biochars was reached for the initial pH of 1.

View Article and Find Full Text PDF

This paper describes a novel electrode material, diclofenac-impregnated mesoporous carbon modified with a cationic surfactant, cetyltrimethylammonium bromide (DF-CMK-3/CTAB), for ultratrace analysis of the arsenic drug roxarsone (ROX). DF-CMK-3 amorphous carbon is a material with a high specific surface area and well-defined, hexagonally ordered, thin mesopores. The functional groups attached to the carbonaceous surface, such as chromene and pyron-like oxygen groups, lactam, and aromatic carbon rings, have the basic character and they can donate electrons.

View Article and Find Full Text PDF

In this paper, a dicyandiamide-impregnated mesoporous carbon (N-CMK-3), electrochemically modified in situ with lead film (Pb-N-CMK-3), was tested as an electrode material for U(VI) ultratrace determination. The prepared carbon material was characterized by XRD, SEM-EDX, Raman, FT-IR, XPS analysis and nitrogen sorption measurements. The changes of electrochemical properties of glassy carbon electrodes (GCE) after the N-CMK-3 and Pb-N-CMK-3 modification were studied using CV and EIS methods.

View Article and Find Full Text PDF

Ordered mesoporous carbon (CMK-3), obtained from an abundant natural source, sugar, was thermochemically modified with dicyandiamide and thiourea as well as by classical oxidization with hydrogen peroxide to introduce specific surface groups. Thermochemical modifications resulted in carbon with almost unchanged porosity and altered surface chemistry while porosity of HO-treated carbon was seriously deteriorated. The obtained carbons were tested as sorbents of diclofenac, considered as one of the emerging water contaminants.

View Article and Find Full Text PDF

The objective of this study was to evaluate the fractionation of ZnO and CuO engineered nanoparticles (ENPs) in soils with a pH adjusted to 4.0, 6.5, and 9.

View Article and Find Full Text PDF

Background: Auranofin, a Food and Drug Administration-approved anti-rheumatic agent with anticancer properties for lung and ovarian cancer, has never been studied for pancreatic cancer. We hypothesize that auranofin may prevent pancreatic ductal adenocarcinoma progression by inhibition of Txnrd1 and HIF-1α.

Methods: sensitivity of human pancreatic ductal adenocarcinoma cell lines was determined based on IC50.

View Article and Find Full Text PDF

A gold(III)-imprinted thiocyanato-functionalized silica network of type SBA-15 was prepared by co-condensation of tetraethoxysilane (TEOS) with thiocyanatopropyltriethoxysilane (TCTES) in the presence of Pluronic123 and Au(III) ions. Compared to the non-imprinted material, the imprint has a higher selectivity and adsorption capacity for Au(III). The maximum static adsorption capacity for Au(III) is 475 mg·g for the ion-imprinted, and 62 mg·g for the non-imprinted sorbent.

View Article and Find Full Text PDF

The goal of the study was to evaluate the application of biochar (BC) to the sewage sludge (SL) on the adsorption and desorption capacity of Cd(II), Cu(II), Ni(II) and Zn(II). The effect of biochar contribution in the sewage sludge (2.5, 5 and 10%) was investigated.

View Article and Find Full Text PDF

The objective of the study was to investigate the ability of biochars prepared under different temperatures (400 °C and 600 °C) from the residue of biogas production (RBP) for the adsorption of cadmium (Cd(II)) and nickel (Ni(II)) ions from aqueous solution. Furthermore, the RBP biochars adsorption capacity was compared with adsorption capacity of biochar produced from wheat straw at 600 °C (BCS600). The kinetics of the adsorption, the sorption isotherms, the influence of solution pH and the interfering ions (chlorides and nitrates) were investigated.

View Article and Find Full Text PDF

The adsorption of Cd(II), Pb(II), Ni(II), Co(II) and Cr(VI) ions on the extracellular polymeric substances (EPS) obtained from bacterial strain Rhodococcus opacus and Rhodococcus rhodochrous was investigated by the static sorption method. Influence of pH, time and temperature were studied. It was found that the influence of the pH value and time of adsorption depends on the type of adsorbed ions.

View Article and Find Full Text PDF

The goal of the presented work was the evaluation and comparison of two biochars (produced from Sida hermaphrodita - BCSH/laboratory produced and from wheatstraw - BCS/commercial available) to adsorb heavy metal ions (Cd(II), Cu(II) and Zn(II)) from water. Kinetics of the sorption as well as sorption isotherms, the influence of solution pH and interfering ions were investigated. Different physico-chemical properties of biochars had the great influence on adsorption capacity.

View Article and Find Full Text PDF

Slurry sampling graphite furnace atomic absorption spectrometry technique was applied for the determination of Bi in environmental samples. The study focused on the effect of Zr, Ti, Nb and W carbides, as permanent modifiers, on the Bi signal. Because of its highest thermal and chemical stability and ability to substantially increase Bi signal, NbC was chosen as the most effective modifier.

View Article and Find Full Text PDF

In the present research, the potential of two biochars produced by the thermal decomposition of wheat straw (BCS) and wicker (BCW) for Cr(VI) ions removing from wastewater was investigated. The pH and the presence of chlorides and nitrates were also investigated. The Freundlich and Langmuir models were applied for the characterization of adsorption isotherms.

View Article and Find Full Text PDF

A new analytical procedure for vanadium (V) determination in soils and sediments by the slurry sampling graphite furnace atomic absorption spectrometry (slurry sampling GFAAS) using the mixed permanent modifiers is described. Moreover, the comparison of action of the modifiers based on the iridium (Ir) and carbide-forming elements: tungsten (W) and niobium (Nb) deposited on the graphite tubes is studied, especially in terms of their analytical utility and determination sensitivity. The mechanism of their action was investigated using an X-ray diffraction technique (XRD) and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray detector (EDX).

View Article and Find Full Text PDF

The adsorbent, based on the thermal modification of activated carbon impregnated by iron(III) nitrate(V), has been prepared and applied for selenium enrichment from aqueous solution. Various ratios of the impregnating agent to carbon mass were carefully examined with respect to selenium adsorption capacity and selectivity. The basic Se(VI) ions adsorption parameters affecting the adsorption ability onto the prepared activated carbons were studied.

View Article and Find Full Text PDF

A simple and cost effective preconcentration method on modified activated carbons is described for the determination of traces of gold (Au) in geological samples by carbon slurry sampling graphite furnace atomic absorption spectrometry (GFAAS). The basic parameters affecting the adsorption capacity of Au(III) ions on modified activated carbons were studied in detail and the effect of activated carbons modification has been determined by studying the initial runs of adsorption isotherms. The influence of chlorides and nitrates on adsorption ability of Au(III) ions onto the modified activated carbons for diluted aqueous solution was also studied in detail in respect to the determination of gold in solid materials after digestion steps in the analytical procedure, which usually involves the application of aqua regia.

View Article and Find Full Text PDF

A simple method, using permanent modifiers, has been developed for chromium (Cr) determination in food of plant origin by the slurry sampling graphite furnace atomic absorption spectrometry. In particular comparison of the action of Mg(NO3)2, iridium (Ir)/niobium (Nb) and iridium (Ir)/tungsten (W) was examined. Finally, for chromium determination in food, the mixture of 2μg of Ir with 10μg of Nb was used as permanent modifier.

View Article and Find Full Text PDF

Introduction: The aim of the study was to determine the content of cadmium (Cd), cobalt (Co) and nickel (Ni) in the samples from laryngeal carcinoma in comparison with the level of these elements in the samples of healthy mucous membrane from the same larynx.

Material And Methods: The study was conducted on 43 patients with laryngeal carcinoma. The levels of Cd, Co, and Ni in carcinoma and healthy control tissues was determined by inductively coupled plasma optical emission spectrometry (ICP - OES) using sequential spectrometer.

View Article and Find Full Text PDF

Slurry sampling atomic absorption spectrometry with electrothermal atomization was used to the determination of cadmium (Cd) and lead (Pb) in soils and sediments using permanent modifiers. Comparison of action of mixed permanent modifiers niobium (Nb)/iridium (Ir) and tungsten (W)/iridium (Ir) were studied in detail. The effect of amount of Ir, W and Nb on analytical signals of Cd and Pb was examined.

View Article and Find Full Text PDF