The impact of process water on the surface properties of magnetite as measured by the zeta potential and through leaching experiments

2012 ◽  
Vol 29 (4) ◽  
pp. 199-206
Author(s):  
M. Westerstrand ◽  
A. Fredriksson ◽  
A. Holmgren ◽  
B. Öhlander
Keyword(s):  
Zeta Potential ◽  
Surface Properties ◽  
Process Water ◽  
Leaching Experiments ◽  
The Impact

scholarly journals Dye Separation and Antibacterial Activities of Polyaniline Thin Film-Coated Poly(phenyl sulfone) Membranes

Membranes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Javed Alam ◽  
Arun Kumar Shukla ◽  
Mohammad Azam Ansari ◽  
Fekri Abdulraqeb Ahmed Ali ◽  
Mansour Alhoshan
Keyword(s):  
Zeta Potential ◽  
Surface Properties ◽  
Antibacterial Activities ◽  
Pani Film ◽  
Force Microscopy ◽  
Water Permeation ◽  
Membrane Pores ◽  
Membrane Performance ◽  
Phenyl Sulfone ◽  
The Impact

We fabricated a nanofiltration membrane consisting of a polyaniline (PANI) film on a polyphenylsulfone (PPSU) substrate membrane. The PANI film acted as a potent separation enhancer and antimicrobial coating. The membrane was analyzed via scanning electron microscopy and atomic force microscopy to examine its morphology, topography, contact angle, and zeta potential. We aimed to investigate the impact of the PANI film on the surface properties of the membrane. Membrane performance was then evaluated in terms of water permeation and rejection of methylene blue (MB), an organic dye. Coating the PPSU membrane with a PANI film imparted significant advantages, including finely tuned nanometer-scale membrane pores and tailored surface properties, including increased hydrophilicity and zeta potential. The PANI film also significantly enhanced separation of the MB dye. The PANI-coated membrane rejected over 90% of MB with little compromise in membrane permeability. The PANI film also enhanced the antimicrobial activity of the membrane. The bacteriostasis (BR) values of PANI-coated PPSU membranes after six and sixteen hours of incubation with Escherichia coli were 63.5% and 95.2%, respectively. The BR values of PANI-coated PPSU membranes after six and sixteen hours of incubation with Staphylococcus aureus were 70.6% and 88.0%, respectively.

scholarly journals Modified Carbon Nanotubes: Surface Properties and Activity in Oxygen Reduction Reaction

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1354
Author(s):  
Vera Bogdanovskaya ◽  
Inna Vernigor ◽  
Marina Radina ◽  
Vladimir Sobolev ◽  
Vladimir Andreev ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Zeta Potential ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Surface Area ◽  
Surface Properties ◽  
Reduction Reaction ◽  
Wave Potential ◽  
Half Wave Potential ◽  
Half Wave

In order to develop highly efficient and stable catalysts for oxygen reduction reaction (ORR) that do not contain precious metals, it is necessary to modify carbon nanotubes (CNT) and define the effect of the modification on their activity in the ORR. In this work, the modification of CNTs included functionalization by treatment in NaOH or HNO3 (soft and hard conditions, respectively) and subsequent doping with nitrogen (melamine was used as a precursor). The main parameters that determine the efficiency of modified CNT in ORR are composition and surface area (XPS, BET), hydrophilic–hydrophobic surface properties (method of standard contact porosimetry (MSP)) and zeta potential (dynamic light scattering method). The activity of CNT in ORR was assessed following half-wave potential, current density within kinetic potential range and the electrochemically active surface area (SEAS). The obtained results show that the modification of CNT with oxygen-containing groups leads to an increase in hydrophilicity and, consequently, SEAS, as well as the total (overall) current. Subsequent doping with nitrogen ensures further increase in SEAS, higher zeta potential and specific activity in ORR, reflected in the shift of the half-wave potential by 150 mV for CNTNaOH-N and 110 mV for CNTHNO3-N relative to CNTNaOH and CNTHNO3, respectively. Moreover, the introduction of N into the structure of CNTHNO3 increases their corrosion stability.

Investigation on the recycling of sulfuric acid from pretreatment of cellulose for nanocellulose preparation

TAPPI Journal ◽  
2020 ◽  
Vol 19 (2) ◽  
pp. 103-111
Author(s):  
CHAOYU DUAN ◽  
YANGYANG PENG ◽  
SHIYU FU ◽  
LUCIAN LUCIA
Keyword(s):  
Thermal Stability ◽  
Sulfuric Acid ◽  
Zeta Potential ◽  
Surface Properties ◽  
Value Chain ◽  
Solid Residue ◽  
Number Of Cycles ◽  
The Relationship

Sulfuric acid is often used to pretreat cellulose prior to homogenization and conversion to nanocellulose. It would be economically significant to reuse the acid to close the overall value chain loop. The target of this work was to investigate the effect of recovery and recycling frequency of sulfuric acid from the pretreatments on the pretreatment yield of water-insoluble cellulose solid residue, and to explore the relationship between the nanocellulose size prepared by recovery of acid and number of cycles. The surface properties of the nanocelluloses were measured, including content of sulfate groups, absolute zeta potential, crystallinity, and thermal stability.

scholarly journals The Effect of the Ionic Strength of Process Water on the Interaction of Talc and CMC: Implications of Recirculated Water on Floatable Gangue Depression

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 231 ◽  
Author(s):  
Malibongwe Manono ◽  
Kirsten Corin ◽  
Jenny Wiese
Keyword(s):  
Ionic Strength ◽  
Zeta Potential ◽  
Saline Water ◽  
Process Water ◽  
Gangue Mineral ◽  
Mineral Surface ◽  
Base Interaction ◽  
Long Run ◽  
Complex Process ◽  
Closed Water

Previous studies speculate that hydroxo species present in flotation pulps at pH > 9, particularly those of polyvalent cations, selectively adsorb onto gangue minerals. Such species supposedly enhance the depressive action of carboxymethyl cellulose (CMC) onto gangue via an acid-base interaction between the positively charged mineral surface and the negatively charged CMC molecule. Thus, the hydrophilicity of gangue minerals is enhanced, preventing the dilution of the concentrate. However, as there is little evidence to support these claims for complex process waters of increasing ionic strength, it is important to investigate. Adsorption data and mineral surface charge analyses provide a fundamental understanding of how electrolytes and their ionic strengths affect gangue mineral-depressant adsorption. It is strongly anticipated that decoupling these effects will allow process operators to tailor their process water quality needs towards best flotation operating regimes and, in the long run, effect closed water circuits. Thus, using talc as a proxy for naturally floatable gangue common in sulfidic Cu–Ni–PGM ores, this work investigates the influence of the ionic strength of process water on the adsorption of CMC onto talc for a perspective on how saline water in sulfidic ores would affect the behavior and therefore management of floatable gangue. In the presence of CMC, the microflotation results showed that the rate of talc recovery decreased with increasing ionic strength of process water. Increases in ionic strength resulted in an increase in the adsorption of CMC onto talc. Talc particles proved to have been more coagulated at higher ionic strength since the settling time decreased with increasing ionic strength. Furthermore, the zeta potential of talc particles became less negative at higher ionic strengths of process water. It is thus proposed that increases in the ionic strength of process water increased the zeta potential of talc particles, enhancing the adsorption of CMC onto talc. This in turn created a more coagulated nature on talc particles, increasing their hydrophilicity and thereby retarding floatability.

Effects of Potassium-Dissolution Microorganisms on Surface Properties of Orthoclase and Bioleaching

2013 ◽  
Vol 753-755 ◽  
pp. 109-113
Author(s):  
Shou Fa Zhan ◽  
Ye Chen ◽  
De Si Sun
Keyword(s):  
Aspergillus Niger ◽  
Zeta Potential ◽  
Surface Properties ◽  
Stable Phase ◽  
Logarithmic Phase ◽  
Bacillus Mucilaginosus ◽  
Adsorption Studies

The alternation of surface properties of orthoclase after biological conditioning with Bacillus mucilaginosus and Aspergillus niger was investigated by zeta potential and adsorption studies. Bioleaching potassium from orthoclase by the two strains were also studied. Results show that IEPs of the two strain continuously decrease in their each logarithmic phase and stable phase. the IEP of orthoclase, after which interaction with cells, moves towords the IEP of cells. The adsorption of B·mucilaginosus is faster and higher than Aspergillus niger onto orthoclase. The potassium extractions by adapted B·mucilaginosus and unadapted B·mucilaginosus reach 24.0% and 18.5% respectively, 23.0% and 20.0% respectively by adapted Aspergillus niger and unadapted Aspergillus niger after bioleaching 9 d.

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