scholarly journals Architecture and mass transport properties of graphene-based membranes

JMST Advances ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 77-88
Author(s):  
Heechan Yang ◽  
Jonghyun Baek ◽  
Hyung Gyu Park
Keyword(s):  
Water Treatment ◽  
Mass Transport ◽  
Membrane Separation ◽  
Transport Phenomena ◽  
Dimensional Accuracy ◽  
Interlayer Spacing ◽  
Water Desalination ◽  
Separation Processes ◽  
Research Activities ◽  
Dynamics Simulations

Abstract A recently rising question of the applicability of two-dimensional (2D) materials to membranes of enhanced performance in water technology is drawing attention increasingly. At the center of the attention lies graphene, an atom-thick 2D material, for its readiness and manufacturability. This review presents an overview of recent research activities focused on the fundamental mass transport phenomena of two feasible membrane architectures from graphene. If one could perforate pores in a pristine impermeable graphene sheet with dimensional accuracy, the perforated 2D orifice would show unrivaled permeation of gases and liquids due to the 0D atomic barrier. If possibly endowed with selectivity, the porous graphene orifice would avail potentially for membrane separation processes. For example, it is noteworthy that results of molecular dynamics simulations and several early experiments have exhibited the potential use of the ultrathin permeable graphene layer having sub-nanometer-sized pores for a water desalination membrane. The other membrane design is obtainable by random stacking of moderately oxidized graphene platelets. This lamellar architecture suggests the possibility of water treatment and desalination membranes because of subnanometric interlayer spacing between two adjacent graphene sheets. The unique structure and mass transport phenomena could enlist these graphene membrane architectures as extraordinary membrane material effective to various applications of membrane technology including water treatment. Graphic abstract

scholarly journals Bibliometric approach to the perspectives and challenges of membrane separation processes to remove emerging contaminants from water

2020 ◽  
Vol 82 (9) ◽  
pp. 1721-1741
Author(s):  
Jéssica Stefanello Cadore ◽  
Lucas Fernando Fabro ◽  
Thuany Garcia Maraschin ◽  
Nara Regina de Souza Basso ◽  
Marçal José Rodrigues Pires ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Water Treatment ◽  
Emerging Contaminants ◽  
Membrane Separation ◽  
High Surface ◽  
High Surface Area ◽  
Industrial Applications ◽  
Mechanical Resistance ◽  
Separation Processes ◽  
Research Attention

Abstract The presence of contaminants in water is concerning due to the potential impacts on human health and the environment, and ingested contaminants cause harm in various ways. The conventional water treatment systems are not efficient to remove these contaminants. Therefore, novel techniques and materials for the removal of contaminants are increasingly being developed. The separation process using modified membranes can remove these micropollutants; therefore, they have attracted significant research attention. Among the materials used for manufacturing of these membranes, composites based on graphene oxide and reduced graphene oxide are preferred owing to their promising properties, such as mechanical resistance, thermal and chemical stability, antifouling capacity, water permeability, high thermal and electrical conductivity, high optical transmittance and high surface area. Membrane separation processes (MSP) can be used as secondary or tertiary treatment during the supply of wastewater. However, the efficient and accessible applications of these technologies are challenging. This study aims to demonstrate the main concepts of membrane separation processes and their application in the removal of emerging contaminants. This study reports bibliometric mapping, relevant data on studies using membranes as water treatment processes, and their viability in industrial applications. The main challenges and perspectives of these technologies are discussed in detail as well.

scholarly journals Polydopamine Functionalized Graphene Oxide as Membrane Nanofiller: Spectral and Structural Studies

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 86
Author(s):  
Abedalkader Alkhouzaam ◽  
Hazim Qiblawey ◽  
Majeda Khraisheh
Keyword(s):  
Contact Angle ◽  
Graphene Oxide ◽  
Self Assembly ◽  
Membrane Separation ◽  
Interlayer Spacing ◽  
Functionalized Graphene ◽  
Separation Processes ◽  
Functionalized Graphene Oxide ◽  
Assembly Technique ◽  
Amine Groups

High-degree functionalization of graphene oxide (GO) nanoparticles (NPs) using polydopamine (PDA) was conducted to produce polydopamine functionalized graphene oxide nanoparticles (GO-PDA NPs). Aiming to explore their potential use as nanofiller in membrane separation processes, the spectral and structural properties of GO-PDA NPs were comprehensively analyzed. GO NPs were first prepared by the oxidation of graphite via a modified Hummers method. The obtained GO NPs were then functionalized with PDA using a GO:PDA ratio of 1:2 to obtain highly aminated GO NPs. The structural change was evaluated using XRD, FTIR-UATR, Raman spectroscopy, SEM and TEM. Several bands have emerged in the FTIR spectra of GO-PDA attributed to the amine groups of PDA confirming the high functionalization degree of GO NPs. Raman spectra and XRD patterns showed different crystalline structures and defects and higher interlayer spacing of GO-PDA. The change in elemental compositions was confirmed by XPS and CHNSO elemental analysis and showed an emerging N 1s core-level in the GO-PDA survey spectra corresponding to the amine groups of PDA. GO-PDA NPs showed better dispersibility in polar and nonpolar solvents expanding their potential utilization for different purposes. Furthermore, GO and GO-PDA-coated membranes were prepared via pressure-assisted self-assembly technique (PAS) using low concentrations of NPs (1 wt. %). Contact angle measurements showed excellent hydrophilic properties of GO-PDA with an average contact angle of (27.8°).

Membrane separation processes tackle textile waste-water treatment

2001 ◽  
Vol 2001 (130) ◽  
pp. 9-11 ◽  
Author(s):  
A. Bottino ◽  
G. Capannelli ◽  
G. Tocchi ◽  
M. Marcucci ◽  
G. Ciardelli
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Membrane Separation ◽  
Waste Water Treatment ◽  
Separation Processes ◽  
Textile Waste ◽  
Textile Waste Water

scholarly journals Graphene Membranes: From Reverse Osmosis to Gas Separation

2021 ◽  
Vol 8 (2) ◽  
pp. 1-27
Author(s):  
de Souza Figueiredo Katia Cecilia ◽  
de Jesus Barcelos Gustavo Feliciano ◽  
Ferlauto André Santarosa
Keyword(s):  
Reverse Osmosis ◽  
Membrane Separation ◽  
Skin Layer ◽  
Polymeric Membranes ◽  
Water Desalination ◽  
Innovative Technology ◽  
Separation Processes ◽  
Carbon Dioxide Separation ◽  
Current State ◽  
Graphene Membranes

Graphene membrane is a promising technology to help both carbon dioxide separation from flue gas and water desalination. This work reported the importance of membrane separation processes, the evolution of polymeric membranes before the discovery of graphene and how this material fits into this scenario. In addition, reverse osmosis and gas separations have been discussed as promising methods to reduce the occurrence of freshwater scarcity events and slow global warming. For all these separation techniques, the current state of graphene membranes technology and what advances might be brought by such one atom thick skin layer were presented, as well as the results of theoretical and experimental research. Finally, the challenges that still need to be overcome by this innovative technology as well as the perspectives were shown.

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.

scholarly journals Effect of Pre-Oxidation on Coagulation/Ceramic Membrane Treatment of Yangtze River Water

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 369
Author(s):  
Shengji Xia ◽  
Xinran Zhang ◽  
Yuanchen Zhao ◽  
Fibor J. Tan ◽  
Pan Li ◽  
...  
Keyword(s):  
Water Treatment ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Ceramic Membrane ◽  
Membrane Separation ◽  
Membrane System ◽  
Coagulation System ◽  
Fouling Control ◽  
Filtration System ◽  
Membrane Treatment

The membrane separation process is being widely used in water treatment. It is very important to control membrane fouling in the process of water treatment. This study was conducted to evaluate the efficiency of a pre-oxidation-coagulation flat ceramic membrane filtration process using different oxidant types and dosages in water treatment and membrane fouling control. The results showed that under suitable concentration conditions, the effect on membrane fouling control of a NaClO pre-oxidation combined with a coagulation/ceramic membrane system was better than that of an O3 system. The oxidation process changed the structure of pollutants, reduced the pollution load and enhanced the coagulation process in a pre-oxidation-coagulation system as well. The influence of the oxidant on the filtration system was related to its oxidizability and other characteristics. NaClO and O3 performed more efficiently than KMnO4. NaClO was more conducive to the removal of DOC, and O3 was more conducive to the removal of UV254.

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