ACS Engineering Au最新文献

{"title":"Electrocoagulation Process for Recovery of Precious Metals from Cyanide Leachates Using a Low Voltage","authors":"Juan Carlos Soto-Uribe*,&nbsp;Jesus Leobardo Valenzuela-Garcia*,&nbsp;Maria Mercedes Salazar-Campoy*,&nbsp;José Refugio Parga-Torres,&nbsp;Víctor Manuel Vazquez-Vazquez,&nbsp;Martin Antonio Encinas-Romero and Guadalupe Martinez-Ballesteros,&nbsp;","doi":"10.1021/acsengineeringau.3c00041","DOIUrl":"10.1021/acsengineeringau.3c00041","url":null,"abstract":"<p >The cyanidation of gold ores with copper content is frequent in gold mines. Copper affects the performance and profits of mineral processing. The current technology for gold recovery from cyanide solutions usually involves the adsorption of the gold-cyanide complex ion on activated carbon; however, the copper affects this process. The process of electrocoagulation (EC) is a promising technique for gold and silver recovery with copper, where all of the metals can be recovered. This work used the electrocoagulation process (EC) to evaluate the metal recovery from a pregnant leach solution (PLS), where EC is a promising technique. This study aimed to determine the optimal parameter to recover the gold and silver and to see the effect of copper concentration in the PLS obtained by simultaneous pressure leaching/oxidation of a gold-bearing pyritic concentrate. EC tests were run to recover gold and silver over copper from PLS using aluminum electrodes and variables like distances between electrodes, pH, potential applied, and feeding flow for continuous EC. The chemical assay of cyanide leachates shows a concentration of 7.15 mg/L of gold, 305 mg/L of silver, and 351.5 mg/L of copper with 1810 mg/L of free cyanide. The results showed that the EC process recovered 99% of gold and copper and 92% of silver at a pH of 11, 8 mm of dE, and a potential applied 3 V in 10 min. However, under this condition in continuous EC with a flow rate of 40 mL/min, the recovery is 66.3% of gold, 85.8% of silver, and 45.3% of copper; compared with the batch process, the gold and silver decrease.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.3c00041","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138493036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanism of the Direct Reduction of Chromite Process as a Clean Ferrochrome Technology","authors":"Dogan Paktunc*,&nbsp;Jason P. Coumans,&nbsp;David Carter,&nbsp;Nail Zagrtdenov and Dominique Duguay,&nbsp;","doi":"10.1021/acsengineeringau.3c00057","DOIUrl":"10.1021/acsengineeringau.3c00057","url":null,"abstract":"<p >Direct reduction of chromite (DRC) is a promising alternative process for ferrochrome production with the potential to significantly reduce energy consumption and greenhouse gas emissions compared to conventional smelting. In DRC, chromium (Cr) and iron (Fe) from chromite ore incongruently dissolve into a molten salt, which facilitates mass transfer to a carbon (C) reductant where in situ metallization occurs. Consequently, ferrochrome is produced below the slag melting temperatures, achieving substantial energy savings relative to smelting. However, there are significant knowledge gaps in the kinetics, Cr solubility, speciation, and coordination environment which are critical to understanding the fundamental mechanisms of molten salt-assisted carbothermic reactions. To address these knowledge gaps, we performed pyrometallurgical experiments with variable temperature and residence times and analyzed the composition of chromite, ferrochrome, and slag products along with determining the speciation of Cr. Our results indicate that the DRC mechanism can be explained by the following sequential steps: (1) incongruent dissolution of chromite, (2) reduction of dissolved Cr in molten salt/slag, (3) transport of Cr and Fe species in molten media, and (4) reduction on C particles and metallization as Cr–Fe alloys. The discovery of four types of reduced Cr species in the slag indicates that the reduction of Cr³⁺ to Cr²⁺ and Cr⁰ occurred in the molten phase before metallization on solid carbon particles. Thermodynamically, the reduction of CrO(<i>l</i>) to Cr metal is more feasible at a lower temperature than it is for Cr₂O₃(<i>l</i>) corroborating the accelerated reduction efficiency of the DRC process.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.3c00057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138496579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carbon Dioxide Capture, Utilization, and Sequestration: Current Status, Challenges, and Future Prospects for Global Decarbonization","authors":"Srinu Nagireddi,&nbsp;Jatin R. Agarwal* and Damodaran Vedapuri,&nbsp;","doi":"10.1021/acsengineeringau.3c00049","DOIUrl":"10.1021/acsengineeringau.3c00049","url":null,"abstract":"<p >This Review provides an in-depth overview of carbon dioxide (CO₂) capture, utilization, and sequestration (CCUS) technologies and their potential in global decarbonization efforts. The Review discusses the concept of CO₂ utilization, including conversion to fuels, chemicals, and minerals as well as biological processes. It also explores the different types of CO₂ sequestration, including geological, ocean, and mineral storage, and the associated challenges and opportunities such as regulatory issues and public acceptance. The Review highlights the potential of integrating CO₂ CCUS technologies and presents case studies of successful projects. The benefits and limitations of these technologies are discussed, along with areas for further research and development. Overall, this Review underscores the importance of CCUS.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.3c00049","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138496581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Review of Traditional and Intensified Hydrometallurgy Techniques to Remove Chromium and Vanadium from Solid Industrial Waste","authors":"Aya Saidi,&nbsp;Rebecca El Khawaja and Daria C. Boffito*,&nbsp;","doi":"10.1021/acsengineeringau.3c00046","DOIUrl":"10.1021/acsengineeringau.3c00046","url":null,"abstract":"<p >The continuous growth of industrial activities, driven by economic expansion and technological advancements, has increased industrial waste generation. These wastes often contain hazardous substances, including heavy metals. Their improper disposal has become a significant environmental and health concern, necessitating global attention. To address this issue and mitigate the scarcity and cost of raw materials, recycling waste materials has emerged as a viable solution, particularly in the synthesis of construction materials. Various methods, such as pyrometallurgical and hydrometallurgical techniques, have been established for recycling industrial waste. This Review focuses on hydrometallurgical techniques, specifically targeting the separation of two highly toxic heavy metals: chromium and vanadium. It comprehensively explores various hydrometallurgical methods, including acid, alkaline, organic, and oxidative leaching, for solid waste materials. Additionally, this Review highlights several intensified leaching processes assisted by electrical fields, supercritical fluids, plasma, microwaves, and ultrasound. The presented methods offer promising approaches to effectively manage industrial waste.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.3c00046","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138496582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Production of Sustainable Low-Layer Graphene by Green Synthesis at Room Conditions for Platinum-Based Direct Methanol Fuel Cell","authors":"Vildan Erduran,&nbsp;Ramazan Bayat,&nbsp;Iskender Isik,&nbsp;Tugba Bayazit and Fatih Şen*,&nbsp;","doi":"10.1021/acsengineeringau.3c00040","DOIUrl":"10.1021/acsengineeringau.3c00040","url":null,"abstract":"<p >In this study, a cost-effective and scalable method for the production of low-layer graphene (LLG) using sodium percarbonate (SPC) as a green delamination agent and its application in fuel cells is proposed. The obtained graphene showed a decrease in signal height in XRD analysis, indicating thinner layers. Raman analysis confirmed the presence of 7–8 layers of graphene. Field-emission scanning electron microscopy analysis revealed a uniform crystal structure, making it suitable for various applications. Direct methanol fuel cells (DMFCs) are widely recognized as efficient and environmentally friendly devices for converting chemical energy to electrical energy. The utilization of graphene-supported platinum (Pt) nanoparticles (NPs) as catalysts in DMFCs enhances their performance. In this study, Pt-graphene catalysts were synthesized by the chemical reduction method with graphene obtained by using SPC. Characterization through XRD and SEM analyses confirmed the homogeneous distribution of NPs on the carbon support. As a result of methanol oxidation studies, 57.73 and 21.45 mA/cm² values were obtained by using Pt@LLG and Pt catalysts, respectively. As a result of long-term stability and durability tests, it has been found that the Pt@LLG catalyst can be used effectively in metal oxidation experiments.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.3c00040","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138496580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"QRChEM: A Deep Learning Framework for Materials Property Prediction and Design Using QR Codes","authors":"Haripriyan Uthayakumar,&nbsp;Rahul Krishna K,&nbsp;Raj Jain,&nbsp;Rajnish Kumar and Tarak K. Patra*,&nbsp;","doi":"10.1021/acsengineeringau.3c00055","DOIUrl":"10.1021/acsengineeringau.3c00055","url":null,"abstract":"<p >Machine learning (ML) surrogate models are used for the rapid prediction of materials properties and are promising tools for accelerating new materials design and development. The performance and accuracy of these surrogate models appear to be intricately connected to the molecular representation that is employed. Developing efficient numerical representations of molecules is vital for the success of surrogate models in predicting materials' properties. Here, we propose a new machine-readable molecular representation, namely a molecular quick response (QR) code, for the deep learning of materials structure–property correlations. We built a convolutional deep neural network (CNN) model based on molecular QR codes, which is abbreviated as QRChEM. QRChEM was trained and validated using ∼21 000 data for four representative properties of small molecules, namely specific heat, enthalpy, zero-point vibrational energy, and HOMO–LUMO band gap. We show that QRChEM outperforms the commonly used Morgan fingerprint-based and one-hot encoding (OHE)-based deep learning frameworks. We further performed UMAP (uniform manifold approximation and projection) on the molecular QR codes to demonstrate the differentiability of the molecular topologies, which is vital for high-fidelity surrogate model development.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.3c00055","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138496578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Competing Effects of Molecular Additives and Cross-Link Density on the Segmental Dynamics and Mechanical Properties of Cross-Linked Polymers","authors":"Wenjian Nie,&nbsp;Jack F. Douglas* and Wenjie Xia*,&nbsp;","doi":"10.1021/acsengineeringau.3c00043","DOIUrl":"10.1021/acsengineeringau.3c00043","url":null,"abstract":"<p >The introduction of molecular additives into thermosets often results in changes in their dynamics and mechanical properties that can have significant ramifications for diverse applications of this broad class of materials such as coatings, high-performance composites, <i>etc</i>. Currently, there is limited fundamental understanding of how such additives influence glass formation in these materials, a problem of broader significance in glass-forming materials. To address this fundamental problem, here, we employ a simplified coarse-grained (CG) model of a polymer network as a model of thermoset materials and then introduce a polymer additive having the same inherent rigidity and polymer–polymer interaction strength as the cross-linked polymer matrix. This energetically “neutral” or “self-plasticizing” additive model gives rise to non-trivial changes in the dynamics of glass formation and provides an important theoretical reference point for the technologically more important case of interacting additives. Based on this rather idealized model, we systematically explore the combined effect of varying the additive mass percentage (<i>m</i>) and cross-link density (<i>c</i>) on the segmental relaxation dynamics and mechanical properties of a model thermoset material with additives. We find that increasing the additive mass percentage <i>m</i> progressively decreases both the glass-transition temperature <i>T</i>_g and the fragility of glass formation, a trend <i>opposite</i> to increasing <i>c</i> so that these thermoset variables clearly have a <i>competing effect</i> on glass formation in these model materials. Moreover, basic mechanical properties (<i>i.e.</i>, bulk, shear, and tensile moduli) likewise exhibit a competitive variation with the increase of <i>m</i> and <i>c</i>, which are strongly correlated with the Debye–Waller parameter ⟨<i>u</i>²⟩, a measure of material stiffness at a molecular scale. Our findings prove beneficial in the development of structure–property relationships for the cross-linked polymers, which could help guide the design of such network materials with tailored physical properties.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.3c00043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135242811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Joule-Heated Catalytic Reactors toward Decarbonization and Process Intensification: A Review","authors":"Lei Zheng,&nbsp;Matteo Ambrosetti and Enrico Tronconi*,&nbsp;","doi":"10.1021/acsengineeringau.3c00045","DOIUrl":"10.1021/acsengineeringau.3c00045","url":null,"abstract":"<p >The supply of the heat required for chemical processes via renewable electricity, i.e., process electrification, provides an alternative strategy for replacing conventional fossil fuel combustion. This approach enables fast, selective, and uniform heating, offers great potential for utilizing the excess renewable electric energy, and brings about an important chance for mitigating CO₂ emissions. In this work, we provide an overview of the state-of-the-art electricity-to-heat driven catalytic processes. The principle and fundamentals of Joule heating are provided and briefly compared to induction and microwave heating in view of electrifying catalytic processes. By this comparison, we assess that Joule heating can be regarded as the most promising method for process electrification, and its applications to methane reforming, cracking reactions, CO₂ valorization, and transient process operation are then reviewed. Advantages and disadvantages are critically addressed in terms of efficiency, potential for scale-up and possibility of retrofitting. The current challenges in the development of advanced electrified processes as well as the opportunities of next generation electrification techniques are discussed.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.3c00045","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135590165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Semiautomated Experiments to Accelerate the Design of Advanced Battery Materials: Combining Speed, Low Cost, and Adaptability","authors":"Eric McCalla*,&nbsp;","doi":"10.1021/acsengineeringau.3c00037","DOIUrl":"10.1021/acsengineeringau.3c00037","url":null,"abstract":"<p >A number of methodologies are currently being exploited in order to dramatically increase the composition space explored in the design of new battery materials. This is proving necessary as commercial Li-ion battery materials have become increasingly high-performing and complex. For example, commercial cathode materials have quinary compositions with a sixth element in the coating, while a very large number of contenders are still being considered for solid electrolytes, with most of the periodic table being at play. Furthermore, the promise of accelerated design by computation and machine learning (ML) are encouraging, but they both ultimately require large amounts of quality experimental data either to fill in holes left by the computations or to be used to improve the ML models. All of this leads researchers to increase experimental throughputs. This perspective focuses on semiautomated experimental approaches where automation is only utilized in key steps where absolutely necessary in order to overcome bottlenecks while minimizing costs. Such workflows are more widely accessible to research groups as compared to fully automated systems, such that the current perspective may be useful to a wide community. The most essential steps in automation are related to characterization, with X-ray diffraction being a key bottleneck. By analyzing published workflows of both semi- and fully automated workflows, it is found herein that steps handled by researchers during the synthesis are not prohibitive in terms of overall throughput and may lead to greater flexibility, making more synthesis routes possible. Examples will be provided in this perspective of workflows that have been optimized for anodes, cathodes, and electrolytes in Li batteries, the vast majority of which are also suitable for battery technologies beyond Li.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.3c00037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135774689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decarbonization of Agriculture: The Greenhouse Gas Impacts and Economics of Existing and Emerging Climate-Smart Practices","authors":"Kamila Kazimierczuk*,&nbsp;Sarah E. Barrows*,&nbsp;Mariefel V. Olarte and Nikolla P. Qafoku,&nbsp;","doi":"10.1021/acsengineeringau.3c00031","DOIUrl":"10.1021/acsengineeringau.3c00031","url":null,"abstract":"<p >The worldwide emphasis on reducing greenhouse gas (GHG) emissions has increased focus on the potential to mitigate emissions through climate-smart agricultural practices, including regenerative, digital, and controlled environment farming systems. The effectiveness of these solutions largely depends on their ability to address environmental concerns, generate economic returns, and meet supply chain needs. In this Review, we summarize the state of knowledge on the GHG impacts and profitability of these three existing and emerging farming systems. Although we find potential for CO₂ mitigation in all three approaches (depending on site-specific and climatic factors), we point to the greater level of research covering the efficacy of regenerative and digital agriculture in tackling non-CO₂ emissions (i.e., N₂O and CH₄), which account for the majority of agriculture’s GHG footprint. Despite this greater research coverage, we still find significant methodological and data limitations in accounting for the major GHG fluxes of these practices, especially the lifetime CH₄ footprint of more nascent climate-smart regenerative agriculture practices. Across the approaches explored, uncertainties remain about the overall efficacy and persistence of mitigation─particularly with respect to the offsetting of soil carbon sequestration gains by N₂O emissions and the lifecycle emissions of controlled environment agriculture systems compared to traditional systems. We find that the economic feasibility of these practices is also system-specific, although regenerative agriculture is generally the most accessible climate-smart approach. Robust incentives (including carbon credit considerations), investments, and policy changes would make these practices more financially accessible to farmers.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.3c00031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135818123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}