Naser M. Alandis

Effect of thiosemicarbazones on corrosion of steel in phosphoric acid produced by wet process

Abstract Corrosion inhibition of steel in phosphoric acid (H3PO4) by thiosemicarbazide derivatives was studied using different chemical and electrochemical techniques. Protection efficiency up to 99% was obtained with small amounts (10−4 M) of cinnamaldehyde thiosemicarbazone (CTSCN). The order of increasing inhibition efficiency was correlated with the modification of the molecular structure of the inhibitors. Empirical kinetic relationship was obtained describing the experimental data obtained from the different compounds used in this investigation. Potentiodynamic polarization curves indicated that the compounds acted primarily as mixed-type inhibitors. Electrochemical impedance spectroscopy showed that the charge-transfer resistance increased and the capacitance of the double layer decreased with increasing the concentration of the inhibitor in the medium, confirming adsorption process mechanism. At high concentrations (> 104 M), the capacitance of the double layer leveled off since maximum double-lay...

Herbs as New Type of Green Inhibitors For Acidic Corrosion of Steel

Corrosion inhibition of steel in sulphuric acid by six different herb plants has been studied using a.c and d.c electrochemical techniques. The environmentally friendly investigated compounds are namely: thyme, coriander, hibiscus, anis, black cumin and Garden cress. Electrochemical impedance spectroscopy has been successfully used to evaluate the performance of these compounds. The ac measurements showed that the dissolution process is activation controlled. Bode and theta diagrams show only one time constant (τ). Potentiodynamic polarization curves indicate that the studied compounds are mixed-type inhibitors. The order of increasing inhibition efficiency was correlated with the change of the constituent active materials of the compounds. Thyme, which contains the powerful antiseptic thymol as the active ingredient, offers excellent protection for steel surface. Unteruberschrift (Ubersetzung) Corrosion inhibition of steel in sulphuric acid by six different herb plants has been studied using a.c and d.c electrochemical techniques. The environmentally friendly investigated compounds are namely: thyme, coriander, hibiscus, anis, black cumin and Garden cress. Electrochemical impedance spectroscopy has been successfully used to evaluate the performance of these compounds. The ac measurements showed that the dissolution process is activation controlled. Bode and theta diagrams show only one time constant (τ). Potentiodynamic polarization curves indicate that the studied compounds are mixed-type inhibitors. The order of increasing inhibition efficiency was correlated with the change of the constituent active materials of the compounds. Thyme, which contains the powerful antiseptic thymol as the active ingredient, offers excellent protection for steel surface.

Thermodynamic and Kinetic Studies for the Adsorption of Fe(III) and Ni(II) Ions From Aqueous Solution Using Natural Bentonite

In this study, the adsorption behavior of natural bentonite with respect to Fe(III) and Ni(II) has been studied in order to consider its application to purity metal finishing wastewaters. During the adsorption process, batch technique is used, and the effects of pH, bentoite amount, temperature, heavy metal concentration, bentonite treatment (calcinations of natural bentonite at 700°C, washing by deionized water to remove the excess salt from bentonite surface), and agitation time on adsorption efficiency are studied. The washed and calcined bentonite samples were labeled by WB and CB, respectively. The pH-dependence of Fe(III) and Ni(II) sorption on the bentonite is significantly more noticeable, indicating a major contribution of surface complexation at the edge sites. It was determined that adsorption of Fe(III) and Ni(II) is well fitted by the second order reaction kinetic. Furthermore, the sorption rate of Fe(III) was higher than the sorption rate of Ni(II). Adsorption of Fe(III) and Ni(II) on NB appeared to follow Langmuir isotherm. In addition, calculated and experimental adsorbed amounts of Fe(III) by the unit NB mass are very higher than Ni(II). The paper also discusses the thermodynamic parameters of the adsorption (the Gibbs free energy, entropy, and enthalpy). Our results demonstrate that the adsorption process was spontaneous and endothermic under natural conditions. Also the adsorption capacity of bentonite for Fe(III) Ni(II) and increases with increased bentonite dose. According to the equilibrium studies, the selectivity sequence can be given as Fe(III) > Ni(II). The adsorbed amount of Fe(III) and Ni(II) on washed bentonite (WB) were very higher compared to NB and CB. Our results show that bentonite could especially WB be considered as a potential adsorbent for Fe(III) and Ni(II) removal from aqueous solutions.

Optical and electrical studies of polyaniline/ZnO nanocomposite

Polyaniline (Pani)/ZnO nanocomposite with diameter 40-50nm was successfully fabricated by coprecipitation method of ZnO via in situ polymerization of Pani. X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), fourier transformation infrared (FT-IR), UV-Vis absorption spectra, thermogravimetric analysis (TGA), and electrical properties were studied. HRTEM studies showed that the prepared ZnO nanoparticles were uniformly dispersed and highly stabilized throughout the polymer chain and formed uniform metal oxide-conducting polymer nanocomposite material. UV-Vis spectra of Pani/ZnO nanocomposite were studied to investigate the optical behavior after doping the ZnO nanoparticle into the polymer matrix. The inclusion of ZnO nanoparticle gives rise to the red shift of π-π* transition of Pani. The nanocomposite was found to be thermally stable upto 130°C and showed conductivity value of 3.0 × 10-2 Scm-1.

Synthesis and the Antiperoxidase Activity of Seleno Analogues of the Antithyroid Drug Propylthiouracil

The synthesis of 6-n-propyl-2-selenouracil (PSeU, Ib) and its methyl derivative (MSeU, Ic) are described. Replacement of the sulfur atom at C2 by selenium increased with antiperoxidase activity of these analogues five fold when compared to the clinically used antithyroid drug propylthiouracil (PTU). The structure-activity relationships of these agents are discussed.

Development of castor oil based poly(urethane-esteramide)/TiO 2 nanocomposites as anticorrosive and antimicrobial coatings

Castor oil based polyesteramide (CPEA) resin has been successfully synthesized by the condensation polymerization of N-N-bis (2-hydroxyethyl) castor oil fatty amide (HECA) with terephthalic acid and further modified with different percentages of 7, 9, 11, and 13 wt.% of toluene-2,4-diisocyanate (TDI) to obtain poly(urethane-esteramide) (UCPEA), via addition polymerization. TiO2 (0.1, 0.2, 0.3, 0.4, and 0.5 wt%) nanoparticles were dispersed in UCPEA resin. The structural elucidation of HECA, CPEA, and UCPEA has been carried out using FT-IR, 1H-NMR, and 13C-NMR spectroscopic techniques while physicochemical and physicomechanical properties were investigated by standard methods. Thermal stability and molecular weight of UCPEA have been assessed by thermogravimetric analysis (TGA) and gel permeation chromatography (GPC), respectively. Furthermore, the corrosion behavior of UCPEA coatings on mild steel has been investigated by potentiodynamic polarization measurements in different corrosive environments (3.5 wt% HCl, 5 wt% NaCl, 3.5 wt% NaOH, and tap water) at room temperature and surface analysis by scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The antibacterial activities of the UCPEA were tested against bacteria and fungi by agar disc diffusion method. The results of this study have revealed that UCPEA nanocomposite coatings exhibit good physicomechanical, anticorrosion and antimicrobial properties, which can be safely used up to 200°C.

Microwave-assisted preparation of urethane-modified polyetheramide coatings from Jatropha seed oil

We have developed urethane-modified polyetheramide (UPEtA) by the condensation polymerization reaction of N,N-bis (2-hydroxy ethyl) Jatropha oil fatty amide and hydroquinone to form polyetheramide (PEtA). Jatropha PEtA was further treated with toluylene-2,6-diisocyanate (TDI) in different weight percentage (15, 20, 25 wt%) to produce UPEtA. The structural elucidation of PEtA and UPEtA was carried out by Fourier transform infrared, proton nuclear magnetic resonance and carbon-13 nuclear magnetic resonance spectroscopic techniques. The coatings of UPEtA were prepared on mild steel strips to investigate their physico-mechanical and corrosion resistance performance. Physico-chemical and physico-mechanical tests were performed by standard methods. Corrosion resistance tests were examined in different corrosive media, such as 3.5 wt% HCl, 3.5 wt% NaOH, 5.0 wt% NaCl, water and xylene. The thermal behavior of UPEtA was studied by thermogravimetric analyses. Our studies revealed that UPEtA may find application as an eco-friendly corrosion protective coating and may be safely used up to 200oC.

Oxidative dehydrogenation of ethane over movmnw oxide catalysts

Catalysts based on mixed oxide of MoVMn are active at relatively low temperature for oxidative dehydrogenation of ethane. Incorporation of tungsten into MoVMn oxides enhances the catalytic activity. Enhancement of the activity is explained in the light of acid-base interaction accompanied with a redox mechanism of surface reoxidation.

Development of Poly(urethane esteramide) Coatings from Pongamia glabra Oil as Anticorrosive Applications

In this study, ethylene glycol polyesteramide (Eg-PEA) was synthesized from N,N-bis (2-hydroxy ethyl) pongamia oil fatty amide and ethylene glycol tetraacetic acid (EGTA) through condensation polymerization. It was further modified by toluene 2,4-diisocynate in different wt.% (20, 25, 30, and 35) to obtain urethane-modified polyesteramide (Eg-UPEA). The synthesized resins were characterized using FT-IR, 1H NMR, and 13C NMR spectroscopic techniques, and molecular weight was determined by gel permeation chromatography (GPC). Physico-chemical and physico-mechanical analyses were carried out by standard laboratory methods. Thermal studies of Eg-UPEA were undertaken by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques. To evaluate corrosion prevention performance Eg-UPEA-coated mild steel strips were investigated by potentiodynamic polarization in different corrosive media (5 wt.% NaCl, 3 wt.% HCL, 2.5 wt.% NaOH, and tap water) at room temperature. Thermal analysis revealed that Eg-UPEA30 may find application as an environmentally friendly corrosion protective coating and may be safely used up to 250°C.

Vegetable-Oil-Based Hyperbranched Polyester-Styrene Copolymer Containing Silver Nanoparticle as Antimicrobial and Corrosion-Resistant Coating Materials

Pongamia oil (PO) was converted to Pongamia oil hydroxyl (POH) via epoxidation process. The esterification of POH with linolenic acid was carried out to form hyperbranched polyester (HBPE), and further styrenation was performed at the conjugated double bond in the chain of linolenic acid. After styrenation, silver nanoparticle was added in different weight percentages (0.1–0.4 wt%). The structural elucidation of POH, HBPE, and HBPE-St was carried out by FT-IR, 1H-NMR, and 13C-NMR spectroscopic techniques. Physicochemical and physicomechanical analyses were performed by standard method. Thermal behavior of the HBPE-St was analyzed by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The coatings of HBPE-St were prepared on mild steel strips. The anticorrosive behavior of HBPE-St resin-based coatings in acid, saline, and tap water was evaluated, and the molecular weight of HBPE-St was determined by gel permeation chromatography (GPC). The antibacterial activities of the HBPE-St copolymers were tested in vitro against bacteria and fungi by disc diffusion method. The HBPE-St copolymers exhibited good antibacterial activities and can be used as antimicrobial and corrosion-resistant coating materials.