Alternative solvent‐based methyl benzoate vortex‐assisted dispersive liquid–liquid microextraction for the high‐performance liquid chromatographic determination of benzimidazole fungicides in environmental water samples

Vortex‐assisted dispersive liquid–liquid microextraction using methyl benzoate as an alternative extraction solvent for extracting and preconcentrating three benzimidazole fungicides (i.e., carbendazim, thiabendazole, and fluberidazole) in environmental water samples before high‐performance liquid chromatographic analysis has been developed. The selected microextraction conditions were 250 μL of methyl benzoate containing 300 μL of ethanol, 1.0% w/v sodium acetate, and vortex agitation speed of 2100 rpm for 30 s. Under optimum conditions, preconcentration factors were 14.5–39.0 for the target fungicides. Limits of detection were obtained in the range of 0.01–0.05 μg/L. The proposed method was then applied to surface water samples and the recovery evaluations at three spiked concentration levels of 5, 30, and 50 μg/L were obtained in the range of 77.4–110.9% with the relative standard deviation <7.4%. The present method was simple, rapid, low cost, sensitive, environmentally friendly, and suitable for the trace analysis of the studied fungicides in environmental water samples.     

Removal of Anionic Dyes from Aqueous Solution with Layered Cationic Aluminum Oxyhydroxide

It is highly desired yet challenged to find an adsorbent with low cost and excellent performance in the removal of organic dyes from aqueous solution. Here we reported that a layered cationic aluminum oxyhydroxide material hydrothermally synthesized from the low-cost source materials of AlCl₃∙6H₂O, CaO and H₂O, known as JU-111, can meet such criterion in removing methyl orange(MO) and Congo red(CR). JU-111 shows fast adsorption kinetics[especially for CR(15 s)] and high adsorption capacity(MO:>1000 mg/g; CR:>2900 mg/g), surpassing most of the reported adsorbents. Comprehensive characterizations of the adsorption process of MO and CR revealed that both adsorptions were achieved via the anion exchange process. The characteristics of extremely low cost and excellent performance render JU-111 great potential in the practical applications in the removal of anionic dyes.     

Development of highly ionic conductive cellulose acetate-g-poly (2-acrylamido-2-methylpropane sulfonic acid-co-methyl methacrylate) graft copolymer membranes

A novel cellulose acetate-g-poly (2-acrylamido-2-methylpropane sulfonic acid-co- methyl methacrylate) copolymer was prepared via free radical polymerization for the first time. The chemical structure of the graft copolymer was confirmed using FT-IR, ¹H NMR and EDX. The TGA and DSC investigated the thermal changes. Factors affecting the grafting process were studied and various grafting characteristic parameters such as grafting efficiency (%), grafting yield (%) and add-on value (%) were determined. Flexible membranes based on different graft copolymer compositions were fabricated by simple solution casting. Physicochemical properties including ion exchange capability (IEC), water uptake (WU) and proton conductivity (σ) were evaluated. These membranes demonstrated higher IEC, WU and conductivity than the pristine CA. The maximum proton conductivity of the CA-g-poly (2-acrylamido-2-methylpropane sulfonic acid-co- methyl methacrylate) copolymer membrane (68%; Add-on %) was found to be 6.44 × 10⁻³ S/cm compared with 0.035 × 10⁻³ S/cm of the pristine CA. Thus, the appropriate graft copolymer composition will allow fine-tuning of the physical characteristics and led to several potential applications, such as polyelectrolyte fuel cells membranes or biodiesel production.     

Efficient Synthesis of p-Hydroxyphenyl Ethanol from Hydrogenation of Methyl p-Hydroxyphenylacetate with CNTs-promoted Cu-Zr Catalyst

Hydrogenation of methyl p-hydroxyphenylacetate has been used for the synthesis of p-hydroxyphenyl ethanol. The reaction was catalyzed by Cu_iZr_j-x%(mass fraction) carbon nanotubes(CNTs) catalysts. Incorporation of a minor amount of CNTs into Cu_iZr_j oxide can visibly increase the catalytic activity for the synthesis of p-hydroxyphenyl ethanol. The yield of p-hydroxyphenyl ethanol reaches 94.2% over a co-precipitated catalyst of Cu₃Zr₁ oxide with 11.0%CNTs. Its catalytic activity shows no obvious decrease after three cycles. This is much better than the CNT-free co-precipitated catalyst with a good yield of 81.1%, Cu₃Zr₁-0%CNTs.     

Development of Biosensor for Catechol Using Electrosynthesized Poly(3‐methylthiophene) and Incorporation of LAC Simultaneously

Simultaneous electropolymerization of 3‐methylthiophene and incorporation of Laccase (LAC) was carried out in the presence of propylene carbonate as a medium by amperometric method. This enzyme modified electrode was used for the sensing of polyphenol. Catechol is taken as a model compound for the study. UV‐Vis spectral studies suggest no denaturation of LAC in presence of propylene carbonate. The SEM studies reveal the surface morphology and incorporation of LAC in P3MT with agglomerated flaky masses are observed in with and without enzyme micrographs. The cyclic voltammograms were recorded for 0.01 mM catechol on plain glassy carbon, polymer and enzyme incorporated electrodes at pH 6.0 and scan rate 50 mV s^?1. The fabricated electrochemical biosensor was used for the determination of catechol in aqueous solution by Differential Pulse Voltammetry (DPV) technique. The concentration linear range of 8×10^?8 to 1.4×10^?5 M a value of Michealis? Menten constant K_m=7.67 µmol dm^?3 and activation energy is 32.75 kJ mol^?1. It retains 83 % of the original activity after 60 days which is much higher than that of other biosensors. The developed biosensor was used to quantify catechol in the determination in real samples.     

可见光响应的CO3(PO4)2/Ag3PO4纳米复合光催化剂的制备及表征

采用简单的化学偏聚法合成出Ag3PO4纳米颗粒、磷酸钴(Co3(PO4)2,CoP)纳米片以及它们两者的纳米复合结构(CoP/Ag3PO4),同时还比较了它们的可见光催化活性.采用场发射扫描电镜(FESEM)、X射线衍射(XRD)、紫外-可见(UV-Vis)吸收光谱以及光致发光谱等手段对其形貌、结构、光学以及可见光催化性能等进行表征.结果表明,CoP/Ag3PO4复合纳米结构的可见光降解甲基橙(MO)的速率和循环稳定性均明显优于其它两种物质.这表明CoP应该起着共催化剂的作用,它能够抑制光生电子与空穴之间的复合,并且提供大量高活性的光生空穴.此外,我们还发现CoP/Ag3PO4降解另一种阳离子型染料——罗丹明B(RhB)的能力则远不如纯Ag3PO4,这可能是与光催化剂的表面性质发生改变有关,造成更低的RhB吸附能力.本文提供了一种廉价制备高效可见光催化剂的新方法.     

无碱条件下Au/ZnO选择性催化氧化1,3-丙二醇合成3-羟基丙酸甲酯

采用溶胶-沉积法合成了高选择性的Au/ZnO催化剂,用于1,3-丙二醇选择性氧化酯化为3-羟基丙酸甲酯的反应.研究了保护剂PVA用量、金溶胶合成温度、金负载量及催化剂循环利用对反应的影响,且优化了反应温度和反应压力,并对催化剂进行了XRD和TEM表征.结果表明,PVA∶Au(m/m)=1∶4、金溶胶合成温度25℃、金负载量1%的Au/ZnO对目标反应的催化活性最好,在100℃和Po2=2MPa的条件下1,3-丙二醇的转化率达82.8%,产物3-羟基丙酸甲酯的选择性达95.4%.Au纳米粒子的粒径影响催化性能,在Au平均粒径为2.8~6.1nm的范围内,产物选择性随Au纳米粒子的粒径的减小而增大,平均粒径在2.8~4.8nm的范围内时,催化剂具有较好的产物选择性(大于90%);Au/ZnO催化剂循环利用4次后催化性能(转化率和选择性)无明显下降;并推测了无碱条件下Au/ZnO选择性催化氧化1,3-丙二醇合成3-羟基丙酸甲酯的反应机制.     

热扩散法制备MoO3/SiO2催化草酸二甲酯和苯酚酯交换反应

采用热扩散法（TS）和等体积浸渍法制备了MoO₃/SiO₂催化剂用于草酸二甲酯和苯酚酯交换反应.结果表明,热扩散法制备的10%MoO₃/SiO₂-TS催化剂较等体积浸渍法制备的10%MoO₃/SiO₂-C催化剂具有更好的催化性能.运用X射线衍射、Raman光谱、X射线光电子能谱分析、吡啶吸附红外光谱、NH₃程序升温脱附等手段对催化剂进行了表征,发现虽然两种方法制备的催化剂都只有弱Lewis酸中心,钼均以氧化钼单体形式存在,未形成解离和聚合,但是10%MoO₃/SiO₂-TS催化剂较10%MoO₃/SiO₂-C催化剂表面钼含量更高且MoO₃分散得更好.在苯酚用量为0.2mol,10%MoO₃/SiO₂-TS催化剂用量为1.2g,反应温度为180℃,草酸二甲酯与苯酚的摩尔比为2,反应时间为4h的优化条件下,苯酚转化率可达70.9%,甲基苯基草酸酯和草酸二苯酯的收率分别达63.1%和7.7%.     

可见光驱动Ag3PO4催化降解罗丹明B和甲基橙

采用简易离子交换法制备可见光驱动Ag3PO4光催化剂.通过X射线衍射、场发射扫描电子显微镜、N2吸附-脱附、紫外-可见漫反射光谱及傅里叶变换红外光谱对所制备的Ag3PO4催化剂进行表征.结果表明,在可见光照射下,Ag3PO4催化剂对罗丹明B降解表现出优越的光催化活性,但对甲基橙的降解活性低,这归因于Ag3PO4催化剂对甲基橙分子吸附量低.可见光照Ag3PO4反应体系中,空穴和超氧自由基共同发挥作用导致罗丹明B和甲基橙光催化降解.在罗丹明B的协助作用下,Ag3PO4催化剂对甲基橙的可见光催化降解活性大大增强,这是由于罗丹明B的存在可产生更多的超氧自由基,从而使甲基橙进一步降解.