Effect of temperature on the heat treatment to recover green solvent from emulsion liquid membranes used in the extraction of Cr(VI)

Author(s):  
Katia Anarakdim ◽  
María Matos ◽  
Angel Cambiella ◽  
Ounissa Senhadji-Kebiche ◽  
Gemma Gutiérrez
Membranes ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 76 ◽  
Author(s):  
Katia Anarakdim ◽  
Gemma Gutiérrez ◽  
Ángel Cambiella ◽  
Ounissa Senhadji-Kebiche ◽  
María Matos

The stability of emulsion liquid membranes (ELMs) and their ability to extract Cr(VI) were investigated. The objective of this study is to compare different ELM formulations using combinations of two hydrophilic (Tween 20 and Tween 80) and two lipophilic (polyglycerol polyricinoleate (PGPR) and Span 80) emulsifiers. TOPO (tri-n-octylphosphine oxide) as a carrier and a green solvent (sunflower oil) were used to provide high extraction efficiency of Cr(VI). All these double emulsions were characterized in droplet size distribution, zeta potential, visual inspection with a microscope, and stability. The best formulation was obtained with PGPR as the inner stabilizer and Tween 80 as the outer stabilizer, leading to Cr(VI) ion removal efficiency of up to 96%.


2017 ◽  
Vol 68 (10) ◽  
pp. 2320-2324
Author(s):  
Mariana Mateescu ◽  
Sanda Maria Doncea ◽  
Irina Chican ◽  
Cristina Lavinia Nistor ◽  
Ioneta Codrina Bujanca

The aim of this work is the synthesis of calcium carbonate (CaCO3) nano and microparticles and their application as biomaterials (vehicles) for the sustained release of doxycycline. CaCO3 micro particles were synthesized by water-in oil (W/O) emulsion method using emulsion liquid membranes with bis (2-ethylhexyl) phosphate (D2EHPA) as carrier, Span 80 as surfactant, and toluene and kerosene as organic solvents. The aqueous phases contained 1 M CaCl2, and 1 M Na2CO3, respectively. The Dynamic Light Scattering (DLS) data showed CaCO3 particles with sizes ranging from around 100 nm to 3500 nm. The CaCO3 particles with the average diameters around 600 nm attained an adsorbtion of doxycycline of maximum 97.9%, and a slow and steady release with a cumulative value of approximative 50% after ten days.


2017 ◽  
Vol 17 (4) ◽  
pp. 13-18
Author(s):  
A. Bajwoluk ◽  
P. Gutowski

Abstract The results of research on the effect of the type of cooling agent used during heat treatment and thermal-chemical treatment on the formation of temperature gradient and stress-deformation distribution in cast pallets, which are part of furnace accessories used in this treatment, are disclosed. During operation, pallets are exposed to the effect of the same conditions as the charge they are carrying. Cyclic thermal loads are the main cause of excessive deformations or cracks, which after some time of the cast pallet operation result in its withdrawal due to damage. One of the major causes of this damage are stresses formed under the effect of temperature gradient in the unevenly cooled pallet construction. Studies focused on the analysis of heat flow in a charge-loaded pallet, cooled by various cooling agents characterized by different heat transfer coefficients and temperature. Based on the obtained temperature distribution, the stress distribution and the resulting deformation were examined. The results enabled drawing relevant conclusions about the effect of cooling conditions on stresses formed in the direction of the largest temperature gradient.


Membranes ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 66
Author(s):  
Gerardo León ◽  
Elisa Gómez ◽  
Beatriz Miguel ◽  
Asunción María Hidalgo ◽  
María Gómez ◽  
...  

Emulsion liquid membranes have been successfully used for the removal of different types of organic and inorganic pollutants by means of carrier-mediated transport mechanisms. However, the models that describe the kinetics and transport of such mechanisms are very complex due to the high number of model parameters. Starting from an analysis of the similarity between the elemental mechanisms of carrier-mediated transport in liquid membranes and of transport in adsorption processes, this paper presents an experimental analysis of the possibility of applying kinetic and mechanistic models developed for adsorption to carrier-mediated transport in emulsion liquid membranes. We study the removal of a target species, in this case, Cu(II), by emulsion liquid membranes containing membrane phase solutions of benzoylacetone (carrier agent), Span 80 (emulsifying agent) and kerosene (diluent), and hydrochloric acid as a stripping agent in the product phase. The experimental results fit the pseudo-second-order adsorption kinetic model, showing good relationships between the experimental and model parameters. Although both Cu(II) diffusion through the feed/membrane interface boundary layer and complex Cu-benzoylacetone diffusion through the membrane phase controls Cu(II) transport, it is the former step that mainly controls the transport process.


2012 ◽  
Vol 6 (3-4) ◽  
Author(s):  
Dragan Vujadinović ◽  
Željka Marjanović-Balaban

The real importance of meat in human nutrition has been defined during the last century. Professional and scientific publications of the twentieth century are often written about the nutritional value of meat. Thermal processing of meat is as old as civilization itself. Meat drying as a procedure for a longer shelf life, probably first appeared as a result of some accident in which the fresh meat has been exposed to heat. The first works about the problems of heat treatment of pork were published in the 1950s.The aim of this paper was to investigate the effect of temperature and different methods of heat treatment on chemical properties of processed pork meat. To determine the optimal conditions for various heat treatment processes, in this paper, meat processing was performed at different temperatures, and set the temperature range from 51 ºC to 100 ºC. Therefore, the meat is processed by dry heat treatment (roasting) and cooking in water (at atmospheric pressure). Then, the change of chemical composition of processed meat was noted (moisture content, ash, fat, protein, micronutrients).


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