Rational structural design of ZnOHF nanotube-assembled microsphere adsorbents for high-efficient Pb2+ removal

CrystEngComm ◽  
2020 ◽  
Vol 22 (44) ◽  
pp. 7543-7548
Author(s):  
Yingying Guo ◽  
Nan Liu ◽  
Tongming Sun ◽  
Huihui Cui ◽  
Jin Wang ◽  
...  

Hierarchical nanotube-assembled ZnOHF microspheres were prepared via an amino acid assisted hydrothermal method, which can remove Pb2+ efficiently in an aqueous environment.

2011 ◽  
Vol 47 (2) ◽  
pp. 193-201
Author(s):  
N. E. Borisova ◽  
F. E. Zhurkin ◽  
T. G. Gulevich ◽  
K. K. Babievskii ◽  
M. D. Reshetova ◽  
...  

2014 ◽  
Vol 14 (3) ◽  
pp. 497-504
Author(s):  
Carlo Canepa

AbstractThis work investigates the consequences on the diverse number of chemical species in a pre-biotic terrestrial aqueous environment endowed with an amino acid source induced by the spontaneous build-up of catalytically active polypeptides from amino acid monomers. The assumed probability that a randomly formed polypeptide exhibits catalytic properties is dependent on constraining both the chemical identity and the position of a fraction of the amino acid residues. Within this hypothesis, and using values of the average length n of the catalytic polypeptides about one half of the present-day enzymes, the stationary-state concentration of the catalytically active polypeptides is ≈10−30 −10−19 M, and the ratio of the concentration of a product of a catalytic process to the initial concentration of the corresponding substrate is predicted to be ≈10−6−105. Matching the mean life of each catalytic polypeptide to the mean life of its substrate (λ ≈ ω) is only possible by significantly raising the intensity of the source of the amino acid monomers. Under these hypothetical optimal conditions, the mean lives of the catalytic polypeptides and their substrates have values ω−1 ≈ λ−1 ≈10 yr and the asymptotic concentration of each product is of the same order of magnitude as the concentration of the substrate. In all cases the catalytic efficiency necessary to form the active peptides takes the typical values of present-day enzymes.


2020 ◽  
Vol 22 (19) ◽  
pp. 6357-6371 ◽  
Author(s):  
Kai Chen ◽  
Xueqing Qiu ◽  
Dongjie Yang ◽  
Yong Qian

Biocompatible amino acid-modified lignin polyampholytes exhibit outstanding antibacterial activity and bio-adhesion resistance, which are successfully demonstrated in personal protection masks.


2021 ◽  
Author(s):  
Minxue Liu ◽  
Fengli Yu ◽  
Bing Yuan ◽  
Congxia Xie ◽  
Shitao Yu

Abstract Background: Propionic acid as a very valuable chemical is in high demand, and it is industrially produced via the oxo-synthesis of ethylene or ethyl alcohol and via the oxidation of propionaldehyde with oxygen. It is urgent to discover a new preparation method for propionic acid via a green route. Recyclable amino-acid-based organic-inorganic heteropolyoxometalates were first used to high-efficiently catalyse the selective oxidation of n-propanol to propionic acid with H2O2 as an oxidant.Result: A series of amino-acid-based heteropoly catalysts using different types of amino acids and heteropoly acids were synthesized, and the experimental results showed proline-based heteropolyphosphatotungstate [ProH]3PW12O40 exhibited excellent catalytic activity for the selective catalytic oxidation of n-propanol to propionic acid owing to its high capacity as an oxygen transfer agent and suitable acidity. Under optimized reaction conditions, the conversion of n-propanol and the selectivity of propionic acid reached 88% and 75%, respectively. Over four cycles, the conversion remained at ˃80%, and the selectivity was ˃60%. [ProH]3PW12O40 was also used to catalyse the oxidations of n-butanol, n-pentanol, n-hexanol, and benzyl alcohol. All the reactions had high conversions, with the corresponding acids being the primary oxidation product.Conclusions: Proline-based heteropolyoxometalate [ProH]3PW12O40 has been successfully used to catalyse the selective oxidation of primary alcohols to the corresponding carboxylic acids with H2O2 as the oxidant. The new developed catalytic oxidation system is mild, high-efficient, and reliable. This study provides a potential green route for the preparation propionic acid.


2017 ◽  
Author(s):  
Wei Tian ◽  
Hammad Naveed ◽  
Meishan Lin ◽  
Jie Liang

AbstractFree energy of transferring amino acid side–chains from aqueous environment into lipid bilayers, known as transfer free energy (TFE), provides important information on the thermodynamic stability of membrane proteins. In this study, we derived a TFE profile named General Transfer Free Energy Profile (GeTFEP) based on computation of the TFEs of 58 β–barrel membrane proteins (βMPs). The GeTFEP agrees well with experimentally measured and computationally derived TFEs. Analysis based on the GeTFEP shows that residues in different regions of the TM segments of βMPs have different roles during the membrane insertion process. Results further reveal the importance of the sequence pattern of transmembrane strands in stabilizing βMPs in the membrane environment. In addition, we show that GeTFEP can be used to predict the positioning and the orientation of βMPs in the membrane. We also show that GeTFEP can be used to identify structurally or functionally important amino acid residue sites of βMPs. Furthermore, the TM segments of α–helical membrane proteins can be accurately predicted with GeTFEP, suggesting that the GeTFEP captures fundamental thermodynamic properties of amino acid residues inside membrane, and is of general applicability in studying membrane protein.


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