The Effect of Surface Charge on the Separation of Pyrite from Serpentine by Flotation

Serpentine, a magnesium silicate mineral with positive surface charge in many sulfide ores around the world, usually deteriorates the flotation behavior by covering the target mineral surface. In this paper, the effect of surface potential regulation on serpentine flotation was revealed by flocculation experiments, zeta potential measurements, infrared spectrum analysis, and DLVO theoretical calculations. The experimental results of flocculation and sedimentation show that heterogeneous coagulation easily occurs between serpentine and pyrite particles, which reduces the floatability of pyrite. Reducing the surface potential of serpentine is an effective way to eliminate heterogeneous coagulation between minerals. The key to regulating the surface potential of serpentine is Mg2+ ion dissolution from the serpentine surface to the liquid phase. Phosphates, especially sodium hexametaphosphate, can enhance Mg2+ ion dissolution from the serpentine surface to the liquid phase and react with Mg2+ ions in the liquid phase to form stable soluble complexes.

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Titania membranes for liquid phase separation: effect of surface charge on flux

Separation and Purification Technology ◽

10.1016/s1383-5866(01)00057-0 ◽

2001 ◽

Vol 25 (1-3) ◽

pp. 307-314 ◽

Cited By ~ 69

Author(s):

Toshinori Tsuru ◽

Daisuke Hironaka ◽

Tomohisa Yoshioka ◽

Masashi Asaeda

Keyword(s):

Phase Separation ◽

Liquid Phase ◽

Surface Charge ◽

Liquid Phase Separation ◽

Separation Effect ◽

Effect Of Surface

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EFFECTS OF POLYMERIC NANOPARTICLE SURFACE PROPERTIES ON INTERACTION WITH BRAIN TUMOR ENVIRONMENT

Nano LIFE ◽

10.1142/s1793984413430034 ◽

2013 ◽

Vol 03 (04) ◽

pp. 1343003 ◽

Cited By ~ 7

Author(s):

BRANDON MATTIX ◽

THOMAS MOORE ◽

OLGA UVAROV ◽

SAMUEL POLLARD ◽

LAUREN O'DONNELL ◽

...

Keyword(s):

Human Brain ◽

Surface Charge ◽

Cellular Uptake ◽

Drug Clearance ◽

Cellular Interaction ◽

Normal Tissues ◽

Poly Ethylene ◽

Uptake Studies ◽

Effect Of Surface

Current chemotherapy treatments are limited by poor drug solubility, rapid drug clearance and systemic side effects. Additionally, drug penetration into solid tumors is limited by physical diffusion barriers [e.g., extracellular matrix (ECM)]. Nanoparticle (NP) blood circulation half-life, biodistribution and ability to cross extracellular and cellular barriers will be dictated by NP composition, size, shape and surface functionality. Here, we investigated the effect of surface charge of poly(lactide)-poly(ethylene glycol) NPs on mediating cellular interaction. Polymeric NPs of equal sizes were used that had two different surface functionalities: negatively charged carboxyl ( COOH ) and neutral charged methoxy ( OCH 3). Cellular uptake studies showed significantly higher uptake in human brain cancer cells compared to noncancerous human brain cells, and negatively charged COOH NPs were uptaken more than neutral OCH 3 NPs in 2D culture. NPs were also able to load and control the release of paclitaxel (PTX) over 19 days. Toxicity studies in U-87 glioblastoma cells showed that PTX-loaded NPs were effective drug delivery vehicles. Effect of surface charge on NP interaction with the ECM was investigated using collagen in a 3D cellular uptake model, as collagen content varies with the type of cancer and the stage of the disease compared to normal tissues. Results demonstrated that NPs can effectively diffuse across an ECM barrier and into cells, but NP mobility is dictated by surface charge. In vivo biodistribution of OCH 3 NPs in intracranial tumor xenografts showed that NPs more easily accumulated in tumors with less collagen. These results indicate that a robust understanding of NP interaction with various tumor environments can lead to more effective patient-tailored therapies.

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The new approach in the determination of the dependency of surface charge density on semiconductor surface potential based voltage: capacity analysis of the depletion region of MIS-structures

10.1117/12.802478 ◽

2008 ◽

Author(s):

G. V. Chucheva ◽

A. G. Zhdan

Keyword(s):

Charge Density ◽

Surface Charge ◽

Surface Potential ◽

Surface Charge Density ◽

Depletion Region ◽

Semiconductor Surface ◽

Capacity Analysis ◽

New Approach ◽

Mis Structures

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The experimental determination of hydromagnesite precipitation rates at 22.5–75ºC

Mineralogical Magazine ◽

10.1180/minmag.2014.078.6.07 ◽

2014 ◽

Vol 78 (6) ◽

pp. 1405-1416 ◽

Cited By ~ 11

Author(s):

U.-N. Berninger ◽

G. Jordan ◽

J. Schott ◽

E. H. Oelkers

Keyword(s):

Low Temperature ◽

Experimental Determination ◽

Closed System ◽

Equilibrium Constants ◽

Magnesium Silicate ◽

Silicate Mineral ◽

Dissolution Rates ◽

Dissolution And Precipitation

Natural hydromagnesite (Mg5(CO3)4(OH)2·4H2O) dissolution and precipitation experiments were performed in closed-system reactors as a function of temperature from 22.5 to 75ºC and at 8.6 < pH < 10.7. The equilibrium constants for the reaction Mg5(CO3)4(OH)2·4H2O + 6H+ = 5Mg2+ + 4HCO3– + 6H2O were determined by bracketing the final fluid compositions obtained from the dissolution and precipitation experiments. The resulting constants were found to be 1033.7±0.9, 1030.5±0.5 and 1026.5±0.5 at 22.5, 50 and 75ºC, respectively. Whereas dissolution rates were too fast to be determined from the experiments, precipitation rates were slower and quantified. The resulting BET surface areanormalized hydromagnesite precipitation rates increase by a factor of ~2 with pH decreasing from 10.7 to 8.6. Measured rates are approximately two orders of magnitude faster than corresponding forsterite dissolution rates, suggesting that the overall rates of the low-temperature carbonation of olivine are controlled by the relatively sluggish dissolution of the magnesium silicate mineral.

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