水稻秸秆蒸汽爆破-酯化改性制备吸油材料

以水稻秸秆为原料进行蒸汽爆破-酯化改性制备溢油吸附材料。未改性水稻秸秆有一定的吸油能力,其饱和吸油倍率、吸水倍率分别为5.66 g·g^-1,7.59 g·g^-1。通过对水稻秸秆进行蒸汽爆破-酯化改性后,发现其亲油疏水性能得到显著改善。对酯化反应的影响因素进行系统考察,得到优化的改性条件为反应温度为80℃,催化剂对甲基苯磺酸酐浓度为0.75%,反应时间为6 h。改性后水稻秸秆吸油倍率为8.54 g·g^-1,吸水倍率为0.10 g·g^-1。对蒸汽爆破-酯化改性前后水稻秸秆材料进行BET、XRD以及FT-IR表征,发现爆破处理后材料的孔径增大;非结晶态以及乙酰基特征峰的出现说明水稻秸秆发生酯化改性反应。     

污泥含炭吸附剂的制备及其吸附模拟烟气中汞蒸汽的应用(英文)

The carbonaceous adsorbent was prepared from mixtures of dewatered sludge and sawdust with enhanced ZnCl2 chemical activation.Characteristics of the adsorbent were studied using scanning electron microscope(SEM) ,Fourier transform infrared spectroscopy(FT-IR) ,and adsorption of nitrogen.The surface analysis showed that the carbonaceous adsorbent had good specific surface and porosity(394 m 2 ·g-1of BET surface,0.12 and 0.10 ml·g-1of microporous and mesoporous volume,respectively) .The oxygen functional groups such as OH,C O and C O were found on the surface by FTIR and XPS(X-ray photoelectron spectroscopy) .The adsorption of elemental mercury(Hg0) on the carbonaceous adsorbent was studied in a fixed bed reactor.The dynamic adsorption capacity of carbonaceous adsorbent increased with influent mercury concentration,from 23.6μg·g-1at 12.58μg·m-3to 87.9μg·g-1at 72.50μg·m-3,and decreased as the adsorption temperature increased,from 246 μg·g-1 at 25°C to 61.3μg·g-1 at 140°C,when dry nitrogen was used as the carrier gas.The carbonaceous adsorbent presented higher dynamic adsorption capacity than activated carbon,which was 81.2μg·g-1and 53.8μg·g-1respectively.The adsorption data were fitted to the Langmuir adsorption model.The physical and chemical adsorption were identified on the adsorbent.     

Catalytic adsorptive desulfurization of mercaptan,sulfide and disulfide using bifunctional Ti-based adsorbent for ultra-clean oil

Ultra-deep desulfurization of transformer oil is of great demand among power industry. In this work, the effective and deep removal of various types of organosulfurs, including mercaptan, sulfide and disulfide via catalytic adsorptive desulfurization (CADS) using bifunctional Ti-based adsorbent is reported. Compared to adsorptive desulfurization (ADS), dramatically improvement of the organosulfur uptakes were achieved under CADS process. The equilibrium adsorption capacity at 5 μg·g^-1 S reached up to 15.7, 33.4, 11.6 and 11.9 mg·g^-1 for propyl mercaptan(n-PM), dimethyl sulfide(DMS), di-t-butyl disulfide (DTBDS) and dibenzyl disulfide (DBDS), which was 262, 477, 97 and 128 times to that of ADS process, respectively, and was the highest among the reported desulfurization adsorbents. Moreover, it achieved superior breakthrough capacity of 2050, 530 and 210 ml F·(g A)^-1 at the breakthrough S concentration of 1 μg·g^-1 of the commercial transformer oil S containing 10, 50 and 150 μg·g^-1, respectively. The effectiveness of CADS is associated to the transformation of sulfur species to higher polar sulfonic species with the assistance of mild oxidant, which can be readily captured by silanol groups on SiO₂ through H-bonding interaction. The excellent recyclability of the adsorbent can be realized through solvent washing or oxidative air treatment. This work provides an effective and economic approach for the elimination of trace amount of mercaptan, sulfide and disulfide from transformer oil.     

Adsorption of congo red on mesoporous activated carbon prepared by CO2 physical activation

This research demonstrates the production of mesoporous activated carbon from sargassum fusiforme via physical activation with carbon dioxide. Central composite design was applied to conduct the experiments at different levels by altering three operating parameters. Activation temperature(766–934 ℃), CO_2 flow rate(0.8–2.8 L·min(~-1)) and activation time(5–55 min) were the variables examined in this study. The effect of parameters on the specific surface area, total pore volume and burn-out rate of activated carbon was studied,and the influential parameters of methylene blue adsorption value were identified employing analysis of variance. The optimum conditions for maximum methylene blue adsorption value were: activation temperature = 900 ℃, activation time = 29.05 min and CO_2 flow rate = 1.8 L·min(~-1). The activated carbon produced under optimum conditions was characterized by BET, FTIR and SEM. The adsorption behavior on congo red was studied. The effect of parameters on the adsorbent dosage, temperature, PH and initial congo red concentration was investigated. The adsorption properties of the activated carbon were investigated by kinetics. The equilibrium removal rate and maximum adsorption capacity reaches up to 94.72%, 234 mg·g-1,respectively when initial congo red concentration is 200 mg·L~(-1) under adsorbent dosage(0.8 g · L~(-1)),temperature(30℃), PH7.     

Protein-derived nitrogen and sulfur co-doped carbon for efficient adsorptive removal of heavy metals

A nitrogen and sulfur co-doped carbon has been synthesized employing egg white as a sustainable protein-rich precursor. According to CHNS elemental analysis, N, S and O heteroatoms accounted for mass fractions of 3.66%, 2.28% and 19.29% respectively, and the types of surface functionalities were further characterized by FT-IR and XPS measurements. Although the carbon possessed a smaller surface area (815 m²·g^-1) compared to a commercial activated carbon (1100 m²·g^-1), its adsorption capacity towards Co²⁺ reached 320.3 mg·g^-1, which was over 8 times higher compared to the limited 34.0 mg·g^-1 over the activate carbon. Furthermore, the carbon was found to be an efficient adsorbent towards a series of metal ions including VO²⁺, Cr³⁺, Ni²⁺, Cu²⁺ and Cd²⁺. Combined with its environmental merits, the protein derived carbon may be a promising candidate for heavy metal pollution control.     

Hydrothermal synthesis of zeolitic material from circulating fluidized bed combustion fly ash for the highly efficient removal of lead from aqueous solution

The utilization of coal fly ash derived from circulating fluidized bed combustion(CFBFA) still faces great challenges because of its unique characteristics. In this study, a zeolitic material with Na-P1 zeolite as the main phase was successfully synthesized via a hydrothermal method by using CFBFA as the raw material.The effects of hydrothermal temperature, time, and added CTAB amount on the characterizations of synthesized materials were investigated by XRD, SEM, and XPS. The properties of the ...     

Mechanism and kinetics study on removal of Iron from phosphoric acid by cation exchange resin

Iron element is one of the main impurities in wet-process phosphoric acid and it has a significant impact on the subsequent phosphorus chemical products. This paper studied the feasibility of using Sinco-430 cation exchange resin for iron removal from phosphoric acid. The specific surface area and the total exchange capacity of resin were 8.91 m~2·g~(-1) and 5.18 mmol·g~(-1), respectively. The sorption mechanism was determined by FTIR and XPS and the results indicated that iron was combined with-SO_3 H in resin. The removal process was studied as a function of temperature, H_3 PO_4 content and mass ratio between resin and solution. The unit mass of resin to remove iron was 0.058 g·g~(-1) resin when the operating parameters were T = 50 ℃, H_3 PO_4 content = 27.61 wt%and S/L = 0.1, respectively. Kinetics study demonstrated that pseudo-second-order reaction model fits this study best and the calculated activation energy of overall reaction is 29.10 kJ·mol~(-1). The overall reaction process was mainly controlled by pore diffusion.     

FeS2@TiO2 nanorods as high-performance anode for sodium ion battery

Sodium-ion battery (SIB) is an ideal device that could replace lithium-ion battery (LIB) in grid-scale energy storage system for power because of the low cost and rich reserve of raw material. The key challenge lies in developing electrode materials enabling reversible Na⁺ insertion/desertion and fast reaction kinetics. Herein, a core-shell structure, FeS₂ nanoparticles encapsulated in biphase TiO₂ shell (FeS₂@TiO₂), is developed towards the improvement of sodium storage. The diphase TiO₂ coating supplies abundant anatase/rutile interface and oxygen vacancies which will enhance the charge transfer, and avoid severe volume variation of FeS₂ caused by the Na⁺ insertion. The FeS₂ core will deliver high theoretical capacity through its conversion reaction mechanism. Consequently, the FeS₂@TiO₂ nanorods display notable performance as anode for SIBs including long-term cycling performance (637.8 mA·h·g^-1 at 0.2 A·g^-1 after 300 cycles, 374.9 mA·h·g^-1 at 5.0 A·g^-1 after 600 cycles) and outstanding rate capability (222.2 mA·h·g^-1 at 10 A·g^-1). Furthermore, the synthesized FeS₂@TiO₂ demonstrates significant pseudocapacitive behavior which accounts for 90.7% of the Na⁺ storage, and efficiently boosts the rate capability. This work provides a new pathway to fabricate anode material with an optimized structure and crystal phase for SIBs.     

Modification and sequential treatment of EU-1 zeolite in mild alkali and alkaline-acid conditions

EU-1 zeolites were sequentially treated with low-concentration sodium carbonate(Na_2CO_3) and hydrochloric acid(HCl) solutions.The obtained samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),N_2 adsorption/desorption,temperature programmed desorption of NH_3(NH_3-TPD),solid state~(27)A1 nuclear magnetic resonance(~(27)A1 NMR),and the catalytic performances of the treated samples were tested in the xylene isomerization reaction.The results showed that the external surface area and mesoporous volume of the sample sequentially treated with 0.05 mol·L~(-1) Na_2CO_3 and 0.1 mol·L~(-1) HCl solutions reached73.9 m~2·g~(-1) and 0.162 cm~3·g~(-1),respectively.The catalytic performances of EU-1 zeolites were significantly improved,that the activity of the probe reaction increased from 23.03%to 23.61%and the selectivity increased from85.09%to 87.14%compared with those of parent sample.Furthermore,it was found that only amorphous silica and alumina species was dissolved during the post-treatment process,but the framework structure and the acidic properties of EU-1 zeolite remained intact.     

新型遇油膨胀橡胶的制备与性能研究

以甲基丙烯酸十八酯(SMA)、甲基丙烯酸丁酯(BMA)和甲基丙烯酸甲酯(MMA)为单体,采用悬浮聚合法合成了高吸油树脂SMA-g-BMA和SMA-g-BMA-g-MMA。分别以吸油树脂和SMA单体为改性剂,以三元乙丙橡胶(EPDM)为基胶,制备了遇油膨胀橡胶(OSR)。结果表明,用吸油树脂制备的遇油膨胀橡胶力学性能优于用SMA单体制备的遇油膨胀橡胶。当吸油树脂用量为20份且SMA∶BMA=1∶2时,OSR拉伸强度为15.2MPa。对汽油、柴油、机油和甲苯的吸收率分别为330%,326%,250%和502%。     

Conversion of Malaysian low-rank coal to mesoporous activated carbon: Structure characterization and adsorption properties

Malaysian Selantik low-rank coal (SC) was used as a precursor to prepare a form of mesoporous activated carbon (SC-AC) with greater surface area (SA) via a microwave induced KOH-activation method. The characteristics of the SC and SC-AC were evaluated by the iodine number, ash content, bulk density, and moisture content. The structure and surface characterization was carried out using pore structure analysis (BET), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), elemental analysis (CHNS), thermogravimetric analysis (TGA), and determination of the point of zero charge (pH_PZC). These results signify a mesoporous structure of SC-AC with an increase of ca. 1160 times (BET SA=1094.3 m²·g^-1) as compared with raw SC without activation (BET SA=1.23 m²·g^-1). The adsorptive properties of the SC-AC with methylene blue (MB) was carried out at variable adsorbent dose (0.2-1.6 g·L^-1), solution pH (2-12), initial MB concentrations (25-400 mg·L^-1), and contact time (0-290 min) using batch mode operation. The kinetic profiles follow pseudo-second order kinetics and the equilibrium uptake of MB conforms to the Langmuir model with a maximum monolayer adsorption capacity of 491.7 mg·g^-1 at 303 K. Thermodynamic functions revealed a spontaneous endothermic adsorption process. The mechanism of adsorption included mainly electrostatic attractions, hydrogen bonding interaction, and π-π stacking interaction. This work shows that Malaysian Selantik low-rank coal is a promising precursor for the production of low-cost and efficient mesoporous activated carbon with substantive surface area.     

甲基丙烯酸接枝改性玉米芯对Cd2+的吸附及机理

以甲基丙烯酸为单体、高锰酸钾/浓硫酸为引发体系对玉米芯进行接枝改性,成功引入羧基官能团,结合扫描电镜、红外光谱和zeta电位等分析手段研究了吸附条件对玉米芯吸附Cd²⁺过程的影响及其吸附机理。结果表明,吸附过程符合Langmuir模型和准二级动力学方程,改性玉米芯对Cd²⁺的吸附主要是化学吸附过程,吸附速率是颗粒内扩散速率和膜扩散速率共同影响的结果;在pH 7、投加量为5 g·L^-1、温度为30℃、吸附时间为6 h的条件下,接枝改性玉米芯和原玉米芯对Cd²⁺的最大吸附容量分别为28.00 mg·g^-1和5.96 mg·g^-1,提高了近4倍;玉米芯对Cd²⁺的吸附是一个自发的吸热反应,温度越高,自发程度越大;接枝改性玉米芯对Cd²⁺的吸附过程中,参与反应的主要官能团有羧基、羟基、酰胺基和甲基等,吸附Cd²⁺后的接枝改性玉米芯表面出现褶皱和白色小颗粒,孔隙消失,电负性增大。     

原位合成的介孔TiO2-B/锐钛微粒:改善的锂离子电池阳极材料（英文）

Mesoporous TiO2-B/anatase microparticles have been in-situ synthesized from K2Ti2O5 without template. The TiO2-B phase around the particle surface accelerates the diffusion of charges through the interface, while the anatase phase in the core maintains the capacity stability. The heterojunction interface between the main polymorph of anatase and the trace of TiO2-B exhibits promising lithium ion battery performance. This trace of 5%(by mass) TiO2-B determined by Raman spectra brings the first discharge capacity of this material to 247 mA·h·g?1, giving 20%improvement com-pared to the anatase counterpart. Stability testing at 1 C reveals that the capacity maintains at 171 mA·h·g?1, which is better than 162 mA·h·g?1 for single phase anatase or 159 mA·h·g?1 for TiO2-B. The mesoporous TiO2-B/anatase microparticles also show superior rate performance with 100 mA·h·g?1 at 40 C, increased by nearly 25%as compared to pure anatase. This opens a possibility of a general design route, which can be applied to other metal oxide electrode materials for rechargeable batteries and supercapacitors.     

Spray-drying assisted layer-structured H2TiO3 ion sieve synthesis and lithium adsorption performance

A spray-drying assisted solid-state method to prepare spherical layer-structured H₂TiO₃ ion sieve (LSTIS) particles is reported herein. The effects of synthesis parameters (calcination temperature, calcination time, and the lithium-titanium molar ratio) on adsorption–desorption performance (the delithiation ratio, titanium dissolution loss, and the adsorption capacity) were investigated. The as-prepared LSTIS exhibited an equilibrium adsorption capacity of 30.08 mg·g^-1 (average of 25.85 mg·g^-1 over 5 cycles) and ultra-low titanium dissolution loss of less than 0.12% (average of 0.086% over 5 cycles). The LSTIS showed excellent selectivity toward Li⁺ in Na⁺, K⁺, Mg²⁺, and Ca²⁺ coexisting saline solutions where its adsorption capacity reached 27.45 mg·g^-1 and the separation factors of Li⁺ over the coexisting cations exceeded 100. The data suggests that the LSTIS is promising to competitively enrich Li⁺ from saline solutions.     

Pre-sodiation strategy for superior sodium storage batteries

The irreversible consumption of sodium in the initial several cycles greatly led to the attenuation of capacity, which caused the low initial coulombic efficiency (ICE) and obvious poor cycle stability. Pre-sodiation can effectively improve the electrochemical performance by compensating the capacity loss in the initial cycle. Here, carbon-coated sodium-pretreated iron disulfide (NaFeS₂@C) has been synthesized through conventional chemical method and used in sodium metal battery as a cathode material. The calculated density of states (DOS) of NaFeS₂@C is higher, which implies enhanced electron mobility and improved cycle reversibility. Because of the highly reversible conversion reaction and the compensation of irreversible capacity loss during the initial cycle, the Na/NaFeS₂@C battery achieves ultra-high initial coulombic efficiency (96.7%) and remarkable capacity (751 mA·h·g^-1 at 0.1 A·g^-1). In addition, highly reversible electrochemical reactions and ultra-thin NaF-rich solid electrolyte interphase (SEI) also benefit for the electrochemical performance, even at high current density of 100 A·g^-1, it still exhibits a reversible capacity of 136 mA·h·g^-1, and 343 mA·h·g^-1 after 2500 cycles at 5.0 A·g^-1. This work aims to bring up new insights to improve the ICE and stability of sodium metal batteries.     

Three-dimensional oxygen-doped porous graphene: Sodium chloride-template preparation,structural characterization and supercapacitor performances

Supercapacitor is a new type of energy storage device, which has the advantages of high-power property and long cycle life. In this study, three-dimensional graphene (3D-GN) with oxygen doping and porous structure was prepared from graphene oxide (GO) by an inexpensive sodium chloride (NaCl) template, as a promising electrode material for the supercapacitor. The structure, morphology, specific surface area, pore size, of the sample were characterized by XRD, SEM, TEM and BET techniques. The electrochemical performances of the sample were tested by CV and CDC techniques. The 3D-GE product is a three-dimensional nano material with hierarchical porous structures, its specific surface area is much larger than that of routine stacked graphene (GN), and it contains a large number of mesoporous and macropores, a small amount of micropores. The capacitance characteristics of the 3D-GN electrode material are excellent, showing high specific capacitance (173.5 F·g^-1 at 1 A·g^-1), good rate performance (109.2 F·g^-1 at 8 A·g^-1) and long cycle life (88% capacitance retention after 10,000 cycles at 8 A·g^-1)     

Regulatable pervaporation performance of Zn-MOFs/polydimethylsiloxane mixed matrix pervaporation membranes

Pervaporation (PV) is an emerging separation technique for liquid mixture. Mixed matrix membranes (MMMs) often demonstrate trade-off relationship between separation factor and flux. In this study, by changing the organic linkers (2-methyl imidazolate, imidazole-2-carboxaldehyde, 2-ethyl imidazolate), ZIF-8, ZIF-90 and MAF-6 were prepared and filled in polydimethylsiloxane (PDMS) membranes for dealcoholization of 5% (mass) n-butanol solution, and the membranes properties and pervaporation performances were adjusted. Compared with the pure PDMS membrane, the addition of ZIF-8 resulted in a 9% increase in flux (1136 g·m^-2·h^-1) and a 22.5% increase in separation factor (28.3), displaying anti-trade-off effect. For the MAF-6/PDMS MMMs (2.0% mass loading), the pervaporation separation index (PSI) and separation factor were 32347 g·m^-2·h^-1 and 58.6 respectively (increased by 34% and 154% in contrast with that of the pure PDMS membrane), and the corresponding permeation flux was 552 g·m^-2·h^-1, presenting great potential in the removal butanol from water. It was deduced that the large aperture size combined with moderate hydrophobicity of metal-organic frameworks (MOFs) favor the concurrent increase in permeability and selectivity.     

Facile synthesis of spinel LiNi0.5Mn1.5O4 as 5.0 V-class high-voltage cathode materials for Li-ion batteries

LiNi_0.5Mn_1.5O₄ and LiMn₂O₄ with novel spinel morphology were synthesized by a hydrothermal and post-calcination process. The synthesized LiMn₂O₄ particles (5-10 μm) are uniform hexahedron, while the LiNi_0.5Mn_1.5O₄ has spindle-like morphology with the long axis 10-15 μm, short axis 5-8 μm. Both LiMn₂O₄ and LiNi_0.5Mn_1.5O₄ show high capacity when used as cathode materials for Li-ion batteries. In the voltage range of 2.5-5.5 V at room temperature, the LiNi_0.5Mn_1.5O₄ has a high discharge capacity of 135.04 mA·h·g^-1 at 20 mA·g^-1, which is close to 147 mA·h·g^-1 (theoretical capacity of LiNi_0.5Mn_1.5O₄). The discharge capacity of LiMn₂O₄ is 131.08 mA·h·g^-1 at 20 mA·g^-1. Moreover, the LiNi_0.5Mn_1.5O₄ shows a higher capacity retention (76%) compared to that of LiMn₂O₄ (61%) after 50 cycles. The morphology and structure of LiMn₂O₄ and LiNi_0.5Mn_1.5O₄ are well kept even after cycling as demonstrated by SEM and XRD on cycled LiMn₂O₄ and LiNi_0.5Mn_1.5O₄ electrodes.     

培养基优化以促进超高浓度发酵生产乙醇(英文)

An optimal medium (300 g·L-1 initial glucose) comprising 6.3 mmol·L-1 Mg2+, 5.0 mmol·L-1 Ca2+, 15.0 g·L-1 peptone and 21.5 g·L-1 yeast extract was determined by uniform design to improve very high gravity (VHG) ethanol fermentation, showing over 30% increase in final ethanol (from 13.1% to 17.1%, by volume), 29% decrease in fermentation time (from 84 to 60 h), 80% increase in biomass formation and 26% increase in glucose utilization. Experiments also revealed physiological aspects linked to the fermentation enhancements. Compared to the control, trehalose in the cells grown in optimal fermentation medium increased 17.9-, 2.8-, 1.9-, 1.8- and 1.9-fold at the fermentation time of 12, 24, 36, 48 and 60 h, respectively. Its sharp rise at the early stage of fermentation when there was a considerable osmotic stress suggested that trehalose played an important role in promoting fermentation. Meanwhile, at the identical five fermentation time, the plasma membrane ATPase activity of the cells grown in optimal medium was 2.3, 1.8, 1.6, 1.5 and 1.3 times that of the control, respectively. Their disparities in enzymatic activity became wider when the glucose levels were dramatically changed for ethanol production, suggesting this enzyme also contributed to the fermentation improvements. Thus, medium optimization for VHG ethanol fermentation was found to trigger the increased yeast trehalose accumulation and plasma membrane ATPase activity.     

Porous polymer microsphere functionalized with benzimidazolium based ionic liquids as effective solid catalysts for esterification

To prepare polymer supported ionic liquids (PSILs) as effective catalysts for esterification, the free radical suspension copolymerization of vinylbenzyl chloride (VBC, monomer), styrene (St, monomer) and divinylbenzene (DVB, crosslinker) with the addition of n-heptane (porogen) was carried out for the fabrication of the porous polymer (PVD) microsphere as support, followed by the immobilization of sulfonic acid-functionalized ionic liquids by the successive treatment of benzimidazole (BIm), 1,3-propane sultone and sulfuric acid (H₂SO₄) or trifluoromethanesulfonic acid (CF₃SO₃H). The effects of the compositions of DVB and n-heptane on the internal structure of the polymer supports were investigated, and it was found that the support with 40 wt% DVB and 60 wt% n-heptane (with relative to the monomer) could endow the final PSILs with the relatively optimal catalytic performance. The preliminary experiment in the batch reactor indicated that PSILs herein exhibited higher catalytic activities than commercial Amberlyst 46 resin for the esterification of propanoic acid (PROAc) with n-propanol (PROOH). Consequently, the optimal PSILs catalyst, PVD-[Bim-SO₃H]HSO₄, was selected for further study in the batch reactive distillation column because of low cost and its ease of preparation. The yield of propyl ropionate (PROPRO) could reach up to 97.78% at the optimized conditions of PROOH/PROAc molar ratio (2:1) and catalyst dosage (2.0 wt%). The investigation of the reaction kinetic manifested that the calculated results of second order pseudo-homogeneous kinetic model were in good agreement with experimental values. The pre-exponential factor and activation energy were 4.12×10⁷ L·mol^-1·min^-1 and 60.57 kJ·mol^-1, respectively. It is worth noting that the PSILs catalyst could be simply recovered and reused with relatively satisfactory decrease in the catalytic activity, which made it an environmental friendly and promising catalyst in the industrial application.