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The seriousness of the greenhouse effect has forced more and more national and international institutions to actively develop carbon dioxide separation technologies, capture and storage technologies to control CO2 emissions. Among the many CO2 separation technologies, adsorption separation is a common method used in mixed gas separation technology at present. Pressure swing adsorption (PSA) has less regeneration time and less energy consumption, so is used more widely than temperature swing adsorption (TSA) and vacuum swing adsorption (VSA), which are the other two types of adsorption separation technologies. However, the adsorption capacity and adsorption selectivity of the existing adsorbents are poor, resulting in high energy consumption. This study is based on the results of industrial process simulation of flue gas from power plants [Sai et al. 2022], when the economic benefits of CO2 / N2 mixed gas PSA separation process are optimal, the adsorption capacity of MOF material is within a certain range. More than 4000 computation-ready, experimental metal-organic frameworks (CoRE MOFs) were calculated using Grand Canonical Monte Carlo (GCMC) high-throughput simulation, the PSA process of 1bar and a temperature of 298K, obtained 142 MOFs with potential performance. By comparing the optimal conditions required for CO2 capture in industrial simulation, we successively screened 14 and 11 kinds of MOF materials with good commercial application value and potential in industrial separation of CO2 suitable for four-stage and six-stage industrial separation respectively. It was found that materials containing Cu, Co, Ga, Mn, V, F, Br and Zn or nitrogen functional groups are more likely to adsorb and separate CO2. By calculated the adsorption properties of the MOFs at other industrial concentration of CO2 (1.25%, 2.1%, 2.55%, 3.5%, 7.5%, 20%, 30%) using the 142 kinds of good materials screened at 13% CO2 of flue gas from power plants, obtained the materials suitable for adsorption and separation at these ratios through the same screening conditions. When increasing the proportion of CO2, the number of selected materials meeting the requirements increased. The adsorption and separation performance of these materials with different proportions of CO2 were found to be outstanding and the amount of suitable material screened at these ratios was directly proportional to the CO2 content. These materials are likely to improve the economic efficiency of industrial CO2 adsorption and separation. [ABSTRACT FROM AUTHOR]

This article presents an innovative wall-climbing robot for detection on smooth wall surfaces, which consists of a vacuum adsorption system and adhesion belts, making the robot flexible and effectively steerable. Moreover, the detailed attachment mechanism is further analyzed for the climbing tasks. Safe operating conditions, kinematics, and dynamic model are derived, respectively, indicating that at least the adsorption force of 30 N and the motor torque of 2 N)m are required for stable climbing of the robot. Furthermore, the prototype of the wall-climbing robot is manufactured and the climbing abilities are tested on various wall surfaces showing that the maximum moving speed and corresponding load are 7.11 cm/s and 0.8 kg on the concrete exterior wall, 5.9 cm/s and 0.75 kg on the ceramic brick wall, 6.09 cm/s and 0.85 kg on the lime wall, and 5.9 cm/s and 1 kg on the acrylic surface, respectively, which demonstrates that the robot has high stability and adaptability. [ABSTRACT FROM AUTHOR]

Detrital ilmenite and its altered minerals are common in sandstone-hosted U deposits in the northern Ordos Basin, north China. Petrographic observation, SEM-EDS, EMPA, and LA-MC-ICP-MS were utilized to characterize the spatial relationship between altered ilmenite and the U minerals, and to investigate the U enrichment mechanism and alteration processes of ilmenite. Ilmenite was completely or partially altered to leucoxene and anatase along its rim and crack in ore-bearing sandstone. Framboidal and cement pyrite of BSR and TSR origin were identified around altered ilmenite. Two U phases closely related to altered ilmenite contain Ti-coffinite (I) and coffinite (II). These data indicate that ilmenite alteration and the associated processes of U enrichment can be divided into two stages. Stage one involves U pre-enrichment and adsorption, with stage two involving U enrichment via TiO2 (leucoxene and anatase) catalytic reduction. Ilmenite was altered into porous leucoxene that can adsorb U as uraniferous leucoxene and Ti-coffinite (I) and framboidal pyrite directly by reactions with H2S, produced by sulfate-reducing bacteria during synsedimentary and early diagenesis stages. Altered ilmenite can enrich U in the form of coffinite (II) through a catalytic reduction reaction which is triggered by β and γ radiation produced by previously adsorbed U during the uplift of ore-bearing bed in the Late Cretaceous period. In addition, cement pyrite can also reduce U6+ into U4+ which deposits on its surface in the form of coffinite (II). These results demonstrate a new mechanism, mediated by adsorption and catalytic reduction, to enrich U in sandstone-hosted U deposits. [ABSTRACT FROM AUTHOR]

Density functional theory method with full geometry optimization was used to study the adsorption of nitroamine (NHNO) on Al cluster. Both dissociative and nondissociative adsorption structures were predicted with different NHNO molecule orientations on Al cluster surfaces. In dissociative chemisorption, the main decomposition products of NHNO are O atom(s) and NHNO or NHN species. The O atoms being ruptured from the N-O bond form strong Al-O bonds with the neighboring Al around the adsorbed sites. In addition, the species obtained as a result of O atom elimination remains bonded to the surface. The largest adsorption energy is −737.66 kJ/mol when the NHNO molecule decomposes into two O atoms and a NHN fragment. For nondissociative adsorption, the seriously deformed nitroamine forms various N-O-Al bonding configurations with Al. The significant charge transfer occurs for all adsorption configurations. The most charge transfer is 2.068 e from the Al cluster surface to the fragments of the decomposed NHNO. The change of the electronic structures is obvious due to the adsorption or dissociation of NHNO molecule. Nitroamine readily oxidizes the aluminum surface of the Al cluster. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we prepared 3-aminopropyl-triethoxysilane (APTEOS) functionalized sodium alginate (SA) porous membrane adsorbent (APTEOS/SA) and tested its adsorption performance for removing of Cr(III) ions. The physico-chemical properties of the pristine and Cr(III) ions loaded APTEOS/SA were investigated by FT-IR, SEM-EDX, TG, AFM, and contact angle goniometer methods. To investigate the adsorption kinetics of Cr(III) ions onto this newly developed APTEOS/SA, we performed a batch of experiments under different adsorption conditions: solution pH, adsorbent dose, initial Cr(III) ion concentration, adsorption temperature, and contact time. The APTEOS/SA exhibited an encouraging uptake capacity of 90.0mg/g under suitable adsorption conditions. To study the mechanism of adsorption process, we examined the Lagergren pseudo-first-order and pseudo-second-order kinetic model, the intra-particular diffusion model, and the Crank model. Kinetics experiments indicated that the pseudo-first-order model displayed the best correlation with adsorption kinetics data. The Crank model showed that the intra-particle solute diffusion was the main rate-controlling step. Furthermore, our adsorption equilibrium data could be better described by the Freundlich equation. We also carried out consecutive adsorption–desorption experiments eight times to show that the APTEOS/SA has encouraging adsorption–desorption efficiencies. The results indicates that the prepared adsorbent is promising for using as an effective and economical adsorbent for Cr(III) ions removal. [Copyright &y& Elsevier]

To overcome major challenges of non-specific protein adsorption on nanoparticles for nanosensing and nanodiagnosis, an efficient method for robust chemical modification was developed to achieve excellent specific biorecognition and long-term stability in complex biomedia. This method is demonstrated by a highly specific and sensitive immunoassay (IA), using superparamagnetic nanospheres (NSs) with high magnetite content. The non-specific protein adsorption on the NSs was suppressed dramatically when modified with dual functional poly(carboxybetaine methacrylate) (polyCBMA) via surface-initiated atom transfer radical polymerization (SI-ATRP) and chemically grafted with antibodies of the β subunit of human chorionic gonadotrop (anti-β-hCG). The response to hCG of IA NSs with polyCBMA coatings was highly consistent in either phosphate-buffered saline (PBS) or 50% fetal bovine serum (FBS), which is far less variable than the response of the IA NSs without polyCBMA coatings. After all, a very robust platform for IA NSs with excellent specific biorecognition was obtained. It is expected that this method for nanoparticle modification could be widely used in ultrasensitive nanosensing and nanodiagnosis in the future. [ABSTRACT FROM AUTHOR]

Cetyltrimethylammonium bromide modified hydroxyapatite-bentonite composites (CTAB-HAp-Bent) were first synthesized by one-step hydrothermal method to test its U(VI) adsorption behaviors from phosphate‑carbonate coexisted solution. When pH = 8.0, U(VI) = 50 mg/L, [CO 3 T = 2 mmol/L, and [P] = 1.5 μmol/L, CTAB-HAp-Bent achieved the maximum q e values ~108.19 mg/g compared to HAp-Bent (~40.62 mg/g), CTAB-Bent (~81.70 mg/g) and HAp (93.90 mg/g). High alkalinity and ionic strength were unfavorable for U(VI) adsorption. Specifically, q e values increased with an increase of [P] up to 500 μmol/L and then changed little in the ranges from 500 μmol/L to 2000 μmol/L, whereas carbonate suppressed U(VI) adsorption in the whole studied [CO 3 T. Pseudo-second-order model, Langmuir isotherm and the thermodynamics deduced a spontaneous endothermic monolayer surface chemical adsorption process. Besides, characterization results suggested that the adsorption mechanisms were involved in the Br− anion exchange and -OH group coordination. Our present work optimized the U(VI) adsorption capacity of bentonite in eutrophic carbonate water, benefiting the research and design of potential modified clay or clay minerals materials for uranium recovery from eutrophic natural uranium-containing water. [Display omitted] • CTAB-HAp-Bent was synthesized by one-step hydrothermal method. • U(VI) adsorption was tested in phosphate-carbonate system for eutrophic water. • The composite displayed excellent adsorption performance. • Phosphate could promote U(VI) adsorption process. • Br− anion exchange and -OH group coordination dominated the mechanisms. [ABSTRACT FROM AUTHOR]