Calculation Of Isotherms Research Articles

Eco-friendly Chlorella vulgaris extracts for corrosion protection of steel in acidic environments

This study evaluates the potential of Chlorella vulgaris sp. extracts as eco-friendly corrosion inhibitors for API 5L 42 Steel in a 1M HCl acidic environment, offering sustainable alternatives for industrial applications. Two corrosion inhibitors were obtained through solvent extraction methods: M1 (methanol) and M2 (methanol/chloroform). The extracts were characterized using infrared spectroscopy, the analysis revealed hydroxyl, methyl and vinyl groups as the most representative. The effect of corrosion inhibition was study by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results show significant reductions in corrosion current density and increases in charge transfer resistance, with M2 achieving the highest protection efficiency of 91.20 % and a charge transfer resistance of 501.80 Ω at a 120 ppm concentration, while M1 reached 88.22 % efficiency with a charge transfer resistance of 102.30 Ω. Uv–Vis measurements were performed to determine the electronic transitions of the metal-inhibitor system for each of the extracts. ANOVA highlighted the significant influence of biomass concentration on corrosion resistance. The adsorption of M1 and M2 extracts on the carbon steel surface obeyed the Langmuir isotherm and Gibbs free energy calculations indicated a physisorption mechanism for both extracts. Surface morphology analysis by Scanning electron microscope (SEM) revealed less pitting and reduced surface roughness as inhibitor concentration increased. These findings underscore the potential of Chlorella vulgaris extracts, particularly M2 at 120 ppm, as effective and sustainable corrosion inhibitors for steel in acidic environments.

Graphene-based nanomaterials for adsorption of iodinated X-ray contrast media from contaminated water: A comparative study

Iodinated X-ray contrast media (ICM) was frequently detected in the aqueous environment. In this work, the applicability of three graphene-based nanomaterials (graphene nanosheets (GNS), graphene oxide (GO), and reduced graphene oxide (rGO)) for the adsorptive removal of the six ICMs including iohexol, iopamidol, iomeprol, iopromide, iodixanol and ioversol from aqueous solution was firstly evaluated by batch adsorption method. Among the three graphene-based nanomaterials, the GNS displayed the best adsorption performances for the adsorption of the six ICMs. The maximum uptakes of the six ICMs by the GNS (161.5 mg g−1 for iohexol, 267.2 mg g−1 for iodixanol, 197.7 mg g−1 for iopromide, 197.0 mg g−1 for iopamidol, 109.6 mg g−1 for iomeprol, and 168.2 mg g−1 for ioversol) can rapidly achieved within 10 min and indicate no dependence on pH in the range of 4–9. The results obtained from the calculations of isotherms, kinetics and thermodynamic supported the occurrence of a chemisorption of the GNS for the six ICMs. The π-π interactions between benzene ring of the ICMs and the sp2-hybridized two-dimensional sheet of GNS were deemed the predominant adsorption mechanism.

Preparation of cholesterol-imprinted polymer for selective adsorption of cholesterol from gastrointestinal mimicking solution.

The purpose of this study is to synthesize a highly selective adsorbent to remove cholesterol, one of the most important causes of cardiovascular diseases, from the intestinal mimic solution (IMS). For this purpose, cholesterol imprinted polymers were synthesized by suspension polymerization method using the molecular imprinting technique. In the first step, the functional monomer MATyr with hydrophobic character was synthesized. Then, the cholesterol-MATyr monomer precomplex was formed and the polymerization process was carried out by adding cross-linkers with the comonomer HEMA. The synthesized polymer poly(2-hydroxyethyl methacrylate-N-methacryloyl-(L)-tyrosine methylester) poly(HEMA-MATyr) was characterized by FTIR and SEM. The cholesterol adsorbing behavior of the synthesized poly(HEMA-MATyr) microbeads adsorbent was investigated at different initial concentrations, different temperatures, and adsorption times. The maximum adsorption capacity of microbeads was determined as 56.67 mg/g at a concentration of 2.5 mg/L. The amount of cholesterol adsorbed in the IMS was found as 83.07 mg/g polymer, which indicates that 92% of the cholesterol in the medium was adsorbed. The selectivity behavior of the cholesterol imprinted polymer was carried out with the stigmasterol and estradiol molecules, which are similar in structure, molecular weight, and character to the cholesterol molecule. The chol-imprinted polymeric beads were 21.38 and 10.08 fold more selective for cholesterol compared to estradiol and stigmasterol steroids used as competitor agents respectively. Kinetic and isotherm calculations of the synthesized cholesterol imprinted polymer were made and reusability experiments were carried out.

Calculation of hydrogen adsorption isotherms and Henry coefficients with mixed CO2 and CH4 gases on hydroxylated quartz surface: Implications to hydrogen geo-storage

Hydrogen is a clean fuel that is becoming increasingly popular in addressing future energy challenges, however, its viable storage requires an understanding of its interaction with underground rock minerals. For this purpose, this study focuses on developing adsorption isotherms and Henry coefficients for hydrogen in hydroxylated quartz surfaces, which are predominant in sandstone and shale rocks. In this study, a molecular-scale hydroxylated quartz structure with a pore space is generated and the Monte Carlo (MC) simulation is utilized to assess the adsorption isotherms and Henry coefficients. Initially, the CO2 adsorption with the hydroxylated quartz is matched with the published data to determine the accuracy of MC simulation and the mineral-fluid interaction. After that, the concentration of H2 within the pore is progressively increased and the competitive adsorption is calculated under various subsurface temperature and pressure conditions. Additionally, CH4 is introduced to understand the competitive adsorption dynamics between H2 and CH4. The findings indicate that increasing pressure results in increasing molecules of hydrogen that monotonically increase H2 adsorption. On the contrary, increasing temperature reduces the affinity of hydrogen with the quartz surface causing a decrease in adsorption capacity and Henry coefficients. Furthermore, a weak single hydrogen adsorption layer is developed at all pressure and temperature conditions, while most of the hydrogen remains as a free gas in the pore. In addition, the hydroxyl group controls most of the adsorption of hydrogen in the hydroxylated quartz. Furthermore, the addition of water film (approximately 1 wt%) reduces the hydrogen adsorption by around 3 %. The H2 adsorption values further experience a notable decrease with the introduction of CO2 and CH4, primarily due to the establishment of a strong adsorption layer caused by the high electrostatic attraction between these gases and the quartz mineral. The study offers crucial microscopic details regarding H2 adsorption alongside CO2 and CH4 gases within hydroxylated quartz pores. These insights support efficient hydrogen geo-storage and larger-scale simulation research.

Pore Structure Compartmentalization for Advanced Characterization of Metal-Organic Framework Materials.

Metal-organic frameworks (MOFs) are nanoporous crystals which are widely used as selective adsorbents, separation membranes, catalysts, gas and energy storage media, and drug delivery vehicles. The unique adsorption and transport properties of MOFs are determined by their complex three-dimensional (3D) networks of pores, cages, and channels that differ in size, shape, and chemical composition. While the morphological structure of MOF crystals is known, practical MOF materials are rarely ideal crystals. They contain secondary phases, binders, residual chemicals, and various types of defects. It is of paramount importance to evaluate the degree of crystallinity and accessibility of different pore compartments to adsorb guest molecules. To this end, we recently suggested the method of fingerprint isotherms based on the comparison of the experimentally measured adsorption isotherms and theoretical isotherms on ideal MOF crystals produced by Monte Carlo (MC) simulations and decomposed with respect to different pore compartments [Parashar, S. ACS Appl. Nano Mater. 2021, 4, 5531-5540 and Dantas, S.; Neimark, A. V. ACS Appl. Mater. Interfaces 2020, 12, 15595-15605]. In this work, we develop an automated algorithm for pore network compartmentalization that is a prerequisite for calculations of the fingerprint isotherms. The proposed algorithm partitions the unit cell into realistically shaped compartments based on the geometric pore size distribution. The proposed method is demonstrated on several characteristic systems, including Cu-BTC, IRMOF-1, UiO-66, PCN-224, ZIF-412, and 56 structures from the CoRE MOF database.

Smart pillar[5]arene-based PDMAEMA/PES beads for selective dye pollutants removal: design, synthesis, chemical-physical characterization, and adsorption kinetic studies.

This article reports on the synthesis of an innovative smart polymer, P5-QPDMAEMA, opportunely developed with the aim of combining the responsiveness of PDMAEMA polymer and the host-guest properties of covalently linked pillar[5]arenes. Thanks to a traditional Non-Induced Phase Separation (NIPS) process performed at various coagulation pH, the blending of P5-QPDMAEMA with polyethersulfone gave rise to the formation of functional beads for the removal of organic dyes in water. Adsorption tests are carried out on all the produced blend-based beads by employing two representative dyes, the cationic methylene blue (MB), and the anionic methyl orange (MO). In particular, the P5-QPDMAEMA based beads, prepared at acidic pH, featured the best MO removal rate (i. e., 91.3 % after 150 minutes starting from a 20 mg ⋅ L-1 solution) and a high selectivity towards the removal of the selected anionic dye. Based on the adsorption kinetics and isotherm calculations, the pseudo-first order and Freundlich models were shown to be the most suitable to describe the MO adsorption behavior, achieving a maximum adsorption capacity of 21.54 mg ⋅ g-1. Furthermore, zwitterionic beads are obtained by a post-functionalization of the PDMAEMA and the P5-QPDMAEMA based beads, to test their removal capability towards both anionic and cationic dyes, as shown.

Antibacterial and anticorrosion effects of Cetylpyridinium Chloride against Desulfovibrio desulfuricans biofilm and X80 steel corrosion

In this work, corrosion inhibition of X80 steel caused by Cetylpyridinium Chloride (CPC) in the presence of sulfate-reducing bacteria (SRB) was studied. The results showed that SRB accelerated the steel corrosion, whereas CPC had a good antibacterial activity against SRB corrosion. The growth of SRB was significantly inhibited with CPC concentration 10 mg L–1. The addition of 80 mg L–1 reduced the corrosion rate by 80 % in the presence of SRB. Molecular dynamics simulation and adsorption isotherm calculation showed that CPC can be adsorbed on the steel surface to form a protective film to protect steel form corrosion.

Capacity and kinetics of zearalenone adsorption by Geotrichum candidum LG-8 and its dried fragments in solution.

The application of LG-8 and its dry fragments as zearalenone (ZEN) adsorbents was investigated. The study showed that Geotrichum candidum LG-8 and its fragments dried at 55°C or through lyophilization are able to adsorb around 80% of ZEN. However, besides in water and 55°C-drying conditions, SEM indicated that higher 90% of ZEN binding tended to occur when cell walls of fragments were intact with less adhesion among themselves. Notably, ZEN/LG-8 fragments complexes were quite stable, as only 1.262% and 1.969% of ZEN were released after successive pH treatments for 4 h and 5 min. The kinetic data signified that adsorption of ZEN onto LG-8 fragments followed well the pseudo-first-order kinetic model. Isotherm calculations showed Langmuir model was favourable and monolayer adsorption of ZEN occurred at functional binding sites on fragments surface. Therefore, we conclude that it can be an alternative biosorbent to treat water contained with ZEN, since LG-8 is low-cost biomass and its fragments have a considerable high biosorption capacity avoiding impacting final product quality and immunodeficient patients.

The adsorption of naproxen on adsorbents obtained from pepper stalk extract by green synthesis

Abstract This study presented the adsorption of naproxen on adsorbents filled with Cu, Fe, and Cu/Fe nanoparticles (NPs) obtained by the green synthesis method from pepper stem waste. The resulting adsorbents were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy, and thermal gravimetric-differential thermal analysis. The amount of naproxen not adsorbed in the solution was determined from the cyclic voltammetry method, which is one of the electrochemical methods. The equation of the calibration curve used in the conversion of current to concentration and the R 2 value were y = 2.6165 x − 288.22 y=2.6165x-288.22 and 0.999, respectively. While the adsorption with the BS-extract was 3.3%, it was 46.142% for Cu-NP, 92 mg/g, and 57.622% for Fe-NP. With 116.0 mg/g Cu/Fe-NP, 82.406% and 165.0 mg/g capacity were reached. In the isotherm calculations, since the R 2 values for each adsorbent were in the range of 0.998–0.997, it was determined that the Freundlich and Halsey isotherms were compatible. Accordingly, under these conditions, Naproxen adsorption was multilayered and the adsorbent surface had a heterogeneous structure. Graphs drawn from the kinetic data showed that the adsorption obeyed the second-order kinetics. The R 2 value of the kinetic curves was 1 for all adsorbents. Thermodynamic data were determined by Van’t Hoff curves with R 2 values in the range of 0.998–0.996. The enthalpy value for Cu/Fe-NP was calculated to be 31.854 kJ/mol, the entropy value was 0.1993 kJ/mol-K, and the free energy was −27.5374 kJ/mol. These values were 34.605 kJ/mol, 0.272 kJ/mol-K, and −46.451 kJ/mol for Fe-NP, respectively; and 19.79 kJ/mol, 0.247 kJ/mol-K, and −54.3226 kJ/mol for Cu-NP. While all NPs (except Cu-NP) had a high recovery percentage in three cycles, this decreased to 80% at pH 10. For Cu-NP, the recovery percentage decreased at pH 8.5 and 7, but surprisingly it increased at pH 10. As a result, it can be inferred that NPs play a good role in adsorbent development, and Fe and Cu NP-doped BS adsorbents have a better effect on naproxen adsorption and have been evaluated as adsorbents suitable for use several times.

Modified superhydrophobic magnetic Fe3O4 nanoparticles for removal of microplastics in liquid foods

Microplastics (MPs) stemming from plastic products have attracted wide attention around the world due to their stealth, persistence and potential threat to humans. It is essential to remove MPs by using eco-friendly and effective methods. In this study, to remove MPs, we proposed to prepare Fe3O4 superhydrophobic magnetic adsorbents (Fe3O4@Cn, n = 12, 14, 16, 18) modified by different saturated fatty acids (C12, C14, C16, C18) by liquid phase deposition method. Transmission electron microscope, atomic force microscopy, Fourier transform infrared spectroscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, vibrating sample magnetometry and nitrogen adsorption measurements were applied to characterize the morphology, functional groups, crystalline structures of Fe3O4@Cn as well as its magnetic properties and pore size distribution. It was shown that Fe3O4@Cn exhibited the characteristics of magnetic materials with superhydrophobic properties and thus possessed the ability to separate oil and water. During the removal of MPs in five liquid food systems, Fe3O4@C12 exhibited 92.89 % adsorption efficiency, which was ascribed to the electrostatic and chemical bonding interactions between MPs and Fe3O4@Cn, as suggested by density functional theory (DFT) calculations. In addition, the presence of organic matter in water can decrease the removal efficiency of Fe3O4@Cn due to the competitive adsorption effect. Simulation by Langmuir isotherm model suggested that Fe3O4@C12 displayed the greatest adsorption efficiency for Polystyrene (PS) (809.29 mg/g), which is higher than that of Fe3O4@C14, Fe3O4@C16, and Fe3O4@C18. In addition, Langmuir adsorption isotherm and Gaussian calculations suggested that PS was removed by Fe3O4@C12 through an exothermic reaction controlled by chemisorption. Overall, these results indicated that superhydrophobic magnetic materials prepared in this study show high potential for removing MPs in aqueous systems due to their low costs, good environmental friendliness, and high removal performance.

Isotherm and Thermodynamic Calculations of Adsorption Method for Removal of Crystalline Violet Dyestuffs from Wastewater Using Koçpınar/Siirt Clay

Araştırmamızda, kanserojen etkisi de bilinen boyar maddelerden biri olan kristal viyoletin sulu çözeltilerden Siirt/Koçpınar kili ile uzaklaştırılması çalışıldı. Birinci aşamada kil modifikasyona maruz bırakılmadan doğal şekliyle (KO) kullanıldı, ikinci aşamada ise aynı işlemler HNO3 ile aktifleştirilen Siirt/Koçpınar kili (KA) ile tekrar edildi. Adsorpsiyon neticesinde veriler D-R, Langmuir ve Freundlich izoterm modellerine uygulandı. Hesaplamalar sonucunda en iyi verim, 0.4 g adsorbent dozajı ile pH 5 ortamında elde edildi. Çalışma neticesinde optimum koşullarda KO adsorbenti için % 59.48, KA adsorbentin de % 83.97 giderim sağlandı. Korelasyon katsayısının 0.99’dan büyük olarak hesaplandığı Freundlich izoterm modeli, çalışmamızın uygun olduğu izoterm modeli oldu. Ayrıca D-R izoterm modeli için bulunan D-R adsorpsiyon serbest enerjisi, hem doğal hem de aktifleştirilmiş kil için 8 kJ/mol değerinden küçük bulundu. Bu sonuç adsorpsiyon işleminin fiziksel olduğunu gösterdi. Termodinamik hesaplamalar neticesinde hesaplanan Gibbs serbest enerji değerlerinin sıfırdan küçük çıkması bizlere çalışmamızın istemli meydana geldiğini gösterdi.

Application of Ionic Liquid Crosslinked Hydrogel for Removing Heavy Metal Ions from Water: Different Concentration Ranges with Different Adsorption Mechanisms.

Heavy metal wastewater poses a significant environmental challenge due to its harmful effect on organisms and difficult biodegradation. To address this issue, hydrogel has been used as a promising solution for the adsorption of heavy metal ions in water, offering advantages such as low cost, simple design, and environmental friendliness. In this study, we synthetized a novel poly-acrylamide/acrylic acid/vinyl imidazole bromide (PAM/AA/[Vim]Br2) hydrogel as an effective adsorbent for the removal of NiII, CuII, ZnII, and CrIII from water. The structure of the hydrogel was characterized by using techniques such as Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). By exploring various parameters such as monomer ratio, neutralization degree, crosslinking agent addition amount, and initiator addition amount, the highest swelling ratio of the PAM/AA/[Vim]Br2 hydrogel reached 40,012%. One of the notable aspects of this study lay in the investigation of the adsorption behavior of the hydrogel towards heavy metal ions at different concentrations. The adsorption isotherm calculations and X-ray photoelectron spectroscopy (XPS) analysis revealed distinct adsorption mechanisms. At low concentrations, the hydrogel exhibits a multilayer physical adsorption mechanism, with heavy metal ion removal rates exceeding 80%; while at high concentrations, it demonstrates a monolayer chemical adsorption mechanism, with heavy metal ion removal rates above 90%. This dual mechanism approach distinguishes our study from previous reports on the removal of heavy metal ions using hydrogels and shows good ion adsorption efficiency at both high and low concentrations. To the best of our knowledge, this is the first report to explore the removal of heavy metal ions from water using hydrogels with such intriguing dual mechanisms. Overall, the utilization of the PAM/PAA/[Vim]Br2 hydrogel as an adsorbent for heavy metal ion removal presents a promising and innovative approach, contributing to the development of environmentally friendly solutions for heavy metal wastewater treatment.

A study on the anti-corrosion mechanism of the eco-friendly inhibitor Ribavirin on Q235 steel in an acidic chloride environment

Developing efficient and eco-friendly corrosion inhibitors to replace traditional toxic and harmful ones is necessary for protecting the ecological environment. Herein, we have developed an eco-friendly drug corrosion inhibitor, Ribavirin (RBVR), which could effectively inhibit Q235 steel corrosion in 1 M HCl solution. EIS results showed that RBVR slowed down the corrosion rate of steel, and η could reach up to 97.7 % when the concentration of RBVR was only 10 mM. The potentiodynamic polarization curve results indicated that RBVR was a modest mixed-type corrosion inhibitor that could inhibit steel anodic and cathodic reactions. The adsorption isotherm and theoretical calculations revealed that the adsorption of RBVR on the steel surface was in the form of parallel adsorption, which maximized the protection of steel. The adsorption of RBVR molecules on the steel was mainly based on the N and O heteroatoms as the active adsorption centers. A monolayer protective film was formed on the steel surface, which retarded the dissolution of active sites. This work will provide a theoretical basis for developing novel, efficient, eco-friendly organic inhibitors and promoting their industrial application.

Temperature distribution in the crust and upper mantle of the territory of Ukraine

The study aims to build a three-dimensional thermal model of the crust and upper mantle of the territory of Ukraine. Its basis is a scheme of deep processes in the tectonosphere, which, first of all, considers the results of heat and mass transfer during modern activation. They are superimposed on the models of the platform (except for the territory of the East European platform; the Donbas is also included in it), the Alpine geosyncline of the Carpathians, and the Hercynian-Cimmerian geosyncline of the Scythian plate. The incomplete process of modern activation cannot be accurately described by the geological theory used by the authors. Gravity modeling was previously conducted on a system of profiles around the northern hemisphere with a total length of more than 30,000 km, crossing Eurasia, North America, as well as the Atlantic and Pacific oceans to select an adequate scheme of heat and mass transfer. The paper distinguishes the most realistic scheme of the process . It is applied for Ukraine, and the more accurately the activated area is determined. Such a task was solved for the first time. In the south, the model is limited by the Black Sea depression, at a depth of 400 km. Temperatures in the transition zone to the lower mantle were not considered. Test thermal models are compared with geothermometers. The error (50°C) of calculation and cross-section of isotherms is determined (150°C for depths from 50 to 400 km, at a depth of 25 km the error is lower, the cross-section of isotherms is 100°C). Zones of partial melting of the rocks of the crust and upper mantle have been established. They are distributed in the middle part of the crust, in the upper horizons of the mantle (50-100 km). At a depth of about 400 km, partial melting occurs only under the non-activated part of the platform. Differences in the model from the presented one are described. They are associated with possible variations in the age of the process and its peculiarities at different levels of heat and mass transfer. Practical significance. The study emphasizes that mineral deposits are characteristic to thermal anomalies and other environmental parameters.

A Zn-based metal coordination cluster Zn5 used for solid phase microextraction of ten phenolic compounds from water and soil

Exploring coating materials with superior extraction efficiency has always been the pursuit in the field of solid phase microextraction (SPME). Metal coordination clusters with high thermal and chemical stability, abundant functional groups as active adsorption site are the promising coatings. In the study, a Zn5(H2Ln)6(NO3)4 (Zn5, H3Ln =(1,2-bis-(benzo[d]imidazol-2-yl)-ethenol) cluster coating was prepared and applied for SPME of ten phenols. Zn5 based SPME fiber exhibited high extraction efficiencies for phenols in headspace (HS) mode, which circumvented the pollution of SPME fiber. The adsorption isotherm and theoretical calculation indicated the adsorption mechanism of phenols on Zn5 was hydrophobic interaction, H-bond interaction and π-π stacking. Under the optimized extraction conditions, an HS-SPME-GC-MS/MS method was developed for the determination of ten phenols in water and soil samples. For ten phenolic compounds in water and soil samples, the linear ranges were 0.5–5000 ng/L and 0.5–250 ng/g, respectively. The limits of detection (LODs, S/N = 3) were 0.010–1.20 ng/L and 0.0048–0.16 ng/g, respectively. The precisions of single fiber and fiber-to-fiber were lower than 9.0% and 14.1%, respectively. The proposed method was applied for the detection of ten phenolic compounds in various water and soil samples, showing satisfactory recovery (72.1–118.8%). This study delivered a novel and efficient SPME coating material for the extraction of phenols.

Surface Properties and Molar Volumes of Acetone–Ethanol Solutions

Experimental data are presented on the surface tension and density of acetone (chemically pure) and ethanol (pure for analysis) and acetone–ethanol solutions of different concentrations. The temperature dependence of density is measured with a VIP-2MR vibration density meter with a systemic error of ±0.01 g/cm3. Surface tension (ST) is measured with hanging drops on a DSA-100 KRUSS tensiometer whose systemic error is no more than 1%. Experimental measurements show the concentration dependences of molar volumes and surface tension within the experimental error are described by a linear function. Calculations of the ST isotherms according to the equation of A.A. Zhukhovitsky, obtained by assuming the surface layer and bulk phase are ideal, show the theoretical ST isotherms coincide with experimental ones within the experimental error. Calculations of the thermodynamic parameters of the surface layer show the coefficients of thermodynamic activities of the components in the surface layer are close to unity throughout the range of concentrations. Based on these results and the finite thickness of layers, it is concluded that the surface layers of ethanol–acetone solutions is ideal.

The Role of Diethanolamine on Chemical Mechanical Polishing in Alkaline Glycine-Based Slurries for Cobalt Interconnects

Cobalt (Co) and its low resistivity, superior adhesion property, and void-free seamless fill ability, pledge to transform the landscape of integrated circuits in many areas, especially in interconnects and logic contacts. Chemical mechanical polishing (CMP), which can realize local and global planarization, has been recognized as one of the indispensable manufacturing approaches for the fabrication of multilevel metal interconnection structures. The present work introduces diethanolamine (DEA) into our alkaline glycine-based slurries for Co CMP process. The action mechanism of DEA on Co CMP process in glycine-based slurries at pH 8.1 has been clearly revealed by various approaches, including polishing and static etching experiments, X-ray photoelectron spectroscopy survey, electrochemical analysis, as well as adsorption isotherm calculation. At low concentrations, DEA could be able to accelerate the polishing process via its auxiliary complexing effect, obtaining higher removal rates and larger corrosion current densities. Some pitting corrosion could appear on Co surfaces due to the production of Co-glycine complex as well as the auxiliary complexing process, making rougher surface qualities. On the other hand, when the DEA concentration increased to a certain level, it could play a role of corrosion inhibitor, protecting Co surfaces by forming a stable passive layer and moderating material removal rates, removal selectivity, and surface roughness.

A novel green corrosion inhibitor extracted from waste feverfew root for carbon steel in H2SO4 solution

The extract of waste feverfew root (FRE) is firstly used as green corrosion inhibitors for carbon steel in H2SO4 solution. Weight loss method and electrochemical tests are carried out to evaluate the corrosion inhibition efficiency. The in-situ scanning vibrating electrode technique is applied to monitor the inhibitive behavior of corrosion inhibitor. Water contact angle, scanning electron micrograph and X-ray photoelectron spectroscopy are used to characterize the compositions and microstructure of corrosion products. Results indicate that the optimum corrosion inhibition can reach 98.1% at 400 mg/L, and it can retain above 91% after immersion for 96 h. Based on the adsorption isotherm calculation, FRE and KI obey to Langmuir adsorption model. The adsorption film possesses hydrophobicity and can effectively retard the evasion of corrosive media.

Characterization and dye adsorption effectiveness of activated carbon synthesized from olive pomace

Studies, about products obtained from agricultural wastes, have increased within the scope of zero waste studies . The olive pomace is produced as a result of olive oil production. In the present study, activated carbon was synthesized using the olive pomace taken from the olive pomace processing plant operating with a three-phase process. The synthesized activated carbon characterization was performed using Scanning Electron Microscope (SEM), Fourier-Transform Infrared Spectroscopy (FT-IR), Brunauer – Emmett – Teller (BET), and X-Ray Crystallography (XRD) devices. Olive pomace activated carbon (OPAC) was used for the adsorption of dye from an aqueous solution. The adsorption efficiency of the OPAC was investigated. The initial pH value of dye solution (6-9), the amount of activated carbon (0.5 and 1.0 g/L), and initial dye concentration (600-1200 mg/L) were optimized. Also, adsorption kinetic and isotherm calculations were evaluated. The optimum parameters were found as the original pH value (pH=8) of dye solutions, OPAC amount of 1.0 g/L and the initial concentration of 1000 mg/L. The Langmuir isotherm model and the pseudo-second-order kinetic model were found as the most suitable models. It can be said that the synthesized material can be used at dye removing from wastewater.

Synergistic effect of 1,2,4-triazole and phytic acid as inhibitors on copper film CMP for ruthenium - based copper interconnected and the surface action mechanism analysis

Ruthenium (Ru) has been selected as the next-generation barrier material for copper (Cu) interconnects due to its excellent electrical properties, high breakdown voltage, low leakage current, low resistivity and while improving the electromigration resistance of Cu interconnects. However, during the one-step chemical mechanical polishing (CMP) of Cu film, high removal rate of Cu and close to zero removal rate of Ru are required, which brings great difficulty to realize Cu film planarization. Inhibitors play a crucial role in controlling Cu and Ru removal rate and inhibiting the surface corrosion during the Cu films CMP. In this study, phytic acid as a green corrosion inhibitor was introduced in the Cu slurry and compared with 1,2,4-triazole (TAZ) as traditional inhibitor. From removal rate, static etch rate, surface quality and inhibition efficiency, it revealed that the corrosion inhibition of Cu and Ru by phytic acid was stronger than that of TAZ, while the obtained surface quality was weaker than that of TAZ. Through the analysis of UV–Visble spectroscopy and adsorption isotherm calculation, it revealed that the physical-chemical adsorption of both, which favored physical adsorption, existed on the Cu surface caused by weak van der Waals's forces. Therefore, in order to obtain dual physical-chemical adsorption and improve the passivation performance and inhibition efficiency, the mixture of both was adopted. The inhibition efficiency of Cu and Ru was increased to 53.7% and 66.4% compared with phytic acid alone, respectively. The static etch rate of Cu was dropped by 200 Å/min. The surface quality was significantly improved, and the roughness dropped to 1.64 nm. Through X-ray photoelectron spectroscopy analysis, it was showed that Cu-TAZ and Cu-phytic acid generated by the mixed inhibitor and Cu formed a double-layer physical-chemical adsorption film on the surface, which increased the coverage of adsorption sites and improved the inhibition efficiency. Finally, the stability test shows that the slurry can be stable for at least 7 days, which has theoretical guiding significance for the research and development of low-node Cu film slurry.