APPLIED CATALYSIS B-ENVIRONMENTAL
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2016
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IF 8.328
Lun Pan,Tahir Muhammad,Lu Ma,Zhen-Feng Huang,Songbo Wang,Li Wang,Ji-Jun Zou,Xiangwen Zhang
ZnO is an important semiconductor that has been widely applied in solar cell, photocatalysis, environmental remediation. Doping and morphology control are important approaches to improve its photocatalytic performance. Herein, a facile two-step calcination method was developed to fabricate carbon(C)-doped cubic ZnO with porous structure from zeolite imidazolate frameworks (ZIF-8). Compared with one-step pyrolysis, the approach of two-step calcination not only retains the cubic morphology with inter-connected ZnO nanoparticles and porous structure but also introduces C doping in ZnO lattice effectively. This morphology has advantage in charge transfer, optical absorption and mass transfer during the photoreaction, and C doping results in high charge-separation efficiency. The sample C350-400 (C-doped ZnO, firstly calcined at 350 °C for 2 h from ZIF-8, then 400 °C for 1 h) shows the maximum photoactivity, which is ca . 3-fold and 4-fold higher than ZnO (C450) in photodegradation and PEC water splitting (under UV–vis irradiation), respectively. It is expected that the preparation of metal oxide from MOF is a very promising way to fabricate highly efficient photocatalyst.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
Sustainability
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2022
·Vol. 14
·期 15
·9051
·
IF 3.889
Yufeng Guo,Chao Wang,Shuai Wang,Feng Chen,Xueyuan Wang,Zhiwei An,Lingzhi Yang
Vanadium tailings are a common solid waste in the vanadium industry. As they are rich in Fe, vanadium tailings could be a potential raw material for the blast furnace. However, the presence of approximately 4% Na2O in vanadium tailings is a major impediment to its return to the blast furnace. A novel method for removing sodium from vanadium tailings by calcification roasting and subsequent NaOH leaching was proposed in this work. The method demonstrated that calcification roasting of vanadium tailings can not only volatilize a part of sodium but also facilitate the dissolution of sodium during the subsequent NaOH leaching process. The thermodynamic analysis and behaviors of vanadium tailings during calcification roasting were systematically investigated. The transformation of sodium-containing phases in vanadium tailings during calcification roasting was studied. Further, the promoting effect of calcification roasting on sodium leaching by NaOH was clarified. The total removal efficiency of sodium was 80.37% under optimal conditions, and the residue obtained after sodium removal can be used as a raw material in the blast furnace process for in-plant recycling.Keywords:vanadium tailings;sodium removal;calcification roasting;volatilization;leaching
研究领域:
冶金学
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环境工程
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DOI
高影响因子
Materials Today Communications
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2023
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IF 3.8
Jianhui Su,Yan Liu,Xiujing Peng,Guoxin Sun,Xuchuan Jiang
Due to the high activation energy barrier and the sporadic nature of nucleation, the temperature required for the transition from cubic dense γ-Al 2 O 3 to tripartite α-Al 2 O 3 is as high as 1100–1200 °C. In this work, a two-step strategy was employed to reduce the phase transformation temperature, and prepare α-Al 2 O 3 particles with good dispersion. As the first step, 10 nm sheet γ-Al 2 O 3 was obtained by ammonium aluminum carbonate (AACH) decomposition, which was more favorable to the crystal transformation in the next ball-milling processing. In the second step, γ-Al 2 O 3 powder with partial α-Al 2 O 3 produced in situ by ball-milling γ-Al 2 O 3 was calcined, and α-Al 2 O 3 nanoparticles were obtained at just 850 °C. The content of the α-Al 2 O 3 is determined by the Rietveld Refine method. The relationship between ball-milling time and α-Al 2 O 3 content was clarified, and the effect of α-Al 2 O 3 content on the transformation temperature and morphology of γ-Al 2 O 3 was discussed. The results showed that the α-Al 2 O 3 content rises with the increase of ball milling time, and spherical α-Al 2 O 3 nanoparticles can be obtained when the α-Al 2 O 3 content is 5 %. The addition of α-Al 2 O 3 seeds reduces the phase transition temperature but agglomeration exists. Our proposed two-step low-temperature calcination strategy is an important method for the preparation of alumina nanoparticles
研究领域:
材料科学
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化学工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2014
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IF 4.058
Shams Ali Baig,Jin Zhu,Lisha Tan,Xiaoqin Xue,Chen Sun,Xinhua Xu
Elevated concentration of arsenic in water supplies is detected worldwide and therefore becomes a global issue. Calcination process is known to increase the adsorbent hardness for its effective application in column-based treatment. In this study, magnetic honeycomb briquette cinders (MHBC) and its calcined products: MHBC(A) and MHBC(N) were employed for the adsorptive removal of As(III) in fixed-bed column. Characterizations revealed that the calcination at 1000 °C under nitrogen has significantly increased the adsorbent particles size; favored phase transformation and improved saturation magnetization (>20 emu g − 1 ). Additionally, the new iron silicate phase (Fe 2 SiO 4 ) in aqueous medium generated highly reactive iron oxide species (=FeOOH), which effectively bind As(III) from the influent water by ligand exchanges. In contrast, calcination under dynamic air drastically reduced the saturation magnetization (<1 emu g − 1 ) and assisted to form segregated magnetite, quartz and hematite, as revealed in XRD patterns. The breakthrough curve of each column was compared with Thomas model and found that the model could be applied to estimate As(III) adsorption in fixed-bed column. Thomas model suggested parameters follow the order: MHBC(N) > MHBC > MHBC(A) and the maximum solid phase concentration ( q T ) was found to be about 56.07 mg g − 1 for MHBC(N). The column beds could be successfully regenerated using 200 bed volume of 10% NaOH solution. This study suggests that the selective calcination process need to be integrated with the adsorbent development process for the efficient removal of As(III) from contaminated water using column-based treatment.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
Catalysts
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2022
·Vol. 12
·期 12
·1635
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IF 4.501
Mingjun Wang,Che Li,Bingfang Liu,Wenzhen Qin,Yu Xie
Heterojunction photocatalytic materials show excellent performance in degrading toxic pollutants. This study investigates the influence of calcination temperature on the performances of floral Bi2O3/TiO2composite photocatalyst crystal, which was prepared with glycerol, bismuth nitrate, and titanium tetrachloride as the major raw materials via the solvothermal method. XRD, SEM/TEM, BET, Uv-vis, and XPS were employed to analyze the crystal structure, morphology, specific surface area, band gap, and surface chemical structure of the calcined temperature catalysts. The calcination temperature influence on the catalytic performance of composite photocatalysis was tested with rhodamine B (RhB) as the degradation object. The results revealed the high catalytic activity and higher photocatalytic performance of the Bi2O3/TiO2catalyst. The degradation efficiency of the Bi2O3/TiO2catalyst to RhB was 97%, 100%, and 91% at 400 °C, 450 °C, and 500 °C calcination temperatures, respectively, in which the peak degradation activity appeared at 450 °C. The characterization results show that the appropriate calcination temperature promoted the crystallization of the Bi2O3/TiO2catalyst, increased its specific surface area and the active sites of catalytic reaction, and improved the separation efficiency of electrons and holes.Keywords:calcination temperature;Bi2O3/TiO2compound;visible light;photodegradation
研究领域:
材料科学
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环境化学
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光催化
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DOI
高影响因子
Metals
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2023
·Vol. 13
·期 2
·250
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IF 2.9
Hui Ge,Zhigang Pan,Feng Xie,Diankun Lu,Wei Wang,Shulin Wu
The jarosite residue is a harmful byproduct of the zinc hydrometallurgical process and has been classified as hazardous waste due to its high content of heavy metals and poor stability. In this work, the recovery of valuable metals by synergistic disposal of jarosite residue with cement kiln has been investigated. A series of investigations were undertaken to assess the effect of amount of jarosite residue, roasting time, and the addition of CaCl2on phase transformation and migration of valuable elements in the cement clinker. When 25% of jarosite residue was added to the raw cement materials and roasted at 1400 °C for 30 min, the silicate content in the cement clinker reached 54.4%. In the presence of CaCl2as the mineralizer, the volatilization rates of Pb and Zn were 93% and 75%, respectively. The results indicated that jarosite residue can be used as the cement additive and valuable metals of Pb and Zn can be recovered simultaneously during the roasting process.Keywords:jarosite residue;cement;Pb and Zn;synergistic roasting
研究领域:
环境科学
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冶金工程
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DOI
高影响因子
CERAMICS INTERNATIONAL
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2022
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IF 5.532
Haiping Zhou,Gang Wang,Liping Wang,Zhenhua Zhang,Huiliang Hou,Qifan Zhong,Jin Xiao
Industrial alumina was used as raw material in the high-temperature calcination process, and AlF 3 was introduced to promote mass transfer in the gas phase. The calcination environment, such as sealing, calcination temperature, and holding time, was analyzed to enhance the effect of AlF 3 to promote the crystal growth of alumina. Here, round-like flake α-Al 2 O 3 with an average particle size (D50) of about 18–38 μm were obtained at low dosages (0.1–0.4 wt%) of AlF 3 . The morphology and particle size of α-Al 2 O 3 were further adjusted by introducing different types of micron-scaled nuclei as template inducers. Round-like flake and spherical-like large single crystals α-Al 2 O 3 with an average particle size greater than 35 μm were obtained, respectively, with 65 wt% of 15 μm flake and 10 μm bulk α-Al 2 O 3 nuclei added. In addition, the regulation mechanism of AlF 3 and nuclei on alumina crystal growth was also discussed. Finally, a theoretical basis and technical support for preparing high-performance, low-cost, and high thermal conductivity alumina fillers was provided.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2017
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IF 6.035
He Chen,Xiaojuan Jia,Mingjie Wei,Yong Wang
Ceramic nanofiltration (NF) membranes are of particular significance for molecular separations under harsh conditions. However, they are usually manufactured by the sol-gel process which frequently suffers from low efficiency and poor control in the membrane properties. Herein we demonstrate an efficient and more controllable strategy to produce ceramic tubular NF membranes based on atomic layer deposition (ALD). Tubular ceramic membranes with pore size of ~5 nm are used as the substrates, on which titanium alkoxide (titanicone) is ALD-deposited. Subsequent calcination in air degrades the organic moieties in titanicone, thus converting the dense layer of titanicone into a microporous layer of TiO 2 . This microporous TiO 2 layer serves as a thin separation layer delivering the NF size-sieving function. The thickness of the TiO 2 layer can be readily tuned by changing the ALD cycle numbers, and correspondingly the original substrate membranes are progressively tightened with rising ALD cycles, and the membrane with 300 cycles exhibits a molecular-weight-cut-off (MWCO) of ~680 Da and water permeability of 30 L m −2 h −1 bar −1 . Such a water permeability is higher than many other ceramic tubular membranes with similar MWCOs because of the ultrathin nature of the microporous TiO 2 layer established by titanicone deposition and calcination.
研究领域:
材料科学
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分离技术
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DOI
高影响因子
Journal of Cleaner Production
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2017
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IF 5.715
Lingjun Kong,Minhua Su,Yan Peng,Li'an Hou,Juan Liu,Haipeng Li,Zenghui Diao,Kaimin Shih,Ya Xiong,Diyun Chen
Because of the widespread application of activated carbon (AC) as adsorbents, reduced production costs are highly desirable, therefore, inexpensive alternatives for activated carbon precursors and eco-procedures are presently sought. In this work, AC was successfully prepared from sawdust through co-calcinations with limestone. The surface area and porosity of the resulting ACs were evaluated according to the N 2 adsorption at 77 K. Acid Orange II (AOII) was utilized as a negative dye to study the potential of the resulting AC as an adsorbent. Results revealed that the surface area and total pore volume were both increased greatly. When the activated carbon was prepared in mass ratios of 1:2 and 1:1 (calcium carbonate to sawdust), the surface area increased to 611.4 and 706.9 m 2 /g, respectively, and the adsorption capacities increased to 310.89 and 389 mg/g. These enhancements indicated efficient activation, resulting in energy-saving and environmentally friendly activated carbon production. Thus, this paper provides a cleaner process for producing activated carbon from waste sawdust through bioresource recycling.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
MATERIALS LETTERS
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2022
·
IF 3.574
Zhiliang Zhou,Debao Liu,Zelong Wang,Baosheng Xu
Nd 2 Zr 2 O 7 microbelts were successfully prepared by simple electrospinning paired with calcination . The composition, microstructure, and structure of the as-prepared Nd 2 Zr 2 O 7 microbelts were systematically characterized through a combination of characterisations, such as XRD , SEM, TEM, FT-IR, and TG-DSC techniques. Results indicated that the as-prepared Nd 2 Zr 2 O 7 microbelts had a pyrochlore-type crystal structure and uniform size with about 10 μm thickness. Moreover, a feasible formation mechanism of the Nd 2 Zr 2 O 7 microbelts was discussed. The present procedure can be expanded to develop other rare-earth zirconate materials with belt structure.
研究领域:
材料科学
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无机化学
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产品关联
DOI
高影响因子
Materials Today Communications
·
2023
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IF 3.8
Jiaming Li,Youjian Yang,Wenju Tao,Zhaowen Wang,Jiangyu Yu,Jiaxin Yang,Zhibo Liu
As China's aluminum electrolysis industry expanded its production capacity, it produced a large amount of bath materials– cryolite based molten salt, which is not utilized fast enough and piled up in aluminum factories. It is of great significance to find a proper way to process the accumulated bath materials. Through the method introduced in this paper, aluminum fluoride can be produced from cryolite-based electrolyte and fed back into the aluminum electrolysis cell as a necessary additive. This method includes four steps: Calcination of crystalline aluminum nitrate with cryolite. Cryolite and crystalline aluminum nitrate are mixed and preheated. The main chemical reaction that occurs in this step will produce sodium nitrate (NaNO 3 ), β-aluminum fluoride (β-AlF 3 ), chiolite (Na 5 Al 3 F 14 ) and the aluminum hydroxyfluoride hydrate (AHF). After calcination, the products are washed with water to separate soluble NaNO 3 from the other products. The insoluble products obtained after washing are calcined with ammonium bifluoride to convert AHF into AlF 3 . The mixture obtained after preheating is then washed with an aqueous solution of aluminum salt (such as Al(NO 3 ) 3 ) to remove Na 5 Al 3 F 14 . Aluminum fluoride of high purity is obtained in the end. Calcination step is the most important among the four steps. The effects of calcination temperature (85 – 135 ℃) and molar ratio of crystalline aluminum nitrate to cryolite (0.5 – 2) on the conversion rate of cryolite were studied. The experimental results show that the highest conversion rate of cryolite can reach 97.03%. Through SEM, EDS , ICP and other analysis methods, it was found the final products contained more than 98.8 wt% aluminum fluoride and less than 0.4 wt% sodium, and the average particle size of aluminum fluoride is approximately 15 – 20 µm.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
PLoS One
·
2014
·Vol. 9
·期 6
·e100704
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IF 3.534
Shams Ali Baig,TianTian Sheng,Chen Sun,XiaoQin Xue,LiSha Tan,XinHua Xu
The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe 3 O 4 -HBC prepared at different temperatures (400°C and 1000°C) and environment (air and nitrogen) were investigated for the adsorptive removal of As(V) and As(III) from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe 3 O 4 -HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe 2 SiO 4 ) via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site ( = FeOOH) was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe 3 O 4 -HBC-1000°C(N 2 )>Fe 3 O 4 -HBC (uncalcined)>Fe 3 O 4 -HBC-400°C(N 2 )>Fe 3 O 4 -HBC-400°C(air)>Fe 3 O 4 -HBC-1000°C(air) and the maximum As(V) and As(III) adsorption capacities were found to be about 3.35 mg g −1 and 3.07 mg g −1 , respectively. The adsorption of As(V) and As(III) remained stable in a wider pH range (4–10) using Fe 3 O 4 -HBC-1000°C(N 2 ). Additionally, adsorption data fitted well in pseudo-second-order ( R 2 >0.99) rather than pseudo-first-order kinetics model. The adsorption of As(V) and As(III) onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher) strongly inhibited As(V) and As(III) removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water.
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）