ABSTRACT
In this study, a silver nanoparticle anchored transparent tape sensor was used to detect 1,4-bis(2-aminoethyl)piperazine functionalized GO (AEP-GO) adsorbed on carbon steel surface utilizing the surface-enhanced Raman scattering (SERS) technique. SERS detection enabled the extreme amplification of Raman signals emitted by inhibitor molecules in order to describe their adsorption behavior on metallic/alloy surfaces. The strong corrosion inhibition performance of AEP-GO against carbon steel corrosion in 15 % HCl solution was proven by weight loss, electrochemical measurements and surface characterization techniques in a previous study. The SERS analysis showed the Raman peaks intensity of AEP-GO on the carbon surface gradually increases with increasing AEP-GO concentration. The increasing intensity with concentration correlated well with the previously reported weight loss and electrochemical results. DFT calculation was also carried out to understand the nature of interaction between the adsorbed AEP-GO molecules and the silver nanoparticles. The AEP-GO_Ag adduct's optimized structure reveals the silver metals approached the oxygen atom at the GO epoxy group in AEP-GO rather than the oxygen atoms at the carbonyl and hydroxyl groups. With no restrictions on substrate materials, the fabricated SERS sensor created in this study can be employed as a versatile sensor to characterize corrosion adsorption processes on metal surfaces.
ABSTRACT
Experimental weight loss and electrochemical measurements were used at ambient and high temperatures to evaluate the corrosion inhibition efficacies of diaminodecane functionalized graphene oxide (DAD-GO) and diaminododecane functionalized graphene oxide (DADD-GO) against carbon steel corrosion in 15.0 %HCl, mimicking an acidizing environment in an oil/gas well. The GO was made from waste graphite and then grafted with the diaminoalkanes (DAD & DADD). The GO and functionalized GOs were described using FTIR, Raman, TEM, and TGA. Concentration and temperature effects on the inhibitors'performance were also looked into. The inhibition efficiency increased with concentration at room temperature, reaching a maximum of 84 % for DAD-GO and 78 % for DADD-GO at a concentration of 5 ppm for both. At the temperatures studied, the inhibitors performed well at extremely low concentrations; however, as the temperature rises, the inhibitor's performance decreases. According to the PDP measurement, the inhibitors function primarily as mixed-type inhibitors. The Langmuir adsorption theory was found to be followed by thestudied compound. AFM, SEM, EDX, and FTIR characterization of the steel surfaces revealed that the functionalized GOs molecules adsorbed on the steel to create a protective layer that insulated the steel from aggressiveacid assault after the immersion time (24 h) in the inhibited solutions. DFT calculations were utilized to determine the relative stability of functionalized GOs toGOand to learn more about the inhibitor molecules' interactions with the steel surface. The DFT calculations corroborated the experimental findings. This study is important in tackling two significant environmental concerns: corrosion and waste management because GO is manufactured from waste graphite.
Subject(s)
Graphite , Steel , Corrosion , Steel/chemistry , Carbon , Oil and Gas FieldsABSTRACT
In this study, Kola nut extract (KE) was evaluated for inhibiting ability towards low carbon steel corrosion in 1 M HCl solution using weight loss and electrochemical techniques. The surface of the corroded carbon steel was examined by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Elemental composition of the corrosion products and/or adsorbed inhibitor film on the carbon steel surface was determined with the aid of an energy-dispersive X-ray spectroscopy (EDX). The ultraviolet-visible (UV-vis) experiments were also performed to get information about the interaction of KE with the carbon steel surface. It was found that KE exhibited good corrosion protection property. From weight loss technique, corrosion rate was reduced from 0.387 to 0.054 mm/year by 700 ppm of KE at room temperature after 24 h immersion and this corresponded to inhibition efficiency (IE) of 86%. The IE however depreciated with rise in temperature. FTIR results reveal that KE interacted with the carbon steel surface through the O and N heteroatoms of its phytoconstituents. FTIR spectroscopy, UV-vis, SEM, AFM, and EDX data provided proof of KE adsorption on the steel surface as reason for the corrosion inhibition.
Subject(s)
Cola , Steel , Carbon , Corrosion , Plant ExtractsABSTRACT
A mutual prodrug (1) of ibuprofen and sulphanilamide has been synthesized with dual activity and improved toxicity profile. The synthesized compound has been characterized by elemental analysis, FT-IR, 1HNMR, 13CNMR and ESI-MS. The molecular geometry of the compound (1) was optimized using density functional theory (DFT/B3LYP) method with the 6-311G(d,p) basis sets in ground state. Geometric parameters (bond lengths, bond angles, torsion angles), vibrational assignments, chemical shifts and thermodynamics of the compound (1) has been calculated theoretically and compared with the experimental data. Comparative AutoDock study of compound (1) with cyclooxygenase enzymes (COX-1 and COX-2) were performed involving docking for possible selectivity of our prodrug within the two Cox enzymes. The highest binding affinities of -8.7â¯Kcal/mol and -8.1â¯Kcal/mol has been obtained for COX-1 and COX-2 enzymes respectively. Compound (1) exhibited enhanced anti-inflammatory, anti-ulcer and free radical scavenging activities as compared with the parent drugs. Based on various in vitro and in vivo tests it is suggested that the Compound (1) is more active than the parent drugs. Moreover, LD50 of compound (1) is higher than parent drug i.e. ibuprofen and sulphanilamide suggesting that the synthesized compound is much safer than its parent analogous.
