Coexistence System Research Articles

The effect of nano-Fe3O4 addition on the nitrogen transfer pathways and biomass morphology in floc-granule coexistence system

The effect of nano-Fe3O4 addition on the nitrogen transfer pathways and biomass morphology in floc-granule coexistence system

Green synthesis of starch/chitosan complex via ozone-mediated Schiff reaction: Structure, thermal behaviors and surface properties

Ozone was used as a green and environmentally friendly initiator to directly induce a Schiff base cross-linking reaction between chitosan and waxy rice starch (CS) in the present investigation. The effects of oxidation on the structure of chitosan/starch bio-based composite, along with the cross-linked structure formation via Schiff base reaction, were investigated and confirmed using FTIR, XRD, and XPS characterization techniques. The formation of new bonds (C=N) along with other attributes imparted by the cross-linking reaction were evaluated and characterized. Notably, the ozone-induced cross-linking reaction significantly altered the water retention capabilities of CS, especially in the case of aqueous ozone treatment, which significantly improved its swelling power, water holding capacities, and water adsorption. Additionally, aqueous ozone treatment facilitated the formation and stabilization of the gel network. Gaseous ozone in dry state proved more effective in promoting the formation of CN groups, leading to enhanced surface hydrophobicity, while aqueous ozone offered better oxidation uniformity for the coexistence system of chitosan and starch. This work provides a novel and environmentally friendly approach for fabricating the chitosan/starch chemically cross-linking materials through ozone-induced direct Schiff base reaction, which simplifies the preparation process of the complex and minimizing the utilization of solvents.

New insights into rice starch-gallic acid-whey protein isolate interactions: Effects of multiscale structural evolution and enzyme activity on starch digestibility

In starch-based food where proteins and polyphenols coexist, the impact of protein on the inhibition of starch digestion by polyphenols is unclear. Therefore, the aim of this study was to investigate the impact of whey protein isolate (WPI) on the inhibition of rice starch digestion by gallic acid (GA) from the aspects of multiscale structure and enzyme activity. Rice starch-gallic acid-whey protein isolate complex (RS-GA-WPI) was formed predominantly by hydrogen bonding and hydrophobic interactions. Compared to rice starch-gallic acid complex (RS-GA), RS-GA-WPI exhibited higher short-range ordering and thermal stability, and lower relative crystallinity. Fluorescence spectra and molecular docking showed that the interactions between GA and WPI weakened the hydrogen bond between GA and enzyme active site, so that WPI significantly reduced the enzyme inhibitory activity of GA. The above factors led to the result that the presence of WPI weakened the inhibitory effect of GA on starch digestibility. RS-GA-WPI showed higher starch digestibility and lower resistant starch content compared to RS-GA. This study provided a new understanding of starch digestion mechanism in starch-polyphenol-protein coexistence system.

Co-existing sanitation systems in dense urban areas

Co-existing sanitation systems in dense urban areas

Eu-doped carbon dots-MOF based turn-on fluorescent probe for trace Hg2+ and Pb2+ and construction of the simultaneous detection model

Multiple trace heavy metal pollutants present a serious threat to the aquatic environment, and their coexistence also affected the detection efficiency. This work prepared Eu doped metal organic framework (MOF) complexed with S-containing carbon dots (CD(s)) exhibited dual-emission fluorescence. Its chelation-enhanced fluorescence with heavy metals replaced the original agglomerative fluorescence quenching of pure CD(s), which was utilized to construct a “turn on” fluorescence sensing probe. Based on the XPS, DFT and fluorescence lifetime results, the N, S functional groups on the surface of the materials could bind specifically to Hg2+ and Pb2+ with enhanced sensitivity. The limit of detection reached 76.67 nM for Hg2+ and 5.12 nM for Pb2+ within 2 min detection time. Furthermore, due to the different response mechanism of the two signal peaks to Hg2+ and Pb2+, a three-dimensional data model was developed for simultaneous detection in the co-existence system. The model had been successfully applied to actual Hg2+-Pb2+ containing water samples with recoveries ranged from 93.15 ∼ 105.08 %. The results provided a new strategy for simultaneous detection of trace environmental pollutants.

A joint resource allocation strategy in a radar-communication coexistence network for target tracking and user serving

With the rapid development of commercial communications, the research on Radar-Communication Coexistence (RCC) systems is becoming a hot spot. The resource allocation techniques play a crucial role in the RCC systems. A performance-driven Joint Radar-target and Communication-user Assignment, along with Power and Subchannel Allocation (JRCAPSA) strategy, is proposed for an RCC network. The optimization model aims to minimize the sum of weighted Bayesian Cramér-Rao Lower Bounds (BCRLBs) of target state estimates for radar purpose. This is subject to constraints such as the Communication Data Rate (CDR) for communication purpose, the total power budget in each RCC system, assignment relationships, and the number of available subchannels. Considering that such a problem falls into the realm of Mixed Integer Programming (MIP), a Three-stage Iteratively Augment-based Optimization Method (TIAOM) is developed. The Communication-User Assignment (CUA), Communication Subchannel Allocation (SCA), and Radar-Target Assignment (RTA) feasible solution domains are iteratively expanded based on their importance, leading to the efficient acquisition of a suboptimal solution. Simulation results show the outperformance of the proposed JRCAPSA strategy, compared to the other benchmarks and the OPTI toolbox. The results also imply that the Bayesian Cramér-Rao Lower Bound (BCRLB) is a more stringent optimization metric for the achieved Mean Square Error (MSE), compared to Mutual Information (MI) and Signal-to-Interference-Noise Ratio (SINR).

Heat-Induced Liquid Hovering in Liquid-Gas Coexistence under Gravity.

We study a liquid-gas coexistence system in a container under gravity with heat flow in the direction opposite to gravity. By molecular dynamics simulation, we find that the liquid buoys up and continues to float steadily. The height at which the liquid floats is determined by a dimensionless parameter related to the ratio of the temperature gradient to gravity. We confirm that supercooled gas remains stable above the liquid. We provide a phenomenological argument for explaining the phenomenon from a simple thermodynamic assumption.

Molecular dynamics simulations of the effect of static electric field on progressive ice formation.

Ice accumulation under static electric fields presents a significant hazard to transmission lines and power grids. Contemporary computational studies of electrofreezing predominantly probed excessive electric fields (109 V/m) that are significantly higher than those typically encountered in proximity to transmission lines. To elucidate the influence of realistic electric fields (105 V/m) on ice crystallization, we run extensive molecular dynamics (MD) simulations across dual ice-water coexistence systems. Three aspects of work were accordingly examined. First, we investigated the influence of the effect of static electric fields, with a strength of 105 V/m, along three orthogonal axes on the phase transition during the encountered freezing and melting processes. Second, we established the mechanism of how the direction of an electric field, the initial ice crystallography, and the adjacent crystal planes influence the solidification process. Third, the results of our MD simulations were further post-processed to determine the dipole moment, radial distribution, and angle distribution resulting from the static electric field. Our results indicate that while weak electric fields do not cause complete polarization of liquid water molecules, they can induce a transition to a more structured ice-like geometry of the water molecules at the ice-water interphase region, particularly when applied perpendicular to the ice-water interphase. Notably, the interface adjacent to cubic ice exhibits a greater response to the electric fields than that adjacent to hexagonal ice. This is attributable to the intrinsic differences in their original hydrogen bonding networks.

Study on the Destruction Law and Main Controlling Factors of Corrosion Product Film in H2S-CO2 Coexistence System

Abstract The failure law and main controlling factors of corrosion product film in this corrosion environment were studied according to the characteristics of H2S-CO2 coexistence in a gas field pipeline, so as to provide guidance for corrosion prevention and control of gas field pipeline. Sediment effects of sand particles in the pipeline on corrosion, the influence of flow rate, dissolved oxygen and sediment on corrosion products were analyzed by conducting corrosion experiments at 0.5m/s, 1m/s and 2m/s, corrosion experiments without oxygen and aerobic conditions. The destruction law of corrosion product film in pipeline and the main controlling factors of corrosion product film in single well pipeline and gathering and transportation line were determined. The results show that high flow rate will cause local damage of corrosion product film and promote pitting corrosion, dissolved oxygen will destroy the integrity of corrosion product film, and sediment is one of the factors causing local corrosion and perforation of pipeline inner wall. The corrosion product film structure of the gas field pipeline will be destroyed and pitting corrosion under the condition of high flow rate, oxygen and sand deposition. Meanwhile, the main control factor affecting the corrosion product film destruction of the gas field single well pipeline is dissolved oxygen, and the main control factor affecting the corrosion product film destruction of the gas field gathering and transportation main line is sediment.

Molecular Dynamics Simulation Investigation of Freezing Point Depression in NaClO4 Electrolyte Solution by CaCl2.

The development of inorganic antifreeze electrolytes is of paramount importance for the application of sodium-ion batteries under low-temperature conditions. However, there is little reported about their molecular mechanism for lowering the freezing point of electrolytes. Therefore, this study explores the mechanism by which CaCl2 lowers the freezing point of the NaClO4 electrolyte. Hexagonal ice (ice Ih) was used as the ice seed, and CaCl2 was selected as the antifreeze agent. The coexistence system of ice and solution was constructed to simulate the freezing process. It was found that there is ion rejection at the ice layer, with ions predominantly distributed in the solution. Over time, ions form an ion adsorption layer at the ice-solution interface. The radial distribution function (RDF) and spatial distribution function (SDF) of Na+, ClO4-, Ca2+, and Cl- revealed that ions form the first solvation shells with water molecules. The interaction energy between ions and water molecules is greater than that between ice nuclei and water. Therefore, ions are better able to maintain the stability of their solvation shells and inhibit the growth of ice Ih through a mechanism of competition for water molecules. Furthermore, the dissolution free energy of Na+ and Ca2+ in the aqueous phase was studied. The results indicated that Ca2+ has a stronger affinity for water molecules than Na+, making it more competitive in competing for water with ice Ih. Therefore, CaCl2 in NaClO4 solution can reduce the freezing point. This work provides a molecular-level understanding of how CaCl2 reduces the freezing point of NaClO4 solution, which is beneficial for designing strategies for low-temperature electrolytes.

A facile acid-etching defect-rich leaf-like zeolitic-imidazolate framework adsorbent for simultaneous removal of organic/inorganic phosphorus pollutants from wastewater

Organophosphorus herbicide glyphosate and inorganic phosphate usually coexist in wastewater, leading to water eutrophication and posing risks to human health. In this study, acid-etching defect-rich leaf-like zeolitic-imidazolate framework (ae-ZIF-L) adsorbent was developed by a facile etching method to investigate its simultaneous removal performance of glyphosate and phosphate. Compared to ZIF-L precursor, ae-ZIF-L displayed a maximum adsorption capacity for phosphate and glyphosate of 164.4 mg g–1 and 12.7 mg g–1, respectively. The overall enhanced adsorption performance of ae-ZIF-L was primarily attributed to abundant Zn defects, resulting in higher positive zeta potentials to enhance electrostatic attraction. Notably, in the phosphate/glyphosate coexistence system, ae-ZIF-L has extremely high removal rates of 99.1 % and 90.9 %, while ZIF-L has removal rates of 97.7 % and 39.4 %, respectively. Furthermore, after four adsorption-desorption cycles, the removal rates of phosphate/glyphosate by ae-ZIF-L remained at 84.8 % and 82.5 %, respectively. In conclusion, ae-ZIF-L proved to be an efficient and reusable adsorbent with promising application for the treatment of organic/inorganic phosphorus pollution in wastewater.

Effect of two-dam coexistence on thermal regime: A special withdrawal measure in Fengman reservoir, China

The Fengman Reservoir in China employs a distinctive approach termed two-dam coexistence to mitigate the risks associated with aging and hazardous dams. This method involves the partial demolition of the old dam and construction of a new dam downstream, which allows the remaining part of the old dam to act as a retaining wall for selective water withdrawal. Through a comprehensive study, long-term water temperature data were analyzed, along with the characteristics of the two-dam coexistence system, to comprehend its effects on thermal stratification in the main basin near the dams and the withdrawal water temperature (WWT) regime. The results revealed that the metalimnion shifted upwards, strengthening stratification, and the temperature gradient expanded from 0–0.9 °C/m to 0–10.5 °C/m compared to that under the one-dam condition. Vertical mixing was reduced, causing the temperature difference between surface and bottom waters to range from 6.8 to 26.8 °C. This enhanced the stratification stability by 1.8 times compared with the one-dam condition, with some annual variability. Thus, the buoyancy frequency decreased accordingly. Furthermore, two-dam coexistence influenced the WWT, resulting in higher WWT during the warming period (averaging 4.3 °C from May to June) and lower WWT during the freeze-up period (averaging 0.1 °C from January to February) than that of the one-dam condition. The most significant temperature difference between the main basin near the old dam and the one near the new dam occurred at the bottom of the reservoir (ranging from 3.5 to 12.0 °C), confirming that the old dam functioned as a retaining wall, allowing the thermal regime to change. Owing to the two-dam coexistence, the withdrawal layer shifted by 20.0 m from near the intake to close to the demolition elevation. These changes in stable stratification and variations in WWT play crucial roles in reservoir management. This study offers practical insights for treating similar aging and hazardous reservoirs and serves as a reference for optimizing water quality management strategies.

The influence of carbonate on the adsorption performance and mechanism of LDHs toward Cd and As

The excellent adsorption performance of layered double hydroxides (LDHs) toward heavy metals (HMs) had been demonstrated. The carbonate contamination was one of the inherent problems for LDHs whether during the synthesis or application procedure, which significantly affected the adsorption performance of LDHs toward HMs. However, a few studies investigated the mutual effect and mechanism between HMs on LDHs with carbonate interference, especially for the coexistence system of cationic and anionic HMs. In this study, cadmium (Cd) and arsenate (As) were selected as typical cationic and anionic HMs to study the influences of carbonates on their adsorption performance on LDHs. The carbonate intercalated LDHs (CLDH) promoted Cd adsorption but inhibited As adsorption in single system. The adsorption capacity of Cd increased by ∼ 50 % while As adsorption decreased by half. CdCO3 precipitation contributed to ∼ 40 % of the adsorbed Cd whereas weaker electrostatic adsorption inhibited As adsorption due to lower surface zeta potentials of CLDH than LDH. In contrast, both adsorption capacities and rates of Cd and As on CLDH were promoted in binary system (the co-existence of Cd and As) compared with single system. The surface potentials of CLDH turned from positive to negative with As rapid occupation, facilitating Cd entrance into the interlayers. And then the opening of the interlayer space and rearrangement of CLDH enhanced CdCO3 precipitation and isomorphic substitution. With the increase of surface zeta potentials and rearrangement of CLDH, in turn, the adsorption of As was promoted via electrostatic adsorption (∼65 %) and surface complexation (∼35 %). The adsorption capacity of Cd increased by ∼ 15 % whereas As adsorption decreased by half with increasing pH from 4 to 9 in binary system. In contrast, temperature (15–35 ℃) had negligible influence on the adsorption of CLDH toward Cd and As. Herein, this study illustrated the influence mechanism of carbonate intercalation on the simultaneous immobilization of Cd and As on LDHs, providing an understanding for fates of Cd and As with LDHs in more realistic scenes.

Synergistic and antagonistic adsorption mechanisms of copper(II) and cefazolin onto bio-based chitosan/humic composite: A combined experimental and theoretical study

In this study, a bio-based chitosan adsorbent modified by humic was synthesized. The adsorbent exhibited amphoteric adsorption properties and had a higher adsorption capacity for Cu(II) and cefazolin (CEF) than its precursors. The impacts of pH on the speciation and adsorption of Cu(II) and CEF were analyzed. The synergistic and antagonistic adsorption in Cu(II)/CEF co-existing system were systematically investigated. The adsorption amount of CEF significantly increased by 84 %, owing to the bridge effect of Cu(II). While the uptake of Cu(II) decreased by 29 % at CEF concentration of 0.3 mmol/L, due to the formation of organic ligand complex between Cu(II) and CEF with low affinity to the adsorbent. The adsorption mechanisms of Cu(II) and CEF were analyzed by XPS and Density functional theory (DFT). Through DFT calculations, the interaction configurations of Cu(II) and CEF on adsorbent as well as Cu(II)-CEF complexes were configurated. The possible Cu(II)-CEF complexes configuration were optimized, and the complex configuration (Cu-N2/O1/O2) was the most stable combination structure with the lowest binding energy (−2066.61 kJ/mol). Interaction region indicator (IRI) model further elucidated the chemical and weak interactions between CEF and Cu(II) in coexisting system. In addition, the influence of common inorganic electrolytes on the adsorption of Cu(II) and CEF was assessed. The adsorbent could be stably recycled for five cycles with little loss, indicating the potential application in the treatment of combined pollution. This study proposed more insights into the interactions of heavy metal ions and antibiotics in the coexistence system onto the adsorbents containing amine and carboxyl groups.

Anaerobic cyanides oxidation with bimetallic modulation of biological toxicity and activity for nitrite reduction

Cyanide is a typical toxic reducing agent prevailing in wastewater with a well-defined chemical mechanism, whereas its exploitation as an electron donor by microorganisms is currently understudied. Given that conventional denitrification requires additional electron donors, the cyanide and nitrogen can be eliminated simultaneously if the reducing HCN/CN− and its complexes are used as inorganic electron donors. Hence, this paper proposes anaerobic cyanides oxidation for nitrite reduction, whereby the biological toxicity and activity of cyanides are modulated by bimetallics. Performance tests illustrated that low toxicity equivalents of iron-copper composite cyanides provided higher denitrification loads with the release of cyanide ions and electrons from the complex structure by the bimetal. Both isotopic labeling and Density Functional Theory (DFT) demonstrated that CN−-N supplied electrons for nitrite reduction. The superposition of chemical processes reduces the biotoxicity and enhances the biological activity of cyanides in the CN−/Fe3+/Cu2+/NO2– coexistence system, including complex detoxification of CN− by Fe3+, CN− release by Cu2+ from [Fe(CN)6]3−, and NO release by nitrite substitution of −CN groups. Cyanide is the smallest structural unit of C/N-containing compounds and serves as a probe to extend the electron-donating principle of anaerobic cyanides oxidation to more electron-donor microbial utilization.

The Problem of Conservation of Ethnopedagogical Traditions in the History of China

The importance of the research is that the problem of preserving national identity within a multi-ethnic state, such as China. The ideology of the united Chinese nation is a developed and constantly improved system of coexistence of several ethnic groups within the framework of one state. The purpose of the study is to analyze the formation of ethnopedagogical traditions in the modern education system of China. The modern national policy of China focuses not only on the restoration and preservation of the national identity of each of the peoples as the cultural heritage of the whole country, but also on the coexistence of all peoples in the concept of a single Chinese nation. The idea of harmonious coexistence can be traced throughout Chinese history, which has historically been seen as an economic and social problem. At present, education has become one of the most important aspects of the national policy of the PRC, not only as a mechanism for educating the citizens of the republic, united by a single idea, but also the ability to preserve the culture of each national minority within one country. Research methodology and methods. The basis of the research is done by using such methods as Historical and theoretical analisis and also the method of content analisis of scientific and academic sources. The results of the study can be used in the field of cultural linguistics and social sciences and also as a basis for further study and analysis of the features of the historical stages of the formation of sinology in Russia. The purpose of the article is to identify and substantiate the role of active teaching methods in the development of reading competencies of students in the field of study “Journalism”.

High-performance electrosorption of lanthanum ion by Mn3O4-loaded phosphorus-doped porous carbon electrodes via capacitive deionization

Transition-metal-oxide@heteroatom doped porous carbon composites have attracted considerable research interest because of their large theoretical adsorption capacity, excellent electrical conductivity and well-developed pore structure. Herein, Mn3O4-loaded phosphorus-doped porous carbon composites (Mn3O4@PC-900) were designed and fabricated for the electrosorption of La3+ in aqueous solutions. Due to the synergistic effect between Mn3O4 and PC-900, and the active sites provided by Mn–O–Mn, C/PO, C–P–O and Mn–OH, Mn3O4@PC-900 exhibits high electrosorption performance. The electrosorption value of Mn3O4@PC-900 was 45.34% higher than that of PC-900, reaching 93.02 mg g−1. Moreover, the adsorption selectivity reached 87.93% and 89.27% in La3+/Ca2+ and La3+/Na+ coexistence system, respectively. After 15 adsorption-desorption cycles, its adsorption capacity and retention rate were 50.34 mg g−1 and 54.12%, respectively. The electrosorption process is that La3+ first accesses the pores of Mn3O4@PC-900 to generate an electric double layer (EDL), and then undergoes further Faradaic reaction with Mn3O4 and phosphorus-containing functional groups through intercalation, surface adsorption and complexation. This work is hoped to offer a new idea for exploring transition-metal-oxide @ heteroatom doped porous carbon composites for separation and recovery of rare earth elements (REEs) by capacitive deionization.

Exploring Humic Acid as an Efficient and Selective Adsorbent for Lead Removal in Multi-Metal Coexistence Systems: A Review

Water pollution poses a global threat to human health, particularly in terms of ensuring a safe supply of drinking water. The accumulation of heavy metals from various water sources is increasing, driving the search for effective and environmentally friendly approaches and materials for metal removal. This review investigates the selective adsorption of Pb2+ by humic acid (HA) in a multi-metal coexistence solution. The focus is on discussing approaches to the structural identification of HA, highlighting that separation techniques are an effective method to reduce its heterogeneity. Starting from the key structural units of HA, the study reveals the interaction between HA and heavy metals. Approaches to enhance Pb2+ selective adsorption are explored, proposing that introducing activating groups, Ca ion exchange, and optimizing pore structures are effective approaches for improving lead ion selective adsorption. Ca2+ activation is suggested as a future research direction for lead-selective adsorption. Additionally, attaining lead selective adsorption through pH regulation’s significance is emphasized. This research contributes to a fundamental understanding of HA’s role as a selective lead adsorbent while offering practical implications for developing environmentally friendly adsorbent materials. The results aim to advance knowledge in environmental science and water treatment.

Practical Law Regulatory Thoughts on Cross-Domain Trademark Rights Conflict on the Internet

Based on the characteristics of the Internet and the rapid development of Internet trade, the use of Internet trademarks has aggravated the conflict of cross-domain trademark rights, and the adoption of the trademark coexistence system to solve the conflict of cross-domain trademark rights is appropriate, through the expansion of the explanation of the extension of trademark coexistence system, and the requirement of Internet trademark users to take corresponding technical measures, and the comprehensive generalization of the system of coexistence for the use of trademark, which reflects the value of the expansion of the system of coexistence of trademarks in order to regulate Internet trademark conflicts, and the value of substantive law regulation. This is to realize the value of expanding the trademark coexistence system to regulate cross-domain trademark conflicts on the Internet.

Multifunctional self-assembled adsorption microspheres based on waste bamboo shoot shells for multi-pollutant water purification

In this study, multilayer self-assembled multifunctional bamboo shoot shell biochar microspheres (BSSBM) were prepared, in which bamboo shoot shell biochar was used as the carrier, titanium dioxide as the intermediate medium, and chitosan as the adhesion layer. The adsorption behavior of BSSBM on heavy metals Ag(I) and Pd(II), antibiotics, and dye wastewater was systematically analyzed. BSSBM shows a wide range of adsorption capacity. BSSBM is a promising candidate for the purification of real polluted water, not only for metal ions, but also for Tetracycline (TC) and Methylene Blue (MB). The maximum adsorption amounts of BSSBM on Pd(II), Ag(I), TC and MB were 417.3 mg/g, 222.5 mg/g, 97.2 mg/g and 42.9 mg/g, respectively.The adsorption of BSSBM on Pd(II), MB and TC conformed to the quasi-first kinetic model, and the adsorption on Ag(I) conformed to the quasi-second kinetic model. BSSBM showed remarkable selective adsorption capacity for Ag(I) and Pd(II) in a multi-ion coexistence system. BSSBM not only realized the high value-added utilization of waste, but also had the advantages of low cost, renewable and selective adsorption. BSSBM demonstrated its potential as a new generation of multifunctional adsorbent, contributing to the recovery of rare/precious metals and the treatment of multi-polluted water.