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Comparison of the removal of monovalent and divalent cations in the microbial desalination cell

Shanshan CHEN,Haiping LUO,Yanping HOU,Guangli LIU,Renduo ZHANG,Bangyu QIN

《环境科学与工程前沿(英文)》 2015年 第9卷 第2期   页码 317-323 doi: 10.1007/s11783-013-0596-y

摘要: Microbial desalination cell (MDC) is a promising technology to desalinate water and generate electrical power simultaneously. The objectives of this study were to investigate the desalination performance of monovalent and divalent cations in the MDC, and discuss the effect of ion characteristics, ion concentrations, and electrical characteristics. Mixed salt solutions of NaCl, MgCl , KCl, and CaCl with the same concentration were used in the desalination chamber to study removal of cations. Results showed that in the mixed salt solutions, the electrodialysis desalination rates of cations were: Ca >Mg >Na >K . Higher ionic charges and smaller hydrated ionic radii resulted in higher desalination rates of the cations, in which the ionic charge was more important than the hydrated ionic radius. Mixed solutions of NaCl and MgCl with different concentrations were used in the desalination chamber to study the effect of ion concentrations. Results showed that when ion concentrations of Na were one-fifth to five times of Mg , ion concentration influenced the dialysis more profoundly than electrodialysis. With the current densities below a certain value, charge transfer efficiencies became very low and the dialysis was the main process responsible for the desalination. And the phosphate transfer from the anode chamber and potassium transfer from the cathode chamber could balance 1%–3% of the charge transfer in the MDC.

关键词: divalent ion     electrodialysis     ion characteristic     microbial desalination cell     monovalent ion    

Analysis of the dynamic hysteresis characteristic of finger seal

LEI Yanni, CHEN Guoding

《机械工程前沿(英文)》 2007年 第2卷 第1期   页码 32-36 doi: 10.1007/s11465-007-0005-y

摘要: The research about hysteresis characteristic of finger seal (FS), which was carried out based on the model with static loads, could not reflect the dynamics behavior of FS system when the rotor runs at high speed. To solve this problem, the relations between the dynamics parameters, structure parameters as well as working parameters in the system were given out through the analysis of finite element analysis result. A mass spring damper dynamics model of FS system was proposed and the hysteresis characteristic of the FS system was analyzed. This work shows that the dynamics characteristic analysis of the FS is necessary and the dynamics model proposed in this paper is valid. This dynamics model is the basis for the optimization design of FS system.

关键词: FS     necessary     hysteresis characteristic     optimization     spring    

Advancing ion-exchange membranes to ion-selective membranes: principles, status, and opportunities

《环境科学与工程前沿(英文)》 2023年 第17卷 第2期 doi: 10.1007/s11783-023-1625-0

摘要:

● IEM ion/ion selectivities of charge, valence, & specific ion are critically assessed.

关键词: Ion-exchange membranes     Selectivity     Separations    

Flow characteristic and wastewater treatment performance of a pilot-scale airlift oxidation ditch

Hongtao PANG, Hanchang SHI, Huiming SHI,

《环境科学与工程前沿(英文)》 2009年 第3卷 第4期   页码 470-476 doi: 10.1007/s11783-009-0143-z

摘要: A pilot-scale airlift oxidation ditch using bubble diffuser and baffle as aerator was operated in a wastewater treatment plant (WWTP) to investigate its flow characteristic and wastewater treatment performance. Compared with the conventional oxidation ditch process, effective depth and oxygen utilization efficiency of this new process was improved by underwater aeration. Furthermore, it had a reversed velocity distribution, which decreased from the bottom to the top on vertical section. Velocity measurement showed that a velocity over 0.2m/s at the bottom was sufficient to prevent sludge settlement during long term operation. Application of these concepts would save land area and energy consumption by about 25%―50% and 55%, respectively. In this new system, organic biodegradation and nitrification could be well achieved. Denitrification could occur steadily in the straight part by adjusting the airflow rate. An average TN removal rate of 63% was achieved with dissolved oxygen (DO) concentrations between 0.6mg/L and 1.5mg/L. The main pollutants in the effluent could meet the strictest discharge standard (COD<50mg/L, NH―N<5mg/L, and TN<15mg/L) in China now.

关键词: airlift oxidation ditch     flow characteristic     wastewater treatment    

Alumina modified sodium vanadate cathode for aqueous zinc-ion batteries

《能源前沿(英文)》   页码 775-781 doi: 10.1007/s11708-023-0902-8

摘要: Aqueous zinc-ion batteries (ZIBs) have great prospects for widespread application in massive scale energy storage. By virtue of the multivalent state, open frame structure and high theoretical specific capacity, vanadium (V)-based compounds are a kind of the most developmental potential cathode materials for ZIBs. However, the slow kinetics caused by low conductivity and the capacity degradation caused by material dissolution still need to be addressed for large-scale applications. Therefore, sodium vanadate Na2V6O16·3H2O (NVO) was chosen as a model material, and was modified with alumina coating through simple mixing and stirring methods. After Al2O3 coating modification, the rate capability and long-cycle stability of Zn//NVO@Al2O3 battery have been significantly improved. The discharge specific capacity of NVO@Al2O3 reach up to 228 mAh/g (at 4 A/g), with a capacity reservation rate of approximately 68% after 1000 cycles, and the Coulombic efficiency (CE) is close to 100%. As a comparison, the capacity reservation rate of Zn//NVO battery is only 27.7%. Its superior electrochemical performance is mainly attributed to the Al2O3 coating layer, which can increase zinc-ion conductivity of the material surface, and to some extent inhibit the dissolution of NVO, making the structure stable and improving the cyclic stability of the material. This paper offers new prospects for the development of cathode coating materials for ZIBs.

关键词: cathodes     aqueous zinc-ion batteries     sodium vanadate     alumina     coating    

Weak characteristic information extraction from early fault of wind turbine generator gearbox

Xiaoli XU, Xiuli LIU

《机械工程前沿(英文)》 2017年 第12卷 第3期   页码 357-366 doi: 10.1007/s11465-017-0423-4

摘要:

Given the weak early degradation characteristic information during early fault evolution in gearbox of wind turbine generator, traditional singular value decomposition (SVD)-based denoising may result in loss of useful information. A weak characteristic information extraction based on µ-SVD and local mean decomposition (LMD) is developed to address this problem. The basic principle of the method is as follows: Determine the denoising order based on cumulative contribution rate, perform signal reconstruction, extract and subject the noisy part of signal to LMD and µ-SVD denoising, and obtain denoised signal through superposition. Experimental results show that this method can significantly weaken signal noise, effectively extract the weak characteristic information of early fault, and facilitate the early fault warning and dynamic predictive maintenance.

关键词: wind turbine generator gearbox     µ-singular value decomposition     local mean decomposition     weak characteristic information extraction     early fault warning    

Vanadium oxide cathode with synergistic engineering of calcium-ion intercalation and polyaniline coatingfor high performance zinc-ion batteries

《化学科学与工程前沿(英文)》 2023年 第17卷 第9期   页码 1244-1253 doi: 10.1007/s11705-022-2293-5

摘要: Vanadium oxides as cathode for zinc-ion batteries have attracted much attention because of their high theoretical capacity, flexible layered structure and abundant resources. However, cathodes are susceptible to the collapse of their layered structure and the dissolution of vanadium after repeated long cycles, which worsen their capacities and cycling stabilities. Herein, a synergistic engineering of calcium-ion intercalation and polyaniline coating was developed to achieve the superior electrochemical performance of vanadium pentoxide for zinc-ion batteries. The pre-intercalation of calcium-ion between vanadium pentoxide layers as pillars increase the crystal structure’s stability, while the polyaniline coating on the cathodes improves the conductivity and inhibits the dissolution of vanadium. This synergistic engineering enables that the battery system based-on the polyaniline coated calcium vanadate cathode to deliver a high capacity of 406.4 mAh·g−1 at 1 A·g−1, an ultralong cycle life over 6000 cycles at 10 A·g−1 with 93% capacity retention and high-rate capability. The vanadium oxide cathode with synergistic engineering of calcium-ion intercalation and polyaniline coating was verified to effectively improve the electrochemical performance of zinc-ion batteries.

关键词: zinc-ion battery     CaV8O20     polyaniline coating     synergistic engineering     high capacity     long durability    

Ion-imprinted silica gel and its dynamic membrane for nickel ion removal from wastewaters

Jiehui Zeng, Jianxian Zeng, Hu Zhou, Guoqing Liu, Zhengqiu Yuan, Jian Jian

《化学科学与工程前沿(英文)》 2020年 第14卷 第6期   页码 1018-1028 doi: 10.1007/s11705-020-1915-z

摘要: An ion-imprinted sorbent (IIP) was prepared by using Ni as template, 3-[2-(2-aminoethylamino) ethylamino] propyl-trimethoxysilane as functional monomer, and silica gel as carrier. The adsorption performance of IIP towards Ni was investigated. IIP showed a higher adsorption capacity than that of non-imprinted sorbent, and it also exhibited high selectivity for Ni in the presence of Cu and Zn ions. Then, IIP was used to form a dynamic membrane onto the surface of ceramic membrane for treatment of electroplating wastewater containing Ni . Compared with ceramic membrane, IIP dynamic membrane had much higher steady membrane flux, and also rejected Ni to obtain a lower concentration of Ni in the permeate fluid. Perhaps it is suitable for future practice applications.

关键词: ion-imprinted     nickel ion     dynamic membrane     adsorption    

Fractal characteristic evaluation and interpolation reconstruction for surface topography of drilled

《机械工程前沿(英文)》 2021年 第16卷 第4期   页码 840-854 doi: 10.1007/s11465-021-0643-5

摘要: In this paper, an improved fractal interpolation model is proposed to reconstruct the surface topography of composite hole wall. This model adopts the maximum positive deviations and maximum negative deviations between the measured values and trend values to determine the contraction factors. Hole profiles in 24 directions are measured. Fractal parameters are calculated to evaluate the measured surface profiles. The maximum and minimum fractal dimension of the hole wall are 1.36 and 1.07, whereas the maximum and minimum fractal roughness are 4.05 × 10 −5 and 4.36 × 10 −10 m, respectively. Based on the two-dimensional evaluation results, three-dimensional surface topographies in five typical angles (0°, 45°, 90°, 135°, and 165°) are reconstructed using the improved model. Fractal parameter D s and statistical parameters Sa, Sq, and Sz are used to evaluate the reconstructed surfaces. Average error of D s, Sa, Sq, and Sz between the measured surfaces and the reconstructed surfaces are 1.53%, 3.60%, 5.60%, and 9.47%, respectively. Compared with the model in published literature, the proposed model has equal reconstruction effect in relatively smooth surface and is more advanced in relatively rough surface. Comparative results prove that the proposed model for calculating contraction factors is more reasonable.

关键词: surface topography     fractal evaluation     fractal interpolation     reconstruction     composite    

Operating characteristic analysis on the ultra-thin low temperature floor-heating system

Hualing ZHANG, Xiaopeng SONG

《结构与土木工程前沿(英文)》 2013年 第7卷 第2期   页码 127-132 doi: 10.1007/s11709-013-0200-3

摘要: Prefabricated ultra-thin radiant heating panel, as a new heating terminal type, is becoming a highlight in Yangtze River Valley area, China recently. However, there is a lack of operating characteristic research in this region, especially the energy consumption and operating mode are even less. To obtain these data, a heating system was set up in a duplex house in Chongqing. The test results show that the floor heating system could almost satisfy thermal comfort requirement at supply water temperature 45°C. But the preheating time was up to 4.5 h which was 1 h longer than that at supply water temperature 50°C. Meanwhile, the energy consumption at supply water temperature 50°C increased 0.10 Nm /h, and the operating efficiency decrease about 2.6% compared to those at water temperature 45°C. Considering both the thermal lag and operating efficiency, a reasonable suggestion was proposed in this paper. That was, the standard families which just stay home at night should adopt the interim mode of partial room with part time. And the supply water temperature should be properly raised during the preheating period and lowered down in the steady heating stage.

关键词: ultra-thin floor heating panel     the preheating time     thermal comfort     energy saving    

Highly selective metal recovery from spent lithium-ion batteries through stoichiometric hydrogen ion

Weiguang Lv, Xiaohong Zheng, Li Li, Hongbin Cao, Yi Zhang, Renjie Chen, Hancheng Ou, Fei Kang, Zhi Sun

《化学科学与工程前沿(英文)》 2021年 第15卷 第5期   页码 1243-1256 doi: 10.1007/s11705-020-2029-3

摘要: Spent lithium-ion battery recycling has attracted significant attention because of its importance in regard to the environment and resource importance. Traditional hydrometallurgical methods usually leach all valuable metals and subsequently extract target meals to prepare corresponding materials. However, Li recovery in these processes requires lengthy operational procedures, and the recovery efficiency is low. In this research, we demonstrate a method to selectively recover lithium before the leaching of other elements by introducing a hydrothermal treatment. Approximately 90% of Li is leached from high-Ni layered oxide cathode powders, while consuming a nearly stoichiometric amount of hydrogen ions. With this selective recovery of Li, the transition metals remain as solid residue hydroxides or oxides. Furthermore, the extraction of Li is found to be highly dependent on the content of transition metals in the cathode materials. A high leaching selectivity of Li (>98%) and nearly 95% leaching efficiency of Li can be reached with LiNi Co Mn O . In this case, both the energy and material consumption during the proposed Li recovery is significantly decreased compared to traditional methods; furthermore, the proposed method makes full use of H to leach Li . This research is expected to provide new understanding for selectively recovering metal from secondary resources.

关键词: recycling     spent LIBs     selective recovery     hydrothermal treatment    

Design and characteristic research of a novel electromechanical-hydraulic hybrid actuator with two transmission

《机械工程前沿(英文)》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0735-x

摘要: Servo-hydraulic actuators (SHAs) are widely used in mechanical equipment to drive heavy-duty mechanisms. However, their energy efficiency is low, and their motion characteristics are inevitably affected by uncertain nonlinearities. Electromechanical actuators (EMAs) possess superior energy efficiency and motion characteristics. However, they cannot easily drive heavy-duty mechanisms because of weak bearing capacity. This study proposes and designs a novel electromechanical-hydraulic hybrid actuator (EMHA) that integrates the advantages of EMA and SHA. EMHA mainly features two transmission mechanisms. The piston of the hydraulic transmission mechanism and the ball screw pair of the electromechanical transmission mechanism are mechanically fixed together through screw bolts, realizing the integration of two types of transmission mechanisms. The control scheme of the electromechanical transmission mechanism is used for motion control, and the hydraulic transmission mechanism is used for power assistance. Then, the mathematical model, structure, and parameter design of the new EMHA are studied. Finally, the EMHA prototype and test platform are manufactured. The test results prove that the EMHA has good working characteristics and high energy efficiency. Compared with the valve-controlled hydraulic cylinder system, EMHA exhibits a velocity tracking error and energy consumption reduced by 49.7% and 54%, respectively, under the same working conditions.

关键词: electromechanical-hydraulic hybrid actuator (EMHA)     integration     transmission mechanisms     power assistance     energy efficiency     working characteristics    

Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

《机械工程前沿(英文)》 2022年 第17卷 第1期   页码 9-9 doi: 10.1007/s11465-021-0665-z

摘要: Gear wear is one of the most common gear failures, which changes the mesh relationship of normal gear. A new mesh relationship caused by gear wear affects meshing excitations, such as mesh stiffness and transmission error, and further increases vibration and noise level. This paper aims to establish the model of mesh relationship and reveal the vibration characteristics of external spur gears with gear wear. A geometric model for a new mesh relationship with gear wear is proposed, which is utilized to evaluate the influence of gear wear on mesh stiffness and unloaded static transmission error (USTE). Based on the mesh stiffness and USTE considering gear wear, a gear dynamic model is established, and the vibration characteristics of gear wear are numerically studied. Comparison with the experimental results verifies the proposed dynamic model based on the new mesh relationship. The numerical and experimental results indicate that gear wear does not change the structure of the spectrum, but it alters the amplitude of the meshing frequencies and their sidebands. Several condition indicators, such as root-mean-square, kurtosis, and first-order meshing frequency amplitude, can be regarded as important bases for judging gear wear state.

关键词: gear wear     mesh relationship     mesh stiffness     transmission error     vibration characteristics    

Preparation of lithium ion-sieve and utilizing in recovery of lithium from seawater

Lu WANG, Changgong MENG, Wei MA

《化学科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 65-67 doi: 10.1007/s11705-009-0105-9

摘要: Lithium is one of the most important light metals, which is widely used as raw materials for large-capacity rechargeable batteries, light aircraft alloys and nuclear fusion fuel. Seawater, which contains 250 billion tons of lithium in total, has thus recently been noticed as a possible resource of lithium. While, since the average concentration of lithium in seawater is quite low (0.17 mg·L ), enriching it to an adequate high density becomes the primary step for industrial applications. The adsorption method is the most prospective technology for increasing the concentration of lithium in liquid. Among the adsorbents for lithium, the ion-sieve is a kind of special absorbent which has high selectivity for Li , especially the spinel manganese oxides (SMO), which among the series of ion-sieves, has become the most promising adsorption material for lithium. In this study, the SMO ion-sieve was prepared by a coprecipitation method. The preparation conditions were discussed and the sample characters were analyzed. Recovery of Li from seawater were studied in batch experiments using prepared ion-sieve, and the effect of solution pH and the uptake rates were also investigated in different Li solutions.

关键词: lithium     ion-sieve     seawater     spinel manganese oxide    

Migration of ammonium nitrogen in ion-absorbed rare earth soils during and post mining: a column study

《环境科学与工程前沿(英文)》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1702-4

摘要:

● Column experiments with an inclined slope were applied to simulate NH4–N transport.

关键词: Ion-absorbed rare earth     Ammonium nitrogen transport     HYDRUS-2D     Numerical simulation    

标题 作者 时间 类型 操作

Comparison of the removal of monovalent and divalent cations in the microbial desalination cell

Shanshan CHEN,Haiping LUO,Yanping HOU,Guangli LIU,Renduo ZHANG,Bangyu QIN

期刊论文

Analysis of the dynamic hysteresis characteristic of finger seal

LEI Yanni, CHEN Guoding

期刊论文

Advancing ion-exchange membranes to ion-selective membranes: principles, status, and opportunities

期刊论文

Flow characteristic and wastewater treatment performance of a pilot-scale airlift oxidation ditch

Hongtao PANG, Hanchang SHI, Huiming SHI,

期刊论文

Alumina modified sodium vanadate cathode for aqueous zinc-ion batteries

期刊论文

Weak characteristic information extraction from early fault of wind turbine generator gearbox

Xiaoli XU, Xiuli LIU

期刊论文

Vanadium oxide cathode with synergistic engineering of calcium-ion intercalation and polyaniline coatingfor high performance zinc-ion batteries

期刊论文

Ion-imprinted silica gel and its dynamic membrane for nickel ion removal from wastewaters

Jiehui Zeng, Jianxian Zeng, Hu Zhou, Guoqing Liu, Zhengqiu Yuan, Jian Jian

期刊论文

Fractal characteristic evaluation and interpolation reconstruction for surface topography of drilled

期刊论文

Operating characteristic analysis on the ultra-thin low temperature floor-heating system

Hualing ZHANG, Xiaopeng SONG

期刊论文

Highly selective metal recovery from spent lithium-ion batteries through stoichiometric hydrogen ion

Weiguang Lv, Xiaohong Zheng, Li Li, Hongbin Cao, Yi Zhang, Renjie Chen, Hancheng Ou, Fei Kang, Zhi Sun

期刊论文

Design and characteristic research of a novel electromechanical-hydraulic hybrid actuator with two transmission

期刊论文

Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

期刊论文

Preparation of lithium ion-sieve and utilizing in recovery of lithium from seawater

Lu WANG, Changgong MENG, Wei MA

期刊论文

Migration of ammonium nitrogen in ion-absorbed rare earth soils during and post mining: a column study

期刊论文