Determination of surface areas and textural properties of clay minerals

The Influence of Clay Structures to the Hygrothermal Component of the Indoor Environment

In this article, research on the sorption properties of clay materials in comparison with commonly used building materials is published. The topic is mainly focused on the dynamic sorption properties and their influence on the relative humidity in the indoor environment. The results of comparisons of clay structures, rammed earth panels, clay plaster, and unburned bricks, with commonly used building materials, concrete, lime plaster, and gypsum board are examined. Statistically evaluated results in the form of confidence intervals are presented and the rate of dynamic sorption is analyzed. It is clear from the results that clay materials have a positive effect on the rapid adsorption and desorption of air moisture in the interior of buildings. However, there are many variables, band not every clay material has such excellent sorption properties.

Catalytic Applications of Clay Minerals and Hydrotalcites

Clay minerals are the most abundant minerals on the surface of Earth [...]

Green Earth pigments aqueous dispersions: NMR relaxation rates dataset

The data presented here are related to the research paper entitled “Green Earth pigments dispersions: water dynamics at the interfaces”. The nuclear magnetic resonance (NMR) relaxometry data are provided for various aqueous Green Earth (GE) pigments dispersions with volume fraction spanning approximately from 0.1 to 0.5. For two of them (Cyprus GE and Bohemian GE), the NMR relaxation profiles from 10 kHz to 30 MHz (¹H frequency) is given for several temperatures spanning from 293 to 318K. In addition, the X-ray diffraction pattern is provided for France GE (Kremer pigments) for the identification of the main mineral component. The nitrogen gas isotherms are provided for Cyprus GE and Bohemian GE.

Green earth pigments dispersions: Water dynamics at the interfaces

HYPOTHESIS

The objective is to elucidate the multiscale dynamics of water within natural mixtures of minerals, green earth pigments that are mainly composed of phyllosilicates containing large amount of iron. In particular, the interaction of water with the different kinds of surfaces has to be probed. One issue is to examine the influence of surface type, basal or edge, on the dispersion quality.

EXPERIMENT

The study was carried out using ¹H variable field NMR relaxometry on various green earth pigment dispersions and concentrations. To analyse the data, a new analytical model was developed for natural phyllosilicates containing large amount of paramagnetic centres.

FINDING

The proposed theoretical framework is able to fit the experimental data for various samples using few parameters. It allows to determining water diffusion and residence times in complex phyllosilicate dispersions. Furthermore, it makes it possible to differentiate the contribution of the basal and edge surfaces and their respective surface area in interaction with water. Moreover, NMR relaxation profile reveals to be highly sensitive to the structural aspect of the phyllosilicates and to the accessibility of water to iron, hence allowing to discriminate clearly between two very similar phyllosilicates (glauconite and celadonite) that are difficult to distinguish by standard structural methods.

Chemical characterization and adsorption of oil mill wastewater on Moroccan clay in order to be used in the agricultural field

Oil mill wastewater (OMW) is the main liquid discharge from oil mills, it is considered as a dangerous pollutant due to its toxic chemical compounds which are unloaded directly in the environment without any treatment. The aims of this study were to evaluate the effectiveness of OMW adsorption on clay as a good method for the elimination of toxic chemical compounds and to study the application of treated OMW as an irrigation source in agricultural field. For this, Clay was collected from the city of Agourai (Meknes region, Morocco) and characterized by X-ray diffraction, X-ray fluorescence spectrometry, BET and FTIR analysis. Moreover, the treated OMW was analyzed using UHPLC-ESI-MS and the determination of total phenolic content (TPC) was also performed. However, the application of the treated OMW in agricultural field was performed by the determination of its effect on the germination of Lepidium sativum seeds (in vitro) and as a source of irrigation of Vicia faba plants (in situ). The results of this study showed that OMW had the following physicochemical characteristics: average pH of 4.88, TPC of 4.75 g/l, COD of 80 g/l, BOD5 of 18.72 g/l, conductivity of 16.05 cm-1, dry matter of 135.7 g/l and volatile matter of 58.7 g/l. The adsorption on clay had increased the pH from 4.88 to 6.14 and reduced significantly the organic matter (42% of COD and 57.4% of phenolic compounds). UHPLC-ESI-MS analysis showed the presence of a wide variety of organic compounds in OMW, with the appearance of new compounds after adsorption. Moreover, the use of treated OMW as a source of irrigation showed a significant effect on the germination of Lepidium sativum seeds and the growth of Vicia faba plants. From this study, we can conclude that the adsorption on clay is a good method for the treatment of OMW, which became non-toxic for environment and can be used as a source of irrigation in agricultural field.