Separation Of Organic Substances Research Articles

Pyrolysis mechanism and recycling strategy of end-of-life photovoltaic modules based on the experiment and the density functional theory

Recent advancements in renewable energy have enabled a reduction of fossil fuel usage. However, the so-called energy waste, such as end-of-life (EoL) photovoltaic (PV) modules, has become a simultaneous emerging issue in the field of solid waste management. Debonding of ethylene-vinyl-acetate (EVA) copolymer is critical for recycling EoL PV modules. The separation of organic substances may be done effectively using pyrolysis technology. Therefore, in this work we investigated the pyrolysis characteristic and mechanism of EVA. Based on TG, TG-FTIR, and Py-GC/MS, the pyrolysis products and pyrolysis characteristics of EVA were examined. Activation energies and reaction mechanisms were determined through iso-conversional model-free and model-fitting methods. Combined with density functional theory (DFT) calculations, the pyrolysis mechanism of EVA was discussed. Our research shows that the pyrolysis technology can almost completely decompose EVA without residue and the EVA pyrolysis can be divided into two stages. Combined with DFT calculation, it was found that in the stage Ⅰ, acetoxy was removed to generate acetic acid, and in the stage Ⅱ, the main chain of EVA was broken to generate olefins. The recycling strategy based on two-step pyrolysis of Eol PV modules was accordingly proposed.

Highly Efficient Separation of Organic Substances from High Salinity Brine by Nanofiltration

Highly Efficient Separation of Organic Substances from High Salinity Brine by Nanofiltration

Mechanism Analysis for Separation of Cyclohexane and tert-Butanol System via Ionic Liquids as Extractants and Process Optimization

Ionic liquids (ILs) are used in separation of organic substances in industry. In order to screen suitable ILs for industrial separation, the interaction between molecules is studied based on the ex...

Determination of organic substances with different boiling points in aqueous media by capillary gas-liquid chromatography

Studies were conducted on separation of organic substances with different boiling points and polarity when simultaneously present in water by capillary gas-liquid chromatography on a Kristall 2000 m chromatograph. The effect of the column phase and temperature conditions on the separation factor and component exit time was investigated. Column temperature programming was used to reduce the component, especially heavy component, retention time. The chromatography regime was selected and a fast method was developed for determining components with different volatility in water during one analysis with sufficiently high reproducibility and reliability of the results. It was shown that the time of the analysis decreased by more than two times with the same accuracy as with the standard methods. The method can be recommended for fast analysis of wastewaters for making a decision on the treatment method.

Application of poly(butadiene‐co‐acrylic acid)–sucrose as gel in the separation of different substances

AbstractThe synthesis of a new hydrophobic gel by reacting cooligomer of butadiene and acrylic acid (Mw 4500) with sucrose crosslinking in best conditions is described. Application of this new gel swelled in different organic solvents is studied. Separation of organic substances in benzene was achieved with higher retention of more polar substances. By this way, cholesterol was separated from lecithin, acrylic acid from polybutadiene with terminal carboxylic groups, and metals such as copper from organic solvents.

Preparation and application of β-diketone bonded phases in high-pressure liquid chromatography

Chemically bonded β-diketone phases were prepared by reacting silylated silica gel with diketene. The potential of the resulted immobilized chelates as stationary phases in high-pressure liquid chromatography was illustrated by using this material for the separation of organic substances like o-, m- and p-nitroanilines, aromatic carboxylic acids, urea herbicides as well as o-, m- and p-aminophenols.

Möglichkeiten des Einsatzes der Ultrafiltration und der reversiblen Osmose zur Gewinnung und Aufarbeitung löslicher Inhaltsstoffe aus Prozeßwässern der Stärkeindustrie

AbstractPossibilities for the Use of Ultra Filtration and Reverse Osmosis for Extraction and Processing of Soluble Constituents from Process Water in Starch Industries. The theoretical principles of ultra filtration and reversible osmosis are explained and the units which are in practical use are described (flat membrane units, hollow fibre units, and tubular membrane units). A comparison shows that tubular membrane units can be used successfully for the processing of process water in starch factories in view of reduction of water pollution and recovery of dissolved solids. Separation of organic substances from wheat flour extract and potato fruit water is done in similar way. COD (chemical oxygen demand) of the permeate is directly proportional to the COD of the concentrate. It is pointed out that application of membrane filtration for isothermal, selective and continuous separation of dissolved solids is restricted by the short life and low flux rate of the membranes.

Preparative gas-liquid chromatography with increased efficiency

1. The optimum conditions for the preparative gas-chromatographic separation of organic substances with an efficiency of up to 2000 theoretical plates, with a simultaneous load of up to 1–2 g, were developed. 2. Designs of an accessible preparative chromatograph for the separation of unstable compounds were suggested, and the possibility of using it for the separation of organic substances of various classes was demonstrated. 3. The promise of the use of sodium chloride as the solid phase for the preparative gas-chromatographic separation of unstable compounds was demonstrated.