scholarly journals New Combined Depressant/Collectors System for the Separation of Powellite from Dolomite and the Interaction Mechanism

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 291
Author(s):  
Yunlou Qian ◽  
Wei Ding ◽  
Zhen Wang ◽  
Yang Peng
Keyword(s):  
Active Site ◽  
Photoelectron Spectroscopy ◽  
Energy Analysis ◽  
Interaction Mechanism ◽  
X Ray ◽  
Benzohydroxamic Acid ◽  
Site Density ◽  
Saline Minerals ◽  
Flotation Beneficiation ◽  
Mineral Interaction

The flotation beneficiation of powellite from dolomite was achieved with a new reagent system that consists of a mixed collector of sodium oleate (NaOl) and benzohydroxamic acid (BHA) and a depressant sodium hexametaphosphate (SHMP). The interaction mechanism of the reagent regime with minerals was studied using zeta potential and X-ray photoelectron spectroscopy (XPS) detection together with crystal chemistry and interaction energy analysis. The matching features of O–O distance in BHA with that in saline minerals and active site density/activity were used as methods to explain the reagent/mineral interaction. The results of microflotation finally established the new reagent regime at pH 8–12: 2.5 × 10−4 M SHMP, 2 × 10−4 M mixed collector containing 1.5 × 10−4 M NaOl and 0.5 × 10−4 M BHA. SHMP selectively depresses the adsorption of NaOl and BHA onto dolomite but minimally affects the adsorption of NaOl and BHA on the powellite surface.

scholarly journals Synthesis of 1-(2-Hydroxyphenyl) Dec-2-en-1-One Oxime and Its Flotation and Adsorption Behavior for Malachite

2020 ◽  
Vol 8 ◽  
Author(s):  
Liqing Li ◽  
Lin Yang ◽  
Fangxu Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Adsorption Behavior ◽  
Xps Analysis ◽  
X Ray ◽  
Benzohydroxamic Acid ◽  
Wide Ph Range ◽  
Flotation Performance ◽  
Ph Range

A novel collector of 1-(2-hydroxyphenyl) dec-2-en-1-one oxime (HPDO) was synthesized from 2-hydroxy acetophenone and octanal, and its flotation and adsorption behavior for malachite were studied by flotation tests and x-ray photoelectron spectroscopy (XPS) analysis. The flotation results of a single mineral show HPDO is a special collector for malachite. Compared with benzohydroxamic acid (BHA), isobutyl xanthate (SIBX), and dodecylamine (DA), HPDO exhibits excellent flotation performance for malachite and satisfied selectivity against quartz and calcite over a wide pH range. The HPDO with a concentration of 200 mg/L can float 94% malachite at pH 8, while only recovering 7.8% quartz and 28% calcite. XPS data give clear evidence for the formation of a Cu-oxime complex on malachite surfaces after HPDO adsorption.

scholarly journals One-Step Reinforcement and Deacidification of Paper Documents: Application of Lewis Base—Chitosan Nanoparticle Coatings and Analytical Characterization

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1226
Author(s):  
Zhihui Jia ◽  
Chun Yang ◽  
Fangnan Zhao ◽  
Xiaolian Chao ◽  
Yuhu Li ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chitosan Nanoparticles ◽  
Antibacterial Properties ◽  
Interaction Mechanism ◽  
Accelerated Aging ◽  
Natural Aging ◽  
Lewis Base ◽  
X Ray ◽  
Chitosan Nanoparticle ◽  
One Step

To delay acidification and deterioration during natural aging, deacidification and reinforcement of paper manuscripts have been the most important technologies to prolong the life of objects. Herein, a novel approach for the conservation of paper manuscripts is proposed using chitosan nanoparticles as Lewis base that leads to both deacidification and strengthening of paper in one-step. Chitosan nanoparticles were prepared through physical ball grinding method and characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analyzer (LPSA), Fourier transform infrared spectroscopy (FTIR), and atomic force microscope (AFM). To evaluate the resistance of chitosan nanoparticle coating, the mechanical properties of paper after artificial aging were evaluated using dry heat and hygrothermal accelerated aging methods. The SEM, EDX, and X-ray Photoelectron Spectroscopy (XPS) were used to analyze the interaction mechanism between chitosan and Shuxuan paper. The results show that the coated paper had superior durability with respect to pH, tensile strength, and folding endurance. There was a presence of protonated amines in the form of ammonium salts due to ionic bindings with free H+ in the acidified paper, and the remaining –NH2 could be used as a base reserve. Finally, the resulting coated papers displayed good antibacterial properties.

scholarly journals The adsorption behavior and mechanism investigation of Cr(VI) ions removal by poly(2-(dimethylamino)ethyl methacrylate)/poly(ethyleneimine) gels

2015 ◽  
Vol 80 (7) ◽  
pp. 889-902 ◽  
Author(s):  
Zhengbo Hou ◽  
Weixia Zhu ◽  
Hang Song ◽  
Pengfei Chen ◽  
Shun Yao
Keyword(s):  
Photoelectron Spectroscopy ◽  
Adsorption Process ◽  
Interaction Mechanism ◽  
Langmuir Model ◽  
Adsorption Behavior ◽  
Maximum Adsorption Capacity ◽  
X Ray ◽  
Ethyl Methacrylate ◽  
Pseudo Second Order ◽  
Scanning Electron

The composite hydrogels based on N,N?-dimethylamino ethyl methacrylate (DMAEMA) and polyethyleneimine (PEI) were prepared by amino radical polymerization and confirmed by Fourier Transform Infrared Spectra (FTIR) and elemental analysis. Then adsorption behavior and mechanism of Cr(VI) ions on the obtained materials were investigated with scanning electron microscope, Zeta potential and thermal gravity analysis, etc. The adsorption process was found to follow the pseudo-second order kinetics and Langmuir model, and the maximum adsorption capacity of Cr(VI) ions reached 122.8 mg g-1. X-ray photoelectron spectroscopy (XPS) and pH analysis revealed that the Cr(VI) ions were adsorbed into the gels through electrostatic interaction mechanism, and SO42- in the solution had a great effect on the adsorption process. In addition, high pH and ionic strength could reduce the uptakes of adsorbate, which could be used for desorption of Cr(VI) ions from the gels.

scholarly journals Palladium-doped hierarchical ZSM-5 for catalytic selective oxidation of allylic and benzylic alcohols

2021 ◽  
Vol 8 (10) ◽  
Author(s):  
Shengzhe Ding ◽  
Muhammad Ganesh ◽  
Yilai Jiao ◽  
Xiaoxia Ou ◽  
Mark A. Isaacs ◽  
...  
Keyword(s):  
Selective Oxidation ◽  
Active Site ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Hierarchical Zeolites ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Temperature Programmed ◽  
Alcohol Conversion

Hierarchical zeolites have the potential to provide a breakthrough in transport limitation, which hinders pristine microporous zeolites and thus may broaden their range of applications. We have explored the use of Pd-doped hierarchical ZSM-5 zeolites for aerobic selective oxidation (selox) of cinnamyl alcohol and benzyl alcohol to their corresponding aldehydes. Hierarchical ZSM-5 with differing acidity (H-form and Na-form) were employed and compared with two microporous ZSM-5 equivalents. Characterization of the four catalysts by X-ray diffraction, nitrogen porosimetry, NH 3 temperature-programmed desorption, CO chemisorption, high-resolution scanning transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy allowed investigation of their porosity, acidity, as well as Pd active sites. The incorporation of complementary mesoporosity, within the hierarchical zeolites, enhances both active site dispersion and PdO active site generation. Likewise, alcohol conversion was also improved with the presence of secondary mesoporosity, while strong Brønsted acidity, present solely within the H-form systems, negatively impacted overall selectivity through undesirable self-etherification. Therefore, tuning support porosity and acidity alongside active site dispersion is paramount for optimal aldehyde production.

Study on Effect Recyclability of Ru/Bentonite-TiO2 Catalysts in Glycerol Hydrogenolysis Reaction Using X-Ray Photoelectron Spectroscopy (XPS)

2012 ◽  
Vol 620 ◽  
pp. 289-294 ◽  
Author(s):  
Noraini Hamzah ◽  
Nor Asikin Mohamad Nordin ◽  
Wan Nor Roslam Wan Isahak ◽  
Mohamad Bin Kassim ◽  
Mohd Ambar Yarmo
Keyword(s):  
Active Site ◽  
Photoelectron Spectroscopy ◽  
Hydrogen Pressure ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Xps Analysis ◽  
X Ray ◽  
Glycerol Hydrogenolysis ◽  
Repeated Runs

Recyclability effect on catalytic performance of Ru supported on the mixture of bentonite-TiO2 for the hydrogenolysis of glycerol was investigated under reaction condition of 150°C, 2.0 MPa hydrogen pressure and 7 h reaction time. Interestingly, the recovered Ru/bentonite-TiO2 catalyst was found to be active in the repeated runs. The conversion of glycerol increased in the four successive reactions as follows: 61.3%, 65.6%, 68.1% and 75.3%. This suggested that a sort of metal activation affect such as in situ reduction occurred during the repeated reaction. In order to confirm in situ reduction had occurred during the repeated reaction, XPS analysis of used catalyst after each reaction were carried out to study the chemical state of Ru 3d species. Narrow scan of peak Ru 3d revealed that intensity of Ru 3d5/2 peak at BE 280.0 eV which is corresponding to Ru0 species increased until three cycle reaction. This result confirmed that in situ reduction had occurred during the repeated reaction and this made the activities of the catalyst increased upon recycling due to the availability of more metallic Ru on the surface of the catalyst. This study also shows that conversion of glycerol increased linearly with the percentage atomic ratio of Ru metal active site available on the surface of catalyst.

scholarly journals Effect of Al (III) Ions on the Separation of Cassiterite and Clinochlore Through Reverse Flotation

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 347 ◽  
Author(s):  
Yumeng Chen ◽  
Xiong Tong ◽  
Dongxia Feng ◽  
Xian Xie
Keyword(s):  
Contact Angle ◽  
Photoelectron Spectroscopy ◽  
Interaction Mechanism ◽  
Reverse Flotation ◽  
X Ray ◽  
Angle Measurements ◽  
Mineral Flotation ◽  
Contact Angle Measurements ◽  
Flotation Performance ◽  
Hydrophobic Clay

Most hydrophobic clay minerals, such as clinochlore, are known to cause problems in the recovery of cassiterite. In this study, a new reagent scheme, i.e., sodium oleate (NaOL) as a collector and Al (III) ions as a depressant, for reverse flotation separation of cassiterite and clinochlore was investigated. The flotation performance and interaction mechanism were studied by microflotation tests, adsorption tests, contact angle measurements, and X-ray photoelectron spectroscopy (XPS) analysis. Results of single mineral flotation experiments showed that NaOL had a different flotation performance on cassiterite and clinochlore, and the addition of Al (III) ions could selectively inhibit the floatability of cassiterite. Reverse flotation tests performed on mixed minerals indicated that the separation of cassiterite and clinochlore could be achieved in the presence of NaOL and Al (III) ions. Adsorption experiments demonstrated that Al (III) ions hindered the adsorption of NaOL on cassiterite surfaces but exerted little influence on the adsorption of NaOL on clinochlore surfaces. Results of contact angle measurements indicated that Al (III) ions could impede the hydrophobization process of cassiterite in NaOL solution. XPS results showed that aluminum species were adsorbed onto the cassiterite surfaces through the interaction with O sites.

scholarly journals Efficient Removal of Hexavalent Chromium from an Aquatic System Using Nanoscale Zero-Valent Iron Supported by Ramie Biochar

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2698
Author(s):  
Xiangpeng Tan ◽  
Muhammad Shaaban ◽  
Jianwei Yang ◽  
Yajun Cai ◽  
Buyun Wang ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Photoelectron Spectroscopy ◽  
Interaction Mechanism ◽  
Reduction Reaction ◽  
Zero Valent Iron ◽  
Adsorption Activity ◽  
X Ray ◽  
Nano Zero Valent Iron ◽  
Multiple Interaction ◽  
Co Precipitation

In this study, ramie biochar (RBC) was used to activate nano zero-valent iron (nZVI) to enhance hexavalent chromium (Cr(VI)) removal. The best results were obtained at a pyrolysis temperature of 600 °C, a biochar particle size of < 150 μm, and an iron to carbon ratio = 1:1. Under the optimal conditions, the removal of Cr(VI) by RBC600-nZVI (98.69%) was much greater than that of RBC600 (12.42%) and nZVI (58.26%). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) revealed that the reaction mechanism at the Fe and Cr interface was a multiple interaction mechanism with reduction dominated, adsorption, and co-precipitation simultaneously. The enhanced performance of RBC600-nZVI resulted from the effective dispersion of nZVI on the surface of RBC600, therefore increasing the adsorption activity sites. At the same time, RBC600 and nZVI exerted a synergistic influence on the composite structure, which jointly promoted the reduction reaction of Cr(VI) and removed more Cr(VI). This study shows that RBC-nZVI is a potentially valuable remediation material that not only provides a new idea for the utilization of ramie waste, but also effectively overcomes the limitations of nZVI, thus, achieving efficient and rapid remediation of Cr(VI).

scholarly journals Active Site of O2 and Its Improvement Mechanism over Ce-Ti Catalyst for NH3-SCR Reaction

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 336 ◽  
Author(s):  
Dong Jiang ◽  
Shule Zhang ◽  
Yiqing Zeng ◽  
Pengfei Wang ◽  
Qin Zhong
Keyword(s):  
Active Site ◽  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Catalytic Reduction ◽  
Supported Catalyst ◽  
Temperature Programmed Desorption ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Adsorption Sites ◽  
Temperature Programmed

The current study on Ce-Ti catalyst was mainly focused on the function of NH3 and NO adsorption sites. In our study, by comparing Ce-Ti (doped catalyst) to Ce/Ti (supported catalyst), the active site of O2 and its improvement mechanism over Ce-Ti catalyst for NH3-Selective catalytic reduction (SCR) reactions were investigated. For Ce-Ti catalyst, a cerium atom was confirmed entering a TiO2 crystal lattice by X-ray diffraction (XRD) and Raman; the structure of Ce-□-Ti (□ represents oxygen vacancy) in Ce-Ti catalyst was confirmed by X-ray photoelectron spectroscopy (XPS) and Photoluminescence spectra (PL spectra). The nature of this structure was characterized by electron paramagnetic resonance (EPR), Ammonia temperature-programmed desorption (NH3-TPD), hydrogen temperature-programmed reduction (H2-TPR), Nitric oxide temperature-programmed desorption (NO-TPD) and In situ DRIFT. The results indicated that oxygen vacancies had a promotive effect on the adsorption and activation of oxygen, and oxygen was converted to superoxide ions in large quantities. Also, because of adsorption and activation of NO and NH3, electrons were transferred to adsorbed oxygen via oxygen vacancies, which also promoted the formation of superoxide ions. We expected that our study could promote understanding of the active site of O2 and its improvement mechanism for doped catalyst.

scholarly journals Combined DFT and XPS Investigation of Cysteine Adsorption on the Pyrite (1 0 0) Surface

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 366 ◽  
Author(s):  
Xingfu Zheng ◽  
Xuan Pan ◽  
Zhenyuan Nie ◽  
Yi Yang ◽  
Lizhu Liu ◽  
...  
Keyword(s):  
First Principles ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Interaction Mechanism ◽  
Energy Calculation ◽  
Ionic Bond ◽  
Frontier Orbitals ◽  
Functional Theory ◽  
Xps Spectra ◽  
X Ray

The adsorption of cysteine on the pyrite (1 0 0) surface was evaluated by using first-principles-based density functional theory (DFT) and X-ray photoelectron spectroscopy (XPS) measurements. The frontier orbitals analyses indicate that the interaction of cysteine and pyrite mainly occurs between HOMO of cysteine and LUMO of pyrite. The adsorption energy calculation shows that the configuration of the -OH of -COOH adsorbed on the Fe site is the thermodynamically preferred adsorption configuration, and it is the strongest ionic bond according to the Mulliken bond populations. As for Fe site mode, the electrons are found transferred from cysteine to Fe of pyrite (1 0 0) surface, while there is little or no electron transfer for S site mode. Projected density of states (PDOS) is analyzed further in order to clarify the interaction mechanism between cysteine and the pyrite (1 0 0) surface. After that, the presence of cysteine adsorption on the pyrite (1 0 0) surface is indicated by the qualitative results of the XPS spectra. This study provides an alternative way to enhance the knowledge of microbe–mineral interactions and find a route to improve the rate of bioleaching.

Sign in / Sign up

Export Citation Format

Share Document