接力识别Al^(3+)及F^(-)的偶氮类荧光探针合成与应用

以6-氨基间甲酚和1-萘酚为原料,合成了2-(2-羟基-4-甲基苯偶氮)-1-萘酚(探针NA-M),通过^(1)HNMR、^(13)CNMR、FTIR、HRMS表征了其结构。测试了探针NA-M对Al^(3+)的选择性识别性能及其与Al^(3+)形成的络合物(NA-M+Al^(3+))对F^(-)的选择性识别性能,推测了探针NA-M与Al^(3+)和F^(-)间的作用机制。考察了探针NA-M在实际样品中的应用。结果表明,在pH=7.4、V(甲醇)∶V(N-2-羟乙基哌嗪-N'-2-乙磺酸)=9∶1的溶剂中,探针NA-M与Al^(3+)在590 nm处发生显著的荧光增强作用,并对Al^(3+)的识别表现出高选择性、抗金属离子干扰性和良好的灵敏度(检测限为8.4×10^(-7)mol/L),Al^(3+)与探针NA-M形成了配位比为1∶2的NA-M+Al^(3+);NA-M+Al^(3+)在F^(-)加入后发生显著的荧光猝灭现象,F^(-)可以捕获NA-M+Al^(3+)中的Al^(3+),从而引起荧光变化。NA-M+Al^(3+)对F^(-)的识别也显示出高选择性和良好的抗其他阴离子干扰能力和灵敏度(检测限为9.5×10^(-7)mol/L);在体系pH为5~10时,探针NA-M识别Al^(3+)及F^(-)表现出良好的效果,交替加入Al^(3+)和F^(-)可引起其荧光强度的可逆变化,探针NA-M可以通过荧光信号的“关-开-关”转变,用于接力识别Al^(3+)和F^(-)。在实际样品的检测中,Al^(3+)的回收率在98.8%~107.0%之间,相对标准偏差(RSD)为2.6%~4.3%;F^(-)的回收率为97.8%~101.4%,RSD为1.4%~2.3%。

F^(-)掺杂ZrO_(2)粉体的水热合成及光催化性研究

采用水热合成法以HF为矿化剂制备了具有较高光催化性的F-掺杂ZrO_(2)纳米材料,系统研究F-对ZrO_(2)纳米粉体相组成、形貌、晶体生长及光催化性能的影响。结果表明:F^(-)的引入促进四方相ZrO_(2)向单斜相的相转化。矿化剂HF掺杂浓度的增加,促进单斜相ZrO_(2)初始生长基元晶粒的生长以及二次颗粒的长大。F^(-)在ZrO_(2){001}晶面上的吸附使ZrO_(2)的初始棒状晶粒趋向于沿[001]方向生长,同时也促进棒状晶粒在{001}晶面定向附生形成纺锤状三维颗粒。在60 min的光照条件下,所有F^(-)掺杂的ZrO_(2)粉末对甲基橙的降解效率均可达到80%以上。0.04 F/ZrO_(2)催化剂的光催化性能最高,在60 min内甲基橙的降解率可达91.7%。

La/Al天然沸石对水中F^(-)的吸附及再生

以天然沸石为原料,制备La/Al负载天然沸石,用于水中F^(-)的吸附,并对其吸附动力学、等温吸附性能、再生能力和吸附机理进行探讨。结果表明,该吸附剂对F^(-)的吸附符合拟二级动力学模型和Langmuir模型,在298K温度条件下,理论最大吸附量为19.2mg/g。pH的升高不利于F^(-)的吸附。Cl^(-)、NO_(3)^(-)对F^(-)的吸附影响较小,而HCO_(3)^(-)和H_(2)PO_(4)^(-)的存在不利于F^(-)的吸附。在0.5mol/L NaOH条件下,经过5次循环再生,吸附剂对F^(-)的吸附量降低16.7%。SEM、BET、EDS-mapping和XPS分析表明,F^(-)的吸附机理主要为配体交换。

F^(*)-空间中关于β-次线性函数的探讨

在F^(*)-空间中引入β-次线性函数的概念,研究F^(*)-空间中的β-凸集和S-β-凸函数,并得到了几个重要结果.

Fixed-Bed Column Adsorption Modeling of MnO4- Ions from Acidic Aqueous Solutions on Activated Carbons Prepared with the Biomass

Activated carbons calcined at 400˚C and 600˚C (AC-400 and AC-600), prepared using palm nuts, collected in the town of Franceville in Gabon, were used to study the dynamic adsorption of MnO4- ions in acidic media on fixed bed column and on the kinetic modeling of experimental data of breakthrough curves of MnO4- ions obtained. Results on the adsorption of MnO4- ions in fixed-bed dynamics obtained on AC-400 and AC-600 adsorbents beds indicated that the AC-400 bed appears to be the most efficient in removing MnO4- ions in acidic media. Indeed, the adsorbed amounts, the adsorbed capacities at saturation and the elimination percentage of MnO4- ions obtained with AC-400 (31.24 mg;52.06 mg·g-1 and 41.65% respectively) were higher compared to those obtained with AC-600 (9.87 mg;16.45 mg·g-1 and 17.79% respectively). The breakthrough curves kinetic modeling revealed that the Thomas model and the pseudo-first-order kinetic model were the most suitable models to describe the adsorption of MnO4- ions on adsorbents studied in our experimental conditions. The results of the intraparticle diffusion model showed that intraparticle diffusion was involved in the adsorption mechanism of MnO4- ions on investigated adsorbents and was not the limiting step and the only process controlling MnO4- ions adsorption. In contrast to AC-400, the intraparticle diffusion on AC-600 bed plays an important role in the adsorption mechanism of MnO4- ions.

La@SiO_(2)负载天然沸石对F^(-)的吸附研究

以天然沸石为载体,制备了La@SiO_(2)负载天然沸石材料La@Si-NZ,并用于水中氟离子(F^(-))的吸附,对材料的吸附动力学、等温吸附性能、再生能力和吸附机理进行了探究。结果表明,La@Si-NZ对F-的吸附,符合拟二级动力学模型和Langmuir模型,在298K下,理论最大吸附量为14.2 mg·g^(-1)。动态吸附中,经过5次循环再生后,La@Si-NZ对F-的吸附量降低了10%。

Adsorption properties of CFBC ash-cement pastes as compared with PCC fly ash-cement pastes

Circulating fluidized bed combustion （CFBC） ash can be potentially used as supplementary cementitious materials for concrete production due to its desirable pozzolanic activity. The adsorption properties of CFBC ash-cement pastes were studied, and ordinary pulverized coal combustion （PCC） fly ash-cement pastes were used as control. The water-adsorption and superplasticizer （SP）-adsorption properties of the pastes were evaluated by water demand and UV-visible absorption spectroscopy respectively. The results show that CFBC ash-cement system has greater compressive strength as compared with PCC fly ash-cement system at a given curing age, although the water demand of the former is significantly higher than that of the latter. CFBC ash-cement pastes possess higher adsorption ability of aliphatic SP than PCC fly ash-cement pastes and the adsorption amount increases with an increase in ash replacement ratio. CFBC ash- cement pastes exhibit lower workability with higher slump loss. It is concluded that CFBC ash can be potentially used as supplementary cementitious material in concrete production, but the mix design of CFBC ash concrete needs to be appropriately adjusted. It is suggested that CFBC ash is used for the production of the concrete needing low flowability.

Adsorption and flotation mechanism of a ketoxime-dithiocarbonate surfactant to chalcopyrite

The adsorption mechanism of O-isopropyl-S-[2-(hydroxyimino) propyl] dithiocarbonate ester(IPXPO) to chalcopyrite was investigated by using contact angle, in-situ atomic force microscopy(in-situ AFM), cyclic voltammetry(CV) and X-ray photoelectron spectroscopy(XPS). The results of contact angle and in-situ AFM demonstrated that IPXPO adsorbed on chalcopyrite increases surface hydrophobicity and roughness. It was found by CV experiments that a layer passive film was formed. The results of XPS spectra further revealed that the thiol S atom, oxime N atom, and O atom in the IPXPO molecule might react with copper atoms to form Cu-S, Cu-N, and Cu-O bonds, respectively. An artificial mixed minerals flotation test indicated that under the condition of pH=6.79 and IPXPO initial concentration 5×10^(-5)mol/L, the flotation recovery of chalcopyrite reached about 90%, while for pyrite only 25%, suggesting that IPXPO is an excellent collector for flotation separation and enrichment of chalcopyrite.

DFT Investigation of O_2 Adsorption on Si(001)-(2×2×1):H

A novel model was developed to theoretically evaluate the 02 adsorption on H-terminated Si（001）-（2×2×1） surface. The periodic boundary condition, the ultrasoft pseudopotentials technique based on density functional theory （DFT） with generalized gradient approxi,natior, （GGA） functional were applied in our ab initio calculations. By analyzing bonding energy oil site, the favourable adsorption site was determined. The calculations also predicted that the adsorption products should be Si=O and H2O. This theoretical study snpported the reaction mechanism provided by Kovalev et al, The results were also a base for further investigation of some more complex systems such as the oxida.tion on porous silicon surface.

水杨醛肼二腙类聚集诱导发光染料合成及对F^(-)的检测

研究开发了1个具有ESIPT+AIE性能的分子5-甲基水杨醛肼二腙(5-Me-SAA),并用于识别检测F^(-)。基于ESIPT性能,5-Me-SAA的稀溶液呈现烯醇式(E)和酮式(K)的双发射,K式发射峰随溶剂极性的增大而下降。5-Me-SAA在四氢呋喃稀溶液中处于自由分散状态,荧光发射较弱;在纯水中形成聚集体,荧光增强22倍,表现出AIE性能。此外,5-Me-SAA可通过裸眼和荧光双通道快速选择性识别F^(-),且响应灵敏,检测限为0.64μmol·L^(-1)。进一步利用核磁共振氢谱探究了探针与F^(-)的作用机理,结果表明在F^(-)作用下,探针的酚羟基发生去质子化,光学性质随之改变。

Theoretical Investigation of Adsorption Effects of Granisetron Anticancer Drug over BN(7,7-7) Nanotube as a Factor of Drug Delivery: a DFT Study

In the present work, the interaction between drug Granisetron(GRS) and BN(7,7-7) nanotube by density functional theory(DFT) calculations in the solvent water has been investigated. The non-bonded interaction effects of the molecule GRS with BN(7,7-7) nanotube on chemical shift tensors, natural charge and electronic properties such as the energy gap between HOMO and LUMO, global hardness, electronegativity and electronic chemical potential have been also detected. The natural bond orbital(NBO) analysis suggested that charge transfer depended between GRS and nanotube and induces a dipole moment in the complex. Then, the possibility of the use of BN(7,7-7) nanotube for GRS delivery to the diseased cells has been established.

Adsorption Isotherms of Quercetin and Catechin Compounds on Quercetin-MIP

A molecular imprinted polymer（MIP） was prepared with quereetin as the template and methaerylie acid（MAA） as the functional monomer. Aeetonitrile and methanol were used as the porogen with ethylene glycol dimethaerylate （EGDMA） as the erosslinker and 2,2＇-azobis （ isobutyronitrile ） （ AIBN ） as the initiator. The experimental parameters of the equilibrium isotherms were estimated via linear and nonlinear regression analyses. The linear equadon as the functions of the adsorption concentration of the single compound in its solution and the competitive adsorption of the single compound in its mixed compounds solution was then expressed, and the adsorption equilibrium data were correlated to Langmuir and Freundlich isotherm models. The mixture compounds show competitive adsorption on the specific binding sites of quereetin-MIP. Furthermore, the competitive Langmnir isotherms were applied to the mixture compounds. The adsorption concentrations of quercetin, （＋）eatechin（＋C）, and （-）epieateehin（EC） on the quercetin molecular imprinted polymer were compared. The quercetin-imprinted polymer shows extraordinarily higher adsorption ability for quercetin than for the two eateehin compounds that were also assessed.

阵列电极研究F^(-)对铜在5%Na_(2)SO_(4)溶液中腐蚀电化学行为的影响

采用阵列电极技术、扫描电子显微镜、自腐蚀电位、极化曲线和电化学阻抗等电化学方法研究F-对铜在5%Na2SO4溶液中腐蚀电化学行为的影响。结果表明:F-使铜表面的腐蚀电流密度增大,自腐蚀电位负移,电化学阻抗降低,铜表面各区域的自腐蚀电位标准方差由21.08增加到28.31,阻抗标准方差由1.431增加到2.071。F-的存在使铜表面的腐蚀产物膜层的形貌及结构发生明显变化,腐蚀产物膜层由均匀致密分布的颗粒状转变为凹凸不平、疏松的多坑状。说明F-能加剧铜的腐蚀并破坏铜表面腐蚀产物膜层,加剧局部微区腐蚀的发生,铜腐蚀趋于不均匀。

高选择性、高灵敏的咔唑衍生物F^(-)荧光增强型探针

以4-羟基咔唑为原料,合成了一种含硅氧基团的咔唑衍生物(HCTC),通过核磁共振氢谱和高分辨质谱对其结构进行了表征,并对探针的F^(-)检测性能进行了研究。结果表明:HCTC能够利用F^(-)对硅氧键的高亲核性的特异性进攻,表现出对F^(-)的化学反应型荧光探针特性;当加入F^(-)以后,该探针溶液在波长433 nm处出现新的荧光发射峰,并伴随轻微的红移现象,而加入其他常见的阴离子都不能引起类似的现象,HCTC对F^(-)的检测限相对较低(0.21μmol/L);将HCTC探针制备成荧光试纸,它能够对含少量乙腈的水溶液中的F^(-)具有荧光检测性能。HCTC是一种高选择性、高灵敏度的F^(-)荧光增强型探针。

基于掺杂型石墨烯量子点构建关—开型电化学发光传感器连续检测Fe^(3+)和F^(-)

目的:研究石墨烯量子点的电化学发光性能。方法:制备发光强度高、性能稳定的氮硫掺杂石墨烯量子点(NS-GQDs),并构建关—开型电化学发光(ECL)传感器以实现对Fe^(3+)和F^(-)的连续检测。结果:在0.1~460.0μmol/L范围内,Fe^(3+)浓度与ECL猝灭值呈良好的线性关系,检出限为0.028μmol/L;在1~5600μmol/L范围内,F^(-)浓度与ECL恢复值呈良好的线性关系,检出限为0.62μmol/L。结论:NS-GQDs ECL信号的猝灭和恢复具有较好的可逆性,可应用于饮用水中Fe^(3+)和F^(-)的连续检测。

F^(-)在方解石表面的吸附及其对方解石表面性质的影响

氟元素主要存在于磷矿和萤石等矿物中,这些矿物中都伴生有方解石脉石矿物,在浮选分离的弱酸条件下,矿物表面的F^(-)会部分溶出并吸附到矿物表面,从而影响矿物表面性质。本文研究了F^(-)在方解石表面的吸附及其对方解石表面性质的影响机理。结果表明,在矿浆pH值为5.5时,F^(-)以化学吸附的方式吸附在方解石表面,随着吸附时间的增加吸附量逐渐增加,90 min时方解石对F^(-)的吸附达到平衡。在油酸钠(NaOL)为捕收剂时,F^(-)的存在会降低方解石表面的疏水性。通过Zeta电位测试、溶液化学计算和X射线光电子能谱仪(XPS)分析表明,F^(-)会和方解石表面的Ca^(2+)反应生成CaF_(2)沉淀,占据方解石表面的Ca位点,降低NaOL在方解石表面的吸附量。

3D layer-by-layer amorphous MoS_(x) assembled from[Mo_(3)S_(13)]^(2-)clusters for efficient removal of tetracycline:Synergy of adsorption and photo-assisted PMS activation

Peroxymonosulfate(PMS)activation and photocatalysis are effective technologies to remove organic pollutants,but the adsorption effect of the catalyst is usually unheeded in degradation process.Herein,a bifunctional catalyst of amorphous MoS_(x)(a-MoS_(x))with 3D layer-by-layer superstructure was synthesized by assembling basic active units[Mo_(3)S_(13)]^(2-)of MoS_(2).The large interlayer spacing and high exposure of active sites render a-MoS_(x)to have excellent synergy of adsorption and photo-assisted PMS activation for tetracycline(TC)degradation.Experiments and DFT calculation show that TC can be efficiently enriched on a-MoS_(x)by pore filling,π-πinteraction,hydrogen bonding and high adsorption energy.Subsequently,PMS can be quickly activated through electron transfer with a-MoS_(x),resulting in high TC degradation efficiency of 96.6%within 20 min.In addition,the synergistic mechanism of adsorption and photo-assisted PMS activation was explored,and the degradation pathway of TC was expounded.This work is inspirational for constructing bifunctional catalysts with superior synergistic adsorption and catalytic capabilities to remove refractory organic pollutants in water.

Synthesis and Adsorption Property of Two Polymeric Adsorbents with Pendent Ether Bonds

Two polymeric adsorbents, poly(methyl p-vinylbenzyl ether) and poly(phenyl p-vinylbenzyl ether), were synthesized from chloromethylated polystyrene. Their adsorption property for phenol in hexane solution was investigated. The results showed that the two adsorbents adsorb phenol from hexane solution through hydrogen-bonding and π-π stacking interaction.

Insights into the enhanced structure stability and electrochemical performance of Ti^(4+)/F^(-) co-doped P2-Na_(0.67)Ni_(0.33)Mn_(0.67)O_(2) cathodes for sodium ion batteries at high voltage

P2-Na_(0.67)N_(i0.33)Mn_(0.67)O_(2)is considered as a promising cathode material for sodium-ion battery (SIBs)because of its high capacity and discharge potential.However,its practical use is limited by Na^(+)/vacancy ordering and P2-O2 phase transition.Herein,a Ti^(4+)/F^(-) co-doping strategy is developed to address these issues.The optimal P2-Na_(0.67)Ni_(0.33)Mn_(0.37)Ti_(0.3)O_(1.9)F_(0.1) exhibits much enhanced sodium storage performance in the high voltage range of 2.0–4.4 V,including a cycling stability of 77.2%over 300cycles at a rate of 2 C and a high-rate capability of 87.7 m Ah g^(-1) at 6 C.Moreover,the P2-Na_(0.67)Ni_(0.33)Mn_(0.37)Ti_(0.3)O_(1.9)F_(0.1) delivers reversible capacities of 82.7 and 128.1 m Ah g^(-1) at-10 and 50℃ at a rate of 2 C,respectively.The capacity retentions over 200 cycles at-10℃ is 94.2%,implying more opportunity for practical application.In-situ X-ray diffraction analysis reveals that both P2-O2 phase transitions and Na^(+)/vacancy ordering is suppressed by Ti^(4+)/F^(-) co-doping,which resulting in fast Na^(+) diffusion and stable phase structure.The hard carbon//P2-Na_(0.67)Ni_(0.33)Mn_(0.37)Ti_(0.3)O_(1.9)F_(0.1) full cell exhibits a high energy density of 310.2 Wh kg^(-1) and remarkable cyclability with 82.1%retention after 300 cycles at 1 C in the voltage range of 1.5–4.2 V.These results demonstrate that the co-doping Ti^(4+)/F^(-) is a promising strategy to improve the electrochemical properties of P2-Na_(0.67)Ni_(0.33)Mn_(0.67)O_(2),providing a facile tactic to develop high performance cathode materials for SIBs.

浅析离子色谱法测定生活饮用水中F^(-)、CL^(-)、NO_(3)^(-)和SO_(4)^(2-)影响因素的控制

本文采用离子色谱法同时测定生活饮用水中F^(-)、CL^(-)、NO_(3)^(-)和SO_(4)^(2-)等阴离子含量,通过系列的实验,分析了该方法的线性关系和精密度,探讨了使用该方法同时测定饮用水中F^(-)、CL^(-)、NO_(3)^(-)和SO_(4)^(2-)时有关淋洗液浓度、流速、分离柱等条件对实验的影响。结果表明,在设立的实验条件下,该方法具有简单、快速与准确的特点,应用此方法测定各离子的线性相关系数r≥0.9995,各离子重复测定的相对标准偏差RSD<2%。