Electromagnetophoretic Dynamic Force Measurement of Particle-Wall Interaction in Solution; Effects of pH and Metal Ions

Sorption and preconcentration of Cu2+, Zn2+ and Fe3+ on a salen-type Schiff base, 2,2'- [ethane-1,2-diylbis(nitrilomethylidyne)]bis(2-methylphenol), chemically immobilized on a highly crosslinked agarose support, were studied. Kinetic studies showed higher sorption rates of Cu2+ and Fe3+ in comparison with Zn2+. Half-times (t1/2) of 31, 106 and 58 s were obtained for sorption of Cu2+, Zn2+ and Fe3+ by the sorbent, respectively. Effects of pH, eluent concentration and volume, ionic strength, buffer concentration, sample volume and interferences on the recovery of the metal ions were investigated. A 5-ml portion of 0.4 M HCl solution was sufficient for quantitative elution of the metal ions from 0.5 ml of the sorbent packed in a 6.5 mm i.d. glass column. Quantitative recoveries were obtained in a pH range 5.5-6.5 for all the analytes. The volumes to be concentrated exceeding 500 ml, ionic strengths as high as 0.5 mol l-1, and acetate buffer concentrations up to 0.3 mol l-1 for Zn2+ and 0.4 mol l-1 for Cu2+ and Fe3+ did not have any significant effect on the recoveries. The system tolerated relatively high concentrations of diverse ions. Preconcentration factors up to 100 and detection limits of 0.31, 0.16 and 1.73 μg l-1 were obtained for Cu2+, Zn2+ and Fe3+, respectively, for their determination by a flame AAS instrument. The method was successfully applied to the metal ion determinations in several river water samples with good accuracy.

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Antibacterial Activity and Mode of Action of Dihydromyricetin from Ampelopsis grossedentata Leaves against Food-Borne Bacteria

Molecules ◽

10.3390/molecules24152831 ◽

2019 ◽

Vol 24 (15) ◽

pp. 2831 ◽

Cited By ~ 7

Author(s):

Xiao-Nian Xiao ◽

Fan Wang ◽

Yi-Ting Yuan ◽

Jing Liu ◽

Yue-Zhen Liu ◽

...

Keyword(s):

Antibacterial Activity ◽

Metal Ions ◽

Thermal Processing ◽

Tricarboxylic Acid Cycle ◽

Tricarboxylic Acid ◽

Respiratory Metabolism ◽

Food Borne ◽

Effects Of Ph ◽

Health Promoting ◽

Ampelopsis Grossedentata

Dihydromyricetin (DMY) has recently attracted increased interest due to its considerable health-promoting activities but there are few reports on its antibacterial activity and mechanism. In this paper, the activity and mechanisms of DMY from Ampelopsis grossedentata leaves against food-borne bacteria are investigated. Moreover, the effects of pH, thermal-processing, and metal ions on the antibacterial activity of DMY are also evaluated. The results show that DMY exhibits ideal antibacterial activity on five types of food-borne bacteria (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Salmonella paratyphi, and Pseudomonas aeruginosa). The activities of DMY against bacteria are extremely sensitive to pH, thermal-processing, and metal ions. The morphology of the tested bacteria is changed and damaged more seriously with the exposure time of DMY. Furthermore, the results of the oxidative respiratory metabolism assay and the integrity of the cell membrane and wall tests revealed that the death of bacteria caused by DMY might be due to lysis of the cell wall, leakage of intracellular ingredients, and inhibition of the tricarboxylic acid cycle (TCA) pathway.

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Preparation and Characterization of Nanoporous Activated Carbon Derived from Prawn Shell and Its Application for Removal of Heavy Metal Ions

Materials ◽

10.3390/ma12020241 ◽

2019 ◽

Vol 12 (2) ◽

pp. 241 ◽

Cited By ~ 17

Author(s):

Jian Guo ◽

Yaqin Song ◽

Xiaoyang Ji ◽

Lili Ji ◽

Lu Cai ◽

...

Keyword(s):

Heavy Metal ◽

Activated Carbon ◽

Metal Ions ◽

Heavy Metal Ions ◽

Ph Value ◽

Average Pore Size ◽

High Specific Surface Area ◽

Koh Activation ◽

Average Pore ◽

Effects Of Ph

The aim of this study was to optimize the adsorption performance of activated carbon (AC), derived from the shell of Penaeus vannamei prawns, on heavy metal ions. Inexpensive, non-toxic, and renewable prawn shells were subjected to carbonization and, subsequently, KOH-activation to produce nanoporous K-Ac. Carbonized prawn shells (CPS) and nanoporous KOH-activated carbon (K-Ac) from prawn shells were prepared and characterized by FTIR, XRD, BET, SEM, and TEM. The results showed that as-produced K-Ac samples were a porous material with microporous and mesoporous structures and had a high specific surface area of 3160 m2/g, average pore size of about 10 nm, and large pore volume of 2.38 m3/g. Furthermore, batches of K-Ac samples were employed for testing the adsorption behavior of Cd2+ in solution. The effects of pH value, initial concentration, and adsorption time on Cd2+ were systematically investigated. Kinetics and isotherm model analysis of the adsorption of Cd2+ on K-Ac showed that experimental data were not only consistent with the Langmuir adsorption isotherm, but also well-described by the quasi-first-order model. Finally, the adsorption behaviors of as-prepared K-Ac were also tested in a ternary mixture of heavy metal ions Cu2+, Cr6+, and Cd2+, and the total adsorption amount of 560 mg/g was obtained.

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Dynamic Force Measurement of Model Container to Centrifuge Nacelle Used in Centrifuge Model Explosion Test

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.439-440.1393 ◽

2010 ◽

Vol 439-440 ◽

pp. 1393-1397

Author(s):

Xiao Hong Yue ◽

Yong Jian Mao ◽

Hao Pu ◽

Bao Liang Niu ◽

Lei Wang ◽

...

Keyword(s):

Force Measurement ◽

Low Cost ◽

Dynamic Environment ◽

Dynamic Strain ◽

Centrifuge Model Test ◽

Dynamic Force ◽

Geotechnical Centrifuge ◽

Centrifuge Model ◽

Explosion Test ◽

Compressive Tests

The technique of centrifuge model test has been widely used in geotechnical mechanics and engineering because of its low cost and low test scale. In order to investigate the dynamic behaviors of the geotechnical model under explosion, we are developing an explosion geotechnical centrifuge. The dynamic environment of explosion is necessary to be determined for the strength design of the centrifuge nacelle. This paper presents the dynamic force measurement of the model container to the centrifuge nacelle under a typical explosion. Firstly, three cylindrical supports were designed and calibrated by quasi-static compressive tests. The force-strain relations are measured and linearly fitted. Secondly, an explosion test was performed and the dynamic strain histories of the supports were measured. Then the dynamic force histories were obtained combined with the calibration results. The investigation provides an understanding of the dynamic environment for the centrifuge nacelle design.

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Selective separation and recovery of silver and copper from mixtures by photocatalysis

International Journal of Modern Physics B ◽

10.1142/s0217979217440969 ◽

2017 ◽

Vol 31 (16-19) ◽

pp. 1744096

Author(s):

Mali Ding ◽

Weijun Zhang ◽

Zhaofeng Xie ◽

Rihua Lei ◽

Jianfang Wang ◽

...

Keyword(s):

Metal Ions ◽

Ethylene Diamine Tetraacetic Acid ◽

Uv Light ◽

Electronic Waste ◽

Experimental Results ◽

Tetraacetic Acid ◽

Selective Recovery ◽

Valuable Metals ◽

Effects Of Ph ◽

Environmental Importance

Separation and recovery of valuable metals including silver (Ag) and copper (Cu) from electronic waste mixtures are of great economic and environmental importance. Recent years, semiconductor photocatalysts have been investigated intensively for the removal of Ag from wastewater. Few studies have been carried out on the effect of pH and co-exist metal ions such as Cu on Ag. In this study, ZnO and TiO2 were applied as photocatalysts to target on the selective recovery Ag and Cu from its mixtures under UV light. The effects of pH, catalyst, ethylene-diamine tetraacetic acid (EDTA) on the Ag and Cu photo-reduction were studied. Modeling of Ag[Formula: see text] and Cu[Formula: see text] with and without EDTA distribution together with metal precipitations was plotted against pH to understand the chemistry involved in photocatalysis. Experimental results showed that Ag[Formula: see text] photo-reduction was nearly completed by ZnO and TiO2 to Ag metal, while Cu[Formula: see text] photo-reduction to Cu2O only occurs by ZnO in the presence of EDTA. This work illustrates that semiconductor photocatalysts are suitable for selective recovery of Ag and Cu from wastewaters.

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