1M HCl Research Articles

Effect of HCl Concentration and Acetone Washing on the Dielectric and Conduction Properties of Polyaniline Salts

Background: In order to know the effect of acid concentration, comparative electrical properties of PANI salt samples prepared in two different media like water, 1M HCl and 2M HCl, have been studied. Methods: To know the effect of acetone washing on the electrical behavior of the polymer, the polymer samples were washed with acetone. The X-ray diffraction pattern shows a crystalline nature of all the prepared PANI salt samples except non-acetone washed PANI salt prepared in 2M HCl. The SEM micrograph suggests a uniform and continuous morphology for PANI salts prepared in 1M HCl, agglomerated granulated structure for PANI salts prepared in 1M HCL, and fiber type structure for PANI salts prepared in 2M HCl. Results: The study showed that the dielectric constant decreases with frequency in the case of all the synthesized polymer samples. The variation of AC conductivity of the synthesized polymer samples with respect to the frequency at room temperature follows the power law. Through the fitting parameters, the DC conductivity was found. Conclusion : The results showed that the polymer sample, which was prepared in water medium and not washed with acetone, had the highest dielectric and conductivity values, whereas for acetone washed samples highest dielectric and electrical conductivity was observed for the sample prepared in 2M HCl.

Synthesis, Characterization of New Polytriazole Derivatives from Polyacryloyl chloride and Theoretical with Corrosion Inhibitor Study for Stainless steel in acidic medium

The purpose of the study is to synthesize and characterize a new polytriazole derivative from polyacryloyl chloried, first reaction of polyacryloyl chloride with hydrazine hydrate in the presence of DMF as a solvent to obtained acid hydrazide (1) than reacted with different amide to give poly 1,2,4-triazole derivatives(1a-1c). Newly synthesized compounds were characterized by spectral methods [13C-NMR, 1H-NMR, and FTIR] and calculated some of its physical properties. Also, we worked theoretical study involving calculated the geometric configurations, total energy, dipole moment etc..,. In addition, the inhibition effect of the synthesized compounds (1a-1c) on corrosion of stainless steel in 1M HCl were studied by method of weight loss. The results of weight loss measurements showed that corrosion inhibition efficiency by increasing the concentration of organic inhibitors for stainless steel in 1M HCl solution at 30oC.

Corrosion Behaviour of High-Strength Al 7005 Alloy and Its Composites Reinforced with Industrial Waste-Based Fly Ash and Glass Fibre: Comparison of Stir Cast and Extrusion Conditions.

The stringent demand to develop lightweight materials with enhanced properties suitable for various engineering applications is the focus of this research work. Industrial wastes such as fly ash (FA) and S-glass-fibres (GF) were used as reinforcement materials for high-strength alloy, i.e., Al 7005. Stir casting routes were employed for fabricating the four samples, Al 7005, Al 7005 + 5% GF, Al 7005 + 6% FA and Al 7005 + 5% GF + 6% FA. The extrusion process with different extrusion ratios (ER: 5.32:1, and 2.66:1) was used to examine the properties of all four samples. Extruded samples with ER: 5.32: 1 resulted in equiaxed grains with refined structure compared to stir casting parts. The effect of the extrusion process and the addition of reinforcements (GF and FA) on the gravimetric, electrochemical, and electrochemical impedance corrosion behaviour of Al 7005 composites in 1M HCl (Hydrochloric acid) solution were investigated. The results of all three corrosion methods showed that Al 7005 + 6% FA exhibited higher corrosion resistance. Corrosion rate of Al 7005, Al 7005 + 5% GF, Al 7005 + 6% FA and Al 7005 + 5% GF + 6% FA is found equal to 3.25, 2.41, 0.34, and 0.76 mpy, respectively. The FA particles remain inert and act as a physical barrier with corrosive media during the corrosion test. GF undergoes fibre degradation or disrupts the continuity of the glass network as a result of fibre leaching, which increases the corrosion rate in the sample. The gravimetric study showed that the corrosion rates decreased with an increase in extrusion ratio, which might be due to corrosion passivation increases and improved properties. The scanning electron microscopy reveals that corrosion fits, flakes and micro-cracks were observed more in the as-cast composites than that of extrusion composites, promoting the corrosion rate.

Synergetic effect of the combination of Prosopis Farcta extract with sodium dodecyl sulfate on corrosion inhibition of St37 steel in 1M HCl medium

In this study, the inhibition effect of Prosopis farcta (PF) extract combined with Sodium Dodecyl Sulfate (SDS) on the corrosion of St37 steel in 1 M HCl was investigated by electrochemical tests (polarization and EIS) and surface examination (AFM and FESEM). The results of polarization tests showed that the critical micelle concentration (CMC) of SDS in 1 M HCl at ambient temperature is 400 mg/L. It was found that the combination of 800 mg/L PF extract and 400 mg/L SDS have a synergistic effect. The highest inhibition effect for St37 steel in 1 M HCl was 90%, which was achieved when 800 mg/L PF was combined with 400 mg/L SDS. The adsorption of this inhibitor follows the Langmuir isotherm.

Biochar-supported polyaniline hybrid for aqueous chromium and nitrate adsorption

Biochar adsorbents can remove environmental pollutants and the remediation of Cr(VI) and nitrate are considered. Cr(VI) is a proven carcinogen causing serious health issues in humans and nitrate induced eutrophication causes negative effect on aquatic systems around the world. Douglas fir biochar (DFBC), synthesized by fast pyrolysis during syn gas production, was treated with aniline. Then, a polyaniline biochar (PANIBC) composite containing 47 wt% PANI was prepared by precipitating PANI on DFBC surfaces by oxidative chemical polymerization of aniline in 2M HCl. PANIBC exhibited a point of zero charge (PZC) of 3.0 and 8.2 m2/g BET (N2) surface area. This modified biochar was characterized by thermogravimetric analysis (TGA), scanning electron microscopy (SEM) morphology and surface elements, and oxidation states by X-ray photoelectron spectroscopy (XPS). PANIBC exhibited positive surface charge below pH 3, making it an outstanding adsorbent, for Cr(VI) removal. Cr(VI) and nitrate removal mechanisms are presented based on XPS analysis. DFBC and PANIBC Cr(VI) and nitrate adsorption data were fitted to Langmuir and Freundlich isotherm models with maximum Langmuir adsorption capacities of 150 mg/g and 72 mg/g, respectively. Cr(VI) and nitrate removal at pH 2 and 6 were evaluated by reducing the amount of PANI (9 wt%) dispersed on to DFBC. Adsorption capacities verses temperature studies revealed that both Cr(VI) and nitrate adsorption are endothermic and thermodynamically favored. Regeneration studies were conducted on both DFBC and PANIBC using 0.1M NaOH and PANIBC exhibited excellent sorption capacities for Cr(VI) and nitrate in lake water samples and in the presence of competitive ions.

EVALUATIONS OF CORROSION INHIBITION OF MILD STEEL USING EXTRACT FROM CHROMOLAENA ODORATA(SAIM WEED) IN ACIDIC MEDIA

Determination of the corrosion inhibition of chromolaena odorata extract was carried out on mild steel at the different concentrations for 1M HCL and 0.5M H2SO4. The results show that the corrosion rate of mild steel increases with increasing temperature and decreases with an increase in the concentration of the extract. While the inhibitory effect of plant extract was more noticeable in 0.5M H2SO4than in 1M HCL even at higher concentrations. The observed trend in temperature and inhibition efficiency (1.E%) was because of the molecules of the extract absorbed on the surface of the mild steel as the concentrations increases.

PEMANFAATAN ARANG AKTIF KULIT JENGKOL (Pithecellobium lobatum) SEBAGAI ADSORBEN DALAM MENYISIHKAN KADAR COD DAN TSS PADA LIMBAH CAIR TAHU

Tofu liquid waste comes from the washing process, boiling, and printing on tofu production. Tofu liquid waste is usually directly discharged into rivers or sewers which can have a negative impact on the environment. Tofu wastewater treatment with activated charcoal adsorption methods can reduce the concentration of pollutants contained in the waste. This research was conducted to determine the effect of variations in stirring speed in the removal of COD and TSS levels in tofu liquid waste. The adsorbent used in this study was activated charcoal from the skin of jengkol (Pithecellobium lobatum) carbonized at 350ºC which was then activated using 1M HCL. The adsorption process in this study used a mass of 2 g of activated charcoal; 4 g, 6 g and 8 g and stirring speed 60 rpm and 120 rpm. The initial concentrations of COD and TSS were 5140 mg/L and 605 mg/L. The results of the research that have been carried out show that the stirring speed and mass of the adsorbent affect the levels of COD and TSS as well as the effectiveness and adsorption capacity. A significant decrease in COD and TSS levels occurred in the treatment using 8 g of activated charcoal and a stirring speed of 120 rpm. The COD value obtained was 1137 mg/L, TSS was 103 mg/L and the efficiency value obtained was COD of 77.88% and TSS of 82.98%.

Synthesis and Characterization of New poly β-Lactam from poly acrolein and Study Corrosion Inhibition for Stainless steel in Hydrochloric Acid Solution

A new poly chain derivative of polyacrolein has been synthesized from the two basic precursors, polyacrolein and aromatic amine/substituted amine in chloroform to prepare poly Schiff base compounds (A1-A4). The novel poly subs.β-lactam derivative is obtained via coupling of poly schiff base with chloroacetyl chloride and trimethylamine (B1-B4). Newly synthesized compound was identified via spectral methods; their [13C-NMR, 1H-NMR, and FTIR] also measurement of some of its physical properties. Furthermore the inhibition effect of synthesized compounds (B1-B4) on the corrosion of stainless steel in 1N HCl was studied by wight loss method. The results of weight loss measurements showed that corrosion inhibition efficiency by increasing the concentration of organic inhibitors for stainless steel in 1M HCl solution at 30°C.

Hidroklorik Asit çözeltisinde bizmut ilavesinin Sn – 3Ag – 0.5Cu lehim alaşımının korozyon dinamiklerine etkisi

This paper aims to investigate the effect of bismuth addition on the corrosion behaviour of Sn–3.0Ag–0.5Cu (SAC 305) solder alloy in 1M HCl acid solution under potentiodynamic polarization. After electrochemical tests, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to examine the properties of the samples. Polarization studies indicated that an addition of 0.5, 1, and 2 wt.% Bi in the SAC305 solder alloy doesn't lead to significantly different corrosion potentials. Instead of a true passivation region, a pseudo-passivation region is observed in which currents are nearly constant (though high). This pseudo-passive region does not have a reactivation point within the scanning interval. Corrosion rates, on the other hand, follow a pattern in which 1 wt.% bismuth replacement of silver causes a drop-in corrosion rate. With the further replacement of silver with bismuth, however, the corrosion rate increases. Microstructure analysis reveals the existence of gaps and porosities which introduce limits on the formation and stability of protective passive corrosion products.

The utilization of okra leaves as an agricultural waste for the removal of As(III) and As(V)

<p>In the present study the sorption efficiency of okra leave sorbent for As(III) and As(V) is demonstrated. Sorption reaction is pH and time dependent. The sorbent shows maximum removal of As(III) and As(V) at pH 7 and pH 6 respectively and equilibrium was achieved at 180 minutes. In isotherm study experimental data were explained by Freundlich and Flory-Huggins models. Maximum sorption capacities calculated by Freundlich Isotherm were 5672.0 μg g-1 and 13160 μg g-1 for As(III) and As(V) respectively. Psuedo-second order rate equation and Morris-Weber equation explained the kinetics of sorption reaction. Due to the presence of heterogeneous active sites on the sorbent, surface sorption as well as intra-particle diffusion occurred. Thermodynamically, sorption reaction was endothermic in nature and proceeded spontaneously. Desorption study revealed that 89.82% of As(III) and 97.11% of As(V) were removed with 1M HCl.</p>

Enhancing the Inhibition Effect and Adsorption Efficiency of Ethoxylated Dodecyl Alcohols on Corrosion of 316 Stainless Steels in 2M HCl

Enhancing the Inhibition Effect and Adsorption Efficiency of Ethoxylated Dodecyl Alcohols on Corrosion of 316 Stainless Steels in 2M HCl

Synthesis, Characterization and corrosion Inhibition Studies on Mn (II) and Co (II) Complexes Derived from 1-{(Z)-[(2-hydroxyphenyl) imino]methyl}naphthalen-2-ol in 1M HCl Solution

Schiff base derived from the reaction of 2-amino phenol and 2-hydroxy-1-naphthaldehyde and its Co (II), and Mn (II) complexes have been synthesized and characterized by solubility test, melting point/ decomposition temperatures, molar conductance, IR and magnetic susceptibility. The number of ligands coordinated to the metal ion was determined using Job’s method of continuous variation. Their molar conductance values indicate that all the complexes are non-electrolytes. Magnetic moment values of the complexes showed that both Mn (II) and Co (II) are paramagnetic. The spectroscopic data of metal complexes indicated that the metal ions are complexed with azomethine nitrogen and deprotonated oxygen atom. Corrosion inhibition of the schiff base and Mn (II) and Co (II) complexes were evaluated using the weight loss method in a 0.1MHCl solution for copper metal. The inhibition efficiency increased with increasing inhibitors concentration. The negative values of Gibb’s free energy of adsorption (ΔGads) confirmed the spontaneity and physical adsorption of the inhibition process which is inconsistent with Langmuir adsorption isotherm.

Theoretical and surface/electrochemical investigations of walnut fruit green husk extract as effective inhibitor for mild-steel corrosion in 1M HCl electrolyte

The present paper has studied the corrosion inhibition property of Juglone extracted from walnut (Juglans regia L.) green husk for mild steel samples exposed to an acid electrolyte (1 M HCl). Besides, via computer modelings, the attraction forces of the inhibitors/metal surface were explored. The corrosion inhibition efficiency of the organic inhibitor was evaluated using potentiodynamic polarization as well as EIS techniques. In addition, XPS, FT-IR, SEM, AFM, and UV–visible spectroscopy have been used to study the inhibition mechanism of the agricultural waste extract in the corrosive media. Quantum chemical calculations based on DFT theory and molecular dynamic simulations were investigated on the adsorbed Juglone inhibitors. The obtained results indicated that the efficiency of the used inhibitor was enhanced with increasing the concentration of green corrosion inhibitor (GCI) and reached 95% in the presence of 800 ppm after 8 h immersion. Moreover, the average roughness of the exposed metal to the corrosive electrolyte decreased from 68.2 ± 8.3 nm for the blank solution to 3.4 ± 0.3 nm for the solution containing 800 ppm GCI. Furthermore, the Tafel extrapolated polarization results revealed that the extracted GCI functioned as a mixed-type corrosion inhibitor. Finally, the obtained analysis results are supported by theoretical data.

Inhibition of acid corrosion in API 5L X52 steel with 1,2,3-triazole derivatized from benzyl alcohol: Experimental and theoretical studies

This work presents the synthesis of new triazoles derived from benzyl alcohol to be used as corrosion inhibitors for API 5L X52 steel in HCl 1M medium. The results showed that all derivatives displayed a better inhibitory capacity than benzyl alcohol. Electrochemical impedance spectroscopy in conjunction with polarization curves revealed that compound 6 showed the highest inhibitory capacity of all derivatives with 94.2% inhibition efficiency at a concentration of 50 ppm. Furthermore, it was determined that compounds 3, 6 and 7 were inhibitors with anodic behavior and compounds 4 and 5 acted as mixed inhibitors. Benzyl alcohol and all its synthesized derivatives fitted the Langmuir adsorption isotherm. The combined adsorption phenomenon was proposed according to the thermodynamic parameter values obtained. Dispersion-corrected DFT studies, assuming the cluster approach, obtained free binding energies that matched well with experimentally determined standard adsorption free energies. The mixed physisorption-chemisorption observed was explained in terms of the electrostatic interactions and chemical bonding between the metal surface and the corrosion inhibitor. Finally, compound 6 obtained the largest charge transference to the metal cluster.

Cyanoacetamide derivatives as corrosion inhibitors; Synthesis, Characterization, DFT and Monte Carlo simulation

Corrosion behavior of X65-type carbon steel exposed to 1M HCl aqueous solution was studied in the absence and presence of various concentrations of new synthesized 3-(4-chlorophenyl)-2-cyano-N-(4-hydroxyphenyl) acrylamide, abbreviated as (P2), and 6-amino-4-(4-chlorophenyl)-1-(4-hydroxyphenyl)-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile, abbreviated as (P3), at 25oC. Potentiodynamic polarization data indicated that the synthesized Cyanoacetamide derivatives suppress both anodic and cathodic reactions via adsorption on the carbon steel surface and blocking the active sites. The adsorption of the inhibitor molecules forms a protective film which decreases the surface heterogeneity. Electrochemical impedance spectroscopy (EIS) measurements reveal that as the inhibitor concentration is increased, both the inhibition efficiency (η%) and the charge transfer resistance (Rt) are increased while the electrochemical double layer capacity (Cdl) is decreased. The experimental impedance data were analyzed according to a proposed equivalent circuit model for the electrode/electrolyte interface. Chemical descriptors are calculated through the density functional theory (DFT), also adsorption of inhibitors on the metal surface investigated through Monte Carlo simulation. The mechanism of corrosion inhibition was discussed given the obtained results of surface analysis and the molecular structure of the additive obtained from quantum chemical calculations. Keywords: Corrosion inhibition; Polarization; Electrochemical impedance spectroscopy (EIS); Surface analysis; Quantum chemical calculations

Batch and Column Extraction of Lead from Al-Doura Oil Refinery Soil

The aim of this research is to investigate the extraction of lead (Pb) from soil of Al-Doura oil refinery in Baghdad/Iraq. Ethylenediaminetetraacetic acid disodium salt (Na2EDTA) and Hydrochloric acid (HCl) solution were used as extractants. Soil washing method was practiced in two ways, batch extraction and column extraction experiments. A set of batch experiments were carried out at different conditions of extractant (Na2EDTA, HCl) concentration, contact time, pH and agitation speed. From the batch experiments, the maximum removal percentages of Pb that have been obtained were 70 % using Na2EDTA (0.1M) at pH 4 , agitation speed 200 and at equilibrium time 4 hours and 65 % using HCl (1M) at pH 1.08 , agitation speed 200 at equilibrium time 5 hours. 
 Column experiments were conducted at different conditions of extractant (Na2EDTA, HCl) concentration, contact time and flow rate. The maximum removal percentages of Pb were 78% using Na2EDTA (0.1M) at pH 4 , flow rate 30 ml/hr and equilibrium time 8 hours and 75% using HCl (1M) at pH 1.08, flow rate 20 ml/hr and equilibrium time 10 hours. 
 The column extraction proved that the extractant volume required to achieve high removal efficiency is less than that of the batch extraction, but requires a longer contact time.
 The experimental data of batch and column extraction were applied in four kinetic models; first order, parabolic diffusion, two constant and Elovich model to find best fit model for extraction system. For batch extraction, the parabolic diffusion and two-constant models gave the best correlation {coefficient of determination (R2)} with experimental data using HCl and Na2EDTA respectively. While for column extraction, Elovich model gave good correlation with experimental data.

Total Synthesis of Stemarene and Betaerene Diterpenoids: Divergent Ring-Formation Strategy and Late-Stage C–H Functionalization

A unified protecting group-free approach to two stemarene and two betaerene diterpenoids through a bioinspired two-phase strategy has been developed, and three of them were obtained for the first t...

Removal of Pb(II) Ion from Aqueous Solution Using Dithizone-Immobilized Natural Bentonite

Removal of Pb(II) ion using activated and dithizone-immobilized natural bentonites has been carried out. Natural bentonite was activated by immersing and stirring the bentonite in 6M HCl solution. The dithizone-immobilized natural bentonite was prepared by mixing the bentonite and dithizone in toluene at 50 °C for 6 h and the immobilized adsorbents was characterized by FTIR and XRD. The dithizone immobilization is aimed to increase the capacity and selectivity of the adsorbent towards Pb(II) ions. Characterization results suggest that dithizone has been successfully immobilized on the surface of bentonites indicated by the emerge of new peaks of dithizone in the FTIR and XRD spectra. The optimum conditions for the adsorption of Pb(II) ion are at pH 5, 0.1 gram of adsorbent mass, initial concentration of 70 ppm and contact time of 60 minutes. Experimental results show that the adsorption of Pb(II) on both adsorbents follows pseudo second order kinetic models and best described by the Langmuir isotherm models with the adsorption capacities of 0.452 and 0.506 mg/g for activated and dithizone-immobilized natural bentonites, respectively. It also reveals that the adsorption energies of Pb(II) ion on activated and dithizone-immobilized natural bentonites are 27,17 and 29,59 kJ/mol, respectively, suggesting that the adsorption of Pb(II) ion on both adsorbent is chemisorption.

Synthesis, characterization and evaluation of the corrosion inhibition on mild steel of two new Schiff bases derived from 4,4'-diaminobiphenyl: Density functional theory investigation

The present work deals with the synthesis of two new heterocyclic Schiff bases, namely 4,4’-bis(3-thienylideneimino) biphenyl (HL1) and 4,4’-bis(2-furylideneimino) biphenyl (HL2), by condensing 4,4'-diaminobiphenyl with 3-carboxaldehyde thiophene and 2-carbaxaldehyde furan, respectively. The obtained compounds were characterized by different spectroscopic techniques. The corrosion inhibition properties of the investigated Schiff bases were evaluated for mild steel in 1M HCl medium, using weight loss measurement, potentiodynamic polarization and impedance spectroscopy. All the measurements showed that the inhibition efficiency increases with the increase in the inhibitor’s concentrations. Furthermore, the experimental results were confirmed by the quantum chemical calculations using the density functional theory (DFT). The different proprieties for each compound have been analyzed by means of the HOMO-LUMO to determine the energy gap (∆E), Electron affinity (EA), Ionization potential (I), Global Electrophilicity (ω), Global Hardness (η) and Chemical Potential (µ). The fraction of electrons transferred (ΔN) and the total energy (TE) were also calculated. The local selectivity and reactivity have been analyzed through the Fukui function in order to compare the possible sites for nucleophilic and electrophilic attacks. The polarization curves studies showed that both tested compounds are mixed-type inhibitors. The DFT investigation is in good accordance with the experimental results.

Atriplex leucoclada extract: A promising eco-friendly anticorrosive agent for copper in aqueous media

Conventional organic and inorganic corrosion inhibitors are noxious and hazardous to living organisms and the environment. Therefore, the use of plant extracts as potential corrosion inhibitors for metals has attracted considerable attention because these compounds are renewable and can have low toxicity, mainly when derived from edible plant species. Here, we prepared Atriplex leucoclada extract (ALE, 0–8g/L) and tested its effectiveness as an eco-friendly copper corrosion inhibitor in 1M HCl using several characterisation techniques, such as potentiodynamic polarisation experiments at the open-circuit potential, electrochemical impedance spectroscopy, and surface morphology. Adsorption isotherm modelling based on the Langmuir monolayer adsorption model revealed that the antioxidant flavonoids and polyphenolic compounds in ALE adsorb on the surface of copper and act as mixed-type inhibitors to reduce copper corrosion. Notably, the use of ALE resulted in a high (91.5%) inhibition efficiency at room temperature. Our results demonstrate the potential of ALE as a corrosion inhibitor for copper in acidic media and enrich knowledge regarding the use of plant extracts as green corrosion inhibitors.