scholarly journals Surface Design of Liquid Separation Membrane through Graft Polymerization: A State of the Art Review

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 832
Author(s):  
Deepa Suresh ◽  
Pei Sean Goh ◽  
Ahmad Fauzi Ismail ◽  
Nidal Hilal
Keyword(s):  
Surface Modification ◽  
Surface Properties ◽  
Graft Polymerization ◽  
Membrane Surface ◽  
Operating Conditions ◽  
Liquid Separation ◽  
Surface Design ◽  
Separation Membranes ◽  
Modification Technique ◽  
Grafting From

Surface modification of membranes is an effective approach for imparting unique characteristics and additional functionalities to the membranes. Chemical grafting is a commonly used membrane modification technique due to its versatility in tailoring and optimizing the membrane surface with desired functionalities. Various types of polymers can be precisely grafted onto the membrane surface and the operating conditions of grafting can be tailored to further fine-tune the membrane surface properties. This review focuses on the recent strategies in improving the surface design of liquid separation membranes through grafting-from technique, also known as graft polymerization, to improve membrane performance in wastewater treatment and desalination applications. An overview on membrane technology processes such as pressure-driven and osmotically driven membrane processes are first briefly presented. Grafting-from surface chemical modification approaches including chemical initiated, plasma initiated and UV initiated approaches are discussed in terms of their features, advantages and limitations. The innovations in membrane surface modification techniques based on grafting-from techniques are comprehensively reviewed followed by some highlights on the current challenges in this field. It is concluded that grafting-from is a versatile and effective technique to introduce various functional groups to enhance the surface properties and separation performances of liquid separation membranes.

scholarly journals Various Impregnation Methods Used for the Surface Modification of the Adsorbent: A Review

2018 ◽  
Vol 7 (4.7) ◽  
pp. 330 ◽  
Author(s):  
C. R. Girish ◽  
. .
Keyword(s):  
Surface Modification ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Surface Properties ◽  
Chemical Treatment ◽  
Water Contamination ◽  
Recent Time ◽  
Operating Conditions ◽  
Physical Chemical

The water contamination is an important crisis which is to be addressed in the recent time. The pollutants present in wastewater are treated by adsorption using activated carbon, which is considered as one of the effective method. The adsorbent has to be modified to improve the adsorption capacity and the surface properties. Various methods such as physical, chemical treatment, impregnation and functionalization techniques are available. Impregnation is one of the effective method carried out for surface modification and to increase the adsorption capacity. Therefore, current study investigates the different impregnation methods used for the surface modification of the adsorbent. It also reviews the various precursors used for adsorbent preparation, the impregnating agent, the operating conditions and the adsorption capacity of the adsorbent.  

scholarly journals Modulatory Role of Silver Nanoparticles and Mesenchymal Stem Cell–Derived Exosome-Modified Barrier Membrane on Macrophages and Osteogenesis

2021 ◽  
Vol 9 ◽  
Author(s):  
Haiping Lu ◽  
Yi Zhang ◽  
Shan Xiong ◽  
Yinghong Zhou ◽  
Lan Xiao ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Surface Modification ◽  
Ag Nanoparticles ◽  
Biological Activities ◽  
Membrane Surface ◽  
Microscopy Study ◽  
Barrier Membrane ◽  
Modification Technique ◽  
The Impact ◽  
Hybrid Scaffolds

Background: As a wound dressing and barrier membrane, surface modification of polycaprolactone (PCL) is needed in order to achieve better biological activities. Exosomes derived from mesenchymal stem cells (MSCs) hold significant tissue regeneration promise. Silver nanoparticles (Ag) have been suggested as the surface modification technique for various medical devices.Materials and Methods: Ag and human bone marrow MSC (hBMSC)-derived exosomes (MSCs-exo) were used to modify the PCL scaffold. The impact of different scaffolds on immune cells and MSC proliferation and differentiation was further evaluated.Results: MSCs-exo exhibited cup-shaped morphology with a diameter around 100 nm. MSCs-exo were enriched with exosome marker CD81 and showed good internalization into recipient cells. 200 ng/ml Ag nanoparticles and MSCs-exo were further used to modify the PCL scaffold. The internalization study further indicated a similar releasing pattern of exosomes from Ag/MSCs-exo hybrid scaffolds into RAW264.7 and hBMSCs at 12 and 24 h, respectively. Macrophages play an important role during different stages of bone regeneration. The MTT and confocal microscopy study demonstrated no significant toxicity of exosome and/or Ag hybrid scaffolds for macrophages and MSCs. Inflammatory macrophages were further used to mimic the inflammatory environment. A mixed population of elongated and round morphology was noted in the exosome and Ag hybrid group, in which the proinflammatory genes and secretion of IL-6 and TNF-α were significantly reduced. In addition, the exosome and Ag hybrid scaffolds could significantly boost the osteogenic differentiation of hBMSCs.Discussion: This study highlights the possibility of using Ag nanoparticles and MSCs-exo to modify the PCL scaffold, thus providing new insight into the development of the novel immunomodulatory biomembrane.

scholarly journals A Brief Review on the Evolution of Metallic Dental Implants: History, Design, and Application

2021 ◽  
Vol 8 ◽  
Author(s):  
Sumanth Ratna Kandavalli ◽  
Qingge Wang ◽  
Mahmoud Ebrahimi ◽  
Ceren Gode ◽  
Faramarz Djavanroodi ◽  
...  
Keyword(s):  
Surface Modification ◽  
Dental Implants ◽  
Dental Implant ◽  
Bacterial Attachment ◽  
Medical Implants ◽  
Surface Design ◽  
Design Procedures ◽  
Different Types ◽  
Modification Technique ◽  
Medical Materials

In recent years, significant advances in the field of medical materials have begun to emerge, especially in nanotechnology. The modern area of nanostructured implants possesses wide applications in various medical implants including their dental use. Nano-surface functions present substantial resolutions to medical obstacles through improved biomaterial proficiency, innovative dental-implant designs, and surface design procedures, such as nanoscale adhesive surfaces, bio-chemical anodization, and surface modification technique. This work covers dental implant history, nanotechnological advances, and its development that includes a description, basic properties, and the related results of composites and surface morphology, and the different types of nanomaterials used in dental implants. Significant attempts have been made over the last few decades to strengthen osteointegration and prevent bacterial attachment to the implant surfaces. The micro and nano-topography of the hierarchical surface orchestrate the biological reactions of implants and may solve the problems associated with implant-tissue issues. This research investigates the implant articles from 1964 to 2021, which offers a brief description of the nanostructured biomaterials to enhance dental implants’ performance and may open new frontiers in the advancement of implant technology.

scholarly journals Tanning Wastewater Treatment by Ultrafiltration: Process Efficiency and Fouling Behavior

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 461
Author(s):  
Fu Yang ◽  
Zhengkun Huang ◽  
Jun Huang ◽  
Chongde Wu ◽  
Rongqing Zhou ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Shear Rate ◽  
Membrane Surface ◽  
Filtration Efficiency ◽  
Operating Conditions ◽  
Process Efficiency ◽  
Transmembrane Pressure ◽  
Leather Industry ◽  
Pore Blocking ◽  
The Impact

Ultrafiltration is a promising, environment-friendly alternative to the current physicochemical-based tannery wastewater treatment. In this work, ultrafiltration was employed to treat the tanning wastewater as an upstream process of the Zero Liquid Discharge (ZLD) system in the leather industry. The filtration efficiency and fouling behaviors were analyzed to assess the impact of membrane material and operating conditions (shear rate on the membrane surface and transmembrane pressure). The models of resistance-in-series, fouling propensity, and pore blocking were used to provide a comprehensive analysis of such a process. The results show that the process efficiency is strongly dependent on the operating conditions, while the membranes of either PES or PVDF showed similar filtration performance and fouling behavior. Reversible resistance was the main obstacle for such process. Cake formation was the main pore blocking mechanism during such process, which was independent on the operating conditions and membrane materials. The increase in shear rate significantly increased the steady-state permeation flux, thus, the filtration efficiency was improved, which resulted from both the reduction in reversible resistance and the slow-down of fouling layer accumulate rate. This is the first time that the fouling behaviors of tanning wastewater ultrafiltration were comprehensively evaluated, thus providing crucial guidance for further scientific investigation and industrial application.

scholarly journals Rapid Surface Modification of Ultrafiltration Membranes for Enhanced Antifouling Properties

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 401
Author(s):  
Noresah Said ◽  
Ying Siew Khoo ◽  
Woei Jye Lau ◽  
Mehmet Gürsoy ◽  
Mustafa Karaman ◽  
...  
Keyword(s):  
Surface Modification ◽  
Deposition Time ◽  
Plasma Deposition ◽  
Membrane Surface ◽  
Pure Water ◽  
Plasma Modification ◽  
Surface Hydrophilicity ◽  
Water Cleaning ◽  
Modification Method ◽  
Modified Membrane

In this work, several ultrafiltration (UF) membranes with enhanced antifouling properties were fabricated using a rapid and green surface modification method that was based on the plasma-enhanced chemical vapor deposition (PECVD). Two types of hydrophilic monomers—acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) were, respectively, deposited on the surface of a commercial UF membrane and the effects of plasma deposition time (i.e., 15 s, 30 s, 60 s, and 90 s) on the surface properties of the membrane were investigated. The modified membranes were then subjected to filtration using 2000 mg/L pepsin and bovine serum albumin (BSA) solutions as feed. Microscopic and spectroscopic analyses confirmed the successful deposition of AA and HEMA on the membrane surface and the decrease in water contact angle with increasing plasma deposition time strongly indicated the increase in surface hydrophilicity due to the considerable enrichment of the hydrophilic segment of AA and HEMA on the membrane surface. However, a prolonged plasma deposition time (>15 s) should be avoided as it led to the formation of a thicker coating layer that significantly reduced the membrane pure water flux with no significant change in the solute rejection rate. Upon 15-s plasma deposition, the AA-modified membrane recorded the pepsin and BSA rejections of 83.9% and 97.5%, respectively, while the HEMA-modified membrane rejected at least 98.5% for both pepsin and BSA. Compared to the control membrane, the AA-modified and HEMA-modified membranes also showed a lower degree of flux decline and better flux recovery rate (>90%), suggesting that the membrane antifouling properties were improved and most of the fouling was reversible and could be removed via simple water cleaning process. We demonstrated in this work that the PECVD technique is a promising surface modification method that could be employed to rapidly improve membrane surface hydrophilicity (15 s) for the enhanced protein purification process without using any organic solvent during the plasma modification process.

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