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
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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
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材料科学
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高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Panpan Wang,Meiyu Shi,Bochen Zhao,Yuan Shu,Qiang Niu,Pengfei Zhang
Carbide residue, a highly alkaline industrial solid waste generated during acetylene production, is primarily composing of Ca(OH) 2 . In this study, a top-down solid-state redispersion strategy. By synergizing mechanochemical activation with surfactant capping, we achieving the recycling of carbide residue to synthesize Ca(OH) 2 -CTAB anosheet-based desulfurization agent. The resultant material exhibits a significantly enhancing BET specific surface area (30.2 m 2 ·g −1 ) and abundant pore architecture. Comparative evaluations with Ca(OH) 2 -P123 and raw carbide residue revealing the superior performance of the Ca(OH) 2 -CTAB adsorbent, demonstrating a sulfur dioxide adsorption capacity of 2.57 mmol·g −1 is a 2-fold improvement over untreating carbide residue. Furthermore, significantly extends the fixed-bed penetration time to 43869 seconds. Comprehensive characterization through TG, FTIR, BET, SEM, TEM, and AFM elucidating the relationship between the nanosheet morphology and its exceptional desulfurization performance. This work provides a green methodology for upcycling industrial alkaline waste into functional nanomaterials for environmental remediation.
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高影响因子
MATERIALS AND STRUCTURES
·
2023
·Vol. 56
·期 1
·1-15
·
IF 3.8
Song Yufeng,Zhang Yi,Shen Siyi,Pan Chenyu,Yan Dongming,Wang Zhiguang,Wang Su,Ruan Shaoqin
This study aims to explore the effects of different Ca(OH) 2 contents on the mechanical performance and corrosion behaviors of steel in Calcium sulfoaluminate (CSA) cement, where compressive strength, corrosion potentials of reinforcements, corrosion current density, pH of pore solution as well as mortar resistivity of CSA/Ca(OH) 2 mortar were researched, and the corrosion behaviors were further interpreted by the clarification of hydration phases through microstructural analyses. The initial results highlighted the positive effects of using adequate Ca(OH) 2 (~ 6%) in CSA mortar in terms of strength, yet its excessive addition could delay the subsequent hydration reaction of CSA. Meanwhile, with an increased quantity of Ca(OH) 2 , the amount of some hydration phases, such as Al(OH) 3 reduced, resulting from their reaction with Ca(OH) 2 . Finally, the corrosion current density increased with the reduced mortar resistivity when the reinforcement in CSA/Ca(OH) 2 system was corroded, and their relationship was also provided in this study.
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高影响因子
Materials
·
2023
·Vol. 16
·期 4
·1568
·
IF 3.4
Feng Wang,Yaoqi Gu,Jianrui Zha,Shuya Wei
Ca(OH)2nanoparticles are effective materials for cultural heritage restoration, hazardous substance absorption and photocatalyst. However, many methods are complex, and the particle sizes are usually above 80–100 nm, involving mediocre efficacy for application in the stone restoration field. In this work, Nano Ca(OH)2with diameters less than 70 nm and composited with Graphene Quantum Dots (GQDs) were successfully synthesized in aqueous media. The morphology and structure of the nanoparticles were investigated with TEM, HRTEM, XRD, Raman and FTIR. The particle size distribution and relative kinetic stability of the Ca(OH)2in ethanol were performed using a laser particle size analyzer and spectrophotometer. Firstprinciple calculations based on the spin-polarized density functional theory (DFT) were carried out to study the reaction process and combination model. The nanoparticles, as prepared, are composed of primary hexagonal crystals and high ammoniated precursors, which have a positive effect on reducing the grain size, and interacted with the GQDs hybrid process. According to the First-principle calculations results, the energy variation of the whole reaction process and the bonding mode between Ca(OH)2and GQDs can be understood better.Keywords:Ca(OH)2;Graphene Quantum Dots;DFT;complex;nanoparticles
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PubMed
高影响因子
RSC Advances
·
2021
·Vol. 11
·期 53
·33626-33636
·
IF 3.361
Leliang Wu,Yiting Lin,Yimin Zhang,Peng Wang,Mingjun Ding,Minghua Nie,Caixia Yan,Shiyao Chen
Alkaline substances could activate peroxymonosulfate (PMS) for the removal of organic pollutants, but relatively high alkali consumption is generally required, which can cause too high pH of the solution after the reaction and lead to secondary pollution. Within this study, PMS activated by a relatively low dosage of Ca(OH)2 (1 mM) exhibited excellent efficiency in the removal of bisphenol S (BPS). The pH of the solution declined to almost neutral (pH = 8.2) during the reaction period and conformed to the direct emission standards (pH = 6–9). In a typical case, BPS was completely degraded within 240 min and followed the kinetics of pseudo-first-order. The degradation efficiency of BPS depended on the operating parameters, such as the Ca(OH)2, PMS and BPS dosages, initial solution pH, reaction temperature, co-existing anions, humic acid (HA), and water matrices. Quenching experiments were performed to verify that singlet oxygen (1O2) and superoxide radicals (O2˙−) were the predominant ROS. Degradation of BPS has been significantly accelerated as the temperature increased. Furthermore, degradation of BPS could be maintained at a high level across a broad range of pH values (5.3–11.15). The SO4−, NO3− did not significantly impact the degradation of BPS, however, both HCO3− and HA inhibited oxidation of BPS by the Ca(OH)2/PMS system, and Cl− had a dual-edged sword effect on BPS degradation. In addition, based on the 4 identified intermediates, 3 pathways of BPS degradation were proposed. The degradation of BPS was lower in domestic wastewater compared to other naturals waters and ultrapure; nevertheless, up to 75.86%, 77.94% and 81.48% of BPS was degraded in domestic wastewater, Yaohu Lake water and Poyang Lake water, respectively. Finally, phenolic chemicals and antibiotics, including bisphenol A, norfloxacin, lomefloxacin hydrochloride, and sulfadiazine could also be efficiently removed via the Ca(OH)2/PMS system.
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PubMed
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2018
·Vol. 44
·期 5
·3613-3627
·
IF 1.674
Sun Zhiguo,Feng Run,Zhang Li,Xie Hongyong
A new method of carbon capture and sequestration (CCS) by sodium humate (HA–Na) and Ca(OH) 2 from carbide slag (CS) solution was proposed. The effects of various operating parameters, such as the additive amount of HA–Na, pH, temperature, gas flow rate, CO 2 inlet concentration, and stirring rate on both the Ca ion concentration and Ca conversion rate were investigated in a lab-scale bubbling reactor. The synergistic mechanism of HA–Na and Ca(OH) 2 from CS on CCS is also put forward and demonstrated. The experimental results indicate that HA–Na may improve significantly the CCS capability of CS since the Ca conversion rate of CS is increased 10% by HA–Na additive. The pH is a key factor for the CO 2 absorption process and HA–Na may lower the rate of pH decrease of Ca(OH) 2 solution. The increasing temperature, stirring rate, and CO 2 inlet concentration are favorable to CO 2 capture, as well as low gas flow rate. Ca(OH) 2 from CS mixed with HA–Na solution shows good performance in CO 2 uptake, and the Ca conversion rate reaches 99% with 100 mL of Ca(OH) 2 (1.5 g/L) solution mixed with 0.1 g HA–Na at 40 °C, a gas flow rate of 0.1 L/min, and an inlet CO 2 concentration of 100% at ambient pressure. Moreover, calcite CaCO 3 is is identified as the main product of CO 2 capture by X-ray diffraction and scanning electron microscopy analysis.
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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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高影响因子
AICHE JOURNAL
·
2015
·Vol. 62
·期 2
·580-588
·
IF 2.748
Zhixing Zhao,Xiao-Qiao Wang,Luting Ling,Cai-Feng Wang,Su Chen
The bottleneck of large-scale production of semiconductor quantum dots (QDs) is how to solve heavy metal ions waste water and the rapid separation during industrial process. A facile strategy for fabricating CdTe@Ca(OH) 2 nanocrystals exhibiting both improved photoluminescence (PL) stability and prolonged PL lifetime via an economical coprecipitating technology is reported herein. The procedure on capping CdTe QDs into Ca(OH) 2 crystals can enable the products to be easily filtrating separation and the content of residual Cd 2+ filtrate solution to be reached to 0.238 ppm level. Also, fluorescent rod-like heterocrystals by addition of saturated CaCl 2 solution is constructed. CdTe@Ca(OH) 2 nanocrystals is utilized further as phosphor powders to construct white light emitting diode (WLED). The WLED presented, here, has good photoelectric properties with color rendering index of 82.4 at 350 mA, a color temperature of 4643 k, and Commission Internationale de L'Eclairage coordinate of (0.3548, 0.3532), belonging to the white gamut, showing great potential in industrial application. © 2015 American Institute of Chemical Engineers AIChE J , 62: 580–588, 2016
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高影响因子
ENERGY
·
2017
·
IF 4.52
J. Yan,C.Y. Zhao,Z.H. Pan
Cyclic stability is a key factor in the design of thermochemical heat storage systems . Because carbon dioxide (CO 2 ) may react with heat storage materials and lead to a decrease in energy storage efficiency, the effect of CO 2 on Ca(OH) 2 /CaO and Mg(OH) 2 /MgO systems is investigated in this study. The experimental results show that CO 2 reacts with CaO in the water vapor that appears during the heat release process. Therefore, in the design of Ca(OH) 2 /CaO systems, CO 2 should be cleared from the system. The results from Mg(OH) 2 /MgO systems show that CO 2 only slightly reacts with MgO and Mg(OH) 2 during heat storage and release processes. This study indicates that carbonic acid (H 2 CO 3 ) could easily react with CaO/Ca(OH) 2 to form CaCO 3 during heat release processes. Generally, the remaining CO 2 reduces the reversibility of Ca(OH) 2 /CaO systems but has only a slight influence on Mg(OH) 2 /MgO systems. In addition, the experimental results show that carbonate shell does not exist in rehydration for both of the CaO/MgO samples, but the influence of CO 2 on the entire process increases after each cycle.
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高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2026
·
IF 5.1
Yong Zheng,Haobin Wu,Shouchao Zhong,Xun Kan,Ye Song,Fujian Liu,Wei Lin,Jianchun Wang,Lilong Jiang
The development of efficient and reusable sorbents for SO 2 removal from flue gas has attracted considerable attention. Herein, we report a “chainmail” structured Ca-based SO 2 sorbent by encapsulating Ca species within ordered mesoporous carbon (OMC), denoted as Ca(OH) 2 @OMC- x , where x denotes the Ca(OH) 2 mass fraction (wt%). The OMC was prepared via a one-step solvent-free mechanochemical assembly: the precursors and a block copolymer template (Pluronic F127) were ground to form a preorganized composite, followed by solidothermal treatment and calcination to remove the template and carbonize the polymer. The obtained OMC was then impregnated with a Ca precursor and calcined to strengthen interfacial interactions, encapsulating the Ca species within the OMC framework. Finally, steam treatment converted the confined Ca species into finely dispersed Ca(OH) 2 active domains. The resulting Ca(OH) 2 @OMC- x exhibits a large BET surface area (169.4–290.3 m 2 /g), long-range ordered mesoporosity with a narrow pore size distribution (∼5.5 nm), and well-dispersed Ca active phases with enhanced stability. Consequently, Ca(OH) 2 @OMC- x serves as an efficient and reusable solid sorbent for SO 2 capture, exhibiting a high SO 2 adsorption capacity of 11.24 mmol/g and maintaining 98.6% of its initial capacity after five adsorption–desorption cycles. This study provides an effective “chainmail encapsulation” materials design strategy for scalable SO 2 abatement under complex flue gas conditions.
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高影响因子
ENERGY
·
2025
·
IF 9.4
Qi Zhou,Liu Wu,Jingyue Wang,Jie Liang
Lignin, with its complex structure and high stability, poses a significant challenge in the directed depolymerization to obtain aromatic-rich bio-oil. To prevent the formation of hard-shelled char resulting from the melting and agglomeration of lignin during pyrolysis, this study proposed a dual strategy combining Ca(OH) 2 pretreatment and Beta zeolite, which demonstrated a synergistic effect through β-O-4 bond cleavage, effectively suppressing lignin condensation while achieving high aromatic selectivity. In this study, the influence of various operational parameters was examined. Key variables including pretreatment procedures, concentration levels, catalyst selection, catalyst-to-raw material ratio, carrier gas velocity, and pyrolysis thermal conditions were analyzed to determine their effects on the critical processes. Pretreatment with 5 wt% Ca(OH) 2 significantly reduced lignin agglomeration during pyrolysis. Using Beta zeolite (1:1 mass ratio) in CFP at 500 °C with 75 mL/min carrier gas flow increased bio-oil yield from 5.0 wt% to 7.5 wt% and enhanced aromatic selectivity from 1.9 area% to 84.9 area%. Using 2-phenoxy-1-phenylethanol (α-OH-PPE) as a model compound, we found Ca(OH) 2 pretreatment and Beta zeolite together enhanced β-O-4 bond cleavage in lignin. This synergistic approach facilitated efficient bond cleavage and showed remarkable effectiveness in aromatic production.
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高影响因子
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