scholarly journals Recent Progress on Tailoring and Modification of Membranes for Membrane Distillation: A Review

2021 ◽  
Vol 25 (3) ◽  
pp. 93-117
Author(s):  
Nur Hashimah Alias ◽  
Nur Fazira Sufianasuri
Keyword(s):  
High Efficiency ◽  
Saline Water ◽  
Morphological Structure ◽  
Membrane Distillation ◽  
Future Research ◽  
Separation And Purification ◽  
Hydrophobic Membrane ◽  
Comprehensive Overview ◽  
Water Contact ◽  
Hydrophobic Membranes

Membrane distillation (MD) has gained the interest of many researchers since it is a promising method for the separation and purification process. Membrane distillation (MD) is a non-isothermal separation process in which differential vapor pressure between porous hydrophobic membrane surfaces acts as a driving factor. A hydrophobic membrane is used in the application of MD, which permits only the passage of vapor produced on the feed side through its pores to the permeate side. One of the most significant obstacles to the commercialisation of the MD method is a lack of appropriate membranes for the process. On the other hand, conventional hydrophobic membranes are subjected to rapid wetting and severe fouling, mainly when low surface tension compounds are present in saline water, resulting in decreased MD performance. In recent decades, MD membranes have received exceptional scientific interest, with substantial progress being made in the design and production of MD membranes appropriate for use in many applications. This review gives a comprehensive overview of recent research developments in the tailoring morphological structure of hydrophobic membranes, emphasising advancements in the fabrication and modification of membranes towards exhibiting high efficiency in the MD process. In addition, the critical morphology characteristics, mainly surface roughness, wettability, and water contact angle, are analysed. Finally, the challenges faced and future research direction is highlighted.  

scholarly journals A Review of Membrane Distillation Process: Before, During and After Testing

2019 ◽  
Vol 6 (1) ◽  
pp. 62-81
Author(s):  
N.A.S. Muhamad ◽  
Nadzirah Mohd Mokhtar ◽  
R. Naim ◽  
W.J. Lau ◽  
A.F. Ismail
Keyword(s):  
Membrane Fouling ◽  
Treatment Process ◽  
Membrane Distillation ◽  
Separation And Purification ◽  
Hydrophobic Membrane ◽  
Major Drawback ◽  
Membrane Performance ◽  
Membrane Surfaces ◽  
Thermally Driven ◽  
Pass Through

Membrane Distillation (MD) is a promising technology for separation and purification processes. It is a thermally-driven separation process which allow only vapour molecules are to pass through a porous hydrophobic membrane. MD separation is driven by the vapour pressure difference existing between the porous hydrophobic membrane surfaces unlike normal membrane processes which operate on temperature difference. This paper focus on the expectation of MD treatment process primarily for the readers who have no idea about this membrane process A brief overview is given of MD before treatment process which includes membrane materials, membrane preparation techniques, membrane characteristics, module and configuration. Membrane performance during treatment process will be highlighted. Membrane fouling which is one of the major drawback of MD will be also discussed.

scholarly journals A contact angle study of different greywater sources with hydrophobic membranes

2020 ◽  
Vol 55 (3) ◽  
pp. 310-326
Author(s):  
Mohammad Ramezanianpour ◽  
Muttucumaru Sivakumar ◽  
Natalie Osborn ◽  
Ying Zhang ◽  
Hakim Kawa
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Pure Water ◽  
Membrane Distillation ◽  
Hydrophobic Membrane ◽  
Flat Sheet ◽  
Hydrophobic Membranes ◽  
Different Types ◽  
The Impact ◽  
Surface Tension Forces

Abstract The wetting phenomenon is a major problem in the membrane distillation (MD) process, and it is the main reason that limits MD being used in wastewater reclamation. Active surfactant in the detergents reduces the contact angle between the liquid and the hydrophobic membrane surface, which could result in wetting. Extensive laboratory research was conducted using commercial hydrophobic flat-sheet membranes to identify the impact of anionic surfactants and surface tension forces on these membranes. The aim of this paper is to find a suitable membrane for pure water production from greywater using MD, as well as to provide a relationship between surfactant concentration and the contact angle for different types of membrane. The absorbance of each sample was measured by a spectrophotometer prior to the contact angle test on four different types of hydrophobic membranes. It was concluded that the polypropylene membrane would be unsuitable for the treatment of greywater directly due to the loss of surface tension forces upon the addition of an anionic surfactant. However, the polytetrafluoroethylene membrane could be effective in this process while the concentration of surfactant in the feed source is kept constant. The results from the experimental tests proposed a relationship between the contact angle of a water droplet on the surface of a flat-sheet membrane and the concentration of surfactant in the solution.

scholarly journals Surface Oxidation of Ethylenechlorotrifluoroethylene (ECTFE) Membrane for the Treatment of Real Produced Water by Membrane Distillation

2018 ◽  
Vol 15 (8) ◽  
pp. 1561 ◽  
Author(s):  
Zahra Anari ◽  
Arijit Sengupta ◽  
Sumith Wickramasinghe
Keyword(s):  
Produced Water ◽  
Membrane Surface ◽  
Surface Oxidation ◽  
Membrane Distillation ◽  
Hydrophobic Membrane ◽  
Water Contact ◽  
Potential Measurement ◽  
Salt Deposition ◽  
Organic Fouling ◽  
Simple Surface

Modification of ethyleneechlorotrifluoroethylene (ECTFE) membranes by simple surface oxidation was reported in the present investigation in order to induce thin hydrophilic layer on hydrophobic membrane surface for the treatment of real produced water (PW). FTIR spectra indicates the appearance of hydrophilic functional groups (–OH and –COOH) on the membrane surface due to modification, while water contact angle, zeta potential measurement, EDX, XPS analysis confirmed the presence of O functionalized hydrophilic groups on the surface. The effect of modification temperature and the time of surface oxidation on the performance of the resulting membranes were studied systematically, which revealed that induction of optimized hydrophilicity can successfully reduce the organic fouling. However, too much hydrophilic surface induces polar/electrostatic interaction resulting salt deposition on membrane surface. A simple on site cleaning procedure was demonstrated to be successful for the treatment PW for at least three consecutive cycles of membrane distillation (MD).

scholarly journals Carnauba Wax/Halloysite Nanotube with Improved Anti-Wetting and Permeability of Hydrophobic PVDF Membrane via DCMD

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 228
Author(s):  
Wan Aisyah Fadilah Wae AbdulKadir ◽  
Abdul Latif Ahmad ◽  
Ooi Boon Seng
Keyword(s):  
Vinylidene Fluoride ◽  
Metal Oxide Nanoparticles ◽  
Membrane Distillation ◽  
Attenuated Total Reflection ◽  
Hydrophobic Membrane ◽  
Water Contact ◽  
Halloysite Nanotube ◽  
Pvdf Membrane ◽  
Carnauba Wax ◽  
Wetting Properties

The hydrophobic membranes have been widely explored to meet the membrane characteristics for the membrane distillation (MD) process. Inorganic metal oxide nanoparticles have been used to improve the membrane hydrophobicity, but limited studies have used nano clay particles. This study introduces halloysite nanotube (HNT) as an alternative material to synthesis a hydrophobic poly(vinylidene fluoride) (PVDF)-HNT membrane. The PVDF membranes were fabricated using functionalized HNTs (e.g., carnauba wax and 1H,1H,2H,2H-perfluorooctyl-trichlorosilane (FOTS)). The results were determined by Fourier transform infrared-attenuated total reflection, scanning electron microscope, goniometer and porometer to determine the desired hydrophobic membrane for direct contact membrane distillation (DCMD). The addition of FOTS-HNT (fs-HNT) and carnauba wax-HNT (fw-HNT) in the PVDF membrane enhanced the water contact angle (CA) to 127° and 137°, respectively. The presence of fw-HNT in the PVDF membrane exhibited higher liquid entry pressure (LEP) (2.64 bar) compared to fs-HNT in the membrane matrix (1.44 bar). The PVDF/fw-HNT membrane (Pfw-HNT) obtained the highest flux of 7.24 L/m2h with 99.9% salt removal. A stable permeability in the Pfw-HNT membrane was obtained throughout 16 h of DCMD. The incorporation of fw-HNT in the PVDF membrane had improved the anti-wetting properties and the membrane performance with the anti-fouling effect.

Metabolism and Distribution of Novel Tumor Targeting Drugs In Vivo

2020 ◽  
Vol 21 (13) ◽  
pp. 996-1008
Author(s):  
Mengli Wang ◽  
Qiuzheng Du ◽  
Lihua Zuo ◽  
Peng Xue ◽  
Chao Lan ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Small Molecule ◽  
High Efficiency ◽  
Tumor Therapy ◽  
Research Progress ◽  
Future Research ◽  
Pharmacokinetic Parameters ◽  
Molecular Characteristics ◽  
Targeted Drugs

Background: As a new tumor therapy, targeted therapy is becoming a hot topic due to its high efficiency and low toxicity. Drug effects of targeted tumor drugs are closely related to pharmacokinetics, so it is important to understand their distribution and metabolism in vivo. Methods: A systematic review of the literature on the metabolism and distribution of targeted drugs over the past 20 years was conducted, and the pharmacokinetic parameters of approved targeted drugs were summarized in combination with the FDA's drug instructions. Targeting drugs are divided into two categories: small molecule inhibitors and monoclonal antibodies. Novel targeting drugs and their mechanisms of action, which have been developed in recent years, are summarized. The distribution and metabolic processes of each drug in the human body are reviewed. Results: In this review, we found that the distribution and metabolism of small molecule kinase inhibitors (TKI) and monoclonal antibodies (mAb) showed different characteristics based on the differences of action mechanism and molecular characteristics. TKI absorbed rapidly (Tmax ≈ 1-4 h) and distributed in large amounts (Vd > 100 L). It was mainly oxidized and reduced by cytochrome P450 CYP3A4. However, due to the large molecular diameter, mAb was distributed to tissues slowly, and the volume of distribution was usually very low (Vd < 10 L). It was mainly hydrolyzed and metabolized into peptides and amino acids by protease hydrolysis. In addition, some of the latest drugs are still in clinical trials, and the in vivo process still needs further study. Conclusion: According to the summary of the research progress of the existing targeting drugs, it is found that they have high specificity, but there are still deficiencies in drug resistance and safety. Therefore, the development of safer and more effective targeted drugs is the future research direction. Meanwhile, this study also provides a theoretical basis for clinical accurate drug delivery.

scholarly journals Organizational Commitment and Lean Sustainability: Literature Review and Directions for Future Research

2021 ◽  
Vol 13 (6) ◽  
pp. 3357 ◽  
Author(s):  
Amal Benkarim ◽  
Daniel Imbeau
Keyword(s):  
Organizational Commitment ◽  
Literature Review ◽  
Lean Manufacturing ◽  
Affective Commitment ◽  
Management Practices ◽  
Employee Commitment ◽  
Future Research ◽  
Comprehensive Overview ◽  
Narrative Literature Review ◽  
Key Aspects

The vast majority of works published on Lean focus on the evaluation of tools and/or the strategies needed for its implementation. Although many authors highlight the degree of employee commitment as one of the key aspects of Lean, what has gone largely unnoticed in the literature, is that few studies have examined in-depth the concept of organizational commitment in connection with Lean. With this narrative literature review article, our main objective is (1) to identify and analyze an extensive body of literature that addresses the Lean Manufacturing approach and how it relates to employee commitment, emphasizing affective commitment as the main type of organizational commitment positively associated with Lean, and (2) to highlight the management practices required to encourage this kind of commitment and promote the success and sustainability of Lean. This paper aims to provide a comprehensive overview that can help researchers and practitioners interested in Lean better understand the importance of employee commitment in this type of approach, and as well, to identify related research questions.

scholarly journals Research on the Operating Characteristics of Hydraulic Free-Piston Engines: A Systematic Review and Meta-Analysis

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3530
Author(s):  
Fukang Ma ◽  
Shuanlu Zhang ◽  
Zhenfeng Zhao ◽  
Yifang Wang
Keyword(s):  
Systematic Review ◽  
High Efficiency ◽  
Meta Analysis ◽  
Combustion Process ◽  
Research Progress ◽  
Future Research ◽  
Operating Characteristics ◽  
Piston Engine ◽  
Free Piston ◽  
Free Piston Engine

The hydraulic free-piston engine (HFPE) is a kind of hybrid-powered machine which combines the reciprocating piston-type internal combustion engine and the plunger pump as a whole. In recent years, the HFPE has been investigated by a number of research groups worldwide due to its potential advantages of high efficiency, energy savings, reduced emissions and multi-fuel operation. Therefore, our study aimed to assess the operating characteristics, core questions and research progress of HFPEs via a systematic review and meta-analysis. We included operational control, starting characteristics, misfire characteristics, in-cylinder working processes and operating stability. We conducted the literature search using electronic databases. The research on HFPEs has mainly concentrated on four kinds of free-piston engine, according to piston arrangement form: single piston, dual pistons, opposed pistons and four-cylinder complex configuration. HFPE research in China is mainly conducted in Zhejiang University, Tianjin University, Jilin University and the Beijing Institute of Technology. In addition, in China, research has mainly focused on the in-cylinder combustion process while a piston is free by considering in-cylinder combustion machinery and piston dynamics. Regarding future research, it is very important that we solve the instabilities brought about by chance fluctuations in the combustion process, which will involve the hydraulic system’s efficiency, the cyclical variation, the method of predicting instability and the recovery after instability.

scholarly journals Review on the Use of Artificial Intelligence to Predict Fire Performance of Construction Materials and Their Flame Retardancy

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1022
Author(s):  
Hoang T. Nguyen ◽  
Kate T. Q. Nguyen ◽  
Tu C. Le ◽  
Guomin Zhang
Keyword(s):  
Artificial Intelligence ◽  
Flame Retardancy ◽  
Material Science ◽  
Construction Materials ◽  
Engineering Problem ◽  
Future Research ◽  
Fire Performance ◽  
Structural Components ◽  
Comprehensive Overview ◽  
Fire Engineering

The evaluation and interpretation of the behavior of construction materials under fire conditions have been complicated. Over the last few years, artificial intelligence (AI) has emerged as a reliable method to tackle this engineering problem. This review summarizes existing studies that applied AI to predict the fire performance of different construction materials (e.g., concrete, steel, timber, and composites). The prediction of the flame retardancy of some structural components such as beams, columns, slabs, and connections by utilizing AI-based models is also discussed. The end of this review offers insights on the advantages, existing challenges, and recommendations for the development of AI techniques used to evaluate the fire performance of construction materials and their flame retardancy. This review offers a comprehensive overview to researchers in the fields of fire engineering and material science, and it encourages them to explore and consider the use of AI in future research projects.

scholarly journals Metal–Organic Framework-Based Solid Acid Materials for Biomass Upgrade

2021 ◽  
Author(s):  
Yutian Qin ◽  
Jun Guo ◽  
Meiting Zhao
Keyword(s):  
High Efficiency ◽  
Solid Acid ◽  
Metal Organic Framework ◽  
Acid Sites ◽  
Solid Acid Catalysts ◽  
Future Research ◽  
Acid Catalysts ◽  
Metal Organic ◽  
Biomass Transformation ◽  
Organic Framework

AbstractBiomass is a green and producible source of energy and chemicals. Hence, developing high-efficiency catalysts for biomass utilization and transformation is urgently demanded. Metal–organic framework (MOF)-based solid acid materials have been considered as promising catalysts in biomass transformation. In this review, we first introduce the genre of Lewis acid and Brønsted acid sites commonly generated in MOFs or MOF-based composites. Then, the methods for the generation and adjustment of corresponding acid sites are overviewed. Next, the catalytic applications of MOF-based solid acid materials in various biomass transformation reactions are summarized and discussed. Furthermore, based on our personal insights, the challenges and outlook on the future development of MOF-based solid acid catalysts are provided. We hope that this review will provide an instructive roadmap for future research on MOFs and MOF-based composites for biomass transformation.

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