Acidic Media Research Articles

Multilayer‐coated polyphenylsulfone membranes with superior antifouling properties of PEG‐NH2 hydrogel for ultrafiltration process

AbstractThis study explores application of poly (ethylene glycol) (PEG)‐based hydrogel to improve the antifouling properties and performance of polyphenylsulfone (PPSU) membrane. The modification of PPSU membrane was performed via coating different ratio of polydopamine (PDA) to 3‐(aminopropyl)triethoxysilane (APTES) as interlayer on surface of PPSU membrane followed by grafting of PEG‐NH2 hydrogel. The as‐prepared membranes were characterized and results confirmed the successful coating of interlayer and hydrogel. The performance of as‐prepared membranes was measured using pure water flux, humic acid (HA), and bovine serum albumin (BSA) separation. The PDA‐APTES (50:50) was selected as the optimal interlayer to graft hydrogel with respect to their superior effect on properties of resultant membrane. The permeate flux and HA rejection increased from 35.2 LMH and 55% for pristine PPSU membrane to 83 LMH and 96% for optimal membrane. For optimal membrane the flux recovery ratio (FRR) value of 96% and 93% determined for BSA and HA separation, respectively. Chemical stability examined and the results confirmed that the hydrogel‐coated membrane was more stable in acidic media compared with alkali media. In summary, the simultaneous presence of the interlayer and the grafted hydrogel had a great impact on the morphology, performance, anticlogging properties, and acid resistance of the modified membranes.

Anticorrosion Behavior of Persea macrantha Leaf Extract on Aluminium in Acidic Medium

Anticorrosion Behavior of Persea macrantha Leaf Extract on Aluminium in Acidic Medium

Improving Biological Performance of 3D-Printed Scaffolds with Garlic-Extract Nanoemulsions.

Complex bone diseases such as osteomyelitis, osteosarcoma, and osteoporosis often cause critical-size bone defects that the body cannot self-repair and require an advanced bone graft material to repair. We have fabricated 3D-printed tricalcium phosphate bone scaffolds functionalized with garlic extract (GE). GE was encapsulated in a nanoemulsion (GE-NE) to enhance bioavailability and stability. GE-NE showed ∼73% drug encapsulation efficiency, with an average particle size of 158 nm and a zeta potential of -14.2 mV. Release of GE-NEs from the scaffold displayed a controlled and biphasic release profile at both acidic and physiological mediums. Results from the osteosarcoma study show that GE-NE demonstrated ∼88% reduction in cancer cell growth while exhibiting no cytotoxicity toward bone-forming cells. Interaction for the functionalized scaffold with Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa showed a substantial reduction in bacteria growth by more than 90% compared to the unfunctionalized scaffold. These findings demonstrate the potential of GE-NEs-treated porous scaffolds to treat bone-related diseases, particularly for non-load bearing applications.

Unveiling the tribological and corrosion characteristics of Ti20-Al16-V16-Fe16-Ni16-Cr16 high-entropy alloy developed via spark plasma sintering

This research explores the corrosion resistance and anti-wear property of near-equimolar Ti20-Al16-V16-Fe16-Ni16-Cr16 High Entropy Alloys (HEAs), fabricated at varying temperatures through spark plasma sintering (SPS) procedure. The alloy powders were processed and sintered at temperatures ranging from 700°C to 1100°C, and the resulting HEAs underwent comprehensive characterization. The tribological behavior of these sintered HEAs and their corrosion response in sulfuric and chloride environments were systematically investigated. Microstructural analyses were conducted before and after exposure to corrosive media using a scanning electron microscope. Notably, the assessments in both acid and salt media revealed that HEAs sintered at 1100°C exhibited the highest corrosion resistance, whereas those sintered at 700°C displayed the least resistance. The wear rate is improved by 130% over Inconel 718 alloy in the created HEA. This research signifies the potential of Ti20-Al16-V16-Fe16-Ni16-Cr16 HEA prepared through tailored SPS procedures, as corrosion and wear resistance alternatives surpass the performance of Ti6AlV4 and traditional alloys.

Sodium salt of dodecyl benzene sulphonic acid as an effective corrosion inhibition for different heat-treated steel in sulphuric acid medium

Abstract The purpose of this work is to use electrochemical and gravimetric techniques to investigate the inhibition of DBSS on the corrosion of heat-treated dual-phase AISI 1040 steel in a 0.5 M sulphuric acid solution at 35 °C. The corrosion studies are performed by potentiodynamic polarization study (PDP), electrochemical impedance study (EIS), and gravimetric method. To confirm the inhibition surface characterization like x-ray diffraction technique (XRD) analysis, scanning electron microscopy (SEM), and EDS analysis are performed. Depending on the phase change of metals due to heat treatment, the corrosion inhibition of the heat-treated metal increased when it was exposed to 0.5 M H2SO4 at 35 °C in the presence of dodecyl benzene sulphonic acid sodium salt (DBSS) inhibitor. The highest inhibition efficiency of 63 %, 82 %, 87 %, 43 %, and 63 % was obtained for AISI 1040 steel at heat treatment conditions of Normalized, Quenched at 700 °C, Quenched at 750 °C, Quenched at 790 °C and Quenched at 900 °C respectively. In the gravimetric and electrochemical study, the IE increases with the increase with the concentration of DBSS unto 75 % from gravimetric analysis and 87 % from PDP analysis for Quenched at 750 °C and 790 °C respectively. The metal protection is achieved by heat treatment process as well as by using DBSS as inhibitor. Corrosion inhibition on the metal's surface was confirmed by SEM and XRD. In addition, the adsorption of DBSS on the anodic and cathodic sites of the metal surface was well explained.

Cu‐promoted Access to 1,4‐Diazine‐fused Isoindoles Through Concomitant Csp3‐N and Csp2‐N Bonds Formation Starting from Constrained N,O‐acetals

Scarce dihydro‐1,4‐diazinoisoindole framework bearing two points of diversity was prepared through interesting cascade process based on concomitant Csp3‐N and Csp2‐N bonds formation. This approach consists on amidation in basic medium of tosyl group by nucleophilic substitution followed by Cu‐mediated Goldberg reaction in same operation. The required β‐bromoenamide bearing a tosyl group was obtained by tosylation of fused brominated N,O‐acetals for the first time in acidic medium using submolar amounts of PTSA. The obtained piperazines act as a powerful reaction intersection as illustrated by the formation of N‐heterocyclic system via the intramolecular interception of enamide function.

Effect of polyelectrolyte (PAA) on the dynamics of weakly charged microemulsion droplets in acidic medium

We use the dynamic light scattering technique (DLS) to study the dynamic behavior of complex constituted by weakly charged microemulsion in the presence of polyelectrolyte. We investigated the impact of adding oppositely charged polyacid (PAA), which is a pH-dependent polyelectrolyte, on the dynamics of charged microemulsion nanodroplets in an acidic medium at pH = 4.5 when the polyacrylic acid are partially charged. In a diluted regime, two diffusive relaxation modes are seen when adding (upon addition) the polyacrylic acid PAA to the microemulsion nanodroplets due to collective diffusion and self-diffusion fluctuations. In the concentrated regime, we observed three diffusive relaxation modes when charged microemulsion nanodroplets complexed with oppositely charged polyacrylic acid. We attribute the two first relaxation modes to the collective diffusion (fluctuation of concentration) and self-diffusion of the microemulsion nanodroplets. The third mode which is a slower relaxation mode; we attribute this relaxation process to the motion of the network formed by the polyacid PAA and microemulsion nanodroplets, or “breathing mode” of the network.

Influencing Factors and Stimulus-Sensitivity of Chitosan/Polymethacrylic Acid (CS/PMAA) Nanogels as Nanocarriers

ABSTRACT Nanogel, nanosized hydrogel, can contribute to biomedical and pharmaceutical, especially in drug delivery, due to its enthralling properties. Small size, large surface area, hydrophilicity, and stimulus responsiveness of nanogel ameliorate tissue penetration, drug loading capacity, and targeted drug delivery. The current study prepared nanosized, pH-sensitive, biocompatible, and stable chitosan/polymethacrylic acid (CS/PMAA) based nanogels using MBA as a crosslinker and APS as an initiator. FTIR confirmed the reaction between functional groups to synthesize nanogels sufficiently in a spherical shape, as affirmed by a FESEM. DLS data revealed nanosized particles with a size range of 70–170 nm and a range of 6–13 for polydispersity index (PDI). A study showed that 2% of MBA crosslinker is sufficient to achieve the desired crosslinking in 60 minutes reaction time (RT) with nanogel size ~ 92 nm. Increasing RT from 30 to 80 minutes during nanogel synthesis demonstrated a decrease in nanogel sizes from 186–73 nm. Synthesized nanogels have shown pH sensitivity (stimuli responsiveness) in acidic and alkaline mediums with an increase in particle size in pH-2 (~144 nm) and pH-8 (~280 nm) compared to intermediate pHs. The pH sensitivity of nanogels by changing the size per the suspended medium’s pH is crucial for prolonged systemic circulation and targeted drug delivery. Moreover, nanogels have shown good colloidal stability with zeta potential (ZP) +28 mv in acidic and −38 mv alkaline mediums. DSC and XRD results demonstrated thermal stability and amorphous morphology of nanogels, respectively. BET surface analysis revealed the surface area of nanogels in the range of 65–68 cm2/g with an average pore size of 28–32 nm. In-vitro cytotoxicity in the L-929 cell line by MTT assay established the cell viability (>70%) after 24 hours of incubation, substantiating the non-toxicity and biocompatibility of nanogels as nanocarriers for drug delivery.

Effect of substitution on corrosion inhibition properties of 4-(substituted fluoro, chloro, and amino) Benzophenone derivatives on mild steel in acidic medium: A combined Electrochemical, surface characterization and theoretical approach

Background: In this study, three mono-substituted Benzophenone (BP) derivatives, 4-Fluorobenzophenone (4-F.BP), 4-Chlorobenzophenone (4-C.BP), and 4-Aminobenzophenone (4-A.BP) were investigated using a combined electrochemical, surface characterization and theoretical approach. Methods: In experiment, the effectiveness of 4-F.BP, 4-C.BP, and 4-A.BP in inhibiting mild steel corrosion in a 1 N HCl solution were investigated using gravimetric measurements at several temperatures (303–333 K), electrochemical measurements (Potentiodynamic Polarization (PDP), and Electrochemical Impedance Spectroscopy (EIS)), UV–visible analysis, Surface morphology test (SEM and EDAX analysis, AFM analysis, water contact angle measurement, XPS analysis) as well as theoretical studies. Significant findings: Increase in the inhibitor concentrations (160, 200, 240 and 280 ppm) exhibited a maximum percentage of inhibition efficiency (IE %) of 83.75 %, 88.75 %, and 93.75 % for 280 ppm of 4-F.BP, 4-C.BP, and 4-A.BP respectively at 303 K. However, with increase in the temperature from 303 to 333 K, IE % furthermore reduced to 52.41 %, 57.24 %, and 66.20 % at 333 K. The potentiodynamic polarization plots revealed that all molecules acted as mixed-type corrosion inhibitors and had an exceptional ability to inhibit the anodic reaction. Moreover, Scanning Electron Microscopy (SEM), Atomic force microscopy (AFM), and Contact angle measurement (CAM) confirms the formation of protective layer on the metal surface by the chosen inhibitors. The X-ray Photoelectron Spectroscopy (XPS) data confirms the bonding interaction between the functional groups and the metal surface. Furthermore, Density Functional Theory (DFT) calculation and Molecular Dynamics simulations (MD) were carried out to understand inhibition's molecular/atomic mechanisms. In summary, the suggested benzophenone derivatives are effective and economical anticorrosion agents for mild steel surfaces exposed to aggressive environments.

3D printed tinidazole tablets coupled with melt-extrusion techniques for formulating child friendly medicines

This study investigates the feasibility of fabrication of poly(1-vinyl-2-pyrrolidone) (Kollidon®25)-mediated filaments for producing tinidazole (TNZ)-loaded, customizable, child-friendly tablets (with varying shapes and sizes) using hot melt extrusion (HME) coupled with fused deposition modeling (FDM) technology. Kollidon®25, chosen for its ability to enhance the dissolution of TNZ (a BCS Class II drug), was evaluated for polymer-drug compatibility through Hansen solubility, polarity, and interaction parameter analyses, confirming good miscibility and affinity between TNZ and Kollidon®25. Placebo- and TNZ-loaded filaments were prepared in different ratios using HME, followed by the development of 3D-printed tablets via FDM. The fabricated batches of placebo and TNZ-loaded 3D tablets were characterized, and it was found that they had an average weight variation of 270.41 ± 7.44 mg and 270.87 ± 9.33 mg, hardness of 155.01 ± 11.79 N and 265.3 ± 7.62 N, and friability of 0.1583 ± 0.0011 % and 0.2254 ± 0.0013 %. Amorphization was confirmed by differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) analysis. Scanning electron microscopy (SEM) revealed a layer-by-layer pattern with tiny fractures on the tablet surfaces, which enhanced media penetration, resulting in improved dissolution profiles. The TNZ release profile showed complete 100 % release within 2.0 h in a gastric acidic medium. These findings support the potential of Kollidon®25 to create customizable, child-friendly, 3D-printed dosage forms with different shapes and sizes for TNZ delivery, offering a unique approach to paediatric medications.

Removal of an organophosphate insecticide from aqueous media using phyllosilicate clay: multivariable optimization, nonlinear kinetic modelling and thermodynamic study

The excessive and irrational use of organophosphate insecticides in our lives has resulted in a serious environmental problem, necessitating the proposal of novel and cost-effective plans to remove these organophosphate insecticides from agricultural or industrial wastewater. In this approach, we investigated the use of phyllosilicate clay as a low-cost and environmentally friendly adsorbent to eliminate an organophosphate insecticide (Diazinon DZN) from an aqueous medium. To achieve an adequate elimination of this insecticide from contaminated water, three main parameters including clay dose ( D c ) (0.1–1.5 g L−1), medium pH (5–9), and initial DZN concentrations ( C DZN ) (55–40 mg L−1) were optimized using a multivariable optimization based on Box-Behnken Design (BBD). The response surface method (RSM) and composite desirability function technique were used to find the ideal conditions for the three input variables and the adsorption amount ( Q e ) was selected as the output variable. The higher adsorption amount ( Q max ) was achieved with an adsorbent amount of 1.5 g L−1 in an acidic medium (pH = 5) at room temperature and a Diazinon initial dose of 25.85 mg L−1, with a maximum adsorbent loading of 12.20 mg g−1. The nonlinear modeling study showed that the adsorption kinetics of Diazinon follows the pseudo-second-order model. The thermodynamic study shows that the DZN removal process is exothermic, spontaneous, and of a stable configuration.

Corrosion inhibition assessment of a sustainable inhibitor from the weed plant (Pouzolzia zeylanica L.) on SS-410 surface in 0.5 M HCl acidic medium

BackgroundThe research has looked into the potential of plant extracts as natural corrosion inhibitors as an alternative to synthetic ones. The study aims to investigate the ability of the weed plant Pouzolzia zeylanica L. extract (PZE) to prevent corrosion of stainless steel-410 in a 0.5 M HCl acidic medium. MethodIn this work, the leaf extract of PZE is prepared in water, and the functional activity of the prepared PZ water extract (PZE)is evaluated using various techniques. Both electrochemical and gravimetric techniques are employed in this study. The inhibitor from PZ inhibits the anodic region on the SS-410 surface active sites through straightforward adsorption. Experimental techniques such as UV–visible spectroscopy, FTIR, LC-MS, SEM, AFM, EDX, EIS, and computational studies demonstrate the formation of protective layers under inhibiting conditions. The gravimetric data confirms monolayer adsorption, following the Langmuir adsorption isotherm. Significant findingsThe data obtained demonstrate that when SS-410 is immersed directly in a corrosive solution containing dissolved inhibitor molecules, it effectively prevents corrosion. Therefore, increasing the concentration of this chemical improves its inhibitory efficiency. Indeed, the PZ inhibitor achieved a favourable experimental outcome with an efficacy of 95 % at 400 mg/L in 0.5 M HCl. Based on polarization analysis, the corrosion inhibitor exhibits anodic nature for SS-410 in 0.5 M HCl.

Synthesis and characterization of Gellan gum-based hydrogels for the delivery of anticancer drug etoposide

Present research work reports the synthesis of Gellan gum (Gg) and methacrylic acid (MA) based grafted hydrogels (Gg-cl-poly(MA)) crosslinked using N, N′– methylene-bis-acrylamide (MBA) and the evaluation of their efficiency to be used as a sustained drug delivery carrier for anticancer drug i.e., etoposide. Various characterization techniques like Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) confirmed the grafting of Gg with MA and the formation of crosslinked Gg-cl-poly(MA) hydrogel polymer. The synthesized hydrogel showed pH-dependent swelling properties and exhibited a maximum swelling capacity of 867 % under optimized environmental conditions. The Gg-cl-poly(MA) was biocompatible and non-cytotoxic, which was confirmed by the hemolytic and cytotoxic tests. The release dynamics of etoposide from the Gg-cl-poly(MA) polymer matrix was checked under specific physiological conditions. Drug release was found to be significantly higher in the acidic medium, followed by the neutral and alkaline medium. This clearly indicated that etoposide drug release through synthesized hydrogel was stomach-specific and it is effective for the treatment of stomach cancer. The release mechanism of the etoposide drug was a Fickian-type diffusion mechanism in the acidic medium and a non-Fickian-type diffusion mechanism in the neutral and alkaline medium. The release profile of the etoposide was best fitted to the first-order rate model. The results showed that the synthesized hydrogel (i.e., Gg-cl-poly(MA)) was biocompatible, non-toxic, and could be used for the treatment of stomach cancer.

A one-dimensional bacterial cellulose nano-whiskers-based binary-drug delivery system for the cancer treatment

It's currently a challenge to design a drug delivery system for chemotherapy with high drug contents and minimal side effects. Herein, we constructed a novel one-dimensional binary-drug delivery system for cancer treatment. In this drug delivery system, drugs (doxorubicin (DOX) and resveratrol (RES)) self-assemble on bacterial cellulose nano-whiskers (BCW) and are subsequently encapsulated by polydopamine (PDA) with high encapsulation efficiencies (DOX: 81.53 %, RES: 70.32 %) and high drug loading efficiencies (DOX: 51.54 %, RES: 36.93 %). The cumulative release efficiencies can reach 89.27 % for DOX and 80.05 % for RES in acidic medium within 96 h. The BCW/(DOX + RES)/PDA can enter tumor cells easily through endocytosis and presents significant anti-cancer effects. Furthermore, the released-RES plays a protective role in normal cells through up-regulation of antioxidant enzymes activities and scavenging of reactive oxygen species. Taken together, the one-dimensional BCW/(DOX + RES)/PDA binary-drug delivery system can be used for the anticancer treatment along with slight side effects.

Defatted microalgae Haematococcus pluvialis: A sustainable source for gold recovery

The defatted microalgae Haematococcus pluvialis (HP), obtained from various production lots, were subjected to two different treatments: drying without chemical treatment (DH1, DH2, and DH3) and treatment with concentrated sulfuric acid (TH1, TH2, and TH3). These treated materials were employed as efficient and eco-friendly adsorbents to investigate the adsorption behavior of Au(III) in acidic chloride media. The treated adsorbents demonstrated exceptional performance, achieving 100 % adsorption of Au(III) across a broad range of hydrochloric acid (HCl) concentrations from 0.01 to 5.00 M, whereas the dry adsorbents exhibited up to 90 % adsorption only at low HCl concentrations. Both dry and treated adsorbents exhibited superior selectivity for Au(III) in the presence of a mixture of precious metal ions. The adsorption isotherms of Au(III) followed the Langmuir type of adsorption mechanism, and the maximum adsorption capacities for Au(III) were estimated as 1.57, 0.88, and 1.52 mol kg–1 for DH1, DH2, and DH3, and 6.17, 4.80, and 5.37 mol kg–1 for TH1, TH2, and TH3, respectively. The adsorbed Au(III) ions were reduced to the elemental state, as confirmed by X-ray diffraction patterns, scanning electron microscopy/energy-dispersive X-ray analyses, and digital micrographs of the adsorbents after Au(III) adsorption. Successful desorption of the adsorbed Au(III) was achieved using acidic thiourea solution.

Thermoacid Behavior of Serpentinite of the Zhitikarinsky Deposit (Kazakhstan).

Thermoacid behavior of serpentinite from the Zhitikarinsky field (g. Zhitikara, Kazakhstan). The character of dissolution of heat-treated serpentinite in a narrow temperature range of 600-750 °C is investigated, where the crystal lattice of the structural structure of chrysotile in sulfuric acid is destroyed. The X-ray and chemical analysis of the products of dissolution of heat-treated serpentinite at 600 °C, 725 °C and 750 °C in sulfuric acid solution show that the reason for the increase in the reactivity of heat-treated serpentinite at 725 °C and 750 °C with respect to the acidic medium and the degree of magnesium extraction into sulfate solution is the formation of periclase (MgO) in the serpentinite composition after heat treatment of them within a temperature range of 600-750 °C. The results were discussed using data obtained by conducting a thermodynamic evaluation of probable reactions during the thermoacid treatment of serpentinite, phase compressions of heat-treated serpentinite at 600-750 °C, and after its acid treatment at 1.0 M H2SO4.

Mitigation of mild steel corrosion using Schiff base-derived inhibitors in acidic media: An experimental and theoretical study

Corrosion presents a substantial hurdle in the oil and gas industry, and corrosion inhibitors represent an economically viable strategy for control and prevention. As operating conditions in oil and gas extraction become increasingly harsh, factors such as cost, availability, and service temperature significantly influence inhibitor selection. While there is a wealth of literature on organic corrosion inhibitors, many exhibit a notable decrease in effectiveness at elevated temperatures, hindering their industrial application. To address this issue, we synthesized a novel Schiff base derivative, 1-((E)-(4-chlorophenylimino)methyl)naphthalen-2-ol (E4CMN), and investigated its effectiveness in inhibiting corrosion on Q235 immersed in a 1 M HCl. E4CMN adsorbs onto the surface by forming strong π-d interactions with Fe through the delocalized π electrons in its conjugated structure, effectively blocking the attack of corrosive particles towards the metal surface and consequently suppressing metal corrosion. Our study demonstrates that E4CMN exhibits maximum efficiencies of 96.9 % at a concentration of 250 mg L−1. Importantly, E4CMN shows insensitivity to service temperature, maintaining an 84.4 % corrosion inhibition efficiency even when exposed to 75 °C. This work provides novel insights into mechanism of inhibition of mild steel corrosion by Schiff base derivatives in acidic environments and offers valuable considerations for the development and selection of corrosion inhibitors for high-temperature applications.

Robust self-supporting MoS2@Ni2B-GO/CNT electrode for enhanced hydrogen evolution reaction in acidic medium

Molybdenum sulphide (2D-MoS2) promises great potential as a hydrogen evolution (HER) catalyst, especially, when combined with conductive carbon supports like graphene oxide (GO) and carbon nanotubes (CNT). However, the hydrophobic nature of these carbon supports limits the catalytic potential of MoS2. To overcome this, we introduced hydrophilic Nickel Boride (Ni2B) into GO/CNT electrodes (Ni2B-GO/CNT), enhancing wettability (Contact angle-25.3°) and HER activity. By hydrothermally depositing MoS2 onto the hydrophilic Ni2B-GO/CNT electrode, we fabricated a self-supporting MoS2@Ni2B-GO/CNT electrode. The MoS2 deposition led to the formation of MoS2@Ni2B-GO/CNT heterostructure with multiple interfaces, favoring interfacial electronic redistribution (XPS) to significantly improve the HER activity. Thus, the proposed MoS2@Ni2B-GO/CNT electrode exhibited an excellent durability of 100 h (97%) and an overpotential of 224 mV at 10 mA cm−2 in acidic medium.

Comparative study of the structure and durability of commercial silicate glasses for food consumption and cosmetic packaging

Four commercial glass compositions were investigated to understand their mechanisms of alteration in light of the current and future regulations on food contact materials. Lead crystal (fine glassware), soda-lime (food and cosmetic containers), borosilicate (cookware) and barium glass (tableware) powders and slabs were altered for 3 years, in acetic acid (4% vol) at pH = 2.4 and 70 °C. The leaching solution was analyzed by ICP-AES while glass slabs were investigated by ToF-SIMS and Spectroscopic Ellipsometry. As a result, in acidic medium, the polymerization of the silicate network as well as the glass composition impacted the alteration rates and depleted depths of alkalis and earth-alkalis elements. Yet the rate of hydrolysis measured from the release of Si, remained similar under identical alteration conditions, whatever the glass structure and composition. For lead crystal glass, repolymerization of the silicate network was observed in the course of alteration.

Indole derivatives efficacy and kinetics for inhibiting carbon steel corrosion in sulfuric acid media

The global prevalence of metal corrosion is a significant challenge due to its detrimental effect. Environmentally friendly and non-hazardous alternatives for harmful and poisonous synthetic corrosion inhibitors are urgently necessary due to increasing environmental concerns and regulations prohibiting their application. In this study, indole molecules were employed as carbon steel corrosion inhibitors in acidic conditions. Gravimetrical and scanning electronic microscope (SEM) analysis was used in a preliminary investigation of indole as an organic inhibitor. The results revealed that adding indole to carbon steel before exposing it to sulfuric acid slowed and induced resistance to corrosion. The indole affixed themselves to the steel carbon surfaces, producing a barrier/protection for carbon steel. The efficacy of the indole in preventing corrosion was determined through the weight loss method. Temperature and inhibitory concentration effects on inhibition effectiveness under varying parameters were also reported. The temperatures employed were between 298 K and 328 K, while the inhibitor concentrations ranged from 1.2 × 10−3 M to 7.6 × 10−3 M, and both parameters significantly influenced corrosion inhibition effectiveness. The inhibitory mixture attained optimum efficacy in inhibiting corrosion, at 81 %, when the lowest and highest respective temperature and concentration were applied. The kinetic analysis was conducted under a range of temperatures to determine the reaction mechanisms of the inhibitor. The thermal adsorption isotherm of the inhibitor indicated that the surface adhered to Langmuir's adsorption isotherm. Additionally, investigations on corrosion and inhibition using the electrochemical impedance spectroscopy method (EIS) were conducted. This study can provide in-depth knowledge for advancing inhibitory science and engineering to enhance corrosion resistance in acidic media.