scholarly journals Characterization of Selected Polymeric Membranes Used in the Separation and Recovery of Palladium-Based Catalyst Systems

Membranes ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 166
Author(s):  
Bongani Michael Xaba ◽  
Sekomeng Johannes Modise ◽  
Bamidele Joseph Okoli ◽  
Mzimkhulu Ephraim Monapathi ◽  
Simphiwe Nelana
Keyword(s):  
Organic Solvent ◽  
Membrane Separation ◽  
Pure Water ◽  
Morphological Characterization ◽  
Polymeric Membrane ◽  
Separation Processes ◽  
Solute Permeability ◽  
Catalyst Systems ◽  
Almost All ◽  
Microscopy Characterization

Membrane separation processes tender a capable option for energy-demanding separation processes. Nanofiltration (NF) and reverse osmosis (RO) membranes are among the most explored, with a latent use in the chemical industry. In this study, four commercial membranes (NF90, NF270, BW30, and XLE) were investigated for their applicability based on the key structural performance characteristics in the recycling of Pd-based catalysts from Heck coupling post-reaction mixture. Pure water and organic solvent permeabilities, uncharged solute permeability, swelling, and catalyst rejection studies of the membranes were conducted as well as the morphological characterization using Fourier transform infrared, field emission gun scanning electron microscopy, and atomic force microscopy. Characterization results showed trends consistent with the manufactures’ specifications. Pure water and organic solvent fluxes generally followed the trend NF270 > NF90 > BW30 > XLE, with the solvent choice playing a major role in the separation process. Pd(PPh3)2Cl2 was well rejected by almost all membranes in 2-propanol; however, XLE rejects Pd(OAc)2 better at high pressure in acetonitrile. Our study, therefore, revealed that the separation and reuse of the two catalysts by NF90 at 10 bar resulted in 97% and 49% product yields with 52% and 10% catalyst retention for Pd(OAc)2 while Pd(PPh3)2Cl2. gave 87% and 6% yields with 58% and 36% catalyst retention in the first and second cycles, respectively. Considering, the influence of membrane–solute interactions in Pd-catalyst rejection, a careful selection of the polymeric membrane and solvent, a satisfactory separation, and recovery can be achieved.

scholarly journals Challenges of Membrane Technology in Biorefineries

2020 ◽  
Vol 24 (3) ◽  
Author(s):  
Lukka Thuyavan Yogarathinam ◽  
Ahmad Fauzi Ismail ◽  
Pei Sean Goh ◽  
Arthanareeswaran Gangasalam
Keyword(s):  
Membrane Fouling ◽  
Membrane Separation ◽  
Membrane Technology ◽  
Membrane Reactors ◽  
Biodiesel Production ◽  
Biofuel Production ◽  
Polymeric Membrane ◽  
Separation Processes ◽  
Significant Control ◽  
Membrane Engineering

Membrane separation processes have been deployed for downstream applications in biorefineries. This article discusses the challenges of membrane technology in purification of biofuels such as bioethanol, biodiesel and biogas. The significance of membrane technology are discussed towards the fractionation of lignocellulosic biomass for biofuel production.  The membrane reactors for biodiesel production were also studied. Limitation with respect to each individual processes on biofuel purification were also reported. The major limitation in membrane separation are membrane fouling and concentration polarization. Membrane engineering and process optimization are the viable tools to enhance the performance of membrane. Recently, inorganic nanofillers has significant control in alteration of polymeric membrane characteristics for the improvement of permeability and selectivity. This article would be an insight for researchers to understand the challenges of biorefinery membrane separation.

Composite Membrane and Evaluation on Separation Oil/Water

2020 ◽  
Vol 07 ◽  
Author(s):  
Luana Araújo de Oliveira ◽  
Meiry Gláucia Freire Rodrigues ◽  
Antonielly dos Santos Barbosa ◽  
Rochélia Silva Souza Cunha ◽  
Joseane Damasceno Mota
Keyword(s):  
Composite Membrane ◽  
Environmental Remediation ◽  
Membrane Separation ◽  
Pure Water ◽  
Water Flux ◽  
Polymeric Membrane ◽  
Water Separation ◽  
Oil Water ◽  
Cetyl Trimethyl Ammonium ◽  
Green Clay

Background: The generation of wastewater contaminated with organic compounds, release or spill into these water bodies can lead to serious environmental problems. The removal of chemical pollutants in water presents itself as one of the central issues regarding the issue of environmental remediation. In this sense, membranes, haves gained increasing importance in the environmental area. Objective: This present study aims to develop a composite membrane using UHMWPE/LDPE/CTAC-HGC to be used for oil/water separation of wastewater effluents. Methods: The polymeric membrane and composite membrane were prepared by uniaxial dry compaction and sintering. Both hard green clay (HGC) and hard green clay organophilized with cetyl trimethyl ammonium chloride (CTAC-HGC) were characterized by X-ray Diffraction (XRD), infrared spectroscopy (IR) and scanning electron microscopy (SEM). UHMWPE, polymeric membrane and composite membrane were characterized by XRD and SEM. Result: The water flux through the composite membrane was evaluated using pure water as a permeate. The potential of the composite membrane to separate oil-water emulsions was tested. Conclusions: The composite membrane showed excellent removal of the oil, exhibiting removal of more than 99.60 %, evidencing the process of composite membrane separation as an alternative technology for the treatment of oil.

Separation of Biologically Active Compounds by Membrane Operations

2017 ◽  
Vol 23 (2) ◽  
pp. 218-230 ◽  
Author(s):  
Xiaoying Zhu ◽  
Renbi Bai
Keyword(s):  
Energy Consumption ◽  
Bioactive Compounds ◽  
Membrane Fouling ◽  
Membrane Separation ◽  
Separation Efficiency ◽  
High Energy ◽  
Separation Processes ◽  
Membrane Processes ◽  
Separation Technology ◽  
Pressure Driven

Background: Bioactive compounds from various natural sources have been attracting more and more attention, owing to their broad diversity of functionalities and availabilities. However, many of the bioactive compounds often exist at an extremely low concentration in a mixture so that massive harvesting is needed to obtain sufficient amounts for their practical usage. Thus, effective fractionation or separation technologies are essential for the screening and production of the bioactive compound products. The applicatons of conventional processes such as extraction, distillation and lyophilisation, etc. may be tedious, have high energy consumption or cause denature or degradation of the bioactive compounds. Membrane separation processes operate at ambient temperature, without the need for heating and therefore with less energy consumption. The “cold” separation technology also prevents the possible degradation of the bioactive compounds. The separation process is mainly physical and both fractions (permeate and retentate) of the membrane processes may be recovered. Thus, using membrane separation technology is a promising approach to concentrate and separate bioactive compounds. Methods: A comprehensive survey of membrane operations used for the separation of bioactive compounds is conducted. The available and established membrane separation processes are introduced and reviewed. Results: The most frequently used membrane processes are the pressure driven ones, including microfiltration (MF), ultrafiltration (UF) and nanofiltration (NF). They are applied either individually as a single sieve or in combination as an integrated membrane array to meet the different requirements in the separation of bioactive compounds. Other new membrane processes with multiple functions have also been developed and employed for the separation or fractionation of bioactive compounds. The hybrid electrodialysis (ED)-UF membrane process, for example has been used to provide a solution for the separation of biomolecules with similar molecular weights but different surface electrical properties. In contrast, the affinity membrane technology is shown to have the advantages of increasing the separation efficiency at low operational pressures through selectively adsorbing bioactive compounds during the filtration process. Conclusion: Individual membranes or membrane arrays are effectively used to separate bioactive compounds or achieve multiple fractionation of them with different molecule weights or sizes. Pressure driven membrane processes are highly efficient and widely used. Membrane fouling, especially irreversible organic and biological fouling, is the inevitable problem. Multifunctional membranes and affinity membranes provide the possibility of effectively separating bioactive compounds that are similar in sizes but different in other physical and chemical properties. Surface modification methods are of great potential to increase membrane separation efficiency as well as reduce the problem of membrane fouling. Developing membranes and optimizing the operational parameters specifically for the applications of separation of various bioactive compounds should be taken as an important part of ongoing or future membrane research in this field.

Application of membrane separation processes in phosphorus recovery: A review

2021 ◽  
Vol 767 ◽  
pp. 144346
Author(s):  
Xiang Li ◽  
Shuting Shen ◽  
Yuye Xu ◽  
Ting Guo ◽  
Hongliang Dai ◽  
...  
Keyword(s):  
Membrane Separation ◽  
Phosphorus Recovery ◽  
Separation Processes

scholarly journals Analysis of ethanol dehydration using membrane separation processes

2020 ◽  
Vol 15 (1) ◽  
pp. 122-132 ◽  
Author(s):  
Carolina Conde-Mejía ◽  
Arturo Jiménez-Gutiérrez
Keyword(s):  
Capital Investment ◽  
Membrane Separation ◽  
Biomass Pretreatment ◽  
Ethanol Dehydration ◽  
Purification Step ◽  
Silica Membrane ◽  
Separation Processes ◽  
Fermentation Processes ◽  
Vapor Permeation ◽  
Type Zeolite

AbstractAfter the biomass pretreatment and fermentation processes, the purification step constitutes a major task in bioethanol production processes. The use of membranes provides an interesting choice to achieve high-purity bioethanol. Membrane separation processes are generally characterized by low energy requirements, but a high capital investment. Some major design aspects for membrane processes and their application to the ethanol dehydration problem are addressed in this work. The analysis includes pervaporation and vapor permeation methods, and considers using two types of membranes, A-type zeolite and amorphous silica membrane. The results identify the best combination of membrane separation method and type of membrane needed for bioethanol purification.

Biofilms: their structure, activity, and effect on membrane filtration

2005 ◽  
Vol 51 (6-7) ◽  
pp. 181-192 ◽  
Author(s):  
Z. Lewandowski ◽  
H. Beyenal
Keyword(s):  
Membrane Filtration ◽  
Membrane Separation ◽  
Separation Processes ◽  
Membrane Cleaning ◽  
Underlying Assumption ◽  
Structure Activity ◽  
Membrane Biofouling ◽  
Flux Decline ◽  
Cleaning Procedures ◽  
Near Future

The goal of this presentation is to identify biofouling mechanisms that cause undesirable effects to the membrane separation processes of flux decline and pressure drop. The underlying assumption of this presentation is that biofouling is unavoidable and that the operator cannot eliminate it entirely. This premise justifies research efforts toward understanding the mechanisms by which biofouling affects the membrane processes, rather than expecting that technology can entirely eliminate membrane biofouling in the near future. An improved understanding of biofouling mechanisms may lead to better membrane design, better membrane modules, and better membrane cleaning procedures.

APPLICATION OF ULTRASOUND IN MEMBRANE SEPARATION PROCESSES: A REVIEW

2006 ◽  
Vol 22 (3) ◽  
Author(s):  
Shobha Muthukumaran ◽  
Sandra E. Kentish ◽  
Geoff W. Stevens ◽  
Muthupandian Ashokkumar
Keyword(s):  
Membrane Separation ◽  
Separation Processes

Membrane Separation Processes

2019 ◽  
pp. 243-258
Author(s):  
Louis Theodore ◽  
R. Ryan Dupont
Keyword(s):  
Membrane Separation ◽  
Separation Processes
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