scholarly journals Characterization and utilization of Sargassum linifolium and Stypopodium schimperi polysaccharides as blue inhibitors for steel electo-polishing

2020 ◽  
Author(s):  
Abeer A. M. El-Sayed ◽  
F. M. Abouzeid ◽  
Mona M. Ismail ◽  
Gehan M. ElZokm
Keyword(s):  
Steel Surface ◽  
Inhibition Efficiency ◽  
Adsorption Process ◽  
Activation Parameters ◽  
Limiting Current ◽  
High Concentration ◽  
Surface Appearance ◽  
Solution Interface ◽  
Ft Ir ◽  
Crude Polysaccharide

Abstract Different polysaccharides extracts (crude polysaccharide, fucoidan and alginate) from Sargassum linifolium and Stypopodium schimperi were examined as inhibitors for carbon-steel anodic dissolution process in 8M phosphoric acid. Anode potential –limiting current relationship was measured and comparing of gradually increasing algae extract concentrations (from 20 to 350 ppm). The limiting current decrease while inhibition Efficiency % increases as the concentrations of all these extracts increase. Fucoidan from S. linifolium is considered as most retardation effect. The extracts retardation mechanism is depending on adsorption process at the steel metal which proved by SEM. Also, SEM shows that high concentration (350 ppm) from St. schimperi crude polysaccharide, Sargassum linifolium fucoidan and Stypopodium. schimperi alginate extracts have promising effect on the surface texture. The data of Langmuir and the kinetic-thermodynamic isotherms were determined to clarify the nature of adsorption of extract on metal –solution interface. The activation energy (Ea) and activation parameters (ΔH*, ΔS*, and ΔG*) were determined and gave indication for strong interaction between the inhibitor and the steel surface. The extract feature was investigated via FT-IR. The polysaccharides from brown algae especially fucoidan manifest preferable as natural electro-polishing blue inhibitor. Surface morphology study confirmed that addition of algae extract to steel dissolution bath enhance surface appearance and its texture quality to great extent.

scholarly journals Inhibition of Pipeline Steel Corrosion in 0.5 M H2SO4 Using Cotyledon of Chrysophyllum Albidum

2020 ◽  
Vol 24 (4) ◽  
pp. 691-697
Author(s):  
E.P. Othaki ◽  
N.C. Ngobiri
Keyword(s):  
Corrosion Inhibitors ◽  
Inhibition Efficiency ◽  
Adsorption Process ◽  
Pipeline Steel ◽  
Steel Corrosion ◽  
Langmuir Adsorption ◽  
Extract Concentration ◽  
Ir Studies ◽  
Ft Ir ◽  
As Adsorption

The corrosion inhibition characteristics of Chrysophyllum albidum cotyledon extract was studied as a green and sustainable corrosion inhibitors for pipeline steel in acidic environment attemperatures, 303,313 and 323K using gravimetric technique.The results obtained showed that the inhibition efficiency increased with increase in extract concentration but decrease with increase in temperature. The extract attained an inhibition efficiency of 94 % with 5 g/L at 303 K and 52.2 % with 1 g/L at 333K. Also increase in concentration of the extract lead to increase in activation energydepicting an exothermic process.Fourier transform infrared spectroscopy (FT-IR) studies showed the mode of inhibition as adsorption of phytochemicals from the extract on pipeline steel surface. Langmuir adsorption isotherm best fitted into the adsorption process which is spontaneous and physical. Keywords: Chrysophyllum albidum, Pipeline steel, Inhibition, Adsorption.

POLYVINYLPYROLLIDONE AND POLYACRYLAMIDE AS CORROSION INHIBITORS FOR MILD STEEL IN ACIDIC MEDIUM

2008 ◽  
Vol 15 (03) ◽  
pp. 277-286 ◽  
Author(s):  
S. A. UMOREN ◽  
I. B. OBOT
Keyword(s):  
Adsorption Isotherm ◽  
Corrosion Rate ◽  
Mild Steel ◽  
Acidic Medium ◽  
Corrosion Inhibitors ◽  
Inhibition Efficiency ◽  
Adsorption Process ◽  
Physical Adsorption ◽  
Activation Parameters ◽  
Temkin Adsorption Isotherm

The corrosion inhibition of mild steel in 1 M H 2 SO 4 in the presence of polyvinylpyrollidone (PVP) and polyacrylamide (PA) as inhibitors at 30–60°C was studied using gravimetric and gasometric techniques. The inhibition efficiency (1%) increased with increase in concentration of the inhibitors. Increase in temperature increased the corrosion rate in the absence and presence of inhibitors but decreased the inhibition efficiency. Both PVP and PA were found to obey Temkin adsorption isotherm and Kinetic-Thermodynamic Model of El-Awady at all the concentrations and temperatures studied. Phenomenon of physical adsorption is proposed from the activation parameters obtained. Thermodynamic parameters reveal that the adsorption process is spontaneous. PVP was found to be a better inhibitor than PA.

INHIBITIVE EFFECT OF L–OH ON THE CORROSION OF AUSTENITIC CHROMIUM–NICKEL STEEL IN H2SO4 SOLUTION

2008 ◽  
Vol 15 (04) ◽  
pp. 435-442 ◽  
Author(s):  
S. M. A. HOSSEINI ◽  
M. AMIRI ◽  
A. MOMENI
Keyword(s):  
Acid Solution ◽  
Steel Surface ◽  
Inhibition Efficiency ◽  
Adsorption Process ◽  
Nickel Steel ◽  
H2so4 Solution ◽  
Free Energy Of Adsorption ◽  
Maximum Inhibition ◽  
Potentiostatic Polarization ◽  
Scanning Electron

The corrosion behavior of the austenitic chromium–nickel steel in different concentrations (0.001, 0.002, 0.005, and 0.01 M) of dimethyl 2-(2–hydroxy phenyl amino)-3-(triphenyl phosphoranilidin) butane dioate ( L – OH ) in 0.5 M H 2 SO 4 was investigated by potentiostatic polarization measurements. The effect of concentration and temperature on inhibition properties was determined. It was found that the presence of L – OH reduces markedly the corrosion rate of steel in the acid solution. The inhibition efficiency increases as the L – OH concentration is increased. Maximum inhibition efficiency (95%) was obtained for alloy in acid solution containing 0.01 M of L – OH . Thermodynamic parameters for adsorption of L – OH are calculated. It was found that the inhibitor is adsorbed on the steel surface and the experimental results are in agreement with Timken's isotherm. Negative values of the free energy of adsorption were obtained indicating the spontaneity of adsorption process. Scanning electron microscopy was done from the surface of exposed sample indicating uniform film on the surface of the alloy.

scholarly journals Lepidagathis alopecuroides methanol extract as corrosion inhibitor for mild steel in HCl

2021 ◽  
Vol 32 (1) ◽  
pp. 22-27
Author(s):  
Gloria I. Ndukwe ◽  
Habibat F. Chahul ◽  
Godwin Oodo
Keyword(s):  
Weight Loss ◽  
Mild Steel ◽  
Corrosion Inhibitor ◽  
Plant Extract ◽  
Linear Polarization ◽  
Steel Surface ◽  
Inhibition Efficiency ◽  
Methanol Extract ◽  
Activation Parameters ◽  
Aerial Parts

Abstract We report on the preliminary phytochemical screening of the methanolic extract of the aerial parts of Lepidagathis alopecuroides and its evaluation as a potential corrosion inhibitor for mild steel in aerated 1.0 M HCl by weight loss and linear polarization measurements. Weight loss measurements were conducted at 303, 313, 323 and 333 K. The results showed that L. alopecuroides inhibited the corrosion of mild steel in the acid solution with inhibition efficiency increasing with increase in the concentrations of the plant extract but decreased with increase in temperature. Linear polarization plots showed the plant extract to inhibit both the dissolution of the steel at the anode and the hydrogen evolution reaction (HER) at the cathode making it a mixed inhibitor. Temkin adsorption isotherms best modeled the adsorption of L. alopecuroides extract on the steel surface. From the values of the evaluated kinetic activation parameters in the study, the mechanism of physisorption is proposed for the adsorption of the plant extract on the steel surface.

scholarly journals Sintesis dan Karakterisasi Kitosan-Silika dari Abu Ampas Tebu sebagai Adsorben Logam Berat Cu(II)

2021 ◽  
Vol 6 (1) ◽  
pp. 70-77
Author(s):  
Tiane Pawitra ◽  
Adhi Setiawan ◽  
Tarikh Azis Ramadani
Keyword(s):  
Adsorption Process ◽  
Silica Content ◽  
Raw Material ◽  
High Concentration ◽  
Adsorption Method ◽  
Adsorption Ability ◽  
Bet Analysis ◽  
Large Particles ◽  
Ft Ir ◽  
Ir Analysis

Tingginya beban pencemaran logam berat Cu(II) di badan air dapat diatasi dengan proses adsorpsi menggunakan adsorben. Abu ampas tebu dapat menjadi alternatif bahan baku pembuatan adsorben karena memiliki kandungan silika yang melimpah. Kelemahan dari silika adalah memiliki sifat keasaman yang rendah serta memiliki oksigen sebagai atom donor yang bersifat lemah. Hal ini menyebabkan kemampuan adsorpsi silika menjadi kurang baik. Dalam rangka memperbaiki sifat tersebut maka, dilakukan modifikasi dengan menggunakan kitosan. Pada penelitian ini bertujuan untuk mensintesis serta mengkarakterisasi adsorben dari silika yang dimodifikasi dengan kitosan. Penelitian dilakukan untuk menganalisis dosis penambahan kitosan optimum dalam penurunan kandungan Cu(II) pada proses adsorpsi. Metode adsorpsi yang digunakan pada penelitian ini adalah sistem batch, yaitu dengan memasukkan setiap adsorben pada larutan Cu(II) 50 ppm selama 50 menit. Dosis penambahan kitosan yang ditambahkan sebanyak 0,5 gram; 1 gram; 1,5 gram; dan 2 gram. Hasil XRD menunjukkan adsorben yang disintesis bersifat amorf. Analisis FT-IR menunjukkan munculnya gugus fungsi –OH, Si-O-Si, Si-OH, Si-O-C, -NH, dan NH2. Uji BET menunjukkan bahwa adsorben memiliki luas area spesifik sebesar 2,33 m2/g. Morfologi dari silika berubah ketika dimodifikasi dengan kitosan dari yang sebelumnya adalah heterogen menjadi partikel-partikel besar yang teraglomerasi. Pada analisis EDX dapat diidentifikasi adanya unsur C, N, O, dan Si. Hasil penelitian menyatakan bahwa penambahan massa kitosan yang optimum adalah 2 gram dengan efisiensi removal logam berat Cu(II) sebesar 99,85%.ABSTRACTThe high concentration of Cu(II) in the water cause several diseases to the human being. It can be dealt with by the adsorption process using adsorbents. Bagasse ash can be an alternative raw material for making adsorbent due to its abundant silica content. The weakness of silica has low acidity and oxygen as a weak atomic donor. It causes a bad adsorption ability on the adsorbent. In order to improve those characteristics, modifications are needed, for example, by using chitosan. This research aims to synthesize and characterize the adsorbent from silica-chitosan. The research was conducted to analyze the optimum dosage of chitosan and reduce Cu(II) content in the adsorption process. The adsorption method used is a batch system by entering each adsorbent in a 50 ppm of Cu(II) solution for 50 minutes. The dosage of chitosan addition are 0,5 gram; 1 gram; 1,5 gram;and 2 gram. XRD results show that the synthesized adsorbent is amorphous. The presence of -OH, Si-O-Si, Si-OH, Si-O-C, -NH, and –NH2 groups are shown in FT-IR analysis. BET analysis shows that the adsorbent has an area of 2,33 m2/g. The morphology of silica changes when modified with chitosan from a heterogeneous form into agglomerated large particles. EDX analysis can identify the elements of C, N, O, and Si. The results of the research stated that the addition of the chitosan mass optimum is 2 grams with the ability to remove heavy metals Cu(II) of 99,85%

Adsorption Characteristics of Four Acid Dyes on Reaming Functionalized Mesoporous Material

2012 ◽  
Vol 550-553 ◽  
pp. 2301-2307
Author(s):  
Ping Ge ◽  
Feng Ting Li ◽  
Hong Yang
Keyword(s):  
Mesoporous Material ◽  
Adsorption Process ◽  
Activation Parameters ◽  
Sorption Kinetics ◽  
Acid Dyes ◽  
Solution Interface ◽  
Thermodynamic Activation Parameters ◽  
Pseudo Second Order ◽  
Enthalpy Of Sorption ◽  
Short Time

The present paper is aimed to investigate and develop renewable adsorption methods for four dyes removal from wastewater using pore-expanding mesoporous material. The sorption kinetics, sorption thermodynamic and the renewable adsorption test were evaluated. The adsorption process attained equilibrium within 60min, which show that the adsorbent can remove of the dye in a short time. It was shown that the process best described by the pseudo-second-order equation. Various thermodynamic activation parameters such as enthalpy of sorption △H, Gibbs energy change △G and entropy △S were estimated. The negative values of △G indicate that adsorption of dye with the adsorbent was spontaneous, while positive △H values indicative of endothermic nature of the adsorption. The negative △S values for the adsorbents show decreased randomness at the solid solution interface during the adsorption of dye. The adsorbent, washed by NaOH, can be reused by regeneration decolorizing process.

scholarly journals Evaluation of Plants and Weeds Extract on the Corrosion Inhibition of Mild Steel in Sulphuric Acid

2011 ◽  
Vol 8 (s1) ◽  
pp. S488-S494 ◽  
Author(s):  
Abida Begum
Keyword(s):  
Free Energy ◽  
Mild Steel ◽  
Sulphuric Acid ◽  
Steel Surface ◽  
Inhibition Efficiency ◽  
Adsorption Process ◽  
First Order ◽  
First Order Kinetics ◽  
Maximum Value ◽  
Kinetic Treatment

Experiments were performed in order to determine the inhibitive effects of extracts of plants and weeds namelyParthenium hysterophorus, Dathura stromonium, Azadirachta indica, Helianthus annuusleaves extract for mild steel in sulphuric acid by using weight loss and thermometric technique. Results demonstrated that, all the experimental inhibitors show an adsorption on steel surface according to Langmuir’s isotherm. The inhibition efficiency increased with increase in the concentration of all tested inhibitors to attain a maximum value at 1.0%. Free energy values for adsorption process show that the process is spontaneous. The kinetic treatment of the results shows first order kinetics.

scholarly journals Adsorptive, inhibitive and thermodynamics studies on the corrosion of mild steel in the presence of Mangifera indica gums

2019 ◽  
Vol 30 (2) ◽  
pp. 75-80
Author(s):  
Habibat F. Chahul ◽  
Elijah Maji ◽  
Tanko B. Danat
Keyword(s):  
Mild Steel ◽  
Linear Polarization ◽  
Adsorption Mechanism ◽  
Inhibition Efficiency ◽  
Adsorption Process ◽  
Mangifera Indica ◽  
Activation Parameters ◽  
Isotherm Models ◽  
Polarization Measurements ◽  
Mixed Type Inhibitor

Abstract The adsorption and inhibitive behavior of gums obtained from Mangifera indica tree was investigated at 303-333 K using weight loss and linear polarization measurements. The results obtained from both measurements showed that Mangifera indica gums inhibited the corrosion of mild steel in 1.0 M HCl. Linear polarization measurements revealed Mangifera indica gums to inhibit both the anodic and cathodic reactions on the surface of the mild steel thereby functioning as a mixed-type inhibitor. Adsorption behavior of the gums were approximated by the isotherm models of Langmuir, Freundlich and Temkin. The adsorption mechanism derived from the trend in inhibition efficiency as a function of temperature as well as kinetic and activation parameters signified Mangifera indica gums adsorbed on the surface of the mild steel through the mechanism of physisorption and that the adsorption process was exothermic and spontaneous.

scholarly journals Extraction of sugarcane bagasse arabinoxylan, integrated with enzymatic production of xylo-oligosaccharides and separation of cellulose

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Leila Khaleghipour ◽  
Javier A. Linares-Pastén ◽  
Hamid Rashedi ◽  
Seyed Omid Ranaei Siadat ◽  
Andrius Jasilionis ◽  
...  
Keyword(s):  
Sugarcane Bagasse ◽  
Sugar Content ◽  
Value Added ◽  
Apparent Molecular Weight ◽  
Bacillus Halodurans ◽  
Glycoside Hydrolase Family ◽  
High Concentration ◽  
Enzymatic Production ◽  
Successful Separation ◽  
Ft Ir

AbstractSugarcane processing roughly generates 54 million tonnes sugarcane bagasse (SCB)/year, making SCB an important material for upgrading to value-added molecules. In this study, an integrated scheme was developed for separating xylan, lignin and cellulose, followed by production of xylo-oligosaccharides (XOS) from SCB. Xylan extraction conditions were screened in: (1) single extractions in NaOH (0.25, 0.5, or 1 M), 121 °C (1 bar), 30 and 60 min; (2) 3 × repeated extraction cycles in NaOH (1 or 2 M), 121 °C (1 bar), 30 and 60 min or (3) pressurized liquid extractions (PLE), 100 bar, at low alkalinity (0–0.1 M NaOH) in the time and temperature range 10–30 min and 50–150 °C. Higher concentration of alkali (2 M NaOH) increased the xylan yield and resulted in higher apparent molecular weight of the xylan polymer (212 kDa using 1 and 2 M NaOH, vs 47 kDa using 0.5 M NaOH), but decreased the substituent sugar content. Repeated extraction at 2 M NaOH, 121 °C, 60 min solubilized both xylan (85.6% of the SCB xylan), and lignin (84.1% of the lignin), and left cellulose of high purity (95.8%) in the residuals. Solubilized xylan was separated from lignin by precipitation, and a polymer with β-1,4-linked xylose backbone substituted by arabinose and glucuronic acids was confirmed by FT-IR and monosaccharide analysis. XOS yield in subsequent hydrolysis by endo-xylanases (from glycoside hydrolase family 10 or 11) was dependent on extraction conditions, and was highest using xylan extracted by 0.5 M NaOH, (42.3%, using Xyn10A from Bacillus halodurans), with xylobiose and xylotriose as main products. The present study shows successful separation of SCB xylan, lignin, and cellulose. High concentration of alkali, resulted in xylan with lower degree of substitution (especially reduced arabinosylation), while high pressure (using PLE), released more lignin than xylan. Enzymatic hydrolysis was more efficient using xylan extracted at lower alkaline strength and less efficient using xylan obtained by PLE and 2 M NaOH, which may be a consequence of polymer aggregation, via remaining lignin interactions.

scholarly journals Experimental Theoretical Studies on Extract of Date Palm Seed as a Green Anti-Corrosion Agent in Hydrochloric Acid Solution

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3535
Author(s):  
Naba Jasim Mohammed ◽  
Norinsan Kamil Othman ◽  
Mohamad Fariz Mohamad Taib ◽  
Mohd Hazrie Samat ◽  
Solhan Yahya
Keyword(s):  
Carbon Steel ◽  
Hydrochloric Acid ◽  
Active Sites ◽  
Immersion Time ◽  
Steel Surface ◽  
Date Palm ◽  
Inhibition Efficiency ◽  
Experimental Results ◽  
Plant Materials ◽  
Carbon Steel Surface

Extracts from plant materials have great potential as alternatives to inorganic corrosion inhibitors, which typically have harmful consequences. Experimental and theoretical methodologies studied the effectiveness of agricultural waste, namely, date palm seed extract as a green anti-corrosive agent in 0.5 M hydrochloric acid. Experimental results showed that immersion time and temperature are closely related to the effectivity of date palm seed as a corrosion inhibitor. The inhibition efficiency reduced from 95% to 91% at 1400 ppm when the immersion time was increased from 72 h to 168 h. The experimental results also indicated that the inhibition efficiency decreased as the temperature increased. The presence of a protective layer of organic matter was corroborated by scanning electron microscopy. The adsorption studies indicated that date palm seed obeyed Langmuir adsorption isotherm on the carbon steel surface, and Gibbs free energy values were in the range of −33.45 to −38.41 kJ·mol−1. These results suggested that the date palm seed molecules interacted with the carbon steel surface through mixture adsorption. Theoretical calculations using density functional theory showed that the capability to donate and accept electrons between the alloy surface and the date palm seed inhibitor molecules is critical for adsorption effectiveness. The HOMO and LUMO result indicated that the carboxyl (COOH) group and C=C bond were the most active sites for the electron donation-acceptance type of interaction and most auxiliary to the adsorption process over the Fe surface.

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