scholarly journals Elemental Mercury Adsorption by Cupric Chloride-Modified Mesoporous Carbon Aerogel

2018 ◽  
Vol 2 (4) ◽  
pp. 66 ◽  
Author(s):  
Dongjing Liu ◽  
Cheng Lu ◽  
Jiang Wu
Keyword(s):  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Mesoporous Carbon ◽  
Copper Chloride ◽  
Elemental Mercury ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
Mercury Adsorption ◽  
X Ray ◽  
Good Ability

Mesoporous carbon aerogels (MCA) synthesized via aqueous polymerization of resorcinol and formaldehyde were modified by copper chloride and applied for adsorption removal of elemental mercury (Hg0) at a low temperature. The sorbents were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, and X-ray photoelectron spectroscopy (XPS) techniques. The results show that CuCl2-modified MCA exhibited good ability for Hg0 adsorption in the 40–160 °C temperature range, with Hg0 removal efficiency all above 95.0%. The Hg0 removal efficiency first increased and then decreased with the elevation of reaction temperature. It performed optimally at 80 °C with the highest Hg0 removal efficiency of 98.7%. XPS results indicate that covalent chlorines (C-Cl groups) play an important role in elemental mercury adsorption process. Hg0 is firstly captured in the form of oxidized mercury (Hg2+) and then reacts with C-Cl groups to form HgCl2.

scholarly journals Nitrogen-Doped Carbon Aerogels Derived from Starch Biomass with Improved Electrochemical Properties for Li-Ion Batteries

2021 ◽  
Vol 22 (18) ◽  
pp. 9918
Author(s):  
Marcelina Kubicka ◽  
Monika Bakierska ◽  
Krystian Chudzik ◽  
Michał Świętosławski ◽  
Marcin Molenda
Keyword(s):  
Electrochemical Properties ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Potato Starch ◽  
Specific Capacity ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
Modern World ◽  
X Ray ◽  
Li Ion

Among all advanced anode materials, graphite is regarded as leading and still-unrivaled. However, in the modern world, graphite-based anodes cannot fully satisfy the customers because of its insufficient value of specific capacity. Other limitations are being nonrenewable, restricted natural graphite resources, or harsh conditions required for artificial graphite production. All things considered, many efforts have been made in the investigation of novel carbonaceous materials with desired properties produced from natural, renewable resources via facile, low-cost, and environmentally friendly methods. In this work, we obtained N-doped, starch-based carbon aerogels using melamine and N2 pyrolysis as the source of nitrogen. The materials were characterized by X-ray powder diffraction, elemental analysis, X-ray photoelectron spectroscopy, galvanostatic charge–discharge tests, cyclic voltammetry, and electrochemical impedance spectroscopy. Depending on the doping method and the nitrogen amount, synthesized samples achieved different electrochemical behavior. N-doped, bioderived carbons exhibit far better electrochemical properties in comparison with pristine ones. Materials with the optimal amount of nitrogen (such as MCAGPS-N8.0%—carbon aerogel made from potato starch modified with melamine and CAGPS-N1.2%—carbon aerogel made from potato starch modified by N2 pyrolysis) are also competitive to graphite, especially for high-performance battery applications. N-doping can enhance the efficiency of Li-ion cells mostly by inducing more defects in the carbon matrix, improving the binding ability of Li+ and charge-transfer process.

scholarly journals A TiO2 Coated Carbon Aerogel Derived from Bamboo Pulp Fibers for Enhanced Visible Light Photo-Catalytic Degradation of Methylene Blue

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 239
Author(s):  
Jian Zhang ◽  
Wei Yuan ◽  
Tian Xia ◽  
Chenghong Ao ◽  
Jiangqi Zhao ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Three Dimensional ◽  
Carbon Aerogel ◽  
Catalytic Performance ◽  
Catalytic Degradation ◽  
Carbon Aerogels ◽  
Maximum Adsorption Capacity ◽  
X Ray

Carbon aerogels (CA) derived from bamboo cellulose fibers were coupled with TiO2 to form CA/TiO2 hybrids, which exhibited extraordinary performance on the photo-catalytic degradation of methylene blue (MB). The structure and morphology of CA/TiO2 were characterized by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectrum. The CA displayed a highly porous and interconnected three-dimensional framework structure, while introducing the catalytic active sites of TiO2 onto the aerogel scaffold could remarkably enhance its photo-catalytic activity. The adsorption and photo-catalytic degradation of MB by the CA/TiO2 hybrid were investigated. The maximum adsorption capacity of CA/TiO2 for MB was 18.5 mg/g, which outperformed many similar materials reported in the literature. In addition, compared with other photo-catalysts, the present CA/TiO2 demonstrated superior photo-catalytic performance. Almost 85% of MB in 50 mL solution with a MB concentration of 10 mg/L could be effectively degraded by 15 mg CA/TiO2 in 300 min.

scholarly journals Removal of hexavalent chromium from wastewater by Cu/Fe bimetallic nanoparticles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jien Ye ◽  
Yi Wang ◽  
Qiao Xu ◽  
Hanxin Wu ◽  
Jianhao Tong ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Bimetallic Nanoparticles ◽  
Chemical Reduction ◽  
Particle Surface ◽  
Zerovalent Iron ◽  
Order Model ◽  
X Ray ◽  
Nanoscale Zerovalent Iron

AbstractPassivation of nanoscale zerovalent iron hinders its efficiency in water treatment, and loading another catalytic metal has been found to improve the efficiency significantly. In this study, Cu/Fe bimetallic nanoparticles were prepared by liquid-phase chemical reduction for removal of hexavalent chromium (Cr(VI)) from wastewater. Synthesized bimetallic nanoparticles were characterized by transmission electron microscopy, Brunauer–Emmet–Teller isotherm, and X-ray diffraction. The results showed that Cu loading can significantly enhance the removal efficiency of Cr(VI) by 29.3% to 84.0%, and the optimal Cu loading rate was 3% (wt%). The removal efficiency decreased with increasing initial pH and Cr(VI) concentration. The removal of Cr(VI) was better fitted by pseudo-second-order model than pseudo-first-order model. Thermodynamic analysis revealed that the Cr(VI) removal was spontaneous and endothermic, and the increase of reaction temperature facilitated the process. X-ray photoelectron spectroscopy (XPS) analysis indicated that Cr(VI) was completely reduced to Cr(III) and precipitated on the particle surface as hydroxylated Cr(OH)3 and CrxFe1−x(OH)3 coprecipitation. Our work could be beneficial for the application of iron-based nanomaterials in remediation of wastewater.

A Label-Free Electrochemical Aptasensor for the Rapid Detection of Tetracycline Based on Ordered Mesoporous Carbon–Fe3O4

2018 ◽  
Vol 71 (3) ◽  
pp. 170 ◽  
Author(s):  
Xuejia Zhan ◽  
Guangzhi Hu ◽  
Thomas Wagberg ◽  
Dongwei Zhang ◽  
Pei Zhou
Keyword(s):  
Photoelectron Spectroscopy ◽  
Mesoporous Carbon ◽  
Physical Adsorption ◽  
Differential Pulse ◽  
Ordered Mesoporous Carbon ◽  
Label Free ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ordered Mesoporous ◽  
Modification Procedure

A novel aptasensor based on a tetracycline (TET) aptamer immobilized by physical adsorption on an ordered mesoporous carbon–Fe3O4 (OMC-Fe3O4)-modified screen-printed electrode surface was successfully fabricated. OMC-Fe3O4 was characterized by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The modification procedure of the aptasensor was characterized by cyclic voltammetry. Interaction between the TET aptamer and target was determined by differential pulse voltammetry. Under optimal conditions, the proposed aptasensor exhibited good electrochemical sensitivity to TET in a concentration range of 5 nM to 10 μM, with a detection limit of 0.8 nM (S/N = 3). This aptasensor exhibited satisfactory specificity, reproducibility, and stability.

scholarly journals Copper microsphere hybrid mesoporous carbon as matrix for preparation of shape-stabilized phase change materials with improved thermal properties

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yi Liu ◽  
Yan Chen ◽  
Junwei Zhang ◽  
Junkai Gao ◽  
Zhi Han
Keyword(s):  
Thermal Properties ◽  
Phase Change ◽  
Photoelectron Spectroscopy ◽  
Mesoporous Carbon ◽  
Phase Change Materials ◽  
Copper Ions ◽  
Thermal Constant ◽  
Step Method ◽  
Scanning Calorimetry ◽  
X Ray

Abstract Copper microsphere hybrid mesoporous carbon (MPC-Cu) was synthesized by the pyrolysis of polydopamine microspheres doped with copper ions that were prepared using a novel, facile and simple one-step method of dopamine biomimetic polymerization and copper ion adsorption. The resulting MPC-Cu was then used as a supporter for polyethylene glycol (PEG) to synthesize shape-stabilized phase change materials (PEG/MPC-Cu) with enhanced thermal properties. PEG/MPC-Cu was studied by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, differential scanning calorimetry and thermal constant analysis. The results demonstrated that the thermal conductivity of PEG/MPC-Cu was 0.502 W/(m K), which increased by 100% compared to pure PEG [0.251 W/(m K)]. The melting enthalpy of PEG/MPC-Cu was 95.98 J/g, indicating that PEG/MPC-Cu is a promising candidate for future thermal energy storage applications. In addition, the characterization results suggested that PEG-MPC-Cu possessed high thermal stability. Therefore, the method developed in this paper for preparing shape-stabilized phase change materials with improved thermal properties has substantial engineering application prospects.

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.

scholarly journals Studies on phenol removal from wastewater with CTAB-modified bentonite supported KMnO4

2013 ◽  
Vol 3 (3) ◽  
pp. 204-216 ◽  
Author(s):  
Jing Wang ◽  
Hongzhu Ma ◽  
Jie Yu ◽  
Shanshan Wang ◽  
Wenyan He ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Solid Phase ◽  
Phenol Degradation ◽  
Cod Removal ◽  
Phenol Removal ◽  
Solution Ph ◽  
Modified Bentonite ◽  
X Ray ◽  
Cod Removal Efficiency

Cetyltrimethylammonium bromide (CTAB) modified bentonite supported KMnO4 (KMnO4/CTAB-bent) was prepared by solid-phase grinding method, and applied to phenol removal from wastewater. Factors affecting efficiency, such as activated temperature, initial solution pH, KMnO4/CTAB-bent dosage, phenol initial concentration and reaction temperature on degradation were investigated. It was found that pH significantly affected the degradation and chemical oxygen demand (COD) removal efficiency. The results show that over 92% degradation and 60.58% COD removal efficiency can be obtained in 30 min. The surface properties and structure of KMnO4/CTAB-bent were measured by X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller, and Fourier transform infrared spectroscopy. However, it was demonstrated that the KMnO4/CTAB-bent was deactivated quickly during phenol degradation after the second cycle, indicating that the stability of KMnO4/CTAB-bent needs to be further improved.

scholarly journals A new insight into the restriction of Cr(VI) removal performance of activated carbon under neutral pH condition

2021 ◽  
Author(s):  
Yi Fang ◽  
Ke Yang ◽  
Yipeng Zhang ◽  
Changsheng Peng ◽  
Aurora Robledo-Cabrera ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Toxic Heavy Metal ◽  
X Ray ◽  
Neutral Ph ◽  
Removal Capacity ◽  
Ph Conditions ◽  
Neutral Conditions ◽  
The Impact

Abstract Activated carbon has been widely used to remove hazardous Cr(VI), however, the impact of Cr2O3 precipitate on gradually declined removal ability as pH increased has received little attention. Herein, to investigate the effect of Cr2O3, SEM-EDX (scanning electron microscope-energy dispersive X-ray analysis) coupling elements mapping of chromium loaded powder activated carbon (PAC) revealed that a chromium layer was formed on the PAC exterior after being treated with Cr(VI) at pH 7. XPS (X-ray photoelectron spectroscopy) study confirmed that 69.93% and 39.91% Cr2O3 precipitated on the PAC surface at pH 7 and pH 3, respectively, corresponding to 17.77 mg/g and 20 mg/g removal capacity. Exhausted PAC had a removal efficiency of 92.43% after Cr2O3 being washed by H2SO4 solution, which was much higher than the removal efficiency of 51.27 % after NaOH washing. This further verified the intrinsically developed Cr2O3 precipitate on PAC under neutral conditions limited the durability of PAC as an adsorbent. Consecutive elution assessments confirmed that adsorption and reduction ability both declined as pH increased. Raman spectroscopy and C 1s spectra of materials demonstrated two distinct Cr(VI) removal mechanisms under pH 3 and pH 7. In conclusion, the exhausted AC after Cr(VI) adsorption can be rejuvenated after the surface coated Cr2O3 being washed by the acid solution which can expand the longevity of AC and recover Cr(III). HIGHLIGHT In this work, we scrutinized the mechanism of poor removal capacity of commercial activated carbon on toxic heavy metal Cr(VI) under neutral pH conditions. Differing from the most accepted view that electrostatic repulsion is the main consideration, our study suggested that the relatively more Cr2O3 precipitate on the surface of activated carbon under higher pH led to the low Cr(VI) sequestration capability.

scholarly journals in Situ X-ray Photoelectron Spectroscopic and Electrochemical Studies of the Bromide Anions Dissolved in 1-Ethyl-3-Methyl Imidazolium Tetrafluoroborate

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 304 ◽  
Author(s):  
Jaanus Kruusma ◽  
Arvo Tõnisoo ◽  
Rainer Pärna ◽  
Ergo Nõmmiste ◽  
Enn Lust
Keyword(s):  
Photoelectron Spectroscopy ◽  
Mesoporous Carbon ◽  
Residual Water ◽  
Carbon Electrode ◽  
Xps Spectra ◽  
X Ray ◽  
In Situ Xps ◽  
Vacuum Interface ◽  
Photoelectron Peak

Influence of electrode potential on the electrochemical behavior of a 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) solution containing 5 wt % 1-ethyl-3-methylimidazolium bromide (EMImBr) has been investigated using electrochemical and synchrotron-initiated high-resolution in situ X-ray photoelectron spectroscopy (XPS) methods. Observation of the Br 3d5/2 in situ XPS signal, collected in a 5 wt % EMImBr solution at an EMImBF4–vacuum interface, enabled the detection of the start of the electrooxidation process of the Br- anion to Br3- anion and thereafter to the Br2 at the micro-mesoporous carbon electrode, polarized continuously at the high fixed positive potentials. A new photoelectron peak, corresponding to B–O bond formation in the B 1s in situ XPS spectra at E ≤ –1.17 V, parallel to the start of the electroreduction of the residual water at the micro-mesoporous carbon electrode, was observed and is discussed. The electroreduction of the residual water caused a reduction in the absolute value of binding energy vs. potential plot slope twice to ca. dBE dE-1 = –0.5 eV V-1 at E ≤ –1.17 V for C 1s, N 1s, B 1s, F 1s, and Br 3d5/2 photoelectrons.

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