Aerospace magnetic material scraps are abundant in cobalt and nickel. Sulfuric acid leaching process is an efficient method for extracting them. But it is a non-selective process, a significant amount of iron dissolves in the solution. This study focuses on the selective removal of iron from this solution using the jarosite process. Eh-pH diagram of K-S-Fe-H2O system was established. Based on thermodynamic analysis, H2O2 is used to oxidize Fe2+ into Fe3+, achieving efficient and selective removal of iron from the solution containing cobalt and nickel. The optimal conditions are as follows: temperature 95°C, K2SO4 dosage coefficient 1.5, seed dosage 10 g/L, time 90 min, pH 1.76, and endpoint pH controlled at approximately 3. Under these conditions, the iron removal efficiency is above 99%, while the loss ratios of cobalt and nickel are below 2%. The product is characterized by XRD and SEM-EDS. Results indicate that the product is jarosite ((K,H3O)Fe3(SO4)2(OH)6), exhibiting an ellipsoid structure with the mean particle size in the range of 0.2-5.0 μm. Temperature, pH value and seed dosage significantly affect reaction rate, particle size and crystallinity, and K2SO4 dosage mainly affects reaction rate and the morphology of jarosite. The jarosite crystallization kinetics can be described by the Avrami equation, with an Avrami index (n) of approximately 2.5 and the apparent activation energy of 42.68 kJ/mol.

Here, a phenomenon of efficient oxygen exchange between a silicon surface and a thin layer of tin dioxide during chemical vapor deposition is presented, which leads to a unique Sn:SiO2 layer. Under thermodynamic conditions in the temperature range of 725-735 °C, the formation of nanostructures with volcano-like shapes in \"active\" and \"dormant\" states are observed. Extensive characterization techniques, such as electron microscopy, X-ray diffraction, synchrotron radiation-based X-ray photoelectron, and X-ray absorption near-edge structure spectroscopy, are applied to study the formation. The mechanism is related to the oxygen retraction between tin(IV) oxide and silicon surface, leading to the thermodynamically unstable tin(II)oxide, which is immediately disproportionate to metallic Sn and SnO2 localized in the SiO2 matrix. The diffusion of metallic tin in the amorphous silicon oxide matrix leads to larger agglomerates of nanoparticles, which is similar to the formation of a magma chamber during the natural volcanic processes followed by magma eruption, which here is associated with the formation of depressions on the surface filled with metallic tin particles. This new effect contributes a new approach to the formation of functional composites but also inspires the development of unique Sn:SiO2 nanostructures for diverse application scenarios, such as thermal energy storage.

High-grade heavy metal elements in copper slag (CS) are worth recovering. Unfortunately, the high viscosity of leaching solution, low leaching efficiency, difficult filtration and low separation efficiency of valuable components exist in the traditional sulfuric acid leaching process. In this study, the above problems are solved by sulfuric acid pretreatment + curing + water leaching. Moreover, iron, cobalt and copper ions in solution are separated by stepwise precipitation. The final iron, cobalt, copper and silicon recoveries are 99.01 %, 98.45 %, 93.13 % and 99.52 %, respectively. Thermodynamic calculations show that H4SiO4 can be converted to insoluble SiO2 to improve filtration properties under curing conditions of sulfur dioxide partial pressures of 10-20∼0 atm, oxygen partial pressures of 10-20∼0 atm and 400-600k. Simulation studies of the phase equilibria of the components of the leach solution by Visual MINTEQ showed that the oxidation of Fe2+ to Fe3+ is necessary for the removal of Fe2+ from the solution by precipitation. This study provides a new idea for the efficient utilization of CS.

Arsenic (As) contamination of surface water has become a global concern, especially for the third world countries, and it is imperative to develop advanced materials and an effective treatment method to address the issue. In this paper, iron doped ZIF-8@MXene (Fe-ZIF-8@MXene) was prepared as a potential adsorbent to effectively and simultaneously remove As(III/V) from wastewater. To investigate this, Fe-ZIF-8@MXene was characterized before and after the removal of mixed As(III/V). The results of Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), specific surface area (BET) and point of zero charge (pHpzc) showed that Fe-ZIF-8@MXene was prepared successfully and kept a stable structure after As(III) and As(V) adsorption. The particle size of Fe-ZIF-8@MXene was in the range of 0.5 μm to 2.5 μm, where its BET was 531.7 m2/g. For both contaminants, adsorption was found to follow pseudo-second-order kinetics and was best-fitted by the Langmuir adsorption model with correlation coefficients (R2) of 0.998 and 0.997, for As(III) and As(V), respectively. The adsorbent was then applied to remove As from two actual water samples, giving maximum removal rates of 91.07% and 98.96% for As(III) and As(V), respectively. Finally, removal mechanisms for As(III/V) by Fe-ZIF-8@MXene were also explored. During the adsorption, multiple complexes were formed under the effect of its abundant surface functional groups involving multiple mechanisms, which included Van der Waals force, surface adsorption, chemical complexation and electrostatic interactions. In conclusion, this study demonstrated that Fe-ZIF-8@MXene was an advanced and reusable material for simultaneous removal of As(III/V) in wastewater.

HIV-1 integration into the human genome is dependent on 3\'-processing of the viral DNA. Recently, we reported that the cellular Three Prime Repair Exonuclease 1 (TREX1) enhances HIV-1 integration by degrading the unprocessed viral DNA, while the integration-competent 3\'-processed DNA remained resistant. Here, we describe the mechanism by which the 3\'-processed HIV-1 DNA resists TREX1-mediated degradation. Our kinetic studies revealed that the rate of cleavage (kcat) of the 3\'-processed DNA was significantly lower (approximately 2-2.5-fold) than the unprocessed HIV-1 DNA by TREX1. The kcat values of human TREX1 for the processed U5 and U3 DNA substrates were 3.8 s-1 and 4.5 s-1, respectively. In contrast, the unprocessed U5 and U3 substrates were cleaved at 10.2 s-1 and 9.8 s-1, respectively. The efficiency of degradation (kcat/Km) of the 3\'-processed DNA (U5-70.2 and U3-28.05 pM-1s-1) was also significantly lower than the unprocessed DNA (U5-103.1 and U3-65.3 pM-1s-1). Furthermore, the binding affinity (Kd) of TREX1 was markedly lower (∼2-fold) for the 3\'-processed DNA than the unprocessed DNA. Molecular docking and dynamics studies revealed distinct conformational binding modes of TREX1 with the 3\'-processed and unprocessed HIV-1 DNA. Particularly, the unprocessed DNA was favorably positioned in the active site with polar interactions with the catalytic residues of TREX1. Additionally, a stable complex was formed between TREX1 and the unprocessed DNA compared the 3\'-processed DNA. These results pinpoint the mechanism by which TREX1 preferentially degrades the integration-incompetent HIV-1 DNA and reveal the unique structural and conformational properties of the integration-competent 3\'-processed HIV-1 DNA.

Accurate models of muscle contraction are important for understanding both muscle performance and the therapeutics that enhance physiological function. However, models are only accurate and meaningful if they are consistent with physical laws. A single muscle fiber contains billions of randomly fluctuating atoms that on the spatial scale of a muscle fiber generate unidirectional force and power output. This thermal system is formally constrained by the laws of thermodynamics, and a recently developed thermodynamic model of muscle force generation provides qualitative descriptions of the muscle force-velocity relationship, muscle force generation, muscle force transients, and the thermodynamic work loop of muscle with a thermodynamic (not molecular) power stroke mechanism. To demonstrate the accuracy of this model requires that its outputs be quantitatively compared with experimentally observed muscle function. Here I show that a two-state thermodynamic model accurately describes the experimentally observed four-phase force transient response to both mechanical and chemical perturbations. This is the simplest possible model of one of the most complex characteristic signatures of muscle mechanics.

The copigmentation effect between malvidin-3-O-glucoside and caffeic acid was comprehensive inquiry on the model wine solution, theoretical simulation and real wine. Thermodynamic parameters were determined by UV/Visible spectroscopy and Isothermal titration calorimetry (ITC). Theoretical data were obtained employing a dispersion-corrected density functional approach. The effects in real wines were investigated by adding the caffeic acid during different fermentation periods. Results shown that the copigmentation reaction between caffeic acid and malvidin-3-O-glucoside is a spontaneous exothermic reaction driven by hydrogen bonding and dispersions forces. Computations show that the polyhydroxyl sugar moiety and phenolic hydroxyl groups are the key active sites. The addition of caffeic acid in post-alcohol fermentation samples evidences an improving color characteristics in the wine.

The present study evaluates the adsorption efficiency of low-cost carbonaceous adsorbents as fly ash (FA), saw dust biochar (SDB) (untreated and alkali - treated), live/dead pulverized white rot fungus Hypocrea lixii biomass encapsulated in sodium alginate (SA) against the commercially available activated carbon (AC) and graphene oxide (GO) SA beads for removal of benzene phenol derivatives - Bisphenol A (BPA)/triclosan (TCS). Amongst bi - and tri - composites SA beads, tri-composite beads comprising of untreated flyash - dead fungal biomass - sodium alginate (UFA - DB - SA) showed at par results with commercial composite beads. The tri - composite beads with point zero charge (Ppzc) of 6.2 was characterized using FTIR, XRD, surface area BET and SEM-EDX. The batch adsorption using tri - composite beads revealed removal of 93% BPA with adsorption capacity of 16.6 mg/g (pH 6) and 83.72% TCS with adsorption capacity of 14.23 mg/g (pH 5), respectively at 50 ppm initial concentration with 6 % adsorbent dose in 5 h. Freundlich isotherm favoring multilayered adsorption provided a better fit with r2 of 0.9674 for BPA and 0.9605 for TCS respectively. Intraparticle diffusion model showed adsorption of BPA/TCS molecules to follow pseudo - second order kinetics with boundary layer diffusion governed by first step of fast adsorption and intraparticle diffusion within pores by second slow adsorption step. Thermodynamic parameters (ΔH°, ΔS°, ΔG°) revealed adsorption process as exothermic, orderly and spontaneous. Methanol showed better desorbing efficiency leading to five cycles reusability. The phytotoxicity assay revealed increased germination rate of mung bean (Vigna radiata) seeds, sprinkled with post adsorbed treated water (0 h, 5 h and 7 h) initially spiked with 50 ppm BPA/TCS. Overall, UFA - DB - SA tri - composite beads provides a cost effective and eco - friendly matrix for effective removal of hydrophobic recalcitrant compounds.

The challenge of corrosion posed as a result of acidic sittings is considered as a major industrial concern, wherein ionic liquids serve as crucial in addressing the corrosive impacts on metals. In this study, five selected cyclic ammonium based ionic liquids were synthesized; IL-1MPyrBr, IL-1MPipBr, IL-2PyBr, IL-3MPyBr and IL-4MPyBr and their chemical structures were characterized using a variety of spectroscopic techniques (FT-IR, IH-NMR, 13C-NMR, Elemental analysis and thermal gravimetric analysis (TGA). Their corrosion inhibition efficiency was studied on carbon steel in 1 M HCl via different concentrations at 298 K using chemical and electrochemical parameters (PDP and EIS). DFT quantum parameters were computed, and the noted results were in complete compatible with the experimental. The synthesized ILs recorded excellent inhibition on the carbon steel corrosion in acidic media with increasing efficiency by increasing the inhibitor concentrations from 20 to 100 ppm. Different cations in the synthesized ILs affect the anti-corrosion effect and IL-3MPyBr showed the highest inhibition (ηR); 96.12% using the lowest concentration. Kinetic and thermodynamic considerations were studied and illustrated.

Molecularly imprinted ionic covalent organic framework nanocomposites (MI-IC-COF@SnO2) were prepared as potential adsorbents for the enhanced adsorption of nonsteroidal anti-inflammatory drugs (NSAIDs) from aqueous solution. The resulting material exhibited a pompon mum-like structure, featuring a large surface area, and well-defined mesopores. The presence of uniform positive ions within the three-dimensional skeleton of MI-IC-COF@SnO2 facilitated a rapid adsorption rate and high adsorption capacity for target analytes. Thermodynamic fitting revealed the adsorption process of NSAIDs to be feasible, endothermic, and spontaneous. Additionally, the adsorbent material exhibited respectable selectivity, as evidenced by imprinting factor values ranging from 2.8 to 6.7. Utilizing MI-IC-COF@SnO2 as the sorbent, a solid-phase extraction method coupled with high-performance liquid chromatography-ultraviolet detection (SPE-HPLC-UV) was developed and optimized. The proposed method demonstrated good linear range with determination coefficients of 0.998-0.999, and low limit of detection (0.18-1.35 µg L-1). Recoveries of NSAIDs in urine and river water samples were 78.1 %-106.1 %, with relative standard deviations lower than 12.5 %. This rapid and sensitive method enables the determination of NSAIDs at trace levels in complex matrices, providing reliable and reproducible results.