Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences
Not a member yet
3266 research outputs found
Sort by
A sensitive acetylcholinesterase biosensor based on gold nanorods modified electrode for detection of organophosphate pesticide
No full textA sensitive amperometric acetylcholinesterase (AChE) biosensor, based on gold nanorods (AuNRs), was developed for the detection of organophosphate pesticide. Compared with Au@Ag heterogeneous NRs, AuNRs exhibited excellent electrocatalytic properties, which can electrocatalytically oxidize thiocholine, the hydrolysate of acetylthiocholine chloride (ATCI) by AChE at +0.55 V (vs. SCE). The AChE/AuNRs/GCE biosensor was fabricated on basis of the inhibition of AChE activity by organophosphate pesticide. The biosensor could detect paraoxon in the linear range from 1 nM to 5 mu M and dimethoate in the linear range from 5 nM to 1 mu M, respectively. The detection limits of paraoxon and dimethoate were 0.7 nM and 3.9 nM, which were lower than the reported AChE biosensor. The proposed biosensor could restore to over 95% of its original current, which demonstrated the good reactivation. Moreover, the biosensor can be applicable to real water sample measurement. Thus, the biosensor exhibited low applied potential, high sensitivity and good stability, providing a promising tool for analysis of pesticides. (C) 2016 Elsevier B.V. All rights reserved
Prediction of low-rank coal pyrolysis behavior by chemical percolation devolatilization model
No full textThe chemical percolation devolatilization (CPD) model was proposed to predict the pyrolysis behavior of fast-heated coal based on the chemical structure of low-rank coal sample. The coal-dependent chemical structure parameters were taken directly from solid state C-13 nuclear magnetic resonance (NMR) analysis, with the exception of one empirical coefficient initial fraction of char bridges (c(0)). The Fourier transform infrared spectroscopic analysis was also employed to describe the pyrolysis characteristics of parent coal. The predictions of amount and characteristics of volatiles, tar and char from CPD model indicated that the crosslinking mechanism plays an important role for the pyrolysis of low-rank coal. In order to deeply understand the structure and chemical bonds of coal sample, the average chemical structure of low-rank coal was built by ACD/Labs software of ChemSketch. The C-13 NMR spectrum of established average coal structure fitted well with that of parent coal sample. (c) 2016 American Institute of Chemical Engineers Environ Prog, 35: 1215-1220, 201
Facile and sensitive electrochemical detection of methyl parathion based on a sensing platform constructed by the direct growth of carbon nanotubes on carbon paper
No full textThis work developed an economic, convenient, sensitive and practical methyl parathion sensor using an easy-to-fabricate, reusable, inexpensive carbon nanotube/carbon paper composite as the working electrode. Carbon nanotubes form a network structure and provide large surface area, which can enhance the electron transfer capability of the carbon paper electrode. As an electrochemical sensing platform, the constructed carbon nanotube/carbon paper sensor allows sensitive determination of methyl parathion in the range of 10 ng mL(-1) to 1000 ng mL(-1) with a low detection limit of 3.9 ng mL(-1). Importantly, the present study demonstrated the high sensitivity, satisfactory stability and good anti-interference capabilities of this new electrode platform for methyl parathion detection. Furthermore, the present method was successfully applied to determine methyl parathion in kiwi samples with satisfactory precision (3.74-5.05%) of relative standard deviation (RSD) and acceptable recoveries (99.67-108%), which demonstrated the applicability of the carbon nanotube/carbon paper composite sensor. Such a facile approach for the detection of OPs may provide some guidance for designing nanomaterial-based sensors
Efficient production of propionic acid through high density culture with recycling cells of Propionibacterium acidipropionici
No full textThe aim of this study was to explore propionic acid production via high density culture of Propionibacterium acidipropionici and recycling of cells. Results showed that final cells of P. acidipropionici from high density culture still had high metabolic activity for reuse. Using our process, 75.9 g l(-1) propionic acid was produced, which was 1.84-fold of that in fed-batch fermentation with low cell density (41.2 g l(-1)); the corresponding productivity was 100.0% higher than that in fed-batch fermentation with low cell density (0.16 g l(-1) h(-1)). This bioprocess may have potential for the industrial production of propionic acid. (C) 2016 Elsevier Ltd. All rights reserved
Electrospun melamine resin-based multifunctional nonwoven membrane for lithium ion batteries at the elevated temperatures
No full textA flame retardant and thermally dimensional stable membrane with high permeability and electrolyte wettability can overcome the safety issues of lithium ion batteries (LIBs) at elevated temperatures. In this work, a multifunctional thermoset nonwoven membrane composed of melamine formaldehyde resin (MFR) nano-fibers was prepared by a electro-spinning method. The resultant porous nonwoven membrane possesses superior permeability, electrolyte wettability and thermally dimensional stability. Using the electrospun MFR membrane, the LiFePO4/Li battery exhibits high safety and stable cycling performance at the elevated temperature of 120 degrees C. Most importantly, the MFR membrane contains lone pair electron in the nitrogen element, which can chelate with Mn2+ ions and suppress their transfer across the separator. Therefore, the LiMn2O4/graphite cells with the electrospun MFR multifunctional membranes reveal an improved cycle performance even at high temperature. This work demonstrated that electrospun MFR is a promising candidate material for high-safety separator of LIBs with stable cycling performance at elevated temperatures. (C) 2016 Elsevier B.V. All rights reserved
Electro-flotation of Chlorella sp assisted with flocculation by chitosan
No full textHarvest of algal biomass from dilute culture medium at low cost remains a major hurdle to industrial scale processing. Conventional harvesting methods are not only costly, but also affect any later downstream processes partly because of the metal ions contamination by flocculants. This work constructed an electro-flotation technique including two steps of flocculation by chitosan first and then sequential bubbling flotation by non-sacrificial graphite electrodes. Laboratory work has been carried out to investigate the influences of chitosan dosage, pH value, cell density of algal culture, stirring rate and mixing time on flocculation efficiency, and the voltage and current intensity imposed on electrodes and the space between electrodes on flotation efficiency. Moreover, a 1000 L pilot bench of electro-flotator constructed to harvest Chlorella sp. was tested. Around 90% of total recovery efficiency and 50 times concentration rate have been reached, and only 23.7 g chitosan and 0.43 kWh of electricity are required to harvest 1 kg biomass. Above results proved electro-flotation by graphite electrodes assisted with chitosan is a safe and cost effective approach for microalgae harvesting. (C) 2016 Elsevier B.V. All rights reserved
Siliceous tin phosphates as effective bifunctional catalysts for selective conversion of dihydroxyacetone to lactic acid
No full textMethods to catalytically convert carbohydrates into lactic acid (LA), which is a versatile platform chemical, have been widely investigated. In this study, siliceous tin phosphates were utilized as reusable Bronsted-Lewis acid bifunctional catalysts during the conversion of 1,3-dihydroxyacetone (DHA) to LA under hydrothermal conditions. The product distribution closely depended on the reaction temperature, catalyst loading and substrate concentration. The highest LA yield of 93.8% was achieved with a complete DHA conversion at 140 degrees C after 5 h. The reaction was facilitated by the vast presence of Bronsted and Lewis acid sites that were confirmed by both pyridine FTIR and NH3-TPD analysis. The incorporation of silica significantly lowered the Sn content and improved the thermal stability of the tin phosphate catalysts. A possible reaction mechanism was proposed in that the Lewis and Bronsted acid sites synergistically catalyzed the conversion of pyruvaldehyde to LA, which was found to be the rate-determining step. The method allows for facile catalyst separation and recycling while expanding the applicability of silica in the field of biomass-to-chemical conversion
Novel cellulose/polyurethane composite gel polymer electrolyte for high performance lithium batteries
No full textThe increasing interest in gel polymer electrolyte for the lithium battery is attributed to its excellent plasticity, enhanced safety and significantly improved electrochemical stability. Herein, on account of the two-phase structure of thermoplastic polyurethane (TPU) consisting of soft and hard segments, the cellulose/TPU with ether bond composite gel polymer electrolyte (CGPE) was fabricated and investigated for applications in lithium batteries. This study demonstrated that the CGPE possessed preeminent comprehensive properties such as sufficient ionic conductivity (4.8 x 10(-4) S cm(-1)) at 80 degrees C, high lithium ion transport number (t(+) = 0.68) and improved electrochemical stability. Moreover, the assembled LiFePO4/Li battery using CGPE exhibitedoutstanding rate capacity and remarkable cycle performance at the elevated temperature of 80 degrees C. Notably, the discharge capacity was still 128.2 mAh g(-1) after 200 cycles, 95% of the capacity retention at a charge/discharge rate of 2C. These findings suggest that CGPE is a very prospective polymer electrolyte for high-performance lithium batteries. (C) 2016 Elsevier Ltd. All rights reserved
