The investigation into the adsorption removal of ammonium by natural and modified zeolites: Kinetics, isotherms, and thermodynamics

The objectives of this study were to modify Chinese natural zeolite by NaCl and to investigate its suitability as a low-cost clay adsorbent to remove ammonium from aqueous solution. The effect of pH on ammonium removal was investigated by batch experiments. The findings indicated that pH has a significant effect on the removal of ammonium by M-Zeo and maximum adsorption occured at pH 8. Ion exchange dominated the ammonium adsorption process at neutral pH, with the order of exchange selectivity being Na+ > Ca2+ > K+ > Mg2+. The Freundlich model provided a better description of the adsorption process than the Langmuir model. The maximum ammonium adsorption capacity was 17.83 mg/g for M-Zeo at 293K. Considering the adsorption isotherms and thermodynamic studies, the adsorption of ammonium by M-Zeo was endothermic and spontaneous chemisorption. Kinetic studies indicated that the adsorption of ammonium onto M-Zeo is well fitted by the pseudo-second-order kinetic model. Ea in the Arrhenius equation suggested the adsorption of ammonium on M-Zeo was a fast and diffusion-controlled process. The regeneration rate was 90.61% after 5 cycles. The removal of ammonium from real wastewater was carried out, and the removal efficiency was up to 99.13%. Thus, due to its cost-effectiveness and high adsorption capacity, M-Zeo has potential for use in ammonium removal from aqueous solutions.Keywords: zeolite, sodium chloride modified, adsorbent, regeneration, wastewate

Tomographic reconstruction of the Earth’s magnetosheath from multiple spacecraft: a theoretical study

Following our earlier work on tomographic reconstruction of the magnetosheath soft X-ray emissions with superposed epoch analysis of many images recorded from a single spacecraft we now explore the instantaneous reconstruction of the magnetosheath and magnetopause using a few images recorded simultaneously from a few spacecraft. This workis motivated by the prospect of possibly having two or three soft X-ray imagers in spacein the coming years, and that many phenomena which occur at the magnetopause boundary, such as reconnection events and pressure pulse responses, do not lend themselvesas well to superposed epoch analysis. If the reconstruction is successful — which we demonstrate in this paper that it can be — this collection of imagers can be used to reconstructthe magnetosheath and magnetopause from a single image from each spacecraft, allowing for high time resolution reconstructions. In this paper we explore the reconstruction using, two, three, and four spacecraft. We show that the location of the subsolar pointof the magnetopause can be determined with just two satellites, and that volume emissions of soft X-rays, and the shape of the boundary, can be reconstructed using three or more satellites

Global hybrid simulations of soft X-ray emissions in the Earth’s magnetosheath

Earth’s magnetopause is a thin boundary separating the shocked solar wind plasma from the magnetospheric plasmas, and it is also the boundary of the solar wind energy transport to the magnetosphere. Soft X-ray imaging allows investigation of the large-scale magnetopause by providing a two-dimensional (2-D) global view from a satellite. By performing 3-D global hybrid-particle-in-cell (hybrid-PIC) simulations, we obtain soft X-ray images of Earth’s magnetopause under different solar wind conditions, such as different plasma densities and directions of the southward interplanetary magnetic field. In all cases, magnetic reconnection occurs at low latitude magnetopause. The soft X-ray images observed by a hypothetical satellite are shown, with all of the following identified: the boundary of the magnetopause, the cusps, and the magnetosheath. Local X-ray emissivity in the magnetosheath is characterized by large amplitude fluctuations (up to 160%); however, the maximum line-of-sight-integrated X-ray intensity matches the tangent directions of the magnetopause well, indicating that these fluctuations have limited impact on identifying the magnetopause boundary in the X-ray images. Moreover, the magnetopause boundary can be identified using multiple viewing geometries. We also find that solar wind conditions have little effect on the magnetopause identification. The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) mission will provide X-ray images of the magnetopause for the first time, and our global hybrid-PIC simulation results can help better understand the 2-D X-ray images of the magnetopause from a 3-D perspective, with particle kinetic effects considered

Reciprocal and Symbiotic: Family Farms’ Operational Performance and Long-Term Cooperation of Entities in the Agricultural Industrial Chain—From the Evidence of Xinjiang in China

The family farm is an important entity in the modern agricultural industrial chain. It is of great significance to empirically study its operational performance improvement and sustainable development. This paper introduces symbiosis theory to establish a symbiosis system framework of the family farm industrial chain and analyzes family farms’ operational performance from the view of industrial symbiosis cooperation. We selected 552 agricultural planting family farms in China’s Xinjiang Production and Construction Corps as samples to measure the operational environment and performance of family farms using factor analysis and examining the effects of long-term cooperation among the industrial chain entities on family farms’ operational performance using the ordered probit model. The results show that the long-term cooperation of the family farms with other entities has a significant positive impact on the family farms’ operational performance, which can be enhanced by the improvement of cooperation and moderated by the external environment. Therefore, it is suggested to promote the long-term cooperation between family farms and other industrial chain entities, as well as the industrial environment optimization, to accelerate the healthy and sustainable development of family farms with a continuous, symmetrical, and reciprocal symbiotic model

Prognostic value of liver stiffness measurement for the liver-related surgical outcomes of patients under hepatic resection: A meta-analysis.

Previous studies have discussed the liver stiffness measurement (LSM) performance on predicting liver-related surgical outcomes for patients of hepatocellular carcinoma (HCC) under hepatic resection, yet there is much variation in reporting and consistency of findings. Therefore, we report a meta-analysis on this issue.We comprehensively searched PubMed, Embase, and Web of science to find the eligible cohort studies. The pooled Odds Ratios (OR) and 95% confidence intervals (CIs) were calculated to evaluate effect. The weighted mean LSM value was calculated as the optimal LSM cut-off value among studies.12 prospective cohort studies and one retrospective cohort study, including a total of 1942 cases were identified. The pooled results showed that preoperative LSM is significantly associated with the occurrence of overall postoperative complications (OR 1.76, 95% CI 1.46-2.11). In addition, a weighted mean LSM value of 14.2 kPa and 11.3KPa were suggested as the optimal LSM cut-off value reference using transient elastoqraphy (TE) for predicting overall postoperative complications in Asia countries and European countries, respectively.Preoperative LSM should be taken into account cautiously in the management of patients undergoing hepatectomy of HCC. Future studies could focus on setting a prognostic model integrated with LSM in predicting post-hepatectomy outcomes

The generation and application of antioxidant peptides derived from meat protein: a review

Meat and its products, rich in protein, are one of the important potential sources of antioxidant peptides. However, reviews on the generation and application of meat-derived antioxidant peptides are still limited. To understand the research and application progress of meat-derived antioxidant peptides, the main formation pathways and their commercial applications are exhibited, the research methods for the isolation, purification, and identification are summarized, and the influencing factors, evaluation methods, and intestinal absorption pathways are presented in this work. It is summarized that limited degradation by exogenous and endogenous enzymatic hydrolysis is the main pathway for the production of animal-derived antioxidant peptides. Traditional separation, purification, and identification techniques are also applicable to animal-derived antioxidant peptides. The formation of animal-derived antioxidant peptides is affected by many factors, and the intestinal absorption pathways of antioxidant peptides are different. Finally, insufficient and future development directions are provided

Forest plot meta-analyses of studies evaluating the sensitivity of live stiffness measured by TE to predict the overall postoperative complications.

<p>Forest plot meta-analyses of studies evaluating the sensitivity of live stiffness measured by TE to predict the overall postoperative complications.</p

Polydopamine-Functionalized Copper Peroxide/ZIF-8 Nanoparticle-Based Fluorescence-Linked Immunosorbent Assay for the Sensitive Determination of Carcinoembryonic Antigen by Self-Supplied H₂O₂ Generation

Copper peroxide/zeolitic imidazolate framework/polydopamine nanoparticles (CP/ZIF-8/PDA)-based fluorescence-linked immunosorbent assay (FLISA) was designed for the sensitive and high-throughput determination of carcinoembryonic antigen (CEA) by self-supplied H2O2 generation. Specifically, the CEA aptamer was modified on the surface of CP/ZIF-8/PDA to form an immunoprobe. The structures of CP and ZIF-8 could be broken under acidic conditions, and produced the Cu2+ and H2O2 due to the dissociation the CP. A subsequent Fenton-type reaction of Cu2+ and H2O2 generated hydroxyl radical (·OH). o-phenylenediamine (OPD) was oxidized by the ·OH to form 2, 3-diaminophenazine (DPA) with a significant fluorescence signal. CP/ZIF-8/PDA could be used as an efficient Fenton-type reactant to generate a large amount of ·OH to promote OPD oxidation. The sensitive detection of CEA could be realized. Under optimal conditions, the FLISA platform displayed a linear detection range from 0.01 to 20 ng mL−1 with a detection limit of 7.6 pg mL−1 for CEA. This strategy has great application potential for sensitive and high-throughput determination for other biomarkers in the field of biomedicine