Search results for "Sorption"

Ethyl hexanoate transfer in paper and plastic food packaging by sorption and permeation experiments

2008

The barrier properties of one treated paper packaging and one standard plastic film (bi-oriented polypropylene, biOPP) were assessed for ethyl hexanoate. Three methods based either on sorption (gravimetry and micro-atmosphere-derived method) or permeation kinetic determination were used in controlled conditions of aroma vapor concentration (107 Pa), temperature (25 degrees C) and relative humidity (about 0 %). Ethyl hexanoate solubility values were on the same range of magnitude for both packaging films in spite of their different nature and composition. Ethyl hexanoate affinity for both films was well predicted by their respective solubility parameters. Solubility values were different acc…

Biological Monitoring Using Lichens as a Source of Information About Contamination of Mountain with Heavy Metals

2022

Abstract The aim of this study was passive biomonitoring of the mountains of southern Poland. Lichens Hypogymnia physodes were used for the study. Concentrations of the heavy metals Ni, Cu, Zn, Cd and Pb were determined in these lichens. The concentrations were measured by atomic absorption spectrometry (AAS). The analysis of the concentrations of the determined heavy metals in the lichen thallus allowed to determine the places with the highest and the lowest contamination with a given heavy metal in the study area. It was shown that the area of Great Czantoria and Big Soszow is the most contaminated with heavy metals among the investigated areas. The study shows that the transport of analy…

Kūdras sastāva ietekme uz elementu akumulāciju zemajos purvos

2016

Elektroniskā versija nesatur pielikumus

Heterogeneous photocatalytic degradation of pharmaceuticals in water by using polycrystalline TiO2 and a nanofiltration membrane reactor

2006

Abstract A study of the photodegradation of different pharmaceuticals [furosemide, ranitidine (hydrochloride), ofloxacine, phenazone, naproxen, carbamazepine and clofibric acid] in aqueous medium at various pHs by using a batch photoreactor and a photocatalytic membrane reactor working in recirculation regime was carried out. Polycrystalline TiO 2 was used as the photocatalyst, and different membranes (NTR 7410, PAN GKSS HV3/T, N 30 F, NF PES 10) were tested. A different adsorption of the substrates onto the catalyst surface was observed owing to the hydrophilic/hydrophobic character of the catalyst, depending on the pH. The photodegradation of the seven molecules in the batch reactor was s…

Plasma polymer films and gold nanoparticles: coupling of properties to design a biosensor

The present investigation deals with the functionalization of gold nanoparticles (Au NPs) with primary amine-based plasma polymer films (NH2-PPF), to improve their properties for bioanalytical applications. Cyclopropylamine (CPA) plasma polymerization, in pulsed and continuous wave radio frequency discharges, was employed to growth CPA amino-based PPFs coatings (18 nm) onto Au NPs of 12 nm of diameter deposited on glass and silicon substrates. A multi-technique investigation, based on FT-IR and XPS spectroscopies, AFM and SEM microscopies and Tof-SIMS spectrometry, revealed peculiar features of the CPA PPFs. In particular, by FT-IR it was possible to obtain an overview about the rich chemis…

Metallocenes and post-metallocenes immobilized on ionic liquid-modified silica as catalysts for polymerization of ethylene

2014

Abstract The supported ionic liquid (SIL) strategy was used for the first time to metallocene and post-metallocene heterogeneous catalysts for olefin polymerization. The metal complexes: Cp2TiCl2, Cp2ZrCl2, FI–Ti, and Sal–Ti were immobilized in the 1-(3-triethoxysilyl)propyl-3-methylimidazolium alkylchloroaluminate ionic liquid, anchored on the surface of the mesoporous amorphous silica. The SIL systems were characterized by FTIR, 29Si NMR, N2 adsorption, EA, AAS, TG, and SEM techniques. The developed supported catalytic systems were found to be active in the ethylene polymerization and produce the polyethylene of various properties.

Weathering of low-density polyethylene grafted with itaconic acid in laboratory tests

2011

Polyethylene grafted with itaconic acid was subjected to weathering under laboratory accelerated conditions. The course of the photo-oxidative degradation process of that material was studied by FTIR spectroscopy both through quantitative measurements of changes in absorbance values at selected wave numbers and through measurements of surface area values for absorption bands which were separated by means of deconvolution. The use of both those procedures of quantitative determinations resulted in a general conclusion that the oxidation process was initiated from the very first moment of irradiation, and it produced ketones, acids, esters (intramolecular and of acetate type), peracids, peres…

Analysis of a GC/MS Thermal Desorption System with Simultaneous Sniffing for Determination of Off-Odor Compounds and VOCs in Fumes Formed during Extr…

2001

A thermal desorption equipment introducing volatile organic compounds (VOCs) into the gas chromatographic/ mass spectrometric system (GC/MS) with simultaneous sniffing (SNIFF) is a suitable method for identifying the volatile organic off-odor compounds formed during the extrusion coating process of low-density polyethylene. Fumes emitted during the extrusion coating process of three different plastic materials were collected at two different temperatures (285 and 315 degrees C) from an outgoing pipe and near an extruder. The VOCs of fumes were analyzed by drawing a known volume of air through the adsorbent tube filled with a solid adsorbent (Tenax GR). The air samples were analyzed by using…

Preparation of tungstophosphoric acid/cerium-doped NH2-UiO-66 Z-scheme photocatalyst: a new candidate for green photo-oxidation of dibenzothiophene a…

2021

International audience; The goal of this study was to introduce an effective visible-light induced photocatalytic system with a good ability for photocatalytic oxidative desulfurization (PODS) and denitrogenation (PODN) using molecular oxygen (O2) as an oxidant. In this regard, tungestophosphoric acid (PW12) was supported onto cerium-doped NH2-UiO-66 (PW12/Ce-NUiO-66) and employed for the photo-oxidation of dibenzothiophene (DBT) and quinoline (Qu). Herein, using cerium (Ce) as a “mediator” facilitated the separation of charge carriers, while NH2-UiO-66 remarkably enhanced the surface area with plentiful adsorption sites and shifted the adsorption edge of PW12to the visible region. The sum …

Effects of pyrolysis temperature on the hydrologically relevant porosity of willow biochar

2018

Biochar pore space consists of porosity of multiple length scales. In direct water holding applications like water storage for plant water uptake, the main interest is in micrometre-range porosity since these pores are able to store water that is easily available for plants. Gas adsorption measurements which are commonly used to characterize the physical pore structure of biochars are not able to quantify this pore-size range. While pyrogenetic porosity (i.e. pores formed during pyrolysis process) tends to increase with elevated process temperature, it is uncertain whether this change affects the pore space capable to store plant available water. In this study, we characterized biochar poro…