Zou Bin

Alkaline Ionic Liquid Modified Pd/C Catalyst as an Efficient Catalyst for Oxidation of 5-Hydroxymethylfurfural

Conversion of HMF into FDCA was carried out by a simple and green process based on alkaline ionic liquid (IL) modified Pd/C catalyst (Pd/C-OH−). Alkaline ionic liquids were chosen to optimize Pd/C catalyst for special hydrophilicity and hydrophobicity, redox stability, and unique dissolving abilities for polar compounds. The Pd/C-OH− catalyst was successfully prepared and characterized by SEM, XRD, TG, FT-IR, and CO2-TPD technologies. Loading of alkaline ionic liquid on the surface of Pd/C was 2.54u2009mmol·g−1. The catalyst showed excellent catalytic activity in the HMF oxidation after optimization of reaction temperature, reaction time, catalyst amount, and solvent. Supported alkaline ionic liquid (IL) could be a substitute and promotion for homogeneous base (NaOH). Under optimal reaction conditions, high HMF conversion of 100% and FDCA yield of 82.39% were achieved over Pd/C-OH− catalyst in water at 373u2009K for 24u2009h.

Quick separation and enzymatic performance improvement of lipase by ionic liquid-modified Fe 3 O 4 carrier immobilization

To promote the activity and stability of immobilized porcine pancreatic lipase (PPL), novel carrier was combined with special immobilization method. Enzymatic activity was enhanced after immobilized onto ionic liquid modified magnetic Fe3O4 by electrostatic adsorption. Activity of immobilized enzyme (PPL-IM/BF4-Fe3O4@CA) reached 596xa0U/g PPL. Through the combination of electrostatic adsorption and embedding immobilization methods, we improve binding force between the carrier and enzyme, and further enhance the efficiency and stability of immobilized enzyme. The activity of PPL-IM/BF4-Fe3O4@CA after repeated third use was 78%. After storage at room temperature for 5xa0days, the residual activity was 89%. Enzymatic properties and catalytic kinetics of immobilized enzymes were studied, and the effect mechanism of ionic liquid modified Fe3O4 on PPL was revealed. The effect of ionic liquid on the carrier structure was investigated by characterization of XRD, FT-IR, SEM and TG. The mechanism and enzymatic properties of immobilized PPL via electrostatic adsorption and embedding were analyzed. A novel and efficient immobilized PPL was developed.

Acetylcholinesterase biosensor based on functionalized surface of carbon nanotubes for monocrotophos detection

Monocrotophos (Ops) has been widely used as pesticide in crop production but simultaneously could accumulate in the nature and seriously impact food safety and human health. It is necessary to develop a high sensitivity biosensor for accurate and fast detection of OPs. In this study, multi-walled carbon nanotubes (MWCNTs) were selected as acetylcholinesterase (AChE) carrier and their surface was modified by introducing different functional groups (-SH, -NH2, -Cl, -OH), hydrophobic alkyl groups (-CH3, -(CH2)2CH3, -(CH2)7CH3, -(CH2)15CH3) and ionic liquids (-IL1, -IL2). The interaction mechanism of MWCNTs functionalized surface and AChE has been revealed by studying characteristics of AChE immobilized on different carrier surface. Finally, compared with reported references and above other modifiers, we found that MWCNTs surface modified by -IL1 was the best carrier for AChE and the detection limit of IL1-MWCNTs/AChE/GCE was 3.3u202f×u202f10-11u202fM. At optimum reaction condition (pH 7.0, AChE loading 0.25 U, Inhibition time 14u202fmin), storability test indicated reactivity of IL1-MWCNTs/AChE/GCE remained above 98.5% within two weeks. For real vegetable sample detection, the recoveries of IL1-MWCNTs/AChE/GCE were found to be between 90.0% and 104%. These results demonstrated novel biosensors could act as device of high sensitivity for accurate and fast detection of OPs.