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Nan Zhou, Honggang Chen, Junting Xi, Denghui Yao, Zhi Zhou, Yun Tian, Xiangyang Lu
Fresh and dehydrated banana peels were used as biomass feedstock to produce highly effective sorbent biochars through a facile one-step hydrothermal carbonization approach with 20%vol phosphoric acid as the reaction medium. The elemental ratio of oxygen content of the two as-prepared biochars were about 20%, and the FT-IR analysis confirmed the existence of abundant surface functional groups such as hydroxyl and carboxyl which greatly enhanced the adsorption performance. The sorbents showed excellent lead clarification capability of 359mg·g(-1) and 193mg·g(-1) for dehydrated and fresh banana peels based biochars, respectively...
February 12, 2017: Bioresource Technology
Miriam Kellock, Jenni Rahikainen, Kaisa Marjamaa, Kristiina Kruus
Non-productive enzyme binding onto lignin is the major inhibitory mechanism, which reduces hydrolysis rates and yields and prevents efficient enzyme recycling in the hydrolysis of lignocellulosics. The detailed mechanisms of binding are still poorly understood. Enzyme-lignin interactions were investigated by comparing the structural properties and binding behaviour of fungal monocomponent enzymes, cellobiohydrolases TrCel7A and TrCel6A, endoglucanases TrCel7B and TrCel5A, a xylanase TrXyn11 and a β-glucosidase AnCel3A, onto lignins isolated from steam pretreated spruce and wheat straw...
February 11, 2017: Bioresource Technology
Yuya Hirano, Yasuhiko Iwasaki
Chemotherapy is the most reliable treatment for osteoporosis and osseous metastases. To facilitate better drug delivery for bone treatments, a novel preparation of polymeric nanoparticles with high affinity to bone has been prepared. Two-step synthesis of cholesteryl-functionalized poly(ethylene sodium phosphate) (Ch-PEPn·Na) was performed via ring-opening polymerization of cyclic phosphoesters and the demethylation. The molecular weight of Ch-PEPn·Na could be well controlled by changing the ratio of cholesterol and cyclic phosphoesters...
February 16, 2017: Colloids and Surfaces. B, Biointerfaces
Wupeng Gan, Yin Gu, Junping Han, Caixia Li, Jing Sun, Peng Liu
Plastic microfluidic devices with embedded chitosan-modified Fusion 5 filter paper (unmodified one purchased from GE Healthcare) have been successfully developed for DNA extraction and concentration, utilizing two different mechanisms for DNA capture: the physical entanglement of long-chain DNA molecules with the fiber matrix of the filter paper and the electrostatic adsorption of DNA to the chitosan-modified filter fibers. This new method not only provided a high DNA extraction efficiency at a pH of 5 by synergistically combining these two capture mechanisms together, but also resisted the elution of DNA from filters at a pH >8 due to the entanglement of DNA with fibers...
February 23, 2017: Analytical Chemistry
Erica Megumi Kataoka, Rui Cesar Murer, Jandyson Machado Santos, Rogerio Mesquita de Carvalho, Marcos Nogueira Eberlin, Fabio Augusto, Ronei Jesus Poppi, Angelo Luiz Gobbi, Leandro Wang Hantao
In this study, we introduce a simple protocol to manufacture disposable, 3D-printed microfluidic systems for sample preparation of petroleum. Such platform is produced with a consumer-grade 3D-printer, using fused deposition modeling. Successful incorporation of solid-phase extraction (SPE) to microchip was ensured by facile 3D element integration using proposed approach. This 3D-printed μSPE device was applied to challenging matrices in oil & gas industry, such as crude oil and oil-brine emulsions. Case studies investigated important limitations of non-silicon and non-glass microchips, namely, resistance to nonpolar solvents and conservation of sample integrity...
February 23, 2017: Analytical Chemistry
Moran Balaish, Yair Ein-Eli
Perfluorocrbons (PFCs) are considered advantageous additives to non-aqueous Li-O2 battery due to their superior oxygen solubility and diffusivity compared to common battery electrolytes. Up to now, the main focus was concentrated on PFCs-electrolyte investigation, however no special attention was granted to the role of carbon structure in the PFCs- Li-O2 system. Immiscible PFCs, rather than miscible fluorinated-ethers, were added to activated-carbon class air-electrode due to their higher susceptibility towards attack and to their ability to shift the reaction from two phase to an artificial three phase reaction zone...
February 23, 2017: ACS Applied Materials & Interfaces
Fernanda Grandzolli Santos, Leticia Caroline Bonkovoski, Francielle P Garcia, Thelma Sley Pacheco Cellet, Maria Alice Witt, Celso Vataru Nakamura, Adley Forti Rubira, Edvani Curti Muniz
In the present study, nanofiber meshes (NFs), composed of polycaprolactone and poly[(2-dimethylamino) ethyl methacrylate] at 80/20 and 50/50 PCL/PDMAEMA blend ratios, were obtained through electrospinning. Silver nanoparticles (AgNPs) formed in situ were then immobilized on NF surfaces through adsorption processes, at different pHs. It was possible to observe that the amount of NF-AgNPs can be tuned by changing the pH of AgNPs-immobilization and the PCL/PDMAEMA ratio in the blend. The neat NF and NF-AgNPs were characterized with respect to their morphology and mechanical properties...
February 23, 2017: ACS Applied Materials & Interfaces
Maria Ricci, William Trewby, Clodomiro Cafolla, Kislon Voïtchovsky
The dynamics of ions adsorbed at the surface of immersed charged solids plays a central role in countless natural and industrial processes such as crystal growth, heterogeneous catalysis, electrochemistry, or biological function. Electrokinetic measurements typically distinguish between a so-called Stern layer of ions and water molecules directly adsorbed on to the solid's surface, and a diffuse layer of ions further away from the surface. Dynamics within the Stern layer remain poorly understood, largely owing to a lack of in-situ atomic-level insights...
February 23, 2017: Scientific Reports
Oren Ben Dor, Shira Yochelis, Anna Radko, Kiran Vankayala, Eyal Capua, Amir Capua, See-Hun Yang, Lech Tomasz Baczewski, Stuart Stephen Papworth Parkin, Ron Naaman, Yossi Paltiel
Ferromagnets are commonly magnetized by either external magnetic fields or spin polarized currents. The manipulation of magnetization by spin-current occurs through the spin-transfer-torque effect, which is applied, for example, in modern magnetoresistive random access memory. However, the current density required for the spin-transfer torque is of the order of 1 × 10(6) A·cm(-2), or about 1 × 10(25) electrons s(-1) cm(-2). This relatively high current density significantly affects the devices' structure and performance...
February 23, 2017: Nature Communications
Sergey N Filimonov, Wei Liu, Alexandre Tkatchenko
The design of novel elementary surface processes is important for applications in catalysis, single-molecule junctions, molecular sensors, switches and surface mounted molecular machines. Here we demonstrate by van der Waals inclusive density functional theory calculations that a small and relatively simple heteroaromatic compound s-triazine (C$_3$H$_3$N$_3$) unexpectedly possesses five metastable states when adsorbed on the Pt(111) surface. This diversity of the adsorption states stems from an interplay between versatile molecule/surface chemical bonding and van der Waals interactions and from ``softening'' of the aromatic ring by nitrogen substitution, which makes folding of the aromatic ring energetically much less demanding as compared to benzene...
February 23, 2017: Journal of Physical Chemistry Letters
Hye In Yang, Kangyi Lou, Anushka Upamali Rajapaksha, Yong Sik Ok, Anthony O Anyia, Scott X Chang
Ammonium (NH4(+)) is a common form of reactive nitrogen in wastewater, and its discharge to water bodies can lead to eutrophication. This study was conducted to understand NH4(+) adsorption mechanisms of pine sawdust and wheat straw biochars in aqueous solutions and the factors affecting NH4(+) removal. Biochars were produced by pyrolysing pine sawdust at 300 °C (PS300) and 550 °C (PS550) and wheat straw at 550 °C (WS550). Pseudo-second-order and Redlich-Peterson models best fitted the adsorption data...
February 22, 2017: Environmental Science and Pollution Research International
Shuo Yao, Tong Xu, Nian Zhao, Lirong Zhang, Qisheng Huo, Yunling Liu
A novel metal-organic framework, [(CH3)2NH2]2[Cu3O(SO4)3Cu2L2(DMF)(H2O)]·9DMF (JLU-Liu39) H2L = pyridine-3,5-bis(phenyl-4-carboxylic acid), has been successfully synthesized under solvothermal conditions. Structure analysis indicates that the framework of JLU-Liu39 is constructed by ternary building units which include a rare hexa-nuclear [Cu6O2(SO4)6] cluster, a classical [Cu2(CO2)4] paddlewheel, and a 3-connected hetero-N, O donor ligand. The whole 3D framework possesses a (3,4,4)-connected fjh topology and a large window size of 25...
February 23, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Azar Farjamnia, Bret Jackson
A quantum approach based on an expansion in vibrationally adiabatic eigenstates is used to explore the dissociative chemisorption of CO2 on Ni(100). The largest barrier to reaction corresponds to the formation of a bent anionic molecular precursor, bound to the surface by about 0.24 eV. The barrier to dissociation from this state is small. Our computed dissociative sticking probabilities on Ni(100) for molecules in the ground state are in very good agreement with available experimental data, reasonably reproducing the variation in reactivity with collision energy...
February 21, 2017: Journal of Chemical Physics
Danilo Roccatano, Edita Sarukhanyan, Ronen Zangi
Peptides are versatile molecules with applications spanning from biotechnology to nanomedicine. They exhibit a good capability to unbundle carbon nanotubes (CNT) by improving their solubility in water. Furthermore, they are a powerful drug delivery system since they can easily be uptaken by living cells, and their high surface-to-volume ratio facilitates the adsorption of molecules of different natures. Therefore, understanding the interaction mechanism between peptides and CNT is important for designing novel therapeutical agents...
February 21, 2017: Journal of Chemical Physics
Eugene Strativnov
We propose the technology of obtaining the promising material with wide specter of application-activated nanostructured carbon. In terms of technical indicators, it will stand next to the materials produced by complex regulations with the use of costly chemical operations. It can be used for the following needs: as a sorbent for hemosorption and enterosorption, for creation of the newest source of electric current (lithium and zinc air batteries, supercapacitors), and for processes of short-cycle adsorption gas separation...
December 2017: Nanoscale Research Letters
Long Pan, Yuichi Takagi, Yoshihiko Matsui, Taku Matsushita, Nobutaka Shirasaki
We milled granular activated carbons (GACs) that had been used for 0-9 years in water treatment plants and produced carbon particles with different sizes and ages: powdered activated carbons (PAC, median diameter 12-42 μm), superfine PAC (SPAC, 0.9-3.5 μm), and submicron-sized SPAC (SSPAC, 220-290 nm). The fact that SPAC produced from 1-year-old GAC and SSPAC from 2-year-old GAC removed 2-methylisoborneol (MIB) from water with an efficiency similar to that of virgin PAC after a carbon contact time of 30 min suggests that spent GAC could be reused for water treatment after being milled...
February 14, 2017: Water Research
Jana Naceradska, Martin Pivokonsky, Lenka Pivokonska, Magdalena Baresova, Rita K Henderson, Arash Zamyadi, Vaclav Janda
The study investigates the effect of permanganate pre-oxidation on the coagulation of peptides/proteins of Microcystis aeruginosa which comprise a major proportion of the organic matter during cyanobacterial bloom decay. Four different permanganate dosages (0.1, 0.2, 0.4 and 0.6 mg KMnO4 mg(-1) DOC) were applied prior to coagulation by ferric sulphate. Moreover, changes in sample characteristics, such as UV254, DOC content and molecular weight distribution, after pre-oxidation were monitored. The results showed that permanganate pre-oxidation led to a reduction in coagulant dose, increased organic matter removals by coagulation (by 5-12% depending on permanganate dose), microcystin removal (with reductions of 91-96%) and a shift of the optimum pH range from 4...
February 14, 2017: Water Research
Sijie Zou, Yong Liao, Shangchao Xiong, Nan Huang, Yang Geng, Shijian Yang
The non-recyclability of the sorbents used to capture Hg0 from the flue gas causes a high operation cost and the potential risk of exposure to Hg. The installment of wet electrostatic precipitators (WESPs) in coal-fired plants makes the recovery of spent sorbents for recycling and the centralized control of Hg pollution possible. In this work, H2S-modified Fe-Ti spinel was developed as a recyclable magnetic sorbent to recover Hg0 from the flue gas as a co-benefit of the WESP. Although Fe-Ti spinel exhibited poor Hg0 capture activity in the temperature range of the flue gas downstream of the flue gas desulfurization (FGD), H2S-modified Fe-Ti spinel exhibited excellent Hg0 capture performance with an average adsorption rate of 1...
February 22, 2017: Environmental Science & Technology
Ruming Yuan, Baohuan Wei, Gang Fu
Density functional theory calculations have been carried out to explore the detailed mechanisms for carbon dioxide incorporation of N-unsubstituted propargylic amine catalyzed by Ag(I) catalysts. We show that the reaction undergoes substrate adsorption or displacement, isomerization from amine-coordinated species to the alkyne-coordinated species, CO2 attack and proton transfer, giving the carbamate intermediate. Subsequently, the reaction would bifurcate at the intermolecular ring closing step, which produces five-membered ring (5MR) and six-membered ring (6MR) products at the same time, thus raising a regioselectivity issue...
February 22, 2017: Journal of Organic Chemistry
Jinglei Chen, Guanyong Wang, Yanan Tang, Hao Tian, Jinpeng Xu, Xianqi Dai, Hu Xu, Jinfeng Jia, Wingkin Ho, Maohai Xie
Monolayer (ML) transition-metal dichalcogenides exist in different phases, such as hexagonal (2H) and monoclinic (1T') structures. They show very different properties: semiconducting for 2H-MoTe2 and semi-metallic for 1T'-MoTe2. The formation energy difference between 2H and 1T' phase MoTe2 is small, so there is a high chance to tune the structures of MoTe2 and thereby to bring in applications of phase-change electronics. In this paper, we report growth of both 2H- and 1T'-MoTe2 ML by molecular-beam epitaxy (MBE) and demonstrate its tenability by changing the conditions of MBE...
February 22, 2017: ACS Nano
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