Langmuir最新文献

{"title":"Modulating Surfaces Hydrophobicity of Molybdenite and Galena through Sulfuric Acid Pretreatment for Efficient Flotation Separation","authors":"Jianjuan Li, Haiyun Xie, Peilun Shen, Yanling Jin, Mengfei Feng, Tuyue Guo, Dianwen Liu","doi":"10.1021/acs.langmuir.5c00888","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00888","url":null,"abstract":"Molybdenite and galena are often associated in polymetallic sulfide deposits in complex forms, and the separation of the two minerals has become a difficult and hot spot. In this article, a new method combining sulfuric acid pretreatment with flotation is proposed to realize the selective separation of molybdenite and galena. Microflotation tests were used to investigate the effect of sulfuric acid pretreatment on the floatability of molybdenite and galena. Contact angle measurement and XPS and SEM-EDS analyses revealed the mechanism of sulfuric acid pretreatment on the surface properties of molybdenite and galena. The microflotation test of single minerals results showed that sulfuric acid concentration, pretreatment temperature, and time had important effects on the surface properties of molybdenite and galena. Under the optimal conditions of sulfuric acid concentration of 3 mol/L, pretreatment temperature of 100 °C, and time of 30 min, the floatability of molybdenite was almost unaffected and still good, while galena is inhibited and almost unfloatable, which produces the largest difference in floatability between the two minerals. The test results of pretreatment-flotation separation of the molybdenite-galena mixture showed that the new process achieved efficient flotation separation of molybdenite and galena, which further confirmed the microflotation results of a single mineral. The contact angle, XPS, and SEM-EDS analyses showed that the surface of galena was oxidized to form a rough passivation layer of PbSO₄ after pretreatment, which resulted in the loss of hydrophobicity and floatability, while the surface properties of molybdenite did not change significantly before and after pretreatment. The new method of flotation separation of molybdenite and galena based on surface pretreatment provided a potential application prospect for the difficult separation of lead–molybdenum polymetallic sulfide ores.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"3 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Phosphorus Doping on Triazine- and Triazole-Based Mesoporous C3N5, C3N6, and C3N7 with Excellent Photocatalytic Hydrogen Production","authors":"Saravanan Kamalakannan, Natarajan Balasubramaniyan, Bernaurdshaw Neppolian","doi":"10.1021/acs.langmuir.5c00152","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00152","url":null,"abstract":"In recent years, little attention has been paid to triazine- and triazole-based mesoporous C₃N₅, C₃N₆, and C₃N₇, which are potential catalysts. High-N/C atomic ratio carbon nitrides (&gt;2) may possess unique electronic properties. To synthesize these nanostructures, however, many portions of the carbon nitride frameworks in the C–N have to be replaced with N–N frameworks that are thermodynamically less stable. C₃N₅, C₃N₆, and C₃N₇ are thermodynamically stable mesoporous materials synthesized from 5-amino-1<i>H</i>-tetrazole (5-AT) at 400, 300, and 250 °C. The properties of photocatalytic H₂ production from phosphorus-doped mesoporous C₃N₅, C₃N₆, and C₃N₇ were investigated for the first time with triazine and triazole units. Based on our study, we found that phosphorus (P) replaced carbon to form P–N/P═N bonds through four coordinations, which form the P 2p-level donor positions in the band gap, thereby enhancing light absorption and reducing charge separation. Photocatalytic H₂ production in P-doped mesoporous C₃N₅, C₃N₆, and C₃N₇ samples was higher than that observed in undoped mesoporous C₃N₅, C₃N₆, and C₃N₇ samples under light irradiation. According to the results, the 10MPC₃N₅ reaction rate is 637.7 μmol g^–1 h^–1, which is 6 times higher than the MC₃N₅ reaction rate. The excess phosphorus doping, however, interrupted the triazole and triazine units, reducing the efficiency of the photocatalytic H₂ reaction. P-doped mesoporous C₃N₅, C₃N₆, and C₃N₇ effectively arranged in this study can be characterized as effective, simplistic, and promising catalysts for environmental remediation and energy applications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"89 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Retraction of “Photochemical Immobilization of Proteins and Peptides on Benzophenone-Terminated Boron-Doped Diamond Surfaces”","authors":"Lionel Marcon, Mei Wang, Yannick Coffinier, Francois Le Normand, Oleg Melnyk, Rabah Boukherroub, Sabine Szunerits","doi":"10.1021/acs.langmuir.5c01161","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c01161","url":null,"abstract":"The authors retract this article (DOI: 10.1021/la903012v) due to image duplication in Figure 4B, Figure 4C, and Figure 5. The fluorescence images appear identical but have different scales, brightness levels, and color variations. The authors have agreed that such concerns raise significant doubts about the main findings of the work. As such, the article is being retracted. The original article was published on October 12, 2009, and was retracted on May 2, 2025. This article has not yet been cited by other publications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"24 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143898005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to “Study of Caesalpinia spinosa Extracts As Green Corrosion Inhibitor for Mild Steel”","authors":"Juan Hidalgo, Luis Hidalgo, Carlos Oswaldo Serrano Aguiar, Daniela Belén García Madroñero, Ildiko Galambos, Javier Ernesto Vilasó-Cadre, Ivan Alejandro Reyes-Domínguez, Adrian M. V. Brânzanic, Nicoleta Ignat, Graziella Liana Turdean","doi":"10.1021/acs.langmuir.5c01853","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c01853","url":null,"abstract":"In the original publication, the third co-author’s name appeared as Carlos Diego Serrano Aguiar. The correct name, as presented herein, is Carlos Oswaldo Serrano Aguiar. This correction does not alter the conclusions of the work. This article has not yet been cited by other publications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"8 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143901670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Water-Soluble PVA-Based Composite Films for Environmental-Friendly and Sustainable Packaging","authors":"Haohao Wang, Yunpeng Hu, Tiancheng Xiong, Dazhi Sun","doi":"10.1021/acs.langmuir.5c00876","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00876","url":null,"abstract":"This study develops a new type of poly(vinyl alcohol) (PVA) composite film by incorporating hydrophilic fumed silica and microfibrillated cellulose (MFC) as reinforcing agents through a low-cost synthesis method. The addition of these materials significantly enhanced the film’s mechanical properties and hydrophobicity. A three-dimensional network structure formed by hydrogen bonding interactions between PVA, MFC, and silica led to notable improvements in tensile strength (71.1%) and Young’s modulus (146%) in the optimal formulation with 5% MFC and 3% hydrophilic fumed silica. Additionally, the composite films exhibited a maximum water contact angle of 90.3°, indicating a significant reduction in the hydrophilicity and the development of a more hydrophobic surface. X-ray diffraction analysis confirmed that the incorporation of MFC and fumed silica enhanced the crystallinity of the PVA films, improving their structural stability. This work demonstrates the synergistic effect of MFC and hydrophilic fumed silica in PVA composite films, offering a promising solution for the development of sustainable packaging materials with improved mechanical and hydrophobic properties.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"18 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optically Triggered Nucleation Eliminates Hydration Hysteresis in Swelling Minerals","authors":"Yuntian Teng, Cheng Chen, Liange Zheng, Michael L. Whittaker","doi":"10.1021/acs.langmuir.4c04468","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04468","url":null,"abstract":"Hydration hysteresis is a ubiquitous feature of water exchange between porous solids and humid vapors. Whether one or both of the hydration hysteresis loop branches is metastable remains debated due to the many possible hydration mechanisms that can cause hysteresis. Here, we show that both endothermic and exothermic phase transitions among hydration states in smectites model compliant porous media can be optically activated during both hydration and dehydration, indicating that both branches are metastable. A net free energy difference of +15 kJ/mol of water = 6R at 298 K between adsorption and desorption branches is observed over a full hydration–dehydration loop in isothermal, isobaric hydration calorimetry. Hysteresis vanishes, and the reversible sorption energy is 5R per water molecule under continuous-wave laser illumination. In situ Raman spectra confirm that hydrogen bonding between water and structural hydroxyl in the metal oxide framework screens the interlayer charge, weakening interactions and releasing heat. The latent heat of hydration is stored in this immobilized water, which provides the mechanical dilation necessary to nucleate distinct hydration states when water vibrational modes are optically activated. Our findings show that water sorption hysteresis is caused by delicate interfacial phase transitions, which visible light at ambient levels is sufficient to promote. These findings may have important consequences for the fate of sorbents, such as carbon, mineral nutrients, and environmental contaminants associated with clays in soils since the retention and mobility of these species depends strongly on the hydration state of the mineral surface.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"24 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fabrication and Characterization of Bimetallic Silica-Based and 3D-Printed Active Colloidal Cubes","authors":"Silvana A. Caipa Cure, Daniela J. Kraft","doi":"10.1021/acs.langmuir.5c00815","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00815","url":null,"abstract":"Simulations on self-propelling active cubes reveal interesting behaviors at both the individual and the collective level, emphasizing the importance of developing experimental analogues that allow testing these theoretical predictions. The majority of experimental realizations of active colloidal cubes rely on light actuation and/or magnetic fields to have a persistent active mechanism and lack material versatility. Here, we propose a system of active bimetallic cubes whose propulsion mechanism is based on a catalytic reaction and study their behavior. We realize such a system from synthetic silica cuboids and 3D-printed microcubes, followed by the deposition of gold and platinum layers on their surface. We characterize the colloids’ dynamics for different thicknesses of the gold layer at low and high hydrogen peroxide concentrations. We show that the thickness of the base gold layer has only a minor effect on the self-propulsion speed and, in addition, induces a gravitational torque during sedimentation. For low activity, this gravitational torque orients the particles such that their velocity director is pointing out of the plane, thus effectively suppressing propulsion. We find that a higher active force can remedy the effects of torque, resulting in all possible particle orientations, including one with the metal cap on the side, which is favorable for in-plane propulsion. Finally, we use 3D printing to compare our results to cubes made from a different material, size, and roundness and demonstrate that the speed scaling with increasing particle size originates from the size-dependent drag. Our experiments extend the fabrication of active cubes to different materials and propulsion mechanisms and highlight that the design of active particles with anisotropic shapes requires consideration of the interplay between shape and activity to achieve favorable sedimentation and efficient in-plane propulsion.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"22 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143901689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Furmidge Equation Revisited","authors":"Yotam Stern, Rafael Tadmor, Assaf Miron, Appu Vinod","doi":"10.1021/acs.langmuir.5c01302","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c01302","url":null,"abstract":"This paper addresses the issue of the discontinuous function that gives rise to the Furmidge equation, a long-standing problem in interfacial science. The force at the contact line of a sliding drop is related to the drop size, the contact angle hysteresis, the surface tension, and a geometrical prefactor <i>k</i> which depends on the distribution of the contact angle about the contact line. The most common expression for the contact line force, called the Furmidge equation, takes <i>k</i> = 1 and is based on a discontinuous contact line, while corrections to this model pose polynomial functional forms for the contact angle, engendering discontinuities in the derivatives. Moreover, experimental findings provide a wide range of <i>k</i> values for different drops on different solids, and this range is yet to be explained in a physical context. Owing to this, the understanding of forces on sliding drops remains lacking. We construct a general model based on a Fourier series, and we further generalize this model by superposing a series of Gaussian curves on our Fourier series. The result of this model is a range of <i>k</i> values, in accordance to the range of experimental values which appear in the literature. Additionally, we fit our functional form for the contact angle to experimental data and find good agreement, as well as good agreement between <i>k</i> values.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"21 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variant Properties of Tungsten Species over CeO2 Induced by Different Lattice Planes for the Selective Catalytic Reduction of Nitric Oxide","authors":"Jin Yuan, Jinxing Mi, Weitao Zhao, Ke Zheng, Shaoqi Zhou, Jianjun Chen","doi":"10.1021/acs.langmuir.5c00644","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00644","url":null,"abstract":"Although ceria-based catalysts have been proven to be a promising alternative to conventional vanadyl catalysts for the selective catalytic reduction of NO<i>_<i>x</i></i> with NH₃ (NH₃–SCR), whether the interaction between tungsten (W) and CeO₂ could be well established for enhancing SCR performance is still unclear. Herein, W/CeO₂ catalysts with different CeO₂ morphologies for SCR are fully investigated. Systematic characterization results confirmed that the crystalline WO₃ phase was formed on W-loaded CeO₂ nanocubes, nanospindles, and nanospheres. Intriguingly, the W/CeO₂ nanorods exhibited exclusively polymeric tungstate species. This divergence originates from the distinct W-CeO₂ interaction mediated by preferentially exposed {110} lattice planes, endowing the nanorod catalyst with stronger reducibility, more surface-active oxygen species, and acid sites. Consequently, the NH₃–SCR activity followed the order W/CeO₂ nanorods &gt; W/CeO₂ nanospindles &gt; W/CeO₂ nanocubes &gt; W/CeO₂ nanospheres. This work reveals the significant role of the CeO₂ morphology in the dispersion and interaction of W species, which directly influences the NH₃–SCR performance. The insight offers a valuable opportunity for the design of a more efficient SCR catalyst.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"35 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143893809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced Charge Transfer Kinetics in Hematite Photoanodes via Au Nanoclusters─Toward Efficient Light-Driven Hydrogen Generation","authors":"Aleksandra Szkudlarek, Kamila Kollbek, Krzysztof Mech, Krzysztof Maćkosz, Mateusz Marzec, Vitaliy Bilovol, Marcin Sikora","doi":"10.1021/acs.langmuir.4c04843","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04843","url":null,"abstract":"In these studies, we explain the mechanism by which gold nanoparticles enhance the photoelectrochemical activity of thin films of hematite. The electrodes were manufactured using magnetron sputtering in combination with inert gas condensation, one of the most advanced techniques to decorate the top material layer with metallic nanoclusters. Adjusting the very low surface concentration of widely separated Au nanoclusters, corresponding to 2.3% surface coverage, we observed a 2-fold increase in photocurrent values. This effect can be explained by electrochemical impedance spectroscopy results, which show an increase in charge carriers density by 1.7 and charge carriers lifetime by 1.4. Comprehensive in-depth microscopic and spectroscopic studies of the morphological, chemical, and electronic properties of hematite allow not only the characterization of the material but also the determination of the role of metallic Au nanoclusters at the electrode–electrolyte interface. Understanding the mechanism of the interactions between hematite and metallic Au nanoclusters is a key factor in designing advanced sustainable devices for solar-to-chemical energy conversion.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"53 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143897724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}