Theoretical Amount Research Articles

For elements-utilization regeneration of spent LiFePO4: Designed basic precursors for advanced polycrystal electrode materials

Spent lithium iron phosphate (LFP) is commonly recovered by hydrometallurgy to prepare Li2CO3 and FePO4, but suffering from long process and low value-added products. Hydrothermal method avoids element separation and regenerates LFP materials directly from leaching solution of spent LFP. However, it requires three-time the theoretical amount of lithium. In this study, using LiFePO4(OH) (LFPOH) as a medium, LFP materials were regenerated with theoretical amount of lithium in virtue of energetically favorable reaction of Li-ions into the internal structure. The formation mechanism of LFPOH and LFP materials were investigated, and advanced polycrystal LFP materials with fast ions-diffusion ability and high reversibility were obtained. The capacities of recovered LFP materials are 156.17 mAh g−1, 148.51 mAh g−1, 138.34 mAh g−1, 124.1 mAh g−1 at 0.2 C, 0.5 C, 1 C and 2 C, respectively and their capacity could be remained 139.92 mAh g−1 at 1 C with retention of almost 100 % after 200 cycles. Moreover, with the assistance of economic analysis, the designed regenerated path displayed considerable recycling value-potential, especially the reducing of Li-resources (from three-time to one-time). This study sheds light on designing polycrystal recovered LFP with help of basic medium, whilst provides an effective strategy for preparing high-performance LFP materials.

Quantitative myocardial blood flow distribution derived from CCTA and determination of myocardium at risk in the FAST TRACK CABG trial

Abstract Background In the anatomic SYNTAX score derived from invasive coronary angiography, the ischemic impact of each stenotic coronary segment is weighed with a fixed score based on the severity of luminal diameter narrowing and the theoretical amount of blood flow supplied to the myocardium(1). This method neither accounts for individual variation nor reflects the true extent of myocardium ischemia. Purpose We aim to provide a quantitative CT SYNTAX score derived from coronary computed tomography angiography (CCTA) with customized percent blood flow distribution to the myocardium supplied by each stenotic coronary segment to determine the myocardium at risk of ischemia. Methods Patients with 3VD and/or left main coronary artery disease (CAD) were included in the first-in-human FAST TRACK CABG trial and received surgical revascularization guided solely by CCTA and fractional flow reserve derived from CCTA (FFRCT). The recently reported anatomic CT-SYNTAX score was calculated for all cases. The FFRCT value and percent myocardial blood flow distribution(%MBF) were computed for all 16 SYNTAX score segments using the validated method of Keulards et al(2). On the pre-CABG CCTA, the segments located distal to the site where the FFRCT value dropped below 0.80 were considered at risk of ischemia, and the individual weight point per segment was calculated as 6×%MBF for each segment. The SYNTAX score derived from %MBF is compared to the anatomic and functional CT-SYNTAX score. Results Out of 114 patients enrolled, FFRCT and %MBF were analyzable in 106 patients. After excluding vessels with total occlusion, the coronary flow distribution between the right and left coronary systems was 20.5% vs 79.5%, respectively, similar to the 1:5 ratio in the anatomic SYNTAX score. The anatomic and functional CT-SYNTAX scores were 43.6 and 41.1, respectively. The average total %MBF per patient was 72.0(19.1)%, and the average SYNTAX score derived from %MBF was 38.0. There is a strong correlation between functional SYNTAX score and SYNTAX score derived from %MBF (Peason’s R=0.93). Passing-Bablock regression trends showed that the functional SYNTAX score slightly overestimated the SYNTAX score derived from %MBF (Figure 1). The coronary segment weight varied significantly per individual, especially in the presence of total occlusion. Overall, the fixed weight of the anatomic SYNTAX score is a good surrogate for the individualized weighing based on %MBF (Figure 2). Conclusion CCTA-derived %MBF enabled clinicians to quantify the individualized myocardium at risk of ischemia or injury in patients with severe CAD. Retrospectively, the fixed weight score used in the anatomical SYNTAX score appeared to be a robust surrogate for myocardial blood flow distribution.Figure 1Figure 2

B-335 Analytical Performance of the Novel EQA Material for Fecal Immunochemical Test for Hemoglobin

Abstract Background EQA (external quality assurance) program for FIT (fecal immunochemical test for hemoglobin) is performed in many countries, and its demand increases as FIT is widely used in organized colorectal cancer screening programs. The materials used in FIT EQA vary from buffer-based liquid control, and lyophilized stool, to material that mimics stool, artificial stool. We could not find ideal EQA material with hemoglobin uniformly contained, good stability of hemoglobin, and ease in use such as ready-to-use form. The merit to use material that simulates actual sample, stool, is not only to be compliant with ISO15189 but also to suit various methods and sampling devices in FIT. The development of artificial stool material has been awaited by laboratories using FIT to evaluate errors and precisions in specimen collection.We assessed the analytical performance of the new artificial stool developed in HECTEF (Health Care Technology Foundation) to evaluate this artificial stool material was suitable as an EQA material. We examined the following three points: 1) Sample collection, 2) Uniformity, and 3) Stability of hemoglobin. Methods 1) Sample collection: The material was collected with the sampling probes of OC-Auto Sampling Bottle 3 (Eiken Chemical) and the collection amount was calculated by comparing the weight before and after sampling the artificial stool. 2) Uniformity: The uniformity of hemoglobin was evaluated during production before and after bottling based on “Uniformity of dosage units” section of The Japanese Pharmacopoeia 18th edition, 2021. The material was sampled from 10 different points and hemoglobin concentrations were measured using OC-Sensor DIANA. The uniformity of hemoglobin between the vials was evaluated by calculating the CV from the average of hemoglobin concentrations from samples of three points from three vials. 3) Stability of hemoglobin: The materials stored under different temperature conditions were compared with the material stored frozen at -20 °C. Storage conditions were at refrigeration for 20 months, at 30 °C for 1 month, and freeze-thawing for five times. Evaporation from the material was evaluated by weighing the samples before and after storage at 30 °C for 1 month. Results 1) Sample collection: The material was collected with sampling probes and the collection amounts were 106% (compared to theoretical amount).2) Uniformity: Uniformity of hemoglobin during production was within the specification of “Uniformity of dosage units” section of the pharmacopoeias, acceptance value<15.0. Uniformity of hemoglobin among three vials was within ±10% CV.3) Stability of hemoglobin: Stabilities of the material were all within ±10% from the control material (frozen) after storage at all temperature conditions. Evaporation from the material in a vial was below 1% at 30 °C storage for 1 month. Conclusions This artificial stool is suitable for EQA material because it is confirmed that it shows favorable analytical results in sample collection, uniformity, and stability of hemoglobin. The evaluation of this material in the EQA program to show its suitability was performed by Labquality. The result is reported in a poster at ADLM 2024.

Transition from sulfur autotrophic to mixotrophic denitrification: Performance with different carbon sources, microbial community and artificial neural network modeling

To address the limitations inherent in both sulfur autotrophic denitrification (SAD) and heterotrophic denitrification (HD) processes, this study introduces a novel approach. Three carbon sources (glucose, methanol, and sodium acetate) were fed into the SAD system to facilitate the transition towards mixotrophic denitrification. Batch experiments were conducted to explore the effects of influencing factors (pH, HRT) on the denitrification performance of the mixotrophic system. Carbon source dosages were varied at 12.5%, 25%, and 50% of the theoretical amounts required for HD (18, 36, and 72 mg/L, respectively). The results showed distinct optimal dosages for each of the three organic carbon sources. The mixotrophic system, initiated with sodium acetate at 25% of the theoretical value, demonstrated the highest denitrification performance, achieving NO3−-N removal efficiency of 99.8% and the NRR of 6.25 mg/(L·h). In contrast, the corresponding systems utilizing glucose (at 25% of the theoretical value) and methanol (at 50% of the theoretical value) achieved lower removal efficiency of 77.0% and 88.4%, respectively. The corresponding NRRs were 4.85 mg/(L·h) and 5.65 mg/(L·h). Following the transition from SAD to a mixotrophic system, the abundance of Thiobacillus decreased from 78.5% to 34.4% at the genus level, and the mixotrophic system cultivated a variety of other denitrifying bacteria (Thauera, Aquimonas, Azoarcus, and Pseudomonas), indicating an enhanced microbial community structure diversity. The established artificial neural network (ANN) model accurately predicted the effluent quality of mixotrophic denitrification, which predicted values closely aligning with experimental results (R2 > 0.9). Furthermore, initial pH exerted greater relative importance for COD removal and sulfur conversion, while the relative importance of HRT was more pronounced for NO3−-N removal.

Design Optimization and Experimentation of Triple-Head Gradually Reducing Spiral Precision Fertilizer Apparatus

In order to solve the problems of existing spiral fertilizer apparatuses, such as the variation in cavity filling rate with rotational speed, fluctuation of fertilizer discharge flow, and inability to discharge fertilizer precisely, a triple-head gradually reducing spiral fertilizer apparatus is designed, which gradually compresses fertilizer particles through the triple-head reducing fertilizer spiral structure to achieve complete cavity filling and uniform fertilizer discharge. The main factors that affect the particle motion state and the structural size of the spiral fertilizer through theoretical analysis are determined, and its theoretical fertilizer discharge amount and rotational speed are calculated. Using EDEM (Discrete Element Method Software 2022) to establish a simulation model of a single-head gradually reducing fertilizer apparatus, the spiral lead reduction percentage x1, spiral diameter reduction percentage x2, and rotational speed x3 are determined as experimental factors, and the filling rate μ and spiral torque Yaverage are used as experimental indicators to conduct a simulation study on the secondary universal rotation combination design experiment. The results show that when the rotational speed is 95 r/min, the spiral lead reduction percentage is 60.00~73.21%, the spiral diameter reduction percentage is 86.55~97.05%, the filling rate μ is greater than 95%, and the spiral torque Yaverage is less than 16 N·m. In order to further improve the uniformity of fertilizer discharge and ensure the controllable accuracy of fertilizer discharge, comparative verification experiments are conducted on single-, double-, and triple-head gradually reducing spiral fertilizer discharge devices and ordinary spiral fertilizer discharge devices. The results show that the precision of the gradually reducing spiral fertilizer apparatus is better than that of the ordinary spiral fertilizer apparatus. Moreover, it is determined that the three-head style performed best. The triple-head gradually reducing spiral fertilizer apparatus is also validated by randomly adjusting six rotational speeds. The experiment results show that the average deviation of the fertilizer discharge flow rate of the fertilizer apparatus from the preset value is 3.16%. The two have a minor deviation, and the fertilizer precision is high. Precise control of the amount of fertilizer discharged can be achieved by adjusting the rotational speed, and the research can provide a specific reference for the improved design and precise control of the spiral fertilizer apparatus.

Hollow nickel sources for improving nickel utilization in Zebra batteries

The Zebra (Na-NiCl2) batteries are regarded as a promising option for large-scale electrical energy storage due to their plentiful electrode material resources, high energy density, and safety features. In the cathode of Zebra battery, the nickel powders serve as both an active material and a conductive agent. In practice, its amount is significantly greater than its theoretical usage, often exceeding three times the theoretical amount. Hence, the presence of ultra-excessive nickel results in high material costs, posing obstacles to the wider implementation of Zebra batteries. To address this problem, we introduce hollow nickel source as active material to improve the nickel utilization in Zebra battery. In this work, we assemble Zebra batteries using nickel hollow spheres (NHS) with sizes of ∼200 nm, ∼500 nm, ∼1 μm and ∼ 5 μm as nickel source. The battery using NHSs with a size of 1 μm exhibits the best cycling performance and the lowest polarization voltage. By reducing the Ni(NHS, ∼1 μm)/NaCl mass ratio to 1.0, 60% theoretical capacity can be achieved after 170 cycles at 260 °C, which surpasses the traditional batteries using solid nickel source at the same Ni/NaCl ratio. This performance is comparable to that of traditional solid nickel sources with a mass ratio of 1.5 to NaCl. Therefore, using NHS as the nickel source in Zebra batteries reduces nickel usage by 33% without compromising performance.

Kinetics study on the low-temperature soda roasting of boron-rich blast furnace slag

The method of preparing borax by low-temperature soda roasting and water leaching of boron-rich blast furnace slag (BRBFS) is a novel method for extracting boron from BRBFS. In order to further improve the water leaching rate of boron, this article mainly studied the low-temperature soda roasting kinetics of BRBFS. The effects of roasting temperature and Na2CO3 addition on the water leaching rate of boron were investigated. The results demonstrate that when the amount of Na2CO3 added is four times of the theoretical amount, the kinetics of NaBO2 formation can be described by the Nucleation (Avrami) model in the temperature range of 600–700 °C. The corresponding apparent activation energy is 54.45 kJ/mol, and the apparent frequency factor is 215.16 h−1. It was found that at a roasting temperature of 700 °C,when the amount of sodium carbonate added is twice, three times, and four times of the theoretical amount, the kinetics of NaBO2 formation matches with 3-D Diffusion (Jander) model, Nucleation and Growth (Avrami-Erofeev) model, and Nucleation (Avrami) model, respectively. With an increase in the amount of Na2CO3 added, the rate-controlling step for the formation of NaBO2 transitions from being diffusion-controlled to nucleation-controlled.

Efficient removal of cadmium and lead in water by using nano-manganese oxide-loaded hydrochloric acid pretreated biochar

Cadmium (Cd) and lead (Pb) contaminated water pose a serious threat to the safety of aquatic organisms and human food, which is a hot topic in the world. To improve the removal efficiency of straw biochar (BC) on Cd and Pb pollution water, the modified biochar (BCHMn) was manufactured by loading nano-manganese oxide (nano-MnOx) on hydrochloric acid pretreated BC. The adsorptive properties of Cd2+ and Pb2+ for BCHMn were examined by isothermal, kinetic adsorption models, and cycle tests. The results indicated that the adsorption of Cd2+ and Pb2+ by BCHMn is suitable for Langmuir, Sips, Avrami, and pseudo-second-order kinetic model, suggesting monolayer and heterogeneous chemical adsorption. The maximum theoretical adsorptive amount of Cd2+ and Pb2+ on BCHMn are 108.21 mg/g and 312.16 mg/g, respectively. The adsorption mechanism of BCHMn is primarily mineral precipitation, π electron interaction, and ion exchange. Moreover, BCHMn contained the special birnessite (δ-MnO2) structures and MnOx, which can form stable complexes with Cd/Pb (such as Mn-O-Cd/Pb and Mn-R-O-Cd/Pb). These results indicate that BCHMn can efficiently remove Cd2+ and Pb2+ from water, and provide a reference for the comprehensive utilization of straw waste and water pollution control.

Low-temperature hydrogen release exceeding 7 wt% from LiBH4-mannitol composites

Among conventional hydrogen storage materials, LiBH4 has been regarded as one of the best hydrogen transporters due to its relatively large hydrogen capacities. However, because of its extraordinarily high dehydrogenation temperatures, LiBH4 was not suitable for hydrogen storage due to its stable thermodynamic features. Herein, we present a novel approach to LiBH4 that uses solid-state multi-hydroxyl mannitol as a reactant, regulating hydrogen release below 69.9 °C. More than 7 wt% H2 could be released with ultra-fast rates at 140 °C from the LiBH4-mannitol composite. XRD, FTIR, and SEM tests revealed that the reaction between mannitol (Hδ+) and LiBH4 (Hδ−) to produce hydrogen was accompanied by the generation of large amounts of heat in situ, which further promoted the decomposition of LiBH4 for hydrogen production, exceeding the theoretical dehydrogenation amount of Hδ+- Hδ− reaction. This work indicates possibilities for the development of fast and easy high-capacity hydrogen generation systems based on complex hydrides.

Magnetite addition reduces nitrite requirement for efficient anaerobic ammonium oxidation by facilitating mutualism of ANAMMOX and FEAMMOX bacteria

Partial nitrification (PN) is crucial for anaerobic ammonium oxidation (ANAMMOX), but faces challenges such as high energy demands and process control. Recent research has highlighted additives like magnetite as potential alternatives to conventional electron acceptors (O₂ and NO₂−) for enhancing ammonium (NH4+) oxidation with lower energy consumption. This study investigated the effect of adding 50 mg/L of magnetite to ANAMMOX reactors, resulting in improved nitrogen (N) removal efficiency. The magnetite-added ANAMMOX (M-ANA) reactor yielded N removal efficiencies of 71 %, 66 %, and 57 % for NH4+:NO2− molar ratios of 1:1.3, 1:0.8, and 1:0.5, respectively. The M-ANA reactor operated under a 0.5 mol lower NO2− concentration achieved similar performance to the control ANAMMOX (C-ANA) reactor operated with a theoretical amount of NO2−. Moreover, the M-ANA reactor showed the potential to remove NH4+ by 56 % without any NO2− supplementation. Metagenomic analysis showed that the addition of magnetite significantly improved the relative abundance of microorganisms involved in the FEAMMOX reaction, such as Fimbriimonas ginsengisoli and Pseudomonas stutzeri. It also facilitated positive mutualism between ANAMMOX and FEAMMOX reactions. In addition, M-ANA granules exhibited a dense and compact structure compared with C-ANA, and the presence of magnetite facilitated the formation of resilient granules. Notably, the useful protein (Heme C) concentration and specific microbial activity in the M-ANA reactor were 1.3 and 2.2 times higher than those in the C-ANA reactor. Overall, the results demonstrate that an appropriate amount of magnetite can enhance the N removal efficiency while reducing the energy input requirements and associated carbon emissions. These findings can guide the future development of carbon- and energy-neutral N removal processes.

Standards-Free Absolute Quantitation of Oxidizable Glycopeptides by Coulometric Mass Spectrometry.

Currently, glycopeptide quantitation is mainly based on relative quantitation due to absolute quantitation requiring isotope-labeled or standard glycopeptides which may not be commercially available or are very costly and time consuming to synthesize. To address this grand challenge, coulometric mass spectrometry (CMS), based on the combination of electrochemistry (EC) and mass spectrometry (MS), was utilized to quantify electrochemically active glycopeptides without the need of using standard materials. In this study, we studied tyrosine-containing glycopeptides, NYIVGQPSS(β-GlcNAc)TGNL-OH and NYSVPSS(β-GlcNAc)TGNL-OH, and successfully quantified them directly with CMS with a discrepancy of less than 5% between the CMS measured amount and the theoretical amount. Taking one step further, we applied this approach to quantify glycopeptides generated from the digestion of NIST mAb, a monoclonal antibody reference material. Through HILIC column separation, five N297 glycopeptides resulting from NIST mAb tryptic digestion were successfully separated and quantified by CMS for an absolute amount without the use of any standard materials. This study indicates the potential utility of CMS for quantitative proteomics research.

Durability of Prestressed Piles in a Leachate Environment.

Prestressed pipe piles are common concrete components characterized by dense concrete structures and favorable mechanical properties, and thus, extensively used as coastal soft soil foundations. However, their durability in harsh environments has not been fully clarified. In this study, leachate from an actual landfill site was collected from the east coast of China as the corrosive medium, and the corrosion process was accelerated by electrifying prestressed pipe piles. The results demonstrated that the concentration of chloride ions in the concrete of the prestressed pile increased with the increase in corrosion time. Moreover, the experimental corrosion of these prestressed piles in the drying-wetting cycle proved to be the most severe. However, a protective layer of epoxy resin coating can effectively inhibit the diffusion of chloride ions into the interior of the piles. The final theoretical corrosion amounts of the piles were 1.55 kg, 1.20 kg, and 1.64 kg under immersion, epoxy resin protection, and a drying-wetting cycle environment. The application of epoxy resin reduced chloride penetration by 22.6%, and the drying-wetting cycle increased chloride penetration by 5.8%, respectively, with corresponding corrosion potentials following similar patterns. The actual corrosion depth of the welding seam was 3.20 mm, and there was a large corrosion allowance compared with the requirement (6.53 mm) for the ultimate bending moment. In summary, these prestressed piles exhibited good durability in a leachate environment.

AbInitio Uncertainty Quantification of Neutrinoless Double-Beta Decay in ^{76}Ge.

The observation of neutrinoless double-beta (0νββ) decay would offer proof of lepton number violation, demonstrating that neutrinos are Majorana particles, while also helping us understand why there is more matter than antimatter in the Universe. If the decay is driven by the exchange of the three known light neutrinos, a discovery would, in addition, link the observed decay rate to the neutrino mass scale through a theoretical quantity known as the nuclear matrix element (NME). Accurate values of the NMEs for all nuclei considered for use in 0νββ experiments are therefore crucial for designing and interpreting those experiments. Here, we report the first comprehensive abinitio uncertainty quantification of the 0νββ-decay NME, in the key nucleus ^{76}Ge. Our method employs nuclear strong and weak interactions derived within chiral effective field theory and recently developed many-body emulators. Our result, with a conservative treatment of uncertainty, is an NME of 2.60_{-1.36}^{+1.28}, which, together with the best-existing half-life sensitivity and phase-space factor, sets an upper limit for effective neutrino mass of 187_{-62}^{+205} meV. The result is important for designing next-generation germanium detectors aiming to cover the entire inverted hierarchy region of neutrino masses.

Discursive Strategies in China’s Live Commerce Anchors Multimodality

At present, discourse analysis is widely used in news reports and TV talk shows in China, but there is a lack of discourse analysis research on live streaming. Against this backdrop, this study adopts a multimodal discourse analysis approach, drawing upon the comprehensive theoretical framework for multimodal discourse analysis and Kress and Van Leeuwen's seminal visual grammar theory as the theoretical basis, taking quality and quantity method to analyze data. Our research aims to investigate the intricate interplay between anchors and the amalgamation of diverse modalities in the process of constructing their image. Furthermore, we endeavor to analyze potential strategies that can be employed to enhance the efficacy of live broadcasting and augment viewers' engagement and consumption. In this paper, we decompose the multimodal discourse of the selected live video of “Oriental selection” into verbal and non-verbal modes, and analyze the process and role of how anchors use multimodality to form interactions and promote construction.

Postoperative Opioid Prescribing via Rule-Based Guidelines Derived from In-Hospital Consumption: An Assessment of Efficacy Based on Postdischarge Opioid Use.

Many institutions have developed operation-specific guidelines for opioid prescribing. These guidelines rarely incorporate in-hospital opioid consumption, which is highly correlated with consumption. We compare outcomes of several patient-centered approaches to prescribing that are derived from in-hospital consumption, including several experimental, rule-based prescribing guidelines and our current institutional guideline. We performed a retrospective, cohort study of all adults undergoing surgery at a single-academic medical center. Several rule-based guidelines, derived from in-hospital consumption (quantity of opioids consumed within 24 hours of discharge), were used to specify the theoretical quantity of opioid prescribed on discharge. The efficacy of the experimental guidelines was compared with 3 references: an approximation of our institution's tailored prescribing guideline; prescribing all patients the typical quantity of opioids consumed for patients undergoing the same operation; and a representative rule-based, tiered framework. For each scenario, we calculated the penalized residual sum of squares (reflecting the composite deviation from actual patient consumption, with 15% penalty for overprescribing) and the proportion of opioids consumed relative to prescribed. A total of 1,048 patients met inclusion criteria. Mean (SD) and median (interquartile range [IQR]) quantity of opioids consumed within 24 hours of discharge were 11.2 (26.9) morphine milligram equivalents and 0 (0 to 15) morphine milligram equivalents. Median (IQR) postdischarge consumption was 16 (0 to 150) morphine milligram equivalents. Our institutional guideline and the previously validated rule-based guideline outperform alternate approaches, with median (IQR) differences in prescribed vs consumed opioids of 0 (-60 to 27.25) and 37.5 (-37.5 to 37.5), respectively, corresponding to penalized residual sum of squares of 39,817,602 and 38,336,895, respectively. Rather than relying on fixed quantities for defined operations, rule-based guidelines offer a simple yet effective method for tailoring opioid prescribing to in-hospital consumption.

Buswell’s Equation for Quantifying Biohydrogen

Biohydrogen is widely generated by dark fermentation and two-stage anaerobic digestion. Anaerobic digestion can be chemically represented by the Buswell’s equation, which is based on elemental composition of organic matter. When compared to Buswell’s equation for biomethane, its equation for biohydrogen has been given less attention. In this article, the nature of Buswell’s equation for biohydrogen is introduced by using the H-atom method. The mean oxidation number of organic carbons is employed as a metric for counting theoretical quantity of biohydrogen and parameters of Buswell’s equation for biohydrogen. Based on an empirical formula and mean oxidation number of organic carbons, the general Buswell’s equation for biohydrogen is developed. The mathematical relationships among mean oxidation number of organic carbons, empirical formula, quantity of biohydrogen, theoretical biohydrogen potential, and biohydrogen percent yield are also established. Biowastes and bio-substrates are chosen to demonstrate this notion.

Selective adsorption of Cr(VI) by nitrogen-doped hydrothermal carbon in binary system.

Selective adsorption of heavy metal ions from industrial effluent is important for healthy ecosystem development. However, the selective adsorption of heavy metal pollutants by biochar using lignin as raw material is still a challenge. In this paper, the lignin carbon material (N-BLC) was synthesized by a one-step hydrothermal carbonization method using paper black liquor (BL) as raw material and triethylene diamine (TEDA) as nitrogen source. N-BLC (2:1) showed excellent selectivity for Cr(VI) in the binary system, and the adsorption amounts of Cr(VI) in the binary system were all greater than 150mg/g, but the adsorption amounts of Ca(II), Mg(II), and Zn(II) were only 19.3, 25.5, and 6.3mg/g, respectively. The separation factor (SF) for Cr(VI) adsorption was as high as 120.0. Meanwhile, FTIR, elemental analysis and XPS proved that the surface of N-BLC (2:1) contained many N- and O- containing groups which were favorable for the removal of Cr(VI). The adsorption of N-BLC (2:1) followed the Langmuir model and its maximum theoretical adsorption amount was 618.4mg/g. After 5th recycling, the adsorption amount of Cr(VI) by N-BLC (2:1) decreased about 15%, showing a good regeneration ability. Therefore, N-BLC (2:1) is a highly efficient, selective and reusable Cr(VI) adsorbent with wide application prospects.

A sustainable approach for recovering copper and zinc from copper smelting flue dust: Paving the path for waste reduction

The recovery of metals without generating secondary waste is a critical focus in the management of hazardous copper smelting dust. To tackle the challenges associated with arsenic-containing solid waste and waste acid generated by traditional recycling processes, we propose a two-stage roasting process that prioritizes low-temperature roasting for arsenic removal, followed by high-temperature roasting for desulfurization of sulfates. This work focuses on the high-temperature desulfurization behavior of residue after arsenic removal. The changes in composition during roasting were analyzed using TG-DSC, XRD, and SEM. The results revealed that the reaction temperature and the addition of bituminite are pivotal in the desulfurization process. The optimal roasting conditions were obtained to be a reaction temperature of 700 °C and a roasting duration of 3 h. Subsequently, approximately 98.77% of copper and 97.17% of zinc could be leached under conditions of a leaching temperature of 80 °C, a reaction time of 4 h, a sulfuric acid dosage of 3 times the theoretical amount, and a liquid-to-solid ratio of 10:1. This process mitigates the generation and accumulation of arsenic-containing waste acid during copper electrodeposition in the traditional hydrometallurgical process of copper smelting flue dust. It lays the foundation for clean and efficient recovery and also provides insights for recycling other copper-containing wastes.

The time validity of Philip's two‐term infiltration equation: An elusive theoretical quantity?

AbstractThe two‐term infiltration equation is commonly used to determine the sorptivity, , and product, , of the dimensionless multiple and saturated soil hydraulic conductivity from cumulative vertical infiltration measurements (L) at times (T). This reduced form of the quasi‐analytical power series solution of Richardson's equation of Philip enjoys a solid physical underpinning but at the expense of a limited time validity. Using simulated infiltration data, Jaiswal et al. have shown this time validity to equal about 2.5 cm of cumulative infiltration. The goals of this work are twofold. First, we investigate the extent to which cumulative infiltration measurements larger than 2.5 cm bias the estimates of and . Second, we investigate the impact of epistemic errors on the inferred time validities and parameters. Partial infiltration curves up to 2.5 cm of cumulative vertical infiltration improve substantially the agreement between actual and least squares estimates of and . But this only holds if the data generating infiltration process follows Richardson's equation and experimental conditions satisfy assumptions of soil homogeneity and a uniform initial water content. Otherwise, autocorrelated cumulative infiltration residuals will bias the least squares estimates of and . Our findings reiterate and reinvigorate earlier conclusions of Haverkamp et al. and show that epistemic errors deteriorate the physical significance of the coefficients of infiltration functions. As a result, the parameters of infiltration functions cannot simply be used in storm water and vadose zone flow models to forecast runoff and recharge at field and landscape scales unless these predictions are accompanied by realistic uncertainty bounds. We conclude that the time validity of Philip's two‐term equation is an elusive theoretical quantity with arbitrary physical meaning.

Minimum work associated with separating nitrogen from air: An exergy analysis

Background Nitrogen is essential for a variety of industries, including heat treatment, laser cutting, fire protection, and food packaging. Many companies in these industries obtain nitrogen via on-premises air separation processes. The three main processes for separating nitrogen from ambient air are cryogenic distillation, membrane separation, and pressure-swing adsorption (PSA). Improvements to these processes will likely focus on increasing efficiency, resulting in reduced environmental impact owing to less electrical power demand and opportunities for economic incentives. Regardless of the process utilized, a minimum theoretical amount of work input is required to obtain nitrogen gas at different pressures and concentrations compared to ambient conditions. Methods An equation was derived to evaluate the total exergy (including thermo-mechanical and chemical exergy) of product and exhaust mixtures resulting from air separation, indicating the minimum theoretical work input as a function of the product pressure, purity, and process recovery rate. This analysis considered an air separation system as a black box, with the input, output, and exhaust assumed to be ideal gas mixtures of nitrogen and oxygen at 15°C. The analysis applies to cryogenic distillation if the product and exhaust mixtures return to the gas phase. Results In general, the minimum required work input increases with product purity and recovery rate. Plots of minimum theoretical work versus product purity and recovery rate were made for two product pressures (atmospheric and 800 kPa) to show the behavior of the derived equation. Conclusions The analysis allows for direct efficiency (based on the second law of thermodynamics) comparisons between existing processes and future technological innovations in the field of air separation. Actual air separation systems have low efficiencies compared to ideal systems; actual PSA systems were estimated to have second law efficiencies of 5.5–11.2%. Therefore, there is great potential for improvements to current air separation systems.