Study of Thermally Expanded Graphite for Rehabilitation of Oil-Polluted Water Ecosystems

The properties of sorbent on the basis of thermoexplite (STRG) obtained from the engineering center of IngSU "Development of modified sorbation materials" have been investigated. This sorbent is proposed to be used in the elimination of oil spills and products of its processing from the water surface. The porosity of the STGR was analyzed using a mercury porosimeter Pascal 140 and 240 Evo. It is shown that the investigated sample is a volumetric porous tool with a specific pore volume of 35.5 cm3/g. It is found that the available porosity is more than 97.2%. The pore size distribution was studied. Based on the data of the porous system, research on the sorption of oil and oil products by this sorbent. Shown is the high efficiency of STRG in cleaning the water mirror from oil and oil products. The main properties of oil sorbents have been investigated.

Pore Structure Regulation and Electrochemical Performance Characterization of Activated Carbon for Supercapacitors

In order to achieve the purpose of regulating the pore structure characteristics of activated carbon by adjusting the experimental parameters, the effects of carbonization temperature, carbonization time, pre-activation temperature, pre-activation time and impregnation time on the pore structure of sargassum-based activated carbon (SAC) are studied by orthogonal experiment. The gravimetric capacitance of SAC and the relationship between the gravimetric capacitance and specific surface area are also studied. The results show that the SACs prepared at all experimental conditions have developed pore structure and huge specific surface area, reaching 3,122 m2/g. The pore size of SAC is almost all within 6 nm, in which the micropores are mainly concentrated in 0.4–0.8 nm, the mesopores are mainly concentrated in 2–4 nm, and the number of micropores is significantly higher than that of mesopores. During the preparation of SAC, the effect of carbonization temperature on the specific surface area and specific pore volume of SAC is very significant. The effect of carbonization time on the specific surface area of SAC is significant, but the effect on specific pore volume can be ignored. The effects of pre-activation temperature, pre-activation time, and impregnation time on specific surface area and specific pore volume of SAC can be ignored. In addition, SACs show good gravimetric capacitance performance as electrode material for supercapacitors, which can significantly increase the capacitance of supercapacitors and thus broaden their applications. The gravimetric capacitance and specific surface area of SACs show a good linear relationship when the activated carbons have similar material properties and pore size distribution.

Micro-Pore Reservoir Spaces and Gas-Bearing Characteristics of the Shale Reservoirs of the Coal Measure Strata in the Qinshui Basin

To study the exploration potential of the Carboniferous-Permian transitional shale reservoirs in the Qinshui Basin, the Y5 well was selected as the research object, and experiments including organic geochemical tests, microscopic observations, scanning electron microscopy, X-ray diffraction analysis, high-pressure mercury intrusion, methane isothermal adsorption, and low-temperature nitrogen adsorption were carried out to analyse the physical properties of the shale reservoirs of interest. The results show that (1) The organic matter type of the samples is type III, the total organic carbon contents range from 0.27% to 20.52% (avg. 3.15%), the RO values are between 2.45% and 3.36% (avg. 2.86%), and the Tmax values range from 311.00 °C to 575.20 °C (avg. 493.31 °C). These results indicate that the organic matter in the study area is abundant and has experienced a high degree of thermal evolution. (2) The brittleness index is low (avg. 43.81%), and the shale pores in the study area are well developed. The pores contain organic matter-hosted pores, intraparticle pores, interparticle pores, and micro-cracks. (3) The methane isotherm adsorption average contents of the two samples are 0.2968 m3/t and 1.0824 m3/t, and the average contents of the on-site desorbed gas content and measured total gas content are 0.55889 m3/t and 0.8624 m3/t, respectively. (4) The kaolinite and illite contents have a significant negative effect on the specific surface area of the macro-pores and the specific pore volume of the meso-pores. The illite content is conducive to the development of the pore diameter and specific surface area of the meso-pores, and the quartz content has a positive correlation with the specific pore volume of the macro-pores. (5) The measured total gas content has a significant positive correlation with the total organic carbon and a weak positive correlation with the contents of quartz and illite, and the desorbed gas content shows the same correlations. This study demonstrates the physical properties, microscopic pore characteristics, and gas-bearing characteristics of shale reservoirs and their influencing factors in detail.

Acid Modification of Diatomite-Based Sorbents

In this work, the effect of acid pre-treatment (hydrochloric acid, HCl) and calcination of diatomite, a silicon dioxide-material from natural sources, was studied with the aim to obtain diatomite-based sorbents with specific physicochemical properties. For this, acid pre-treatments with HCl at different calcination conditions, namely HCl concentration (0.5, 1 M) and calcination temperatures (from 600 to 900 °C) were studied. Morphological features different from those of natural diatomite were obtained. It has been found that treatment of diatomite with 0.5 M HCl at 800 °C showed a specific pore volume of 0.008 cm3/g, and a specific surface area of 19.26 m2/g, while the treatment of diatomite with 1.0 M HCl showed a specific pore volume of 0.011cm3/g, and a specific surface area of 25.57 m2/g. The performance of the acid pretreatment of diatomite for adsorption of Pb ions from water was also studied.

Highly Efficient Adsorption of Anionic Dye on Acid-Treated Halloysite Nanotubes

The adsorption capability of eosin Y as a model anionic dye on natural halloysite nanotubes (HNTs) and sulfuric acid-treated HNTs as a function of acid treatment time (1 h, 3 h, and 5 h) was examined. Scanning electron microscopy revealed that natural HNTs had a very uniform surface, whereas acid-treated HNTs had a rough surface with structural defects, which increased with acid treatment time. The total specific pore volume and total surface area of the acid-treated HNTs increased due to formation of nanopores in the HNTs via dissolution of the inner AlO6 octahedral layer. With acid treatment, the surface ξ—potentials were positively shifted from −42.9 mV (for the natural HNTs) to −1.9, −3.0, and +1.2 mV after 1, 3, and 5 h, respectively. The adsorption amount (qe) of eosin Y on natural HNTs and the three acid-treated HNTs was 2.3, 125.5, 118.9, and 118.9 mg g−1, respectively, implying that the adsorption capacity of acid-treated HNTs is ~50 times higher than that of natural HNTs. In this study, we clearly demonstrated that acid-treated HNTs can be used as highly efficient nanomaterials for removal of dyes from wastewater containing anionic dyes.

Synergy of Parameters Determining the Optimal Properties of Coal as a Natural Sorbent

Selection of the optimal properties of coal as a natural sorbent, both as a sample collected from a seam or of the coal seam itself, requires various parameters to be determined and may not be based on the knowledge of metamorphism degree only. In order to improve the predictions of sorption capacity and the kinetics, analyses of correlation and multiple regression based on the results of laboratory studies were performed for 15 coal samples with various coal rank. The maximum vitrinite reflectance (R0) for low-rank coals was 0.78%–0.85%, and 0.98%–1.15% and 1.85%–2.03% for medium- and high-rank coals, respectively. Coal samples were subjected to technical and petrographic analysis. The gravimetric method was used to perform sorption tests using methane, in order to determine the sorption capacity and the effective diffusion coefficient for each of the coals. Pycnometric methods were used to determine the textural parameters of coals, such as the percentage porosity and specific pore volume. The studies were further supplemented with an evaluation of the mechanical properties of the coals, Vickers micro-hardness, and elastic modulus. This work shows that the statistical multiple regression method enables a computational model including the selected petrophysical parameters displaying synergy with the specific sorption property—capacity or kinetics—to be created. The results showed the usefulness of this analysis in providing improved predictions of the optimal sorption properties of coal as a natural sorbent.

Preparation and Characterization of Monodisperse Mesoporous SiO2 Microspheres Modified by Octaphenylpolyoxyethyiene

Monodisperse mesoporous SiO2 microsphere is a potential fine candidate carrier of dry powder inhalation, but large numbers of active surface hydrophilic hydroxyls enhance surface energy, hydrogen bonding and electrostatic force, environmental water adsorption and particle agglomeration. Conventional hydrophobic modification of surface hydroxyls, which is conducive to solve the above-mentioned disadvantages, will limit the loading of water-soluble drugs and the drug dissolution in water simultaneously. In this study, monodisperse mesoporous SiO2 microspheres were prepared as carrier and modified innovatively by amphiphilic modifier octaphenylpolyoxyethyiene and 3-aminopropyltriethoxysilane, particle diameter about 60 nm, mean pore size 21.4 nm, specific pore volume 0.95 cm3/g, and specific surface area 130 m2/g. Model drug pentoxyverine citrate was loaded by pressure infiltration and spray drying process, drug loading 8.24%, repose angle 34°, mass median aerodynamic diameter 1.03 μm, and more than 90% of drug could dissolve within 30 min both in water and organic solvents.