Porous-activated carbons have drawn great attention due to their important role in COsub.2 capture. Ni(NOsub.3)sub.2/KOH, as co-catalysts under different temperatures, were studied to obtain porous ...graphitized carbon from Sargassum horneri feedstock. The results indicated that the properties of the porous graphitized carbon generated at 850 °C were greatly enhanced, showing a large specific surface area of 1486.38 cmsup.3·gsup.−1 with narrowly distributed micropores (~0.67 nm) and abundant functional groups, which endowed high COsub.2 uptake; moreover, the high COsub.2 uptake was mainly attributed to the synergistic effect of Ni(NOsub.3)sub.2 and KOH, both in chemical modification and pore formation. The fitted values of the four kinetic models showed that the double exponential model provided the best description of carbon adsorption, indicating both physical and chemical adsorption. It is worth noting that carbon could be reused four times in the adsorption/desorption procedure in this research with good stability. This work focuses on the high-value-added comprehensive utilization of macroalgae, which not only is important for high-performance adsorbent preparation but also has positive benefits for the development and utilization of macroalgae resources.
In this study, the triterpenoids in the leaves of Lactuca indica L.cv. Mengzao (LIM) were extracted via microwave-assisted ethanol extraction, and the optimum extraction conditions for triterpenoids ...were determined through single-factor experiments and the Box-Behnken method. The effects of three factors (solid-liquid ratio, microwave power and extraction time) on the total triterpenoids content (TTC) were evaluated. The TTC of different parts (roots, stems, leaves and flowers) of LIM in different growth stages was studied, and the scavenging effects of the highest TTC parts on DPPH, ABTS and hydroxyl free radicals were investigated. The results showed that the optimum extraction conditions for microwave-assisted extraction of total triterpenoids from LIM leaves were as follows: solid-liquid ratio of 1:20 g/mL; microwave power of 400 W; and extraction time of 60 min. Under these conditions, the TTC was 29.17 mg/g. Compared with the fresh raw materials, the TTC of the materials increased after freeze drying. The leaves of LIM had the highest TTC, and the flowering stage was the best time. The triterpenoids from the leaves had a strong ability to eliminate DPPH and ABTS free radicals, and the elimination effect of dried leaves was better than that of fresh leaves, while the elimination effect of hydroxyl free radicals was not obvious. The tested method was used to extract total triterpenoids from LIM using a simple process at low cost, which provides a reference for developing intensive processing methods for L. indica.
Abstract Circularity is a decisive corner stone of a sustainable use of raw materials. This has been recognized at global level and is pushed forward specifically in Europe and e.g., Japan. Based on ...intensive desk top research and interviews with experts from the zinc industry, information on secondary raw materials for zinc recovery was compiled. This paper comprises of an overview of zinc bearing wastes, residues, and by-products occurring in all stages of zinc mining, production, as well as first-use and end-use production. These materials are quantified and characterized, and ways of recycling are described. As a result, potentials for an increase of zinc recycling rates are identified. Mine tailings are a meaningful resource for zinc recovery. Industrial wastes occurring in zinc smelters, such as Jarosite, Goethite, and their likes are in the scope of research projects aiming at recycling zinc and other valuable metals. Residues, ashes, drosses, slags that are produced in first use operation of the zinc value chain, such as galvanizing, zinc die casting, or brass plants are recycled almost completely in Europe and in many other regions in the world. The biggest potential for increasing recycling rates for zinc still lies in steel mill dusts. Also, the majority of zinc die cast parts seem to end up in waste incineration and dump sites. This low end-of-life zinc recycling rate bears room for additional recycling opportunities via an improvement of the intelligent collection and sorting of waste and other innovative recycling processes utilizing residues from waste-to-energy plants.
Understanding how life on Earth might have originated is the major goal of origins of life chemistry. To proceed from simple feedstock molecules and energy sources to a living system requires ...extensive synthesis and coordinated assembly to occur over numerous steps, which are governed only by environmental factors and inherent chemical reactivity. Demonstrating such a process in the laboratory would show how life can start from the inanimate. If the starting materials were irrefutably primordial and the end result happened to bear an uncanny resemblance to extant biology — for what turned out to be purely chemical reasons, albeit elegantly subtle ones — then it could be a recapitulation of the way that natural life originated. We are not yet close to achieving this end, but recent results suggest that we may have nearly finished the first phase: the beginning.Recent developments in systems chemistry have shown how the molecular building blocks of life could have arisen from plausible prebiotic feedstocks. This Perspective argues that we remain a long way from a full picture and speculates on what pieces of the puzzle are still missing.
This study explores the potential for making lightweight bricks via the use of dry, pulverized spent mushroom materials (SMM) as a thermal insulator. There are five distinct replacement proportions ...of SMM that are used, and they range from 0% to 15% of the weight of the clay. The firing of the fabricated bricks at temperatures of 700, 800, and 900 °C led to the development of pores on the interior surface of the bricks as a consequence of the decomposition of SMM. The impact of SMM on the physicomechanical characteristics of fabricated bricks is assessed based on standard codes. Compressive strength, bulk density, and thermal conductivity decreased as the SMM content increased, reaching up to 8.7 MPa, 1420 kg/msup.3, and 0.29 W/mK at 900 °C and 15% substitution percentage. However, cold water absorption, boiling water absorption, linear drying shrinkage, linear firing shrinkage, and apparent porosity increased with the increase in SMM, reaching 23.6%, 25.3%, and 36.6% at 900 °C and 15% substitution percentage. In the study simulation model, there was a significant improvement in energy consumption, which reached an overall reduction of 29.23% and 21.49% in Cario and Jazan cities, respectively.
The gasification kinetics of semi-coke are an important research topic in the gasification process of semi-coke. The evolution of the pore structure is one of the most important factors affecting the ...gasification rate of semi-coke. In this paper, the pore fractal growth model was established based on the principle of pore fractal growth and the Sierpinski sponge structure. Three kinds of semi-coke raw materials were used to prepare porous carbon with different degrees of gasification. Combined with the TG curves of raw materials, the gasification kinetics based on the fractal model were verified. The curves of the gasification reaction rate and the specific surface area as a function of carbon conversion were consistent with the random pore model and experimental data, which verified the feasibility of the model. The pore fractal dynamic model could predict the change in the pore structure with carbon conversion during semi-coke gasification, so as to reveal the kinetic law of carbon gasification.
The production of ultra-pure raw material is a crucial step to ensure the required background level in rare event searches. In this work, we establish an innovative technique developed to produce ...high-purity (99.999%) granular zinc. We demonstrate the effectiveness of the refining procedure by measuring the internal contaminations of the purified zinc with a high-purity germanium detector at the Laboratori Nazionali del Gran Sasso. The total activity of cosmogenic activated nuclides is measured at the level of a few mBq/kg, as well as limits on naturally occurring radionuclides are set to less than mBq/kg. The excellent radiopurity of the zinc sample allows us to search for electron capture with positron emission and neutrinoless double electron capture of Formula omittedZn, setting the currently most stringent lower limits on their half-lives, Formula omitted (90% CI), and Formula omitted (90% CI), respectively.
The structure of Mnsub.3Osub.4 with an octahedron structure was similar to that of LiMnsub.2Osub.4, and the lithium manganate prepared with it had good electrochemical performance. During the ...preparation of octahedron Mnsub.3Osub.4, the effects of the pH regulator, temperature, and reaction pH on its morphology, specific surface area, and other properties were studied in this paper. LiMnsub.2Osub.4 was prepared from Octahedron Mnsub.3Osub.4 obtained by using better technology. The effects of calcination time and temperature on the physicochemical and electrochemical properties of LiMnsub.2Osub.4 were studied. The research results indicated that the optimal synthesis conditions for Mnsub.3Osub.4 were as follows: ammonia water was used as a pH regulator and complexing agent, reaction pH was 8, reaction temperature was 80 °C, reaction time was 12 h, and oxygen flow rate was 3 L∙minsup.−1. The LiMnsub.2Osub.4 synthesized had a good octahedron morphology when the calcination temperature was 800 °C and the calcination time was 10 h. The first discharge-specific capacity was 121.9 mAh∙gsup.−1 at a current density of 0.2 C, the discharge-specific capacity was 114.1 mAh∙gsup.−1 after 100 cycles, and the capacity retention rate was 93.6%. Therefore, the lithium manganate prepared by using octahedron manganous oxide had good electrochemical reversibility and a good application prospect.
Preparing submicron and nanoscale phosphors with good optical properties for practical applications is a challenging task for current inorganic long afterglow luminescent materials. This study ...utilized commercialized SrAlsub.2Osub.4:Eusup.2+, Dysup.3+ phosphors (SAOED) as raw materials and employed solvents with lower polarity or non-polar solvents for dynamic solvothermal treatment. The commercialized phosphor’s overall average particle size was reduced from 42.3 μm to 23.6 μm while maintaining the fluorescence intensity at 91.39% of the original sample. Additionally, the study demonstrated the applicability of the dynamic solvothermal method to most other commercialized inorganic phosphors. The experiment produced a high-brightness nano-sized phosphor with a yield of 5.64%. The average diameter of the phosphor was 85 nm, with an average thickness of 16 nm. The quantum efficiency of the phosphor was 74.46% of the original sample. The fingerprint imaging results suggest that the nano-sized phosphors have potential for practical applications.
We investigated the distribution patterns and evaluated the average contents of trace elements in the ksub.7 seam of the Karaganda coal basin in Central Kazakhstan. This paper presents the results of ...studying the geochemistry of 34 elements in 85 samples of the ksub.7 seam. The study employed a suite of advanced high-resolution analytical methods, including atomic emission spectrometry with inductively coupled plasma (ICP–OES) and mass spectrometry with inductively coupled plasma (ICP–MS), along with their processing and interpretation. It was determined that the concentrations of trace elements in the ksub.7 seam are primarily associated with lithophile elements, revealing high concentrations of Li, V, Sc, Zr, Hf, and Ba. Additionally, increased concentrations of Nb, Ta, Se, Te, Ag, and Th were observed compared to the coal Clarke. Specific Nb(Ta)–Zr(Hf)–Li mineralization accompanied by a group of associated metals (Ba, V, Sc, etc.) was identified. The study revealed lateral and vertical heterogeneity of the rare elements’ distributions in coals, attributed to the formation dynamics of the coal basin. A correlation between Li and Alsub.2Osub.3 with a less positive relationship with Ksub.2O suggests the affinity of certain elements (Li, Ta, Nb, and Ba) to kaolinite. Clay layers showed increased radioactivity, with Th—13.2 ppm and U—2.6 ppm, indicating the possible presence of volcanogenic pyroclastic rocks characterized by radioactivity. Taken together, these data reveal the features of the rock composition of the source area, which is considered a mineralization source. According to geochemical data, it was found that the source area mainly consists of igneous felsic rocks, indicating that the formation occurred under conditions of a volcanic arc. This study’s novelty lies in estimating the average trace elements in the ksub.7 seam, with elevated concentrations of certain elements that suggest promising prospects for industrial extraction from coals and coal wastes. These findings offer insights into considering coal as a potential source of raw material for rare metal production, guiding the industrial processing of key elements within coal. The potential extraction of metals from coal deposits, including from dumps, holds significance for industrial and commercial technologies, as processing critical coal elements can reduce disposal costs and mitigate their environmental impact.
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