The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Jinlin Yang - One of the best experts on this subject based on the ideXlab platform.
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Inorganic Anion modulated synthesis of 2d nonlayered aluminum based metal organic frameworks as carbon precursor for capacitive sodium ion storage
Energy Storage Materials, 2020Co-Authors: Jinlin Yang, Shuning Xiao, Xinhang Cui, Wenrui Dai, Xu Lian, Zhongkai Hao, Yong Zhao, Jisheng Pan, Yin ZhouAbstract:Abstract Metal-organic frameworks (MOFs) have been widely employed as the precursors to obtain functional carbon with tuneable composition and structure. However, the design of 2D carbon nanostructures directly from two-dimensional (2D) nonlayered MOFs is still very scarce, which is mainly hindered by the synthesis of 2D nonlayered MOFs. Herein, 2D nonlayered NH2-MIL-53 (Al) is synthesized via Inorganic Anion modulation for 2D S, N, O-rich hard carbon nanosheets (SNO-HCN) precursor. Due to the introduction of S-doping, more open edge sites generate, which accordingly promote the formation of pyridinic N and C=O carbonyl groups. When adopted as the anode for the sodium ion batteries, the SNO-HCN electrode delivers high reversible capacity of 522 mAh g−1 and 185 mAh g−1 at 50 mA g−1 and 15000 mA g−1, respectively. The enlarged interlayer spacing, unique 2D structure, heteroatom-rich active sites, and high surface area lead to the improved electrochemical performance. Furthermore, the galvanostatic intermittent titration technique (GITT) test indicates the superior electrochemical kinetics of the SNO-HCN electrode and the quantitative analysis reveals the capacitance contribution dominates during sodium-ion storage process. This represents an universal approach for the preparation of various 2D carbon nanomaterials derived from 2D nonlayered MOFs.
Charles A. Lucy - One of the best experts on this subject based on the ideXlab platform.
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selective preconcentration of chemical warfare agent degradation products using a zirconia preconcentration column
Journal of Chromatography A, 2008Co-Authors: Ting Zhou, Charles A. LucyAbstract:Abstract Zirconia (ZrO 2 ) has strong Lewis acid sites which have an affinity for the strongly electronegative phosphonate group of organo-phosphates. To investigate whether this affinity can be used for selective preconcentration, the retention of methyl, ethyl, and propylphosphonic acid (MPA, EPA and PPA) and Inorganic Anion matrix components on ZrO 2 was investigated. Only organo-phosphates and sulfate exhibited retention on zirconia. After preconcentration, the retained species were eluted from ZrO 2 by 0.75 mM Na 2 CO 3 , and separated by a Dionex Ionpac AS11 Anion-exchange column (250 mm × 2 mm I.D.) and a Hypercarb RPLC column (50 mm × 4.6 mm I.D., 3 μm) in series followed by suppressed conductivity detection. Calibration curve showed a linear response for MPA, EPA and PPA in the range of 0.01 μM to 1 μM ( R 2 > 0.9989). Detection limits after preconcentration of a 10 mL sample were 0.16, 0.19 and 0.16 μg/L for MPA, EPA, and PPA, respectively.
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semi permanent surfactant coatings for Inorganic Anion analysis in capillary electrophoresis
Journal of Chromatography A, 2002Co-Authors: Nicole E Baryla, Charles A. LucyAbstract:Capillary electrophoretic separations of Inorganic Anions are performed using a capillary coated with a mixture of the cationic surfactant didodecyldimethylammonium bromide (DDAB) and the zwitterionic surfactant 1,2-dilauroyl-sn-phosphatidylcholine (DLPC). These double-chained surfactants form semi-permanent coatings on the capillary wall, which allows the excess surfactant to be removed from the buffer prior to separation. Interactions between surfactant aggregates in the buffer and analyte Anions are thus eliminated. The electroosmotic flow (EOF) can be altered from fully reversed (100% DDAB) to near zero (100% DLPC) using different ratios of DDAB and DLPC. Controlling the EOF allows for improved resolution of the Anions while maintaining a rapid, co-EOF separation, free from analyte-surfactant additive interactions.
Russell J Hockett - One of the best experts on this subject based on the ideXlab platform.
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use of toxicity identification evaluation methods to characterize identify and confirm hexavalent chromium toxicity in an industrial effluent
Water Research, 2000Co-Authors: David R Mount, Russell J HockettAbstract:Abstract A toxicity identification evaluation (TIE) was conducted on effluent from a major industrial discharger. Although initial monitoring typically showed only slight, intermittent, chronic toxicity to Ceriodaphnia dubia, a later sample showed substantial acute toxicity to C. dubia (48-h lc 50=9%). Acute phase I toxicity characterization tests were conducted on this acutely toxic sample; none of the phase I manipulations reduced sample toxicity. The toxic effluent sample was then treated with activated carbon, and cation, Anion, and mixed-bed ion exchange. Acute toxicity was not reduced by treatment with activated carbon or cation exchange, but was completely removed by Anion and mixed-bed ion exchange. Based on these data, we concluded that the causative toxicant(s) was likely an Inorganic Anion(s); chemical analysis detected hexavalent chromium (Cr[VI]) at concentrations sufficient to account for the observed acute toxicity. Although Cr[VI] could clearly explain the presence of acute toxicity, subsequent confirmation testing was designed to determine whether Cr[IV] was responsible for the low-level chronic toxicity more typical of the effluent. Concurrent chronic tests conducted on unaltered and Anion-exchanged effluent showed that the presence of chronic toxicity was associated with chronically toxic concentrations of Cr[VI]. The source of Cr[VI] in the effluent was traced to a malfunctioning heat exchanger; after this malfunction was corrected, neither chronic toxicity nor appreciable Cr[VI] was observed in the effluent again.
Yan Zhu - One of the best experts on this subject based on the ideXlab platform.
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an electrodialytic device for automated Inorganic Anion preconcentration with determination by ion chromatography conductivity detection
Journal of Chromatography A, 2021Co-Authors: Ning Chen, Yan ZhuAbstract:A 4-layer sandwiched device (4LSD) well suited for coupling to online ion chromatography (IC) systems was described and simultaneously performed target Anion enrichment, matrix removal and sample injection within seconds. The basic assembly consisted of an extraction solution channel, a sample solution channel and two electrolyte channels. Cation-exchange resin (CER) was utilized to support the solution chamber, increase electrical conductivity and improve pressure resistance to achieve compatibility with a peristaltic pump. Filter placement ensured loop circulation of the 4LSD and prevented resin leakage. The 4LSD showed comparable performance to that of conventional solid-phase extraction (SPE) pretreatment in terms of matrix interference removal while enabling automation. The applied current, sample/extraction solution flow rate ratio, and initial concentration were discussed and optimized. Controllable 1-40-fold enrichment can be ensured. The migration phenomenon of different Anions was discussed. F-, Cl-, NO2-, Br-, NO3-, SO42- and ClO4- exhibited satisfactory linear detection ranges within 2.5-1000 μg·L-1, and the calculated limits of detection (LODs) in milk formula were within the 0.097-0.79 mg·kg-1 range. The 4LSD was successfully applied to the determination of Anions in milk formula with good spiked recoveries ranging between 92.54% and 107.2%, except for the NO2- recovery. The relative standard deviations (RSDs) ranged from 0.69% to 8.29%.
Ming Chen - One of the best experts on this subject based on the ideXlab platform.
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Inorganic Anion removal using micellar enhanced ultrafiltration meuf modeling Anion distribution and suggested improvements of meuf a review
Chemical Engineering Journal, 2020Co-Authors: Ming Chen, Chad T Jafvert, Xiaoqiang Cao, Nicholas P HankinsAbstract:Abstract Surfactants have been used often in environmental remediation strategies due to their special amphiphilic nature which alters surface and water interfacial properties. When the aqueous concentration of a cationic surfactant far exceeds the critical micelle concentration (CMC), a large concentration of cationic micelles will form in water. These micelles each consist of tens to hundreds of surfactant monomers, and collectively can be utilized as nano-sized ion exchangers to assist with ultrafiltration separation (i.e., removal) of Anionic pollutants from natural waters or wastewaters. Target Anionic pollutants include nitrate, phosphate, arsenate and chromate. However, most polluted waters contain a complex mixture of Anions, with these different Anions competing for the micellar pseudo-phase, thus potentially reducing the overall removal efficiency of the target Anions. Further, loss of surfactant monomers through the membrane also reduces process efficiency as replenishment of surfactant over time is required. In this review, the existing researches on Inorganic Anion removal by micellar enhanced ultrafiltration (MEUF) and similar processes are summarized. Operating condition factors are discussed, including pressure, membrane pore size, surfactant-contaminant concentration ratio, and water chemistry conditions (i.e., pH, salinity). Because most micellar surfactant – Anion interactions are through outer-sphere electrostatic association, emphases in this review are given to the measurement of selectivity coefficients used for identifying the affinity of Anions to the micelles, which generally decreases in the order of: Fe(CN)63− > CrO42− > SO42− > HAsO42− > HPO42− > NO3− > Br− > NO2− > Cl− > HCO3− > H2AsO4− > H2PO4− > F− > IO3−; and to the development of a speciation model, based on these selectivity coefficients, for predicting Anion distribution in micellar solutions. Ways to address improved process efficiency, as well as future challenges and opportunities, are also discussed.