scholarly journals Liquid Membranes for Efficient Recovery of Phenolic Compounds Such as Vanillin and Catechol

Membranes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
Sandra Pavón ◽  
Luisa Blaesing ◽  
Annika Jahn ◽  
Ines Aubel ◽  
Martin Bertau
Keyword(s):  
Chemical Structure ◽  
Lignin Degradation ◽  
Liquid Membrane ◽  
Side Reactions ◽  
Liquid Membranes ◽  
Organic Mixture ◽  
Initial Ph ◽  
Cyanex 923 ◽  
Efficient Recovery ◽  
Set Up

Investigations were carried out to obtain different lignin monomers such as vanillin and catechol as efficiently as possible, to prevent side reactions e.g., during lignin degradation. Therefore, extraction experiments were performed to determine the influence of parameters such as initial pH in the aqueous phase, organic phases containing alcohols or solvating extractants, and monomer concentrations. Cyanex 923 (Cy923) and tri-n-butyl-phosphat (TBP) diluted in kerosene were the organic phases chosen to evaluate the transport of vanillin because of their high efficiencies (>76.8%) and suitability in membrane technologies. The most efficient vanillin transport was accomplished with Cy923, as > 90% of vanillin was transferred after 5 h. However, the permeability coefficient at carrier concentration of > 0.48 mol/L was influenced not only by the diffusion but also by the organic mixture viscosity. Thus, this concentration was used in the membrane experiment containing a mixture of vanillin and catechol in the feed phase. Catechol was transported about 7% faster to the receiving phase than vanillin, presumably due to its chemical structure. Side reactions were avoided using the current liquid membrane set-up, allowing the further industrial application of an entire process, which, e.g., recovers vanillin from enzymatic lignin conversion by membrane technology.

scholarly journals UVA-LED Technology’s Treatment Efficiency and Cost in a Competitive Trial Applied to the Photo-Fenton Treatment of Landfill Leachate

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1026
Author(s):  
Javier Tejera ◽  
Antonio Gascó ◽  
Daphne Hermosilla ◽  
Víctor Alonso-Gomez ◽  
Carlos Negro ◽  
...  
Keyword(s):  
Landfill Leachate ◽  
Mercury Vapor ◽  
Cod Removal ◽  
Treatment Efficiency ◽  
Alternative Source ◽  
Effluent Quality ◽  
Radiation Sources ◽  
Initial Ph ◽  
Pre Treatment ◽  
Set Up

The objective of this trial was to assess the application of UVA-LED technology as an alternative source of irradiation for photo-Fenton processes, aiming to reduce treatment costs and provide a feasible treatment for landfill leachate. An optimized combination of coagulation with ferric chloride followed by photo-Fenton treatment of landfill leachate was optimized. Three different radiation sources were tested, namely, two conventional high-pressure mercury-vapor immersion lamps (100 W and 450 W) and a custom-designed 8 W 365 nm UVA-LED lamp. The proposed treatment combination resulted in very efficient degradation of landfill leachate (COD removal = 90%). The coagulation pre-treatment removed about 70% of the COD and provided the necessary amount of iron for the subsequent photo-Fenton treatment, and it further favored this process by acidifying the solution to an optimum initial pH of 2.8. The 90% removal of color improved the penetration of radiation into the medium and by extension improved treatment efficiency. The faster the Fenton reactions were, as determined by the stoichiometric optimum set-up reaction condition of [H2O2]0/COD0 = 2.125, the better were the treatment results in terms of COD removal and biodegradability enhancement because the chances to scavenge oxidant agents were limited. The 100 W lamp was the least efficient one in terms of final effluent quality and operational cost figures. UVA-LED technology, assessed as the application of an 8 W 365 nm lamp, provided competitive results in terms of COD removal, biodegradability enhancement, and operational costs (35–55%) when compared to the performance of the 450 W conventional lamp.

Ionic Liquids as Green Solvents for the Treatment of Endocrine Disrupting Compounds Using Liquid Membranes

2016 ◽  
Vol 5 (6) ◽  
pp. 258-270
Author(s):  
Santhi Raju Pilli ◽  
Tamal Banerjee ◽  
Kaustubha Mohanty
Keyword(s):  
Endocrine Disruptors ◽  
Liquid Membrane ◽  
Endocrine Disrupting Compounds ◽  
Membrane Technology ◽  
Liquid Membranes ◽  
Green Solvents ◽  
Endocrine Disrupting ◽  
Water And Wastewater ◽  
Living Organisms ◽  
Supported Ionic Liquid Membranes

Presence of endocrine disruptors in water and wastewater pose a serious threat to all living organisms. The removal of such disruptors is a major challenge especially most of the time they are present in trace amounts. Several technologies were tested to see if 100% removal can be achieved. Most of the existing technologies failed to achieve the target and have their own limitations. Membrane technology and especially liquid membrane technology has of late generated extreme interest among the researchers working with pollutants in trace amounts. In this work, experiments on three endocrine disruptors such as BPA, PCP and ES are carried out using supported ionic liquid membranes to see their removal efficiencies. The effects of various process parameters were studied to optimize them.

scholarly journals New way of anionic ring-opening copolymerization of β-butyrolactone and ε-caprolactone: determination of the reaction course

2020 ◽  
Vol 27 (12) ◽  
Author(s):  
Zbigniew Grobelny ◽  
Justyna Jurek-Suliga ◽  
Sylwia Golba
Keyword(s):  
Ring Opening ◽  
Chemical Structure ◽  
Side Reactions ◽  
Complexing Agent ◽  
Critical Approach ◽  
Anionic Ring ◽  
Tetrahydrofuran Solution ◽  
End Group ◽  
C Nmr

Abstract Poly(ε-caprolactone)-block-poly(β-butyrolactone) copolymers were prepared in two-step synthesis. Firstly, poly(ε-caprolactone) (PCL) was obtained by anionic ring-opening polymerization of CL initiated with anhydrous KOH activated 12-crown-4 cation complexing agent. Reaction was carried out in tetrahydrofuran solution and argon atmosphere at room temperature. Then, β-butyrolactone (BL) and 18-crown-6 were added to the system, resulting in PCL-block-PBL copolymer, which contains after methylation hydroxyl starting group and methyl ester end group. The main product was contaminated with PCL and PBL homopolymers formed in a side reactions. 13C NMR technique was used for determination of chemical structure of polymers obtained. The course of the studied processes was proposed. MALDI-TOF technique was used to reveal the macromolecules’ architecture where several series were found. The identified series shown that mainly copolymeric macromolecules were formed with scare contribution of homopolymeric polybutyrolactone with trans-crotonate starting groups and polycaprolactone, which is congruent with the proposed reaction mechanism. Moreover, critical approach concerning previously reported PCL-block-PBL copolymer synthesis by use of NaH as initiator was also presented.

Extraction and permeation studies of Cd(II) in acidic and neutral chloride media using Cyanex 923 on supported liquid membrane

2009 ◽  
Vol 96 (1-2) ◽  
pp. 81-87 ◽  
Author(s):  
N.S. Rathore ◽  
A. Leopold ◽  
A.K. Pabby ◽  
A. Fortuny ◽  
M.T. Coll ◽  
...  
Keyword(s):  
Liquid Membrane ◽  
Supported Liquid Membrane ◽  
Permeation Studies ◽  
Cyanex 923

Degradation of bromamine acid by nanoscale zero-valent iron (nZVI) supported on sepiolite

2012 ◽  
Vol 66 (12) ◽  
pp. 2539-2545 ◽  
Author(s):  
Xuening Fei ◽  
Lingyun Cao ◽  
Lifeng Zhou ◽  
Yingchun Gu ◽  
Xiaoyang Wang
Keyword(s):  
Ph Value ◽  
Energy Dispersive Spectrometer ◽  
Zero Valent Iron ◽  
Mass Ratio ◽  
Initial Concentration ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Initial Ph ◽  
Set Up

Sepiolite, a natural nano-material, was chosen as a carrier to prepare supported nanoscale zero-valent iron (nZVI). The effects of preparation conditions, including mass ratio of nZVI and activated sepiolite and preparation pH value, on properties of the supported nZVI were investigated. The results showed that the optimal mass ratio of nZVI and sepiolite was 1.12:1 and the optimal pH value was 7. The supported nZVI was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and energy dispersive spectrometer (EDS), and furthermore an analogy model of the supported nZVI was set up. Compared with the nZVI itself, the supported nZVI was more stable in air and possessed better water dispersibility, which were beneficial for the degradation of bromamine acid aqueous solution. The degradation characteristics, such as effects of supported nZVI dosage, initial concentration and initial pH value of the solution on the decolorization efficiency were also investigated. The results showed that in an acidic environment the supported nZVI with a dosage of 2 g/L showed high activity in the degradation of bromamine acid with an initial concentration of 1,000 mg/L, and the degree of decolorization could reach up to 98%.

Electrodeposition of Cobalt and Lead in the Hybrid Liquid Membrane - Electrodialysis-Electrolysis Process

2016 ◽  
Vol 721 ◽  
pp. 399-403 ◽  
Author(s):  
Tatiana Sadyrbaeva
Keyword(s):  
Liquid Membrane ◽  
Nitric Acid Concentration ◽  
Feed Solution ◽  
Bulk Liquid ◽  
Liquid Membranes ◽  
Dilute Solutions ◽  
Cathodic Electrodeposition ◽  
Fine Grained ◽  
Fine Grained Structure ◽  
Effective Transfer

A novel method for Co (II) and Pb (II) recovery from acidic solutions is presented. The extraction of Co (II) and Pb (II) ions using the bulk liquid membranes during a galvanostatic electrodialysis process accompanied by cathodic electrodeposition of the metals was studied. Solutions of di (2-ethylhexyl) phosphoric acid (D2EHPA) with admixtures of tri-n-octylamine (TOA) in 1,2-dichloroethane were used as the liquid membranes. Effects of current density, Co (II) and Pb (II) concentrations in the feed solution, sulfuric or nitric acid concentration in the feed solution, D2EHPA and TOA concentration in the liquid membrane, of the type and concentration of acid in the cathodic solution were studied, and optimal conditions were determined. It is demonstrated that a practically complete (98-99%) removal of Co (II) and Pb (II) from the feed solutions containing 0.01 mol∙L-1 CoSO4 or 0.01 mol∙L-1 Pb (NO3)2 is achieved during 1.0 − 4.0 h of electrodialysis. A possibility of effective transfer of Pb (II) into dilute solutions of perchloric and nitric acids was demonstrated. The liquid membranes ensure the recovery of Co (II) ions into dilute solutions of perchloric, sulphuric, hydrochloric and nitric acids. Adherent, compact cobalt and lead electrodeposits with a fine-grained structure were obtained in the studied systems.

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