The aim of the paper is to present a promising approach for recycling high value-added metals from the cathode materials of spent LIBs. The synthesis process of NCM cathode material enlightened us to ...apply reduction roasting to break LiNixCoyMnzO2 into simple compounds or metals. Accordingly, the effect of several factors such as temperature, carbon dosage and roasting time is assessed on the leaching efficiency of valuable metals. The roasted products are analyzed by XRD and SEM-EDS, and the results show that the cathode material after reduction roasting is primarily transformed into Li2CO3, Ni, Co and MnO. However, the solubility of Li2CO3 is relatively low, so carbonated water leaching is used to treat the roasted products. Then the filtrate is evaporated for the preparation of pure Li2CO3, and residue is leached to recycle other metals with H2SO4. The results indicate that, after roasted at 650 °C for 3 h with 19.9% carbon dosage, 84.7% Li is preferentially recovered via carbonated water leaching, and more than 99% Ni, Co and Mn are recycled via acid leaching without adding reductant. Finally, the products of Li2CO3, NiSO4, CoSO4 and MnSO4 are obtained. The process have great potential for industrial-scale recycling from spent LIBs.
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•A simple and efficient process is proposed for recovering spent LIBs.•LiNixCoyMnzO2 was transformed into Li2CO3, Ni, Co and MnO by reduction roasting.•Carbonated water leaching was used to selectively recover Li from roasted products.•Co, Ni and Mn were efficiently leached by H2SO4 solution without adding reductant.•The products of Li2CO3, NiSO4, CoSO4 and MnSO4 were obtained.
A combined process was presented to recover valuable metals from lithium nickel cobalt manganese (NCM) cathodes of spent lithium-ion batteries. In this process, the cathode scrap was first roasted ...with carbonaceous reductant, and then carbonation water leaching was employed to selectively extract Li from the roasted cathodes. Finally, the obtained residue was leached in sulfuric acid solution to recover Co, Ni and Mn. A systematic investigation combining thermodynamic analysis, leaching experiments and characterization was conducted to explore the effect of operating conditions and leaching mechanism. The results indicate that the leaching of Li is significantly improved by injecting of CO2 into the leaching system, and more than 80% of Li can be leached within 10 min at a low liquid-solid ratio. High-quality Li2CO3 can be prepared from the leachate by direct evaporation. More than 96% of Ni, Co and Mn are extracted without adding reductant under the conditions of a H2SO4 dosage of 1.15 times the theoretical value, a time of 2.5 h, a temperature of 55 °C and a liquid-solid ratio of 3.5 mL g−1. The acid leaching process is more efficient and economical, which is ascribed to the transformation of the low-valence states of metals with high activity after reduction roasting.
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•An efficient and economical process was proposed for recovering spent LIBs.•Over 85% of Li was selectively extracted at a low L/S ratio by carbonation leaching.•High-quality Li2CO3 was prepared via direct evaporation of carbonation leachate.•More than 98% of Ni, Mn and 96% of Co were leached without adding reductant.•Leaching mechanism of Co, Ni and Mn was explained by thermodynamic calculation.
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•The formation of water-insoluble LiAlO2 led to a decrease in the Li leaching.•About 88% of Li was preferentially extracted by carbonation water leaching.•More than 98% of Ni, Co and ...Mn were acid-leached without reducing agent.•Battery-grade Li2CO3 was prepared via direct evaporation of carbonation leachate.•A preliminary economic analysis of proposed process was performed.
Recycling of spent lithium-ion batteries becomes increasingly important due to the presence of valuable metals and great harm to the environment. In this work, a combined method of reduction roasting with methane, carbonation water leaching and acid leaching was proposed to recover valuable metals from spent lithium-ion batteries. Firstly, thermodynamic analysis was applied to predict the reaction products after reduction roasting. It indicates that the presence of Al will lead to the formation of water-insoluble LiAlO2. Then, pre-alkali leaching was used to preferentially separate Al to facilitate the Li leaching. The effects of roasting temperature, time and methane flow rate on reduction roasting have been further studied. The results show that under the optimal roasting conditions (temperature: 600 °C, time: 30 min, methane flow rate: 300 mL/min), about 88% of Li can be preferentially extracted and over 98% of Mn, Ni and Co are subsequently acid-leached without the employment of reducing agent. Additionally, the removal of organic matters during the roasting process decreases the concentration of F, P and COD in the leachate and further reduces the cost of wastewater treatment. Finally, the preliminary economic analysis of proposed process confirms that the process has high potential for the industrial production.
In this paper, the reduced graphene oxide and multiwall carbon nanotubes hybrid materials (RGO–MWNTs) were prepared and a novel strategy for the simultaneous determination of multiple environmental ...contaminations has been proposed on the basis of RGO–MWNTs hybrid materials modified electrode. The hybrid materials were characterized by the scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and N2 sorption–desorption isotherms. Due to the excellent catalytic activity, enhanced electrical conductivity, high surface area and porous structure of the RGO–MWNTs, the RGO–MWNTs/GCE achieved the simultaneous measurement of hydroquinone (HQ), catechol (CC), p-cresol (PC) and nitrite (NO2−) with well-separate four peaks. Scheme 1a illuminated the preparation process of the RGO–MWNTs hybrid materials. Scheme 1b explains the electron mediating properties of RGO–MWNTs/GCE towards the oxidation of HQ, CC, PC and NO2−. Scheme 1c presented the SEM image of RGO–MWNTs hybrid materials. Scheme 1d and e showed the 2D and 3D AFM images of RGO–MWNTs films, respectively. Display omitted
► The novel RGO–MWNTs hybrid materials were synthesized. ► The simultaneous detection of four environmental contaminations was achieved. ► SEM, AFM, XPS was employed to characterize the RGO–MWNTs hybrid materials.
In this paper, the reduced graphene oxide and multiwall carbon nanotubes hybrid materials (RGO–MWNTs) were prepared and a strategy for detecting environmental contaminations was proposed on the basis of RGO–MWNTs modified electrode. The hybrid materials were characterized by the scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and N2 sorption–desorption isotherms. Due to the excellent catalytic activity, enhanced electrical conductivity and high surface area of the RGO–MWNTs, the simultaneous measurement of hydroquinone (HQ), catechol (CC), p-cresol (PC) and nitrite (NO2−) with four well-separate peaks was achieved at the RGO–MWNTs modified electrode. The linear response ranges for HQ, CC, PC and NO2− were 8.0–391.0μM, 5.5–540.0μM, 5.0–430.0μM and 75.0–6060.0μM, correspondingly, and the detection limits (S/N=3) were 2.6μM, 1.8μM, 1.6μM and 25.0μM, respectively. The outstanding film forming ability of RGO–MWNTs hybrid materials endowed the modified electrode enhanced stability. Furthermore, the fabricated sensor was applied for the simultaneous determination of HQ, CC, PC and NO2− in the river water sample.
Medical image-to-image translation is considered a new direction with many potential applications in the medical field. The medical image-to-image translation is dominated by two models, including ...supervised Pix2Pix and unsupervised cyclic-consistency generative adversarial network (GAN). However, existing methods still have two shortcomings: 1) the Pix2Pix requires paired and pixel-aligned images, which are difficult to acquire. Nevertheless, the optimum output of the cycle-consistency model may not be unique. 2) They are still deficient in capturing the global features and modeling long-distance interactions, which are critical for regions with complex anatomical structures. We propose a Swin Transformer-based GAN for Multi-Modal Medical Image Translation, named MMTrans. Specifically, MMTrans consists of a generator, a registration network, and a discriminator. The Swin Transformer-based generator enables to generate images with the same content as source modality images and similar style information of target modality images. The encoder part of the registration network, based on Swin Transformer, is utilized to predict deformable vector fields. The convolution-based discriminator determines whether the target modality images are similar to the generator or from the real images. Extensive experiments conducted using the public dataset and clinical datasets showed that our network outperformed other advanced medical image translation methods in both aligned and unpaired datasets and has great potential to be applied in clinical applications.
Radiotherapy (RT) in practical use often suffers from off-target side effects and ineffectiveness against hypoxic tumor microenvironment (TME) as well as remote metastases. With regard to these ...problems, herein, we provide semiconductor heterojunction structured WO2.9-WSe2-PEG nanoparticles to realize a synergistic RT/photothermal therapy (PTT)/checkpoint blockade immunotherapy (CBT) for enhanced antitumor and antimetastatic effect. Based on the heterojunction structured nanoparticle with high Z element, the nanosystem could realize non-oxygen-dependent reactive oxygen species generation by catalyzing highly expressed H2O2 in TME upon X-ray irradiation, which could further induce immunogenic cell death. Meanwhile, this nanosystem could also induce hyperthermia upon near-infrared irradiation to enhance RT outcome. With the addition of anti-PD-L1 antibody-based CBT, our results give potent evidence that local RT/PTT upon mild temperature and low radiation dose could efficiently ablate local tumors and inhibit tumor metastasis as well as prevent tumor rechallenge. Our study provides not only one kind of radiosensitizer based on semiconductor nanoparticles but also a versatile nanoplatform for simultaneous triple-combined therapy (RT/PTT/CBT) for treating both local and metastasis tumors.
Recycling spent lead-acid batteries has always been a research hotspot. Although traditional pyrometallurgical smelting is still the dominant process, it has serious environmental drawbacks, such as ...the emission of lead dust and SO2, and high energy consumption. This study presents a clean process for recycling spent lead-acid battery paste. The lead in paste was recovered via hydrometallurgical leaching and electrowinning in chloride solution. The leaching ratio of lead was >99% under optimum conditions: temperature of 90 °C, CaCl2 concentration of 400 g/L, Fe2+ concentration of 5 g/L, pH 1.0, and leaching time of 2 h. The appropriate minimum Pb concentration and optimum current density for electrowinning were determined to be 10 g/L and 200 A/m2, respectively. Cathode lead powders with a purity of 99.6% were obtained via electrowinning. The current efficiency and the power consumption at 200 A/m2 were 96.3% and 85.9 kWh per ton of lead produced, respectively. Due to the use of soluble anode (iron), the energy consumption of the electrowinning process was considerably reduced and the chlorine evolution was avoided. The electrowinning has obvious economic advantages over cementation, and the metallic lead with high purity can be obtained using this method. Furthermore, as the spent electrolyte containing ferrous ions is recyclable, the consumption of reagents and the liquid effluent are minimised. The final leaching residue is a mixture of harmless akaganeite and calcium sulphate. The experimental results show that the proposed process is promising for the recovery of lead from spent lead-acid battery paste.
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•Lead paste was recovered via leaching and electrowinning in chloride solution.•The leaching of lead was over 99% and the current efficiency was 96.3%.•The energy consumption of the electrowinning was only 85.9 kWh/t Pb.•The spent electrolyte was recyclable and the chlorine evolution was avoided.•No desulfurization step is required in the novel process.
Background
Low signal‐to‐noise ratio (SNR) has been a major limiting factor for the application of higher‐resolution diffusion‐weighted imaging (DWI). Most of the conventional denoising models suffer ...from the drawbacks of shallow feature extraction and hand‐crafted parameter tuning. Although multiple studies have shown the promising applications of image denoising using convolutional neural networks (CNNs), none of them have considered denoising multiple b‐value DWIs using a multichannel CNN model.
Purpose
To present a joint denoising CNN (JD‐CNN) model to improve the SNR of multiple b‐value DWI.
Study Type
Retrospective technical development.
Population
Twenty healthy rats and two rats with clinically confirmed focal cortical dysplasia were included to evaluate the performance of the proposed method.
Field Strength/Sequence
11.7T MRI, a multiple b‐values DWI sequence.
Assessment
The total variation (TV) and BM3D denoising methods were also performed on the same dataset for comparison. Peak SNR (PSNR) and normalized mean square error (NMSE) were calculated for the assessment of image qualities.
Statistical Tests
A paired Student's t‐test was conducted to compare the diffusion parameter measurements between different approaches. P < 0.01 was considered statistically significant.
Results
Simulation results showed substantial improvement of image quality after JD‐CNN denoising (PSNR of original image: 23.15 ± 1.77; PSNR of denoised image: 42.94 ± 2.12). The proposed method outperforms the state‐of‐the‐art methods on high b‐value DWIs in terms of PSNR (TV: 33.51 ± 0.83, BM3D: 35.12 ± 0.94, JD‐CNN: 46.52 ± 0.98). In addition, the NMSE of the estimated apparent diffusion coefficient (ADC) reduces from 0.72 ± 0.13 to 0.45 ± 0.06 (P < 0.01) with the application of the JD‐CNN model.
Data Conclusion
The proposed method is able to remove noise with a wide range of noise levels in multiple b‐value DWI and improve the diffusion parameter estimation. This shows potential clinical promise.
Level of Evidence: 2
Technical Efficacy Stage: 2
J. Magn. Reson. Imaging 2019;50:1937–1947.
The extraction of Ni from limonitic laterite by the NAPL (nitric acid pressure leaching) process has received significant attention. However, how to achieve continuous and suitable acid–base ...regeneration restricts the industrialization of the NAPL process. In this paper, spray pyrolysis technology promises to solve this problem. Hence, the phase evolution of the sample during the spray pyrolysis was studied, which is Mg(NO
3
)
2
·6H
2
O → Mg(NO
3
)
2
·2H
2
O → Mg
3
(OH)
4
(NO
3
)
2
→ MgO. Raman spectra of Mg
3
(OH)
4
(NO
3
)
2
were recorded for the first time and further prove the conclusion of the phase evolution. In addition, the thermal analysis of the critical intermediate product (Mg
3
(OH)
4
(NO
3
)
2
) was performed, which indicates that the endothermic in the pyrolysis process is 194.35 kJ/mol, and is divided into two stages. The two stages both include the process of dehydration and denitration and the amount of dehydration and denitration in the second stage is relatively small. The reaction rate of stage two is slow and the temperature requirement is higher. Thermodynamic calculation results show that the R3 and An models could describe the whole process well. The related kinetic equations were obtained and the thermal stability of Mg
3
(OH)
4
(NO
3
)
2
was predicted. Based on the above research, a two-step pyrolysis process is proposed by combining spray pyrolysis (~ 823 K) and calcining pyrolysis (≥ 693 K, 0.5 ~ 1.5 h). This route is simple, efficient, and continuous, which is conducive to industrialization and can successfully reduce at least 58.31% of NOx entering the compressor, thereby making the compressor smaller and less electricity consumption.
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