Solid-phase extraction of iron(III) with an ion-imprinted functionalized silica gel sorbent prepared by a surface imprinting technique

A new Fe(III)-imprinted amino-functionalized silica gel sorbent was prepared by a surface imprinting technique for selective solid-phase extraction (SPE) of Fe(III) prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Compared with non-imprinted polymer particles, the ion-imprinted polymers (IIPs) had higher selectivity and adsorption capacity for Fe(III). The maximum static adsorption capacity of the ion-imprinted and non-imprinted sorbent for Fe(III) was 25.21 and 5.10 mg g⁻¹, respectively. The largest selectivity coefficient of the Fe(III)-imprinted sorbent for Fe(III) in the presence of Cr(III) was over 450. The relatively selective factor (α_r) values of Fe(III)/Cr(III) were 49.9 and 42.4, which were greater than 1. The distribution ratio (D) values of Fe(III)-imprinted polymers for Fe(III) were greatly larger than that for Cr(III). The detection limit (3σ) was 0.34 μg L⁻¹. The relative standard deviation of the method was 1.50% for eight replicate determinations. The method was validated by analyzing two certified reference materials (GBW 08301 and GBW 08303), the results obtained is in good agreement with standard values. The developed method was also successfully applied to the determination of trace iron in plants and water samples with satisfactory results.     

Robust Amino-Functionalized Mesoporous Silica Hollow Spheres Templated by CO2 Bubbles

Hollow-structured mesoporous silica has wide applications in catalysis and drug delivery due to its high surface area, large hollow space, and short diffusion mesochannels. However, the synthesis of hollow structures usually requires sacrificial templates, leading to increased production costs and environmental problems. Here, for the first time, amino-functionalized mesoporous silica hollow spheres were synthesized by using CO₂ gaseous bubbles as templates. The assembly of anionic surfactants, co-structure directing agents, and inorganic silica precursors around CO₂ bubbles formed the mesoporous silica shells. The hollow silica spheres, 200–400 nm in size with 20–30 nm spherical shell thickness, had abundant amine groups on the surface of the mesopores, indicating excellent applications for CO₂ capture, Knoevenagel condensation reaction, and the controlled release of Drugs.     

The fabrication of a nanoscale polyoxometalate based magnetic adsorbent and its selective adsorption on cationic dyes

Amino group-functionalized Fe₃O₄ is loaded on a coordination complex-modified polyoxometalate nanoparticle. In this composite material, Fe₃O₄ and coordination complex-modified polyoxometalate are connected with intense hydrogen bonds as suggested by FTIR. This composite material exhibits excellent methylene blue (MB) adsorption, with adsorption capacity of 175.5 mg g^?1. It also possesses selective separation ability between cationic and anionic dye molecules. In binary solution of MB and methyl orange (MO), MB adsorption efficiency reaches 75%, but it exhibits almost no effect on the adsorption of methyl orange. The saturation magnetization value of this composite material is 18.89 emu g^?1, allowing magnetic separation, which facilitates the recycle and reuse of this composite adsorbent.     

氨基功能化纳米复合材料对磷酸盐的吸附研究

合成了4种氨基(乙二胺(EDA), 二乙烯三胺(DETA), 三乙烯四胺(TETA)和四乙烯五胺(TEPA))功能化纳米复合材料(NH₂-NCMs, 分别命名为EDA-NCMs, DETA-NCMs, TETA-NCMs和TEPA-NCMs). 采用FTIR(傅立叶变换红外光谱分析), TG/DTG(热重差热分析), XPS(X-射线光电子能谱分析)等手段对其进行了表征, 并考察了其对水中磷酸盐的吸附性能. 结果表明: 溶液pH对其吸附性能影响较大, 在pH为2.5的条件下, 4种吸附剂对磷酸盐的吸附效果最佳; 在5 min内即可达到平衡吸附量的90%; 4种吸附剂对磷酸盐的吸附均符合Langmuir等温吸附模型; 吸附行为均符合准二级速率模型; 吸附反应为自发进行的放热反应和熵减的过程; 推测其吸附机理以静电作用力为主. 4种吸附剂用于磷酸盐含量为50 mg/L的废水处理的吸附率均大于97%, 均达到一级A出水的排放标准(≤1.53 mg/L, 以PO₄^3-计).     

Amino-Functionalized Titanium Based Metal-Organic Framework for Photocatalytic Hydrogen Production

Photocatalytic hydrogen production using stable metal-organic frameworks (MOFs), especially the titanium-based MOFs (Ti-MOFs) as photocatalysts is one of the most promising solutions to solve the energy crisis. However, due to the high reactivity and harsh synthetic conditions, only a limited number of Ti-MOFs have been reported so far. Herein, we synthesized a new amino-functionalized Ti-MOFs, named NH₂-ZSTU-2 (ZSTU stands for Zhejiang Sci-Tech University), for photocatalytic hydrogen production under visible light irradiation. The NH₂-ZSTU-2 was synthesized by a facile solvothermal method, composed of 2,4,6-tri(4-carboxyphenylphenyl)-aniline (NH₂-BTB) triangular linker and infinite Ti-oxo chains. The structure and photoelectrochemical properties of NH₂-ZSTU-2 were fully studied by powder X-ray diffraction, scanning electron microscope, nitro sorption isotherms, solid-state diffuse reflectance absorption spectra, and Mott–Schottky measurements, etc., which conclude that NH₂-ZSTU-2 was favorable for photocatalytic hydrogen production. Benefitting from those structural features, NH₂-ZSTU-2 showed steady hydrogen production rate under visible light irradiation with average photocatalytic H₂ yields of 431.45 μmol·g⁻¹·h⁻¹ with triethanolamine and Pt as sacrificial agent and cocatalyst, respectively, which is almost 2.5 times higher than that of its counterpart ZSTU-2. The stability and proposed photocatalysis mechanism were also discussed. This work paves the way to design Ti-MOFs for photocatalysis.     

Fluorescence Spectrometric Studies on the Binding of an Amino-Functionalized Ionic Liquid to Cytochrome c

The interaction of an amino-functionalized ionic liquid, 1-(2-aminoethyl)-3-butylimidazolium bromide ([NH₂C₂C₄im]Br), with cytochrome c (cyt c) at pH 7.4 was investigated using fluorescence and UV-Vis absorption spectroscopic techniques. From the experimental results, it is found that cyt c has a strong ability to quench the intrinsic fluorescence of [NH₂C₂C₄im]Br and the quenching mechanism is considered as a static quenching process. The binding constants and the number of binding sites (n) were calculated at different temperatures. The thermodynamic parameters such as free energy change (ΔG), enthalpy change (ΔH), and entropy change (ΔS) were calculated by thermodynamic equations. According to the results, the values of ΔG, ΔH, and ΔS are all negative, suggesting that interaction between [NH₂C₂C₄im]Br and cyt c is spontaneous and mainly driven by hydrogen bonding and van der Waals forces.     

Cavitation based cleaner technologies for biodiesel production and processing of hydrocarbon streams: A perspective on key fundamentals,missing process data and economic feasibility – A review

The present review emphasizes the role of hydrodynamic cavitation (HC) and acoustic cavitation in clean and green technologies for selected fuels (of hydrocarbon origins such as gasoline, naphtha, diesel, heavy oil, and crude oil) processing applications including biodiesel production. Herein, the role of cavitation reactors, their geometrical parameters, physicochemical properties of liquid media, liquid oxidants, catalyst loading, reactive oxygen species, and different types of emulsification and formation of radicals, formation as well as extraction of formed by-products are systematically reviewed. Among all types of HC reactors, vortex diode and single hole orifices revealed more than 95 % desulfurization yield and a 20 % viscosity reduction in heavy oil upgrading, while multi-hole orifice (100 holes) and slit Venturi allowed obtaining the best biodiesel production processes in terms of high (%) yield, low cost of treatment, and short processing time (5 min; 99 % biodiesel; 4.80 USD/m³). On the other hand, the acoustic cavitation devices are likely to be the most effective in biodiesel production based on ultrasonic bath (90 min; 95 %; 6.7 $/m³) and desulfurization treatment based on ultrasonic transducers (15 min; 98.3 % desulfurization; 10.8 $/m³). The implementation of HC-based processes reveals to be the most cost-effective method over acoustic cavitation-based devices. Finally, by reviewing the ongoing applications and development works, the limitations and challenges for further research are addressed emphasizing the cleaner production and guidelines for future scientists to assure obtaining comprehensive data useful for the research community.     

New strategies for synthesis of amino-functionalized poly(propylene carbonate) over SalenCo(III)Cl catalyst

New strategies for synthesis of amino-functionalized poly(propylene carbonate) (PPC) were applied by terpolymerization of carbon dioxide, propylene oxide, with (a) N-(2,3-epoxypropyl)-2-phthalimide (Monomer A )/N-(2-oxiranylmethyl)-1 or (b) N-(2-oxiranylmethyl)-1,1-dimethylethyl ester (Monomer B ) over SalenCo^(III)Cl/PPNCl catalysts system, followed by the removal of the respective protecting groups. The SalenCo^(III)Cl presented high activity and yielded the terpolymer with high polycarbonate selectivity, carbonate linkage content, as well as high head-to-tail stereoregularity (>99%). In terpolymerization, the Monomer A contents in PPC-Pht were easily regulated up to 12.0 mol%. However, the protecting groups could not be completely removed because of the degradation of PPC-NH₂- A during the deprotection process. Meanwhile, when terpolymerization with Monomer B , PPC-butoxy carbonyl was obtained varied the Monomer B contents from 1.3 to 4.5 mol%, and could be transformed completely into the amino-functionalized PPC-NH₂- B without significant backbone degradation. The contact angles of the functionalized PPC-NH₂s prepared by two strategies showed the expected increase in hydrophilicity with the increasing content of amino entities.     

Mesoporous Silica Nanoparticles Functionalized with Amino Groups for Biomedical Applications

The synthesis and characterization of amino-functionalized mesoporous silica nanoparticles are presented following two different synthetic methods: co-condensation and post-synthesis grafting of 3-aminopropyltriethoxysilane. The amino groups’ distribution on the mesoporous silica nanoparticles was evaluated considering the aggregation state of a grafted photosensitizer (Verteporfin) by using spectroscopic techniques. The homogeneous distribution of amino groups within the silica network is a key factor to avoid aggregation during further organic functionalization and to optimize the performance of functionalized silica nanoparticles in biomedical applications. In addition, the formation of a protein corona on the external surface of both bare and amino-functionalized mesoporous silica was also investigated by adsorbing Bovine Serum Albumin (BSA) as a model protein. The adsorption of BSA was found to be favorable, reducing the aggregation phenomena for both bare and amino-modified nanoparticles. Nevertheless, the dispersant effect of BSA was much more evident in the case of amino-modified nanoparticles, which reached monodispersion after adsorption of the protein, thus suggesting that amino-modified nanoparticles can benefit from protein corona formation for preventing severe aggregation in biological media.     

孔内富氨基的高稳定性铟基金属有机骨架高灵敏电化学传感多巴胺

为设计高稳定性且高灵敏度的纯金属有机骨架(MOF)电化学传感器以检测多巴胺(DA),我们选用铟基 MOF [In(2-NH₃-BDC)(2-NH₂-BDC)]·1.5H₂O(RSMOF-1,RSMOF=resistance switchable metal-organic framework,2-NH₂-H₂BDC=2-氨基对苯二甲酸)修饰玻碳电极(RSMOF-1/GCE)。制备的电极RSMOF-1/GCE的DPV测试结果显示其线性范围为0.990~663 μmol·L^-1、检出限为0.770 μmol·L^-1。在多种干扰物质如尿酸、尿素、葡萄糖和对乙酰氨基酚存在的条件下,RSMOF-1/GCE对 DA仍具有高的选择性。理论模拟结果显示,在RSMOF-1孔道内壁的—NH₂可通过氢键增强与DA分子的相互作用,使RSMOF-1/GCE具有灵敏的电化学传感DA的性能。