The propensity for adherence to solid surfaces of asphaltenes, a complex solubility class of heteropolycyclic aromatic compounds from the heavy fraction of crude oil, has long been the root cause of scale deposition and remains an intractable problem in the petroleum industry. Although the adhesion is essential to understanding the process of asphaltene deposition, the relationship between the conformation of asphaltene molecules on mineral substrates and its impact on adhesion and mechanical properties of the deposits is not completely understood. To rationalize the primary processes in the process of organic scale deposition, here we use atomic force microscopy (AFM) to visualize the morphology of petroleum asphaltenes deposited on model mineral substrates. High imaging contrast was achieved by the differential adhesion of the tip between asphaltenes and the mineral substrate. While asphaltenes form smooth continuous films on all substrates at higher concentrations, they deposit as individual nanoparticles at lower concentrations. The size, shape, and spatial distribution of the nanoaggregates are strongly affected by the nature of the substrate; while uniformly distributed spherical particles are formed on highly polar and hydrophilic substrates (mica), irregular islands and thicker patches are observed with substrates of lower polarity (silica and calcite). Asphaltene nanoparticles flatten when adsorbed on highly oriented pyrolytic graphite due to π-π interactions with the polycyclic core. Force-distance profiles provide direct evidence of the conformational changes of asphaltene molecules on hydrophilic/hydrophobic substrates that result in dramatic changes in adhesion and mechanical properties of asphaltene deposits. Such an understanding of the nature of adhesion and mechanical properties tuned by surface properties, on the level of asphaltene nanoaggregates, would contribute to the design of efficient asphaltene inhibitors for preventing asphaltene fouling on targeted surfaces. Unlike flat surfaces, the AFM phase contrast images of defected calcite surfaces show that asphaltenes form continuous deposits to fill the recesses, and this process could trigger the onset for asphaltene deposition.

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.langmuir.7b00866DOI Listing

Publication Analysis

Top Keywords

mineral substrates
12
adhesion mechanical
12
mechanical properties
12
asphaltene
10
asphaltene nanoparticles
8
model mineral
8
surfaces asphaltenes
8
scale deposition
8
asphaltene deposition
8
asphaltene molecules
8

Similar Publications

Effects of different water and fertilizer treatments on the matrix properties and plant growth of tailings waste.

Sci Rep

January 2025

Land and Resources Survey Center, Hebei Provincial Geology and Mineral Exploration and Development Bureau, Shijiazhuang, 050081, China.

Vegetation ecological restoration technology is widely regarded as an environmentally sustainable and green technology for the remediation of mineral waste. The appropriate ratio of amendments can improve the substrate environment for plant growth and increase the efficiency of ecological restoration. Herbs and shrubs are preferred for vegetation restoration in abandoned mines because of their rapid establishment and easy management.

View Article and Find Full Text PDF

VG@nAu-based fluorescent biosensor for grading Alzheimer's disease by detecting P-tau181 protein in clinical samples.

Anal Chim Acta

February 2025

Institute for Advanced Study (IAS), College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, 518060, China. Electronic address:

Background: Alzheimer's disease (AD) is a neurodegenerative disorder with a very long duration, posing a serious threat to people's life and health. To date, no medicine that can cure or reverse the disease has been developed or reported, so early diagnosis and timely intervention are essential. The concentration of Phosphorylated tau181 (P-tau181) in blood has been approved by FDA as a standard for assisting clinical diagnosis of AD.

View Article and Find Full Text PDF

Larch wood, a prevalent cultivation medium for , has yet to be scrutinized concerning the differential impacts of sterilized and non-sterilized substrates on the growth and development of this fungus. Our present investigation sought to elucidate these effects in a forest-like environment. After larch wood segments were sun-dried, they were divided into two groups; one group was bagged and autoclaved, while the other group was bagged without any treatment.

View Article and Find Full Text PDF

Calcium phosphates are often used for biomedical applications. Hydroxyapatite, for example, has a wide range of applications because it mimics the mineral component of natural bone. Widespread interest in the catalytic properties of ceria is due to its use in automotive catalytic converters.

View Article and Find Full Text PDF

Preparation of CHS-FeO@@ZIF-8 peroxidase-mimic with an ultra-thin hollow layer for ultrasensitive electrochemical detection of kanamycin.

Mikrochim Acta

January 2025

Key Laboratory for Palygorskite Science and Applied Technology of Jiangsu Province, National & Local Joint Engineering Research Center for Mineral Salt Deep Utilization, Huaiyin Institute of Technology, Huaian, 223003, P. R. China.

A highly sensitive and selective electrochemical biosensor was developed for the detection of kanamycin using a core-hollow-shell structured peroxidase-mimic nanozyme, CHS-Fe₃O₄@@ZIF-8. The synthesized CHS-FeO@@ZIF-8 was characterized with scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. It was found that the CHS-FeO@@ZIF-8 exhibits excellent peroxidase-like activity due to  its ultra-thin hollow layer.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!