Synthesis, characterization, and evaluation of polymeric surfactants derived from PET plastic waste as green corrosion inhibitor of steel surfaces in marine environment for heavy industry.

The aim of this work was to prepare a nonionic polymeric surfactant from a recycled product of poly(ethylene terephthalate) plastic waste, PET. In this respect, PET waste was subjected to reverse polymerization (depolymerization) via reaction with both ethylene diamine (EDA) in the presence of a catalyst and propylene glycol (PG) in the presence of a transesterification catalyst. The corresponding products obtained were poly amino amide (PETAA) and poly glycol ester (PETPG), respectively. The obtained materials reacted with oleic acid to produce N1,N4-bis(2-((E)-octadec-9-enamido)ethyl)terephthalamide (PETAA-OL) and 2-(2-(((E)-octadec-8-enoyl)oxy)propoxy)ethyl (2-(2-(((E)-octadec-9-enoyl)oxy)propoxy)ethyl) terephthalate (PETPG-OL). The prepared materials were characterized by FT-IR, 1HNMR, and elemental analysis. It was evaluated as a corrosion inhibitor for carbon steel used in the petroleum industry in the marine environment. Chemical, analytical, and electrochemical techniques were used for the evaluation of the corrosion inhibition efficiency of the prepared polymeric surfactants. The effects of the polymeric surfactant concentration and reaction temperature were studied. The inhibition efficiency was found to increase with increasing concentration and decrease with rising temperature. The inhibition due to the adhesion and adsorption of the polymeric material on the steel surface agrees with the Langmuir adsorption isotherm model. The amount of dissolved iron in the corrosive medium due to the corrosion process was estimated using atomic absorption spectroscopy (AAS). It was found that the dissolution of iron was decreased by adding the prepared nonionic surfactants. Potentiodynamic polarization data indicate the mixed-type nature of surfactant inhibitors. According to the potentiodynamic polarization data, the prepared surfactant boosts polarization resistance and inhibition performance by adsorbing on the metal/electrolyte interface. The addition of inhibitor molecules to the aggressive medium produces a negative shift in the open-circuit potential due to the retardation of the cathodic reaction. The surface morphology of steel was examined using SEM. A protective coating of inhibitor molecules forms on the steel surface, according to the SEM measurements of the surface. The data obtained from different techniques are in good agreement, indicating good inhibition efficiency of the prepared nonionic surfactants derived from plastic waste in a marine environment.

Manufacturing of Corrosion Inhibitors and Flow Improvers from Recycling of Waste at Hail City, Saudi Arabia: Physicochemical and Electrochemical Studies on Steel in Petroleum Industries.

The aim of the present research paper is to convert daily waste materials generated by human activity at Hail city into useful petroleum additives. In this respect, novel multifunctional corrosion inhibitors working as inhibitors and flow improvers for crude oil were prepared. Polyethylene terephthalate (PET) plastic waste is used in the production of corrosion inhibitors and flow improvers for petroleum crude oil. A multifunctional corrosion inhibitor for the SABIC carbon steel in corrosive seawater for application in the petroleum industry was manufactured using PET waste that was gathered, cleaned, and used as starting materials. The PET green recycling method takes place via the Abdel-Hameed green recycling reported method. In the first step, PET waste was reacted without a solvent with a diamine to form the diamino derivative of phthalic acid amide (PETAA), which was characterized by FT-IR, 1HNMR, and elemental analysis. In the presence of a catalyst, the used recycling method is a solvent-free green recycling process that is environmentally friendly. Chemical and electrochemical measurements were performed, and the effects of concentration and temperature were studied. The inhibition efficiency was found to increase with concentration. A maximum inhibition of 97% was obtained using 4000 ppm from the prepared PETAA inhibitor, while the efficiency decreased with temperature. Potentiodynamic polarization (PDP) data indicates the mixed-type nature of the used inhibitor. According to potentiodynamic polarization data, the inhibitor boosts polarization resistance and inhibition performance by adsorbing on the metal/electrolyte interface. The data from electrochemical impedance spectroscopy (EIS) show that the charge-transfer mechanism is the primary governing factor in the steel dissolution process. The size of the semicircle grows in direct proportion to the concentration of the inhibitor. The prepared additive acts as a flow improver (viscosity improvers and pour point depressants) for waxy crude oil, indicating that it can be used in the manufacturing of multifunctional inhibitors in the petroleum industry. The depression in the pour point temperatures depended on the concentration and composition of the additive prepared from the plastic waste collected from Hail city.

Green Synthesis of a Novel Cationic Surfactant Based on an Azo Schiff Compound for Use as a Carbon Steel Anticorrosion Agent.

The new cationic surfactant-based azo Schiff compound (azoS8) was prepared, characterized, and investigated as a corrosion inhibitor for carbon steel in 1 M HCl by means of electrochemical approaches in this study. The chemical structure of azoS8 has been verified by the FTIR and 1H NMR spectra. According to the electrochemical system, the examined surfactant is a mixed-type inhibitor. The surfactant azoS8 was an adequate corrosion inhibitor, as evidenced by the reduction in corrosion current densities and the rise in coverage of the surface identified with an evolving inhibitor amount. When the surfactant azoS8 had been added, the capacitive cycle loops on the Nyquist plots were broader, and the dimension of these loops expanded with surfactant azoS8 concentration. This implies that the amount of surfactant azoS8 led to an improvement in the impedance of the steel electrode. The surfactant azoS8 adsorption system is well suited to the Langmuir adsorption isotherm. It was discovered that azoS8 had a Gibbs free energy change value of -27.72 kJ mol-1, which is a mixed adsorption mechanism containing both physisorption and chemisorption.

The Protective Effects of Melatonin on Aluminum-Induced Hepatotoxicity and Nephrotoxicity in Rats.

Aluminum (Al) is a ubiquitous element with known toxicity for both humans and animals. Herein, we aimed to investigate the potential role of melatonin (MEL) in hepatotoxicity and nephrotoxicity following aluminum chloride (AlCl3) treatment in rats. Adult male rats were treated with AlCl3 (34 mg/kg bwt) for eight weeks. Exposure to AlCl3 enhanced the serum activities of the liver transaminases (alanine aminotransferase and aspartate aminotransferase) and increased the level of bilirubin, in addition to the serum kidney function markers urea and creatinine. AlCl3 intoxication boosted oxidative stress, as evidenced by increases in the levels of lipid peroxidation (LPO) and nitric oxide (NO) along with simultaneous decreases in the levels of glutathione (GSH), various antioxidant enzymes, and Nrf2 mRNA expression. MEL (5 mg/kg bwt) treatment repressed LPO and NO levels, whereas it augmented GSH content. The activities of the antioxidant enzymes GPx, SOD, CAT, and GR were also restored concomitantly when MEL was administered before AlCl3. MEL also suppressed the apoptotic effect of AlCl3 by enhancing Bcl-2 protein expression in the liver and kidney and decreasing the expression levels of proinflammatory cytokines. Histopathological findings in the liver and kidney tissues confirmed the beneficial effect of MEL against AlCl3 toxicity. These findings indicate that MEL prevents AlCl3 toxicity by enhancing the antioxidant defense system.