Seawater Solutions Research Articles

The Effectiveness Of Citric Acid As An Anti-Ectoparasite Of Marine Leech (Zeylanicobdella arugamensis) Through Soaking

Zeylanicobdella arugamensis infection causes health problems for cultured grouper. This study aims to determine the effectiveness of citric acid soaking as an anti Z. arugamensis ectoparasite. A total of ±120 Z. arugamensis were isolated from sick hybrid grouper (Epinephelus fuscoguttatus x E. lanceolatus) placed in Petri dishes (6 Petri dishes). Citric acid solution with 0, 50, 100, 150, 250, and 400 ppm was added to the petri plates. Immersion of Z. arugamensis was carried out for 30, 60, 90 and 120 minutes. Each 30 Z. arugamensis/treatment/30 minutes was taken and placed in 3 petri dishes (10 individuals/petri dish) filled with seawater. Observations were made on the response of Z. arugamensis. Comments were made on cocoon development into larvae. The citric acid safety test was conducted on cantang hybrid grouper infected with Z. arugamensis. A total of 3 test fish were soaked with citric acid solution in seawater at concentrations of 0, 150, 250, and 300 ppm. Observations of fish condition were made after 30 and 60 minutes of immersion. The results showed that citric acid concentrations of 250 and 400 ppm effectively killed Z. arugamensis (76.67±15.28-100%), and their cocoon development reached (0%). A citric acid concentration of 300 ppm is still safe to use for immersion of cantang hybrid grouper infected with Z. arugamensis for 60 minutes. Citric acid concentrations of 250-300 ppm can also release Z. arugamensis from the fish body. Citric acid has antiparasitic properties and lowers the pH of seawater.

Effect of water environment on mechanical behavior of coral aggregate concrete

The complex marine environment often exposes concrete to seawater and acidic conditions during its service life. To investigate the effect and mechanism of special water environments on coral sand concrete, forty-five Φ50 mm × 100 mm cylindrical coral concrete specimens were prepared and cured in freshwater, seawater and oxalic acid in this study. The specimens were cured for 7, 14, 28, 60 and 90 days, respectively. The physical and mechanical properties of the specimens under the lossless state and static failure state were tested through piezoelectric transducer (PZT) test and uniaxial compression test. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed for analyzing the mineral composition and microstructure of the specimens. The results show that the compressive strength of the specimens in seawater and freshwater initially increased and then stabilized with the curing age, whereas in oxalic acid it initially increased and then decreased. The compressive strength of the specimens at 90 days in freshwater, seawater and oxalic acid solution have increased by 54%, 18% and 21%, respectively, compared to that at 7 days. A combination analysis using microscopic and macroscopic test indicated that the completion time required for hydration in freshwater, seawater and oxalic acid solution was 28, 28 and 60 days, respectively. This study suggests that Cl− in seawater accelerates the cement hydration process, improving the early mechanical properties of specimens. During the later hydration process, the soluble CaCl2 and expansile Mg(OH)2 generated during the later hydration process which reduces the strength. In oxalic acid solution, a dense calcium oxalate coating produced through the reaction between oxalic acid and CaCO3 would reduce the degree of hydration. The formation of CO2 would increase the porosity of specimens, thereby weakening the mechanical strength of the concrete.

Electrochemical behaviour of the Al-20Mg alloy in synthetic seawater with alkaline pH

The corrosion of Al-(20 wt%) Mg alloy in artificial seawater solution at different pH, using potentiodynamic polarization, polarization resistance and electrochemical impedance spectroscopy techniques was assessed. The results showed that the effect of the pH of the artificial seawater solution promoted susceptibility to localized corrosion by dissolution of the oxide layer, which is naturally present on the surface of the aluminium alloy. X-ray diffraction analysis shows the presence of Al3Mg2 intermetallic phase which promotes the dissolution of the aluminium phase, and the evolution of hydrogen. The activation mechanism at the oxide-free zones and the diffusion through the corrosion products scale were associated with continuous formation of Al(OH)3 and Mg(OH)2 at the Al-Mg alloy interface, with minor protective effect as pH increases. The electrochemical behaviour of the Al-(20 wt%)Mg alloy in artificial seawater solution at pH 14 suggests potential application in hydrogen evolution due to its high surface catalytic activity. Results were complemented by scanning electron microscopy and X-ray diffraction characterization.

Features of the use of sodium hypochlorite in agriculture. Technology of solution preparation in a small-sized mobile device

The purpose of the presented work is to develop a technology and a small–sized device for producing electrolytic sodium hypochlorite of high activity with respect to biofactors, safe to handle and negative impact on the environment. The implementation of the electrochemical method of obtaining consists in the electrolysis of an aqueous solution of sodium chloride or seawater in an electrolyzer pretreated with high-voltage discharge pulses. The proposed technical solution makes it possible to increase the yield of electrolysis products and the reactivity of sodium hypochlorite due to the structural adjustment of both water and sodium chloride molecules. A portable low-power device for the production of hypochlorite in farms, characterized by multifunctional use, has been developed for disinfection, disinfection and deratization. The novelty of the work is confirmed by the need to develop a technology for obtaining a disinfectant by activating water with a high-voltage discharge, which improves the quality of hypochlorite for disinfection of water, organic waste from animal husbandry, pig and poultry farming, grain storage and pest control of agricultural and fruit and vegetable crops.

Study on DeNOx of NaClO2 in simulated seawater solution enhanced by hydrodynamic cavitation

Ship exhaust causes significant air pollution, and NOx is one of the most challenging pollutants to remove. In this study, we propose a novel method for denitrification (DeNOx) using NaClO2-simulated seawater solution enhanced by hydrodynamic cavitation. We investigate the impact of initial solution pH, temperature, NaClO2 concentration, and the inlet pressure of the hydrodynamic cavitation reactor on DeNOx efficiency. The results indicate that under optimal conditions, a 100 % DeNOx efficiency can be achieved with a NaClO2 concentration of 0.1 mmol/L. Cavitation enhances mass transfer by generating microjets and increasing the gas–liquid contact area. The oxidation of NO and NO2 by hydroxyl radicals and chlorine oxygen radicals produced through cavitation could potentially enhance NOx removal efficiency. The presence of dissolved salts in simulated seawater might boost cavitation activity by reducing vapour pressure and increasing interfacial tension, leading to the more robust collapse of cavitation bubbles and thereby reinforcing cavitation effects. In addition, the multiple reactive inorganic chlorinated radicals (Cl, HClO / ClOH·-, Cl2·-) formed in simulated seawater due to the presence of Cl- might also play an essential role in DeNOx. This study demonstrated that the DeNOx by NaClO2 in simulated seawater enhanced by hydrodynamic cavitation was a promising option for NOx removal, especially for ocean-going vessels.

Cellular and oxidative stress responses of Mytilus galloprovincialis to chlorpromazine: implications of an antipsychotic drug exposure study.

Introduction: Bivalve molluscs like Mytilus galloprovincialis are valuable bioindicators due to their filter-feeding lifestyle, wide distribution, and ability to concentrate xenobiotics. Studying the effects of pharmaceuticals on these molluscs is crucial given their presence in surface waters. This study investigated the response of M. galloprovincialis to chlorpromazine (Cpz), an antipsychotic with antiviral activity against influenza, HIV, and coronaviruses in human cells. Methods: In this study, we examined the 14-day impact of chlorpromazine (Cpz) on the model species M. galloprovincialis at two concentrations (Cpz 1: 12ng L-1 or 37 pM; Cpz 2: 12µg L-1 or 37nM). To ensure controlled exposure, a stock solution of Cpz was prepared and introduced into the tanks to match the intended concentrations. Seawater and stock solutions were refreshed every 48h. The primary focus of this study centered on evaluating cell viability, cell volume regulation, and oxidative stress indicators. Results: Although cell volume regulation, as assessed by decreasing regulatory volume Regulation volume decrease, did not show statistically significant changes during the experiment, digestive cell viability, on the other hand, showed a significant decrease (p < 0.01) in the Cpz 2 group, suggesting effects on the general health and survival of these cells. Biochemically, in both Cpz 1 and Cpz 2, superoxide dismutase activity increased, while catalase (CAT) decreased, causing an elevated lipid peroxidation thiobarbituric acid-reactive substances and protein carbonyls, particularly in the Cpz 2 group. The level of reduced glutathione (GSH) increased in both exposures, whereas the level of GSSG increased only in the Cpz 1 group. Consequently, the GSH/GSSG ratio was elevated in the Cpz 2 group only. Discussion: A comparison of the magnitudes of anti- and pro-oxidative manifestations indicated a pro-oxidative shift in both exposures. These findings show that Cpz induces non-specific symptoms of biochemical and cellular disturbances in M. galloprovincialis even at the low picomolar concentration.

Corrosion of Brass Fishing Vessel Propeller in Artificial Seawater

The propeller was an important component in the fishing vessels marine propulsion system. Brass was widely used as a fishing vessel propeller. Brass was chosen because it has good mechanical properties and good corrosion resistance. The content of seawater in Indonesia has levels of 3% – 3.5% NaCl. In addition to the level of Ion Cl-, environmental factors can affect corrosion rate of material or metal. The environmental factors that affect the corrosion rate are the level of salinity, pH, DO, temperature and TDS. The objective of the present work was to explain the corrosion rate of brass in artificial seawater in Indonesia with exposure time. The material used for research is fishing vessel propeller commercial in Indonesia market. Measurement of the corrosion rate of brass used the principle of weight loss according to ASTM G31-72 (2004). During the corrosion test, the artificial seawater solution was tested for its pH and salinity quality over time of immersion. The result of immersion brass in the artificial seawater shows that the corrosion rate decreases in 1-to-10-days exposure time due to the increase in salinity levels above 30‰. While the results of exposure time immersion above 15 days tends to increase the corrosion rate due to a decrease in pH level. pH level of seawater depends on the environmental conditions and tends not to change significantly.&#x0D; Keyword: Artificial Seawater, Brass, Corrosion Rat, pH, Salinity.

Study on preparation process and seawater corrosion resisting properties of chopped CF/PEEK composites

CF/PEEK composite material is widely used in marine engineering construction due to its characteristics of lightweight, high strength, corrosion resistance, and aging resistance, and it will inevitably produce side materials and wastes in the forming process. Therefore, the research on CF/PEEK recycling is of great significance. Due to the characteristics of PEEK’s high melting point and high viscosity of the solution, it is difficult to recycle and reuse such materials. In this paper, a certain amount of PEEK resin powder is added to improve the hot pressing technology of the chopped prepreg. Through a simulated seawater corrosion experiment, the influence of simulated seawater corrosion on the microstructure and mechanical properties of the composite materials is studied. Combined with the principal component analysis method, the corrosion resistance of the chopped CF /PEEK composite was evaluated comprehensively, which provided a reference for the recycling of thermoplastic prepreg and thermoplastic composite products. The results show that the surface quality and mechanical properties of the composites with resin powder are obviously improved. The resin matrix on the surface of the sample was subjected to salt corrosion by chloride ions in a simulated seawater solution to form local corrosion, resulting in pores, cracks, and other defects. The longer the corrosion time of simulated seawater is, the more serious the surface damage of the composite material is, and the more obviously the mechanical property declines. Principal component analysis showed that the resin content had little effect on the seawater corrosion resistance of chopped CF/PEEK composite.

Passivity study of titanium alloy TA2 in simulated seawater solution

In the present work, we introduced a novel way to study the Tafel slope of titanium in passive state based on potentiodynamic test with a break by potentiostatic polarization. The power law model as well as surface analysis methods such as AES and XPS were also introduced to character the thickness and composition of the film. Results indicate that the Tafel slope of titanium electrode in the passive state increases with the applied overpotential. The anodizing constant is found to be equal to about 0.24–0.46 Å/s and 4–10 Å/V. The results showing highly consistent with AES and XPS results. The passive film are mainly composed of TiO2 predominantly outer layer, and titanium sub-oxide, Ti(OH)x predominantly inner layer.

Interface-induced phase engineering to boost intrinsic catalytic activity of nickel selenide for improved water/seawater hydrogen evolution

Regulating electronic structure can fundamentally and effectively change the electrocatalytic HER performance of nickel selenide. Herein, we designed a highly-active electrocatalyst of interface-rich 1 T-MoSe2/NiSe via the interface-induced phase transition method from NiSe2 to NiSe. As expected, 1 T-MoSe2/NiSe showed superior HER performance in alkaline and alkaline seawater solution, which only required 98 and 104 mV at 10 mA·cm−2. Experimental and theoretical data displayed that the formation of heterointerface and phase transition in 1 T-MoSe2/NiSe could effectively regulate the phase structure and hydrogen adsorption energy in nickel selenide, thus improving the catalytic performance. Meanwhile, an abundance of specific surface area in 1 T-MoSe2/NiSe could allow reactants to easily arrive the active site and produce high electrocatalytic performance. In all, this work can offer a new vision for the designing highly-efficient nickel selenide-based electrocatalysts via the interface-induced phase engineering strategy.

Inhibition of membrane fouling by frequency agility electric field in desalination

In order to address the issue of RO membrane fouling in desalination, this research provides a technique for reducing RO membrane fouling by employing a frequency agility electric field. In this paper, a frequency agility electric field device is applied. The delta type underdamped damping oscillating signal with high speed random variation in frequency range of 80–300 kHz is developed. The signals were applied to a circulation experimental system which simulated seawater solution as working medium. The quality parameters and separation properties of RO membrane permeant and the morphology of scale on the membrane surface were analyzed experimentally. In this process, the energy consumption of the device is 3 W, and no wear will be caused to the permeable membrane during this process. The results show that under the condition of using electric field device, the salt rejection and flux of the membrane are increased by 15% and 35% respectively, the conductivity values and total dissolved solids(TDS) values of the permeate are decreased by 25% and 20% respectively, and the membrane pressure is reduced by 25%. In addition, the thickness of the crystals attached to the surface of the membrane is reduced, and the crystal clusters become smaller and sparser. The frequency agility electric field can effectively inhibit membrane fouling in desalination.

Reductive sorption of vanadium by green rust in seawater

Vanadium (V) is a redox-sensitive trace metal that typically exists in one of three oxidation states (+3, +4 and +5) in natural waters; a feature increasingly used in paleoredox studies of ancient marine sediments. However, our knowledge of V geochemistry in low-oxygen marine environments is still limited, especially regarding interactions of V with reduced iron minerals such as green rust. Carbonate green rusts (GRCO3) are mixed FeII/FeIII-phases found in some modern ferruginous settings, such as Lake Matano (Indonesia), and were likely abundant in ancient ferruginous marine systems where they may have played an essential role in authigenic V enrichments in sediments. Here, we present an abiotic pathway of V removal from seawater via reduction and adsorption onto amorphous GRCO3. Suspensions of the freshly precipitated GRCO3 (1 g L−1) were added to vanadate (1 mg VV L−1 initial concentration) in anoxic synthetic seawater solutions. Vanadium removal by GRCO3 was rapid and efficient, with 92 – 99% of V removed in under 20 seconds. Synchrotron-based X-ray absorption near edge structure (XANES) spectroscopy showed that VV adsorbed by GRCO3 was partially reduced to a mixture of VV and VIV, with the average oxidation state of adsorbed V increasing (+4.3 to +4.7) with increasing solution pH (7.5 to 8.5). Upon subsequent exposure to aerated seawater, V-bearing GRCO3 oxidized to lepidocrocite [γ–FeO(OH)] within 24 h, with concomitant reduction of all solid-phase VV to VIV. During oxidation, V was not released back into solution; rather, extended X-ray absorption fine structure (EXAFS) modeling revealed that VIV was structurally incorporated into lepidocrocite as octahedral vanadyl (VO2+). Our work further constrains the aqueous geochemistry of V, which has implications for understanding V cycling and removal mechanisms in both modern and ancient marine systems.

Experimental and theoretical assessments of the chamomile flower extract as a green corrosion inhibitor for aluminum in artificial seawater

The anticorrosive qualities of a number of natural items have been researched because of the growing concern regarding the environmental contamination produced by conventional corrosion inhibitors. Through electrochemical measurements, the current study evaluated the effectiveness of chamomile flower extract (CFE) in preventing the corrosion of aluminum in an artificial seawater solution. Atomic force microscopy (AFM) and scanning electronic microscopy (SEM) were used for surface examination. Utilizing FTIR, the chemical composition of CFE extract was investigated. Density functional theory (DFT) computations were used to conduct theoretical analyses of its main constituents. According to the electrochemical tests, corrosion inhibition increased as inhibitor concentration increased and reached a moderate inhibition efficiency of 75.66% at 20 mL/L. Polarization curves showed that CFE molecules behaved as mixed-type inhibitors and that their adsorption process primarily followed the Freundlich isotherm. Examination of the corroded aluminum surface by SEM and AFM confirmed the adsorption of compounds present in the extract. The main constituents of the natural extract's electronic characteristics were determined using chemical quantum calculations, which also clarified interactions between inhibitors and metal surfaces as well as adsorption modalities.

Impact of Reactive Oxygen Species Scavenging on the Intermediate Production of Anthracene and Anthraquinone in Fresh versus Saltwater Environments.

While salinity can alter the photodegradation of hydrophobic organic compounds (HOCs), the cause of their altered kinetics in seawater is not well understood. Because HOC intermediate photoproducts are often more toxic than their parent compounds, characterizing the generation of intermediates in saline environments is needed to accurately predict their health effects. The present study investigated the influence of salinity on the generation of anthraquinone through the photolysis of anthracene and the generation of anthrone and 1-hydroxyanthraquinone from the photolysis of anthraquinone as well as their reactivities with hydroxyl radicals. This was conducted by measuring the photolysis rates of anthracene and anthraquinone and characterizing their product formation in buffered deionized water, artificial seawater, individual seawater halides (bromide, chloride, and iodide), dimethyl sulfoxide, furfuryl alcohol, and solutions of hydrogen peroxide. Salinity enhanced the persistence of anthraquinone by a factor >10 and altered its product formation, including the generation of the suspected carcinogen 1-hydroxyanthraquinone. In part, this was attributed to reactive oxygen species (ROS) scavenging by the seawater constituents chloride and bromide. In addition, anthraquinone and its hydroxylated products were found to be moderately to highly reactive with hydroxyl radicals, further illustrating their tendency to react with ROS in aqueous environments. The present study emphasizes the importance of considering the effects of salinity on organic contaminant degradation; it can significantly enhance the persistence of HOCs and alter their intermediate formation, subsequently impacting chemical exposure times and potential toxic effects on estuarine/marine organisms. Environ Toxicol Chem 2023;42:1721-1729. © 2023 SETAC.

A Hypertonic Seawater Nasal Irrigation Solution Containing Algal and Herbal Natural Ingredients Reduces Viral Load and SARS-CoV-2 Detection Time in the Nasal Cavity.

Nasal irrigation is thought to decrease the viral load present in the nasal cavity. Our aim was to assess the effect of a hypertonic seawater solution [with algal and herbal natural ingredients (Sinomarin®)] on the viral load of nasopharynx in patients hospitalized with severe COVID-19 pneumonia. We conducted a prospective, randomized, controlled trial from June 2022 to December 2022. We allocated 56 patients with COVID-19 pneumonia into two groups (28 in each group)-the hypertonic seawater group [nasal irrigations with a hypertonic seawater solution (Sinomarin®) every 4 h for 16 h per day, for two consecutive days] and the control group (no nasal irrigations). A second nasopharyngeal swab was collected 48 h after the baseline nasopharyngeal swab (8 h after the last wash in the hypertonic seawater group) to estimate the SARS-CoV-2 viral load as determined by cycle threshold (Ct) values. In the hypertonic seawater group, the mean Ct values significantly increased two days after the initial measurement [ΔCt 48-0 h = 3.86 ± 3.03 cycles, p < 0.001 (95%CI: 2.69 to 5.04)]. No significant differences in the Ct values were observed in the control group [ΔCt 48-0 h = -0.14 ± 4.29, p = 0.866 (95%CI: -1.80 to -1.52)]. At follow-up, 17 patients from the hypertonic seawater group had negative test results compared to only 9 patients from the control group (p = 0.03). Nasal irrigations with a hypertonic seawater solution containing algal and herbal natural ingredients significantly decreased nasopharyngeal viral load and the detection time of SARS-CoV-2 in the nasal cavity.

Construction novel polybenzoxazine coatings exhibiting corrosion protection of mild steel at different concentrations in a seawater solution

In this work, a new and effective polymeric coating is used to improve mild steel's corrosion resistance. The coating incorporates a Schiff base moiety into a benzoxazine (BZ) precursor, resulting in improved protection against corrosion. The SF-Tol-BZ polymerization behavior and thermal properties were studied using differential scanning calorimetry (DSC) and thermalgravimetric analysis (TGA), respectively, at different curing temperatures. The poly(SF-Tol-BZ) cured at 240 °C had a Td10 value of 604 °C and a Tg of 225 °C. The efficacy of poly(SF-Tol-BZ) coatings in protecting mild steel (MS) from corrosion in a NaCl (3.5%) solution at room temperature was evaluated using various corrosion measurements, including open circuit potential (OCP), and electrochemical impedance spectroscopy (EIS). The results showed that increasing the poly(SF-Tol-BZ) concentration led to a corresponding increase in its protective efficiency, reaching a maximum of 92% at a concentration of 300 g/L. The coatings also exhibited a 24-fold increase in Rct values and a one-order-of-magnitude reduction in CPE compared to the bare mild steel. Finally, the poly(SF-Tol-BZ) precursors demonstrated a CO2 uptake of 23 mg g−1 (measured at 298 K).

Carbon nanocages confined multicomponent phosphide heterostructures for boosting oxygen evolution reaction in alkaline water and seawater

Transition metal phosphides (TMPs) have appealed tremendous interests in electrocatalytic oxygen evolution reaction (OER) due to its high intrinsic activity. Nevertheless, the poor electrochemical stability in harsh condition has seriously impeded their widespread application. Herein, we develop a facile strategy for realizing the substantial improvement in OER activity and stability by simultaneously engineering multicomponent phosphide heterostructure and introducing functionalized carbon nanocages. Profiting from the synergy of triple-phased heterostructure and the highly open hollow architecture, the MOF-derived Fe2P/Ni2P/NiCoP heterostructure functionalized carbon nanocages (FeNiCoP@CNC) presents a favorable catalytic performance towards OER in 1 M KOH and alkaline seawater solutions with the low overpotentials of 237 and 245 mV at 10 mA cm−2, respectively, and no significant degradation is observed over long-term stability testing of 40 h. Detailed mechanism studies demonstrate that the triple-phased phosphide interface can facilitate the electron transfer and provide more catalytic active sites, while the functionalized carbon nanocages also boost the mass transfer and protect the FeNiCoP nanoparticles from aggregation.

Bond durability performance of sand-coated BFRP bars in high-strength fiber reinforced concrete

The ever-increasing utilization of fiber-reinforced polymer (FRP) bars has led to a surge in research regarding their bonding properties with concrete. In this study, the bond durability behavior between high-strength fiber-reinforced concrete (FRC) and sand-coated basalt FRP (BFRP) bars was examined under three different environmental conditions including immersion in seawater solution at 50 °C for 3, 6, and 9 months, immersion in the sulfuric acid solution for 3, 6, and 9 months with an ambient temperature range of 20 to 30 °C, and exposure to 270 freeze–thaw cycles. A total of 60 pull-out samples were prepared using either basalt (B) fibers or polypropylene (PP) fibers. Plain concrete pull-out samples were served as controls. Test results revealed that all exposures have degraded the bond, leading to pull-out failure in all of the specimens. Exposure to 50 °C seawater was found to cause the most significant degradation. However, the use of basalt fibers helped to mitigate the loss of bond strength in the specimens when compared to plain concrete specimens. For example, after 3, 6, and 9 months of exposure to 50 °C seawater, bond strength retentions of 73.58%, 56.04%, and 34.47% were observed for basalt FRC (BFRC) specimens, compared to 39.64%, 49.37%, and 29.61% for plain concrete specimens. On the other hand, a lower retention in bond strength of 16.28% was recorded for polypropylene FRC (PPFRC) specimens at 9 months of exposure to 50 °C seawater. The bond stress-slip relationship of the tested bars was accurately predicted using two calibrated analytical models: the Eligehausen, Popov, and Bertero (BPE) model and the Cosenza, Manfredi, and Realfonzo (CMR) model. Notably, both models showed a strong correlation with the observed bond stress-slip relationships in the experiments.

Adsorption of Sodium Ion (Na+) onto Synthesized Zeolite-A from Malaysian Kaolin by Hydrothermal Method: Equilibrium and Kinetic Studies

Batch adsorption of sodium ion (Na+) using Malaysian kaolin-based materials, zeolite A was studied and observed. The experiments were done at different parameters such as varying initial concentrations of sodium ions in seawater solution (70 to 280 mg L–1), pH range of 6 to 8 and various adsorbent dosages (0.1 to 0.4g). The Langmuir and Freundlich's isotherms were used to analyse the data, and the results were compared. This study discovered that the Langmuir isotherm matched the experimental data very well, with the maximum monolayer adsorption capacities derived from the Langmuir equation being 769.3 mg g–1. Using pseudo-first-order, pseudo-second order, and intraparticle diffusion models, the kinetics of the reaction were further investigated and understood. The Intra Particle Diffusion Kinetic Equation was the most accurate description of the adsorption kinetics of sodium ions onto zeolite synthesis.

Corrosion Resistance of CeO2-GO/Epoxy Nanocomposite Coating in Simulated Seawater and Concrete Pore Solutions.

Reinforced concrete structures in the marine environment face serious corrosion risks. Coating protection and adding corrosion inhibitors are the most economical and effective methods. In this study, a nano-composite anti-corrosion filler with a mass ratio of CeO2:GO = 4:1 was prepared by hydrothermally growing cerium oxide on the surface of graphene oxide. The filler was mixed with pure epoxy resin at a mass fraction of 0.5% to prepare a nano-composite epoxy coating. The basic properties of the prepared coating were evaluated from the aspects of surface hardness, adhesion grade, and anti-corrosion performance on Q235 low carbon steel subjected to simulated seawater and simulated concrete pore solutions. Results showed that after 90 days of service, the corrosion current density of the nanocomposite coating mixed with corrosion inhibitor was the lowest (Icorr = 1.001 × 10-9 A/cm2), and the protection efficiency was up to 99.92%. This study provides a theoretical foundation for solving the corrosion problem of Q235 low carbon steel in the marine environment.