Research on Organic Nanopore Adsorption Mechanism and Influencing Factors of Shale Oil Reservoirs

The adsorption properties of shale oil are of great significance to the development of shale oil resources. This study is aimed at understanding the microscopic adsorption mechanism of shale oil in organic nanopores. Thus, a molecular model of organic micropore walls and multicomponent fluids of CO2, C4H10, C8H18, and C12H26 is constructed to investigate the adsorption pattern of multicomponent fluids in organic nanopores under different temperature and pore size conditions. The quantity and heat of adsorption are simulated with the Monte Carlo method, which has been used in previous studies for single-or two-component fluids. The results demonstrate that the ability of CO2 to displace various alkanes is different. Specifically, medium-chain n-alkanes are slightly weaker than light alkanes in competitive sorption, and long-chain n-alkanes are less conducive to competitive sorption. The higher the CO2 sorption ratio, the more the sorption sites occupied by CO2. Thus, it is the best replacement for shale oil. The adsorption quantity of carbon dioxide, n-butane, and n-octane in organic nanopores first increases and then decreases as temperature rises. Meanwhile, the adsorption quantity of n-dodecane decreases firstly and then increases. With the increase in the pore size, the adsorption quantity of carbon dioxide, n-butane, and n-octane in organic nanopores increases while the adsorption quantity of n-dodecane first increases and then decreases. Besides, the model with larger pore sizes is more sensitive to pressure changes in the adsorption of carbon dioxide and n-butane than the model with smaller pore sizes. The heat of adsorption is CO2, C12H26, C8H18, and C4H10 in descending order. All are physical adsorption. Moreover, the adsorption quantity of all four components mixed fluid in the organic matter nanopores is positively correlated with the heat of adsorption.

Rearranged Copolyurea Networks for Selective Carbon Dioxide Adsorption at Room Temperature

Copolyurea networks (co-UNs) were synthesized via crosslinking polymerization of a mixture of tetrakis(4-aminophenyl)methane (TAPM) and melamine with hexamethylene diisocyanate (HDI) using the organic sol-gel polymerization method. The subsequent thermal treatment of between 200 and 400 °C induced the sintering of the powdery polyurea networks to form porous frameworks via urea bond rearrangement and the removal of volatile hexamethylene moieties. Incorporating melamine into the networks resulted in a higher nitrogen content and micropore ratio, whereas the overall porosity decreased with the melamine composition. The rearranged network composed of the tetraamine/melamine units in an 80:20 ratio showed the highest carbon dioxide adsorption quantity at room temperature. The results show that optimizing the chemical structure and porosity of polyurea-based networks can lead to carbon dioxide adsorbents working at elevated temperatures.

Fabrication of three bio-adsorbents from different parts of rape straw

In this paper, three kinds of bio-adsorbents are fabricated from the different parts of rape straw, which are adsorbent-core, adsorbent-hull, and adsorbent-stalk, respectively. As the adsorbates, kerosene, paraffin, rapeseed oil and dibutyl phthalate are employed to evaluate the adsorption performance of the three kinds of bio-adsorbents. The results suggest that the three bio-adsorbents exhibit very different adsorption properties. The bio-adsorbent of adsorbent-core has much higher adsorption quantity to all of the four adsorbates than the other two bio-adsorbents. The adsorption mechanism of the three bio-adsorbents is investigated. The results illustrate that different bio-adsorbents own different micro-morphologies. The special micro-chamber structure is found in bio-adsorbent of adsorbent-core, which is seen as the main reason of owning excellent adsorption performance. The adsorption volume of unit mass (Va) was proposed to evaluate the intrinsic adsorption properties of the bio-adsorbents. The recovery performance of the bio-adsorbents by using of two different treatment methods is investigated. The effect of treatment on recovery rate is discussed.

Sorption of Sulfamethoxazole on Inorganic Acid Solution-Etched Biochar Derived from Alfalfa

The properties of alfalfa-derived biochars etched with phosphoric (PBC) or hydrochloric acid (ClBC) compared with raw materials (BC) were examine in this paper. SEM, FT-IR, XRD, BET and elemental analysis were performed to characterize the micromorphology and chemical structure comprehensibly. The results showed that the porous structure was enhanced, and surface area was increased via etching with inorganic acids. Batch adsorption experiments were performed for sulfamethoxazole (SMX) to biochars. The experimental data showed that modified biochars exhibited higher adsorption capacity for SMX, i.e., the adsorption quantity of ClBC and PBC had risen by 38% and 46%. The impact on pH values suggested that the physisorption, including pore-filling and electrostatic interaction, might be applied to original biochar. In addition, chemisorption also played a role, including hydrogen bonding, π-π electron donor acceptor interaction (π-π EDA), and so on. Furthermore, both pH and coexisting ions also had a certain effect on sorption. Enhancement of the electrostatic attraction between biochar and SMX might also account for the enhanced capacity of SMX at pH < 7, and coexisting ions could decrease the amount of SMX adsorbed onto biochars, mainly because of competition for adsorption sites.

Study of fractal based oxygen adsorption experiment of porous coal

Coal is China's main energy source and fuel. Coal spontaneous combustion is one of the most prominent issues that threaten the production safety of coal mining, storage, and transportation. In order to explore the factors affecting coal spontaneous combustion, we explored the pore structure characteristics of the coal based on the fractal theory, through the low-temperature liquid nitrogen adsorption experiment of coal. The fractal dimension of the coal sample was calculated, and the oxygen adsorption quantity of the same coal sample was obtained by using the physical adsorption experiment of coal. Experimental and fitting results showed that coal sample has obvious surface fractal dimension features and pore structure fractal features. Fractal dimension expressed coal oxygen adsorption well. In the meantime, the coal samples with lower fractal dimension, higher temperature, smaller porosity usually have less oxygen adsorption quantity. This research can not only enrich the study of oxygen adsorption in porous media such as coal, but also help to understand its spontaneous combustion mechanism in depth, thereby reducing the occurrence of spontaneous combustion disasters.

Preparation, microstructure and dye adsorption behavior of nanostructured FeTiO3 with a magnetic recovery capacity

Two different morphologies of FeTiO3 (nanopowders and nanosheets) were synthesized for the selective and efficient removal of Congo red and methylene blue dyes. The FeTiO3 samples were extensively performed by XRD, TEM, EDS, XPS, BET, UV-Vis, zeta potential, FTIR, and VSM analysis. The experimental data showed that FeTiO3 nanopowders (FTO-P) and FeTiO3 nanosheets (FTO-S) were mesoporous, and each had CR adsorption quantity of 110.68[Formula: see text]mg/g and 95.33[Formula: see text]mg/g, respectively. Although FTO-S had an excellent adsorption of 76.87[Formula: see text]mg/g for MB, FTO-P showed almost no MB adsorption. The studies indicated that adsorption conform to pseudo-second-order model. The electrostatic interactions and hydrogen bonding were deemed to the mainly adsorption mechanism. The magnetic properties of samples facilitated their recovery from solution after adsorption. The study shows that FeTiO3 was an excellent adsorbent due to its remarkable and selective adsorption performance and easy magnetic separation from aqueous solution.

Adsorption of Carbon Dioxide, Methane, and Nitrogen Gases onto ZIF Compounds with Zinc, Cobalt, and Zinc/Cobalt Metal Centers

ZIF-8, Co-ZIF-8, and Zn/Co-ZIF-8 are utilized in adsorbing nitrogen (N2), methane (CH4), and carbon dioxide (CO2) gases at temperatures between 25 and 55°C and pressures up to ~1 MPa. Equilibrium adsorption isotherms and adsorption kinetics are studied. The dual-site Langmuir equation is employed to correlate the nonisothermal adsorption equilibrium behavior. Generally, N2 showed the lowest equilibrium adsorption quantity on the three samples, whereas CO2 showed the highest equilibrium adsorption capacity. Amid the ZIF samples, the biggest adsorption quantities of N2 and CH4 were onto Zn/Co-ZIF-8, whereas the highest adsorption quantity of CO2 was on ZIF-8. The isosteric heats of adsorbing these gases on ZIF-8, Co-ZIF-8, and Zn/Co-ZIF-8 were examined. Moreover, the overall mass transfer coefficients of adsorption at different temperatures were investigated.

Novel Selective Depressant of Titanaugite and Implication for Ilmenite Flotation

This paper studies the effects of sodium polystyrene sulfonate (PSSNa) used as a depressant upon the separation of ilmenite from titanaugite through flotation when sodium oleate (NaOl) is used as a collector by performing single mineral flotation experiments. The depression mechanism of PSSNa on titanaugite flotation was studied by electrokinetic potential and adsorbed amount measurements together with FTIR and XPS detection. Single mineral flotation experiments show that PSSNa is a selective depressant for the separation of ilmenite and titanaugite via flotation with NaOl as the collector. The results of the adsorbed amount tests show that the biggest distinction is in terms of the amount of NaOl adsorbed on the surfaces of ilmenite and titanaugite; the amount is expanded from 2.28 × 10−7 to 9.34 × 10−7 mol/m2 when the dosage of PSSNa is 1 mg/L, as compared with no PSSNa, suggesting that PSSNa is a selective depressant when separating ilmenite and titanaugite through flotation. FTIR testing shows that chemisorption has occurred between the –SO3− groups of the molecular PSSNa and titanaugite surfaces. The results of further XPS testing reveal that PSSNa chemically interacts with Ca/Mg/Al/Fe on the titanaugite surface. The test results of FTIR in combination with XPS confirm that PSSNa stops NaOl from interacting with Mg, Fe, Al, and Ca on the titanaugite surface, and this outcome is the main reason for the widening of the adsorption quantity gap of NaOl on titanaugite and ilmenite surfaces, and titanaugite flotation is suppressed. The results of the comparison flotation testing on actual Panzhihua titanic iron ore (TiO2 grade: 15.63%) with titanaugite as the main gangue show that a better effect is obtained by replacing sodium silicate (SS) with PSSNa, and the recovery of TiO2 using PSSNa is higher than that when using sodium silicate. In a closed circuit flotation test, ilmenite concentrate is obtained with a TiO2 grade of 45.97% and a recovery of 76.32% by using PSSNa as a titanaugite depressant.

The chiral interfaces fabricated by d/l-alanine-pillar[5]arenes for selectively adsorbing ctDNA

In this paper, the d/l-AP5-interfaces are firstly fabricated by attaching d-alanine-pillar[5]arene and l-alanine-pillar[5]arene (d/l-AP5) onto the gold surface, and they exhibit a significantly different chiral influence on the morphology and the adsorption quantity of the adsorbed ctDNA molecules.