scholarly journals Correlation Study Between Minerals Composition and Porosity Evolution of Black Shale Under Different Oxidation Mechanisms

2020 ◽  
Author(s):  
Baolong Zhu ◽  
Jing Li ◽  
Qi Li
Keyword(s):  
Clay Minerals ◽  
Black Shale ◽  
Biological Effects ◽  
Correlation Study ◽  
Chemical Effect ◽  
Rock Surface ◽  
Porosity Evolution ◽  
Surface Areas ◽  
Oxidation Mechanisms ◽  
Biological Group

Abstract The correlation between rock minerals composition and porosity evolution is essential to black shale oxidation,chemical and biological effects may act different roles which is unclear. In present study, the acid solution and Acidithiobacillus ferrooxidans was applied to simulate the chemical and biological effects, the total organic carbon (TOC), pyrite and clay minerals content, porosity characteristics, micro-surfacemorphologyof black shale sampleswere employed to analyze the minerals-porosity correlation. Results showed that the chemical effect led to a greaterdecrease of pyrite and increase of clay minerals content than biological effect, which accompanied by a higherspecific surface areas and pore volume. These difference may attribute to the TOCcontent, which decreasedby acid erosion and led to the increase of macropores in chemical group, then promoted the minerals reactions; whereas the TOC content increased byattached and dead bacteria cell bodies on rock surface, led to the increase of micropores and less minerals reactions in biological group. It suggests that the correlation between minerals composition and porosity evolution is different in chemical and biological effects, is mainly due to the different alter trends of TOC content.

scholarly journals Action Time-Effect and Mechanism of Low-Calcium Fly Ash in Cement-Based Composites

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 681
Author(s):  
Na Yan ◽  
Qingqing Tang ◽  
Ying Zhang ◽  
Guowen Sun
Keyword(s):  
Fly Ash ◽  
Nitrogen Adsorption ◽  
Chemical Effect ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Degree Of Hydration ◽  
Surface Areas ◽  
Activity Effect ◽  
Low Calcium ◽  
Pore Size Distributions

This study was conducted in order to investigate when low-calcium fly ash plays a physical or chemical effect and what is the chemical effect proportion of low-calcium fly ash. Two types of low-calcium fly ash and quartz powder, with similar fineness as active and inert admixtures, were used as materials in this study. Under different water/binder ratios and hydration ages, the effects of the different types of admixtures and their dosages on the flexural and compressive strength of the composites were studied. X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen adsorption methods, in addition to an assessment of the degree of hydration of the fly ash, were employed to observe the hydration products at different ages, the microstructures of the hydration products, as well as their surface areas and pore size distributions. The results show that during the hydration period of 28 days, the low-calcium fly ash has a micro-aggregate filling physical effect. However, after 56 days, the hydration degree of fly ash begins to exceed 1%. This illustrates that the low-calcium fly ash has both the pozzolanic activity effect and micro-aggregate filling effect. In contrast, the low-calcium fly ash hydrated for 90 days is still dominated by the physical filling effect.

A rapid method for the estimation of rock surface areas

Hydrobiologia ◽  
2004 ◽  
Vol 517 (1-3) ◽  
pp. 133-136 ◽  
Author(s):  
M.J. McWhinnie ◽  
S.J. Chapman ◽  
A.C. Edwards ◽  
Y.E.M. Cook
Keyword(s):  
Rapid Method ◽  
Rock Surface ◽  
Surface Areas

The effect of weathering on rock wall erosion and rockfall generation at La Cornalle, Switzerland

2020 ◽  
Author(s):  
Li Fei ◽  
Marc-Henri Derron ◽  
Tiggi Choanji ◽  
Michel Jaboyedoff ◽  
Chunwei Sun
Keyword(s):  
Rock Mass ◽  
Monitoring Program ◽  
Time Lapse ◽  
Effect Of Temperature ◽  
Rock Surface ◽  
Rock Wall ◽  
Rock Face ◽  
Surface Areas ◽  
Thaw Cycle ◽  
Rock Temperature

<p>The weathering posing a significant influence on the rock wall retreat has been widely recognized. In this paper, multi-methods monitoring is designed to detect the erosion and rockfall activity on a rockslide cliff composed of marl-sandstone (maybe mixed with limestone) in Western Switzerland. The monitoring program includes weekly SfM and monthly LiDAR scanning measurements of rock cliff surface, hourly time-lapse imaging of the rock cliff, manual measurement of rock surface moisture, automated recordings of rock temperature and influencing meteorological factors (air temperature, humidity, wind, and precipitation) collected by a weather station. Sequential 3D Points Clouds acquired by LiDAR and SfM from December 2019 are used to visually identify the location of erosion and rockfall at monthly resolution. According to the rock wall structural analysis, the rock mass consists of a network of discontinuities mainly oriented nearly parallel and perpendicular to the direction of the layers. Some fractures are filled with calcite which might lead to a zone of weakness in the rock mass. During the field survey, we saw some calcite crystals covering on the rock block surface in the deposit area and exposed on rock cliff outcrop. We suppose that some rockfalls are generated along those discontinuities filled with calcite where the chemical reaction is active when there is constant water infiltrating during rainfall season. According to the preliminary panoramic thermal image of the cliff surface shot by DJI Mavic 2 Enterprise on 19 December 2019, some weathered and fresh surface areas show different temperatures in the same rock layers which suggest the thermal imaging monitoring may help us to identify the weathering spatial characteristics. In this study, we try first to reveal the effect of temperature variations (thermal stress) on crack deformation from rock temperature values extracted from thermal images and the deformation measured by the crack meter during 24h in winter and summer. Secondly, we explore the role of freeze-thaw cycle playing in the rock fall initiation and rock face erosion. Thirdly, we make clear the link between surface weathering spatial distribution and location of erosion, rockfalls. This provides a model of weathering and rockfall estimation.</p>

Interactions of pesticides with clays and layered double hydroxides: a review

Clay Minerals ◽  
2008 ◽  
Vol 43 (2) ◽  
pp. 155-175 ◽  
Author(s):  
J. Cornejo ◽  
R. Celis ◽  
I. Pavlovic ◽  
M. A. Ulibarri
Keyword(s):  
Clay Minerals ◽  
Layered Double Hydroxides ◽  
Water Contamination ◽  
Natural Ecosystems ◽  
Surface Areas ◽  
Natural Clays ◽  
Double Hydroxides ◽  
Soil And Water Contamination ◽  
Adsorbent Materials ◽  
Soil And Water

AbstractThe increasing presence of pesticides in natural ecosystems has stimulated research to look for improved adsorbent materials which can be used to remediate and prevent soil and water contamination by these compounds. Among the different materials that have been assayed as adsorbents of pesticides are natural clay minerals, particularly 2:1 phyllosilicates and their structurally complementary synthetic analogues layered double hydroxides (LDHs). The great interest in natural clays and LDHs as adsorbent materials is mainly related to the large specific surface areas associated with their layered structure, the ease with which they are obtained or synthesized, and the possibility of modifying their surfaces to increase their affinity for specific adsorbates. This review summarizes the adsorptive properties of natural clays and LDHs for pesticides and related organic compounds. Particular emphasis is given to the surface modification of clay minerals and LDHs with organic ions as a strategy to improve the efficiency of these materials as pesticide adsorbents. Potential applications of unmodified and modified clays and LDHs as adsorbents to prevent and remediate soil and water contamination by pesticides are also discussed.

scholarly journals Physico–Chemical Interaction between Clay Minerals and Albumin Protein according to the Type of Clay

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 396 ◽  
Author(s):  
Kim ◽  
Oh
Keyword(s):  
Circular Dichroism ◽  
Fluorescence Quenching ◽  
Conformational Change ◽  
Clay Minerals ◽  
Protein Denaturation ◽  
Chemical Interaction ◽  
Harmful Effect ◽  
Chemical Effect ◽  
Physico Chemical ◽  
Circular Dichroïsm

Clay minerals are widely utilized in pharmaceutical and dermatological sciences as a gastrointestinal medicine or skin remediation agent. In order to verify the feasibility of clays as an injection, pill, or topical agent, it is important to study their interactions with biological components, such as proteins. In this study, we utilized a protein fluorescence quenching assay and circular dichroism spectroscopy to evaluate general aspects of protein denaturation and conformational change, respectively. Three different clays; layered double oxide (LDO), montmorilonite (MMT) and halloysite nanotube (HNT), were treated with albumin and the physico-chemical effect on the protein’s conformation was investigated. MMT was shown to influence the conformational change the most, owing to the large accessible adsorption site. HNT showed meaningful circular dichroism (CD) band collapse as well as fluorescence quenching in the protein, suggesting a potential harmful effect of HNT toward the protein. Among the three tested clays, LDO was determined to affect protein structure the least in terms of three-dimensional conformation and helical structure.

In vitro biological effects of clay minerals advised as substitutes for asbestos

1995 ◽  
Vol 11 (5) ◽  
pp. 237-249 ◽  
Author(s):  
M. Governa ◽  
M. Valentino ◽  
I. Vison� ◽  
F. Monaco ◽  
M. Amati ◽  
...  
Keyword(s):  
Clay Minerals ◽  
Biological Effects

scholarly journals Hidden drivers of low-dose pharmaceutical pollutant mixtures revealed by the novel GSA-QHTS screening method

2016 ◽  
Vol 2 (9) ◽  
pp. e1601272 ◽  
Author(s):  
Ismael Rodea-Palomares ◽  
Miguel Gonzalez-Pleiter ◽  
Soledad Gonzalo ◽  
Roberto Rosal ◽  
Francisco Leganes ◽  
...  
Keyword(s):  
High Throughput Screening ◽  
Low Dose ◽  
Biological Effects ◽  
Screening Method ◽  
Ecological Impacts ◽  
Complex Mixtures ◽  
Chemical Effect ◽  
Integrated Analysis ◽  
Effect Assessment ◽  
Pharmaceutical Pollutants

The ecological impacts of emerging pollutants such as pharmaceuticals are not well understood. The lack of experimental approaches for the identification of pollutant effects in realistic settings (that is, low doses, complex mixtures, and variable environmental conditions) supports the widespread perception that these effects are often unpredictable. To address this, we developed a novel screening method (GSA-QHTS) that couples the computational power of global sensitivity analysis (GSA) with the experimental efficiency of quantitative high-throughput screening (QHTS). We present a case study where GSA-QHTS allowed for the identification of the main pharmaceutical pollutants (and their interactions), driving biological effects of low-dose complex mixtures at the microbial population level. The QHTS experiments involved the integrated analysis of nearly 2700 observations from an array of 180 unique low-dose mixtures, representing the most complex and data-rich experimental mixture effect assessment of main pharmaceutical pollutants to date. An ecological scaling-up experiment confirmed that this subset of pollutants also affects typical freshwater microbial community assemblages. Contrary to our expectations and challenging established scientific opinion, the bioactivity of the mixtures was not predicted by the null mixture models, and the main drivers that were identified by GSA-QHTS were overlooked by the current effect assessment scheme. Our results suggest that current chemical effect assessment methods overlook a substantial number of ecologically dangerous chemical pollutants and introduce a new operational framework for their systematic identification.

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