阴/阳离子表面活性剂自发囊泡的氧化还原响应行为研究

利用一种对氧化还原具有刺激响应的阴离子表面活性剂十二烷基硒丙基硫酸钠(SDSePS)与阳离子表面活性剂十二烷基三甲基溴化铵(DTAB)复配形成SDSePS/DTAB自发囊泡,探究了该囊泡的氧化还原可逆响应行为。结果表明,在H_2O_2的作用下,SDSePS分子中二价硒醚基团(-Se-)可以被氧化成四价硒亚砜基团(-Se=O),SDSePS/DTAB自发囊泡被瓦解成球状胶束;在Na_2SO_3的作用下,四价硒亚砜基团被还原成二价硒醚基团,SDSePS/DTAB自发囊泡再次形成;在H2O2和Na2SO3的交替作用下,SDSePS/DTAB自发囊泡可以在胶束和囊泡两种状态下可逆氧化还原循环至少10次,还原再生的SDSePS/DTAB自发囊泡的平均半径稳定在115～130 nm。     

壳聚糖的接枝改性及其CO2/N2响应乳化性能研究

通过化学反应将甲基丙烯酸二甲氨基乙酯(DMAEMA)接入壳聚糖(CTS)的分子结构中,获得改性产物CTS-gDMAEMA。使用红外光谱和核磁氢谱对其进行了结构表征。向CTS-g-DMAEMA的聚集体分散液中依次通入CO_2和N_2后,其外观形态、透光率和电导率发生了明显的循环变化,证实了CTS-g-DMAEMA的CO_2/N_2刺激响应性。水-液体石蜡的乳化实验证明,与原料CTS相比,CTS-g-DMAEMA具有更好的稳定乳液的能力;并且在CO_2/N_2作用下,由CTS-g-DMAEMA制备的乳液可以发生破乳和再乳化的循环。     

CO_2/N_2-光双重刺激响应型表面活性剂的合成及性能研究

利用7-羟基香豆素、1,10-二溴癸烷和盐酸二甲胺合成了一种双重刺激响应型的表面活性剂7-(氧-10-二甲氨基-癸基)-香豆素(7-OAC)。通入CO_2或N_2,可实现表面活性的"开"与"关",也可利用其结构中的香豆素基团在300 nm以上紫外光下进行光二聚反应。通过质谱、核磁等表征了其结构,测定了其表面性能及N_2/CO_2和双重光刺激响应性能。     

CO_2/N_2-光双重刺激响应型表面活性剂的合成及性能研究

利用7-羟基香豆素、1,10-二溴癸烷和盐酸二甲胺合成了一种双重刺激响应型的表面活性剂7-(氧-10-二甲氨基-癸基)-香豆素(7-OAC)。通入CO_2或N_2,可实现表面活性的"开"与"关",也可利用其结构中的香豆素基团在300 nm以上紫外光下进行光二聚反应。通过质谱、核磁等表征了其结构,测定了其表面性能及N_2/CO_2和双重光刺激响应性能。     

g-C_3N_4-RGO-TiO_2光催化还原U(Ⅵ)的实验研究

以尿素为氮源、TiO_2为钛源,引入还原氧化石墨烯,采用超声合成法制备了氮化碳-还原氧化石墨烯-二氧化钛(g-C_3N_4-RGO-TiO_2)三元异质Z型光催化剂,在可见光照射下光催化还原低浓度含铀水溶液。结果表明,当pH=6,催化剂浓度为0.2 g/L,光照强度为600 W时,铀的光催化还原率最高达到99%。U(Ⅵ)被还原为U(Ⅳ),除了光生电子(e^-)的还原作用外,还原基团CO_2-)的还原作用外,还原基团CO_2^-·也参与U(Ⅵ)的还原。     

CO2/N2开关微乳液及其油污洗涤和分离性能

采用等摩尔的十二烷基苯磺酸钠与N-十二烷基-N,N-二甲基叔胺为主乳化剂,正丁醇为助乳化剂,正庚烷为油相,制得O/W型微乳液。在CO_2/N_2交替作用下,可实现微乳液-相分离-微乳液的可逆转换;原始微乳液与复原微乳液半径分别为(10.89±0.21)和(11.50±0.47)nm。该微乳液对多孔固体和织物表面烃类矿物油的洗油率分别为99.13%±0.32%和98.30%±0.28%,对油砂表面原油的洗油率为54.52%±0.25%。活性物质量分数相等时,微乳稀释液对织物表面油性记号笔渍的去污力是市售洗衣粉的1.90倍;而微乳原液的去污力是市售洗衣粉的2.02倍。洗后含油废液通入CO_2可迅速实现油水分层,分离油相后的残余水相经阴、阳离子交换树脂和活性炭常规处理,COD和TOC分别为40.62和17.51 mg/L,符合GB 18918-2002中一级水排放标准(COD≤100 mg/L,TOC≤20 mg/L)。     

非共价改性纳米颗粒稳定Pickering乳液的制备及可逆调控

用具有氧化还原活性分子乙酰基二茂铁吖嗪(Fc⁺A)对磁性纳米颗粒Fe₃O₄@SiO₂进行非共价疏水改性，将改性颗粒作为乳化剂制备Pickering乳液。通过TEM、SEM、FTIR、XRD、接触角测量、光学显微镜等对纳米颗粒及Pickering乳液的结构、形貌和性能进行表征。结果表明：制备的核壳结构纳米颗粒粒径为150 nm左右，分散均匀；Fc⁺A成功修饰到纳米颗粒表面，且随Fc⁺A浓度的增加，改性颗粒的接触角明显增大；Fc⁺A浓度为12.5 mmol/L，乳化剂浓度为0.3%(质量)，油水比为4∶6，搅拌速率为10000 r/min，得到的Pickering乳液具有良好的稳定性。而且，所得乳液具双重响应性，通过氧化还原和磁场可实现对乳液稳定性的可逆调控。     

一个基于主客体作用的超两亲分子自组装体系的构筑及其光调控

合成了含偶氮苯和胆甾醇基团的分子Azo Chol,在主客体作用的驱动下与α-环糊精(α-CD)形成了一个超两亲分子Azo Chol/α-CD。利用透射电镜(TEM)、原子力显微镜(AFM)、激光共聚焦电子显微镜(CLSM)等实验手段证明了该超两亲分子在水溶液中自组装形成囊泡结构。偶氮苯基团在光照刺激下可以发生顺反异构的可逆变化,导致超两亲分子的解体和再次形成,进一步引起体系发生囊泡解体与再形成的可逆转变。这种具有光刺激响应的超分子结构的转变在智能材料领域可能具有潜在应用价值。     

酸碱调控的二茂铁咪唑电化学开关

本文设计合成了一系列具有共轭结构的二茂铁咪唑衍生物,它们在质子的作用下呈现显著的光谱、核磁及电化学响应.在中性(或碱性)环境中,其氧化还原波处于低电位,表现为分子关的状态;在酸性环境中,其氧化还原波处于高电位,表现为分子开的状态;通过酸碱的调控作用其氧化还原波可以在高、低电位之间可逆转换,能够作为一类新型的电化学开关器件.     

水汽对膜法捕集CO2的影响

为了考察水汽单独存在及与SO_2或颗粒物共存时对聚酰亚胺(PI)分离膜和聚丙烯(PP)吸收膜捕集CO_2性能的影响规律,利用自行搭建的CO_2膜捕集试验台进行了研究。结果表明:在试验条件下,当烟气的相对湿度达到90%时,PI分离膜对CO_2/N_2的分离因子略有上升,但渗透速率下降,PP膜的CO_2吸收效率下降7%,经N_2反吹后,PI膜和PP膜的捕集效率均能得到恢复;水汽与SO_2共存,PI分离膜的CO_2/N_2分离因子和渗透速率分别下降5.64%和24.54%,PP吸收膜脱除效率下降18%,但经N_2反吹及膜丝实验前后红外测试表明水汽与SO_2共存对PI膜和PP膜性能造成的影响都是可逆的;水汽与颗粒物共存时,PI分离膜的CO_2/N_2分离因子和渗透速率分别下降39.79%和49.82%,PP吸收膜脱除效率下降18.9%,通过N_2反吹分析水汽和颗粒物共存对PI分离膜和PP膜造成的影响不可逆。     

Stimuli-responsive emulsions:Recent advances and potential applications

Responsive emulsions are the emulsions that can be reversibly switched on-demand between "stable"and "unstable" by environmental stimulus or trigger,which allows a simple and effective adjustment approach to achieve emulsification and demulsification.In recent years,stimuli-responsive emulsions acting as smart soft material are received considerable attention with the advantages of simple manip-ulation,good reversibility,low cost,easy treatment,and little effect on the system.In this paper,the recent research progress of emulsions that can respond to external stimuli,including pH,light,magnetic field,CO2/N2 and dual responsive are reviewed.Also,the potential applications based on responsive emulsion are discussed,such as catalytic reactions,heavy oil recovery,polymer particles synthesis and optical sensor,aiming to summarize the latest achievements and put forward the possible development trends of responsive emulsions.     

CO2/N2 separation using supported ionic liquid membranes with green and cost-effective [Choline][Pro]/PEG200 mixtures

The high price and toxicity of ionic liquids(ILs) have limited the design and application of supported ionic liquid membranes(SILMs) for CO_2 separation in both academic and industrial fields. In this work, [Choline][Pro]/polyethylene glycol 200(PEG200) mixtures were selected to prepare novel SILMs because of their green and costeffective characterization, and the CO_2/N_2 separation with the prepared SILMs was investigated experimentally at temperatures from 308.15 to 343.15 K. The temperature effect on the permeability, solubility and diffusivity of CO_2 was modeled with the Arrhenius equation. A competitive performance of the prepared SILMs was observed with high CO_2 permeability ranged in 343.3–1798.6 barrer and high CO_2/N_2 selectivity from 7.9 to 34.8.It was also found that the CO_2 permeability increased 3 times by decreasing the viscosity of liquids from 370 to38 m Pa·s. In addition, the inherent mechanism behind the significant permeability enhancement was revealed based on the diffusion-reaction theory, i.e. with the addition of PEG200, the overall resistance was substantially decreased and the SILMs process was switched from diffusion-control to reaction-control.     

十二烷基四甲基胍CO2开关表面活性剂的性能研究

合成并表征了十二烷基四甲基胍（DTMG）,研究了其可逆性能。结果表明,DTMG能与CO2形成离子化合物,可以选用CO2为开关控制其溶液的表面活性。向DTMG的溶液中通入CO2或加热CO2饱和的DTMG溶液,溶液的碱性以及表面张力等性质能可逆变化。该表面活性剂形成的乳液和泡沫亦能通过CO2在稳定与不稳定之间可逆变化。另外,通过简单的指示剂酚酞,由溶液的状态能够很容易用肉眼观察到：红色代表无表面活性,而无色则指示具有表面活性。该表面活性剂在工业领域具有重要的应用价值。     

The carbon nanoparticles grafted with copolymers of styrene and spiropyran with reversibly photoswitchable fluorescence

A kind of photoswitchable nanoparticles which are the fluorescent carbon nanoparticles grafted with the copolymers of styrene and spiropyran (f-CNP-g-poly(St-co-SP) is reported. The f-CNP-g-poly(St-co-SP) not only feature the reversibly photoswitchable fluorescence, but also have good processability. Their fluorescence could be reversibly switched between blue-green and red by using ultraviolet/visible light irradiation. Furthermore, they could be readily processed into nanofibers with reversibly photoswitchable fluorescence by electrospinning. They can be potentially applied in fabricating microdevice, optical switching, information storage, anti-counterfeiting as well as biological imaging.     

Recovery and Recycling of CO2/N2‐Switchable Anionic Surfactants in Emulsions

To develop a mild, effective, and clean strategy for recovery and recycling of anionic surfactants in CO₂/N₂‐switchable emulsions, a CO₂/N₂‐switchable anionic surfactant, which is a combination of dodecyl seleninic acid (DSA) and N,N,N′,N′‐tetramethyl‐1,2‐ethylenediamine (TMEDA), here referred to as DSA–TMEDA, was used to stabilize an oil‐in‐water (O/W) emulsion. Upon stimulation with CO₂, DSA–TMEDA was switched off to form insoluble DSA and the water‐soluble TMEDA bicarbonate. Upon N₂ bubbling and heating, the OFF state of DSA–TMEDA was restored to the surfactant of DSA–TMEDA. In this manner, O/W emulsions stabilized by DSA–TMEDA can be switched reversibly between demulsification (phase separation) and re‐emulsification (recovered emulsion) by triggering with CO₂/N₂ over ten times. After breakage of the emulsion, nearly all of the OFF state surfactant could be separated conveniently away from the oil phase, thus facilitating recovery and recycling of the surfactant afterward in emulsifying oil. No obvious adverse changes in the dispersed oil particles size and the relative stability of the regenerated emulsions were observed over five cycles, and the surfactant loss can be neglected during the recycling.     

N_2O跨临界二级蒸气压缩制冷循环及回热特性

为解决CO2跨临界循环能效低、排气压力高的问题,将天然工质N2O用于跨临界循环,建立了相应的理论模型,比较了CO2和N2O用于二级蒸气压缩跨临界循环的性能,并分析了回热效率对于CO2和N2O系统能效Ccop和最优高压侧排气压力的影响。结果表明:N2O用于二级蒸气压缩跨临界制冷循环中的综合性能要优于CO2,在所选定的工况范围内,N2O的Ccop值比CO2最多提高13.3%,最优高压侧排气压力最多降低17.7%。回热效率对于CO2和N2O系统的最优高压侧排气压力几乎没有影响,回热循环对于CO2二级压缩跨临界系统的能效提升更为有利。     

负载型K2CO3/Al2O3二氧化碳吸收剂的碳酸化反应特性

引言 全球变暖已经成为一个备受关注的环境问题.据预测,如不采取积极的温室气体减排措施,从现在起到2100年,全球近地面平均气温将继续升高1.4～5.8℃[1].CO2是主要的温室气体,而我国燃煤电厂是CO2排放量最大、最集中的化石燃料燃烧场所.因此研究和开发适用于燃煤电厂的CO2减排技术至关重要.     

Redox-catalytic correlations in oxidised copper-ceria CO-PROX catalysts

Four nanostructured oxidised copper-cerium catalysts prepared by two different methods (impregnation of ceria and coprecipitation of the two components within reverse microemulsions) with varying copper loadings have been examined with the aim of establishing correlations between redox and catalytic properties for preferential oxidation of CO in H₂-rich streams. The analysis is based on ex situ TPR examination both with H₂ or CO as well as operando spectroscopic exploration by DRIFTS and XANES, additionally complemented by conventional catalytic tests. The results reveal redox promoting effects on copper oxide reduction and allow establishing a model of the catalytic behaviour of this type of catalysts which can provide keys to control their CO-PROX catalytic properties.     

Rh2O3/monoclinic CePO4 composite catalysts for N2O decomposition and CO oxidation

CePO_4(in particular,monoclinic CePO_4)has been rarely used to make supported catalysts.Herein,monoclinic CePO_4 nanoparticles were prepared by calcining hexagonal CePO_4 nanorods(prepared by precipitation)in air at 900℃.Monoclinic CePO_4 nanowires were prepared by calcining hexagonal CePO_4 nanowires(prepared by hydrothermal synthesis at 150℃)in air at 900℃.Both monoclinic CePO_4 materials were used to support Rh_2O_3 by impregnation using Rh(NO_3)_3 as a precursor(followed by calcination).The catalytic performance of Rh_2O_3/monoclinic CePO_4 composite materials in N_2O decomposition and CO oxidation was investigated.It was found that Rh_2O_3 supported on monoclinic CePO_4 nanowires was much more active than Rh_2O_3 supported on monoclinic CePO_4 nanoparticles.The stability of catalysts as a function of reaction time on stream was studied in both reactions.The influence of co-fed CO_2,O_2,and H_2O on the catalytic activity in N_2O decomposition was also studied.These catalysts were characterized by employing N_2 adsorption–desorption,ICP-OES,XRD,TEM,XPS,H_2-TPR,O_2-TPD,and CO_2-TPD.The correlation between physicochemical properties and catalytic properties was discussed.