Aloe vera mucilage as an eco-friendly corrosion inhibitor for bronze in chloride media: Combining experimental and theoretical researches

Aloe vera (L.) Burm.F. (=Aloe barbadensis Mill.), a widely recognized medicinal plant, holds a prominent position due to its potent cosmetic and medicinal attributes. The objective of this work is to develop a new eco-friendly corrosion inhibitor for bronze B66 that is non-toxic, simple to apply, cost-effective, stable, and reversible. To achieve this goal, we initially devised an improved and cost-efficient method for extracting Aloe vera mucilage (AVM). Then we tested as corrosion inhibitor for bronze B66 in 3 % NaCl using gravimetric measurements, electrochemical methods and Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-Ray analysis (EDX). The electrochemical assessments validated the findings from the gravimetric analysis and demonstrated that our inhibitor significantly modifies the electrochemical process mechanism at the B66/3% NaCl interface. The corrosion rate of bronze decreases with the inhibitor's presence, and its inhibitory effectiveness amplifies with higher concentrations, reaching an efficiency of 86 % at 750 ppm. The mechanism of metallic copper and corrosion Acemannan inhibitor was explored through DFT studies and molecular dynamics simulation

Antioxidant and Antimicrobial Activity of Polyphenols Extracted after Adsorption onto Natural Clay “Ghassoul”

Natural polyphenols contained in olive mill wastewaters (OMW) have been usually associated with great bioactive properties as “antioxidants”. In this work, we recovered the polyphenols after adsorption onto natural clay “ghassoul” by different solvents: water, ethyl acetate, and methanol (PPW, PPA, and PPM, respectively) to avoid environmental pollution. Also, we tested the antioxidant activity of the extracted polyphenols by two methods: 1,1-diphenyl-2-picrylhydrazyl (DPPH) and total antioxidant capacity (TAC). Then, we analyzed antimicrobial activity by the microdilution technique to determine at the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The OMW of the Fez-Meknes region has a very acidic pH, considerable amounts of mineral matter, and a high concentration of polyphenols and organic content. The results of the test from DPPH showed good antiradical potential for polyphenols extracted with water, but the TAC showed an important capacity for all extracts unless PPA. The antibacterial activity is not the same on the four bacteria studied (Escherichia coli, Salmonella sp, Staphylococcus aureus, and Enterococcus faecalis), and all extracts inhibit most tested germs that do not have the same MIC and the same sensitivity. Only the PPW showed the minimum bactericidal concentration (MBC) that is equal to 0.290 mg/mL for Salmonella sp and Staphylococcus aureus, which confirms that the extraction by water of the adsorbed polyphenols is an original solution to recover the polyphenols and also to obtain a natural phenolic antioxidant which can be used in the pharmaceutical, nourishment, and cosmetic industry