scholarly journals Development of Multifunctional CoAl Based Layered Double Hydroxide Protective Film on Aluminum Alloy

2021 ◽  
Vol 2 (4) ◽  
pp. 708-720
Author(s):  
Muhammad Ahsan Iqbal ◽  
Humaira Asghar ◽  
Michele Fedel
Keyword(s):  
Contact Angle ◽  
Layered Double Hydroxide ◽  
Electrochemical Impedance ◽  
Protective Film ◽  
Structural Variations ◽  
Water Contact ◽  
Transfer Resistance ◽  
Surface Protection ◽  
Double Hydroxide

A protective CoAl-layered double hydroxide (LDH) thin film was developed directly on the aluminum substrate. Further, the low-surface-energy molecules (1H, 1H, 2H, 2H perfluorododecyl trichlorosilane) were incorporated inside the LDH network through an anion exchange mechanism to obtain a superhydrophobic CoAl-LDH surface. The developed films were characterized by scanning electron microscopy (SEM-EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR), and additional contact angle measurements were made to evaluate the superhydrophobicity of modified CoAl-LDHs against different solutions. The water contact angle (WCA) of the modified CoAl-LDH surface was observed to be about 153° and remained sufficiently stable after long-term immersion in NaCl solution. The effect of excessive ultrasonication on film structural variations and superhydrophobicity was also analyzed for outdoor applications. The high charge transfer resistance observed from the analysis of long-term electrochemical impedance spectroscopy (EIS) indicates the significant corrosion-resistance properties of the developed CoAl-LDHs. This research on protective CoAl-LDHs will bring insights into the understanding of new aspects of surface protection and implementation in many engineering applications.

scholarly journals Ce-Doped-MgAl Superhydrophobic Layered Double Hydroxide for Enhanced Corrosion Resistance Properties

Solids ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 76-86
Author(s):  
Muhammad Ahsan Iqbal ◽  
Humaira Asghar ◽  
Michele Fedel
Keyword(s):  
Thin Films ◽  
Contact Angle ◽  
Corrosion Resistance ◽  
Layered Double Hydroxide ◽  
Electrochemical Impedance ◽  
Morphological Characteristics ◽  
Aluminum Surface ◽  
Water Contact ◽  
Growth Method ◽  
Double Hydroxide

Double doped layered double hydroxide thin films were developed directly on the aluminum substrate in two steps: Initially cerium-based MgAl-layered double hydroxide (LDH) were synthesized directly on the anodic aluminum surface via the in situ growth method, and were then modified with the stearate anions through an ion-exchange mechanism to achieve compact multifunctional protective thin films. The structural and morphological characteristics of the developed LDH films were investigated, and the surface contact angle measurements (CA) and self-cleaning properties were analyzed. The obtained double doped LDH film displayed the superhydrophobic characteristic with a water contact angle of ~155°. Furthermore, the superhydrophobic behavior of LDH on exposure to UV radiation (λ = 310 nm) was examined to evaluate outdoor applications. Long-term Electrochemical Impedance Spectroscopy (EIS) analysis was performed to understand the corrosion resistance properties. The introduction of double doped LDHs demonstrates significantly higher corrosion resistance properties than only cerium-modified LDHs and has shown superior stability against 0.1 M NaCl solution.

Long-Term Stable Metal Organic Framework (MOF) Based Mixed Matrix Membranes for Ultrafiltration

2020 ◽  
Author(s):  
Muayad Al-shaeli ◽  
Stefan J. D. Smith ◽  
Shanxue Jiang ◽  
Huanting Wang ◽  
Kaisong Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Mixed Matrix Membranes ◽  
Recovery Ratio ◽  
Mixed Matrix ◽  
Water Contact ◽  
Membrane Performance ◽  
Metal Organic ◽  
Matrix Membranes

<p>In this study, novel <a>mixed matrix polyethersulfone (PES) membranes</a> were synthesized by using two different kinds of metal organic frameworks (MOFs), namely UiO-66 and UiO-66-NH<sub>2</sub>. The composite membranes were characterised by SEM, EDX, FTIR, PXRD, water contact angle, porosity, pore size, etc. Membrane performance was investigated by water permeation flux, flux recovery ratio, fouling resistance and anti-fouling performance. The stability test was also conducted for the prepared mixed matrix membranes. A higher reduction in the water contact angle was observed after adding both MOFs to the PES and sulfonated PES membranes compared to pristine PES membranes. An enhancement in membrane performance was observed by embedding the MOF into PES membrane matrix, which may be attributed to the super-hydrophilic porous structure of UiO-66-NH<sub>2</sub> nanoparticles and hydrophilic structure of UiO-66 nanoparticles that could accelerate the exchange rate between solvent and non-solvent during the phase inversion process. By adding the MOFs into PES matrix, the flux recovery ratio was increased greatly (more than 99% for most mixed matrix membranes). The mixed matrix membranes showed higher resistance to protein adsorption compared to pristine PES membranes. After immersing the membranes in water for 3 months, 6 months and 12 months, both MOFs were stable and retained their structure. This study indicates that UiO-66 and UiO-66-NH<sub>2</sub> are great candidates for designing long-term stable mixed matrix membranes with higher anti-fouling performance.</p>

scholarly journals Spilanthes acmella Leaves Extract for Corrosion Inhibition in Acid Medium

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 106
Author(s):  
Akbar Ali Samsath Begum ◽  
Raja Mohamed Abdul Vahith ◽  
Vijay Kotra ◽  
Mohammed Rafi Shaik ◽  
Abdelatty Abdelgawad ◽  
...  
Keyword(s):  
Mild Steel ◽  
Corrosion Inhibition ◽  
Active Sites ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Film Formation ◽  
Protective Film ◽  
Surface Protection ◽  
Tafel Polarization ◽  
Spilanthes Acmella

In the present study, the corrosion inhibition effect of Spilanthes acmella aqueous leaves extract (SA-LE) on mild steel was investigated in 1.0 M HCl solution at different temperature using weight loss, Tafel polarization, linear polarization resistance (LPR), and electrochemical impedance (EIS) measurements. Adsorption of inhibitor on the surface of the mild steel obeyed both Langmuir and Temkin adsorption isotherms. The thermodynamic and kinetic parameters were also calculated to determine the mechanism of corrosion inhibition. The inhibition efficiency was found to increase with an increase in the inhibitor concentration i.e., Spilanthes acmella aqueous leaves extract, however, the inhibition efficiency decreased with an increase in the temperature. The phytochemical constituents with functional groups including electronegative hetero atoms such as N, O, and S in the extract adsorbed on the metal surface are found responsible for the effective performance of the inhibitor, which was confirmed by Fourier-transform infrared spectroscopy (FT-IR) and ultraviolet–visible spectroscopic (UV-Vis) studies. Protective film formation against corrosion was confirmed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle studies. The result shows that the leaves extract acts as corrosion inhibitor and is able to promote surface protection by blocking active sites on the metal.

scholarly journals Corrosion Inhibitive Action and Adsorption Behaviour of Justicia Secunda Leaves Extract as an Eco‐Friendly Inhibitor for Aluminium in Acidic Media

2021 ◽  
Vol 11 (5) ◽  
pp. 13019-13030
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Weight Loss ◽  
Electrochemical Impedance ◽  
Physical Adsorption ◽  
Charge Transfer Resistance ◽  
Aluminum Surface ◽  
Protective Film ◽  
Transfer Resistance ◽  
Scanning Electron

The extract of Justicia secunda (JS) leaves was investigated as an eco‐friendly corrosion inhibitor of aluminum in 0.5 M HCl using weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and scanning electron microscopy (SEM) techniques. The inhibitor concentrations used ranged from 50 to 250 ppm at 30, 40, and 50oC. Results show that Justicia secunda acts as a good inhibitor for aluminum. Its efficiency increased with increasing inhibitor concentration but decreased with increasing temperature. Maximum inhibition efficiency as high as 94.3% was found at 30°C for 250 ppm of the inhibitor with the weight loss technique. Tafel polarization results show that the extract acts as a mixed-type inhibitor. The Nyquist plots indicated decreasing double-layer capacitance and increasing charge transfer resistance on increasing JS concentration. The inhibition action occurred through the physical adsorption of the extract on the aluminum surface. The adsorption process was found to follow Langmuir adsorption isotherm. The formation of a protective film on the metal surface was confirmed by scanning electron microscopy.

Synthesis of three-dimensional mesoporous Cu–Al layered double hydroxide/g-C3N4 nanocomposites on Ni-foam for enhanced supercapacitors with excellent long-term cycling stability

2018 ◽  
Vol 47 (13) ◽  
pp. 4455-4466 ◽  
Author(s):  
Surya Prasad Adhikari ◽  
Ganesh Prasad Awasthi ◽  
Kyung-Suk Kim ◽  
Chan Hee Park ◽  
Cheol Sang Kim
Keyword(s):  
Layered Double Hydroxide ◽  
Three Dimensional ◽  
Cycling Stability ◽  
Ni Foam ◽  
Step Process ◽  
Double Hydroxide

In this study, a novel composite of Cu–Al layered double hydroxide (LDH) nanosheets and g-C3N4-covered Ni-foam was fabricated via a simple and facile two-step process.

Long-Term Stable Metal Organic Framework (MOF) Based Mixed Matrix Membranes for Ultrafiltration

2020 ◽  
Author(s):  
Muayad Al-shaeli ◽  
Stefan J. D. Smith ◽  
Shanxue Jiang ◽  
Huanting Wang ◽  
Kaisong Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Mixed Matrix Membranes ◽  
Recovery Ratio ◽  
Mixed Matrix ◽  
Water Contact ◽  
Membrane Performance ◽  
Metal Organic ◽  
Matrix Membranes

<p>In this study, novel <a>mixed matrix polyethersulfone (PES) membranes</a> were synthesized by using two different kinds of metal organic frameworks (MOFs), namely UiO-66 and UiO-66-NH<sub>2</sub>. The composite membranes were characterised by SEM, EDX, FTIR, PXRD, water contact angle, porosity, pore size, etc. Membrane performance was investigated by water permeation flux, flux recovery ratio, fouling resistance and anti-fouling performance. The stability test was also conducted for the prepared mixed matrix membranes. A higher reduction in the water contact angle was observed after adding both MOFs to the PES and sulfonated PES membranes compared to pristine PES membranes. An enhancement in membrane performance was observed by embedding the MOF into PES membrane matrix, which may be attributed to the super-hydrophilic porous structure of UiO-66-NH<sub>2</sub> nanoparticles and hydrophilic structure of UiO-66 nanoparticles that could accelerate the exchange rate between solvent and non-solvent during the phase inversion process. By adding the MOFs into PES matrix, the flux recovery ratio was increased greatly (more than 99% for most mixed matrix membranes). The mixed matrix membranes showed higher resistance to protein adsorption compared to pristine PES membranes. After immersing the membranes in water for 3 months, 6 months and 12 months, both MOFs were stable and retained their structure. This study indicates that UiO-66 and UiO-66-NH<sub>2</sub> are great candidates for designing long-term stable mixed matrix membranes with higher anti-fouling performance.</p>

Enhanced Corrosion Resistance of Superhydrophobic Layered Double Hydroxide Films with Long-Term Stability on Al Substrate

2018 ◽  
Vol 10 (17) ◽  
pp. 15150-15162 ◽  
Author(s):  
Yanhui Cao ◽  
Dajiang Zheng ◽  
Xueliang Li ◽  
Jinyan Lin ◽  
Cheng Wang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Layered Double Hydroxide ◽  
Term Stability ◽  
Long Term Stability ◽  
Double Hydroxide

scholarly journals Adsorption and Corrosion Inhibition Effect ofN-(l-Morpholinobenzyl)urea onMild Steel in Acidic Medium

2011 ◽  
Vol 8 (2) ◽  
pp. 621-628 ◽  
Author(s):  
M. Anwar Sathiq ◽  
A. Jamal Abdul Nasser ◽  
P. Mohamed Sirajudeen
Keyword(s):  
Mild Steel ◽  
Corrosion Inhibition ◽  
Potentiodynamic Polarization ◽  
Steel Surface ◽  
Electrochemical Impedance ◽  
Effect Of Temperature ◽  
Protective Film ◽  
Acid Attack ◽  
Transfer Resistance ◽  
Mild Steel Surface

The influence ofN-(l-morpholinobenzyl)urea (MBU) on corrosion inhibition of mild steel in 1 M HCl was studied by weight loss, effect of temperature, potentiodynamic polarization and electrochemical impedance spectroscopy. The experimental results showed that the inhibition efficiency increases with increasing of MBU concentrations but decreases with increasing temperatures. The adsorption of MBU on the mild steel surface obeyed the Temkin’s adsorption isotherm. Potentiodynamic polarization curves showed that MBU acted as a cathodic inhibitor predominantly in hydrochloric acid. This was supported by the impedance measurements which showed a change in the charge transfer resistance and double layer capacitance indicating adsorption of MBU on the mild steel surface. Protective film formation against the acid attack is confirmed by SEM.

A Two-Step Method to Prepare Stable Superhydrophobic Surface on Steel Substrates

2012 ◽  
Vol 463-464 ◽  
pp. 349-353 ◽  
Author(s):  
Feng Guo ◽  
Xun Jia Su ◽  
Gen Liang Hou ◽  
Zhao Hui Liu ◽  
Hai Peng Jia
Keyword(s):  
Contact Angle ◽  
Superhydrophobic Surface ◽  
Low Cost ◽  
Superhydrophobic Surfaces ◽  
Step Method ◽  
Water Contact ◽  
Lotus Leaf ◽  
Nanoscale Particles ◽  
Steel Substrates

Superhydrophobic surfaces have been a hot topic during the last decade owing to their great potential in widely application. In this work, we report on a facile and low-cost two-step method to fabricate superhydrophobic surface on steel substrates. The as-obtained surface shows an interesting hierarchical structure composed of microscale flowerlike cluster and nanoscale particles, which is similar to that of a lotus leaf. After further modification with stearic acid, the resultant surface exhibits remarkable superhydrophobic properties. The water contact angle is as high as 155°. Moreover, the superhydrophobic properties are long-term stable.

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