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1.
Biomed Instrum Technol ; 54(5): 346-351, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-33049766

RESUMO

Electroencephalography (EEG) is a sensitive and weak biosignal that varies from person to person. It is easily affected by noise and artifacts. Hence, maintaining the signal integrity to design an EEG acquisition system is crucial. This article proposes an analog design for acquiring EEG signals. The proposed design consists of eight blocks: (1) a radio-frequency interference filter and electro-static discharge protection, (2) a preamplifier and second-order high-pass filter with feedback topology and an unblocking mechanism, (3) a driven right leg circuit, (4) two-stage main and variable amplifiers, (5) an eight-order anti-aliasing filter, (6) a six-order 50-Hz notch filter (optional), (7) an opto-isolator circuit, and (8) an isolated power supply. The maximum gain of the design is approximately 94 dB, and its bandwidth ranges from approximately 0.18 to 120 Hz. The depth of the 50-Hz notch filter is -35 dB. Using this filter is optional because it causes EEG integrity problems in frequencies ranging from 40 to 60 Hz.


Assuntos
Amplificadores Eletrônicos , Eletroencefalografia , Artefatos , Fontes de Energia Elétrica , Desenho de Equipamento/métodos
2.
Chemosphere ; 254: 126869, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957283

RESUMO

This paper presents the results of Co(II) and Ni(II) extraction from model and real solutions using bis(2,4,4-trimethylpentyl)phosphinic acid (i.e. Cyanex 272) that are in agreement with waste-to-resources approach, i.e. the recovery of valuable components from wastes. The results from this study shows that, extraction using Cyanex 272 is an efficient method to recover Co(II) selectively from sulfate electrolytes obtained from the leaching of steel scraps of aircraft engines. The highest selectivity value (∼160) of Co(II) extraction over Ni(II) was obtained at a pH of 4.8, the lowest selectivity value (∼30) was observed at a pH of 5.5, while above this value the selectivity only increased slightly with increasing pH. A pH of 5.2 was selected as a compromise between Co(II) selectivity and Ni(II) amount in the organic phase. The essence of the investigation is to propose important parameters to extract Co(II) from real leach solutions, and to further recover valuable Co(II) from the loaded organic phase by stripping with 1 M H2SO4, thus producing an electrolyte of Co(II) for electrowinning - a possible alternative route for resource recovery. Small volume of the stripping phase (w/o = 1:5) used in this study, lead to an enrichment of sulfate electrolyte in Co(II), resulting in ∼50 g/dm3 of Co(II) in the solution, which is a great advantage of the approach proposed. Such a solution is a valuable source for the electrowinning of metallic cobalt, which can be used for the production of steel alloys, Li-ion batteries or catalysts.


Assuntos
Cobalto/química , Modelos Químicos , Níquel/química , Ácidos Fosfínicos/química , Fontes de Energia Elétrica , Lítio , Sulfatos
3.
S Afr Med J ; 110(7): 652-656, 2020 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-32880342

RESUMO

BACKGROUND: Ingestion of foreign bodies remains a frequent reason for presentation to paediatric emergency departments worldwide. Among the variety of objects ingested, button batteries are particularly harmful owing to their electrochemical properties, which can cause extensive injuries if not diagnosed and treated rapidly. International trends show an increasing incidence of button battery ingestion, leading to concern that this pattern may be occurring in South Africa. Limited local data on paediatric foreign body ingestion have been published. OBJECTIVES: To assess battery ingestion rates in a tertiary paediatric hospital. We hypothesised that the incidence has increased, in keeping with international trends. Secondary objectives included describing admission rates, requirements for anaesthesia and surgery, and promoting awareness of the problems associated with battery ingestion. METHODS: We performed a retrospective, descriptive analysis of the Red Cross War Memorial Children's Hospital trauma database, including all children under 13 years of age seen between 1 January 2010 and 31 December 2015 with suspected ingestion of a foreign body. The ward admissions database was then examined to find additional cases in which children were admitted directly. After exclusion of duplicate records, cases were classified by type of foreign body, management, requirement for admission, anaesthesia and surgery. Descriptive statistics were used to analyse the data in comparison with previous studies published from this database. RESULTS: Patient age and gender patterns matched the literature, with a peak incidence in children under 2 years of age. Over the 6-year period, 180 patients presented with food foreign bodies, whereas 497 objects were classified as non-food. After exclusion of misdiagnosed cases, the remaining 462 objects were dominated by coins (44.2%). Batteries were the causative agent in 4.8% (22/462). Although the subtypes of batteries were not reliably recorded, button batteries accounted for at least 64% (14/22). Most children who ingested batteries presented early, but more required admission, anaesthesia and surgery than children who ingested other forms of foreign body. CONCLUSIONS: The study demonstrated that the local incidence of button battery ingestion may be increasing, although data are still limited.Admission, anaesthesia and surgery rates for batteries were higher in this cohort than for all other foreign bodies. As button batteries can mimic coins, with much more dire consequences on ingestion, our ability to expedite diagnosis and management hinges on a high index of suspicion. It is imperative to increase awareness among healthcare workers and parents.


Assuntos
Fontes de Energia Elétrica/estatística & dados numéricos , Corpos Estranhos/epidemiologia , Adolescente , Distribuição por Idade , Criança , Pré-Escolar , Bases de Dados Factuais , Fontes de Energia Elétrica/efeitos adversos , Corpos Estranhos/cirurgia , Humanos , Incidência , Lactente , Recém-Nascido , Estudos Retrospectivos , África do Sul/epidemiologia , Centros de Atenção Terciária
4.
Waste Manag ; 115: 113-120, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32736031

RESUMO

Liberation and reduction of cathode material are the necessary procedures for improving the recycling efficiency of cathode material derived from spent lithium-ion batteries. In this research work, a pyrolysis technology was utilized to remove the organic binder and enhance liberation of electrode materials. At the same time, pyrolysis treatment can facilitate the thermal-reduction of Co3+ in LiCoO2 to Co2+ with surface organics, which lays a foundation for the subsequent reductant-free acid leaching. Results indicate that the crystal structure of pure LiCoO2 is not changed at a pyrolysis temperature of 600 °C, but LiCoO2 transforms to CoO, Li2CO3, LiF, and Li2O under the reduction action of HF, pyrolytic carbon, and additive carbon black. Water-impact crushing is synchronized with water-leaching to separate electrode materials from aluminum foil and recover Li element. Afterwards, reductant-free acid leaching technology can be utilized to recycle Li and Co from spent LiCoO2 batteries. Recovery efficiency of Li element in water-leaching process was up to 92.17% while the remaining 7.83% of Li and all Co elements were recovered during reductant-free acid leaching process. Based on the foundation analysis, the green chemical process for recovering valuable metals from spent lithium-ion batteries was proposed.


Assuntos
Fontes de Energia Elétrica , Lítio , Eletrodos , Metalurgia , Reciclagem
5.
J Emerg Manag ; 18(4): 295-309, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32804398

RESUMO

OBJECTIVE: Benchmark the economic value of renewable energy and battery storage systems to extend operation of certain critical infrastructure facilities in different markets. DESIGN: This study uses the renewable energy optimization model to assess three critical facilities in North Caro-lina. Techno-economic results were then compared to analyses completed for critical facilities in California and New York to assess energy system cost effectiveness. RESULTS: Though solar photovoltaic (PV) arrays are cost-effective across each of the three North Carolina facili-ties, adopting battery storage to enable PV to operate with existing diesel generators in a hybrid energy system re-duces the economic value of the system. This is in contrast to more economically viable systems in California and New York. All of these systems also offer unquantified resilience benefits by extending operation from hours to weeks across the facilities. CONCLUSION: If decision makers were able to value the resilience benefits offered by each system or utility rate structures were changed to incentivize battery storage during normal operations, it would impact these assessments. Even so, this analysis provides decision makers a key set of cost benchmarks when considering how they might im-prove resilience at their critical operations.


Assuntos
Planejamento em Desastres , Fontes de Energia Elétrica , Energia Renovável , Humanos , New York , North Carolina
6.
PLoS One ; 15(8): e0237169, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32797059

RESUMO

Compared to the integer-order modeling, the fractional-order modeling can achieve higher accuracy for designing and analyzing the DC-DC power converters. However, its applications in pulse width modulation (PWM) converters are limited due to the computational complexities. In this paper, a modified fractional-order modeling methodology for DC-DC converters is proposed, and its effectiveness is verified on the fractional-order positive Luo converters. Instead of using fractional-order calculus, the proposed methodology analyzes the harmonic components of the PWM converters by utilizing the non-linear vector differential equations of the periodically time-variant system. The final solution of the state variables is composed of two parts: the steady-state solution and the transient solution. The approximate steady state solution can be obtained by using the equivalent small parameter (ESP) method and the harmonic balance theory, while the main part of the transient solution can be obtained according to the explicit Grünwald-Letnikov (GL) approximation. In addition, the influence of the fractional orders on the performance of the DC-DC converters, and on the dynamic behaviors of the fractional-orders systems are also discussed in this paper. Compared to the conventional fractional-order numerical models, the proposed model is able to present the time-domain information more precisely, which helps to better reveal and analyze the non-linear behaviors of the DC-DC converters. The effectiveness of the work is demonstrated by the simulation and experimental results of the equivalent circuits built with fractional-order components.


Assuntos
Fontes de Energia Elétrica , Modelos Teóricos , Algoritmos , Simulação por Computador
7.
PLoS One ; 15(8): e0236409, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32853253

RESUMO

This paper proposes an alternative approach to extract transformer's winding parameters of resistance (R), inductance (L), capacitance (C) and conductance (G) based on Finite Element Method (FEM). The capacitance and conductance were computed based on Fast Multiple Method (FMM) and Method of Moment (MoM) through quasi-electrostatics approach. The AC resistances and inductances were computed based on MoM through quasi-magnetostatics approach. Maxwell's equations were used to compute the DC resistances and inductances. Based on the FEM computed parameters, the frequency response of the winding was obtained through the Bode plot function. The simulated frequency response by FEM model was compared with the simulated frequency response based on the Multi-conductor Transmission Line (MTL) model and the measured frequency response of a 33/11 kV, 30 MVA transformer. The statistical indices such as Root Mean Square Error (RMSE) and Absolute Sum of Logarithmic Error (ASLE) were used to analyze the performance of the proposed FEM model. It is found that the simulated frequency response by FEM model is quite close to measured frequency response at low and mid frequency regions as compared to simulated frequency response by MTL model based on RMSE and ASLE analysis.


Assuntos
Capacitância Elétrica , Fontes de Energia Elétrica , Análise de Elementos Finitos , Simulação por Computador , Condutividade Elétrica , Eletricidade Estática
8.
PLoS One ; 15(8): e0236929, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32797050

RESUMO

Accurate dosimetry for a real wireless power transfer system (WPT) using electromagnetic resonance and electromagnetic induction requires an accurate description of the field formed by the system. In particular, the electromagnetic field depends on factors such as the construction of the transmitting and receiving coils, the circuit configuration, the input source of the front end of the transmitting coil, and the input impedance of the rear end of receiving coil. However, both circuit and electromagnetic simulations need to be performed to analyze the entire system, which is a difficult task. In order to overcome this difficulty, a method using an equivalent circuit model is proposed and verified through experiments. Moreover, the worst exposure condition to a magnetic field was examined by considering three variables: the charging mode, the state of charge, and the alignment and misalignment between the transmitting and receiving coils. Accordingly, the strongest magnetic field was created in the constant current mode in the fully charged state with misalignment. For example, the magnetic field strength in the case of 80% state of charge and misalignment was 1.397 times greater than in the case of 20% state of charge and alignment at a point 10 mm from the transmission pad. Finally, the induced electric fields and induced current densities were calculated by using a Japanese adult male whole-body voxel human model, and the results were compared with the values recommended by international guidelines to ascertain their compliance.


Assuntos
Fontes de Energia Elétrica , Exposição Ambiental/análise , Tecnologia sem Fio , Humanos , Radiometria
9.
Lab Chip ; 20(19): 3560-3568, 2020 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-32844858

RESUMO

A miniaturized polymerase chain reaction (PCR) system is not only important for medical applications in remote areas of developing countries, but also important for testing at ports of entry during global epidemics, such as the current outbreak of the coronavirus. Although there is a large number of PCR sensor systems available for this purpose, there is still a lack of portable digital PCR (dPCR) heating systems. Here, we first demonstrated a portable plasmonic heating-based dPCR system. The device has total dimensions of 9.7 × 5.6 × 4.1 cm and a total power consumption of 4.5 W, allowing for up to 25 dPCR experiments to be conducted on a single charge of a 20 000 mAh external battery. The dPCR system has a maximum heating rate of 10.7 °C s-1 and maximum cooling rate of 8 °C s-1. Target DNA concentrations in the range from 101 ± 1.4 copies per µL to 260 000 ± 20 000 copies per µL could be detected using a poly(dimethylsiloxane) (PDMS) microwell membrane with 22 080 well arrays (20 µm diameter). Furthermore, the heating system was demonstrated using a mass producible poly(methyl methacrylate) PMMA microwell array with 8100 microwell arrays (80 µm diameter). The PMMA microwell array could detect a concentration from 12 ± 0.7 copies per µL to 25 889 ± 737 copies per µL.


Assuntos
Reação em Cadeia da Polimerase/instrumentação , Algoritmos , Técnicas Biossensoriais , DNA/química , Fontes de Energia Elétrica , Humanos , Membranas Artificiais , Miniaturização , Polimetil Metacrilato
10.
Int J Occup Environ Med ; 11(3): 140-147, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32683426

RESUMO

BACKGROUND: The major portion of lead in the body resides in skeletal system. The bone turnover affects the release of lead into the circulation from bones. The bone turnover biomarkers (BTM) in lead-battery workers with long-term exposure to lead have not been explored yet. OBJECTIVE: To evaluate the BTM (formation and resorption) in lead-battery workers with long-term exposure to lead in lead-battery manufacturing plant. METHODS: 176 male lead-exposed workers and 80 matched comparison group were studied. All participants were examined for blood lead levels (BLLs), bone formation biomarkers- serum osteocalcin (OC), alkaline phosphatase (ALP), bone-specific alkaline phosphatase (BALP)-and bone resorption biomarkers-serum pyridinoline (PYD), deoxypyridinoline (DPYD), tartarate-resistant acid phosphatase-5b (TRACP-5b), and urinary hydroxyproline (UHYP). RESULTS: We found a significantly higher bone formation biomarkers such as BALP (p=0.007) and bone resorption biomarkers, eg, PYD (p=0.048), TRCAP-5b (p=0.001), and UHYP (p=0.001) in lead-exposed workers. A significant (p=0.041) negative correlation (ρ ­0.128) was noted between BLLs and OC. A significant positive correlation was noted between BLLs and TRACP-5b (ρ 0.176, p=0.005) and UHYP (ρ 0.258, p=0.004). Serum OC (p=0.040) and UHYP (p=0.015) levels changed significantly with BLL level. Bone resorption biomarkers levels- PYD, TRACP-5b, and BALP-were higher among those with higher BLLs levels. The duration of exposure was significantly associated with BALP (p=0.037), DPYD (p=0.016), TRACP-5b (p=0.001), and UHYP (p=0.002) levels. CONCLUSION: Long-term lead exposure affects the bone turnover.


Assuntos
Biomarcadores/sangue , Remodelação Óssea/fisiologia , Fontes de Energia Elétrica , Chumbo/toxicidade , Exposição Ocupacional/análise , Fosfatase Ácida/sangue , Fosfatase Ácida/metabolismo , Adulto , Fosfatase Alcalina/sangue , Biomarcadores/análise , Reabsorção Óssea/sangue , Estudos de Casos e Controles , Estudos Transversais , Fontes de Energia Elétrica/efeitos adversos , Humanos , Isoenzimas/sangue , Isoenzimas/metabolismo , Chumbo/química , Intoxicação por Chumbo/sangue , Intoxicação por Chumbo/diagnóstico , Masculino , Instalações Industriais e de Manufatura , Pessoa de Meia-Idade , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/estatística & dados numéricos , Osteocalcina/sangue , Local de Trabalho
11.
Proc Natl Acad Sci U S A ; 117(31): 18292-18301, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32661158

RESUMO

Pencils and papers are ubiquitous in our society and have been widely used for writing and drawing, because they are easy to use, low-cost, widely accessible, and disposable. However, their applications in emerging skin-interfaced health monitoring and interventions are still not well explored. Herein, we report a variety of pencil-paper-based on-skin electronic devices, including biophysical (temperature, biopotential) sensors, sweat biochemical (pH, uric acid, glucose) sensors, thermal stimulators, and humidity energy harvesters. Among these devices, pencil-drawn graphite patterns (or combined with other compounds) serve as conductive traces and sensing electrodes, and office-copy papers work as flexible supporting substrates. The enabled devices can perform real-time, continuous, and high-fidelity monitoring of a range of vital biophysical and biochemical signals from human bodies, including skin temperatures, electrocardiograms, electromyograms, alpha, beta, and theta rhythms, instantaneous heart rates, respiratory rates, and sweat pH, uric acid, and glucose, as well as deliver programmed thermal stimulations. Notably, the qualities of recorded signals are comparable to those measured with conventional methods. Moreover, humidity energy harvesters are prepared by creating a gradient distribution of oxygen-containing groups on office-copy papers between pencil-drawn electrodes. One single-unit device (0.87 cm2) can generate a sustained voltage of up to 480 mV for over 2 h from ambient humidity. Furthermore, a self-powered on-skin iontophoretic transdermal drug-delivery system is developed as an on-skin chemical intervention example. In addition, pencil-paper-based antennas, two-dimensional (2D) and three-dimensional (3D) circuits with light-emitting diodes (LEDs) and batteries, reconfigurable assembly and biodegradable electronics (based on water-soluble papers) are explored.


Assuntos
Eletrônica/instrumentação , Grafite , Monitorização Fisiológica/instrumentação , Pele , Dispositivos Eletrônicos Vestíveis , Fontes de Energia Elétrica , Eletrodos , Desenho de Equipamento , Humanos , Papel
12.
Waste Manag ; 114: 166-173, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32679474

RESUMO

An environmentally benign leaching process for recovering valuable metals from the cathodes of spent lithium-ion batteries was developed. Glucose oxidase produced by Aspergillus niger can oxidize glucose to give the leaching agent gluconic acid. The presence of gluconic acid was proven by mass spectrometry. The cathode material morphology was characterized by X-ray diffractometry and scanning electron microscopy, and the efficiencies with which valuable metals were leached from the Li(NixCoyMnz)O2 material were determined by inductively coupled plasma optical emission spectroscopy. More than 95% of the Co, Li, Mn, and Ni were leached from spent lithium-ion batteries using a solid/liquid ratio of 30 g/L, 1 M gluconic acid leaching solution, a 1 vol% H2O2 reductant solution, a temperature of 70 °C, and a reaction time of 80 min. The leaching kinetics were perfectly described by the Avrami equation. The apparent activation energies for leaching of Li, Ni, Co, and Mn were determined as 41.76, 42.84, 43.59, and 45.35 kJ/mol, respectively, indicating that the surface chemical reaction is the rate-controlling step during this leaching process. This mild biocatalysis-aided acid leaching process is a promising method for effectively recovering valuable metals from spent lithium-ion batteries.


Assuntos
Glucose Oxidase , Lítio , Biocatálise , Fontes de Energia Elétrica , Peróxido de Hidrogênio , Metais , Reciclagem
13.
Waste Manag ; 114: 253-262, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32682090

RESUMO

Recycling of spent lithium-ion batteries (LIBs) has drawn considerable attention in recent years, as an economic solution to the resource shortage. Selective ammonia leaching is recognized as an economical and environment-friendly method, yet it is difficult to separate and reuse the valuable metals from the leachate. In this study, we proposed an NH3-(NH4)2CO3-Na2SO3 leaching system to selectively recover the valuable metals from commercial LiNixCoyMn1-x-yO2 (NCM) and spent NCM. For single-stage leaching, 79.1% of the lithium, 86.4% of the cobalt, and 85.3% of the nickel were selectively leached under optimal conditions, and a mere 1.45% of the manganese was dissolved in the solution. The leaching process in the NH3-(NH4)2CO3-Na2SO3 system was consistent with the surface chemical reaction control model. For multistage leaching, almost all metals (98.4% of the lithium, 99.4% of the cobalt, 97.3% of the nickel) could be leached and a high-purity (>99%) MnCO3 product was simultaneously obtained. The introduction of CO32- not only led to the production of MnCO3 with wide application prospects, but also greatly reduced the consumption of the reducing agent. This study is thus beneficial for recycling of the valuable metals and synthesis of the MnCO3 product from the spent LIBs.


Assuntos
Lítio , Manganês , Amônia , Carbonatos , Fontes de Energia Elétrica , Metais , Reciclagem
14.
PLoS One ; 15(6): e0234992, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32603382

RESUMO

Renewable energy resources connected to a single utility grid system require highly nonlinear control algorithms to maintain efficient operation concerning power output and stability under varying operating conditions. This research work presents a comparative analysis of different adaptive Feedback Linearization (FBL) embedded Full Recurrent Adaptive NeuroFuzzy (FRANF) control schemes for maximum power point tracking (MPPT) of PV subsystem tied to a smart microgrid hybrid power system (SMG-HPS). The proposed schemes are differentiated based on structure and mathematical functions used in FRANF embedded in the FBL model. The comparative analysis is carried out based on efficiency and performance indexes obtained using the power error between the reference and the tracked power for three cases; a) step change in solar irradiation and temperature, b) partial shading condition (PSC), and c) daily field data. The proposed schemes offer enhanced convergence compared to existing techniques in terms of complexity and stability. The overall performance of all the proposed schemes is evaluated by a spider chart of multivariate comparable parameters. Adaptive PID is used for the comparison of results produced by proposed control schemes. The performance of Mexican hat wavelet-based FRANF embedded FBL is superior to the other proposed schemes as well as to aPID based MPPT scheme. However, all proposed schemes produce better results as compared to conventional MPPT control in all cases. Matlab/Simulink is used to carry out the simulations.


Assuntos
Algoritmos , Fontes de Energia Elétrica , Energia Solar , Simulação por Computador , Eletrodos , Retroalimentação , Modelos Lineares , Temperatura
15.
Environ Sci Pollut Res Int ; 27(32): 40205-40209, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32661975

RESUMO

Thermal treatment offers an alternative method for the separation of Al foil and cathode materials during spent lithium-ion batteries (LIBs) recycling. In this work, the pyrolysis behavior of cathode from spent LIBs was investigated using advanced thermogravimetric Fourier transformed infrared spectroscopy coupled with gas chromatography-mass spectrometer (TG-FTIR-GC/MS) method. The fate of fluorine present in spent batteries was probed as well. TG analysis showed that the cathode decomposition displayed a three-stage process. The temperatures of maximum mass loss rate were located at 470 °C and 599 °C, respectively. FTIR analysis revealed that the release of CO2 increased as the temperature rose from 195 to 928 °C. However, the evolution of H2O showed a decreasing trend when the temperature increased to above 599 °C. The release of fluoride derivatives also exhibited a decreasing trend, and they were not detected after temperatures increasing to above 470 °C. GC-MS analysis indicated that the release of H2O and CO displayed a similar trend, with larger releasing intensity at the first two stages. The evolution of 1,4-difluorobenzene and 1,3,5-trifluorobenzene also displayed a similar trend-larger releasing intensity at the first two stages. However, the release of CO2 showed a different trend, with the largest release intensity at the third stage, as did the release of 1,2,4-trifluorobenzene, with the release mainly focused at the temperature of 300-400 °C. The release intensities of 1,2,4-trifluorobenzene and 1,3,5-trifluorobenzene were comparable, although smaller than that of 1,4-difluorobenzene. This study will offer practical support for the large-scale recycling of spent LIBs.


Assuntos
Lítio , Pirólise , Fontes de Energia Elétrica , Eletrodos , Cromatografia Gasosa-Espectrometria de Massas , Reciclagem , Espectroscopia de Infravermelho com Transformada de Fourier
16.
Chemosphere ; 260: 127500, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32688308

RESUMO

Lithium (Li+) is used in various applications involving pharmaceuticals, textile dyes, and batteries. Therefore, the demand for environmentally friendly and effective materials for Li+ uptake and recovery continues to increase. Herein, rice husk (RH) and coconut shell (CS) biomasses were used to fabricate honeycomb-networked biochar (BC) precursors via slow pyrolysis. RHBC- and CSBC-based MnO2 composites were synthesized by depositing MnO2 in various ratios onto RHBC and CSBC by varying the KMnO4 concentration (2%, 3%, and 4%), followed by simple ultrasonication and heat-treatment methodologies. The structural and physicochemical properties of all of the fabricated composites were analyzed using several different instrumental methods. The batch adsorption experiments were performed for comparative Li+-adsorption studies of RHBC-Mnx and CSBC-Mnx composites by optimizing several parameters (pH, adsorbent dose, Li+ initial concentration, and contact time). The comparative adsorption analysis revealed that the RHBC-Mnx composites exhibited stronger Li+-adsorption ability than the CSBC-Mnx composites and that increasing the MnO2 deposition to 3% in both cases led to maximum Li+ adsorption capacities (62.85 mg g-1 and 57.8 mg g-1), respectively. The kinetic studies show that Li+ adsorption proceeds through the pseudo-second-order mechanism. Li+ recovery was successfully carried out using HCl (eluting agent), thereby demonstrating the benefits of synthesized composites at the industrial scale. The current work indicates that the fabricated RHBC-Mnx and CSBC-Mnx composites may have potential for use as economical composites in eco-friendly applications such as Li+ adsorption and recovery from aqueous media.


Assuntos
Carvão Vegetal/química , Cocos/química , Lítio/análise , Compostos de Manganês/química , Oryza/química , Óxidos/química , Poluentes Químicos da Água/análise , Adsorção , Fontes de Energia Elétrica , Íons , Cinética , Resíduos Sólidos/análise
17.
J Chromatogr A ; 1624: 461258, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32540083

RESUMO

Lithium ion batteries are essential power sources in portable electronics, electric vehicles and as energy storage devices for renewable energies. During harsh battery cell operation as well as at elevated temperatures, the electrolyte decomposes and inter alia organo(fluoro)phosphates are formed due to hydrolysis of the conducting salt lithium hexafluorophosphate (LiPF6). Since these phosphorus-containing decomposition products possess a potential toxicity based on structural similarities compared to chemical warfare agents, quantification is of high interest regarding safety estimates. In this study, two comprehensive approaches for the precipitation of highly concentrated PF6¯ were investigated, allowing the separation from target analytes (organo(fluoro)phosphates) and improving mass spectrometry-based quantification techniques. Trimethyl phosphate was used as a polar, non-acidic organophosphate reference substance for method development via liquid chromatography-mass spectrometry. Six solvents were examined regarding precipitation reaction and selectivity. Thermally degraded electrolytes were analyzed after precipitation by means of gas chromatography-flame ionization detector, demonstrating the applicability of the developed sample preparations. The optimized method was applied successfully without influencing any volatile and non-acidic decomposition products. Using optimized conditions, a precipitation rate of 98% PF6¯ was achieved. Consequently, a fast and easy sample preparation for gas chromatographic investigations on lithium ion battery electrolytes was implemented, applicable for routine analysis.


Assuntos
Cromatografia Gasosa/métodos , Fontes de Energia Elétrica , Eletrólitos/química , Lítio/química , Organofosfatos/análise , Precipitação Química , Cromatografia Líquida de Alta Pressão , Íons , Organofosfatos/química , Solventes/química
18.
Environ Monit Assess ; 192(7): 419, 2020 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-32506209

RESUMO

Wind energy has been used by humans for thousands of years. Yet, the relatively low economic cost and availability of fossil fuels upstaged the use of wind power. Fossil fuel resources are not renewable and will decline until exhaustion in the future. At the same time, humans have become aware of the adverse effects on the environment caused by reliance on fossil fuel energy. Wind, on the other hand, is a renewable energy source with minimal adverse environmental impacts that does not involve greenhouse gas emissions. Agricultural irrigation systems use fossil fuel energy resources in various forms. Groundwater withdrawal is central to supplying agricultural water demand in arid and semi-arid regions. Such withdrawal is mostly based on water extraction with pumps powered by diesel, gasoline, or electricity (which is commonly produced by fossil fuels). This paper coupled the non-sorted genetic algorithm (NSGA-II) as the optimization tool to the mathematical formulation of the wind-powered groundwater production problem to determine the potential of wind energy for groundwater withdrawal in an arid area. The optimal safe yield and the optimal size of regulation reservoir are determined considering two objectives: (1) maximizing total extraction of groundwater and (2) minimizing the cost of reservoir construction. The safe yield and the two objectives are optimized for periods lasting 1, 2, 3, 4, and 6 months over a 1-year planning horizon. This paper's methodology is evaluated with groundwater and wind-power data pertinent to Eghlid, Iran. The optimal safe yield increases by increasing the period length. Specifically, increasing the period length from 1 to 6 months increases the safe yield from 12 to 29 m3. Application of the proposed NSGA-II-based optimization of groundwater production identifies the best design and operational variables with computational efficiency and accuracy.


Assuntos
Fontes de Energia Elétrica , Água Subterrânea , Vento , Irã (Geográfico)
19.
Waste Manag Res ; 38(8): 911-920, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32552572

RESUMO

The consumption of lithium iron phosphate (LFP)-type lithium-ion batteries (LIBs) is rising sharply with the increasing use of electric vehicles (EVs) worldwide. Hence, a large number of retired LFP batteries from EVs are generated annually. A recovery technology for spent LFP batteries is urgently required. Compared with pyrometallurgical, hydrometallurgical and biometallurgical recycling technologies, physical separating technology has not yet formed a systematic theory and efficient sorting technology. Strengthening the research and development of physical separating technology is an important issue for the efficient use of retired LFP batteries. In this study, spent LFP batteries were discharged in 5 wt% sodium chloride solution for approximately three hours. A specially designed machine was developed to dismantle spent LFP batteries. Extending heat treatment time exerted minimal effect on quality loss. Within the temperature range of 240°C-300°C, temperature change during heat treatment slightly affected mass loss. The change in heat treatment temperature also had negligible effect on the shedding quality of LFP materials. The cathode material and the aluminium foil current collector accounted for a certain proportion in a sieve with a particle size of -1.25 + 0.40 mm. Corona electrostatic separation was performed to separate the metallic particles (with a size range of -1.5 + 0.2 mm) from the nonmetallic particles of crushed spent LFP batteries. No additional reagent was used in the process, and no toxic gases, hazardous solid waste or wastewater were produced. This study provides a complete material recovery process for spent LFP batteries.


Assuntos
Fontes de Energia Elétrica , Lítio , Eletrodos , Ferro , Fosfatos , Reciclagem
20.
Waste Manag ; 113: 32-40, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32505109

RESUMO

To recycle the sharply growing spent lithium-ion batteries and alleviate concerns over shortages of resources, particularly Li, is still an urgent issue. In this work, an organic acids based leaching approach at room temperature is proposed to recover Li and FePO4 from spent LiFePO4 cathode powder. The coexistent metal ions, Cu and Al, have also been investigated. Citrus fruit juices, rich in organic acids, such as citric acid and malic acid, have been used as leaching agents in this work. Among lemon, orange and apple, lemon juice shows the best leaching effect based on its suitable pH of the reaction system. Under the optimized conditions, the leaching rates of Li, Cu and Al can reach up to 94.83%, 96.92% and 47.24%, while Fe and P remain as low as 4.05% and 0.84%, respectively. Li2CO3 and FePO4 can be recovered from the leachate and the leaching residue, respectively. The recovered FePO4 was used to prepare new cathode material LiFePO4. The crystalline carbon, present in the spent LiFePO4 cathode scraps, has a significant effect on the electrochemical performances of the regenerated LiFePO4. The regenerated LiFePO4 cathode material delivered a comparable discharge capacity of 155.3 mAh g-1 at 0.1C and rate capacity to the fresh LiFePO4. For the cycling stability, it displays capacity retention of 98.30% over 100 cycles at 1 C with a fading rate of 0.017% per cycle. The proposed organic acids-based recycling strategy is much benign for recycling the spent LiFePO4 cathode materials.


Assuntos
Fontes de Energia Elétrica , Lítio , Eletrodos , Íons , Reciclagem
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