查找使用阿拉丁产品的科研文献

The polymeric ionic liquids/mesoporous alumina composites: Synthesis, characterization and CO2 capture performance test

Yingying Zhou,Mingfeng Chang,Xiyu Zang,Lan Zheng,Yuqi Wang,Le Wu,Xiaolong Han,Yuqing Chen,Yunsong Yu,Zaoxiao Zhang

The CO 2 capture materials and technology have received much attention in recent years due to the environmental deterioration caused by the greenhouse gas emissions . Several imidazolium polymeric ionic liquids (PILs) were synthesized and immobilized on mesoporous γ-Al 2 O 3 (MA) using ultrasonic immersion method. The prepared adsorbents were characterized by FT-IR, 1 H NMR, EA , TGA , SEM, XRD , BET and TEM, indicating the successful synthesis of the desired PILs/MA. The CO 2 adsorption capacity was investigated under different loading ratios, temperatures, pressures and CO 2 flow rates , whose optimal adsorption conditions were 1/1, 313 K, 5 bar and 10 mL/min, respectively. Moreover, the adsorption curves for P[VCIm]Cl/MA were coincident with pseudo-second order model, and the CO 2 adsorption kinetics model was calculated and obtained. Compared with P[VRIm]Cl and P[VEIm]Cl, P[VCIm]Cl/MA demonstrated an outstanding adsorption amount of 0.562 mmol/g under the suitable conditions, and its regeneration efficiency could achieve 94.8% after 5 times cycle.

CO2 capture and sequestration by sodium humate and Ca(OH)2 from carbide slag

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.

Transformation of CO2 with glycerol to glycerol carbonate by a novel ZnWO4-ZnO catalyst

Jiaxiong Liu,Dehua He

ZnWO 4 -ZnO catalysts with different W content were prepared by conventional hydrothermal and wet impregnation methods and applied in the direct synthesis of glycerol carbonate from CO 2 and glycerol. The crystallite structure, texture property, morphology, redox and acid-base properties and the surface chemical situation of the catalysts were characterized by XRD, BET, TEM, H 2 -TPR, NH 3 /CO 2 -TPD and XPS. The possible activation routes of CO 2 and glycerol were analyzed with DRIFTS and FTIR. ZnWO 4 -ZnO composite catalysts showed better catalytic performances with respect to ZnO in the carbonylation of glycerol with CO 2 . The improved activity of ZnWO 4 -ZnO catalysts was associated with the formation of ZnWO 4 , the interaction between ZnWO 4 and ZnO, and the enhanced moderate acidic property. DIRFTS results showed that chelating bidentate carbonate species was the main adsorption pattern for CO 2 on ZnO, while the introduction of W led to the bridged bidentate carbonate, which became the main adsorption pattern on ZnWO 4 -ZnO. As for the activation of glycerol, zinc glycerolate played an important role in the reaction process. Based on the reaction and characterization results, a plausible reaction route involved a seven-membered ring esters intermediate was suggested for the reaction of CO 2 and glycerol over ZnWO 4 -ZnO catalysts.

Co-Crystal of Paracetamol and Trimethylglycine Prepared by a Supercritical CO2 Anti-Solvent Process

Ziyi Zhao,Guijin Liu,Qing Lin,Yanbin Jiang

Paracetamol (PCA) and trimethylglycine (TMG) were co-crystallized and micronized by means of the supercritical anti-solvent (SAS) process to improve the tabletability of PCA. The effects of operating conditions on particle properties were investigated in detail. Characterizations were performed to confirm the co-crystal state of PCA-TMG. The results indicated that the same crystal form with different crystal habits was prepared. The optimal PCA-TMG co-crystals presented a much larger tensile strength, higher drug content of PCA, and smaller particle size than those obtained using the ball milling (BM) process. The SAS-processed PCA-TMG co-crystals showed an enhanced solubility, dissolution rate, and tableting performance compared to that of BM.

ZIF-8 nanoparticles with tunable size for enhanced CO2 capture of Pebax based MMMs

Wenji Zheng,Rui Ding,Kai Yang,Yan Dai,Xiaoming Yan,Gaohong He

Poly (ether- block -amide) (Pebax) based mixed matrix membranes (MMMs) were prepared by using size-tunable ZIF-8 nanoparticles as fillers. ZIF-8 nanoparticles with sizes of 40, 60, 90 and 110 nm (ZIF-8-40, ZIF-8-60, ZIF-8-90 and ZIF-8-110) were synthesized in microemulsion by controlling the ratio of Zn 2+ to Hmim (1:16, 1:8, 1:5, 1:2). And they were distributed uniformly in Pebax matrix without obvious agglomerations and defects at the loading of 0–20 wt.%, which was confirmed by field-emission scanning electron microscopy (FE-SEM). The incorporation of ZIF-8 resulted in a significant improvement in CO 2 permeability and the CO 2 /N 2 selectivity increased with the BET surface area of ZIF-8 increasing. The enhanced permeability is attributed to an improvement in the free volume of the polymer induced by larger sized ZIF-8, while the increased selectivity results from the high specific surface area of large sized ZIF-8, which can provide more active sites for CO 2 capture and great mass transfer resistance for N 2 . At 5 wt.% loading of ZIF-8-90, the MMM presents the best separation performance with CO 2 permeability of 99.7 Barrer and CO 2 /N 2 selectivity of 59.6, both of which are increased by about 25% by comparison to the pure Pebax membrane. The present study provides an effective way to obtain size-controlled ZIF-8 fillers and high separation performances of Pebax based MMMs.

CO2 responsive wormlike micelles based on sodium oleate, potassium chloride and N,N-dimethylethanolamine

Jinyu Wang,Dongfang Liu,Zhiyu Huang,Cunchuan Zheng

Fabrication of porous graphene electrodes via CO2 activation for the enhancement of capacitive deionization

Yi Zhang,Ling Chen,Shudi Mao,Zhuo Sun,Yenan Song,Ran Zhao

Capacitive deionization (CDI) is a simple, cost-efficient and environmentally-friendly method for brackish water desalination . In order to improve the desalination performance, the inner structures of the porous electrodes should provide more space for ion storage and transportation. Therefore, we utilized an efficient method to synthesize porous graphene electrodes based on the technique of pressurized oxidation and CO 2 activation. The prepared electrodes were characterized electrochemically by cyclic voltammetry , galvanostatic charge/discharge and electrochemical impedance spectroscopy , and the desalination performance between different samples was compared as well. These results showed that AGE-30 had the highest electrosorption capacity (6.26 mg/g) among all samples, and this was attributed to its high specific surface area (898 m 2 /g), high pore volume (1.223 cm 3 /g), high specific capacitance (56.21F/g), and smaller inner resistance. Thus, the CO 2 activation is confirmed to be a useful method for the enhancement of the graphene electrodes for CDI.

Giant Microgels with CO2-Induced On–Off, Selective, and Recyclable Adsorption for Anionic Dyes

Zanru Guo,Qiang Chen,Hongjian Gu,Zhanfeng He,Wenyuan Xu,Jiali Zhang,Yongxin Liu,Leyan Xiong,Longzhen Zheng,Yujun Feng

Adsorbents that are capable of controllable pollutants adsorption and release without secondary pollution are attractive in water treatment. Here, we propose eco-friendly CO2 as a trigger to switch the charge states and collapse–expansion transition of giant microgels consisting of hydrophilic acrylamide and hydrophobic 2-(diethylamino)ethyl methacrylate and demonstrated the on–off, selective, and recyclable adsorption of anionic dyes on microgels under CO2 stimulation. Apart from easy-handling separation from the water by a simple filtration process, the maximum adsorption capacity is as high as 821 mg g–1, and the adsorption isotherms and kinetics obeyed Langmuir isotherm and the pseudo-second-order kinetics models, respectively. The anionic dye can also be separated from the mixture solution using CO2-treated microgels. Moreover, a wastewater treatment prototype with microgel-packed column was fabricated. Under continuous flow condition, the dye was removed and recovered by alternative bubbling CO2 and flushing with aqueous alkali (pH 12). Thus, this type of microgels with CO2-induced protonation–deprotonation transition can serve as a cost-effective, environmentally friendly, and efficient adsorbent for water purification applications.

Controllable Adsorption of CO2 on Smart Adsorbents: An Interplay between Amines and Photoresponsive Molecules

Lei Cheng,Yao Jiang,Shi-Chao Qi,Wei Liu,Shu-Feng Shan,Peng Tan,Xiao-Qin Liu,Lin-Bing Sun

Photoresponsive adsorbents for CO2 capture attract significant attention, because the variation of adsorption capacity can be tailored conveniently by light irradiation. However, all photoresponsive adsorbents reported until now capture CO2 via physical interaction (weak sites). Thus, the selectivity of CO2 over other gases like CH4 is low, and the variation of CO2 adsorption capacity originates from pure structural change via isomerization of photoresponsive units. Despite great challenges, photoresponsive adsorbents for CO2 capture based on chemical interaction (strong sites) are extremely desirable. Here, we report for the first time the construction of photoresponsive adsorbents with chemical adsorption sites for CO2. The control of adsorption capacity is based on the interplay between active amine sites {A, [3-(methylamine)propyl]trimethoxysilane} and photoresponsive azobenzene molecules [P, 4-(3-triethoxysilylpropyl-ureido)azobenzene]. Density functional theory (DFT) calculations reveal that the negative surface potential of amines correlate with the adsorption capacity on CO2. Upon visible light (450 nm) irradiation, trans-isomers of azobenzene are formed and interact with amines, which leads to decreased surface electrostatic potential of amines, and CO2 can thus be adsorbed freely on exposed active sites. In contrast, ultraviolet light (365 nm) irradiation results in the isomerization of azobenzene from trans to cis conformation. The surface electrostatic potential of amines increases obviously, and the active sites are thus blocked. A maximum variation amount is obtained on the adsorbent with comparable density of A and P (0.34 group nm–2), which confirms the interplay between amine sites and photoresponsive molecules. Because amines are specific active sites for CO2, high selectivity of CO2 over CH4 is obtained, and such selectivity is tunable upon irradiation with UV–vis light. We thus demonstrate the successful control of CO2 captured by chemical sites through the interplay between amines and azobenzene molecules, which is impossible or difficult to realize via conventional structural change caused by isomerization of photoresponsive units.

Premodified Sepiolite Functionalized with Triethylenetetramine as an Effective and Inexpensive Adsorbent for CO2 Capture

Meng Yuan,Ge Gao,Xiayi Hu,Xiao Luo,Yangqiang Huang,Bo Jin,Zhiwu Liang

In this work, industrial grade sepiolite (IG-SEP) was premodified with hydrochloric acid, and then premodified sepiolite (SEP) was impregnated with triethylenetetramine (TETA) to create a novel TETA functionalized SEP adsorbent. The effects of TETA loading and adsorption temperature on CO2 adsorption capacity, as well as the CO2 adsorption isotherm and cyclic regenerability were investigated. Results show that, when SEP was optimized at 30 wt % TETA (SEP-TETA-30%), the adsorbent attained a CO2 adsorption capacity as high as 1.93 mmol/g at 50 °C with fast adsorption kinetics and good regenerability. The Freundlich model was best able to fit the experimental adsorption isotherm, and the isosteric heat of adsorption at high CO2 coverage was 28 kJ/mol. The presence of moisture in simulated gas has a positive effect on the adsorption capacity, with less harm to adsorption stability. The adsorbent samples were further characterized by N2 adsorption/desorption, scanning electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The increased surface area and pore volume of the SEP allow for effective immobilization of TETA within its channels. A kinetic study demonstrated that the experimental adsorption data for SEP-TETA-30% were well fitted by the pseudo-second-order model. More importantly, an index of cost efficiency was proposed to evaluate the practicability and competitiveness of amine-impregnated adsorbents. The cost efficiency of SEP-TETA-30% adsorbent was estimated as 0.19 mol CO2/$, which was higher than reported adsorbents, suggesting that the TETA functionalized SEP (SEP-TETA-30%) composite is a promising adsorbent for cyclic postcombustion CO2 capture processes.

The Pros and Cons of Polydopamine-Sensitized Titanium Oxide for the Photoreduction of CO2

Tongyao Wang,Ming Xia,Xueqian Kong

Photocatalytic reduction of CO2into fuels is a promising route to reduce greenhouse gas emission, and it demands high-performance photocatalysts that can use visible light in the solar spectrum. Due to its broadband light adsorption, polydopamine (PDA) is considered as a promising photo-sensitization material for semiconductor photocatalysts. In this work, titanium oxides have been coated with PDA through an in-situ oxidation polymerization method to pursue CO2reduction under visible light. We have shown that the surface coated PDA with a thickness of around 1 nm can enhance the photocatalytic performance of anatase under visible light to reduce CO2into CO. Assisted with additional UV-vis adsorption and photoluminescence characterizations, we confirmed the sensitization effect of PDA on anatase. Furthermore, our study shows that thicker PDA coating might not be favorable, as PDA could decompose under both visible and UV-vis light irradiations.13C solid-state nuclear magnetic resonance showed structural differences between thin and thick PDA coatings and revealed compositional changes of PDA after light irradiation.Keywords:photocatalysis;CO2reduction;anatase;polydopamine;sensitization

Modulation of oxygen vacancy in hydrangea-like ceria via Zr doping for CO2 photoreduction

Lu Li,Pan Li,Yanjie Wang,Lin Lin,Aamir Hassan Shah,Tao He

The defects like oxygen vacancy in a photocatalyst are critical factors to influence the photocatalytic reactivity since they can have an impact on the behavior of photogenerated charge carrier. Since oxygen vacancy can be readily formed in the ceria due to reversible conversion of the oxidation states between Ce 4+ and Ce 3+ , here ceria is used as the target material. A versatile and facile co-precipitation method was adopted to synthesize hydrangea-like Ce 1−x Zr x O 2 (x = 0.00, 0.025, 0.05 and 0.10). The amount of oxygen vacancy in the obtained catalysts can be modulated by altering the molar fraction of doped Zr. The composition, morphology, physico-chemical properties of the as-synthesized Ce 1−x Zr x O 2 were characterized by using different techniques. It is found that Zr doping into the ceria crystal lattice can lead not only to an enhanced specific surface area and surface adsorption capacity for CO 2 , but also to an increased concentration of oxygen vacancy that can exist in the bulk and on the surface. The Zr-doped ceria exhibits an enhanced activity for photoreduction of CO 2 , which can be explained based on the influence mechanism of oxygen vacancy. This work shows that the oxygen vacancy in the ceria can be modulated via a feasible Zr doping approach, which may help design the photocatalysts with high activity for CO 2 photoreduction.