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Austenitic stainless steels (ASS) are extensively employed in various sectors such as nuclear, power, petrochemical, oil and gas because of their excellent structural strength and resistance to corrosion. SS304 and SS316 are the predominant choices for piping, pressure vessels, heat exchangers, nuclear reactor core components and support structures, but they are susceptible to stress corrosion cracking (SCC) in chloride-rich environments. Over the course of several decades, extensive research efforts have been directed towards evaluating SCC using diverse methodologies and models, albeit some uncertainties persist regarding the precise progression of cracks. This review paper focuses on the application of Acoustic Emission Technique (AET) for assessing SCC damage mechanism by monitoring the dynamic acoustic emissions or inelastic stress waves generated during the initiation and propagation of cracks. AET serves as a valuable non-destructive technique (NDT) for in-service evaluation of the structural integrity within operational conditions and early detection of critical flaws. By leveraging the time domain and time-frequency domain techniques, various Acoustic Emission (AE) parameters can be characterized and correlated with the multi-stage crack damage phenomena. Further theories of the SCC mechanisms are elucidated, with a focus on both the dissolution-based and cleavage-based damage models. Through the comprehensive insights provided here, this review stands to contribute to an enhanced understanding of SCC damage in stainless steels and the potential AET application in nuclear industry.

This study addresses the challenge of preferential weld corrosion in ASTM A333 carbon steel piping, investigating the intricate interplay of various factors. The welding process induces microstructural alterations, making affected areas more prone to corrosion, resulting in Preferential Weld Corrosion (PWC). While the addition of 1 % nickel filler shifts the galvanic potential of Weld Metal (WM), its impact on PWC is marginal due to the high rates of its intrinsic corrosion. Notably, nickel filler addition accelerates corrosion in the heat-affected zone (HAZ). In carbon dioxide (CO2) environments, the presence of acetic acid (HAc) intensifies corrosion; yet, the application of morpholine as pH neutralizer effectively counters its effects. Imidazoline based corrosion inhibitor prove successful in PWC mitigation, particularly at elevated pH levels. Furthermore, Post Weld Heat Treatment (PWHT) significantly reduces hardness, aligning with a decrease in corrosion. Of paramount importance, this study not only examining the effects of individual factors, including microstructure, pH adjustment, corrosion inhibitors, and PWHT, but also scrutinizing their combined impacts. The integration of PWHT with pH adjustment and inhibitor injection yields corrosion rates below 0.1 mm/y, ensuring a remarkable 30-year service life even under challenging conditions. This study underscores the necessity of a comprehensive strategy, combining these factors, to effectively manage preferential weld corrosion in carbon steel weldments.

In this study, the physicochemical properties and molecular interactions between zirconium-based metal-organic framework (UiO-66) and three different ionic liquids based on bis(trifluoromethanesulfonyl)imide anion (EMIM+, BMIM+ and OMIM+) was performed via a combined experimental and computational approach. The ionic liquid loaded UiO-66 or IL@UiO-66 was synthesized and characterized to understand the host-guest interaction. Density functional theory calculation was performed to analyse the electronic structure of IL@UiO-66 to provide molecular insight on the dominant interactions occurred in the hybrid material. Results showed that all ILs were successfully incorporated into the micropores of UiO-66. The 3D framework was retained even after loaded with ILs as analyzed from XRD pattern. FTIR spectrum reveals that interactions of ILs with UiO-66 influenced by the alkyl chain length of the cation. The anion has a profound affinity with the UiO-66 due to the presence of electronegative atoms. Phase transition study from DSC suggested that the incorporation of ILs has stabilized the framework of UiO-66 by shifting the endothermic peak to a higher state. These findings were further elaborated with DFT calculation. Geometrical optimizations confirmed the structural parameter changes of UiO-66 when loaded with ILs. These was mainly contributed by the non-covalent interactions which was confirmed by the reduced density gradient scattered plot. Another important findings are the strength of hydrogen bonding at the host-guest interface was influenced by the alkyl chain length. The molecular orbital analysis also shows that the size of alkyl chain influence the reactivity of the hybrid material. The present study provides fundamental insights on the molecular interaction of UiO-66 and ILs as a hybrid material, which can open new possibilities for advanced material for metal-organic framework applications in energy storage system, catalysis, gas storage and medicinal chemistry.

Spiro-OMeTAD is a widely used hole-transporting material (HTM) that plays a crucial role in achieving highly efficient perovskite solar cells (PSCs). In this work, a series of demethylated functionalized spiro-OMeTAD-based derivatives with different numbers of hydroxyl substituted groups (named as SOH2 , SOH4 , and SOH6 ) were synthesized, and their thermal, optical, electrical, and electrochemical properties have been investigated as potential HTMs for PSCs. It has been found that the molecule with six hydroxyl substituted groups on the spiro-OMeTAD-based structure SOH6 exhibited the highest glass transition temperature ( T _g ) and melting point ( T _m ) as compared to SOH2 and SOH4 molecules. The UV–vis absorption spectra portrayed a distinct pattern with the increase in hydroxyl substituted groups as it was slightly blue-shifted for the SOH6 molecule compared to red-shifted for SOH2 and SOH4 molecules. Carrier mobility shows a notable improvement with the hydroxyl substitution. The density functional theory (DFT) has provided useful insight into identifying the chemical stability of spiro-OMeTAD derivatives. In the device simulation, hydroxyl-substituted spiro SOH2 was found to outperform its pristine counterpart, achieving a peak PCE of 17.61% with a V _oc of 0.98 V, a J _sc of 22.69 mA cm ^−2 , and an FF of 80.67% within the device structure FTO/TiO _2 /MAPbI _3 /HTMs/Au. This investigation provided insight into the development of novel spiro-OMeTAD-based derivatives with enhanced optoelectronic properties and showed promising potential for addressing the limitations of traditional HTMs in PSCs.

Chemotherapy is the most common treatment for all cancer patients but this treatment poses many side effects due to lack of drug’s selectivity. To overcome this problem, utilizing a better and more effective delivery agent is the solution. Mesoporous silica nanoparticles (MSNs) emerged as a promising platform in development of drug delivery agent. This is due to its desirable properties such as tunable pores, large surface area, good biocompatibility and easy functionalization. Furthermore, these properties can be tuned through the utilization of alternative template such as pyridinium ionic liquid. Besides, by employing surface functionalization, the effectiveness of MSNs as drug delivery agent may also increase. This work reported the usage of 1-hexadecylpyridinium bromide ionic liquid as template for MSNs production and the surface of MSNs was then further functionalized via post – grafting method in order to obtain MSN – NH2, MSN – SH and MSN – COOH as drug carrier, respectively. These functionalized MSNs were then used to study the drug loading and drug release of hydrophilic drug, gemcitabine and hydrophobic drug, quercetin. For quercetin, MSN-NH2 had the highest drug loading percentage (72%) and slowest release (14%) in 48 h while for gemcitabine, it was found that MSN-COOH had the highest drug loading percentage (45%) and slowest release (15%) in 48 h. Based on the results, it is suggested that mesoporous silica nanoparticle with surface functionalization has suitable properties for controlled drug release which gives constant release behavior over a period of time to avoid repeated administration of drug where the drug is administered at a fixed dosage and regular time interval. Keywords: Mesoporous silica nanoparticles, Post-grafting, Organoalkoxysilanes, Anti-cancer drug, Drug delivery

A metal–organic framework (MOF) is a three-dimensional crystalline compound made from organic ligands and metals. The cross-linkage between organic ligands and metals creates a network of coordination polymers containing adjustable voids with a high total surface area. This special feature of MOF made it possible to form a host–guest interaction with small molecules, such as ionic liquid (IL), which can alter the phase behavior and improve the performance in battery applications. The molecular interactions of MOF and IL are, however, hard to understand due to the limited number of computational studies. In this study, the structural parameters of a zirconium-based metal–organic framework (UiO-66) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMIM][TFSI] were investigated via a combined experimental and computational approach using the linker model approach. When IL was loaded, the bond length and bond angle of organic linkers were distorted due to the increased electron density surrounding the framework. The increase in molecular orbital energy after confining IL stabilized the structure of this hybrid system. The molecular interactions study revealed that the combination of UiO-66 and [EMIM][TFSI] could be a promising candidate as an electrolyte material in an energy storage system.

In recent years, numerous research work has been conducted in order to find the most practical and cost-effective solution for corrosion issues in the oil and gas industry. Several studies have revealed that fatty hydrazide derivatives are the most suitable corrosion inhibitor for the application in the said industry. These compounds can also act as effective corrosion inhibitors in acidic medium with inhibition efficiency greater than 95%. This review summarizes and discusses the recent corrosion inhibitor development in acidic media from 2017 until 2021, focusing on fatty hydrazide derivatives. The significant findings and mechanisms of inhibition have been elucidated. In addition, intake on the computer simulation studies of fatty hydrazide inhibition properties is also included in this review. Finally, some suggestions for future research on corrosion inhibitors have been recommended.

Effective removal of 4-chloro-2-methylphenoxyacetic acid (MCPA), an emerging agrochemical contaminant in water with carcinogenic and mutagenic health effects has been reported using hydrothermally synthesized MIL-101(Cr) metal-organic framework (MOF). The properties of the MOF were ascertained using powdered X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM) and surface area and porosimetry (SAP). The BET surface area and pore volume of the MOF were 1439 m2 g−1 and 0.77 cm3 g−1, respectively. Artificial neural network (ANN) model was significantly employed for the accurate prediction of the experimental adsorption capacity (qe) values with minimal error. A rapid removal of the pollutant (99%) was recorded within short time (approx. 25 min), and the reusability of the MOF (20 mg) was achieved up to six cycles with over 90% removal efficiency. The kinetics, isotherm and thermodynamics of the process were described by the pseudo-second-order, Freundlich and endothermic adsorption, respectively. The adsorption process is spontaneous based on the negative Gibbs free energy values. The significant correlation between the experimental findings and simulation results suggests the great potential of MIL-101(Cr) for the remediation of MCPA from water matrices.

Recently, pharmaceutical pollutants in water have emerged as a global concern as they give threat to human health and the environment. In this study, graphene nanoplatelets (GNPs) were used to efficiently remove antibiotics sulfamethoxazole (SMX) and analgesic acetaminophen (ACM) as pharmaceutical pollutants from water by an adsorption process. GNPs; C750, C300, M15 and M5 were characterized by high-resolution transmission electron microscopy, Raman spectroscopy, X-ray diffraction and Brunauer–Emmett–Teller. The effects of several parameters viz. solution pH, adsorbent amount, initial concentration and contact time were studied. The parameters were optimized by a batch adsorption process and the maximum removal efficiency for both pharmaceuticals was 99%. The adsorption kinetics and isotherms models were employed, and the experimental data were best analysed with pseudo-second kinetic and Langmuir isotherm with maximum adsorption capacity (Qm) of 210.08 mg g−1 for SMX and 56.21 mg g−1 for ACM. A regeneration study was applied using different eluents; 5% ethanol-deionized water 0.005 M NaOH and HCl. GNP C300 was able to remove most of both pollutants from environmental water samples. Molecular docking was used to simulate the adsorption mechanism of GNP C300 towards SMX and ACM with a free binding energy of −7.54 kcal mol−1 and −5.29 kcal mol−1, respectively, which revealed adsorption occurred spontaneously.

Searching for a suitable electrolyte in a lithium-ion battery is a challenging task. The electrolyte must not only be chemically and mechanically stable, but also be able to transport lithium ions efficiently. Ionic liquid incorporated into a metal–organic framework (IL@MOF) has currently emerged as an interesting class of hybrid material that could offer excellent electrochemical properties. However, the understanding of the mechanism and factors that govern its fast ionic conduction is crucial as well. In this review, the characteristics and potential use of IL@MOF as an electrolyte in a lithium-ion battery are highlighted. The importance of computational methods is emphasized as a comprehensive tool to investigate the atomistic behavior of IL@MOF and its interaction in electrochemical environments.

Ionic liquids (ILs) were used in the dissolution of oil palm biomass, primarily empty fruit bunches (EFB), oil palm fronds (OPF), and oil palm trunks (OPT). These ILs acted as alternative solvents that could dissolve biopolymer molecules up to 5 wt.%. The IL, [emim][OAc] was the best solvent, dissolving EFB, OPF, and OPT of 99%, 100%, and 97%, respectively, at 100 ⁰C and 16 h. The lignin content of the regenerated oil palm solids for all biomass was quantified and showed significant reduction up to 35%; fiber length was also reduced as the heating time increased after IL dissolution. Also, the effect of ILs on the different parts of oil palm biomass fibers was thoroughly studied. The lignin content was quantified.

The antiradical efficiency (AE) and kinetic behavior of a new ferulate-based protic ionic liquids (PILs) were described using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay. The reduction of the DPPH free radical (DPPH•) was investigated by measuring the decrease in absorbance at 517 nm. The time to reach steady state for the reaction of parent acid (ferulic acid) and synthesized PILs with DPPH• was continuously recorded for 1 h. Results revealed that the AE of 2-butylaminoethanol ferulate (2BAEF), 3-dimethylaminopropanol ferulate (3DMAPF) and 3-diethylaminopropanol ferulate (3DEAPF) PILs have improved compared to ferulic acid (FA) as the reaction class changes from low to medium. This attributed to the strong hydrogen abstraction occurred in the PILs. Furthermore, these PILs were found to have a good kinetic behavior compared to FA due to the high rate constant (k2) (164.17, 242.84 and 244.73 M−1 s−1, respectively). The alkyl chain length and more alkyl substituents on the nitrogen atom of cation were believed to reduce the cation-anion interaction and speed up the hydrogen atom transfer (HAT) and electron transfer (ET) mechanisms; hence, increased rate constant was observed leading to a strong antioxidant activity of the synthesized PILs.

This paper reports the synthesis of a series of new tetraethylammonium-based amino acid chiral ionic liquids (CILs). Their physico-chemical properties, including melting point, thermal stability, viscosity and ionic conductivity, have been comprehensively studied. The obtained results indicated that the decomposition for these salts proceeds in one step and the temperature of decomposition (Tonset) is in the range of 168–210 °C. Several new CILs prepared in this work showed high ionic conductivity compared to the amino acid ionic liquids (AAILs) found in the literature.

Kojic acid is widely used to inhibit the browning effect of tyrosinase in cosmetic and food industries. In this work, synthesis of kojic monooleate ester (KMO) was carried out using lipase-catalysed esterification of kojic acid and oleic acid in a solvent-free system. Response Surface Methodology (RSM) based on central composite rotatable design (CCRD) was used to optimise the main important reaction variables, such as enzyme amount, reaction temperature, substrate molar ratio, and reaction time along with immobilised lipase from Candida Antarctica (Novozym 435) as a biocatalyst. The RSM data indicated that the reaction temperature was less significant in comparison to other factors for the production of a KMO ester. By using this statistical analysis, a quadratic model was developed in order to correlate the preparation variable to the response (reaction yield). The optimum conditions for the enzymatic synthesis of KMO were as follows: an enzyme amount of 2.0 wt%, reaction temperature of 83.69°C, substrate molar ratio of 1:2.37 (mmole kojic acid:oleic acid) and a reaction time of 300.0 min. Under these conditions, the actual yield percentage obtained was 42.09%, which is comparably well with the maximum predicted value of 44.46%. Under the optimal conditions, Novozym 435 could be reused for 5 cycles for KMO production percentage yield of at least 40%. The results demonstrated that statistical analysis using RSM can be used efficiently to optimise the production of a KMO ester. Moreover, the optimum conditions obtained can be applied to scale-up the process and minimise the cost.

The asymmetric unit of the title compound, C8H20N+·C4H5O5−·1.36H2O, contains two independent ion pairs, with similar conformations, and three water molecules of crystallization, one water molecule haing a site-occupancy factor of 0.721 (5). Intramolecular O—H...O hydrogen bonds, involving the hydroxy groups and an O atom of each carboxylate anion, generate five-membered rings involving S(5) ring motifs. In the crystal structure, molecules are linked together by water molecules through four-membered O—H...O—H...O—H interactions to form one-dimensional infinite chains along the a axis. Since the molecules are also linked into one-dimensional infinite chains along the b axis, molecular sheets parallel to the (001) plane are created. Overall, the crystal structure is stabilized by two intramolecular O—H...O hydrogen bonds, nine intermolecular O—H...O and ten C—H...O hydrogen bonds.

In the crystal structure of the title compound, C8H20N+·C4H5O6−·2H2O, the ions and water molecules are linked via O—H...O and C—H...O hydrogen bonds, forming a two-dimensional network parallel to (001).