scholarly journals Superior Degradation Performance of Nanoporous Copper Catalysts on Methyl Orange

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 913
Author(s):  
Jinyi Wang ◽  
Sen Yang
Keyword(s):  
Activation Energy ◽  
Methyl Orange ◽  
High Efficiency ◽  
Low Cost ◽  
Degradation Process ◽  
Copper Catalysts ◽  
Reaction Rate Constant ◽  
Nanoporous Structure ◽  
Intra Particle Diffusion ◽  
Different Temperatures

The development of low-cost and high-efficiency catalysts for wastewater treatment is of great significance. Herein, nanoporous Cu/Cu2O catalysts were synthesized from MnCu, MnCuNi, and MnCuAl with similar ligament size through one-step dealloying. Meanwhile, the comparisons of three catalysts in performing methyl orange degradation were investigated. One of the catalysts possessed a degradation efficiency as high as 7.67 mg·g−1·min−1. With good linear fitting by the pseudo-first-order model, the reaction rate constant was evaluated. In order to better understand the degradation process, the adsorption behavior was considered, and it was divided into three stages based on the intra-particle diffusion model. Three different temperatures were applied to explore the activation energy of the degradation. As a photocatalytic agent, the nanoporous structure of Cu/Cu2O possessed a large surface area and it also had low activation energy, which were beneficial to the excellent degradation performance.

scholarly journals Adsorption of Cr(VI) and Cu(II) from aqueous solutions by biochar derived from Chaenomeles sinensis seed

2019 ◽  
Vol 80 (12) ◽  
pp. 2260-2272 ◽  
Author(s):  
Xiaoling Hu ◽  
Jianyang Song ◽  
Hongyu Wang ◽  
Wei Zhang ◽  
Bin Wang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
High Efficiency ◽  
Low Cost ◽  
Maximum Adsorption Capacity ◽  
Heavy Metal Remediation ◽  
Chaenomeles Sinensis ◽  
Wide Ph Range ◽  
Different Temperatures ◽  
Isotherms And Thermodynamics ◽  
Ph Range

Abstract In order to utilize the discarded Chaenomeles sinensis seed (CSS) and develop low-cost biochar for heavy metal pollution control, this study pyrolyzed CSS to prepare biochar at three different temperatures (300, 450 and 600 °C). The physicochemical properties of CSS biochar such as elemental composition, surface area, surface morphology and surface functional groups were characterized. Its adsorption properties including kinetics, isotherms and thermodynamics were studied. The results showed that the adsorption equilibrium was reached at 5 h, which was relatively fast. CSS biochar prepared at 450 °C (CSS450) had the maximum adsorption capacity for Cr(VI) and Cu(II), which was 93.19 mg/g and 105.12 mg/g, respectively. The thermodynamic parameter ΔG0 < 0 and the isotherm parameter RL between 0 and 1 all revealed the feasibility and spontaneity of the adsorption process. The removal of Cr(VI) exhibited high efficiency in a wide pH range (1–10), while the removal of Cu(II) was pH-dependent and optimal at pH = 6. The coexisting ions in the solution showed slight inhibition of the adsorption of Cr(VI) and Cu(II). Additionally, Cu(II) exhibited better affinity for CSS450 than Cr(VI) in dynamic adsorption. This is the first study to prepare biochar from CSS and confirms its potential application for heavy metal remediation.

Adsorption of 2,4-Dichlorophenoxyacetic Acid from Aqueous Solution Using Carbonized Chest Nut as Low Cost Adsorbent: Kinetic and Thermodynamic

2020 ◽  
Vol 234 (3) ◽  
pp. 461-484
Author(s):  
Jale Gülen ◽  
Sabri Aslan
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Low Cost ◽  
Isotherm Models ◽  
Particle Diffusion ◽  
Dichlorophenoxyacetic Acid ◽  
Adsorption Dynamics ◽  
Intra Particle Diffusion ◽  
Different Temperatures ◽  
2,4 Dichlorophenoxyacetic Acid

AbstractThe activated carbon was made of carbonized chest nut shell (CCS) and used as low cost adsorbent for 2,4-D (2,4-dichlorophenoxyacetic acid) removal. The experiments were conducted at different temperatures such as 35, 45 and 55 °C and this system represents as L type adsorption behavior. The experimental data were modelled using several isotherm models such as Langmuir, Freundlich, Temkin and Dubinin Radushkevich. The adsorption dynamics were searched by applying pseudo first, pseudo second and intra particle diffusion models. The thermodynamic approach was conducted for determining the thermodynamic values of ΔH°, ΔS° and ΔG°.

Wet And Dry Oxidation of Polycrystalline SixGe1-x Films

1998 ◽  
Vol 533 ◽  
Author(s):  
P.-E. Hellberg ◽  
S.-L. Zhang ◽  
F. M. d'Heurle ◽  
C. S. Petersson
Keyword(s):  
Activation Energy ◽  
Reaction Rate ◽  
Quantitative Description ◽  
Reaction Rate Constant ◽  
Enhancement Effect ◽  
Wet Oxidation ◽  
Simultaneous Oxidation ◽  
Dry Oxidation ◽  
Different Temperatures ◽  
Si Films

AbstractWet and dry oxidations of polycrystalline SixGe1-x, with various compositions have been studied at different temperatures. The growth rate of SiO2 is found to be enhanced by Ge, and the enhancement effect is more pronounced in H2O than in O2. A mathematical model, which assumes simultaneous oxidation of Si and Ge and reduction of GeO2 by free Si available at the growing-oxide/SixGe1-x interface, is found to give a quantitative description of the SiO2 growth during thermal oxidation of SixGe1-x. Kinetic parameters are extracted by comparing the model with experiments. The linear and parabolic rate constants for Si oxidation are determined on control Si (100) wafers and polycrystalline Si films. Simple expressions are used for the interdiffusion of Si and Ge in SixGe1-x. For wet oxidation, the activation energy for the reaction rate constant of Ge oxidation is found to be smaller than that of Si oxidation.

scholarly journals Fe3O4-NPs/Orange-Peel composite as magnetic heterogeneous Fenton-like catalyst towards high-efficiency degradation of methyl orange

2021 ◽  
Author(s):  
Qiang Zhao ◽  
Congcong Zhang ◽  
Xiaoqiang Tong ◽  
Yunling Zou ◽  
Yan Li ◽  
...  
Keyword(s):  
Methyl Orange ◽  
High Efficiency ◽  
Low Cost ◽  
Orange Peel ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Heterogeneous Fenton ◽  
Fe3o4 Nps ◽  
Degradation Ratio ◽  
Co Precipitation

Abstract Fe3O4-NPs/orange-peel (MOP) composite was prepared via one-step in-situ co-precipitation method as magnetic heterogeneous Fenton-like catalyst. The properties of MOP were characterized by SEM, TEM, BET, XRD, FT-IR, TGA and XPS technologies. Its Fenton-like catalytic responses towards removal of methyl orange (MO) were investigated, in which the effects of initial dye concentration, pH, temperature and H2O2 dosage were studied. The MO degradation ratio up to 98.0% was obtained within 20 min in optimized conditions. The catalyst also shows excellent catalytic stability exhibiting nearly 90% degradation ratio in 10th cycle within 20 min, whereas pure Fe3O4-NPs showing only 62.5% in this stage. Due to the stabilization of complexing orange peel hydroxyl to Fe oxide in the composite and its magnetic separation property, Fe3O4-NPs/orange-peel composite exhibits excellent Fenton-like catalytic performance which offers great prospects for low-cost and high-efficiency organic dye wastewater treatment.

scholarly journals Natural Nanoporous Filter Material as a New High-Efficiency Natural Adsorbent to Remove Textile Dyes

2020 ◽  
Vol 15 ◽  
pp. 16-23
Author(s):  
Chin-Ya Kuo ◽  
Hsiao-Han Liu
Keyword(s):  
Uniform Distribution ◽  
High Efficiency ◽  
Low Cost ◽  
Mathematic Model ◽  
Filter Material ◽  
Textile Dyes ◽  
Physical Processes ◽  
Natural Adsorbents ◽  
Different Temperatures ◽  
Time Courses

The objective of this paper is to perform the innovation design of removing most textile dyes that are harmful to the environment and might induce cancer. However, many methodologies had been developed for various chemical and physical processes to remove different dyes, such as ozone oxidation, electrochemical methods, chemical coagulation, hypochlorite oxidation, and adsorption to remove dyes from wastewater. A novel nanoporous filter methodology and mathematic simulations for adsorption were established as an effective medium for removing dyes from wastewater which was compared to other expensive treatments. The different concentrations of the dye liquid are used as a tester, and the different concentrations of nanoporous adsorbent were added in a uniform distribution and were tested with different time courses and under different temperatures. The final readings were measured by a spectrophotometer and fit into a mathematic model. The result indicates that this nanoporous and natural adsorbents are very good at cleaning the dyes in this system. The fit-in mathematic models could be applied in these tests which can be used in the industrial conditions for a low cost without secondary dye pollutions.

scholarly journals A novel biochar derived from cauliflower (Brassica oleracea L.) roots could remove norfloxacin and chlortetracycline efficiently

2017 ◽  
Vol 76 (12) ◽  
pp. 3307-3318 ◽  
Author(s):  
Tingting Qin ◽  
Zhaowei Wang ◽  
Xiaoyun Xie ◽  
Chaoran Xie ◽  
Junmin Zhu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Raw Materials ◽  
Low Cost ◽  
Energy Dispersive Spectrometer ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Solution Ph ◽  
Initial Ph ◽  
Intra Particle Diffusion

Abstract The biochar was prepared by pyrolyzing the roots of cauliflowers, at a temperature of 500 °C under oxygen-limited conditions. The structure and characteristics of the biochar were examined using scanning electron microscopy, an energy dispersive spectrometer, a zeta potential analyzer, and Fourier transform infrared spectroscopy. The effects of the temperature, the initial pH, antibiotic concentration, and contact time on the adsorption of norfloxacin (NOR) and chlortetracycline (CTC) onto the biochar were investigated. The adsorption kinetics of NOR and CTC onto the biochar followed the pseudo-second-order kinetic and intra-particle diffusion models. The adsorption isotherm experimental data were well fitted to the Langmuir and Freundlich isotherm models. The maximum adsorption capacities of NOR and CTC were 31.15 and 81.30 mg/g, respectively. There was little difference between the effects of initial solution pH (4.0–10.0) on the adsorption of NOR or CTC onto the biochar because of the buffering effect. The biochar could remove NOR and CTC efficiently in aqueous solutions because of its large specific surface area, abundant surface functional groups, and particular porous structure. Therefore, it could be used as an excellent adsorbent material because of its low cost and high efficiency and the extensive availability of the raw materials.

Removal of Cu(II) and Ni(II) ions from an aqueous solution using α-Fe2O3 nanoparticle-coated volcanic rocks

2015 ◽  
Vol 72 (12) ◽  
pp. 2154-2165 ◽  
Author(s):  
Xianfang Zhu ◽  
Tiehong Song ◽  
Zhuo Lv ◽  
Guodong Ji
Keyword(s):  
Aqueous Solution ◽  
High Efficiency ◽  
Adsorption Process ◽  
Low Cost ◽  
Volcanic Rocks ◽  
Fe2o3 Nanoparticles ◽  
Combined Control ◽  
Intra Particle Diffusion ◽  
Fe2o3 Nanoparticle ◽  
Pseudo Second Order

An adsorbent, volcanic rocks coated with α-Fe2O3 nanoparticles, was prepared and utilized for the removal of Cu(II) and Ni(II) ions from an aqueous solution. Characterization of the coated volcanic rocks indicated that the α-Fe2O3 nanoparticles were successfully and homogeneously distributed on the volcanic rocks, including penetration into rock pores. Batch experiments were conducted to investigate adsorption performance. The adsorption behavior of both ions was found to best fit a pseudo second-order model and Langmuir isotherm. The maximum adsorption capacities of Cu(II) and Ni(II) ions were 58.14 mg g−1 and 56.50 mg g−1 at 293 K, respectively, and increased with rising temperature. The loaded α-Fe2O3 nanoparticles onto volcanic rock significantly increased removal of Cu(II) and Ni(II) ions. The adsorption process was combined control of film diffusion and intra-particle diffusion. Adsorption thermodynamics indicated the adsorption process was spontaneous and occurred mainly through chemisorption. The results confirmed that the volcanic rocks coated with α-Fe2O3 nanoparticles acted as a high-efficiency and low-cost absorbent, and effectively removed Cu(II) and Ni(II) from wastewater.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

Improvement of Ti/RuO2–IrO2 Anode Lifetime and Electrocatalytical Properties by Using an Eco-Friendly Thermal Decomposition Method Using Polyvinyl Alcohol as Solvent

2019 ◽  
Author(s):  
Charlys Bezerra ◽  
Géssica Santos ◽  
Marilia Pupo ◽  
Maria Gomes ◽  
Ronaldo Silva ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Polyvinyl Alcohol ◽  
High Efficiency ◽  
Electrochemical Impedance ◽  
Pechini Method ◽  
Low Cost ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Calcination Temperatures ◽  
Service Lifetime

<p>Electrochemical oxidation processes are promising solutions for wastewater treatment due to their high efficiency, easy control and versatility. Mixed metal oxides (MMO) anodes are particularly attractive due to their low cost and specific catalytic properties. Here, we propose an innovative thermal decomposition methodology using <a>polyvinyl alcohol (PVA)</a> as a solvent to prepare Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes. Comparative anodes were prepared by conventional method employing a polymeric precursor solvent (Pechini method). The calcination temperatures studied were 300, 400 and 500 °C. The physical characterisation of all materials was performed by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy, while electrochemical characterisation was done by cyclic voltammetry, accelerated service lifetime and electrochemical impedance spectroscopy. Both RuO<sub>2</sub> and IrO<sub>2</sub> have rutile-type structures for all anodes. Rougher and more compact surfaces are formed for the anodes prepared using PVA. Amongst temperatures studied, 300 °C using PVA as solvent is the most suitable one to produce anodes with expressive increase in voltammetric charge (250%) and accelerated service lifetime (4.3 times longer) besides reducing charge-transfer resistance (8 times lower). Moreover, the electrocatalytic activity of the anodes synthesised with PVA toward the Reactive Blue 21 dye removal in chloride medium (100 % in 30 min) is higher than that prepared by Pechini method (60 min). Additionally, the removal total organic carbon point out improved mineralisation potential of PVA anodes. Finally, this study reports a novel methodology using PVA as solvent to synthesise Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes with improved properties that can be further extended to synthesise other MMO compositions.</p>

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