Evaluating crude oil distribution tendencies in a multi-phase aquatic system: Effects of oil type, water chemistry, and mineral sediment.

Planning for effective response to crude oil spills into water depends on evidence of oil behavior, including its tendency to become distributed throughout an aquatic system. An improved laboratory method is employed to quantitatively assess crude oil distribution among different layers that form after mixing within a multi-phase system of water and sediment. Mixtures of conventional crude oil or diluted bitumen with different water types in the presence or absence of mineral sediment are first mixed by a standard end-over-end rotary agitation protocol. After a settling period, each mixture's visibly distinct floating, surface oil (e.g., slick or emulsion), subsurface bulk water, and bottom layers are then separated. Finally, the masses of oil, water, and sediment constituting each layer are isolated, quantified, and compared. The novel results reveal how component properties affect oil distribution among layers to inform spill behavior models, risk assessments, and response plans, including applications of spill-treating agents.

COSMO-RS-Based Descriptors for the Machine Learning-Enabled Screening of Nucleotide Analogue Drugs against SARS-CoV-2.

Chemical similarity-based approaches employed to repurpose or develop new treatments for emerging diseases, such as COVID-19, correlates molecular structure-based descriptors of drugs with those of a physiological counterpart or clinical phenotype. We propose novel descriptors based on a COSMO-RS (short for conductor-like screening model for real solvents) σ-profiles for enhanced drug screening enabled by machine learning (ML). The descriptors' performance is hereby illustrated for nucleotide analogue drugs that inhibit the ribonucleic acid-dependent ribonucleic acid polymerase, key to viral transcription and genome replication. The COSMO-RS-based descriptors account for both chemical reactivity and structure, and are more effective for ML-based screening than fingerprints based on molecular structure and simple physical/chemical properties. The descriptors are evaluated using principal component analysis, an unsupervised ML technique. Our results correlate with the active monophosphate forms of the leading drug remdesivir and the prospective drug EIDD-2801 with nucleotides, followed by other promising drugs, and are superior to those from molecular structure-based descriptors and molecular docking. The COSMO-RS-based descriptors could help accelerate drug discovery for the treatment of emerging diseases.

Development and application of an amylopectin-graft-poly(methyl acrylate) solidifier for rapid and efficient containment and recovery of heavy oil spills in aqueous environments.

Effective oil spill preparedness and response are crucial to ensure environmental protection and promote the responsible development of the petroleum industry. Hence, interest in developing new approaches and/or improving existing oil spill response measures has increased greatly in the past decade. Solidifiers are an attractive and underutilized option to mitigate the effects of oil spills, as they interact with oil to contain the spill, prevent it from spreading, and facilitate its removal from the environment. In this work, we have synthesized an inexpensive and easy-to-make natural-based sorbent, a subclass of solidifiers. Our amylopectin-graft-poly(methyl acrylate) (AP-g-PMA) sorbent is highly oleophilic and hydrophobic, and selectively solidifies diluted bitumen and conventional crude oil from biphasic mixtures of oil and water. The complete solidification of conventional crude oil and diluted bitumen by the AP-g-PMA sorbent occurs within 8 and 32 min, respectively, and even a low solidifier-to-oil ratio of 4% w/w is sufficient to enable complete recovery of diluted bitumen. This innovative natural-based polymeric sorbent may be applied as a key component of oil spill response procedures, especially for heavy oils. The AP-g-PMA sorbent combines the biodegradability and non-toxicity of the amylopectin with the hydrophobicity and oleophilicity of the synthetic polymer poly(methyl acrylate).

Distributions of diluted bitumen and conventional crude oil in a range of water types.

Concern about the impacts that accidental discharge of under-investigated, heavy petroleum products may have on aquatic environments has prompted a comparative examination of the behaviours of diluted bitumen (DB) and light conventional crude (CC) oil in different water types. Distributions of oil among the water column and floating water-in-oil (w/o) emulsion are evaluated by a novel, reproducible procedure involving mixing oil with water, then separating, extracting, and quantifying the total absolute oil content of the water column via gravimetric and gas-chromatographic (high-temperature simulated distillation) analyses. The CC contents of water columns tend to be significantly greater than those of DB under comparable conditions, while the fraction of oil remaining afloat at the water's surface is greater for DB than for CC. The elucidated phase distribution patterns have important implications pertaining to the recoverability of these oils in the event of their release into aquatic environments, which serves to inform best practices for oil spill response. For both DB and CC, oil contents within water columns are the highest in waters of low salinity and high pH. Water contents of buoyant w/DB emulsions are significantly greater than those of w/CC emulsions after 60 min at rest, and are the highest in waters of low salinity and low pH. The effect of crude oil on the pH of water is also studied, and DB is found to have a greater effect than CC on water samples of varying initial pH.