Theoretical and experimental insights into the C-steel aqueous corrosion inhibition at elevated temperatures in 1.0M HCl via multi-carbonyl Gemini cationic surfactants

Despite corrosion being an inevitable process, researchers strive to control corrosion. In this study, our goal was to prepare two amido Gemini cationic surfactants, LAPG and MAPG, each with different alkyl chains and multiple carbonyl groups as rich electronic rich centers. We aimed to evaluate these surfactants as potential corrosion inhibitors for carbon steel (CS) in 1M HCl at temperatures of 25-55 ± 0.1°C. In theoretical investigations, DFT parameters and Mont Carlo simulation were run to predict the adsorption affinity and reactive sites of the LAPG and MAPG molecules. Their efficacy was investigated experimentally considering weight loss and electrochemical techniques. The Tafel polarization revealed that at 0.1mM of LAPG and MAPG, the corrosion current density (i corr) of CS was reduced to the lowest extent (75.56 and 53.82μAcm-2) compared to 529.3μAcm-2 in the absence of the inhibitors. EIS data suggests the enhancement of the thickness of the adsorbed layers of the studied compounds from the decrease of the double-layer capacitance C dl values. The Langmuir isotherm explained the adoption phenomena of these compounds at 25-55 ± 0.1°C. Activation and adsorption thermodynamic parameters predicted the chemisorption behavior of these molecules onto the steel surface. AFM and XPS tools confirm the CS surface protection due to these inhibitors' adsorbed layer. A parallel study showed the superiority of these corrosion inhibitors in HCl compared with those reported earlier, making these compounds highly promising corrosion inhibitors, especially in high-temperature acidic environments

Synthesis of Gemini cationic surfactants based on natural nicotinic acid and evaluation of their inhibition performance at C-steel/1 M HCl interface: Electrochemical and computational investigations

Herein, we prepare effective Gemini cationic surfactants (CSII, CSIV) and characterize them using FT-IR and 1HNMR spectroscopy. The adsorptive properties of CSII and CSIV at HCl/air and C-steel/HCl interfaces were examined with surface tension and electrochemical parameters, respectively. The critical micelle concentration (CMC) of the CSII and CSIV indicated their adsorption affinity at the HCl/air interface. Where, aliphatic chains increase surface coverage percentage and aid in surfactant adsorption. The electrochemical parameters of C-steel in 1 M HCl were studied using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) at different temperatures. The charge transfer resistance of the C-steel electrode was enhanced from 28.2 Ω.cm2 to 770.79 and 831.45 Ω.cm2 after adding 5 × 10−4 M of CSII and CSIV, respectively. Both CSII and CSIV act as mixed inhibitors with inhibition performance exceeding 97% due to their highly adsorption affinity. The chemical adsorption affinity of these compounds is suggested by the higher adsorption energy (∆G*ads) values (>−40 kJ mol−1) according to the Langmuir isotherm model. The theoretical calculations including DFT, and Monte Carlo simulation (MCs) provide insight into the relationship between corrosion inhibition and molecular structure, where the calculated parameters agree with the experimental results

Recent Advances in Aptamer Sensors

Recently, aptamers have attracted attention in the biosensing field as signal recognition elements because of their high binding affinity toward specific targets such as proteins, cells, small molecules, and even metal ions, antibodies for which are difficult to obtain. Aptamers are single oligonucleotides generated by in vitro selection mechanisms via the systematic evolution of ligand exponential enrichment (SELEX) process. In addition to their high binding affinity, aptamers can be easily functionalized and engineered, providing several signaling modes such as colorimetric, fluorometric, and electrochemical, in what are known as aptasensors. In this review, recent advances in aptasensors as powerful biosensor probes that could be used in different fields, including environmental monitoring, clinical diagnosis, and drug monitoring, are described. Advances in aptamer-based colorimetric, fluorometric, and electrochemical aptasensing with their advantages and disadvantages are summarized and critically discussed. Additionally, future prospects are pointed out to facilitate the development of aptasensor technology for different targets

Evaluation of N-(3-(dimethyl hexadecyl ammonio)propyl) palmitamide bromide as cationic surfactant corrosion inhibitor for API N80 steel in acidic environment

A new cationic surfactant named (N-(3-(dimethyl hexadecyl ammonio)propyl) palmitamide bromide has been evaluated as corrosion inhibitor for API N80 Steel Pipelines in 1M HCl solution. Four different techniques have been utilized for studying the corrosion behavior of the synthesized cationic amphipathic corrosion inhibitor. The prepared corrosion inhibitor was evaluated at five different temperatures 25, 30, 40, 50 and 60 °C, using weight loss technique. The three other techniques which are potentiodynamic polarization, Electrochemical impedance (EIS) and Electrochemical frequency modulation (EFM) were used for evaluation at room temperature (25 °C ± 1). The results outlined that the synthesized DMHPP amphipathic corrosion inhibitor was good inhibitor and their inhibition efficiencies were directly proportional with both the inhibitor concentration and temperature. Polarization curve revealed that the studied inhibitor act as a mixed-type of inhibitor. The adsorption of the used inhibitor led to a reduction in the double layer capacitance and an increase in the charge transfer resistance. The adsorption behavior of the amphipathic inhibitor obey Langmuir adsorption model. The change in free energy of adsorption of the synthesized inhibitor range from −40.5 to −45.5 kJ mol−1 as an indication for chemisorption process between inhibitor and steel. A clear correlation was found between corrosion inhibition efficiency and theoretical parameters obtained using density functional theory (DFT). Keywords: Steel, Cationic surfactant, Potentiodynamic polarization, EIS, EFM, Quantum chemical calculatio

Cationic surfactant based on alignate as green corrosion inhibitors for the mild steel in 1.0 M HCl

Three cationic surfactants based on alginic acid were laboratory prepared. These compounds were evaluated as corrosion inhibitors utilizing three techniques, namely; weight loss, polarization and electrochemical impedance spectroscopy. The corrosive medium was 1.0 M HCl. The corrosion rate of mild steel in 1.0 M HCl at four different temperatures 25, 40, 55 and 70 °C was investigated gravimetrically. The corrosion rate of mild steel was confirmed electrochemically at 25 °C. It was found that the corrosion inhibition efficiency directly proportionally with the hydrophobic chain length of synthesized inhibitors and also with the plethora of concentration. The inhibition efficiency exhibit a positive trend with raising the solution temperatures as indication for chemisorption. The potentiostatic polarization study revealed that the tested green cationic surfactants act as mixed type inhibitors with predominant control of cathodic reaction. The decreasing in the double layer capacitance obtained from electrochemical impedance measurements refer to increasing the thickness of the formed double layer. The apparent activation energy of the inhibited solution was found to be lower than uninhibited solution as an indication for chemical adsorption

Evaluation of a novel cationic surfactant based on 2-(2 (dimethylamino)ethoxy)ethanol as a corrosion inhibitor for carbon steel 1018 in 1.0 M HCl solution

Corrosion inhibition of a novel cationic surfactant namely, N-(2-(2-hydroxyethoxy)ethyl)-N,N-dimethyldodecan-1-aminium bromide (HEDDB) was evaluated as a corrosion inhibitor for carbon steel in 1.0 M HCl by electrochemical frequency modulation (EFM), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and weight loss measurements. Results of Tafel polarization exhibit that the synthesized surfactant HEDDB behaves as mixed-type inhibitor. The effectiveness of temperature on the corrosion rate which evaluated by chemical technique (weight loss) was investigated and assessed. Langmuir’s adsorption isotherm was the preferable fitted isotherm. The results of weight loss clarified that the efficiency of the synthesized surfactant increases with raising both the concentration of the surfactant and the temperature. HEDDB effectiveness on the morphology of metal surface was monitored by Atomic Force Microscopy (AFM) and Scanning Electron Microscope (SEM) techniques. Quantum chemical technique has been employed to discuss the inhibition efficiency by effectiveness of molecular structure of the synthesized inhibitor. The various techniques which used in this research have inhibition efficiency (IE) with the same direction. Keywords: Carbon steel, Cationic surfactant, HCl, HEDDB, Potentiodynamic polarization, EIS, EFM, SEM, AF

Correction to “Dual-Surfactant-Capped Ag Nanoparticles as a Highly Selective and Sensitive Colorimetric Sensor for Citrate Detection”

Correction to “Dual-Surfactant-Capped Ag Nanoparticles as a Highly Selective and Sensitive Colorimetric Sensor for Citrate Detection

Fabrication of TiO2/NiO p-n Nanocomposite for Enhancement Dye Photodegradation under Solar Radiation

A p-n nanocomposite based on TiO2 nanotubes (NTs) and NiO nanoparticles (NPs) was designed and optimized in this study to improve the photocatalytic performance of methylene blue (MB). The hydrothermal technique has been used to produce TiO2/NiO nanocomposites with different NiO NPs weight ratios; 1TiO2:1NiO, 1TiO2:2NiO, and 1TiO2:3NiO. The crystal phase, chemical composition, optical properties, and morphology of TiO2/NiO were explored by various techniques. TiO2 NTs have a monoclinic structure, while NiO NPs have a cubic structure, according to the structural study. The bandgap of TiO2 NTs was reduced from 3.54 eV to 2.69 eV after controlling the NiO NPs weight ratio. The TiO2/2NiO nanocomposite showed the best photodegradation efficiency. Within 45 min of solar light irradiation, the efficiency of MB dye degradation using TiO2/2NiO hits 99.5% versus 73% using pure TiO2 NTs. Furthermore, the catalytic photodegradation efficiency did not deteriorate significantly even after five reusability cycles, intimating the high stability of the TiO2/2NiO nanocomposite. This suggests that the loading of NiO NPs into TiO2 NTs lowers the recombination of photo-produced electron/hole pairs and enlarged solar spectral response range, which results in improved photocatalytic activity. The mechanism of charge transfer in the TiO2/NiO and kinetic models were discussed for the photodegradation of MB