scholarly journals Synthesis of ZnO-CuO and ZnO-Co3O4 Materials with Three-Dimensionally Ordered Macroporous Structure and Its H2S Removal Performance at Low-Temperature

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1925
Author(s):  
Tao Yu ◽  
Zhuo Chen ◽  
Yundong Wang ◽  
Jianhong Xu

H2S is a common but hazardous impurity in syngas, biogas, or natural gas. For some advanced power generation technologies, such as integrated gasification combined cycle (IGCC), solid oxide fuel cells, H2S content needs to be reduced to an acceptable level. In this work, a series of highly porous Zn-Cu and Zn-Co composites with three-dimensionally ordered macropores (3DOM) structure were synthesized via the colloidal crystal template method and used to remove H2S at 150 °C and one atm. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption studies, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were carried out to analyze the fresh and spent adsorbents. The results show that all the adsorbents possess well-ordered macropores, a large surface area, and a highly dispersed active phase. The relative content of Zn and (Cu or Co) has a significant influence on the desulfurization performance of adsorbents. The addition of CuO significantly increases the sulfur capacity and 3DOM-Zn0.5Cu0.5 shows the largest sulfur capacity of all the adsorbents, reaching up to 102.5 mg/g. The multiple adsorption/regeneration cycles of 3DOM-Zn0.5Cu0.5 and 3DOM-Zn0.5Co0.5 indicate that the as-prepared adsorbents are stable, and the sulfur capacity can still exceed 65% of the fresh adsorbents after six cycles.

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
N. Cruz-González ◽  
O. Calzadilla ◽  
J. Roque ◽  
F. Chalé-Lara ◽  
J. K. Olarte ◽  
...  

In the last decade, the urgent need to environmental protection has promoted the development of new materials with potential applications to remediate air and polluted water. In this work, the effect of the TiO2 thin layer over MoS2 material in photocatalytic activity is reported. We prepared different heterostructures, using a combination of electrospinning, solvothermal, and spin-coating techniques. The properties of the samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, UV-Vis diffuse reflectance spectroscopy (UV-Vis-DRS), and X-ray photoelectron spectroscopy (XPS). The adsorption and photocatalytic activity were evaluated by discoloration of rhodamine B solution. The TiO2-MoS2/TiO2 heterostructure presented three optical absorption edges at 1.3 eV, 2.28 eV, and 3.23 eV. The high adsorption capacity of MoS2 was eliminated with the addition of TiO2 thin film. The samples show high photocatalytic activity in the visible-IR light spectrum.


2020 ◽  
Vol 13 (02) ◽  
pp. 2051004
Author(s):  
Jinyan Xiong ◽  
Wei Li ◽  
Kai Zhao ◽  
Weijie Li ◽  
Gang Cheng

Nanocrystallite aggregates have great potential in semiconductor-based photocatalysis toward environmental pollution removal. In this work, we reported the fabrication of broccoli-like zinc oxide nanoaggregates in the presence of beta-cyclodextrin in ethylene glycol-H2O medium. The composition and structure of the as-obtained ZnO nanoaggregates were characterized by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption. It was observed that the beta-cyclodextrin played an important role in the fabrication of such broccoli-like structure. A plausible formation mechanism was discussed on the basis of the controllable experiments. The photocatalytic performance of the products was studied through the photodegradation of rhodamine B under simulated sunlight irradiation. Compared to the spherical ZnO nanoaggregates and ZnO broken spheres, the broccoli-like ZnO exhibited superior photocatalytic efficiency. Based on the photocurrent and electrochemical measurement results, the higher separation efficiency of the photogenerated carriers and lower recombination efficiency of the photoinduced electron–hole pairs over the broccoli-like ZnO nanoaggregates contributed to their remarkable photocatalytic activity.


NANO ◽  
2013 ◽  
Vol 08 (05) ◽  
pp. 1350050
Author(s):  
MIN GUAN ◽  
HAI-PENG BI ◽  
ZUYUAN WANG ◽  
SHAOHUA BU ◽  
LING HUANG ◽  
...  

Mesoporous silicas SBA-15 are modified with β-Cyclodextrins (β-CD) by simple grafting method. β-CD functionalized SBA-15 was characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), nitrogen adsorption–desorption measurements, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Furthermore, the applicability of it is investigated through studying the adsorption properties of clenbuterol. It showed better adsorption capacities of clenbuterol than pure SBA-15. β-CD functionalized SBA-15 material has the potential applications in the treatment of clenbuterol contamination in food and environment science.


2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Nguyen Thi Lan ◽  
Vo Hoang Anh ◽  
Hoang Duc An ◽  
Nguyen Phi Hung ◽  
Dao Ngoc Nhiem ◽  
...  

In this study, C-N-S-tridoped TiO2 composite was fabricated from TiO2 prepared from ilmenite ore and thiourea by means of hydrothermal method. The obtained material was characterized by X-ray diffraction, Raman scattering spectroscopy, UV-Vis diffuse reflectance spectroscopy, nitrogen adsorption-desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). It was found that C-N-S-tridoped TiO2 material has a large specific surface area, showing good photocatalytic activity on the degradation of antibiotic tetracycline in visible light region. The study on the mechanism of tetracycline photodegradation using the liquid chromatography with mass spectrometry was performed. It was found that tetracycline has been degraded over C-N-S-tridoped TiO2 catalyst into many different intermediates which can eventually be converted into CO2 and H2O. The kinetics of photocatalytic decomposition of tetracycline were investigated. In addition, the obtained material could catalyze well the degradation of other antibiotics (ciprofloxacin and chloramphenicol) and dyes (rhodamine-B, methylene blue, and organe red). The catalyst was stable after five recycles with slight loss of catalytic activity, which indicates great potential for practical application of C-N-S-tridoped TiO2 catalyst in treatment of wastewater containing tetracycline in particular or antibiotics in general.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3288
Author(s):  
Anna Rokicińska ◽  
Tomasz Berniak ◽  
Marek Drozdek ◽  
Piotr Kuśtrowski

The paper discusses a formation of Mt–PAA composite containing a natural montmorillonite structure partially exfoliated by poly(acrylic acid) introduced through intercalation polymerization of acrylic acid. Mt–PAA was subsequently modified by controlled adsorption of Co2+ ions. The presence of aluminosilicate packets (clay) and carboxyl groups (hydrogel) led to the deposition of significant amounts of Co2+ ions, which after calcination formed the Co3O4 spinel particles. The conditions of the Co2+ ions’ deposition (pH, volume and concentration of Co(NO3)2 solution, as well as a type of pH-controlling agent) were widely varied. Physicochemical characterization of the prepared materials (including X-ray fluorescence (XRF), X-ray powder diffraction (XRD), low-temperature nitrogen adsorption, X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (H2-TPR)) revealed that the modification conditions strongly influenced the content as well as the distribution of the Co3O4 active phase, tuning its reducibility. The latter parameter was, in turn, very important from the point of view of catalytic activity in the combustion of aromatic volatile organic compounds (VOCs) following the Mars–van Krevelen mechanism.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Hongyan Xu ◽  
Libo Gao ◽  
Qiang Zhang ◽  
Junyang Li ◽  
Jiangtao Diwu ◽  
...  

Co3O4nanoparticles were fabricated by a novel, facile, and environment-friendly carbon-assisted method using degreasing cotton. Structural and morphological characterizations were performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The component of the sample obtained at different temperatures was measured by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Nitrogen adsorption and desorption isotherms were utilized to reveal the specific surface areas. The formation mechanism of Co3O4nanoparticles was also proposed, demonstrating that the additive degreasing cotton played an indispensable role in the process of synthesizing the sample. The resultant Co3O4sample calcined at 600°C exhibited superior electrochemical performance with better specific capacitance and long-term cycling life, due to its high specific surface areas and pores structures. Additionally, it has been proved that this facile synthetic strategy can be extended to produce other metal oxide materials (e.g., Fe3O4). As a consequence, the carbon-assisted method using degreasing cotton accompanied a promising prospect for practical application.


Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 774 ◽  
Author(s):  
Chihao Lin ◽  
Dejian Shi ◽  
Zhentao Wu ◽  
Lingfeng Zhang ◽  
Zhicai Zhai ◽  
...  

In this study, a bimetallic oxide catalyst of cobalt-manganese (CoMn2O4) was synthesized using the sol-gel method, and it was then characterized using a variety of techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) spectroscopy, X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption–desorption isotherms. The obtained novel catalyst, i.e., CoMn2O4, was then used as an activator of peroxymonosulfate (PMS) for the catalytic degradation of a commonly-used UV filter, 2-phenylbenzimidazole-5-sulfonic acid (PBSA) in water. The effects of various factors (e.g., catalyst dosage, PMS concentration, reaction temperature, and pH) in the process were also evaluated. Chemical scavengers and electron paramagnetic resonance (EPR) tests showed that the •OH and SO4•− were the main reactive oxygen species. Furthermore, this study showed that CoMn2O4 is a promising catalyst for activating PMS to degrade the UV filters.


2019 ◽  
Vol 8 (1) ◽  
pp. 661-670 ◽  
Author(s):  
Zafar Khan Ghouri ◽  
Moaaed Motlak ◽  
Shagufta Afaq ◽  
Nasser A. M. Barakat ◽  
Ahmed Abdala

AbstractBoth selenium and reduced graphene oxide have low specific capacitance due to their chemical nature. Nevertheless, their specific capacitance could be enhanced by hybridizing Se nanomaterials with reduced graphene oxide via formation of electrochemical double layer at their interfacial area. Therefore, novel Se-nanorods/rGO nanocomposite was successfully synthesized by template free hot reflux route starting with graphene oxide and selenium dichloride. The composite of rGO decorated by Se-nanorods is characterized using X-ray diffractometry (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption– desorption. The unique architecture of the composite exhibits high specific capacitance of 390 F/ g at 5 mV/s scan rate in 1.0 M KOH solution with ~ 90% cyclic stability after 5000 cycles making it very promising electrode material for supercapacitor applications.


2020 ◽  
pp. 99-111
Author(s):  
Vontas Alfenny Nahan ◽  
Audrius Bagdanavicius ◽  
Andrew McMullan

In this study a new multi-generation system which generates power (electricity), thermal energy (heating and cooling) and ash for agricultural needs has been developed and analysed. The system consists of a Biomass Integrated Gasification Combined Cycle (BIGCC) and an absorption chiller system. The system generates about 3.4 MW electricity, 4.9 MW of heat, 88 kW of cooling and 90 kg/h of ash. The multi-generation system has been modelled using Cycle Tempo and EES. Energy, exergy and exergoeconomic analysis of this system had been conducted and exergy costs have been calculated. The exergoeconomic study shows that gasifier, combustor, and Heat Recovery Steam Generator are the main components where the total cost rates are the highest. Exergoeconomic variables such as relative cost difference (r) and exergoeconomic factor (f) have also been calculated. Exergoeconomic factor of evaporator, combustor and condenser are 1.3%, 0.7% and 0.9%, respectively, which is considered very low, indicates that the capital cost rates are much lower than the exergy destruction cost rates. It implies that the improvement of these components could be achieved by increasing the capital investment. The exergy cost of electricity produced in the gas turbine and steam turbine is 0.1050 £/kWh and 0.1627 £/kWh, respectively. The cost of ash is 0.0031 £/kg. In some Asian countries, such as Indonesia, ash could be used as fertilizer for agriculture. Heat exergy cost is 0.0619 £/kWh for gasifier and 0.3972 £/kWh for condenser in the BIGCC system. In the AC system, the exergy cost of the heat in the condenser and absorber is about 0.2956 £/kWh and 0.5636 £/kWh, respectively. The exergy cost of cooling in the AC system is 0.4706 £/kWh. This study shows that exergoeconomic analysis is powerful tool for assessing the costs of products.


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