The use of different types of chemicals in upstream oilfield operations is critical for optimizing the different operations involved in hydrocarbon exploration and production. Surfactants are a type chemical that are applied in various upstream operations, such as drilling, fracturing, and enhanced oil recovery. However, due to their nonbiodegradability and toxicity, the use of synthetic surfactants has raised environmental concerns. Natural surfactants have emerged because of the hunt for sustainable and environmentally suitable substitutes. This Review discusses the role of natural surfactants in upstream operations as well as their benefits and drawbacks. The Review discusses the basic characteristics of surfactants, their classification, and the variables that affect their performance. Finally, the Review examines the possible applications of natural surfactants in the upstream oil sector and identifies areas that require further research.
Cr(vi) is a heavy metal with a high toxicity level. Many levels of Cr(vi) in the environment are above the established quality standards. The membrane filtration method is a technique that can be used to reduce Cr(vi) levels because it is more effective and efficient compared to other methods. In this research, the ability of a PES membrane integrated with boehmite nanoparticles coated with polyphenolic compounds from Samanea saman bark extract (mixed matrix hollow fiber membrane PES/B-polyphenol) was studied in reducing Cr(vi) levels. The Cr(vi) removal carried out in this research used a membrane module, so test conditions were obtained that were similar to actual conditions. XRD, FTIR, PSA, tensile strength, and SEM-EDS characterization were carried out to study the characteristics of the membrane and nanofiller. The XRD diffractogram shows a specific peak for boehmite at 2θ = 14°. The results of FTIR characterization of B-polyphenols also identified the presence of Al-O functional groups at wave numbers 733, 603, 474 cm-1 for nanofillers and OH, C[double bond, length as m-dash]C, C-O, and C[double bond, length as m-dash]O functional groups for PES/B-polyphenol membranes. Based on SEM-EDS and tensile strength tests, it was observed that the Young's modulus value of the membrane was 56.67 MPa and had a porous surface that was evenly distributed. Mixed matrix hollow fiber membrane PES/B-polyphenols that have been fabricated can reduce Cr(vi) levels up to 92.12%. Mixed matrix hollow fiber membrane PES/B-polyphenols have a water flux 14.1 L m-2 h-1 with porosity is 85.3% and the contact angle formed between the membrane surface and water is 58-32°. Based on the results obtained, this mixed matrix hollow fiber membrane PES/B-polyphenol has potential to be applied on a larger scale regarding its application to reduce Cr(vi) levels.
The broader objective of this study is to identify natural materials that might inhibit the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We have focused on stingless bee honey, which has a unique taste that is both sweet and sour and sometimes bitter. We screened 12 samples of honey from 11 species of stingless bees using an angiotensin-converting enzyme 2 (ACE2)-spike protein-binding assay and phytochemical analysis. Ten of the samples showed inhibition above 50% in this assay system. Most of the honey contained tannins, alkaloids, flavonoids, triterpenoids, carotenoids and carbohydrates. Our findings in this in vitro study showed that honey from stingless bees may have a potent effect against SARS-CoV-2 infection by inhibiting the ACE2-spike protein-binding.
In the search for potent bioactive compounds derived from medicinal plants, Garcinia parvifolia from East Kalimantan has demonstrated significant bioactivity consistent with established scientific criteria. Bioassay-guided isolation of the fruit extract resulted in two new depsidones named methyl garcidepsidone B (1) and parvifoliricodone A (6), two known analogues, a phloroglucinol, and a furfural derivative. Their structures were determined by spectroscopic techniques. The isolated compounds were subjected to assessments for their potential antidiabetic effects through an α-glucosidase inhibition assay, anti-tyrosinase activity, and antioxidant properties. Out of the isolated compounds, methyl garcidepsidone B (1) was the most potent inhibitor against α-glucosidase compared with acarbose as a positive standard. In the antioxidant assay, all isolated compounds showed significant free radical scavenging activity against ABTS, with the exception of compound 4. Regarding tyrosinase inhibitory activity, all isolated compounds exhibited low enzyme inhibition activity. Additionally, in silico molecular docking studies showed that compounds 1-3 exhibited favorable conformation and binding affinities within the enzymatic pockets of α-glucosidase. These findings indicate that the indigenous G. parvifolia fruit may serve as a natural source of antidiabetic, antioxidant, and anti-tyrosinase compounds, with potential for further pharmacological investigation.