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961.
Biosorption of Cr(VI) ions from aqueous solutions: kinetics, equilibrium, thermodynamics and desorption studies 总被引:2,自引:0,他引:2
Cr(VI) is a major water pollutant from industrial effluent whose concentration is to be reduced within the permissible limit. Present study reports a systematic evaluation of six different natural adsorbents for the removal of Cr(VI) from aqueous solutions in batch process. The adsorption kinetic data were best described by pseudo-second order model. The values of mass transfer coefficient for Cr(VI) adsorption indicated that the velocity of the adsorbate transport from the bulk to the solid phase was quite fast. The effective diffusivity of Cr(VI) removal for all the adsorbents were of the order of 10(-10) m(2)/s which suggested chemisorption of the process. The adsorption process was jointly controlled by film diffusion and intraparticle diffusion. Maximum monolayer adsorption capacities onto the natural adsorbents used were comparable to the other natural adsorbents used by other researchers. The thermodynamic studies and sorption energy calculation using Dubinin-Radushkevich isotherm model indicated that the adsorption processes were endothermic and chemical in nature. FT-IR studies were carried out to understand the type of functional groups responsible for Cr(VI) binding process. Desorption study was carried out with different concentration of NaOH solutions. Application study was carried out using electroplating industrial wastewater. 相似文献
962.
Efficacious Anticancer Drug Delivery Mediated by a pH‐Sensitive Self‐Assembly of a Conserved Tripeptide Derived from Tyrosine Kinase NGF Receptor 下载免费PDF全文
Parikshit Moitra Krishan Kumar Prof. Paturu Kondaiah Prof. Santanu Bhattacharya 《Angewandte Chemie (International ed. in English)》2014,53(4):1113-1117
We present herein a short tripeptide sequence (Lys–Phe–Gly or KFG) that is situated in the juxtamembrane region of the tyrosine kinase nerve growth factor (Trk NGF) receptors. KFG self‐assembles in water and shows a reversible and concentration‐dependent switching of nanostructures from nanospheres (vesicles) to nanotubes, as evidenced by dynamic light scattering, transmission electron microscopy, and atomic force microscopy. The morphology change was associated with a transition in the secondary structure. The tripeptide vesicles have inner aqueous compartments and are stable at pH 7.4 but rupture rapidly at pH≈6. The pH‐sensitive response of the vesicles was exploited for the delivery of a chemotherapeutic anticancer drug, doxorubicin, which resulted in enhanced cytotoxicity for both drug‐sensitive and drug‐resistant cells. Efficient intracellular release of the drug was confirmed by fluorescence‐activated cell sorting analysis, fluorescence microscopy, and confocal microscopy. 相似文献
963.
Convenient and straightforward tetrabutylammonium bromide (TBAB), benzyltrienthylammonium chloride (BTEAC), and cetyltrimethylammonium bromide (CTAB) catalyzed synthesis of 1,4-dihydropyridines (1,4-DHPs) in water was established for the first time. The catalytic potential of phase-transfer catalysts (PTCs) in three different concentrations was envisioned. Aryl aldehydes and hetero aryl aldehydes afforded good yields of 1,4-DHPs in TBAB and BTEAC reactions. In particular, furfuraldehyde and thienyl-2-carbaldehyde produced excellent yields. Isolation of the products through nonchromatographic methods, good to excellent yields, and benign reaction conditions are the major advantages of this protocol. 相似文献
964.
Poulomi Majumdar Anita Pati Rajani K. Behera Ajaya Kumar Behera 《Journal of heterocyclic chemistry》2013,50(3):703-712
A Cannizzaro‐type reaction of tetrahydro‐5(1H)‐quinolinones with para substituted benzaldehydes in the presence of a base formed the corresponding quinoline and aryl methanol rather than arylidene derivatives because of the oxidation of tetrahydroquinoline and reduction of benzaldehydes as a result of unprecedented hydride transfer from tetrahydroquinoline to arylaldehydes. The reaction proceeds best with the participation of substituents with +M effect in substrate molecule. 相似文献
965.
966.
An electrochemical pathway to prepare circular planar 90Sr/90Y sources for the calibration of surface contamination monitors 总被引:1,自引:0,他引:1
Manoj Kumar Shyamala S. Gandhi J. Nuwad J. Udhayakumar Ashutosh Dash 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):709-719
In this communication, we describe a novel method to prepare circular planar 90Sr/90Y sources (? = 16 mm) exploiting the intrinsic properties of the anodized titanium to electro-deposit predicted quantity of 90Sr activity from an aqueous solution. The influences of various experimental parameters such as pH of the electrolyte, applied current density, electrodeposition time and carrier strontium concentration were thoroughly investigated to arrive at a condition resulting optimal deposition of the 90Sr/90Y activity on the substrate. An optimized electrochemical procedure to prepare ~3.7 MBq (~0.1 mCi) of circular planar 90Sr/90Y sources commensurate with regulatory safety requirement has been the positive outcome. 相似文献
967.
Theodosis Giousis Georgia Potsi Antonios Kouloumpis Konstantinos Spyrou Yiannis Georgantas Nikolaos Chalmpes Konstantinos Dimos Myrsini‐Kiriaki Antoniou Georgios Papavassiliou Athanasios B. Bourlinos Hae Jin Kim Vijay Kumar Shankarayya Wadi Saeed Alhassan Majid Ahmadi Bart J. Kooi Graeme Blake Daniel M. Balazs Maria A. Loi Dimitrios Gournis Petra Rudolf 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2021,133(1):364-369
Germanane (GeH), a germanium analogue of graphane, has recently attracted considerable interest because its remarkable combination of properties makes it an extremely suitable candidate to be used as 2D material for field effect devices, photovoltaics, and photocatalysis. Up to now, the synthesis of GeH has been conducted by substituting Ca by H in a β‐CaGe2 layered Zintl phase through topochemical deintercalation in aqueous HCl. This reaction is generally slow and takes place over 6 to 14 days. The new and facile protocol presented here allows to synthesize GeH at room temperature in a significantly shorter time (a few minutes), which renders this method highly attractive for technological applications. The GeH produced with this method is highly pure and has a band gap (Eg) close to 1.4 eV, a lower value than that reported for germanane synthesized using HCl, which is promising for incorporation of GeH in solar cells. 相似文献
968.
Zexi Liu Jing Ai Prashant Kumar Enming You Xiong Zhou Xi Liu Zhongqun Tian Petr Bou Yingying Duan Lu Han Nicholas A. Kotov Songyuan Ding Shunai Che 《Angewandte Chemie (International ed. in English)》2020,59(35):15226-15231
A surface‐enhanced Raman scattering‐chiral anisotropy (SERS‐ChA) effect is reported that combines chiral discrimination and surface Raman scattering enhancement on chiral nanostructured Au films (CNAFs) equipped in the normal Raman scattering Spectrometer. The CNAFs provided remarkably higher enhancement factors of Raman scattering (EFs) for particular enantiomers, and the SERS intensity was proportional to the enantiomeric excesses (ee) values. Except for molecules with mesomeric species, all of the tested enantiomers exhibited high SERS‐ChA asymmetry factors (g), ranging between 1.34 and 1.99 regardless of polarities, sizes, chromophores, concentrations and ee. The effect might be attributed to selective resonance coupling between the induced electric and magnetic dipoles associated with enantiomers and chiral plasmonic modes of CNAFs. 相似文献
969.
In Vivo Endoscopic Tissue Identification by Rapid Evaporative Ionization Mass Spectrometry (REIMS) 下载免费PDF全文
Dr. Julia Balog Dr. Sacheen Kumar James Alexander Ottmar Golf Dr. Juzheng Huang Tom Wiggins Nima Abbassi‐Ghadi Dr. Attila Enyedi Dr. Sandor Kacska James Kinross Prof. George B. Hanna Prof. Jeremy K. Nicholson Prof. Zoltan Takats 《Angewandte Chemie (International ed. in English)》2015,54(38):11059-11062
Gastrointestinal cancers are a leading cause of mortality, accounting for 23 % of cancer‐related deaths worldwide. In order to improve outcomes from these cancers, novel tissue characterization methods are needed to facilitate accurate diagnosis. Rapid evaporative ionization mass spectrometry (REIMS) is a technique developed for the in vivo classification of human tissue through mass spectrometric analysis of aerosols released during electrosurgical dissection. This ionization technique was further developed by utilizing surface induced dissociation and was integrated with an endoscopic polypectomy snare to allow in vivo analysis of the gastrointestinal tract. We tested the classification performance of this novel endoscopic REIMS method in vivo. It was shown to be capable of differentiating between healthy layers of the intestinal wall, cancer, and adenomatous polyps based on the REIMS fingerprint of each tissue type in vivo. 相似文献
970.
Self‐Pillared,Single‐Unit‐Cell Sn‐MFI Zeolite Nanosheets and Their Use for Glucose and Lactose Isomerization 下载免费PDF全文
Dr. Limin Ren Dr. Qiang Guo Prashant Kumar Marat Orazov Dandan Xu Prof. Saeed M. Alhassan Prof. K. Andre Mkhoyan Prof. Mark E. Davis Prof. Michael Tsapatsis 《Angewandte Chemie (International ed. in English)》2015,54(37):10848-10851
Single‐unit‐cell Sn‐MFI, with the detectable Sn uniformly distributed and exclusively located at framework sites, is reported for the first time. The direct, single‐step, synthesis is based on repetitive branching caused by rotational intergrowths of single‐unit‐cell lamellae. The self‐pillared, meso‐ and microporous zeolite is an active and selective catalyst for sugar isomerization. High yields for the conversion of glucose into fructose and lactose to lactulose are demonstrated. 相似文献