Study of Henna (Lawsonia inermis) as Natural Corrosion Inhibitor for Aluminum Alloy in Seawater

Nanostructured CuO Thin-Film-Based Conductometric Sensors for Real-Time Tracking of Sweat Loss

Enhanced sweat sensors lead to real-time, sustained, noninvasive tracking of sweat loss, ensure insight into individual health conditions at the molecular level, and have obtained prominent interest for their hopeful implementations in customized health tracking. Metal-oxide-based nanostructured electrochemical amperometric sensing materials are the best selection for continuous sweat monitoring devices owing to their high stability, high-sensing capacity, cost-effectiveness, miniaturization, and wide applicability. In this research, CuO thin films have been fabricated by successive ionic layer adsorption and reaction technique (SILAR) with and without the addition of Lawsonia inermis L. (Henna, (LiL)) leaf extract (C₁₀H₆O₃, 2-hydroxy-1,4-naphthoquinone) with a high-sensitive and rapid response for sweat solution. Despite the pristine film being responsive to the 65.50 mM sweat solution (S = 2.66), the response characteristic improves to 3.95 for the 1.0% LiL-implemented CuO film. Unmodified, 1.0% LiL and 3.0% LiL-substituted thin-film materials assure considerable linearity with linear regression ranges, R², of 0.989, 0.997, and 0.998, respectively. It is noteworthy here that this research aims to determine an enhanced system that could potentially be implemented in real-life sweat-tracking administrations. Real-time sweat loss tracking capabilities of CuO samples was found to be promising. Derived from these outcomes, we concluded that the fabricated nanostructured CuO-based sensing system is a useful application for the continuous observation of sweat loss as a biological argument and compatibility with other microelectronic technologies.

Influence of Henna Extracts on Static and Dynamic Adsorption of Sodium Dodecyl Sulfate and Residual Oil Recovery from Quartz Sand

The application of surfactant flooding for enhanced oil recovery (EOR) promotes hydrocarbon recovery through reduction of oil-water interfacial tension and alteration of oil-wet rock wettability into the water-wet state. Unfortunately, surfactant depletion in porous media, due to surfactant molecule adsorption and retention, adversely affects oil recovery, thus increasing the cost of the surfactant flooding process. Chemical-based materials are normally used as inhibitors or sacrificial agents to minimize surfactant adsorption, but they are quite expensive and not environmentally friendly. Plant-based materials (henna extracts) are far more sustainable because they are obtained from natural sources. However, there is limited research on the application of henna extracts as inhibitors to reduce dynamic adsorption of the surfactant in porous media and improve oil recovery from such media. Thus, henna extracts were introduced as an eco-friendly and low-cost sacrificial agent for minimizing the static and dynamic adsorption of sodium dodecyl sulfate (SDS) onto quartz sand in this study. Results showed that the extent of surfactant adsorption was inversely proportional to the henna extract concentration, and the adsorption of the henna extract onto the quartz surface was a multilayer adsorption that followed the Freundlich isotherm model. Precisely, the henna extract adsorption on quartz sand is in the range of 3.12-4.48 mg/g (for static adsorption) and 5.49-6.73 mg/g (for dynamic adsorption), whereas the SDS adsorption on quartz sand was obtained as 2.11 and 4.79 mg/g at static and dynamic conditions, respectively. In the presence of 8000 mg/L henna extract, SDS static and dynamic adsorption was significantly reduced by 64 and 82%, respectively. At the same conditions, the residual oil recovery increased by 9.2% over normal surfactant flooding. The study suggests that the use of henna extracts as a sacrificial agent during SDS flooding could result in the reduction of static and dynamic adsorption of surfactant molecules on quartz sand, thus promoting hydrocarbon recovery from sandstone formations.

Oryza sativa plant extract in 15% hydrochloric acid as a green corrosion inhibitor on the surface of stainless steel 410

Fifteen percent hydrochloric acid (HCl) solutions are used for some cleaning processes in the petroleum industry. The use of such a corrosive medium is mainly responsible for the corrosion of the stainless steel (SS-410) vessels and pipings. In this study, the corrosion inhibiting properties of Oryza sativa plant extract (OSPE) from agricultural residues are investigated on SS-410 steel surfaces in a 15% HCl medium. Gravimetric analysis showed a maximum corrosion inhibition of 91.92% with 4 g/L OSPE in 15% HCl solution. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction studies confirmed the adsorption of OSPE on the SS-410 surface. The adsorption of OSPE on SS-410 followed the Langmuir adsorption isotherm, indicating the formation of a monolayer on the SS-410 surface. The theoretical study confirmed that the anticorrosive effect could be mainly related to the phytochemical 9,12,15-octadecatrienoic acid 2,3-dihydroxypropyl ester. Consequently, the OSPE containing this phytochemical shows an anticorrosive behavior on the SS-410 surface in an acidic 15% HCl solution.

POTENTIAL SUSTAINABLE ANTIOXIDANTS FOR NATURAL RUBBER: HENNA AND ITS MAJOR COMPONENTS

Unsaturated chain structure of natural rubber makes it a poor defense against thermo-oxidative aging. Synthetic antioxidants are commonly used in rubber compound recipes to prevent/retard aging of the rubber material during its service life. However, synthetic antioxidants cause some negative effects on human and environmental health; they tend to be replaced by natural alternatives. In this study, the short- and long-term antioxidant effects of henna and its basic active components, lawsone and gallic acid, have been investigated individually for natural rubber cured with semi-efficient sulfur vulcanization system. The composition of henna was determined by gas chromatography-mass spectrometry (GC-MS) analysis. Qualitative and quantitative analysis were performed using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) to highlight structural changes on aged vulcanizates. The authors attempted to correlate the suggested aging mechanism with rheological, mechanical, and morphological properties. Results showed that both lawsone and gallic acid were impressively successful regarding their anti-oxidation activity. In addition, henna, which contains a sufficient amount of lawsone and gallic acid, has been suggested as a competitive natural alternative to the common synthetic stabilization system for natural rubber, considering its sustainable commercial abundancy.

The Effect of Concentration of Lawsonia inermis as a Corrosion Inhibitor for Aluminum Alloy in Seawater

Lawsonia inermis also known as henna was studied as a corrosion inhibitor for aluminum alloy in seawater. The inhibitor has been characterized by optical study via Fourier transform infrared spectroscopy (FTIR). The FTIR proves the existence of hydroxyl and carbonyl functional groups in Lawsonia inermis. Aluminum alloy 5083 immersed in seawater in the absence and presence of Lawsonia inermis was tested using electrochemistry method, namely, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP). EIS and PP measurements suggest that the addition of Lawsonia inermis has caused the adsorption of inhibitor on the aluminum surface. The adsorption behavior of the inhibitor follow Langmuir adsorption model where the value of free energy of adsorption, -ΔG, is less than 40 kJ/mol indicates that it is a physical adsorption. Finally, it was inferred that Lawsonia inermis has a real potential to act as a corrosion inhibitor for aluminum alloy in seawater.

Volatile fatty acids produced by co-fermentation of waste activated sludge and henna plant biomass

Anaerobic co-fermentation of waste activated sludge (WAS) and henna plant biomass (HPB) for the enhanced production of volatile fatty acids (VFAs) was investigated. The results indicated that VFAs was the main constituents of the released organics; the accumulation of VFAs was much higher than that of soluble carbohydrates and proteins. HPB was an advantageous substrate compared to WAS for VFAs production; and the maximum VFAs concentration in an HPB mono-fermentation system was about 2.6-fold that in a WAS mono-fermentation system. In co-fermentation systems, VFAs accumulation was positively related to the proportion of HPB in the mixed substrate, and the accumulated VFAs concentrations doubled when HPB was increased from 25% to 75%. HPB not only adjust the C/N ratio; the associated and/or released lawsone might also have a positive electron-shuttling effect on VFAs production.

Enhanced azo dye removal in a continuously operated up-flow anaerobic filter packed with henna plant biomass

Effects of henna plant biomass (stem) packed in an up-flow anaerobic bio-filter (UAF) on an azo dye (AO7) removal were investigated. AO7 removal, sulfanilic acid (SA) formation, and pseudo first-order kinetic constants for these reactions (kAO7 and kSA) were higher in the henna-added UAF (R2) than in the control UAF without henna (R1). The maximum kAO7 in R1 and R2 were 0.0345 and 0.2024 cm(-1), respectively, on day 18; the corresponding molar ratios of SA formation to AO7 removal were 0.582 and 0.990. Adsorption and endogenous bio-reduction were the main AO7 removal pathways in R1, while in R2 bio-reduction was the dominant. Organics in henna could be released and fermented to volatile fatty acids, acting as effective electron donors for AO7 reduction, which was accelerated by soluble and/or fixed lawsone. Afterwards, the removal process weakened over time, indicating the demand of electron donation and lawsone-releasing during the long-term operation of UAF.

Enhanced reduction of an azo dye using henna plant biomass as a solid-phase electron donor, carbon source, and redox mediator

The multiple effects of henna plant biomass as a source of carbon, electron donor, and redox mediator (RM) on the enhanced bio-reduction of Orange II (AO7) were investigated. The results indicated that the maximum AO7 reduction rate in the culture with henna powder was ∼6-fold that in the sludge control culture lacking henna. On the one hand, AO7 reduction can be advantageously enhanced by the release of available electron donors; on the other hand, the associated lawsone can act as a fixed RM and play a potential role in shuttling electrons from the released electron donors to the final electron acceptor, AO7. The soluble chemical oxygen demand (SCOD) during each experiment and the FTIR spectra suggested that the weakened AO7 reduction along with the retention of henna powder might not be attributed to the lack of fixed lawsone but rather to the insufficiency of electron donors.