scholarly journals Colloidal ZnCO3 as a Powerful Depressant of Arsenopyrite in Weakly Alkaline Pulp and the Interaction Mechanism

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 315
Author(s):  
Youguo Guan ◽  
Pingtian Ming ◽  
Zhuohong Xie ◽  
Fei Li ◽  
Qingqing Xing ◽  
...  
Keyword(s):  
Electrokinetic Potential ◽  
Interaction Mechanism ◽  
Sharp Decrease ◽  
Weakly Alkaline ◽  
Potential Measurement ◽  
Sem Observation ◽  
Adsorbed Amount ◽  
Zinc Carbonate ◽  
Measurement Results ◽  
Ph Range

The effects of ZnSO4 on arsenopyrite depression were studied with sodium carbonate and sodium isobutyl xanthate (SIBX) as the pH regulator and collector, respectively. In both micro and real ore flotation tests, ZnSO4 showed better depression on arsenopyrite (pH 7.5–9.0 adjusted by Na2CO3) compared with sodium humate. The depression mechanism of ZnSO4 on arsenopyrite flotation was studied by electrokinetic potential, adsorbed amount measurements, scanning electron microscope (SEM) observation and energy dispersive spectra (EDS) detection. The electrokinetic potential measurement results show a potential increase forpleas the arsenopyrite treated with ZnSO4 in the pH range 7.5–9.0, which could be attributed to the formation of the precipitated zinc carbonate (ZnCO3(S)). For arsenopyrite treated with both ZnSO4 and SIBX, the electric surface potentials also display an increase, to approximate the values with solely ZnSO4 treated, at pH 7.5–9.0, indicating the inhibition of ZnCO3(S) upon the SIBX adsorption onto arsenopyrite. Adsorption results demonstrated that SIBX adsorption onto arsenopyrite indeed was inhibited at the pH 7.5-9.0 through the sharp decrease in SIBX adsorbed amount with ZnSO4 as the depressant at this pH range. SEM observation and EDS detection results verify the formation of colloidal ZnCO3 on the arsenopyrite, with ZnSO4 as the depressant in combination with Na2CO3.

scholarly journals The Effect of pH and Concentration of KNO3 Solution to the Performance of Nd3+ Ion Selective Electrode Using HPMBP Ionophore

2018 ◽  
Vol 3 (3) ◽  
pp. 193
Author(s):  
Husain Sosidi ◽  
Buchari Buchari ◽  
Indra Noviandri
Keyword(s):  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Buffer Solution ◽  
Potential Measurement ◽  
Ph Variation ◽  
Measurement Results ◽  
Optimum Ph ◽  
Electrode Method ◽  
Potentiometric Analysis ◽  
Ph Range

<p>The phenyl-3-methyl-4-benzoyl-5-pyrazolone (HPMBP) synthesized and characterized as ionophore in potentiometric analysis of ion selective electrode method (ISE) with polytetrafluoroethylene (PTFE) as the supporting phase. The pH and concentration of the ionic strength adjuster (ISA) were varied to know at the optimum pH and concentration of the ion-selective electrode (ESI) KNO<sub>3</sub>, thus potential Nd<sup>3+</sup> gives the best performance. Before use the PTFE membrane was immersed in a chloroform-HPMBP solution of 1.5-2.0% w/v for 24 h. The pH variation of the buffer solution was adjusted to the pH range of 2-10 using HCl and NaOH solutions, whereas the concentration of KNO<sub>3</sub> varies from 10<sup>-1</sup> to 10<sup>-3</sup> M. The concentration range of Nd<sup>3+</sup> is between 10<sup>-2</sup> and 10<sup>-7</sup> M. The electrode potential measurement results (E<sub>Nd</sub>) obtained the best performance value at pH 4 with KNO<sub>3</sub> concentration of 10<sup>-2</sup> M, sensitivity (S) 18.39 ± 1.2 mV/decade and response time less than 23 s.</p>

scholarly journals Novel Selective Depressant of Titanaugite and Implication for Ilmenite Flotation

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 703 ◽  
Author(s):  
Liu ◽  
Wang ◽  
Xiao ◽  
Wang ◽  
Deng ◽  
...  
Keyword(s):  
Sodium Silicate ◽  
Iron Ore ◽  
Electrokinetic Potential ◽  
Sodium Polystyrene Sulfonate ◽  
Test Results ◽  
Polystyrene Sulfonate ◽  
Ilmenite Concentrate ◽  
Adsorbed Amount ◽  
Mineral Flotation ◽  
Adsorption Quantity

This paper studies the effects of sodium polystyrene sulfonate (PSSNa) used as a depressant upon the separation of ilmenite from titanaugite through flotation when sodium oleate (NaOl) is used as a collector by performing single mineral flotation experiments. The depression mechanism of PSSNa on titanaugite flotation was studied by electrokinetic potential and adsorbed amount measurements together with FTIR and XPS detection. Single mineral flotation experiments show that PSSNa is a selective depressant for the separation of ilmenite and titanaugite via flotation with NaOl as the collector. The results of the adsorbed amount tests show that the biggest distinction is in terms of the amount of NaOl adsorbed on the surfaces of ilmenite and titanaugite; the amount is expanded from 2.28 × 10−7 to 9.34 × 10−7 mol/m2 when the dosage of PSSNa is 1 mg/L, as compared with no PSSNa, suggesting that PSSNa is a selective depressant when separating ilmenite and titanaugite through flotation. FTIR testing shows that chemisorption has occurred between the –SO3− groups of the molecular PSSNa and titanaugite surfaces. The results of further XPS testing reveal that PSSNa chemically interacts with Ca/Mg/Al/Fe on the titanaugite surface. The test results of FTIR in combination with XPS confirm that PSSNa stops NaOl from interacting with Mg, Fe, Al, and Ca on the titanaugite surface, and this outcome is the main reason for the widening of the adsorption quantity gap of NaOl on titanaugite and ilmenite surfaces, and titanaugite flotation is suppressed. The results of the comparison flotation testing on actual Panzhihua titanic iron ore (TiO2 grade: 15.63%) with titanaugite as the main gangue show that a better effect is obtained by replacing sodium silicate (SS) with PSSNa, and the recovery of TiO2 using PSSNa is higher than that when using sodium silicate. In a closed circuit flotation test, ilmenite concentrate is obtained with a TiO2 grade of 45.97% and a recovery of 76.32% by using PSSNa as a titanaugite depressant.

scholarly journals Bentonite Nanoparticle Stability and the Effect of Fulvic Acids: Experiments and Modelling

2020 ◽  
Vol 4 (2) ◽  
pp. 16
Author(s):  
Holger Seher ◽  
Horst Geckeis ◽  
Thomas Fanghänel ◽  
Thorsten Schäfer
Keyword(s):  
Fulvic Acid ◽  
Electrokinetic Potential ◽  
Background Electrolyte ◽  
Fulvic Acids ◽  
Structural Formula ◽  
Stability Ratio ◽  
Potential Measurement ◽  
Ζ Potential ◽  
Scanning Transmission ◽  
The Stability

In this study, the critical coagulation concentration (CCC) for FEBEX bentonite colloids is determined by colloid coagulation studies under variation of pH, electrolyte concentration, and fulvic acid (GoHy-573FA) content. For CaCl2 electrolyte solution, a pH-independent Ca-CCC of 1 mmol L−1 is found. In the case of NaCl background electrolyte, a pH-dependent Na-CCC can be determined with 15 ± 5 mmol L−1 at pH 6, 20 ± 5 mmol L−1 at pH 7, 200 ± 50 mmol L−1 at pH 8, 250 ± 50 mmol L−1 at pH 9, and 350 ± 100 mmol L−1 at pH 10, respectively. The addition of 1 mg L−1 dissolved organic carbon in the form of fulvic acid (FA) increases the Ca-CCC to 2 mmol L−1. An association of FA with FEBEX bentonite colloids as surface coating can clearly be identified by scanning transmission X-ray microscopy (STXM). The experimental bentonite stability results are described by means of an extended DLVO (Derjaguin–Landau–Verwey–Overbeek) approach summing up hydration forces, short-range Born repulsion, van der Waals attraction, and electrical double layer repulsion. The measured zeta (ζ)-potential of the bentonite colloids is applied as platelet face electrokinetic potential and the edge electrokinetic potential is estimated by the combination of silica and alumina ζ-potential data in the ratio given by the FEBEX bentonite structural formula. Adjusting the montmorillonite face electrokinetic potential by a maximum of ±15.9 mV is sufficient to successfully reproduce the measured stability ratios. Due to the uncertainty in the ζ-potential measurement, only semiquantitative calculations of the stability ratio can be given.

scholarly journals Molecular Dynamics Simulations on the Demolding Process for Nanostructures in Injection Molding

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 636 ◽  
Author(s):  
Can Weng ◽  
Dongjiao Yang ◽  
Mingyong Zhou
Keyword(s):  
Molecular Dynamics ◽  
Injection Molding ◽  
Molecular Dynamics Simulations ◽  
Interaction Mechanism ◽  
Mold Insert ◽  
Sharp Decrease ◽  
Average Density ◽  
Radius Of Gyration ◽  
Good Shape ◽  
Dynamics Simulations

Injection molding is one of the most potential techniques for fabricating polymeric products in large numbers. The filling process, but also the demolding process, influence the quality of injection-molded nanostructures. In this study, nano-cavities with different depth-to-width ratios (D/W) were built and molecular dynamics simulations on the demolding process were conducted. Conformation change and density distribution were analyzed. Interfacial adhesion was utilized to investigate the interaction mechanism between polypropylene (PP) and nickel mold insert. The results show that the separation would first happen at the shoulder of the nanostructures. Nanostructures and the whole PP layer are both stretched, resulting in a sharp decrease in average density after demolding. The largest increase in the radius of gyration and lowest velocity can be observed in 3:1 nanostructure during the separation. Deformation on nanostructure occurs, but nevertheless the whole structure is still in good shape. The adhesion energy gets higher with the increase of D/W. The demolding force increases quickly to the peak point and then gradually decreases to zero. The majority of the force comes from the adhesion and friction on the nanostructure due to the interfacial interaction.

scholarly journals Enhanced virus filtration in hybrid membranes with MWCNT nanocomposite

2019 ◽  
Vol 6 (1) ◽  
pp. 181294 ◽  
Author(s):  
Zoltán Németh ◽  
Gergő Péter Szekeres ◽  
Mateusz Schabikowski ◽  
Krisztina Schrantz ◽  
Jacqueline Traber ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drinking Water ◽  
Electrostatic Interactions ◽  
Membrane Separation ◽  
Area Measurement ◽  
Hybrid Membranes ◽  
Potential Measurement ◽  
Virus Removal ◽  
Multi Walled Carbon Nanotubes ◽  
Ph Range

Membrane separation is proved to be a powerful tool for several applications such as wastewater treatment or the elimination of various microorganisms from drinking water. In this study, the efficiency of inorganic composite-based multi-walled carbon nanotube (MWCNT) hybrid membranes was investigated in the removal of MS2 bacteriophages from contaminated water. With this object, multi-walled carbon nanotubes were coated with copper(I) oxide, titanium(IV) oxide and iron(III) oxide nanoparticles, respectively, and their virus removal capability was tested in both batch and flow experiments. Considering the possible pH range of drinking water, the filtration tests were carried out at pH 5.0, 7.5 and 9.0 as well. The extent of MS2 removal strongly depended on the pH values for each composite, which can be due to electrostatic interactions between the membrane and the virus. The most efficient removal (greater than or equal to 99.99%) was obtained with the Cu 2 O-coated MWCNT membrane in the whole pH range. The fabricated nanocomposites were characterized by X-ray diffraction, specific surface area measurement, dynamic light scattering, zeta potential measurement, Raman spectroscopy, transmission electron microscopy and scanning electron microscopy. This study presents a simple route to design novel and effective nanocomposite-based hybrid membranes for virus removal.

scholarly journals Analisa Kualitas Air Budidaya Udang Vaname (Litopenaeus vannamei) di Tambak Rakyat Kontruksi Dinding Semen Dan Dasar Tambak Semen Di Pantai Konang, Kecamatan Panggul Kabupaten Trenggalek

2021 ◽  
Vol 12 (1) ◽  
pp. 80-85
Author(s):  
Musyaffa Rafiqie
Keyword(s):  
Water Quality ◽  
Smallholder Farmers ◽  
Pond Water ◽  
Quality Analysis ◽  
Optimal Temperature ◽  
Water Quality Analysis ◽  
Simple Tool ◽  
Measurement Results ◽  
Ph Range

The water quality analysis activities carried out by smallholder farmers with the construction of cement walls and cement pond bases on the Konang beach, Panggul District, Trenggalek Regency, have not met the standard standards in the analysis of pond water quality. Pond farmers only analyze the pH, brightness and temperature of the pond water. The research objective was to obtain information and describe the analysis of water quality in the community pond construction of cement walls and the bottom of cement ponds at Konang beach, Panggul District, Trenggalek Regency. The activity of analyzing the water quality of the community plots of construction of cement walls and the bottom of the cement ponds on the Konang beach, Panggul District, Trenggalek Regency, was observed in the form of temperature, brightness and pH, with a pond area of ​​250 m2. Water quality observation activities for 30 days, in one day water quality observations are made twice, namely in the morning and evening. The pH measurement results were obtained, ranging from 7.4 to 8.5, so that the results of measuring the pH of the water in the people's ponds in Koneng Beach were still normal or normal. According to Boyd (2001) in Andi S and Sahabuddin (2014), it is said that water organisms (fish or shrimp) require a pH range of 6.8 - 8.5. the results of measuring the brightness with a simple tool, the measurement results are between 25-40 cm. Badrudin et al (2014) stated that the optimum brightness level of pond water which is influenced by plankton density is around 20 - 40 cm. So that the level of brightness can be concluded that it is still in rational or optimal. The temperature in the ponds was 24 ᴼC - 28 ᴼC, still within normal or optimal. According to Supito (2017), the pond temperature in the range of 28 ᴼ C to 32 ᴼ C is the optimal temperature forcultivating vaname shrimp.

Steel Corrosion Patterns in Neutral and Alkaline Iron Oxide Slurry

2021 ◽  
pp. 142-155
Author(s):  
V.A. Shelontsev ◽  
I.G. Gorichev ◽  
A.V. Kuzin ◽  
I.V. Gerasimova ◽  
E.A. Eliseeva
Keyword(s):  
Iron Oxide ◽  
Corrosion Rate ◽  
Dissolved Oxygen ◽  
Polarization Resistance ◽  
Gravimetric Method ◽  
Sharp Decrease ◽  
Steel Corrosion ◽  
Chloride Ions ◽  
Diffusion Control ◽  
Ph Range

The study identifies and theoretically substantiates the steel corrosion patterns in aqueous slurry of iron-ore concentrate. The purpose of the study was to examine the effect that the content of dissolved oxygen(PO2), pH, the concentration of chloride ions (CCl-) and the rate of movement of the iron oxide slurry (ω) produce on the corrosion losses of steel 20. Comparative analysis of the corrosion rate values obtained by the gravimetric method and the polarization resistance method showed that the reciprocal of the polarization resistance and the corrosion rate change symbatically with increasing pH, the corrosion rate values are quantitatively well consistent with each other. To identify the corrosion patterns, the method of polarization resistance was used. The dependence of the corrosion rate (ρ) on рН revealed two characteristic areas: in the first one, there is no dependence of the rate on pH (6.5--9.0); in the second one, there is a sharp decrease in corrosion losses when the pH goes from 9.0 to 12.5. For pH = 6.5--9.0, the corrosion rate increases linearly with an increase in the partial pressure of oxygen, and corrosion losses in the slurry are higher than in the background solution. The dependence ρ(√ω) is linear over the entire pH range (6.0--9.0), which indicates the diffusion control of the corrosion process. Findings of research show that in order to protect carbon steel from corrosion in the iron oxide slurry, it is necessary to take into account the pH and О2 concentration. Optimal reduction of corrosion losses can be achieved by alkalizing the slurry and removing dissolved oxygen

scholarly journals Self-Assembled Nanocarriers Based on Modified Chitosan for Biomedical Applications: Preparation and Characterization

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2593 ◽  
Author(s):  
Alina Gabriela Rusu ◽  
Aurica P. Chiriac ◽  
Loredana Elena Nita ◽  
Irina Rosca ◽  
Daniela Rusu ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Conformational Changes ◽  
Self Assembly ◽  
Biomedical Applications ◽  
Antimicrobial Properties ◽  
Interaction Mechanism ◽  
Hydrodynamic Diameter ◽  
Potential Measurement ◽  
Modified Chitosan ◽  
Influence Of Temperature On

Protein-polysaccharide systems are of increasing interest as their combined attributes allow for fulfilling a broad range of applications in biomedical and pharmaceutical fields. In this study, the preparation of nanogels based on maleic anhydride chitosan derivatives (MAC) and bovine serum albumin (BSA) was achieved through a self-assembly process performed in aqueous phase. A series of experiments performed by varying the concentrations of MAC and BSA were conducted to find an appropriate mixing ratio for the polymer solutions leading to thermodynamically stable nanogels with the ability to encapsulate active compounds. The influence of temperature on the formation of nanogels was also studied. The consequent conformational changes were monitored using ultraviolet-visible (UV-VIS) spectrophotometry. The spectrophotometric investigations combined with diffraction light scattering (DLS) technique and zeta potential measurement results were correlated to determine the interaction mechanism and assess the self-assembling processes during nanogel formation. It was found that the hydrodynamic diameter (Dh) of the nanoparticles increased slightly at acidic pH, and the protonation of ionizable amino groups with the pH was confirmed by the zeta potential measurements. MAC/BSA nanogels also exhibited antimicrobial properties after being loaded with amoxicillin (Amox), which is an antibiotic used for the treatment of various infections. The experimental data resulting from this study provide theoretical guidance for the design and development of attractive nanocarriers for a large variety of biomedical applications.

Design and Evaluation of Carbon Nanotube Based Nanofluids for Heat Transfer Applications

2013 ◽  
Vol 1543 ◽  
pp. 143-148
Author(s):  
Sathya P. Singh ◽  
Nader Nikkam ◽  
Morteza Ghanbarpour ◽  
Muhammet S. Toprak ◽  
M. Muhammed ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Rheological Properties ◽  
Gum Arabic ◽  
Step Method ◽  
Potential Measurement ◽  
Heat Treated ◽  
Electron Microscopy Analysis ◽  
Predicted Values ◽  
The Stability ◽  
Ph Range

ABSTRACTThe present work investigates the fabrication, thermal conductivity (TC) and rheological properties of water based carbon nanotubes (CNTs) nanofluids (NFs) prepared using a two-step method. As-received (AR) CNTs heated and the effect of heat treatment was studied using X-ray diffraction and thermogravimetric analysis. The AR-CNTs and heat-treated CNTs (HT-CNTs) were dispersed with varying concentration of surface modifiers Gum Arabic (GA) and TritonX-100 (TX) respectively. It was found that heat treatment of CNTs effectively improved the TC and influenced rheological properties of NFs. Scanning electron microscopy analysis revealed TX modified NFs showed better dispersion ability compared to GA. Surface modification of the CNTs was confirmed by Fourier Transformation Infrared (FTIR) analysis. Zeta potential measurement showed the stability region for GA modified NFs in the pH range of 5-11, whereas pH was between 9.5-10 for TX NFs. The concentration of surface modifier plays an extensive role on both TC and rheological behavior of NFs. A maximum TC enhancement of 10% with increases in viscosity around 2% for TX based HT-CNTs NFs was measured. Finally comparison of experimental TC results with the predicted values obtained from a model demonstrated inadequacy of the predictive model for CNT NFs system.

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