THERMOCHIMICA ACTA
·
2017
·
IF 2.236
Mei Wang,Xianghai Song,Jianchun Jiang,Jianling Xia,Shouhai Li,Mei Li
Hydroxyl and nitrogen rich groups-containing tung-oil-based Ca/Zn (Ca-HTMA-1, Zn-HTMA-1, Ca-HTMA-2 and Zn-HTMA-2) and polyol thermal stabilizers (HTMA-1 and HTMA-2) were successfully synthesized from tung-maleic anhydride (TMA). The thermal stability tests show that CaSt 2 /Zn-HTMA-2/HTMA-2 displays the best thermal stability for poly(vinyl chloride) (PVC). The superior performance is attributed to the synergistic effect of CaSt 2 , Zn-HTMA-2 and HTMA-2, which is originated from the simultaneous introduction of hydroxyl and nitrogen rich groups into the Zn-HTMA-2 and HTMA-2 structures. The nitrogen rich groups can absorb the hydrogen chloride released during the PVC degradation process, which helps to inhibit the “autocatalytic effect” and lead to better long term thermal stability. Besides, hydroxyl groups can form stable chelates with ZnCl 2 to avoid “zinc-burning” during the later PVC degradation. Besides the better stabilization performance, CaSt 2 /Zn-HTMA-2/HTMA-2 also displays comparable plasticization performance for PVC compared with other stabilizers. A possible stabilizing mechanism of PVC/CaSt 2 /Zn-HTMA-2/HTMA-2 system was presented.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Advanced Sustainable Systems
·
2025
·
IF 6.1
Yu Ren,Youhao Zhang,Zizheng Zhou,Yi Fang,Yuzhuo Wang,Yingjie Li
Ca(OH) 2 can be used in CO 2 uptake from the flue gas in fossil-fired power plants. Compared with indirect method where Ca(OH) 2 is first converted into CaO and then uptakes CO 2 , direct CO 2 uptake by Ca(OH) 2 occurs at lower temperature, leading to slighter sintering. However, the direct CO 2 uptake capacity of Ca(OH) 2 should be further enhanced. In this study, Ca(OH) 2 is doped with Mn to improve its direct CO 2 uptake capacity in carbonation-calcination-hydration cycles. The cyclic tests are conducted in a triple fixed-bed reactor. The mechanism of CO 2 adsorbed on Mn-modified Ca(OH) 2 is determined by density functional theory calculations. In the first cycle, Mn-modified sorbents acquire highest carbonation conversion at 400 °C, which is 40 °C lower than Ca(OH) 2 . The modified Ca(OH) 2 with Ca/Mn molar ratio of 100:0.75 exhibits the best performance, and its carbonation conversions reach 0.76 and 0.59 in the 1st and 20th cycles, respectively, which are 28% and 18% higher than those of Ca(OH) 2 . Furthermore, carbonation conversion of this Mn-modified Ca(OH) 2 decreases by within 1.00% from cycle 5 to 20. Mn addition boots oxygen vacancy, increases the surface area and pore volume, and reduces the energy barrier for carbonation of Ca(OH) 2 . Mn-modified Ca(OH) 2 as CO 2 sorbent appears promising.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Storage
·
2022
·
IF 8.907
Zhiguo Bian,Yingjie Li,Feifei Wang,Yi Fang,Jianli Zhao,Jianhui Qi
CaO/Ca(OH) 2 heat storage system is one of the most promising candidates for large-scale thermochemical heat storage at temperature of 300–600 °C. In this work, the CaO/Ca(OH) 2 heat storage performances of the Ce- and Mn-doped CaO were investigated and the mechanisms of promoting hydration by Ce and Mn doping were determined via density functional theory (DFT) calculations. The Mn-doped CaO exhibits the higher hydration conversion than CaO and Ce-doped CaO. The structural parameters, partial density of states, electron differential densities and energy barriers during hydration stage on the CaO, Ce- and Mn-doped CaO surfaces were compared to clarify the effects of Ce and Mn on hydration of CaO. The results show the detailed hydration reaction pathways on the CaO, Ce- and Mn-doped CaO surfaces. During the H 2 O adsorption stage, H 2 O on the Ce-doped CaO surface approaches the Ca atom first, while H 2 O on the Mn-doped CaO surface approaches the O s atom first. The adsorption energy for Ce- and Mn-doped CaO are −1.612 and −0.896 eV, respectively, which are higher than that for CaO. The doping of Ce and Mn accelerates the H 2 O adsorption on the CaO surface. The Mn doping causes the 84.3 % reduction in the energy barrier for hydration of CaO and the reduction by Mn doping is larger than that by Ce doping. Thus, Mn-doped CaO exhibits the higher hydration reactivity and hydration conversion than CaO and Ce-doped CaO. The DFT calculations determined the promotion mechanism of Ce and Mn doping on the hydration of CaO in CaO/Ca(OH) 2 heat storage.
研究领域:
材料科学
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热能储存
·
计算化学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Jiawen Wu,Xiaonan Sun,Junting Wu,Xue Yu
This study proposes a green and simple strategy for efficiently removing heavy metals from wastewater by activating biochar with eggshell and in-situ generating CaO/Ca(OH) 2 . Characterization results revealed that the composite carbon material (BCEg15) successfully incorporated CaO/Ca(OH) 2 active sites compared to the raw biochar (BC). Additionally, eggshell activation increased the specific surface area and pore volume of BCEg15 by 4.36 and 6.80 times, respectively, compared to BC. These structural enhancements increased the maximum adsorption capacity of BCEg15 for Pb 2+ and Cd 2+ by 20.68 and 42 times, respectively, compared to BC. Importantly, the loading of CaO and Ca(OH) 2 significantly enhanced the ion exchange and mineral precipitation capacities of the biochar. For instance, compared to BC, the adsorption capacities of BCEg15 attributed to ion exchange (Q e ) for Pb 2+ and Cd 2+ rose by 403.12 mg/g and 197.65 mg/g, respectively, while the adsorption capacities attributed to mineral precipitation (Q p ) increased by 19.60 times and 45.20 times, respectively. BCEg15 demonstrated excellent reusability, maintaining adsorption capacities of 461.18 mg/g for Pb 2+ and 265.26 mg/g for Cd 2+ after five cycles. Additionally, BCEg15 outperformed commercial activated carbon in treating heavy metals from desulfurization wastewater from coal-fired power plants, achieving a removal efficiency of 99.98 % compared to 48.22 %. The primary mechanisms by which BCEg15 removes Pb 2+ and Cd 2+ were identified as ion exchange, mineral precipitation, complexation with oxygen-containing functional groups, and interactions with π electrons. Density functional theory (DFT) was utilized to delve deeper into the microscopic mechanisms of adsorption. The findings showed that the O-top site of CaO exhibited the greatest stability for heavy metal adsorption. Electron density difference maps and partial density of states (PDOS) results revealed a denser electron cloud and greater orbital overlap between CaO and Pb 2+ compared to Cd 2+ , suggesting a higher affinity and adsorption capacity for Pb 2+ , consistent with the experimental findings. This study presents an effective method for preparing adsorbents capable of removing Pb 2+ and Cd 2+ from wastewater and offers theoretical insights into the adsorption mechanisms of metal oxide-incorporated biochar.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Materials Research Express
·
2022
·Vol. 9
·期 6
·065505
·
IF 2.025
Qinghong You,Xiulian Yin,Jun Wang,Chunhua Dai
A recyclable heterogeneous KF/Ca-Mg-Al-O catalyst was prepared by co-precipitation and calcination processes. The characteristics of the catalyst were investigated using FTIR, XRD, TG-DTG and SEM. Response surface methodology was utilized to obtain the best most extreme biodiesel production yield. The ideal biodiesel production conditions were: the amount of catalyst was 3 wt%; the reaction temperature was 65 °C; the alcohol oil molar ratio 9.8:1, the reaction time was 3.5 h. Under these amended conditions, the average biodiesel yield was 95.19%, which is well in close concurrence with the worth anticipated by the model. The repeatability of catalysts was studied. After using the catalyst seven times, the catalytic efficiency was only reduced by 2.7%. These results indicate that the catalyst has good catalytic efficiency and is recyclable.
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 13
·50099
·
IF 2.52
Dan Zhang,Dehai Meng,Zhongying Ma,Zhihao Zhang,Haozhe Ning,Yuhua Wang
To optimize the poor thermal stability and flammable of polyvinyl alcohol (PVA), a novel environmental-friendly organic–inorganic hybrid flame retardant Ca(H 2 PO 4 ) 2 @HCCP was successfully designed and synthesized via surface treatment technology and used to advance the flame retardancy of PVA. The thermogravimetric analysis implied that Ca(H 2 PO 4 ) 2 @HCCP can enhance significantly the thermal stability and char forming ability of PVA. Combustion results demonstrate that Ca(H 2 PO 4 ) 2 @HCCP could effectively suppress the melt dripping of PVA in the process of combustion. The presence of Ca(H 2 PO 4 ) 2 @HCCP can sharply reduce peak heat release rate and the total heat release up to 75% and 22.9%, respectively, in the microscale combustion calorimeter measurement. The results manifested that Ca(H 2 PO 4 ) 2 @HCCP could endow PVA with superior flame retardancy. Moreover, char residues analysis explained the flame retardant mechanism in condensed and gas phase, which is mainly attributed to the strong catalytic char formation, free radical trapping, and gas barrier effect. Therefore, the green flame retardant has great application s prospect in fire safety.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Frontiers in Chemistry
·
2022
·
IF 5.545
Wang Huan,Fan Yanmiao,Yang Qiaoli,Sun Xiaoyu,Liu Hao,Chen Wei,Aziz Ayesha,Wang Shenqi
Redox activity is an important indicator for evaluating electrochemical biosensors. In this work, we have successfully polymerized indole-5-carboxylic acid into poly-5-carboxyindole nanomaterials (PI-5-CA), using its superior redox activity, and introduced carboxylated single-walled carbon nanotubes (C-SWCNTs) to synthesize a composite material. Finally, a synthesized composite material was used for the modification of the glass carbon electrode to fabricate the PI-5-CA/C-SWCNTs/GCE-based immunosensor and was successfully applied for the sensitive detection of E. coli O157:H7. The fabricated immunosensor exhibited an outstanding electrocatalytic activity toward the detection of E. coli O157:H7 with a remarkably lowest limit of detection (2.5 CFU/ml, LOD = 3 SD/k, n = 3) and has a wide linear range from 2.98×101 to 2.98×107 CFU/ml. Inspired from the excellent results, the fabricated electrode was applied for the detection of bacteria from real samples (water samples) with a good recovery rate (98.13–107.69%) as well as an excellent stability and specificity. Owing to its simple preparation, excellent performance, and detection time within 30 min, our proposed immunosensor will open a new horizon in different fields for the sensitive detection of bacteria from real samples.
研究领域:
生物传感
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材料科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2024
·
IF 5.3
Qiang Zhang,Xu Li,Jinxiang Dong
Despite significant breakthroughs that have been made in the application performance of traditionally distributed Guerbet alcohol ethoxylates (GAEO), research on the characteristics of their narrow distribution products remains relatively limited. Herein, a series of hydrophilic and hydrophobic nonionic surfactants have been synthesized via the ethoxylation of 2-butyl-octanol with ethylene oxide. Ca(OAc) 2 was employed as a narrow distribution (NRD) catalyst, while KOH served as a broad distribution (BRD) catalyst. The synthesized products were characterized using Fourier-transform infrared (FT-IR), 1 H and 13 C nuclear magnetic resonance ( 1 H, 13 C NMR) spectroscopy. In addition, a comprehensive assessment of the physicochemical and surface properties of the NRD GAEO surfactants was conducted through systematic investigations. The results were then compared to conventionally distributed GAEO surfactants. The study has demonstrated that NRD GAEO surfactants exhibited lower critical micelle concentration (CMC) values, which have the higher efficiency of the surfactant application. In addition, the NRD products have superior wettability performance, reduced foaming capacity in foam properties, and improved rapid defoaming capacities. In regarding their other properties, they closely mirrored the performance of BRD products. These findings will contribute to a comprehensive understanding of the properties of NRD ethoxylates and have substantial practical implications in optimizing personal care and household cleaning products.
研究领域:
化学
·
材料科学
·
表面活性剂技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NANOBIOTECHNOLOGY
·
2024
·Vol. 22
·期 1
·1-16
·
IF 10.6
Li Qian,Liu Chenguang,Xing Dongming
On-demand dissolution of hydrogels has shown much potential in easy and pain-free removal of wound dressings. This work firstly describes a type of carbon dots (CDs) for dissolving Ca-alginate hydrogel via site-specific mineralization method. The CDs were characterized by two features, which included presence of primary/secondary amine groups and generation of calcium crystals with Ca 2+ . Especially, the amount of primary/secondary amine groups on CDs played key role in determining whether hydrogel could be dissolved. When there were sufficient primary/secondary amine groups, the mineralization occurred on CDs rather than alginates due to the hydrogen bond between primary/secondary amine and carboxyl of alginates. Thereby, this promoted the gel-sol transition through Ca 2+ capture from the hydrogels. Moreover, antibacterial test revealed Ca 2+ capture from cell walls, while in vivo test revealed hypoxia relief due to porous structures of the renewed hydrogels. Overall, CDs with sufficient primary/secondary amine groups could dissolve Ca-alginate hydrogel through site-specific mineralization method, accompanying by additional functions of antibacterial and hypoxia relief. Graphical Abstract
研究领域:
材料科学
·
生物医学工程
·
纳米技术
·
伤口愈合
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Zhuowen Wang,Haijun Chen,Shiyi Zhao,Dapeng Liang,Deming Dong,Zhiyong Guo,Jiao Qu,Haiyang Liu,Xiuyi Hua
The extensive use of antibiotics poses a significant risk to human health, and electrocatalysis has demonstrated effectiveness in treating antibiotic contamination. This study details the synthesis of MnO 2 /Pd(OAC) 2 @CA particle electrodes using a straightforward one-step sol–gel method and the development of a three-dimensional electrocatalytic reactor (3DER) to remove antibiotics from water. Under optimal conditions (1.5 g/L MnO 2 /0.3%Pd(OAC) 2 , pH 3 and 2.0 V), a degradation of 97.8% of tetracycline hydrochloride (TCH) at a concentration of 15 mg/L is achieved within 80 min. The rate constant in the 3DER ( k = 0.0389) is 9.26 times greater than that in a two-dimensional electrocatalytic reactor (2DER) ( k = 0.0043). After ten cycles of treatment, the degradation rate of TCH remains at 86.4%. Furthermore, under optimal conditions, the energy consumption of the 3DER is significantly lower than that reported in other studies, with an EEO value of only 0.033 kWh/m 3 . Radical scavenger experiments and electron paramagnetic resonance (EPR) studies identify the free radicals involved, including •OH, SO 4 • – , H*, and •O 2 – . Theoretical calculations and toxicity assessment reveal a general reduction in the toxicity of the intermediate products formed during the electrocatalytic degradation of TCH. In summary, the MnO 2 /Pd(OAC) 2 @CA particle electrodes exhibit high electrocatalytic degradation efficiency, excellent recyclability and reusability. The 3DER constructed using particle electrodes demonstrates broad applicability and environmental friendliness, providing a novel solution for remediating antibiotic-contaminated water.
研究领域:
环境科学
·
电化学工程
·
抗生素污染治理
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2024
·
IF 5.2
Xiaoyu Zhang,Xin Xu,Xinyu Wang,Huibin Liu,Mingli Fu
The improvement of catalytic efficiency is of great significance to the removal of volatile organic compounds (VOCs), a class of key air pollutants leading to ground-level ozone pollution. Herein, a series of micro-spherical Ca-Mn mixed oxides (Ca x Mn y O z ), namely CaMn 3 O 6 , Ca 2 Mn 3 O 8 and CaMnO 3 , were prepared by a two-step precipitation method, and defects were constructed on which by selective dissolution to enhance the low-temperature catalytic performance in the oxidation of propane (C 3 H 8 ) as a representative short-chain alkane VOCs. The synthesized Ca x Mn y O z oxides demonstrated drastically different response to the dissolution modification initiated by acid treatment. Specifically, after acid dissolution, while CaMn 3 O 6 and Ca 2 Mn 3 O 8 maintained largely their original structures, the perovskite-type CaMnO 3 underwent lattice rearrangement and was transformed into γ-MnO 2 -like product with only a tiny amount of Ca. In C 3 H 8 oxidation, the catalytic performance of CaMnO 3 was significantly improved after selective dissolution, as indicated by a significant decrease of T 90 , i.e. the temperature to achieve 90% C 3 H 8 conversion, from 455 °C to 240 °C. Mechanistic investigation by in-depth X-ray photoelectron spectroscopy studies revealed that selective dissolution led to higher Mn 4+ concentrations and more oxygen vacancies on the oxide surfaces, thus facilitated electron transfer and O 2 activation in C 3 H 8 oxidation reactions. This study paves a new path for the design of cost-effective oxide catalysts toward the abatement of short-chain alkane VOCs.
研究领域:
催化
·
环境科学
·
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Zheng Zhang,Xiao Du,Qiang Wang,Fengfeng Gao,Tongtong Jin,Xiaogang Hao,Pengfei Ma,Jun Li,Guoqing Guan
A scalable three-dimensional (3D) porous composite electroactive film consisting of λ-MnO 2 , reduced graphene oxide (rGO) and calcium alginate (Ca-alg) was successfully fabricated and employed for the selective extraction of Li + ions with low concentration via an electrochemically switched ion exchange (ESIX) technology. The Li + ion adsorption capacity of the obtained λ-MnO 2 /rGO/Ca-alg composite electroactive film reached as high as 32.7 mg g −1 and more than 90% of its equilibrium adsorption capacity was achieved in 1 h. The λ-MnO 2 /rGO/Ca-alg composite electroactive film displayed evident selectivity towards Li + ions. The separation factors for Li + /Na + and Li + /Mg 2+ reached 1040.57 and 358.96, respectively, while tested in simulated brine. The composite film also showed superior electrochemical stability, and the normalized ion exchange capacity retained at 98.3% of its initial value even after 100 successive cycles. The excellent Li + ion recovery performance of the obtained composite film should be attributed to its low ion transfer resistance owing to the porous network structure and the potential-responsive ion-pumping effect in the ESIX process. In addition, a large-scale of such a composite electroactive film could be effectively fabricated by controlling the spreading area of the mixed solution consisting of λ-MnO 2 , rGO and alginate binder. It is expected that such a scalable 3D porous composite film could be a promising alternative for the recovery of lithium ions from salt lake brine.
研究领域:
材料科学
·
环境科学
·
电化学工程
✓ 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）