pH-Induced Protonation of Lysine in Aqueous Solution Causes Chemical Shifts in X-ray Photoelectron Spectroscopy

2007 ◽  
Vol 129 (45) ◽  
pp. 14068-14073 ◽  
Author(s):  
Dirk Nolting ◽  
Emad F. Aziz ◽  
Niklas Ottosson ◽  
Manfred Faubel ◽  
Ingolf V. Hertel ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Chemical Shifts ◽  
X Ray

scholarly journals XPS Investigations on Solid and Vacuum Deposited, Oxidized and Non-oxidized Palladium

1995 ◽  
Vol 50 (4-5) ◽  
pp. 381-387 ◽  
Author(s):  
Jürgen Kintrup ◽  
Harald Züchner
Keyword(s):  
Chemical Shift ◽  
Curve Fitting ◽  
Photoelectron Spectroscopy ◽  
Chemical Shifts ◽  
Atmospheric Oxygen ◽  
Hydrogen Permeability ◽  
Photoelectric Effect ◽  
High Accuracy ◽  
X Ray ◽  
Charging Effect

Abstract X-ray photoelectron spectroscopy (XPS) has been carried out to study the reaction of differently prepared palladium samples (solid and film Pd) with atmospheric oxygen. A careful curve fitting of the measured Pd-3d5/2 peak allows to separate the Pd-3d5/2 peak for Pd in surface PdO from the dominant Pd-3d5/2 peak of the non-oxidized bulk palladium and to determine the chemical shift of the "oxidized" Pa line with high accuracy. Differences in the chemical shifts for the surface PdO on solid and film palladium are explained by a different charging caused by the photoelectric effect in XPS measurements. The smaller charging effect observed for film palladium as compared to solid palladium indicates a stronger oxygen bonding to the (rougher) film palladium. The strong Pd-O bonding seems to be an essential reason for the reduced hydrogen-permeability of film palladium compared to solid palladium

scholarly journals Succinic acid in aqueous solution: connecting microscopic surface composition and macroscopic surface tension

2014 ◽  
Vol 16 (39) ◽  
pp. 21486-21495 ◽  
Author(s):  
Josephina Werner ◽  
Jan Julin ◽  
Maryam Dalirian ◽  
Nønne L. Prisle ◽  
Gunnar Öhrwall ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Surface Tension ◽  
Succinic Acid ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Md Simulations ◽  
Vapor Interface ◽  
X Ray ◽  
Ph Values ◽  
Microscopic Surface

The water–vapor interface of aqueous solutions of succinic acid, where pH values and bulk concentrations were varied, has been studied using surface sensitive X-ray photoelectron spectroscopy (XPS) and molecular dynamics (MD) simulations.

scholarly journals Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
D. Mayer ◽  
F. Lever ◽  
D. Picconi ◽  
J. Metje ◽  
S. Alisauskas ◽  
...  
Keyword(s):  
Excited State ◽  
Chemical Shift ◽  
Photoelectron Spectroscopy ◽  
Chemical Shifts ◽  
Excited Molecule ◽  
Charge Motion ◽  
Core Electron ◽  
Xps Spectra ◽  
X Ray ◽  
State Chemical

AbstractThe conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220–250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states.

scholarly journals Effect of synthesis conditions  on  methylene blue adsorption capacity of electrochemically preparated graphene

2020 ◽  
Vol 9 (3) ◽  
pp. 9-14
Author(s):  
Hao Pham Van ◽  
Linh Ha Xuan ◽  
Oanh Phung Thi ◽  
Hong Phan Ngoc ◽  
Huy Nguyen Nhat ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Adsorption Capacity ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Graphene Nanosheets ◽  
Electrochemical Exfoliation ◽  
X Ray ◽  
Synthesis Conditions ◽  
Mb Adsorption

This report presents the effect of synthesis conditions on the synthesis of graphene nanosheets via electrochemical exfoliation method for adsorbing methylene blue from aqueous solution. Oxygen-containing functional groups and defects in the material were characterized by Raman and X-ray photoelectron spectroscopy (XPS). As a result, by using voltage of 15 V, (NH4)2SO4 (5%, 250 mL) and KOH (7.5%, 250 mL), the obtained material showed the highest MB adsorption capacity due to the high densities of oxygen-containing groups and defects comparison to other conditions.

scholarly journals Synthesis of Nanoscale Zerovalent Iron (nZVI) Supported on Biochar for Chromium Remediation from Aqueous Solution and Soil

2019 ◽  
Vol 16 (22) ◽  
pp. 4430 ◽  
Author(s):  
Haixia Wang ◽  
Mingliang Zhang ◽  
Hongyi Li
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Zero Valent Iron ◽  
Zerovalent Iron ◽  
X Ray ◽  
Nanoscale Zerovalent Iron ◽  
Before And After ◽  
Pseudo Second Order ◽  
Xrd Patterns ◽  
Co Precipitation

Maize straw biochar-supported nanoscale zero-valent iron composite (MSB-nZVI) was prepared for efficient chromium (Cr) removal through alleviating the aggregation of zero-valent iron particles. The removal mechanism of MSB-nZVI was investigated by scanning electron microscopy with energy dispersive X-ray (SEM-EDX), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). Cr(VI) removal from aqueous solution by MSB-nZVI was greatly affected by pH and initial concentration. The removal efficiency of Cr(VI) decreased with increasing pH, and the removal kinetics followed the pseudo-second-order model. XRD patterns of MSB-nZVI before and after reaction showed that reduction and precipitation/co-precipitation (FeCr2O4, Fe3O4, Fe2O3) occurred with the conversion of Cr(VI) to Cr(III) and Fe(0) to Fe(II)/Fe(III). The produced precipitation/co-precipitation could be deposited on the MSB surface rather than being only coated on the surface of nZVI particles, which can alleviate passivation of nZVI. For remediation of Cr(VI)-contaminated saline–alkali soil (pH 8.6–9.0, Cr 341 mg/kg), the released amount of Cr(VI) was 70.7 mg/kg, while it sharply decreased to 0.6–1.7 mg/kg at pH 4.0–8.0, indicating that the saline–alkali environment inhibited the remediation efficiency. These results show that MSB-nZVI can be used as an effective material for Cr(VI) removal from aqueous solution and contaminated soil.

Preparation and Characterization of Carbon Nanotubes/Al2O3 Inorganic Hybrid Material - A Bio-Inspired Poly(Dopamine) Approach

2018 ◽  
Vol 54 ◽  
pp. 127-135
Author(s):  
Wen Zhao ◽  
Wen Cai Wang ◽  
Yong Lai Lu ◽  
Li Qun Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Oxidative Polymerization ◽  
The Self ◽  
Liquid Phase Deposition ◽  
X Ray ◽  
Transmission Electron ◽  
Cnts Surface

Carbon nanotubes/alumina (CNTs/Al2O3) nanocomposites were prepared by the poly (dopamine) assisted chemical liquid phase deposition (CLPD). The poly (dopamine) layers were firstly coated on the CNTs surface uniformly by the self-oxidative polymerization of dopamine in mild aqueous solution and then the Al2O3 nanoparticles formed on the poly (dopamine) coated CNTs surface by the CLPD. The hydrophilic poly (dopamine) layers on the CNTs surface can improve the dispersion of CNTs in aqueous solution. Moreover, it can be used as a key linker between the CNTs and Al2O3 because of the nitrogen-containing group in poly (dopamine) could coordinate with Al3+ ions. The as-prepared poly (dopamine) coated CNTs and CNTs/Al2O3 nanohybrids were characterized by X-ray photoelectron spectroscopy (XPS), X-radial diffractometer (XRD) and high resolution transmission electron microscopy (HRTEM). These results showed that the poly (dopamine) layers were coated on the surface of CNTs uniformly, and the Al2O3 nanoparticles embellished with the poly (dopamine) coated CNTs surface. Compared with pristine NR composites, the thermal conductivity of the as-prepared NR/CNTs@Al2O3 composites increased 17%.

scholarly journals SBA-16 Cage-Like Porous Material Modified with APTES as an Adsorbent for Pb2+ Ions Removal from Aqueous Solution

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 927 ◽  
Author(s):  
Viviana Palos-Barba ◽  
Abigail Moreno-Martell ◽  
Verónica Hernández-Morales ◽  
Carmen L. Peza-Ledesma ◽  
Eric M. Rivera-Muñoz ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Contact Time ◽  
Diffuse Reflectance Spectroscopy ◽  
Cell Structure ◽  
Textural Properties ◽  
Batch Adsorption ◽  
X Ray ◽  
Ion Removal ◽  
Transmission Electron

Tridimensional cubic mesoporous silica, SBA-16, functionalized with aminopropyl groups, were employed as adsorbents for Pb2+ ion removal from aqueous solution. The adsorption capacity was investigated for the effect of pH, contact time, temperature, and concentration of 3-aminopropyltriethoxysilane (APTES) employed for adsorbent functionalization. The textural properties and morphology of the adsorbents were evaluated by N2 physisorption, small-angle X-ray diffraction (XRD), diffuse reflectance spectroscopy (UV-vis), and transmission electron microscopy (TEM). The functionalization of the SBA-16 was evaluated by elemental analysis (N), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Batch adsorption studies show that the total Pb2+ ions removal was archived on adsorbent having an optimized amount of aminopropyl groups (2N-SBA-16). The maximum of Pb2+ ions removal occurred at optimized adsorption conditions: pH = 5–6, contact time 40 min, and at a low initial lead concentration in solution (200 mg L−1). Under the same adsorption conditions, the amino-functionalized SBA-16 with cubic 3D unit cell structure exhibited higher adsorption capability than its SBA-15 counterpart with uniform mesoporous channels.

scholarly journals Removal Efficiency and Mechanism of Cr(VI) from Aqueous Solution by Maize Straw Biochars Derived at Different Pyrolysis Temperatures

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 781 ◽  
Author(s):  
Wang ◽  
Zhang ◽  
Lv
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
X Ray ◽  
Removal Capacity ◽  
Maize Straw ◽  
Efficient Adsorbent ◽  
Positively Charged ◽  
Maximum Removal

The removal efficiency and mechanism of Cr(VI) removal from aqueous solution on semi-decomposed maize straw biochars pyrolyzed at 300 to 600 °C were investigated. The removal of Cr(VI) by the biochars decreased with pyrolysis temperature increasing from 300 to 600 °C, and the maximum removal capacity of Cr(VI) for maize straw biochar pyrolyzed at 300 °C was 91 mg/g at pH 2.0. The percentage removal of Cr(VI) rapidly decreased with pH increasing from 2.0 to 8.0, with the maximum (>99.9%) at pH 2.0. The variation of Cr(VI) and Cr(III) concentrations in the solution after reaction showed that Cr(VI) concentration decreased while Cr(III) increased and the equilibrium was reached after 48 h, while the redox potential after reaction decreased due to Cr(VI) reduction. X-ray photoelectron spectroscopy (XPS) semi-quantitative analysis showed that Cr(III) accounted for 75.7% of the total Cr bound to maize straw biochar, which indicated reductive adsorption was responsible for Cr(VI) removal by the biochars. Cr(VI) was firstly adsorbed onto the positively charged biochar surface and reduced to Cr(III) by electrons provided by oxygen-containing functional groups (e.g., C=O), and subsequently part of the converted Cr(III) remained on the biochar surface and the rest released into solution. Fourier transform infrared (FTIR) data indicated the participation of C=O, Si–O, –CH2 and –CH3 groups in Cr(VI) removal by the biochars. This study showed that maize straw biochar pyrolyzed at 300 °C for 2 h was one low-cost and efficient adsorbent for Cr(VI) removal from aqueous solution.

Sign in / Sign up

Export Citation Format

Share Document