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

Abstract

Abstract: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.

Quaternization of Composite Algal/PEI Beads for Enhanced Uranium Sorption—Application to Ore Acidic Leachate

“…As reported above, the appearance of S 2p signal on metal-loaded sorbent at 167.25 eV (which is assigned to sulfate groups [59][60][61][62]) means that sulfate (as well as HSO4 − ) probably binds onto the quaternary ammonium groups at the surface of the sorbent at pH 4 (see Scheme High-resolution spectra (HRES) (and the assignments of deconvoluted peaks) for selected signals are also shown in Tables S2 and S3. These data were previously discussed [41].…”

Simultaneous Removal of Antibiotic Resistant Bacteria, Antibiotic Resistance Genes, and Micropollutants by FeS2@GO-Based Heterogeneous Photo-Fenton Process

“…The hydroxyl (HO) and water (H 2 O) peaks appear at 531.0 and 533.5 eV, respectively, which correspond to the oxygen functional groups (Figure c) . The bimodal features of the S 2p spectrum (S 2p 3/2 and S 2p 1/2 ) were found at 162.44 and 163.57 eV, respectively (Figure d), with a splitting of 1.13 eV, and are attributed to disulfide (S 2 2– ) and monosulfide (S 2– ) dimer. , The peaks around 707.1 and 720.0 eV in the Fe 2p spectrum are assigned to Fe 2p 3/2 and 2p 1/2 , respectively, and correspond to Fe 2+ -S (Figure e). The peak around 709.5 eV corresponds to Fe 2+ -O. , A new peak around 711.8 eV is also observed with the previous three peaks in GO-coated FeS 2 (Figure e).…”

“…14 The bimodal features of the S 2p spectrum (S 2p 3/2 and S 2p 1/2 ) were found at 162.44 and 163.57 eV, respectively (Figure 3d), with a splitting of 1.13 eV, and are attributed to disulfide (S 2 2− ) and monosulfide (S 2− ) dimer. 25,26 The peaks around 707.1 and 720.0 eV in the Fe 2p spectrum are assigned to Fe 2p 3/2 and 2p 1/2 , respectively, and correspond to Fe 2+ -S (Figure 3e). The peak around 709.5 eV corresponds to Fe 2+ -O.…”

Comparative Study on Surface Structure, Electronic Properties of Sulfide and Oxide Minerals: A First-Principles Perspective

“…It is not a new topic that different surface properties lead to significant differences in flotation behaviors. The investigations about surface structure and properties of sulfide and oxide minerals are not rare, and corresponding papers include ultraviolet photoelectron spectroscopy (UPS) [3,4], Raman spectroscopy [5], scanning tunneling microscopy (STM) [3,6], time of flight secondary ion mass spectrometry, (ToF-SIMS) [6,7], x-ray photoelectron spectroscopy (XPS) [8][9][10][11], DFT studies [8,9,[12][13][14], etc. Recently, reports with density functional theory method (DFT) triggered intense research in this area.…”