CEMENT AND CONCRETE RESEARCH
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2026
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IF 14
Zedong Zhou,Hangxi Liu,Juanlong Li,Yiru Yan,George Dan Miron,Barbara Lothenbach,Biwan Xu,Ming Fang,Xiaoli Tan,Bin Ma
Calcium silicate hydrate (C-S-H), the principal binding phase in Portland cement, plays a critical role in the immobilization of heavy metals, yet a quantitative and mechanistic understanding of Cu 2+ uptake by C-S-H remains incomplete. This study investigates the immobilization behavior of Cu 2+ by C-S-H with systematically controlled Ca/Si ratios (0.6–1.6) and develops a thermodynamically consistent sublattice solid-solution model. The C-S-Hs were synthesized under sorption equilibrium conditions and characterized to determine their structural evolution with Ca/Si ratio. Cu 2+ sorption was subsequently examined on pre-synthesized C-S-Hs, combined with spectroscopic analyses to elucidate Cu coordination environments. The results show that Cu 2+ is immobilized predominantly through structural incorporation at low Cu 2+ loadings rather than hydroxide precipitation. With increasing Cu 2+ concentration, Cu 2+ progressively intercalates into the interlayers of C-S-H, partially replacing interlayer Ca 2+ and forming Si-O-Cu linkages associated with Q 2 silicate sites. The Ca/Si ratio strongly controls both uptake capacity and binding mechanism. High Ca/Si ratios promote silicate-chain polymerization through conversion of Q 1 to Q 2 units, whereas extremely low Ca/Si ratios induce redistribution between Q 2 and Q b 2 species. At intermediate Ca/Si ratios, Cu 2+ is mainly stabilized as hydroxyl-associated species. Once the sorption capacity is exceeded, excess Cu 2+ transforms into CuO under alkaline conditions. Based on these observations, a CASH+Cu thermodynamic model incorporating five Cu-bearing endmembers was developed and calibrated using both aqueous and solid-phase data. The model quantitatively reproduces Cu uptake, solution chemistry, and phase assemblages, providing a predictive framework for Cu 2+ retention in cementitious systems.
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FOOD RESEARCH INTERNATIONAL
·
2025
·
IF 8
Yongxin Li,Wenni Tian,Fang Tian,Yanrong Zhao,Xuguang Zhang,Jie Xiao
This study introduces an innovative double emulsion (DE) system for the co-delivery of water-soluble 5-methyltetrahydrofolate calcium (5-MTHF-Ca) and lipid-soluble vitamin D 3 (VD 3 ), addressing the challenge of synchronized delivery for nutrients with divergent solubility. Through a two-step emulsification strategy, co-loaded DEs (C-5-MTHF-Ca & VD 3 ) exhibited superior colloidal stability compared to single-loaded counterparts (S-5-MTHF-Ca and S-VD 3 ), retaining 88.17 ± 2.64 % of 5-MTHF-Ca and 81.99 ± 2.45 % of VD 3 after 15-day storage. During in vitro digestion, co-loaded DEs demonstrated delayed lipid hydrolysis (38.01 ± 5.55 % FFA release at 30 min vs. 43.88 ± 13.79 % for S-VD 3 ) and preserved structural integrity through gastric phases, while synchronized intestinal micellar incorporation increased VD 3 bioaccessibility by 19.82 %. Ex vivo fluorescence tracking in mice revealed spatiotemporal co-localization of both actives, with jejunal accumulation peaking at 2–4 h post-administration, aligning with Ussing chamber results showing 2.13-fold enhanced VD 3 permeation and 1.80-fold enhanced 5-MTHF-Ca transport in co-loaded systems. Pharmacokinetic studies in rats confirmed bioavailability enhancement, with co-loaded DEs achieving 1.37-fold higher VD 3 AUC (6707.08 ± 1123.82 vs. 4898.36 ± 685.16 ng·h/mL) and 1.19-fold increased 5-MTHF-Ca C max compared to single-loaded formulations. The extended T max (by twofold) and prolonged t 1/2 K a (1.81-fold for 5-MTHF-Ca) indicated optimized intestinal retention, attributed to the phase-separated W/O/W architecture protecting actives from premature degradation. These findings establish a platform for nutrient co-delivery, where rational DE design enables spatiotemporally coordinated gastrointestinal transit, and synergistic absorption.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2016
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IF 3.014
Di Pan,Yiping Guo,Kai Zhang,Huanan Duan,Yujie Chen,Hua Li,Hezhou Liu
In this work, (K 0.48 Na 0.52 )NbO 3 −0.05Ca x (Bi 0.5 Na 0.5 ) 1− x ZrO 3 lead-free piezoelectric ceramics were prepared by a conventional solid-state sintering method. The effects of Ca content on their phase structure, microstructures, and piezoelectric properties were systematically studied. With the increasing of Ca content, the rhombohedral-orthorhombic phase temperature gradually increases and Curie temperature of the ceramics without a conspicuous change. In addition, appropriate Ca ( x ≤ 0.2) content promotes the grain growth, which leads to a denser microstructure. Rhombohedral-orthorhombic and orthorhombic-tetragonal phase coexistence has been obtained in the composition range of 0.15 ≤ x ≤ 0.3. The ceramics with x = 0.2 possess enhanced piezoelectric properties of d 33 ∼308 pC/N and k p ∼49.0%, together with a high Curie temperature of T C ∼328 °C. Therefore, the material system of this work is a promising candidate for piezoelectric applications.
研究领域:
材料科学
·
物理学
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MATERIALS & DESIGN
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2020
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IF 6.289
Xuefeng Zhou,Xi Cheng,Danlei Xing,Qi Ge,Yan Li,Xianghong Luan,Ning Gu,Yunzhu Qian
Bioactive synthetic scaffolds with 3D porous structure are the most attractive materials among various guided bone regeneration membranes. However, its osteogenic potential is still insufficient. This study was aimed to develop a Calcium surface-anchored Collagen I-PLGA/PCL scaffolds (PP/COL I-pDA-Ca) with enhanced osteogenicity. PP/COL I-pDA-Ca was electrospun from a collagen I-blended PLGA/PCL matrix and then modified by the chelation of Ca-ions via mussel-inspired polydopamine coating. PLGA/PCL, PLGA/PCL-polydopamine, PLGA/PCL-pDA chelated by Ca-ions were used as controls. Osteogenic effects of the scaffolds were examined using MC3T3-E1 cell culture. PP/COL I-pDA-Ca maintained 3D porous architecture with interconnected pores formed by randomly-oriented filamentous fibers and MC3T3-E1 cells cultured on it for 12 h or 24 h were more stretched and spread than those on the controls. PP/COL I-pDA-Ca significantly upregulated α10, α11 and β1 integrin expression after 48 h culture. ALP activity, OCN, OSX, BMP2 and RUNX2 expression of MC3T3-E1 cells cultured on PP/COL I-pDA-Ca scaffolds for 7 and 14 days were substantially enhanced when compared to controls ( p < 0.05). The pDA-based Ca chelation, COL I incorporation and 3D bionic structure promoted cell adhesion and osteogenic differentiation of MC3T3-E1 cells. This novel PP/COL I-pDA-Ca scaffolds is an attractive alternative for guided bone regeneration.
研究领域:
生物材料
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组织工程
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生物医学工程
·
骨科
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ACTA MATERIALIA
·
2022
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IF 9.209
Qian Liu,Ke-Feng Liu,Qi-Qi Wang,Xiao-Cun Liu,Fang Yu,Jian Liu,Yuan-Yuan Su,Sheng-Qing Xia
In this report, for the first time TiNiSi-type Zintl phases with the nominal formulae of ALiSb (A = Ca, Sr, Eu, Yb) were systematically investigated on their thermoelectric properties. The results indicated that ALiSb Zintl phases possessed intrinsically low lattice thermal conductivity despite the simple structure. In combination of thorough crystallographic and theoretical investigation, rattling-like scattering behavior originating from the Li atoms was suggested. As a result, the pristine ALiSb materials featured decent zT values of 0.4–0.7 at 823 K. With the electrical and thermal transport properties further optimized by configuring the solid solutions such as Sr 0.8 Eu 0.2 LiSb, the material approached a maximum zT up to 1.2 at the same temperature. These breakthroughs are distinct from the previous knowledge that low thermal conductivity in Zintl phases is usually realized through complex crystal structures, and for compounds with simple structures such as the TiNiSi type it is common to have poor thermoelectric performance. Owing to such a rattling-like scattering behavior, now light-element containing Zintl phases can be a promising resource for thermoelectric considerations as well. The mechanism is surely interesting and worth of in-depth investigation.
研究领域:
材料科学
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热电材料
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固体化学
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晶体学
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能源材料
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Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Ayesha Idrees,Ali Shan,Waqas Qamar Zaman,Ali Mohsin,Zain Abbas,Tanvir Shahzad,Atif Shakeel,Shuguang Lyu
M-metal (Ca and Cu) doped Ca-Fe 2 O 3 and Cu-Fe 2 O 3 catalysts were synthesized using solvothermal method. The Ca-Fe 2 O 3 and Cu-Fe 2 O 3 catalysts were characterized by XRD, Raman spectroscopy , SEM , TEM and XPS spectroscopy. The catalytic performance of 6%Ca-Fe 2 O 3 and 5%Cu-Fe 2 O 3 catalysts for trichloroethylene (TCE) removal were improved by M-metal doping leading to TCE removal at 99.8% in 1 h, which were three folds greater than by simple a- Fe 2 O 3 in the presence of persulfate (PS). Ca and Cu doping formed defective structure and created more oxygen vacancies thereby generating abundant active species during PS activation process. Further, the influence of catalysts’ dosage, oxidant dosage, solution pH, inorganic anions, and dissolved oxygen were evaluated. Complete removal of TCE was also obtained at weak alkaline pH condition. The greater specific surface area and the improved electrical conductivity was attributed to the huge generation of O 2 •– and 1 O 2 species which played major part in TCE removal. Scavenging tests and ESR spectroscopy confirmed the dominant role of O 2 •– and 1 O 2 in TCE degradation. The stability and viability of 6%Ca-Fe 2 O 3 and 5%Cu-Fe 2 O 3 catalysts were evaluated by repetition tests and in the presence of surfactants, TCE removal in real water matrix, and in the degradation of multi-pollutants.
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Advanced Energy Materials
·
2022
·Vol. 12
·期 22
·2200392
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IF 29.698
Peng Zhong,Kazuaki Toyoura,Lulu Jiang,Lubing Chen,Sara Adeeba Ismail,Naoyuki Hatada,Truls Norby,Donglin Han
A significant hydration and protonic conduction in La 2 NiO 4+ δ -based Ruddlesden–Popper (RP) oxides will enable their use as positrode materials in proton ceramic electrochemical cells (PCECs). Unlike perovskite electrolytes and positrode materials, where protons reside and jump on regular oxide ions, RP oxides such as La 2 NiO 4+ δ may contain oxygen interstitials and offer the possibility that protons locate on and migrate by help of these, suggesting a mechanism by which positrodes may operate by triple conduction. Here, theoretical calculations that support proton migration between interstitial oxide ions in the rock-salt layer via unshared oxide ions in the perovskite layer are reported. Furthermore, water contents of pristine La 2 NiO 4+ δ and La 2- x A x NiO 4+ δ ( A = Ca, Sr, Ba) are reported, showing that hydration increases with the level and basicity of the dopant. Hebb-Wagner blocking electrode measurements show significant partial protonic conductivity in all samples. The effects of doping on hydration and of p H 2 O on the p-type conductivity suggest that protons reside primarily on structural oxide ion, but a role of interstitial oxide ions for dissolution and migration of protons cannot be ruled out in cases with oxygen excess. The results are instructive for further studies and optimization of RP oxides as potential positrode materials for PCECs.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 29
·期 4
·6375-6388
·
IF 4.223
Ahmad Khalil,Shah Izaz Ali,Ali Sharafat,Khan Muhammad Tariq,Qureshi Muhammad Bilal Ahmed,Shah Syed Hassan Ali,Ali Asmat,Rashid Wajid,Gul Hifza Nayab
Ferric hydrate has been extensively applied for the removal of various types of pollutants from wastewater because of its low cost and high efficiency. However, its wide-scale application has been greatly restricted by high-dose and low-adsorption capacity. Therefore, a novel Ca-doped ferrihydrite adsorbent has been synthesized and used for the enhanced removal of fluoride from wastewater in the presence of other co-existing ions. At 5 mg/L initial fluoride concentration and pH 5, the removal efficiency of fluoride approached to 97.5% and remained stable. Similarly, with the increase of dose from 100 to 300 mg/L, the fluoride removal linearly increased to 98% and remained plateau at neutral pH. Also, the presence of co-existing ions such as NO 3 − , SO 4 2− , Cl − , and natural organic matter has not significantly influenced the removal performance of the adsorbent. Fluoride removal best fit the pseudo-second-order reaction kinetics and Langmuir isotherm model. The prepared adsorbent exhibited a maximum adsorption capacity of 53.21 mg/g for fluoride uptake from water. The SEM-EDX confirmed the doping of Ca onto the ferrihydrite where the elemental peaks of Ca and Fe emerged at the energy value of about 3.6 Kev and 7.1 Kev respectively in EDX analysis. In addition, SEM results of Ca-doped ferrihydrite adsorbent illustrated that a large microplates type of products was acquired after synthesis. The regeneration results confirmed that adsorbent could retain their original adsorption capacity after five regeneration cycles. The current study suggested that Ca-doped ferrihydrite has the application potential for the enhanced adsorption of fluoride from the water phase. Graphical abstract
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Journal of Environmental Chemical Engineering
·
2021
·
IF 5.909
Shuo Yan,Yun Li,Jilin Cao
The calcium nitrate (Ca(NO 3 ) 2 ) waste generated from the production of nitrophosphate fertilizers brings about serious environment and human health issues. Using Ca(NO 3 ) 2 waste and ammonium bicarbonate (NH 4 HCO 3 ) fertilizer as raw materials, higher-value spherical calcite mesocrystals have been synthesized via precipitation method. The synthesis conditions are optimized from the aspects of dispersant, crystal control agent and reaction temperature, and the mechanism that regulates the size and morphology of calcite is illustrated. The synthesized spherical calcite mesocrystals exhibit the small particle size of ca. 5 µm and high specific surface area of 84.44 m 2 /g. Under the dispersion effect of polyvinylpyrrolidone, the adsorption of crystal control agent citric acid on the calcite particles results in the formation of the spherical mesocrystal morphology. The yield of calcite in this process could reach 94.3%. Ca 2+ ion remaining in the mother liquor are further removed in the form of CaCO 3 by addition of calcium oxide , and a mixture of ammonium nitrate and a small amount of NH 4 HCO 3 is obtained by concentrating the filtrate, which can be used as nitrogen fertilizers. This work provides a new insight into the low-cost synthesis of spherical calcite mesocrystals with the high specific surface area and the comprehensive utilization of Ca(NO 3 ) 2 waste.
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2021
·Vol. 328
·期 3
·1019-1032
·
IF 1.371
Wang Yugang,Zhang Weimin,Chen Jiahong,Guo Yadan
A new type of Ca/Fe-phosphate composite CFP(CN) was prepared by a sol–gel method. The effects of pH, reaction time, initial uranium concentration, reaction temperature, and Mn(II) selective adsorption were investigated by static batch experiments. The adsorption process of CFP(CN) on U(VI) was in line with the quasi-second-order kinetic model and the Langmuir adsorption isotherm model. The results of thermodynamic analysis show that the adsorption of U(VI) by CFP(CN) is a spontaneous process with heat absorption and entropy increase. The adsorption mechanism of U(VI) on CFP(CN) was investigated by SEM, XRD and FT-IR.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Yongjun Sun,Shengbao Zhou,Wenquan Sun,Sichen Zhu,Huaili Zheng
In order to effectively remove the dissolved heavy metals and the heavy metals on the colloidal particles during the flocculation process, a novel dual-functional chitosan flocculant CMCTS-g-P(AM-CA) is prepared by ultraviolet light-initiated graft polymerization using CMCTS, AM, and ammonium dithiocarbamate. The main influencing factors of monomer concentration, monomer ratio, pH value, photoinitiator concentration, and illumination time are investigated on the basis of intrinsic viscosity, grafting rate, and grafting efficiency of CMCTS-g-P(AM-CA). Characterization results provided empirical evidence for existence of chelating groups. In addition, CMCTS-g-P(AM-CA) was applied to treat the simulated heavy metals and electroplating wastewater. The effect of CMCTS-g-P(AM-CA) dosage, pH value, and reaction G value on flocculation efficiency was also explored. After the two-stage flocculation, the residual concentration of Ni(II), COD, and turbidity of actual electroplating wastewater decreased to 0.96 mg/L, 93.00 mg/L, and 1.71 NTU after flocculation tests at optimal condition, respectively. Finally, the “3E” triangular evaluation model is established and applied to evaluate the flocculation performance of CMCTS-g-P(AM-CA) on the actual heavy metal wastewater further, thereby proving its excellent chelation flocculation performance.
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Arabian Journal of Chemistry
·
2023
·
IF 6
Fulong Cheng,Yinian Wang,Yuting Fan,Dan Huang,Jie Pan,Wei Li
Biochar-based adsorbents for phosphate removal from wastewater has gained increasing attention and achieved significant progress. However, there is still much room for the enhancement on adsorption performance in terms of removal rate, adsorption capacity and pH application range. Herein, novel Ca-Al-La modified biochar adsorbents in this study were synthesized for enhancing phosphate adsorption in wastewater. The synthesis parameters of adsorbents were optimized by using the response surface methodology (RSM). The Ca-Al-La modified biochar adsorbent synthesized under the optimal conditions (CAL-MBC) exhibited superior adsorption capability towards phosphate. Specifically, CAL-MBC achieved a rapid removal rate to reach the adsorption equilibrium within 1 h, a maximum phosphate adsorption capacity of 152.9 mg/g, and excellent pH stability within a broad pH range of 3.0–11.0. The adsorption mechanisms involving electrostatic interaction, precipitation and inner-sphere complexation via ligand exchange were responsible for the excellent adsorption performance of phosphate on CAL-MBC. This study verifies CAL-MBC as a promising metal modified biochar adsorbent to enhance phosphate removal from wastewater.
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