International Journal of Environmental Science and Technology
·
2022
·Vol. 20
·期 6
·6777-6790
·
IF 3.519
Liu H.,Wu S. F.
In situ pore forming achieved by vapor releasing of chemical looping reaction for dynamic compensation of lost pore volume was proposed to improve the durability of the nano-CaO-based adsorbent in calcium looping process. The effect of contents (12–34 wt.%) and kinds of the pore forming agents (MnO 2 , Fe 2 O 3 , Co 2 O 3 , NiO and CuO) on the dynamic pore compensation effect and sorption performance including sorption capacity and durability of the adsorbent was investigated. The results showed that high pore forming capacity could be achieved by high doping content and oxygen mass fraction of agent. Good anti-sintering ability of agent could leads to a prominent pore forming stability. The final dynamic pore compensation effect was controlled by both pore forming capacity and stability. Compared with the nano-CaO/Al 2 O 3 adsorbent, the best dynamic pore compensation effect for the nano-CaO-NiO/Al 2 O 3 adsorbent was achieved with doping NiO content of 21 wt.%, which could increase pore volume by 67.3% after 3 CaL cycles. The total average deactivation rate of the nano-CaO-NiO/Al 2 O 3 adsorbent was reduced by 48%, which meant that in situ dynamic pore compensation could significantly improve the cyclic durability of adsorbents. Graphical abstract
研究领域:
材料科学
·
环境工程
✓ 已验证
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Yun Long,Jian Sun,Changnian Mo,Xiangyao She,Pengxin Zeng,Hongqiang Xia,Jubing Zhang,Zijian Zhou,Xinming Nie,Chuanwen Zhao
Calcium looping (CaL) belongs to a promising high-temperature CO 2 capture technology because of adopting cheap and extensive source CaO-based sorbents . However, CaO-based sorbents are prone to occur the issues of sintering and elutriation in the fluidized-bed reactors. To further enhance the practicability, the Zr-supported, CaO-based sorbent pellets were produced using the graphite-moulding method. Different synthesis modes (i.e., sol-gel, hydration-mixing, and wet-mixing) were compared for preparing CaO-based composite slurry before pelletization. Sol-gel is the promising synthesis mode to prepare Zr-supported, CaO-based pellets with outstanding CO 2 capture performance due to achieving a more uniform distribution of inert CaZrO 3 spacer. Moreover, the Zr-based stabilizer content within sorbent pellets produced by the combined method of sol-gel and graphite-moulding was further studied. The higher content of Zr-based stabilizer promotes the enhancement of cyclic stability and mechanical strength of Zr-supported, CaO-based pellets. After 17 cycles, the sorbent pellets containing 20 wt% of Zr-based stabilizer display a high CaO carbonation conversion of 74.1 %. Moreover, CaO-based pellets with 20 wt% of Zr-based stabilizer possess a higher compression strength of 4.84 ± 1.08 MPa, which is as high as 1.8 times that of the pellets with 5 wt% of Zr-based stabilizer.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2021
·
IF 6.609
Zhonghui Zhang,Changlei Qin,Zhiliang Ou,Hongqiang Xia,Jingyu Ran,Chunfei Wu
It is known that a considerable amount of tar is usually generated in the biomass gasification process, and catalytic steam reforming is an effective method to remove this by-product. The coupling of in-situ CO 2 capture in the process can further shift the forward reforming reaction and produce hydrogen with a high purity. In this work, sorption enhanced steam reforming (SESR) of toluene (as a model compound of biomass tar) was investigated thermodynamically and experimentally using the mechanically mixed Ni/perovskite catalyst and CaO sorbent. It is verified that the appropriate temperature is 650 °C under stoichiometric reaction (S/C = 2), and around 75% average H 2 yield with a maximum H 2 purity over 95% could be obtained. Moreover, the cyclic SESR-regeneration and characterization including XRD, SEM/EDS, TEM and XPS were carried out, and it shows a stable catalytic performance and compatibility of the Ni/perovskite catalyst in the SESR process for high-purity hydrogen production.
研究领域:
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
WASTE MANAGEMENT
·
2022
·
IF 8.816
Chengyang Cao,Yetao Cheng,Hongyun Hu,Hao Wang,Shuai Liu,Ming Hu,Xian Li,Hong Yao
Textile dyeing sludge (TDS) is a typical industrial solid waste whose amount surged with the textile industry's development. Pyrolysis treatment is a promising technique for TDS to realize harmless disposal and resource reuse. However, the high content of organic compounds would cause sulfurous pollutants emission, reducing the economic feasibility during pyrolysis. This study aimed to fill the knowledge gaps about the thermal behavior, products distribution, kinetics, and sulfur transformation during TDS pyrolysis in 350–575 ℃ with the heating rate of 60, 600, and 6000 ℃/min, then investigate the sulfur fixation effect of CaO under representative conditions (350 ℃, 650 ℃ with 60 ℃/min, 6000 ℃/min). The primary decomposition stage of TDS is observed in 127–557 ℃, following the Avrami-Erofeev (n = 3) model, while the activation energy presents a convergent tendency with the increased heating rate. The pyrolysis temperature and heating rates impact the cracking of organic compounds, while a weakening effect is found for the sulfur distribution. CaO addition could efficiently realize sulfur fixation in char by absorbing sulfurous gas products, but SO 2 escape appeared with the increased CaO fraction. Pyrolysis condition at 650 ℃-60 ℃/min with 10 wt% CaO addition is recommended to achieve high sulfur retention, and the sulfur transformation mechanism in char during the TDS pyrolysis with and without CaO is proposed. Our findings provide novel and fundamental insights into the efficient disposal and pollution control during TDS pyrolysis.
研究领域:
环境科学
·
能源工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2023
·Vol. 30
·期 9
·1740-1747
·
IF 4.8
Cai Dawei,Zhang Li,Wang Wanlin,Zhang Lei,Sohn Il
Mold flux serves the crucial metallurgical function of absorbing inclusions, directly impacting the smoothness of the casting process as well as the cast slab quality. In this study, the dissolution behavior and mechanism of TiO 2 and TiN inclusions in molten CaO–SiO 2– B 2 O 3 -based fluorine-free mold flux were explored by in situ single hot thermocouple technology combined with X-ray photoelectron spectroscopy. The results showed that TiO 2 inclusions are effectively dissolved by the molten slag within 76 s, during which the original octahedral [TiO 6 ] 8− structures are destroyed and convert to the networker tetrahedral [TiO 4 ] 4− structures. However, the dissolution rate is much lower for TiN inclusions than for TiO 2 inclusions. This can be attributed to the fact that the TiN particles need to be oxidized and then dissolved in the molten slag to form tetrahedral [TiO 4 ] 4− and octahedral [TiO 6 ] 8− structures during the TiN inclusion dissolution process, which is accompanied by the generation of a large amount of N 2 gas. Moreover, CaTiO 3 crystals tend to nucleate and grow on bubble surfaces with sufficient octahedral [TiO 6 ] 8− structures and Ca 2+ ions, eventually resulting in the molten slag being in a solid–liquid mixed state.
研究领域:
冶金学
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材料科学
·
铸造过程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Shaobo Yang,Yujie Ma,Jiali Li,Sijie Kou,Bo Chen,Chidong Liu,Juanli Deng,Shangwu Fan
Nowadays, Y 2 O 3 –Al 2 O 3 –SiO 2 (YAS) glass joining is considered to be a promising scheme for nuclear-grade continuous silicon carbide (SiC) fiber reinforced SiC matrix composites (SiC/SiC). CaO has great potential for nuclear applications since it has low reactivity and low decay rate under nuclear irradiation. In this paper, the effect of CaO doping on the structure, thermophysical properties , and crystallization behavior of YAS glass was systematically studied. As the CaO doping content increased, the number of bridge oxygens and the viscosity at high temperatures reduced gradually. After heat treatment at 1400 °C, the main phases in YAS glass were β-Y 2 Si 2 O 7 , mullite , and SiO 2 (coexistence of crystalline and glass phases), while that with 3.0% CaO doping turned into a single glassy phase under the same treatment conditions. Moreover, a structural model and the modification mechanism were proposed, which provided a theoretical basis for the subsequent component design and optimization.
研究领域:
材料科学
·
核工程
·
陶瓷
✓ 已验证
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Xianyao Yan,Yingjie Li,Chunxiao Zhang,Yuzhuo Wang,Jianli Zhao,Zeyan Wang
The water gas shift reaction is an important reaction for H 2 production in various industrial applications. The presence of CaO can promote the reactivity of the water gas shift reaction without any catalysts, but the enhancement mechanism of CaO in this reaction is difficult to determine just by the experiment. In this work, the water gas shift reaction along four possible pathways on the CaO surface were studied by density functional theory (DFT) analysis. The energy barriers along the pathways were analyzed to determine the most possible reaction pathway and role of the CaO surface. The DFT calculation results show that the WGS reaction is more prone to proceed along the redox-a pathway probably: H 2 O dissociates into hydroxyl and atomic H spontaneously when H 2 O and CO co-adsorb on the CaO surface, then the hydroxyl continues to dissociate and CO is oxidized by the generated atomic O. Afterwards, H 2 molecule generates from two atomic H, and then CO 2 adsorbs and H 2 desorbs simultaneously on the CaO surface. The CaO surface enables the spontaneous dissociation of H 2 O, which is the rate-limiting step of WGS reaction. The generation of CO 2 is facilitated, and the energy barrier is reduced from 2.304 to 0.757 eV on the CaO surface. Besides, the formation of CO 3 2− on the surface avoids the energy barrier for CO 2 desorption, while the CO 2 also occupies the active site and reduces the enhancement of CaO on WGS reaction. The calculation result reinforces the comprehension on the mechanism of CaO on WGS reaction.
研究领域:
化学工程
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材料科学
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理论化学
✓ 已验证
产品关联
DOI
高影响因子
Environmental Science-Nano
·
2024
·Vol. 11
·期 6
·2550-2567
·
IF 5.8
Ahsan Ayyaz,Iram Batool,Kangni Zhang,Fakhir Hannan,Yongqi Sun,Tongjun Qin,Habib-ur-Rehman Athar,Zafar Ullah Zafar,Muhammad Ahsan Farooq,Weijun Zhou
Nanotechnology has been widely used in agriculture to improve plant growth and stress tolerance. The exogenous application of calcium nanoparticles (CaO NPs) can improve plant tolerance to drought stress. However, the underlying physiological molecular mechanisms are still unclear. Herein, 100 mg L−1 of CaO NPs were applied to rapeseed plants when grown under the conditions of 0–15% w/v PEG-6000 solution. Drought stress reduced the rapeseed growth, CO2 assimilation rate, stomatal conductance, and photosynthetic pigments. The application of 100 mg L−1 CaO NPs improved the growth of rapeseed plants under drought conditions (shoot dry weight, 77%; root dry weight, 69%). Growth improvement due to CaO NPs was positively associated with the photosynthetic rate, quantum yield of photosystem II and quantity of photosynthetic pigments. The net photosynthetic rate (Pn), stomatal conductance (Gs), internal CO2 (Ci), and transpiration rate (Tr) increased by 65%, 85%, 69%, and 67%, respectively. The increases in quantum yield of photosystem II and photosynthetic pigments due to CaO NPs were 85% and 53%, respectively. A positive association between the growth and each of the gas exchange attributes, PSII activity and photosynthetic pigments indicated that CaO NPs improved the photosynthetic rate by reducing stomatal, as well as non-stomatal, limiting factors. The CaO NP treatment also improved the uptake of mineral nutrients under drought stress, including calcium by 82%, and potassium, phosphorous, magnesium, manganese, and boron by 78%, 89%, 72%, 80% and 73%, respectively. Furthermore, the application of CaO NPs caused a greater accumulation of 28 metabolites and reduced the accumulation of 18 metabolites that are mainly related to N-metabolism and amino acid biosynthesis, such as cysteine/homocysteine, lysine, tryptophan, alanine, glutamate, and proline, compared to droughted plants. The application of CaO NPs under drought conditions induced the up-regulation of upstream genes such as CHS, CHI, F3′H, and F3H, early development genes such as PAL, C4H, 4CL1, 4CL5, DFR, and ANS, and late development genes such as UGT78D2, UGT79B1, MT, PAP1, and PAP2 in plants involved in flavonoid biosynthesis expression. The findings of this study suggest that CaO NPs improved the photosynthetic capacity through modulating the stomatal conductance, photosystem II activity, accumulation of nutrients, and reprogramming of both primary and secondary metabolic pathways such as N-metabolism, hormonal and flavonoid biosynthesis for regulating rapeseed growth under drought stress.
研究领域:
植物学
·
农学
·
分子生物学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2020
·
IF 5.578
Xianyao Yan,Yingjie Li,Chaoying Sun,Zeyan Wang
In this work, H 2 production performances from Enteromorpha prolifera and its char by absorption-enhanced steam gasification using Ce-doped CaO material were investigated. The Ce-doped CaO material improves the H 2 production from Enteromorpha prolifera by steam gasification, which achieves 79.0 vol% H 2 in the syngas. The Ce-doped CaO material with the mass ratio of CeO 2 /CaO = 10:90 seems more appropriate for high H 2 production, tar and char conversion. The presence of CeO 2 leads to good cyclic stability in H 2 production from Enteromorpha prolifera char during the gasification/calcination cycles. After 20 cycles, H 2 concentration and yield from Enteromorpha prolifera char achieve 77.8 vol% and 141.8 mL/g using Ce-doped CaO material, respectively. The CeO 2 facilitates the conductivity of electrons in CaO surface due to the existence of Ce 3+ species, thus CO 2 capture, water gas shift, and steam methane reforming reactions are promoted by CeO 2 . The Ce-doped CaO material maintains the porous microstructure and fine particles during the cycles due to the support of CeO 2 . Therefore, H 2 productions from Enteromorpha prolifera and its char by absorption-enhanced steam gasification using Ce-doped CaO material appear promising.
研究领域:
能源与环境科学
·
生物质能
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2022
·
IF 24.319
Chunxiao Zhang,Yingjie Li,Zirui He,Jianli Zhao,Dong Wang
Herein, a hollow microtubular Fe/Mn-promoted CaO-Ca 12 Al 14 O 33 bi-functional material was prepared by the bio-template method and used for H 2 production from sorption enhanced water gas shift (SEWGS). The microtubular Fe/Mn-promoted CaO-Ca 12 Al 14 O 33 exhibits excellent CO 2 capture and H 2 production performance in SEWGS/regeneration cycles. The stable hollow microtubular structure improves available adsorption and catalytic sites in Fe/Mn-promoted CaO-Ca 12 Al 14 O 33 for CO 2 capture and H 2 production. Mn addition improves CO 2 affinity capacity of the microtubular material. The Fe-Mn interaction increases redox ability of Fe 3+ /Fe 3+, 2+ , which promotes CO conversion. Moreover, the formed Ca 2 Fe 2 O 5 and Ca 2 MnO 4 both increase oxygen vacancies to promote catalytic activity of the microtubular material for WGS and its CO 2 capture capacity. The CO conversions for the microtubular material with the Fe/Mn/Al/Ca molar ratio= 10/2/10/100 are 98.7% and 94.0% after 20 cycles under the mild and severe calcination conditions, respectively. The hollow microtubular bi-functional material shows good prospect for efficient H 2 production from SEWGS.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2024
·Vol. 55
·期 4
·2037-2048
·
IF 2.4
Lin Chenlu,Yang Xiao
This study focuses on understanding the behavior of oxide ions (O 2– ) in molten CaCl 2 , which is important for applications in molten salt electrolysis. The dissolution mechanism of solid CaO and mass transfer characteristics of O 2– in molten CaCl 2 were investigated through comprehensive chemical analysis. The results revealed that the incongruently melting compound in the CaCl 2 –CaO system is Ca 4 OCl 6 (CaO·3CaCl 2 ), with a peritectic point observed at 19 mol pct of CaO and 1104 K. The previously reported compounds Ca 3 OCl 4 (CaO·2CaCl 2 ) and Ca 5 OCl 8 (CaO·4CaCl 2 ) were never detected, while only Ca 4 OCl 6 (CaO·3CaCl 2 ) was observed under air-tight conditions. The dissolution behavior of solid CaO in molten CaCl 2 is highly temperature dependent, with a critical threshold identified at 1104 K. Below this temperature, CaO reacts with CaCl 2 to form Ca 4 OCl 6 , which subsequently dissociates into simple ions (Ca 2+ , Cl – , and O 2– ). Above 1104 K, CaO directly dissociates to produce O 2– . Although temperature influences the formation and dissociation of Ca 4 OCl 6 , it has minimal impact on the dissociation of CaO and the mass transfer of O 2– in the melt.
研究领域:
材料科学
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化学工程
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Chengyang Cao,Yang Ren,Hao Wang,Hongyun Hu,Baojun Yi,Xian Li,Linling Wang,Hong Yao
Solar-powered pyrolysis of waste tires has been extensively studied because it can rapidly convert waste tires into valuable gas products using sustainable energy. However, the emitted sulfurous pollutants during this fast pyrolysis process would significantly reduce the economic feasibility of disposal waste tires. In order to investigate and regulate the sulfur transformation behavior, a large-load thermogravimetric analyzer and an optical rapid thermal processor were adopted to characterize and simulate the solar-powered fast pyrolysis behavior. The sulfur fixation effect of CaO was also evaluated in this study. Results showed that CaO addition could increase the emission of H 2 and CO by promoting the cracking of organic compounds in tar. In comparison, it could decrease the CO 2 emission by adsorption or transformation. Also, an excellent sulfur fixation rate in char was achieved with 10 wt% CaO addition, but accompanied by increasing emission tendency of SO 2 , especially at 650 °C-6000 °C/min. It was attributed to the competition reaction between H 2 S and SO 2 in the gas phase and interaction between CaS and CaSO 4 in the condensed phase. Our findings could be beneficial to develop an in-situ sulfur removal method during the pyrolysis of waste tires in the industry.
研究领域:
能源与环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）