Search results for "Supercritical"

Extraction of lapachol from Tabebuia avellanedae wood with supercritical CO2: an alternative to Soxhlet extraction?

2003

The solubility of lapachol in supercritical CO2 was determined at 40°C and pressures between 90 and 210 bar. Supercritical fluid extraction of lapachol and some related compounds by CO2 from Tabebuia avellanedae wood is compared to Soxhlet extraction with different solvents. A standard macroscale (100-200 g wood) and a microscale (~10 mg wood) experimental setup are described and their results are compared. The latter involved direct spectrophotometric quantification in a high-pressure autoclave with an integrated optical path and a magnetic stirrer, fitted directly into a commercial spectrophotometer. The relative amount of lapachol extracted by supercritical CO2 at 40°C and 200 bar was ab…

Advances and Perspectives of Supercritical Fluid Technology

2013

1 Dipartimento di Ingegneria Industriale, Universita di Salerno, Salerno, 84084 Fisciano, Italy 2 Departamento de Ingenieŕia Quimica, Universidad de Castilla-La Mancha, 13004 Ciudad Real, Spain 3 Department of Agricultural, Food & Nutritional Sciences, University of Alberta, Edmonton, AB, Canada T6G 2P5 4Dipartimento di Ingegneria Chimica, Gestionale, Informatica, Meccanica, Universita di Palermo, 90128 Palermo, Italy

Valorization of waste solvents through supercritical water gasification

2017

The supercritical water gasification of various organic species belonging to the groups of organic acids, aldehydes, ketones, alcohols and phenols, has been studied as a possible waste disposal method for polluted water stream produced in industries and laboratories. Gasification has been investigated using a 200 cm3 down flow reactor working continuously at 24 MPa and 660 °C. Supercritical water gasification (SCWG) is effective for the syngas production at very high conversion rate for all the species investigates, but phenol. Phenol, when mixed with other species, has an inhibitory effect of the radical chain gasification mechanism that dramatically reduced the gasification performance. …

MULTIFUNCTION REACTOR

2022

Described herein is a reactor (1) includes: a first reaction volume (V1), a second reaction volume (V2), wherein: the first reaction volume (V1) is in fluid communication with an inlet port for an oxidizer agent (OX_IN), an inlet port for at least one first reactant (R1_IN) and an outlet port for at least one reaction product (P1_OUT), said second reaction volume (V2) is in fluid communication with an inlet port for at least one second reactant (R2_IN), an outlet port for at least one second reaction product (P2_OUT) and is furthermore in thermal exchange relationship with said first reaction volume (V1), wherein, during operation, in said first reaction volume (V1) an oxidation reaction oc…

Extraction Methods of Essential Oils From Herbs and Spices

2017

International audience; This chapter describes both conventional and non‐conventional extraction methods of essential oils (EOs) from herbs and spices. Although hydrodistillation, steam distillation and solvent extraction are the most applied methods, several non‐conventional technologies have been evaluated, especially in respect to EO recovery, and a great potential has been attributed to these non‐conventional methods. For instance, ultrasound, microwave, supercritical fluid, pulsed electric fields, ohmic‐heating and microwave (MW) extraction techniques applied alone or combined with other techniques are potent tools to obtain EOs in a 'green' way from natural resources such as aromatic …

Modification of PVDF nanoparticles by controlled free radical graft copolymerization in supercritical carbon dioxide

2014

PVDF (polyvinylidenefluoride) membranes are widely used in microfiltration (MF) and ultrafiltration (UF) due to their excellent processability, chemical resistance, well-controlled porosity, and good thermal properties [1]. Moreover this polymer is also frequently adopted in bio-medical devices owing to its good biocompatibility [2]. On the other hand, the use of PVDF membranes in biomedical applications is limited to some extent by the hydrophobicity of their exposed area, which mainly arises from the nature of the pore surface. Prompted by these considerations in the present work we have studied the modification of PVDF nanoparticles with hydroxyethylmethacrylate (HEMA) thus obtaining a m…

Impact of the Extraction Method on the Chemical Composition and Antioxidant Potency of Rosmarinus officinalis L. Extracts

2023

Rosmarinus officinalis L. is a dietary source that produces polyphenols as secondary metabolites. These natural compounds with potent antioxidant abilities are increasingly recommended as a supplement to inhibit oxidative stress. In the current work, we evaluated the impact of the extraction method on the chemical composition of R. officinalis extract, especially on the content of carnosic (CA) and rosmarinic (RA) acids using UPLC-MS-DAD as well as on their antioxidant potency. Four extracts of Tunisian rosemary were obtained from non-conventional extraction techniques:ultrasound-assisted extraction (UAE),supercritical extraction (SFE) and UAE and SFE combined ((UAE-SFE(I), UAE-SFE(II)). Th…

Sterilization of three-dimensional tissue engineering scaffolds by supercritical carbon dioxide

2014

Medical devices, implants or patient-care equipment that will come into intimate contact with a patient must be effectively decontaminated to prevent infection or disease transmission. Non-sterile devices have significant ramifications for patient morbidity and mortality and two processes must be undertaken in order to make an item acceptable for use or implantation: cleaning and disinfection (or sterilization) [1]. Sterilization is the destruction of living organisms, and must be done without damaging the material surface and without compromising the bulk material strength or biocompatibility of implantable device. Common sterilization processes include steam autoclaving, gamma irradiation…

A one-pot method to enhance dissolution rate of low solubility drug molecules using dispersion polymerization in supercritical carbon dioxide

2009

Preparation of pH sensitive poly(vinilydenefluoride) porous membranes by grafting of acrylic acid assisted by supercritical carbon dioxide

2010

Aim of this work is to study the preparation of pH sensitive membranes for biomedical applications via thermal induced graft polymerization of acrylic acid (AA) on poly(vinilydenefluoride) (PVDF) assisted by supercritical carbon dioxide (scCO2). Using scCO2 as a solvent and swelling agent, the monomer and initiator (benzoyl peroxide) could diffuse faster and distribute more uniformly into the polymer matrix. A better control of the final molecular architecture should be achieved because bimolecular grafting reactions are accelerated with respect to chain degradation processes. Commercial hydrophobic PVDF porous matrixes were selected as model membranes. Grafted polymers were characterized b…