JOURNAL OF APPLIED POLYMER SCIENCE
·
2017
·Vol. 135
·期 10
·45940
·
IF 1.86
Mei Wang,Jianchun Jiang,Jianling Xia,Shouhai Li,Mei Li
Phosphate ester groups containing ricinoleic acid-based Ca/Zn (LPPRA-Ca and LPPRA-Zn) stabilizer was successfully synthesized from ricinoleic acid (RA) and used as thermal stabilizers for poly(vinyl chloride) (PVC). These thermal stabilizers were characterized by Fourier transform infrared spectrometry, 1 H nuclear magnetic resonance, and inductively-coupled plasma atomic emission spectroscopy. The effects of LPPRA-Ca/LPPRA-Zn, CaSt 2 /ZnSt 2 , and other stabilizers on the thermal stability of PVC were studied through Congo Red test, discoloration tests, thermogravimetric analysis (TGA), TGA–infrared, and TGA–mass spectrometry. The thermal stability tests show that LPPRA-Ca/LPPRA-Zn displays the best initial color stability and long-term thermal stability for PVC. The superior performance is attributed to the synergistic effect of LPPRA-Ca and LPPRA-Zn. Moreover, a lower Zinc content of LPPRA-Zn in PVC helps to decrease the “zipper dehydrochlorination” of the product, which contributes to a better initial thermal stability. Except for the better stabilization performance, LPPRA-Ca/LPPRA-Zn also displays better plasticization performance for PVC compared with other stabilizers. A possible stabilizing mechanism of PVC/LPPRA-Ca/LPPRA-Zn system was presented. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45940.
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2022
·
IF 3.662
Yanfei Jia,Jianwen Wei,Yuan Yuan,Xiaobin zhou,Linlin Geng,Lei Liao
Using KIT-6 as the silica source, a series of Li 4 SiO 4 adsorbents (KIT-6-Li 4 SiO 4 ) were synthesized by impregnation precipitation method for high temperature CO 2 capture. Then, the KIT-6-Li 4 SiO 4 -800–4 (KL-800–4) material, was selected to analyze the improvement of the adsorption performance by Ca 2+ /Na + eutectic doping modification. These adsorbents were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and low temperature N 2 adsorption/desorption, and the CO 2 adsorption capacity of them was explored. At 600 °C and under 15 vol% CO 2 , KL-Ca0.03 and KL-Na0.06 sorbents resulted in a CO 2 uptake of 29.17 wt% and 35.35 wt% (close to the theoretical maximum), respectively，which are much higher than that of KL-800–4 (14.73 wt%). After 10 adsorption/desorption cycles, the adsorption capacity of KL-Na0.06 increased by 1.35 wt%. We found that KL-Na0.06 has more advantages compared with traditional lithium orthosilicate and undoped adsorbents, including lower energy consumption, higher CO 2 adsorption capacity and better cycling ability. Finally, the double exponential model had a high degree of fit for the adsorption of CO 2 by Li 4 SiO 4 .
✓ 已验证
产品关联
DOI
高影响因子
APPLIED ENERGY
·
2022
·
IF 11.446
Xianyao Yan,Yingjie Li,Chaoying Sun,Chunxiao Zhang,Liguo Yang,Xiaoxu Fan,Leizhe Chu
The sorption-enhanced steam gasification of biomass (SESGB) using CaO-based materials is considered as a promising method for H 2 production. Ca-Al-Ce material has been reported as a good bi-functional material in SESGB process. Red mud is a solid waste in aluminium industry with large yield, which is rich in Fe 2 O 3 . In this work, a red mud-doped Ca-Al-Ce bi-functional material was prepared by wet-mechanical mixing method for H 2 production from SESGB. The CO 2 capture, H 2 production, and tar reduction performances during SESGB process using the red mud-doped Ca-Al-Ce bi-functional material were studied. The results show that the optimum addition amount of red mud in the bi-functional material is 5 wt%. After 20 SESGB cycles, the H 2 concentration using the red mud-doped Ca-Al-Ce material achieves 65.1 vol%, which is 82.4% higher than that using Ca-Al-Ce material. Besides, with the addition of red mud in the bi-functional material, the tar, residue char yields and CO 2 concentration decrease by 25.2%, 8.6% and 52.2%, respectively. Fe 2 O 3 in the red mud reacts with CaO to form Ca 2 Fe 2 O 5 in the 1st cycle, and Ca 2 Fe 2 O 5 is stable during 20 cycles, which is beneficial for the generation of oxygen vacancy. The oxidation states of Fe species in the material increase with the number of SESGB cycles, thus the catalytic effects on water gas shift reaction and tar reduction are promoted. The red mud addition is the key factor that results in high H 2 production, CO 2 capture and tar reduction performances, so the red mud-doped Ca-Al-Ce material appears promising for SESGB.
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Jianjie Chen,Yuming Tu,Gaoyan Shao,Fan Zhang,Zhiyong Zhou,Shichao Tian,Zhongqi Ren
A novel Calcium-loaded catalyst (Ca-C/Al 2 O 3 ) was prepared with a facile impregnation method, using polyethyleneimine (PEI)-polydopamine (PDA) as a coating agent and Al 2 O 3 as supporter. The prepared Ca-C/Al 2 O 3 catalyst showed a higher treatment performance for high salt organic wastewater, and removal rate of chemical oxygen demand (COD) was enhanced from 32.5% to 64.4% comparing with single ozonation. Besides, it also showed a good catalytic performance comparing with other catalysts reported in different literature. Catechol groups and reactive amine groups in the PEI-PDA coating worked as anchoring points for metal ions, facilitating the formation of dispersed calcium sites (Ca-O and Ca-N). Calcium sites and different types of nitrogen (graphite nitrogen, pyrrolic nitrogen, and pyridinic nitrogen) were identified as the active sites for the catalytic reaction. The analysis of electron paramagnetic resonance (EPR) and radical quenching tests revealed that hydroxyl radical (•OH) and singlet oxygen ( 1 O 2 ) were the reactive oxygen species (ROS) for treatment of high salt organic wastewater. According to the above results, the prepared Ca-C/Al 2 O 3 catalysts showed a good catalytic permanence and used for advanced treatment of high salt organic wastewater.
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2022
·Vol. 9
·期 20
·5188-5194
·
IF 7.779
Zhi Fang,Chun-Li Hu,Wen-Tong Chen,Jiang-Gao Mao
Exploration of short-wave ultraviolet beryllium-free Sr2Be2B2O7-type borates is of great significance to the development of short-wave ultraviolet lasers. As a structural analogy to BeO4, the ZnO4 unit has been demonstrated as a facile building unit for the design of beryllium-free borates with balanced overall performance. Nevertheless, despite the discovery of numerous zincoborates, no Sr2Be2B2O7-type zincoborates with characteristic bilayer structures constituted by ZnO4 and BO3 units have been found, highlighting the great challenge in the design and syntheses of Sr2Be2B2O7-type zincoborates. Herein, two new beryllium-free Sr2Be2B2O7-type zincoborates, namely, Na3AEZn2B3O9 (AE = Mg and Ca), were rationally obtained by a chemical cosubstitution design strategy. With the cosubstitution of Sr2+, Be2+ and out-of-plane bridging O2− of {Sr[Be2(BO3)2O]}∞2− bilayers of Sr2Be2B2O7, Na3AEZn2B3O9 (AE = Mg and Ca) featuring a new Sr2Be2B2O7-type bilayer structure of {Na3[Zn2(BO3)2(BO3)]}∞2− were successfully isolated, indicating the feasibility of chemical cosubstitution for the design of Sr2Be2B2O7-type zincoborates. In particular, Na3CaZn2B3O9 exhibits a wide band gap of 4.43 eV, a moderate birefringence of 0.045@1064 nm and a high melting point of 843 °C, being favorable to practical applications.
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2021
·
IF 4.539
Ying Zhang,Jun Li,Fan Zhang,Xiao Li,Baige Yuan,Manman Xia,Peng Zhao,Ruyan Lei
Doping elements play an important role in improving the conductivity of Li 4 Ti 5 O 12 used as anode materials for lithium ion batteries . In this work, nanoparticles of Li 4-X Ca x Ti 5 O 12 (x = 0, 0.03, 0.05 and 0.07) were successfully synthesized through a facile hydrothermal method followed by calcination . The evolution in microstructure as well as electrochemical performance of the modified samples with the doped Ca content were investigated in details. It was found that modified Li 4-x Ca x Ti 5 O 12 (x = 0.05) exhibited the best electrochemical performances in terms of the highest initial specific discharge capacity (158.55 mA h g −1 at 160 mA g -1 ), best cycling stability with a retained specific charge capacity of 104.76 mAh g −1 at 160 mA g -1 after 100 cycles and rating capability with a retained rate of 64.55 %/88.56 % with the current density drastically increased 1600 mA⋅ g −1 and dropped to initial value. The excessive introduction of Ca (x = 0.07) caused the sharp decrease in electrochemical performance due to the formation of inert and insulating CaCO 3 . Li 4-x Ca x Ti 5 O 12 (x = 0.05) also demonstrated a lowest ohmic resistance (2.35 Ω) and charge transfer resistance (95.42 Ω).
✓ 已验证
产品关联
DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2020
·
IF 4.794
Xiaowei Fang,Ze Wang,Wenli Song,Songgeng Li
In this paper the aldol condensation of furfural (C5) with acetone (C3) over Ca/ZSM-5 was studied with lower dosages of water and acetone as compared to previous studies. It was observed that the formation of CaO over the catalyst is critical to catalyst activity and that the reaction may not occur without water. Although higher quantity of water was favorable for the formation of 4-(2-Furyl)-3-buten-2-one (C8), it was inhibitive for the formation of 1,5-bis-(2-furanyl)-1,4-pentadien-3-one (C13). Highest yields of C8 (38.4 mol%) and C13 (60.2 mol%) were obtained with C3-to-C5 mole ratio of 0.8:1, and water content of 29.7 wt%. The deactivated catalyst was further regenerated by re-loading CaO. An intrinsic kinetic model was established whereby the reaction was first-order dependent on the concentration of each reactant. The formation of 4-(2-furyl)-4‑hydroxy‑butan-2-one (C8-OH), and the C8-OH-to-C8 dehydration were essential steps. The reaction of C8-OH with C5 owned the highest activation energy (41.9 kJ/mol), this step was more sensitive to reaction temperature than those of other steps.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2020
·Vol. 27
·期 5
·1-11
·
IF 2.426
Pan Zheng,Lv Yukai,Chen Yulong,Qian Xin
Waterproofing layers play a pivotal role in tunnel engineering and building basements. Magnesium acrylate (CA-Mg 2 ) shot-membrane waterproofing materials- commonly used as a waterproof layer- is a type of hydrogel. Poly(vinyl alcohol) (PVA) solution subjected to freezing/thawing treatment has been added to a CA-Mg 2 monomer, resulting in the formation of a CA-Mg 2 /PVA interpenetrating polymer network (IPN) hydrogel which can produced by a redox initiation system. This new IPN hydrogel contains not only a CA-Mg 2 network formed with Mg 2+ coordination bonds, but also a PVA network created by hydrogen bonding between hydroxyl groups. In comparison to CA-Mg 2 hydrogels, the fracture stress of the CA-Mg 2 /PVA hydrogel increased from 0.45 MPa to 0.72 MPa, elongation from 602% to 854%, and the self-healing efficiency of the IPN hydrogel reached 99.9% over 3 h. A new shot-membrane waterproofing materials based on the CA-Mg 2 /PVA hydrogel was prepared and its fracture stress was 1.44 MPa, and self-healing efficiency 80%, at 3 h. In addition, damage to the hydrogel could be repaired repeatedly.
✓ 已验证
产品关联
DOI
高影响因子
CEMENT AND CONCRETE RESEARCH
·
2024
·
IF 10.9
Binmeng Chen,Xu Fang,Yuyang Zhao,Zongjin Li
In recycling and reusing construction waste, carbonation of recycled concrete fine (RCF) has been successfully applied to produce value-added products, such as silica nanoparticles, via the breaking of calcium silicate hydrate (C-S-H) structure and condensation of silicate chains. However, the intricacies of carbonation of RCF with varying calcium to silicon (C/S) ratios and their implications on the size of generated silica nanoparticles remain unknown. In this work, we developed an optimized carbonation method at high water to solid ratio to fabricate silica nanoparticles from C-S-H with different C/S ratios. The particle size of silica nanoparticles was found to gradually decrease with the increased C/S ratio of C-S-H. Since as C/S ratio increased, silicate in Q 3 state shifted to Q 1 state and the silicate chain became shorter, shifting from long-range, disordered to short-range, ordered. As the disordered self-seeding growth of long silicate chains derived from C-S-H continued, the Si-O-Si network of silica nanoparticles became chaotic, leaving more unreacted Si-OH on its surface. On the contrary, the short silicate chains displayed higher possibility of condensation, making nanoparticles with a smaller diameter.
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2016
·
IF 4.219
Huizhen Zheng,Meng Gao,Ying Ren,Ruyun Lou,Hongguo Xie,Weiting Yu,Xiudong Liu,Xiaojun Ma
A pH-responsive carrier based on an ethylenediaminetetraacetic-calcium-alginate (EDTA-Ca-Alg) system was developed by controlling the release of Ca 2+ . The system remained in the solution state at neutral pH since EDTA completely chelated the Ca 2+ . In contrast, a hydrogel immediately formed when the pH was below 4.0, which triggered the in situ release of Ca 2+ from the EDTA-Ca compound and led to alginate-Ca binding. Taking advantage of the pH sensitivity, we prepared hydrogel microspheres with uniform size to entrap Lactobacillus rhamnosus ATCC 53103 through emulsification. In an acidic environment, the hydrogel structure remained compact with negligible pores to protect L. rhamnosus ATCC 53103. However, in a neutral intestinal environment, the hydrogel structure gradually disassembled because of the Ca 2+ release from the hydrogel, which caused cell release. Therefore, a pH-responsive carrier was developed for the protection and the controlled release of cells in gastrointestinal tract, thus providing potential for oral delivery of probiotics.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
GREEN CHEMISTRY
·
2017
·Vol. 19
·期 21
·5103-5113
·
IF 9.125
Ying Duan,Min Zheng,Dongmi Li,Dongsheng Deng,Lu-Fang Ma,Yanliang Yang
The catalytic conversion of HMF to 2-hydroxy-3-methyl-2-cyclopenten-1-one (MCP), which is a valuable edible essence that has traditionally been obtained from adipic acid, was achieved with an isolated yield of 58%. This procedure comprised two steps: the hydrogenation of 5-hydroxymethylfurfural (HMF) to 1-hydroxy-2,5-hexanedione (HHD) in water on Pd/Nb2O5 catalysts and then the isomerization of HHD to MCP in the presence of a base. The Nb2O5 supports, which were acidic, were characterized by FTIR, XRD and NH3-TPD. The supported Pd/Nb2O5 catalysts, in which Pd was highly dispersed, were synthesized employing cyclohexene as a reductant and were characterized by XRD, TEM, ICP-AES, XPS, EDX and CO pulse chemisorption. The high conversion of HMF was attributed to the high dispersion of Pd, and the acidity of the supports led to high selectivity for HHD. The conversion of HHD to MCP was an intramolecular aldol condensation reaction, and the protonic solvent favored this reaction. Ca–Al was proved to be an effective solid base for the conversion of HHD to MCP in water.
✓ 已验证
产品关联
DOI
高影响因子
Asia-Pacific Journal of Chemical Engineering
·
2012
·Vol. 8
·期 4
·567-577
·
IF 0.758
Ying Gu,Xiaowei Liu,Bo Zhao,Wenqiang Liu,Minghou Xu
Nitrogen species distribution during coal pyrolysis with Ca addition in N 2 , CO 2 and Ar was studied at 1000 °C using a horizontal tube furnace. In particular, the effect of Ca on the distribution of nitrogen species in N 2 and CO 2 atmospheres, which were closer to pyrolysis processes of conversional air and oxy-fuel combustion in comparison with inert Ar environment, was investigated for the first time in this work. It was found that Ca has a great effect on nitrogen species distribution during both coal and demineralized coal pyrolysis; on the other hand, CO 2 causes the formation of NO. Demineralization increases the formation of HCN and char nitrogen, but there is little effect on NH 3 formation during pyrolysis in N 2 , in contrast to pyrolysis in Ar atmosphere, which decreases NH 3 formation. A significant reduction in char yield was found after char gasification in CO 2 at 1000 °C. With two different Ca-based additives, i.e., (CH 3 COO) 2 Ca and Ca(OH) 2 , char yield decreases with the increasing amount of Ca additives in both cases. The effect of Ca on HCN and NH 3 formation during pyrolysis depends on both the form of Ca and the amount of addition. In most cases, HCN and NH 3 formation decreases with Ca addition in Ar, but increases in N 2 . Ca addition slightly promotes HCN formation during pyrolysis in CO 2 . There is no NH 3 detected during pyrolysis in CO 2 because of the reaction of NH 3 and CO 2 in the background. In addition, NO concentration decreases sharply with increasing the amount of Ca addition in the atmosphere of CO 2 , which means that Ca has an effect not only on pyrolysis, but also on gasification of char in CO 2 . In most cases, char nitrogen increases with Ca addition in N 2 or Ar. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
✓ 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）