Summary Abstract: Nonlinear least‐squares fitting employing fast Fourier transform background generation for the x‐ray photoelectron spectroscopy analysis of iron oxidation

1988 ◽  
Vol 6 (3) ◽  
pp. 1044-1045 ◽  
Author(s):  
B. L. Maschhoff ◽  
N. R. Armstrong
Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 599
Author(s):  
Yanping Niu ◽  
Ya Li ◽  
Haoran Sun ◽  
Chuanyao Sun ◽  
Wanzhong Yin ◽  
...  

Ferric ions produced during grinding influence the flotation separation between kyanite and quartz adversely. In this study, citric acid was used as a regulator to eliminate the effect of ferric ions on the separation of kyanite from quartz with sodium oleate (NaOL) as a collector. The microflotation test results indicated that the quartz was selectively activated by FeCl3 and maintained significant quartz recovery. However, the citric acid could selectively eliminate the effect of ferric ions on the quartz and minimally influenced the kyanite. Contact angle tests demonstrated that FeCl3 significantly increased the interaction between NaOL and quartz, resulting in the high hydrophobicity of quartz, and the addition of citric acid made the quartz surface hydrophilic again but slightly influenced the kyanite. Fourier-transform infrared spectroscopy showed that FeCl3 facilitated NaOL adsorption onto the quartz surface, and the addition of citric acid eliminated the activation of FeCl3 on the quartz, resulting in the nonadsorption of NaOL onto the quartz surface. However, the FeCl3 and citric acid exhibited a negligible effect on NaOL adsorption onto the kyanite surface. X-ray photoelectron spectroscopy analysis indicated that the citric acid eliminated FeCl3 activation on the quartz.


Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3588
Author(s):  
Jiayi Chen ◽  
Yansong Liu ◽  
Jiayue Zhang ◽  
Yuanlin Ren ◽  
Xiaohui Liu

Lyocell fabrics are widely applied in textiles, however, its high flammability increases the risk of fire. Therefore, to resolve the issue, a novel biomass-based flame retardant with phosphorus and nitrogen elements was designed and synthesized by the reaction of arginine with phosphoric acid and urea. It was then grafted onto the lyocell fabric by a dip-dry-cure technique to prepare durable flame-retardant lyocell fabric (FR-lyocell). X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated that the flame retardant was successfully introduced into the lyocell sample. Thermogravimetric (TG) and Raman analyses confirmed that the modified lyocell fabric featured excellent thermal stability and significantly increased char residue. Vertical combustion results indicated that FR-lyocell before and after washing formed a complete and dense char layer. Thermogravimetric Fourier-transform infrared (TG-FTIR) analysis suggested that incombustible substances (such as H2O and CO2) were produced and played a significant fire retarding role in the gas phase. The cone calorimeter test corroborated that the peak of heat release rate (PHRR) and total heat release (THR) declined by 89.4% and 56.4%, respectively. These results indicated that the flame retardancy of the lyocell fabric was observably ameliorated.


2016 ◽  
Vol 20 (3) ◽  
pp. 967-972 ◽  
Author(s):  
Peng Liu ◽  
Chun-Hui He ◽  
Fujuan Liu ◽  
Lan Xu ◽  
Yuqin Wan ◽  
...  

In this work, ?-Fe2O3 nanobulk with high aspect ratio were successfully prepared via a facile bubble electrospinning technique using polyvinylidene fluoride and iron chloride hexahydrate (FeCl3?6H2O) as ?-Fe2O3 precursor followed by annealing in air at 600?C. The products were characterized with field emission scanning electron microscope, Fourier transform infrared, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The results showed that ?-Fe2O3 nanobulk has a hierarchical heterostructure which has an extremely broad application prospect in many areas.


2017 ◽  
Vol 31 (5) ◽  
pp. 657-667 ◽  
Author(s):  
S Varnagiris ◽  
S Tuckute ◽  
M Lelis ◽  
D Milcius

Currently, polymeric insulation materials are widely used for energy saving in buildings. Despite of all benefits, these materials are generally sensitive to heat and highly flammable. This work discusses possibility to improve heat resistance of expanded polystyrene (EPS) foam using thin silicon dioxide (SiO2) films deposited by magnetron sputtering technique. In order to increase surface energy and adherence of SiO2 thin films to substrate EPS was plasma pretreated before films’ depositions using pulsed DC plasma generator for 40 s in argon gas. SiO2 formation was done in reactive argon and oxygen gas atmosphere. Laboratory made equipment was used for flame torch–induced heat resistance experiments. Results showed that silicon oxide films remains stable during heat resistance experiments up to 5 s and fully protects polystyrene (PS) substrate. Films are relatively stable for 30 s and 60 s and partially protect PS from melting and ignition. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy analysis confirmed that SiO2 layer, which is distributed uniformly on the EPS surface, could work as a good heat resistant material.


Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1377
Author(s):  
Yuki Semoto ◽  
Gde Pandhe Wisnu Suyantara ◽  
Hajime Miki ◽  
Keiko Sasaki ◽  
Tsuyoshi Hirajima ◽  
...  

Sodium metabisulfite (MBS) was used in this study for selective flotation of chalcopyrite and molybdenite. Microflotation tests of single and mixed minerals were performed to assess the floatability of chalcopyrite and molybdenite. The results of microflotation of single minerals showed that MBS treatment significantly depressed the floatability of chalcopyrite and slightly reduced the floatability of molybdenite. The results of microflotation of mixed minerals demonstrated that the MBS treatment could be used as a selective chalcopyrite depressant in the selective flotation of chalcopyrite and molybdenite. Furthermore, the addition of diesel oil or kerosene could significantly improve the separation efficiency of selective flotation of chalcopyrite and molybdenite using MBS treatment. A mechanism based on X-ray photoelectron spectroscopy analysis results is proposed in this study to explain the selective depressing effect of MBS on the flotation of chalcopyrite and molybdenite.


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