INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2017
·Vol. 42
·期 33
·21167-21176
·
IF 3.582
Weizi Cai,Jiang Liu,Fangyong Yu,Qian Zhou,Yapeng Zhang,Xiaoqiang Wang,Meilin Liu,Meng Ni
Ca-loaded activated carbon is developed as fuel for direct carbon solid oxide fuel cells (DC-SOFCs), operating without any carrier gas and liquid medium. Ca is loaded on activated carbon through impregnation technique in the form of CaO, which exhibits excellent catalytic activity and significantly promotes the output performance of DC-SOFCs. DC-SOFCs fueled by activated carbon with different Ca loading content (0, 1, 3, 5 and 7 wt. %) are tested and the performances are compared with the DC-SOFC running on the conventional Fe-loaded activated carbon. It is found that the performance of the DC-SOFC with 5 wt. % (373 mW cm −2 ) and 7 wt. % (378 mW cm −2 ) Ca-loaded activated carbon is significantly higher than that of the cells operated on 5 wt. % Fe-loaded activated carbon, 1 wt. % and 3 wt. % Ca-loaded activated carbon. The discharging time and fuel utilization of the DC-SOFC with 5 wt. % Ca-loaded activated carbon are also the optimal ones among all the cells. The microstructure, element distribution and carbon conversion rate of the Ca-loaded carbon, the impedance spectra of the corresponding DC-SOFCs are measured. The reasons for the reduced fuel utilization of 7 wt. % Ca-loaded carbon fuel are analyzed and the advantage of Ca-loaded carbon for DC-SOFCs is demonstrated in detail.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2018
·
IF 11.698
Shunhang Wei,Guan Zhang,Xiaoxiang Xu
Despite a strong visible light absorbance as far as 660 nm, BaTaO 2 N generally exhibits a poor photocatalytic activity for water splitting under ordinary conditions. High levels of defects as well as photocatalytic self-decomposition are likely the major causes for this incommensuration. In this work, we have modified BaTaO 2 N by introducing Ca to the structure, i.e. BaCa x/3 Ta 1-x/3 O 2+y N 1-y (0 ≤ x, y ≤ 1). A number of important properties such as band gap, defects levels and nitrogen content can be tuned by varying the amounts of Ca in the structure. In particular, defects such as Ta 4+ species can be effectively suppressed by Ca incorporation. More importantly, photocatalytic activity for water oxidation has been significantly enhanced and stability against photocatalytic self-decomposition has also been largely improved in Ca modified BaTaO 2 N. An apparent quantum efficiency as high as ∼ 2.1% at 420 ± 20 nm has been achieved and stands as the highest AQE for BaTaO 2 N reported to date. Photoelectrochemical (PEC) analysis reveals a much higher photocurrent in Ca modified BaTaO 2 N and identifies the role of cocatalyst CoO z in reducing charge transfer resistance for water oxidation reactions. Open-circuit voltage decay (OCVD) measurements further confirm the improved charge separation conditions in Ca modified BaTaO 2 N and functions of cocatalyst CoO z in collecting and storing photo-generated holes. The optimal loading point for cocatalyst CoO z corresponds to the one that gives the highest capacity for hole storage.
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POLYMER
·
2022
·
IF 4.432
Hui Wang,Chongrui Zhang,Lusha Jiang,Shan Tong,Yu-Chao Li,Hefu Pu,Qiang Zhao
Calcium bentonites (CaB), rich in European and Asian countries, are potential barrier materials for landfill leachate containment. However, CaB has to be converted into sodium bentonite (NaB) by Na-activation so as to facilitate intercalation modification. In this study, salt-resistant poly(acrylic acid-N, N-diethyl acrylamide) [P(AA-DEA)] was designed to intercalate and graft CaB by in situ polymerization without prior Na-activation. By this design, acrylic acid monomers were first adsorbed into interlayers of Ca-montmorillonite (Ca-MT) through the electrostatic complexation with Ca 2+ , dislodging Ca 2+ from montmorillonite surfaces. Then, ammonium ions of N, N-diethyl acrylamide were adsorbed into Ca-MT interlayers. Swelling index of the obtained CaB/P(AA-DEA) nanocomposite in aggressive coal combustion product (CCP) leachate is 15.8 mL/2g, which is as high as 3.4 times that of CaB. CaB/P(AA-DEA)-based geosynthetic clay liners (GCLs) exhibit very low hydraulic conductivity (1.6✕10 −12 m/s) to CCP leachate, which is as low as 3.3% that of the U.S. standard requirement and ∼4 orders of magnitude lower than that of CaB-based GCL. Polymer elution of CaB/P(AA-DEA)-8% in CCP leachate is as low as 1.9% that of the dry mixed samples.
研究领域:
环境工程
·
材料科学
·
土木工程
·
高分子化学
·
地质屏障材料
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高影响因子
MATERIALS SCIENCE FORUM
·
2016
·
IF 0
Xiu Ju Wang,Xin Lian Shi,Shu Fang Hou,Jian Hua Yang,Kai Li Zhou,Zhong Peng Wang,Li Guo Wang
In this paper, a novel nanocomposite forward osmosis membrane (nTiO2-CTA/CA) was fabricated by introducing nanotitaniumdi oxide (nTiO2) into the cellulose triacetate/cellulose acetate (CTA/CA)-based casting solution using phase inversion methods. Casting composite and preparation--nTiO2 content, blend temperature and coagulating bath temperature--were tested for their effects on pure water flux and salt rejection of membranes. Results revealed that the FO membrane prepared under optimized composition showed excellent desalination performance (high water flux = 5.38 L/m2·h and salt rejection > 97 %). Moreover, SEM images showed that addition of nTiO2 resulted in nanocomposite forward osmosis membrane with a smoother surface. The contact angle of the membranes decreased from 76o to 51° with increase nTiO2 concentration from 0% to 0.10%.
研究领域:
膜科学
·
水处理技术
·
材料科学
·
纳米技术
·
环境工程
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DOI
Processes
·
2026
·Vol. 14
·期 8
·1258
·
IF 3.4
Guiping Liao,Hongmei Tang,Jiayan Wu,Quanyun Ye,Yihao Li,Zhongbo Shang,Leiye Sun,Pingxiao Wu
Schwertmannite (Sch) is a widespread iron oxyhydroxysulfate mineral in acid mine drainage (AMD) systems, and its transformation strongly influences the environmental fate of chromium (Cr). However, the role of Ca(II), which is commonly introduced during alkaline neutralization of AMD, in regulating the transformation of Cr(VI)-adsorbed schwertmannite (Cr-Sch) and subsequent Cr redistribution remains insufficiently understood. In this study, transformation experiments were conducted under various pH conditions (3.0, 7.0, and 10.0) to investigate the effects of Ca(II) speciation on mineral transformation and Cr behavior. The results demonstrated that the transformation of Cr-Sch was predominantly pH-dependent. Under acidic conditions, Cr-Sch transformed into goethite via dissolution–recrystallization, resulting in transient Cr release followed by partial refixation. The presence of Ca(II) exerted only a minor influence due to weak interactions between Ca2+and positively charged mineral surfaces. Under alkaline conditions, Cr-Sch preferentially transformed into hematite through dehydroxylation and cation rearrangement, leading to the sustained release of adsorbed Cr(VI). In contrast, Ca(II) predominantly precipitated as CaCO3precipitate (calcite, aragonite, and vaterite) under alkaline conditions, which coated mineral surfaces and inhibited phase transformation and Cr release. These findings reveal that Ca(II) regulates Cr redistribution primarily through pH-dependent speciation and mineral–surface interactions, highlighting coupled geochemical processes governing iron mineral transformation and contaminant mobility in AMD environments. This study provides mechanistic insights for predicting Cr behavior and optimizing alkaline remediation strategies in mining-impacted systems.
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ENERGY & FUELS
·
2024
·
IF 5.2
Jinchen Ma,Yingjie Mi,Fan Wang,Chaohe Zheng,Haodong Huang,Haibo Zhao
In the chemical looping combustion of chlorine-rich biomass or coal, a trace element, chlorine, will cause serious corrosion of oxygen carriers and heat exchange equipment in boilers. To address this issue, we design Ca- and Ba-decorated oxygen carriers to achieve two goals: on one hand, reducing the concentration of chlorine-containing gases by in situ dechlorination; on the other hand, employing protective materials to preferentially bind with gaseous chlorine to safeguard the active components of the oxygen carriers. Carefully designed experiments are conducted under simplified experimental conditions using 50 ppmv HCl-containing CH4 to evaluate the intrinsic characteristics of oxygen carriers in terms of dechlorination efficiency and reactivity. The results demonstrate that both the reaction performance and the chlorine-resistance performance of Ca–Cu and Ba–Cu composite oxygen carriers are significantly improved. This is because (a) Ca and Ba preferentially form chlorides with HCl, effectively shielding the active Cu component of the oxygen carrier from chlorine poisoning and (b) the specific surface area and pores of Ca/Ba-decorated oxygen carriers are increased, which not only strengthens the heterogeneous reaction between oxygen carrier and combustible gas but also improves the chemical looping combustion performance. The Cl-resistant oxygen carriers, Ca–Cu and Ba–Cu, emerge as promising candidates for the chemical looping combustion of fuels with high chlorine content.
研究领域:
能源化学
·
材料科学
·
环境工程
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Wenjia Yang,Wen Cui,Lin Yang,Guo Zhang,Xiaofang Li,Yu Shen,Fan Dong,Yanjuan Sun
Considering that the structural differences could dictate the photocatalytic efficiency, the cubic SrTiO 3 (STO) and tetragonal CaTiO 3 (CTO) were developed to illustrate the structure–activity relationship. The STO with cubic structure demonstrates much higher photocatalytic toluene removal efficiency ( ca. 80.0%) than that of CTO ( ca. 20.0%), which can be ascribed to boosted formation of reactive oxygen species (ROS), increased selectivity of intermediates, and promoted ring-opening and mineralization rate. Combining theoretical simulation and experimental characterization, the results reveal that the O 2 and H 2 O molecules tend to be adsorbed on the cubic STO, which boosts the formation of ROS. Also, highly selective formation of intermediate (benzoic acid) has been realized to accelerate ring-open and mineralization process as evidenced by the smooth conversion of STO as indicated by Gibbs free energy. This work provides new perspectives on the understanding of relationship between intrinsic structure and photocatalytic performance.
研究领域:
材料科学
·
环境科学
·
催化
·
化学工程
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CHEMOSPHERE
·
2023
·
IF 8.8
Yuhang Cao,Xuewei Wu,Biqing Li,Xia Tang,Xueran Lin,Pengfei Li,Hang Chen,Fu Huang,Chaohai Wei,Jian Wei,Guanglei Qiu
Adsorption showed advantages in removing phosphorus (P) at low concentrations. Desirable adsorbents should have sufficiently high adsorption capacity and selectivity . In this study, a Ca–La layered double hydroxide (LDH) was synthesized for the first time by using a simple hydrothermal coprecipitation method for phosphate removal from wastewater. A maximum adsorption capacity of 194.04 mgP/g was achieved, ranking on the top of known LDHs. Adsorption kinetic experiments showed that 0.02 g/L Ca–La LDH could effectively reduce PO 4 3– P from 1.0 to <0.02 mg/L within 30 min. With the copresence of bicarbonate and sulfate at concentrations 17.1 and 35.7 times of that of PO 4 3– P, the Ca–La LDH showed promising selectivity towards phosphate (with a reduction in the adsorption capacity of <13.6%). In addition, four other (Mg–La, Co–La, Ni–La, and Cu–La) LDHs containing different divalent metal ions were synthesized by using the same coprecipitation method. Results showed much higher P adsorption performance of the Ca–La LDH than those LDHs. Field Emission Electron Microscopy (FE-SEM)-Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), and mesoporous analysis were performed to characterize and compare the adsorption mechanisms of different LDHs. The high adsorption capacity and selectivity of the Ca–La LDH were mainly explained by selective chemical adsorption, ion exchange, and inner sphere complexation.
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DOI
PubMed
高影响因子
Environmental Technology & Innovation
·
2023
·
IF 7.1
Kaifeng Wang,Na Peng,Dongqing Zhang,Haijun Zhou,Jinfeng Gu,Jiahui Huang,Chen Liu,Yang Chen,Yang Liu,Jianteng Sun
This study investigated the adsorption performance of methylene blue using Ca(OH) 2 -modified biochar derived from agricultural and forestry wastes. The results showed that the modified rice straw biochar with 20% Ca(OH) 2 addition paralyzed at 500 °C exhibited the best adsorption performance for methylene blue. The adsorption data were fitted with four kinetic models and four isothermal adsorption models. Among which, the pseudo-second-order kinetic model and Langmuir isothermal model were the best fit, with high correlation coefficient of more than 0.99. The adsorption capacity of Langmuir fitting was 333.3 mg g −1 , which was 12.5 times higher than that for pristine rice straw biochar. The high adsorption capacity was maintained in a wide range of initial pH value of 4–12. SEM-EDX, organic element, surface structure, FTIR and XRD analysis indicated that Ca(OH) 2 modification significantly increased the polarity (higher O/C value), Ca content and the number of oxygen-containing functional groups (C-O and CO 3 2 − ) for pristine rice straw biochar, thereby substantially enhancing and improving the chemical adsorption of methylene blue. The adsorption mechanism involved for methylene blue included functional groups complexation, electrostatic interaction, ion exchange (mainly Ca 2＋ ) and π – π stacking. This study demonstrated that the modified rice straw biochar, as green and environmentally friendly raw material with cost-effectiveness, exhibited a great potential for broad application prospective subject to remediating printing and dyeing-contaminated wastewater.
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DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2022
·Vol. 24
·期 12
·1-13
·
IF 2.533
Wang Yu,Li Yao,Yang Xiao-Hui,Zhang Guo-Hua
Nano-Zirconium diboride (ZrB 2 ) powder was vital raw material for manufacturing ultra-high temperature ceramics (UHTCs) and C/C composite materials, which were widely used in extreme environment. In this paper, a convenient way of synthesizing nano-ZrB 2 powder was proposed. Firstly, the precursor consisting of ultrafine-ZrC and C was obtained via vacuum carbothermal reduction of nano-ZrO 2 . And then, the carbothermal reduction product was boronized by B 4 C in Ca melt. In boronation process, Ca melt would play a key role as decarburizer. By boronation reaction at 1373 K and 1473 K, cauliflower-shaped ZrB 2 particle and smooth polyhedral ZrB 2 particle were obtained, respectively. XRD and BET analyses showed that the grain sizes and BET-equivalent particle diameters of these two products were less than 100 nm.
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高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2022
·
IF 4.966
Xiao Li Li,Peng Liu,Bin Chu,Jin Mei He,Zhen Wang,Song Wang,Chang Sheng Chen,Xiao Hong Ge,Hui Li,Wei Qiang Liu
Myocardial infarction (MI) is a common heart emergency that potentially causes death. Injectable hydrogels with excellent malleability and filling properties are suitable for myocardial injection and can avoid the need for open surgery. In this study, dopamine grafted hyaluronic acid (HADOPA) was synthesized and combined with sodium alginate (Alg) and Ca 2+ -loaded liposomes (Ca-FVI) to prepare a series of injectable thermosensitive sodium hyaluronate/sodium alginate hydrogels (HADOPA/Ca-FVI/Alg). At 37 °C, the HADOPA/Ca-FVI/Alg solution rapidly changed from liquid to hydrogel because of the crosslinking between sodium alginate and the Ca 2+ released from Ca-FVI at a phase transition time of 100–200 s. The HADOPA/Ca-FVI/Alg scaffolds exhibited a porous 3D network structure, controlled porosity, and connected pore properties. Increasing the proportion of HADOPA increases the elasticity and absorbance of hydrogels. Experimental assessment showed that the hydrogels have good biocompatibility and that Alg1-HADOPA is more conducive to the adhesion, proliferation, and spreading of mouse cardiac myocytes while maintaining the best cell state. These findings suggest that HADOPA/Ca-FVI/Alg hydrogels improve cell proliferation and tissue repair, and that they are a promising therapeutic option for cardiac repair after MI.
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高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Lucheng Li,Zehua Zhu,Jie Ni,Xiaojun Zuo
Phosphorus removal has been explored for a long time, however sustainable phosphorus adsorption and recovery with adsorbents recycling is rarely reported. This work proposes a sustainable phosphorus recycling route with calcium-modified powdered activated carbon with chitosan (Ca-PAC-CTS). The morphology, functional groups and crystal structure of Ca-PAC-CTS were characterized. The maximum phosphorus adsorption capacity was 16.73 mg/g Ca-PAC-CTS with Langmuir model at 298 K. Stable phosphorus sorption on Ca-PAC-CTS could be observed at the large range of pH (4– 10) when coexisting with NO 3 − , SO 4 2− , Cl − and F − , except HCO 3 − . 98.95 % The recovery of adsorbed phosphorus could get to 98.95 % using 0.05 M sulfuric acid solution, and the phosphate adsorption efficiency through Ca-PAC-CTS remained to be more than 80 % after five adsorption-desorption cycles, suggesting that Ca-PAC-CTS was one of the promising adsorbents for sustainable removal and recovery of phosphorus in aqueous solution.
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产品关联
DOI
PubMed
高影响因子
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