GREEN CHEMISTRY
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2022
·Vol. 24
·期 6
·2613-2623
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IF 11.034
Zhao Sun,Hanpeng Liu,Sam Toan,Weizhi Shi,Dongfang Cheng,Zhiqiang Sun
Biomass to hydrogen production has been regarded as a potential approach for green hydrogen synthesis. However, carbon dioxide and bio-tar are inevitably produced, which critically restricts the refinement of biomass-derived syngas. In this study, deoxygenation-enhanced chemical looping biomass gasification (DE-CLBG) is proposed for hydrogen-rich syngas production together with CO2/H2O deoxygenation and catalytic bio-tar removal using the composite Fe/CaO as the deoxidizer. The DE-CLBG process is comprised of a deoxygenated gasification stage and a regeneration stage. During the deoxygenated gasification stage, the deoxidizer is converted under steam gasification via CaO + Fe + O2− → Ca2Fe2O5 with biochar generation; at the regeneration stage, biochar is further gasified with the achievement of deoxidizer reduction via Ca2Fe2O5 + C → CaO + Fe + COx. Experimental results show that the hydrogen production and maximum concentration upon applying 0.300 g of deoxidizer per g of biomass are 6.70 mmol and 89.61 vol%, which was increased by 287% and 27%, respectively, compared with the non-deoxygenated process. Results from the Mössbauer spectrum show that Fe0 is finally transformed into Fe3+ in the form of Ca2Fe2O5 and a small amount of Fe3O4, corresponding to the deoxygenation efficiency of 99.21%. The NMR results imply that aromatic carbon is the main form in biochar whether introducing deoxidizer or not, and deoxygenation can promote the removal of O-alkyl C.
研究领域:
能源科学
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化学工程
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环境科学
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CERAMICS INTERNATIONAL
·
2017
·Vol. 43
·期 16
·13810-13816
·
IF 2.986
Qingong Zhu,Huanping Wang,Ying Tian,Ren Gao,Shilong Zhao,Lihui Huang,Shiqing Xu,Xianghua Zhang
Glass system with compositions of 93.9% ( x CaO- y Al 2 O 3 - z SiO 2 )−5% MgO-1% B 2 O 3 −0.1% Fe 2 O 3 has been prepared by a conventional melt-quenching technique, and the glass forming region and the mechanical properties of the derived glasses were investigated. The approximate glass forming region was found to be x = 10～35%, y = 10～35% and z = 50～80%, while the rest of the area was crystallization zone or crack zone. As x = 10%, y = 25% and z = 65% (Sample 13), the investigated glass possesses the optimum volume density, bending strength , compression strength and modulus, which are 2.572 g/cm 3 , 74.05 MPa, 312.84 MPa and 163.96 GPa, respectively. Compared to sample 13, samples with different compositions have reduced the volume density, lowered the Raman intensity and improved the optical band gap. For the mechanical properties, with decreasing the contents of SiO 2 , the bending strength firstly increases, then decreases and finally shows a relatively small increasing trend. The dependence of compression strength and compression modulus on SiO 2 content shows a similar trend to the bending strength. Moreover, the optical band gap and Raman spectrum of the sample 13 indicate that the number of oxygen bonds in the bridge reach the maximum, which could further confirm a significantly improvement on the mechanical properties.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2026
·
IF 9.2
Xiaohan Chen,Shuyi Chen,Shiyi Chen,Wenguo Xiang
CaO sorption-enhanced biomass gasification (SEBG) enables in situ CO 2 capture and hydrogen production; however, CaO-based materials often suffer from performance loss during repeated operation. In this work, Ce-promoted CaO-based materials were prepared by introducing different secondary promoters (Ni, Al, Fe, Cu, Co, and Cr). The materials were evaluated using pine wood pellets in a laboratory scale fluidized bed reactor with batch biomass feeding and continuous N 2 /steam flow, and each cycle included 10 min gasification followed by 10 min air regeneration. The effects of steam-to-biomass mass ratio (S/B) and gasification temperature were first investigated, and S/B = 0.5 and 750 °C were selected for promoter comparison. At these conditions, Ce incorporation improved H 2 yield retention during repeated gasification and regeneration cycles. Secondary promoters led to different balances between H 2 yield and H 2 yield retention over repeated cycles. Fe10Ca90Ce10 produced the highest H 2 yield of 1098 mL g −1 biomass (64 vol% of the syngas), representing a 31% enhancement relative to Ca90Ce10. Ni10Ca90Ce10 also achieved a high H 2 yield of 912 mL g −1 biomass (66 vol% of the syngas), with only a 5% decrease after ten cycles. Al10Ca90Ce10 and Cr10Ca90Ce10 showed better H 2 yield retention, with the H 2 yield of both samples increasing by approximately 8% relative to the first cycle. These results indicate that Fe is more favorable for maximizing H 2 yield, whereas Ni, Al, and Cr are more favorable for maintaining H 2 yield during repeated operation, providing guidance for selecting secondary promoters in Ce-promoted CaO-based materials for SEBG systems.
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MATERIALS CHEMISTRY AND PHYSICS
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2026
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IF 5.2
Kaiyue Meng,Xiaowen Wu,Lingxue Wang,Jiacheng Jiang,Ligang Zheng,Qianchao Ma,Chenxin Lin,Longfei Gao,Zhenhua Sun,Juntong Huang,Zhaohui Huang
To mitigate the inherent hydration susceptibility of magnesia-calcia refractories and overcome the restrictions of hydration reactions on their popularization and practical application, a facile impregnation method was adopted to fabricate a self-assembled superhydrophobic coating on the surface of MgO–CaO clinker aggregates. The effects of palmitic acid (PA), titanium dioxide (TiO 2 ), and ethanol (EtOH) content, and impregnation duration on the hydrophobic performance of the superhydrophobic modified solution (SMS) were systematically investigated. The modified MgO–CaO clinker aggregates exhibit excellent superhydrophobicity, with a maximum water contact angle of 158.9° and a low hydration rate of 0.05%. This hydration rate is 64.29% lower than that of the untreated raw aggregates (0.14%). Furthermore, the formation and hydrophobic mechanism of the self-assembled superhydrophobic coating were clarified in depth. The feasible impregnation strategy enables efficient construction of a self-assembled superhydrophobic coating. It provides a promising, scalable, and universal approach for the large-scale preparation of high-performance superhydrophobic and anti-hydration MgO–CaO refractories.
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Thermal Science and Engineering Progress
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2023
·
IF 4.8
Shuai Guo,Guoliang Qi,Jialiang Gao,Deng Zhao,Kaixin Chen,Chenchen Zhao,Xingcan Li,Guangyu Li
Pyrolysis is an effective method for safely disposing of sewage sludge via conversion into a usable energy source. However, municipal sludge has a high protein content, which is a major source of NO x precursors. This study investigated the effect of CaO on NO x precursor formation during glutamate pyrolysis and demonstrated that CaO occupies the carbo x yl site of glutamic acid at 320 °C, which delays its decomposition and promotes the conversion of glutamic acid from a five- to a si x -membered ring. At 400 °C, heterocyclic nitrogen in the tar peaked from 4.87 to 53.87% after adding CaO. As the temperature increases to 480 °C, CaO might promote the conversion of heterocyclic nitrogen into tricyclic piperazine dione in the tar, which subsequently decomposed to produce HCN in large quantities. At 480 °C, CaO contributed to the decrease in pyrrole, pyridine, and quaternary nitrogen in the semi-coke from 24.81%, 12.93%, and 7.43% to 1.91%, 5.97%, and 1.43%, respectively and promoted HCN hydrolysis to form NH 3 . At 480–680 °C, CaO interacted with NH 3 to form CaCN 2 . The product of CaC x N y decomposition—CaC x —captured NH 3 . At high temperatures, CaO inhibited HCN release, which might be related to the reaction between CaO and HCN to form CaC x N y , subsequently reconverted into CaO at temperatures above 680 °C. These findings provide novel insights into the influence of CaO on amino acid pyrolysis to produce NO x precursors and the regulation of NO x precursor production.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Caili Li,Yingjie Li,Chunxiao Zhang,Zhiwei Chu,Yi Fang
CaCO 3 /CaO thermochemical energy storage based on concentrated solar power plant is a promising technology because of its high working temperature and energy storage capacity. Papermaking white mud (PWM) from paper mill is a potential CaO-based precursor due to its high content of CaCO 3 . Herein, a novel Ca 3 B 2 O 6 -modified PWM was synthesized to examine its thermochemical energy storage performance. The influences of the types and dopant amounts of B 2 O 3 precursors on the energy storage capacity of Ca 3 B 2 O 6 -modified PWM were discussed. The stable Ca 3 B 2 O 6 -modified PWM with the mass ratio of CaO to Ca 3 B 2 O 6 = 88:12 exhibits superior energy storage performance and heat transfer property during CaCO 3 /CaO cycles. The effective conversion and energy storage capacity of Ca 3 B 2 O 6 -modified PWM are approximately 0.67 and 2129.6 kJ/kg at 31st cycle, respectively, which are 2.48 and 1.76 times as high as those of PWM and pure CaCO 3 , respectively. The introduction of Ca 3 B 2 O 6 improves the sintering resistance and thermal conductivity of PWM, resulting in higher cyclic stability and lower decomposition temperature of CaCO 3 . Ca 3 B 2 O 6 enhances the basicity and improves the strong basic sites of PWM, which is beneficial for the adsorption of CO 2 , leading to greater CO 2 adsorption capacity. Moreover, Ca 3 B 2 O 6 increases the oxygen vacancy concentration of PWM, which is conducive to the diffusion of O 2– and production of CO 3 2– , further improving energy storage capacity. Hence, Ca 3 B 2 O 6 -modified PWM seems to be a suitable energy storage material for the CaCO 3 /CaO process.
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高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Jiali You,Tao Yang,Dandan Feng,Zhihong Li
Corundum abrasives with plate-like grains were fabricated by a two-step sintering technique using the solution-based process with the addition of the ternary compound additive Na 3 AlF 6 -CaO-SiO 2 . The two-step sintering method showed obvious advantages over conventional sintering methods in promoting sample densification, suppressing grain growth, and homogenizing the microstructure of the corundum abrasives. The sample doped with 2.5 wt% Na 3 AlF 6 and 4 wt% CaO + SiO 2 in the molar ratio of 1:1 possessed a relative density of 99.3%, average grain size of 0.54 µm, and single-particle compressive strength of 49 N. The introduction of seeds reduced the temperature of θ- to α-Al 2 O 3 phase transformation. The relationship between the microstructure and the mechanical properties of the abrasives was also discussed.
研究领域:
材料科学
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陶瓷工程
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高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
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2024
·
IF 3
Zou Yanyan,Pau Dennis,Yi Linlin,Li Yaoqiang,Li Kaiyuan
13X zeolite–calcium oxide (CaO) composite capture agent application in the pyrolysis recovery of polyvinyl chloride (PVC)-based waste cables was investigated in this research to elucidate the agent’s efficiency in capturing chlorine (Cl) and carbon (C) during pyrolysis. The 13X zeolite–CaO mixture is subjected to separate pyrolysis of the PVC-based cable outer sheath in experimental furnaces of simulated solar-powered and thermogravimetry. Subsequently, a range of spectroscopic techniques are employed to quantitatively analyze the gaseous and solid products resulting from the pyrolysis process. Through X-ray fluorescence, total carbon, and other analyses, the research outcomes demonstrated that the capture agent exhibits superior Cl and C capture performance compared to using a single agent for plastic pyrolysis. The yield of Cl element in the solid residue has increased significantly by 130–140% under the presence of optimized composite capture agent. By determining the dynamic changes of gaseous and solid products during the cable outer sheath pyrolysis, the influence of the capture agent on the redistribution and transformation mechanisms of Cl and C elements was identified, and it was found that contaminating volatiles were well immobilized in the solid residue. This research provides a new solution for efficient Cl and C capture in the pyrolysis recovery of waste cables and determines the fixation and transformation mechanisms of Cl and C elements by the composite capture agent, indicating a potential for feasible and sustainable resource utilization of waste cables.
研究领域:
环境科学
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材料科学
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高影响因子
ACS Catalysis
·
2025
·
IF 13.1
Bin Shao,Yongjun Jiang,Su Li,Zhicheng Xie,Zhi-Qiang Wang,Sheng Dai,Honglai Liu,Feng Qian,Jun Hu
High-temperature calcination of carbonate minerals in energy-intensive industrial sectors is one of the greatest contributors to global carbon dioxide (CO2) emissions. The hydrogenation of the most abundant carbonate minerals could potentially mitigate unavoidable CO2 emissions by converting them into value-added products, but progress has been hindered by a limited understanding of this process. Here, we aim to elucidate the underlying mechanism of self-induced direct hydrogenation of carbonates (DHC) to produce metal oxides and syngas at relatively lower temperature without using any catalysts. Various in situ technologies corroboratively illustrate H2 molecules can penetrate into CaCO3 to form multiple CaO/CaCO3 interfaces, resulting in porous CaO. The density functional theory calculations reveal the neighboring O and C sites at the active CaO/CaCO3 interface are responsible for the heterolytic dissociation of H2, leading to the progressively self-induced DHC. An intrinsic microkinetic analysis by tracing the formation rate of the intermediate further verifies its self-induced catalytic characteristics. This subverts the consensus regarding the infeasible self-catalysis of stable ionic crystals. By lowering the temperature to 650 °C, 100% CaCO3 conversion is achieved with a CO selectivity of 91.8% in a packed bed reactor. Inspired by extensive applications of DHC to various carbonates, this innovative idea of treating carbonates as a White Carbon resource may pave a breakthrough pathway toward Carbon Neutrality in the industry.
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JOURNAL OF PHYSICAL CHEMISTRY A
·
2017
·
IF 2.847
Yaming Fan,Yuqun Zhuo,Zhenwu Zhu,Wen Du,Liangliang Li
Zerovalent Se (Se atom and small Se2 molecule) adsorption mechanisms on a CaO surface were studied by both density functional theory (DFT) calculations and adsorption experiments. Nonvalent Se adsorption on the CaO(001) surface was simulated using a slab model. The adsorption energy, adsorption structure, electron density clouds, and electron properties were calculated. Different Se surface coverages were investigated to elucidate the adsorption process. In the experiments, the Se adsorption products were prepared in a U-shaped quartz reactor at 300 °C. The properties were investigated by X-ray photoelectron spectroscopy (XPS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), field emission scanning electron microscopy/energy dispersive X-ray spectroscopy (FE-SEM/EDS), and X-ray diffraction (XRD), respectively. The experimental results match up with the DFT results, which reveal fundamental monochemisorption mechanisms of zerovalent Se on the CaO surface.
研究领域:
表面科学
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环境化学
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计算材料科学
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吸附机理
·
密度泛函理论（DFT）
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DOI
高影响因子
PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2014
·
IF 3.828
Huan Liu,Qiang Zhang,Hongyun Hu,Peng Liu,Xiaowei Hu,Aijun Li,Hong Yao
Thermal disposal of sewage sludge is likely to cause serious nitrogen related environmental pollution since it contains considerable amounts of nitrogen, the species of which are quite different from those in coal. Considering that lime (CaO) is a widely applied chemical conditioner for sewage sludge dewatering, this study investigated the catalytic role of conditioner CaO in nitrogen transformation during sewage sludge pyrolysis in a drop-tube/fixed-bed furnace at 873 K, 1073 K and 1273 K, respectively. Model compounds were also used to further clarify the mechanisms involved. According to the results, conditioner CaO increased the fraction of more stable protein-N as well as amine-N. The solid phase reactions produced CaC x N y , thus enhancing the nitrogen retention in char. Correspondingly, decreased relative ratio of nitrates-N/nitrites-N and oxygenated organics in sludge conditioning contributed to less NO emission. Meanwhile, conditioner CaO promoted the conversion of HCN to NH 3 , as well as the deamination of proteins, amine, and other N-containing compounds in tar and char, leading to increased NH 3 generation. Subsequently, CaC x , the decomposition product of CaC x N y , captured NH 3 , driving down the final production of NH 3 . In addition, Ca(OH) 2 hindered the transformation of nitrile-N in char to HCN, decreasing HCN generation. CaO reacted with HCN, further reducing its releasing amount. CaC x N y derived from different sources decomposed to produce a very large amount of N 2 . These indicate that reusing conditioner CaO is a promising strategy for reducing the productions of NO x precursors efficiently and increasing the formation of non-polluting N 2 dramatically.
研究领域:
环境科学
·
能源与燃料
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高影响因子
Sustainable Energy Technologies and Assessments
·
2026
·
IF 7.4
Hui Li,Yixuan Zhang,Phumlani Fortune Msomi,Yunpu Wang,Xiaoling Ma
CaO-CNT absorbs 92% broad-spectrum light and rapidly produces localized heat. • Photothermal transesterification delivers efficient energy supply to active sites. • Under optimal conditions, 99.22% biodiesel conversion is achieved at 50 °C. • LCA demonstrates low carbon profile with GWP 2.07 kg CO 2 eq·kg −1 and DFF 28.24 MJ·kg −1 . Transesterification for biodiesel production demands external heat supplied through temperature gradient-driven heating, which limits energy efficiency. Photothermal catalysis offers an alternative route, but reported photothermal catalysts for biodiesel transesterification often suffer from narrow-spectrum light harvesting, strict requirements for monochromatic high-power light sources, and inefficient heat delivery to active sites, which severely restrict their practical application. In this study, a CaO-CNT photothermal catalyst was fabricated via wet impregnation coupled with high-temperature calcination to enable in-situ solar-to-heat conversion and boost catalytic activity. Multiple characterization techniques, including TG/DTG, XRD, XPS, SEM, Raman spectroscopy, N 2 adsorption and desorption, UV-Vis-NIR spectroscopy and infrared thermal imager were carried out, and simulated sunlight from a xenon lamp was used for palm oil photothermal transesterification. The CaO-CNT catalyst exhibited 92% light absorption over 300-2500 nm and rapidly increased its surface temperature from ambient temperature to 70.7 °C within 300 s under an irradiation power density of 14.5 W/g. Compared with conventional water-bath heating, photothermal heating catalyzed by CaO-CNT resulted in higher biodiesel conversions, with improvements of 7.71%, 12.48%, and 9.71% at 46 °C, 50 °C, and 54 °C, respectively. The maximum biodiesel conversion of 99.22% was achieved by photothermal-driven heating with a catalyst loading of 6 wt%, a methanol/oil molar ratio of 10, and an irradiation power density of 15.2 W/g for 2.5 h. Findings from life cycle assessment (LCA) established that the global warming potential (GWP) of this process reached 2.07 kg CO 2 eq·kg −1 , with the depletion of fossil fuel (DFF) amounting to 28.24 MJ·kg −1 . Download: Download high-res image (194KB) Download: Download full-size image
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