NH4Br-Modified Biomass Char for Mercury Removal in a Simulated Oxy-fuel Atmosphere: Mechanism Analysis by X-ray Photoelectron Spectroscopy

In this work, the high crystalline copper oxide (CuO) nanoparticles were fabricated by a hydrothermal method, and their structural properties were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The sensing results show that CuO nanoparticles exhibit enhanced sensitivity and good selectivity for hydrogen sulfide (H2S) gas at a low temperature. There are two working mechanisms involved in the H2S sensing based on CuO nanoparticle sensors. They are the H2S oxidation mechanism and the copper sulphide (CuS) formation mechanism, respectively. The two sensing mechanisms collectively enhance the sensor’s response in the H2S sensing process. The Cu–S bonding is stable and cannot break spontaneously at a low temperature. Therefore, the CuS formation inhibits the sensor’s recovery process. Such inhibition gradually enhances as the gas concentration increases from 0.2 ppm to 5 ppm, and it becomes weaker as the operating temperature rises from 40 °C to 250 °C. The XPS results confirmed the CuS formation phenomenon, and the micro Raman spectra demonstrated that the formation of CuS bonding and its decomposition can be effectively triggered by a thermal effect. Gas-sensing mechanism analysis supplied abundant cognition for the H2S sensing phenomena based on CuO materials.

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Removal of trace mercury (II) from aqueous solution by in situ MnOx combined with poly-aluminum chloride

Journal of Water and Health ◽

10.2166/wh.2014.156 ◽

2014 ◽

Vol 13 (2) ◽

pp. 383-393 ◽

Cited By ~ 2

Author(s):

Xixin Lu ◽

Xiaoliu Huangfu ◽

Xiang Zhang ◽

Yaan Wang ◽

Jun Ma

Keyword(s):

Water Quality ◽

Aqueous Solution ◽

Mercury Concentration ◽

Aluminum Chloride ◽

Photoelectron Spectroscopy ◽

Active Sites ◽

Mercury Removal ◽

Experimental Conditions ◽

X Ray

Removal of trace mercury from aqueous solution by Mn (hydr)oxides formed in situ during coagulation with poly-aluminum chloride (PAC) (in situ MnOx combined with PAC) was investigated. The efficiency of trace mercury removal was evaluated under the experimental conditions of reaction time, Mn dosage, pH, and temperature. In addition, the ionic strength and the initial mercury concentration were examined to evaluate trace mercury removal for different water qualities. The results clearly demonstrated that in situ MnOx combined with PAC was effective for trace mercury removal from aqueous solution. A mercury removal ratio of 9.7 μg Hg/mg Mn was obtained at pH 3. Furthermore, at an initial mercury concentration of 30 μg/L and pH levels of both 3 and 5, a Mn dosage of 4 mg/L was able to lower the mercury concentration to meet the standards for drinking water quality at less than 1 μg/L. Analysis by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy suggests that the hydroxyls on the surface of Mn (hydr)oxides are the active sites for adsorption of trace mercury from aqueous solution.

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Passivation mechanism analysis of sulfur-passivated InGaP surfaces using x-ray photoelectron spectroscopy

Journal of Applied Physics ◽

10.1063/1.373057 ◽

2000 ◽

Vol 87 (9) ◽

pp. 4230-4233 ◽

Cited By ~ 23

Author(s):

Chang-Da Tsai ◽

Ching-Ting Lee

Keyword(s):

Photoelectron Spectroscopy ◽

Mechanism Analysis ◽

X Ray

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Mercury Removal from Aqueous Solutions Using Modified Pyrite: A Column Experiment

Minerals ◽

10.3390/min10010043 ◽

2019 ◽

Vol 10 (1) ◽

pp. 43 ◽

Cited By ~ 1

Author(s):

Yucheng Zhu ◽

Shuchuan Peng ◽

Ping Lu ◽

Tianhu Chen ◽

Yan Yang

Keyword(s):

Electron Microscopy ◽

Aqueous Solutions ◽

Field Emission ◽

Photoelectron Spectroscopy ◽

Fixed Bed ◽

Column Experiment ◽

Mercury Removal ◽

Emission Standard ◽

X Ray ◽

Natural Pyrite

Modified pyrite (MPy), which was obtained from calcination in an N2 atmosphere, was used as a sorbent for removing Hg(II) from aqueous solutions. Fixed-bed column experiments were conducted to determine the Hg(II) removal ability of MPy from aqueous solutions. MPy was found to be much better than natural pyrite for mercury removal. The concentration of Hg(II) in effluents was much lower than that of the emission standard used for Hg wastewater in China (0.05 mg/L), and the removal efficiency of Hg(II) was greater than 99% before breakthrough. When the capacity was 3274 times the column bed volume (1 bed volume = 25.12 cm3), the column breakthrough and the sorption amount of Hg(II) were 54.44 mg/g. The Hg(II) content in the used MPy sorbent was up to 24.79%. The mechanism was analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), field emission transmission electron microscopy (FE-TEM), and X-ray Photoelectron Spectroscopy (XPS). The main mechanism of Hg(II) removal by MPy was the chemical reactions between mercury ions and mineral fillers, and HgS precipitated on the surface of MPy to remove Hg(II). The reaction was also accompanied by surface complexation and adsorption. The results of this work show that MPy can be used as a sorbent for continuous Hg(II) removal.

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A Novel Absorbent of Nano-Fe Loaded Biomass Char and Its Enhanced Adsorption Capacity for Phosphate in Water

Journal of Chemistry ◽

10.1155/2013/649868 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 4

Author(s):

Hongguang Zhou ◽

Zhenmao Jiang ◽

Shiqiang Wei

Keyword(s):

Aqueous Solutions ◽

Adsorption Capacity ◽

Photoelectron Spectroscopy ◽

Freundlich Isotherm ◽

Phosphate Adsorption ◽

Porous Structures ◽

Sem Images ◽

X Ray ◽

Intraparticle Diffusion Model ◽

Biomass Char

A novel composite adsorbent of Fe loaded biomass char (Fe-BC) was fabricated to treat phosphorus in water. Fe-BC was prepared by a procedure including metal complex anion incorporation and precipitation with the pyrolysis char of corn straw as supporting material. The abundant porous structures of the as-prepared sample can be easily observed from its scanning electron microscopy (SEM) images. Observations by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses show that inorganic nanoiron oxides deposited in the composite could be amorphous hydrous iron oxideα-FeOOH. Adsorption of phosphate onto the Fe-BC composite and its precursor (BC) from aqueous solutions were investigated and discussed. The equilibrium adsorption data of phosphate was described by Langmuir and Freundlich models, and Langmuir isotherm was found to be better fitted than Freundlich isotherm. The maximum phosphate adsorption capacity for phosphate of Fe-BC was as high as 35.43 mg/g, approximately 2.3 times of BC at 25°C. The adsorption kinetics data were better fitted by pseudo-second-order model and intraparticle diffusion model, indicating that the adsorption process was complex. The Fe-BC composite has been proved as an effective adsorbent of phosphate from aqueous solutions owing to its unique porous structures and the greater Lewis basicity of theα-FeOOH.

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Adsorption of cupric, cadmium and cobalt ions from the aqueous stream using the composite of iron(II,III) oxide and zeolitic imidazole framework-8

Water Science & Technology ◽

10.2166/wst.2021.452 ◽

2021 ◽

Author(s):

Pushpmala Kuwer ◽

Anshul Yadav ◽

Pawan Kumar Labhasetwar

Keyword(s):

Thermal Stability ◽

Toxic Metals ◽

Photoelectron Spectroscopy ◽

Structural Integrity ◽

Toxic Metal ◽

Mechanism Analysis ◽

Potentially Toxic Metals ◽

Cobalt Ions ◽

X Ray ◽

Adsorption Processes

Abstract In recent research, the composite of Fe3O4 and metal-organic frameworks have shown great potential in removing potentially toxic metals from water. We conducted the adsorption studies of potentially toxic metal ions (Cu2+, Co2+ and Cd2+) using the composite of Fe3O4 and zeolitic imidazole framework-8 (Fe3O4@ZIF-8) for the first time. The solvothermal technique was used to synthesize the Fe3O4. The magnetic ZIF-8 offers high thermal stability, greater adsorption surface, good removability, and high chemical and thermal stability. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the synthesized samples. The SEM and XRD results revealed the high purity and structural integrity of ZIF-8 crystallites. To remove potentially toxic metals (Cu2+, Co2+ and Cd2+), the influence of adsorbent dosage, contact time, pH, and adsorbate concentration on the adsorption performance of Fe3O4@ZIF-8 was investigated. Langmuir isotherm accurately represented the adsorption processes, with absorption magnitudes of Fe3O4@ZIF-8 determined to be 46.82 mg g−1, 71.29 mg g−1 and 54.49 mg g−1 for Cu2+, Co2+ and Cd2+, respectively. According to the adsorption mechanism analysis, the primary Cu2+, Co2+ and Cd2+ removal methods of Fe3O4@ZIF-8 were ion exchange and coordination bonds. The uptake capacity of Cu2+, Co2+ and Cd2+ solution by Fe3O4@ZIF-8 were not significantly affected by the presence of counter ions. The material exhibited superior regenerative properties for Cu2+, Co2+ and Cd2+ ions from the water up to three cycles. This study concluded that the Fe3O4@ZIF-8 could be a viable candidate for eliminating potentially toxic metals (Cu2+, Co2+ and Cd2+).

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