基于喹啉单元的荧光传感器用于Fe3+及F-的可逆检测

荧光检测具有操作简单、选择性高、成本低等优点,是一种很有前途的金属离子检测方法。本文基于喹啉合成了新型荧光传感器,实现了对三价铁离子(Fe³⁺)和氟离子(F^-)的高灵敏、高特异性检测。传感器D1可与Fe³⁺络合,引起荧光猝灭;当存在F^-时,猝灭作用减弱,D1荧光恢复,由此可进行Fe³⁺和F^-的连续识别。D1对Fe³⁺和F^-的检出限分别为0.07μM和0.13μM,是Fe³⁺和F^-分析检测的有力工具。     

木质素磺酸钙-石墨烯复合量子点的制备及性能

木质素磺酸盐是造纸工业主要副产物之一,本文利用木质素磺酸钙和柠檬酸为原料通过绿色简便的原位反应制备木质素磺酸钙/石墨烯复合量子点,利用荧光光谱、紫外可见光谱和透射电镜等研究了复合量子点的光学性能、结构模型和对金属离子的选择性吸附性能,结果表明该复合量子点的荧光强度是石墨烯量子点的4倍多,并且复合量子点可以选择性识别Fe³⁺,在10～500μmol/L范围内,Fe³⁺的浓度与复合量子点溶液的荧光强度有良好的线性关系,可应用于Fe³⁺的检测。此荧光探针制备简便,成本低廉,检测铁离子速度快,准确性高,选择性好,在离子检测方面有潜在的应用价值。     

“开关型”碳量子点在同型半胱氨酸检测中的应用

以柠檬酸和尿素为原料,采用一步水热法制备碳量子点,以此作为荧光探针,建立一种简单、高效、性价比高的检测同型半胱氨酸(Hcy)的方法。Fe³⁺对碳量子点的荧光具有猝灭效应,能够使碳量子点的荧光值减弱,结构中含有巯基的药物可以与Fe³⁺发生络合,从而使荧光值恢复。按照此种方法进行对药物含量的检测,结果表明,Fe³⁺溶液、同型半胱氨酸的三者混合体系在pH值为6、Fe³⁺溶液和碳量子点作用时间为10 min时荧光猝灭效果最佳,同型半胱氨酸再加入12 min后对碳量子点溶液的荧光效应恢复最好,同型半胱氨酸浓度在2.5×10^-4～2×10^-3 mol/L范围内,与荧光值F呈现良好的线性关系(R²=0.994 6)。采用该方法测定了同型半胱氨酸含量,加标回收率为97.1%～103%,检出限为6.21μmol/L。相较于高效液相来说,该方法成本更低,更加简单可行,使用更为方便,结果满意。     

氮掺杂碳点的制备及其在Fe3+检测中的应用

以含氮的三羟甲基氨基甲烷为碳源,采用水热法制备了水溶性良好的氮掺杂碳点(N-CDs)。通过荧光光谱、紫外-可见光谱、傅里叶红外光谱、场发射透射电镜和X射线光电子能谱,对制备的N-CDs的结构和光学性质进行了表征,研究了p H和含盐量对N-CDs荧光性能的影响,并以N-CDs为荧光探针,检测水中的Fe³⁺。结果表明,制备的N-CDs分散性好,水溶性好,尺寸均一,平均粒径为6.1 nm,具有较好的p H稳定性和耐盐性。Fe³⁺对制备的N-CDs具有荧光猝灭效应,在0.1～80μmol·L^-1的Fe³⁺浓度范围内,N-CDs荧光强度的降低与Fe³⁺浓度具有良好的线性关系,线性方程为ΔF=1.0001C+18.9646,相关系数R²为0.9932。制备的N-CDs具有制备简单、成本低、检测灵敏度高等优点,可作为荧光探针用于检测水中微量的Fe³⁺,具有潜在的应用前景。     

碳量子点/Fe3+复合材料用于生物传感检测抗坏血酸

利用碱木质素为原料,在浓硫酸与浓硝酸环境中,先进行超声处理,随后转移至反应釜中,180℃水热反应12h,制备碳量子点（CDs）,并采用多种测试手段对其结构及形貌进行了表征。通过CDs溶液与Fe³⁺溶液相互作用,制备得到CDs/Fe³⁺复合材料。利用紫外光谱及荧光光谱研究了CDs及CDs/Fe³⁺复合材料的光学性能,发现CDs具有优异的荧光性能,其荧光量子产率达17.3%（硫酸喹啉为参比物质）,而CDs/Fe³⁺复合材料荧光猝灭明显。将CDs/Fe³⁺复合材料应用于人体内不同生物活性分子检测,发现CDs/Fe³⁺复合材料对抗坏血酸（AA）具有特异性识别,且在0~200μmol/L及200~350μmol/L范围内,AA浓度与CDs/Fe³⁺复合材料的荧光强度呈现良好的线性关系,同时具有优异的选择识别性,可应用于生物体内AA的检测,在生物传感方面具有潜在的应用价值。     

热解法合成生物质碳量子点及其在Fe3+检测中的应用

本文通过一步热解香蕉皮并优化反应条件，合成了一种具有蓝色荧光发射的碳量子点(CDs)，其荧光量子产率约为8.9%。该碳量子点的最佳激发波长为270 nm，最佳发射波长为423.4 nm。利用TEM、XRD、XPS、FTIR、紫外及荧光光谱仪等手段表征了其形貌和结构。通过离子选择性测试发现Fe³⁺能较好的猝灭其荧光强度，在0～160μmol·L^-1的浓度范围内，碳点的荧光猝灭效率F/F₀与Fe³⁺浓度c之间呈现良好的线性关系，其线性回归方程为F/F₀=-0.00113c+1.00151，相关系数R²为0.99833，检出限为12.6μmol·L^-1。对广州市花都区天马河河水进行Fe³⁺加标检测，回收率达到102.84%～112.11%，相对标准偏差RSD约为2.5%～3.2%。     

N、S共掺杂煤基碳量子点的电化学氧化法制备及用于Fe3+检测

异质元素掺杂可以有效改善碳量子点的荧光性能，被广泛应用于碳量子点的改性。选取昭通褐煤为碳源，氯化钠溶液为电解液，硫脲为助剂，采用电化学氧化法完成N、S共掺杂碳量子点(N,S-CQD)的制备，荧光量子产率为1.60%。采用多种表征方法研究了N,S-CQD的结构、组成和光学特性。首先在结构组成方面，N,S-CQD是一类球形颗粒，尺寸分布均匀，平均粒径为1.66nm，其中主要存在C、O元素，还存在部分N和S元素；其次在光学性质方面，N,S-CQD在紫外光区吸收明显，荧光分析显示其最佳激发波长为280nm，最佳发射波长为313nm。最后基于Fe³⁺对N,S-CQD的荧光猝灭效应，将N,S-CQD应用于痕量Fe³⁺的检测，N,S-CQD对15～150μmol/L浓度范围内Fe³⁺的检测表现出较高的选择性和灵敏度，通过计算得出最低检出限L=1.22μmol/L，表明N,S-CQD可应用于痕量Fe³⁺的检测。     

芦苇碳量子点的微波法制备及对Co2+的检测

以芦苇为碳源，以3-氨丙基三甲氧基硅烷(APS)为修饰剂，600 W的条件下微波消解反应2 min,用微波法合成的荧光碳量子点(APS-CQDs)稳定性好、灵敏度高。将合成的碳量子点溶液在电压为600 V,狭缝为10 nm的条件下，在465 nm可见光下呈现出淡绿色荧光。基于Co²⁺对芦苇碳量子点具有良好的荧光猝灭效应，建立了一种简单且快速检测Co²⁺的新方法。实验结果表明，对于0.01～0.1 mmol/L的Co²⁺对芦苇碳量子点的荧光猝灭程度呈现最好的线性关系(R²=0.991 1),检出限可达0.118μmol/L。     

基于百香果壳的荧光碳量子点的制备及对Fe3+的检测

以百香果壳为原材料,采用水热法合成荧光碳量子点(CQDs),考察了碳量子点(CQDs)对Fe³⁺的检测效果。利用透射电子显微镜(TEM)、X射线衍射(XRD)、红外光谱仪(FT-IR)、紫外-可见吸收光谱仪、荧光光谱仪等对碳量子点(CQDs)的形貌、结构、基团、光谱特性等进行了表征。结果显示,合成的碳量子点形貌和分散性良好,尺寸约为7 nm。在435 nm的激发波长下,其发射峰位于512 nm处。在反应温度为120℃,反应时间为12 h时,所得到的碳量子点的性能最好。Fe³⁺对CQDs荧光有明显的猝灭现象,而其他金属离子的加入不会改变CQDs的荧光强度及发射峰位置,说明合成的CQDs可以实现对Fe³⁺的特异性检测。     

蓝色荧光碳点的制备及检测、防伪应用

以柠檬酸钠为碳源、氨水为氮源,采用一步水热法制备了氮掺杂碳点(NCDs),对其制备条件进行了优化.采用荧光光谱仪、TEM、AFM、XPS及FTIR对制备的NCDs进行了表征,并探索了NCDs在Fe3+检测及荧光防伪中的应用.结果表明,NCDs的最优制备条件为柠檬酸钠浓度为0.1 mol/L、氨水浓度为1.8 mol/L、反应温度为200℃、反应时间6 h、装载体积25 mL.在最优条件下制备的NCDs的荧光为典型的非激发波长依赖型,最佳激发波长为343 nm,最佳发射波长为443 nm,荧光量子产率可达54.9％.NCDs为球形结构,平均粒径为4.96 nm,碳核为类石墨烯结构且其表面含有—NH2、—OH及—COOH.NCDs的荧光可被Fe3+选择性猝灭,且荧光猝灭程度与Fe3+浓度在0.1～87.5μmol/L范围内线性关系良好,检测限为50 nmol/L.此外,将NCDs配制成荧光墨水,利用喷墨打印机打印出的图案整体饱满、边缘细节清晰具有很强的可识别性.     

直接甲醇液流燃料电池的二维两相模型

直接甲醇燃料电池(DMFC)的阴极水淹、甲醇渗透及贵金属催化剂的成本问题是DMFC商业化的主要障碍。直接甲醇液流燃料电池(DMRFC)使用Fe³⁺/Fe²⁺氧化还原电对取代DMFC阴极,克服了阴极的水淹、甲醇渗透和电池成本等问题。使用Comsol Multiphysics4.2a模拟软件,建立了一个DMRFC二维两相模型来预测电池性能,模拟结果显示增加阳极催化层厚度、减少阳极扩散层厚度和提高Fe³⁺浓度有利于提高电池的性能,但当阳极催化层厚度和甲醇浓度分别大于5×10^-5 m和1.41 mol/L时,电池性能并不能显著提高。     

Kinetics and mass transfer effects in the oxidation of ferrous sulfate over doped active carbon catalysts

Ferric sulfate is used in water purification. The oxidation of ferrous sulfate, FeSO₄, to ferric sulfate in acidic aqueous solutions of H₂SO₄ over finely dispersed active carbon particles was studied in a vigorously stirred batch reactor. Molecular oxygen was used as the oxidation agent and two kinds of catalysts were utilized: active carbon, doped active carbon. Both active carbon and doped active carbon catalysts enhanced the oxidation rate considerably.

Systematic kinetic experiments were carried out at the temperature and pressure ranges of 60–100°C and 4–10 bar, respectively. The results revealed that both non-catalytic and catalytic oxidation of Fe²⁺ take place simultaneously. The experimental data were fitted to rate equations, which were based on a plausible reaction mechanism: adsorption of dissolved oxygen on active carbon, electron transfer from Fe²⁺ ions to adsorbed oxygen and formation of surface hydroxyls. A comparison of the Fe²⁺ concentrations predicted by the kinetic model with the experimentally observed concentrations indicated that the mechanistic rate equations were able to describe the intrinsic oxidation kinetics of Fe²⁺ over pure active carbon and doped active carbon catalysts.     

Simplistic hydrothermal synthesis approach for fabricating photoluminescent carbon dots and its potential application as an efficient sensor probe for toxic lead(II) ion detection

The past decade has witnessed a variety of members of the carbon family along with exposure of carbon dots due to their magnificent properties in sensing, bioimaging, catalytic applications, biomedical fields, and so on. Herein, we report the simple hydrothermal method to fabricate photoluminescent doped carbon quantum dots for the detection of noxious lead(II) ions. Lead(II) ion is very venomous for both the environment and human health for which its detection is demanded area in the research field. The as-prepared carbon dots show excellent photostability, low toxicity and significant photoluminescence properties along with good water solubility. Along with these properties, carbon dots have a quantum yield of approximately 15%. In the practical field of application, these carbon dots have been used as sensing probes for the detection of lead(II) ions with a detection limit of 60 nmol·L^–1. The fluorescence intensity of carbon dots was remarkably quenched in the presence of the lead(II) ion selectively among all the tested metal ions. Furthermore, we have studied the Stern–Volmer relationship for lead(II) quenching along with the explanation of the probable quenching mechanism. Ability of the doped carbon dots in heavy metal ions sensing in an environmental sample was demonstrated.     

Fe(Ⅱ)活化过硫酸盐氧化破解剩余污泥

采用 Fe(Ⅱ)活化过硫酸盐,产生强氧化性硫酸根自由基(SO₄^-·),以污泥释放的溶解性COD(SCOD)、相对疏水性(RH)和污泥比阻(SRF)为表征,考察了SO₄^-·氧化破解剩余污泥强化脱水的影响因素,并解析了机理。结果表明:当初始pH为4.5,n(S₂O₈^2-)=2.2 mmol·(g VSS)^-1,n(Fe²⁺)=1.32 mmol·(g VSS)^-1,常温下反应3 h后,SCOD由66.5 mg·L^-1增加到472.3 mg·L^-1,RH由26.9%升高到41.1%,SRF由24.9×10⁸ S²·g^-1降低至4.5×10⁸ S²·g^-1;在此基础上利用响应面法,根据Box-Benhnken中心组合试验设计,以SRF为响应指标,优化条件为pH 4.27,n(S₂O₈^2-)=2.6 mmol·(g VSS)^-1,n(Fe²⁺)=1.59 mmol·(g VSS)^-1时,SRF为3.8×10⁸ S²·g^-1,泥饼含水率为72.7%。镜检发现,破解后污泥变为颗粒碎片状;傅里叶红外光谱显示污泥表面官能团对应的特征吸收峰强度有一定程度的减弱;热重分析表明无明显物理吸附水失重区。证实了在SO₄^-·作用下,污泥菌胶团结构破坏,溶胞释放了有机物,使表观疏水性更强,与水结合力明显减弱,脱水性得到了较大提高,有利于污泥减量化应用。     

Fe3+在A2O工艺缺氧区的转化规律及其对污泥絮凝性的影响

为了研究铁元素对A²O工艺污泥絮凝性的影响,考察Fe³⁺在污泥上清液、胞外聚合物（extracellular polymeric substances,EPS）与底泥（Pellet）中的分布和迁移转化规律,结合三维荧光光谱（3D-EEM）、原子吸收和X射线衍射仪（XRD）分析Fe的存在形态和结构特征,揭示Fe³⁺与微生物代谢产物的作用机制,探索Fe³⁺对脱氮除磷效率的影响。结果表明：低浓度Fe³⁺（<10 mg·L^-1）能够提高COD和TN去除率,促进微生物活性,增强污泥生物絮凝性;高浓度Fe³⁺（10~40 mg·L^-1）则抑制微生物活性,使EPS总量升高,污泥絮体脱稳,LB、TB层PN/PS是影响污泥絮凝性的关键因素;Fe³⁺的投加强化生物除磷效率,当Fe³⁺浓度为40 mg·L^-1时,TP去除率为93%。Fe³⁺在污泥混合液中的分布规律为TB>上清液>LB>SMP,Fe³⁺在生物体内富集累积,能够改变EPS各层的组分。     

基于邻二氮菲-Fe2+的间接显色光度法检测片剂中的卡托普利

卡托普利还原Fe³⁺,Fe²⁺与邻二氮杂菲显色物在510 nm处有最大吸收,吸光度(A)与卡托普利浓度有相关性。结果表明,卡托普利浓度(c)在1×10^-6~1×10^-4 mol/L范围内与A呈良好的线性关系:y=0.006 4c+0.005 5,相关系数(r)=0.997 6,检测限为9.37×10^-7 mol/L。该方法用于片剂卡托普利测定,结果满意。     

酰胺键为间隔基的吡啶双子表面活性剂合成及性能

以乙二胺、1-溴代烷、氯乙酰氯和吡啶为原料,经卤代、酰胺化和季铵化反应合成了系列酰胺键为间隔基的吡啶双子表面活性剂。目标产物合成条件:超声波(40kHz,100W)辅助反应,反应温度60℃,反应时间5h。用 FTIR、¹H NMR、¹³C NMR对目标产物进行了结构表征,对目标产物的临界胶束浓度(cmc)、乳化性、泡沫稳定性和杀菌性能进行了考察。实验结果表明,该系列产物的临界胶束浓度cmc 为1.4×10^-2～2.3×10^-5mol/L,具有较好的乳化性和稳泡性。在浓度为100mg/L时,烷基链碳原子数为8的表面活性剂对大肠杆菌和枯草芽孢杆菌的抑菌效果最好。     

Catalytic behavior of the Fe/Fe system in the electro-Fenton degradation of the antimicrobial chlorophene

The catalytic behavior of the Fe³⁺/Fe²⁺ system in the electro-Fenton degradation of the antimicrobial drug chlorophene has been studied considering four undivided electrolytic cells, where a Pt or boron-doped diamond (BDD) anode and a carbon felt or O₂-diffusion cathode have been used. Chlorophene electrolyses have been carried out at pH 3.0 under current control, with 0.05 M Na₂SO₄ as supporting electrolyte and Fe³⁺ as catalyst. In these processes the drug is oxidized with hydroxyl radical (OH) formed both at the anode from water oxidation and in the medium from electrochemically generated Fenton's reagent (Fe²⁺ + H₂O₂, both of them generated at the cathode). The catalytic behavior of the Fe³⁺/Fe²⁺ system mainly depends on the cathode tested. In the cells with an O₂-diffusion cathode, H₂O₂ is largely accumulated and the Fe³⁺ content remains practically unchanged. Under these conditions, the chlorophene decay is enhanced by increasing the initial Fe³⁺ concentration, because this leads to a higher quantity of Fe²⁺ regenerated at the cathode and, subsequently, to a greater OH production from Fenton's reaction. In contrast, when the carbon felt cathode is used, H₂O₂ is electrogenerated in small extent, whereas Fe²⁺ is largely accumulated because the regeneration of this ion from Fe³⁺ reduction at the cathode is much faster than its oxidation to Fe³⁺ at the anode. In this case, an Fe³⁺ concentration as low as 0.2 mM is required to obtain the maximum OH generation rate, yielding the quickest chlorophene removal. Chlorophene is poorly mineralized in the Pt/O₂ diffusion cell because the final Fe³⁺–oxalate complexes are difficult to oxidize with OH. These complexes are completely destroyed using a BDD anode at high current thanks to the great amount of OH generated on its surface. Total mineralization is also achieved in the Pt/carbon felt and BDD/carbon felt cells with 0.2 mM Fe³⁺, because oxalic acid and its Fe²⁺ complexes are directly oxidized with OH in the medium. Comparing the four cells, the highest oxidizing power regarding total mineralization is attained for the BDD/carbon felt cell at high current due to the simultaneous destruction of oxalic acid at the BDD surface and in the bulk solution.