Kulim Kht Conference Booth ICSSST 2012

KHT Booth at 4th. International on
Solid State Science and Technology Dec.2012

Kulim Kht QCMD Fatty Acid

Fatty acid collectors for phosphate flotation and their adsorption behavior
using QCM-D
J. Kou a,b, D. Tao b,⁎, G. Xub
a School of Civil and Environment Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing, 100083, PR China
b Department of Mining Engineering, University of Kentucky, Lexington, KY 40506, USA
a r t i c l e i n f o a b s t r a c t
Article history:
Received 31 July 2009
Received in revised form 5 March 2010
Accepted 11 March 2010
Available online 25 March 2010
Keywords:
Fatty acid

QCM-D

In this paper the relationship between the flotation performance of phosphate collectors and their adsorption
behavior was evaluated using a variety of techniques including the Crystal Microbalance with Dissipation
technique (QCM-D). The adsorption of the collectors on the surface of hydroxyapatite was primarily
characterized using QCM-D, which is a high sensitivity in-situ surface characterization technique. Additionally,
the collectors were evaluated via zeta potential and FTIR analyses. The flotation performance of the collectors
was evaluated using a laboratory mechanical flotation cell at different process parameters such as pH, collector
dosage, diesel dosage and flotation time. The two collectors evaluated were a commercial plant collector and a
refined tall oil fatty acid. The QCM-D data showed that the refined tall oil fatty acid adsorbed on phosphate
more readily and produced stronger hydrophobicity and better flotation performance than the plant collector.
The chemisorption and surface precipitation mechanisms of the refined tall oil fatty acid on the surface of
hydroxyapatite were demonstrated by means of zeta potential measurements and FTIR analysis.


1. Introduction
In the conventional phosphate flotation (Crago) process, a
significant amount of the silica present in the feed is floated twice,
first by fatty acid, and then by amine (Zhang et al., 1997). The Crago
process is therefore inefficient in terms of collector efficiency. The
phosphate mining industry is faced with higher fatty acid prices, lower
feed grade, and stricter environmental regulations (Sis and Chander,
2003). To meet the market demand for higher effectivity, lower cost
and better selectivity of phosphate flotation collectors, there is a need
to evaluate surface adsorption techniques that may help researchers
develop better collectors by understanding how the adsorption
behavior of materials affects their performance as flotation collectors.
In order to evaluate this relationship, a plant collector of proprietary
composition and a refined tall oil fatty acid were compared. The
refined tall oil fatty acid, referred to as GP193G75, was comprised of
47% oleic and 33% linoleic acids.1 Flotation tests were performed at
varying process parameters such as pH, collector dosage and flotation
time with phosphate ore from CF Industries' phosphate rock mine in
Hardee County, Florida. To better understand the behavior of the
collectors on an apatite surface, their adsorption on the surface of a
hydroxyapatite-coated sensor was studied using the QCM-D technique.
The adsorption and flotation characteristics of the two
collectors were then compared.
Most of the studies about the adsorption mechanism of collectors
on mineral surface were conducted based on ex-situ measurements
such as contact angle, adsorption isotherm, FTIR spectroscopy, and
zeta potential, which unfortunately cannot monitor the real-time
formation process and characteristics of adsorbed layer. QCM-D is the
second generation of QCM, which has been shown by many
investigators to be a sensitive tool for studying the behavior of protein
and surfactant adsorption in aqueous solutions, with sensitivity in the
ng/cm2 (submonolayer) region (Hook et al., 1998). It can simultaneously
determine changes in frequency and energy dissipation of a
quartz crystal at nanoscale in real-time and derives valuable in-situ
information on adsorbed mass as well as the mechanical (viscoelastic)/
structural properties of the adsorbed layer from experimentally
obtained data of energy dissipation in relation to frequency shift (Paul
et al., 2008). The purpose of this study was to investigate in-situ the
adsorption behavior of two collectors on the hydroxyapatite surface by
means of QCM-D technique and to determine whether the differences
observed may lead to differences in flotation performance.

Kulim KHT Wafer Cleanliness

Checking wafer cleanliness by measuring static contact angle.

An optical tensiometer is the instrument of choice to measure the contact angle between a drop of water and a wafer. The wafer is placed on the sample stage and a drop is dispensed from the liquid dispenser onto the wafer. The sessile drop can be observed with a high quality camera. The optical tensiometer software analyzes the drop shape and measures the contact angles.
Typically, when assessing the cleanliness of a wafer, a contact angle of zero is desired: the liquid wets completely the surface. Impurities increase the contact angle which is detected by the optical tensiometer.


Studying surface coating properties by measuring dynamic contact angle
Once your wafer surface has been treated or coated, an optical tensiometer can tell you about Surface Free Energy (SFE), adhesion and heterogeneity to name a few. In that case, a dynamic contact angle is preferred even though a static contact angle can also be used. The production of drops with advanced and receded edges involves one of two strategies. Drops can be made to have advanced edges by addition of liquid. Receded edges may be produced by allowing sufficient evaporation or by withdrawing liquid from the drop. Alternately, both advanced and receded edges are produced when the stage on which the solid is held is tilted to the point of incipient motion. Using an instrument with high speed image capture capabilities shapes of drops in motion may be analyzed.


A video of such an experiment can be seen at http://www.attension.com/contact-angle.aspx together with an explanation of the measurement technique.
The two application examples presented above demonstrate how an optical tensiometer can be used by wafer manufacturer. Optical tensiometers are useful instruments for semiconductor process control, surface modification process development and quality control.

Attension
Attension provides precision tensiometers with outstanding simplicity of use for liquid and solid surface characterization in research and industrial processes. The offering consists of optical, force, bubble and volumetric tensiometers for all needs and budgets, ranging from versatile, fully automated instruments, to more compact, manual systems. We are present in www.attension.com

Kulim KHT Krafft temperature & Cloud Point via CMC

Krafft Point Temperature
The Krafft temperature (also known as Krafft point, or critical micelle temperature) is
the minimum temperature at which surfactants begin to soluble (if the sample
concentration is below the CMC) and in some cases form micelles (if the sample
concentration is above the CMC).
Krafft point can be also regarded as the temperature at which micelles become
soluble (in the case of surfactant concentration is above the CMC value).
Below the Krafft temperature, there is no value for the critical micelle concentration
(CMC), i.e., micelles cannot form.
A surfactant with a low Krafft point is more soluble than a surfactant with a high Krafft
point.
The low Krafft point surfactant became insoluble at a concentration which was only
slightly lower than the CMC. By a slight increase in temperature the surfactant can
be further solubilized until the CMC is reached.
The Krafft temperature is a point of phase change below which the surfactant
remains in crystalline form, even in aqueous solution.
Surfactants in such a crystalline state will only solubilize if another surfactant assists
it in overcoming the forces that keep it crystallized, or if the temperature increases,
thus causing entropy to have a stronger force and encouraging the crystalline
structure to break apart.
Increasing the length of the hydrocarbon chain increases the Krafft temperature
because it improves Van der Waals forces.
Surfactants are effective at temperatures above their Krafft points.
Krafft Point Determination
The Krafft point can be estimated by measuring the temperature at which the
surfactant solution forms a clear solution (applies to all surfactant concentration
sample).
At this temperature the solubility of the surfactant becomes equal to the critical
micelle concentration. It is best determined by locating the abrupt change in slope of
a graph of the logarithm of the solubility against t or 1/T (applies to surfactant
concentration sample above CMC).


Cloud Point Temperature
Definition
• Anionics - is the temperature at which a product becomes turbid when it is
cooled under specified conditions.
• Nonionics - is the temperature at which a product becomes turbid when
heated.
Cloud points are characteristic of nonionic surfactants.
Cloud point may result in phase separation and instability.
Properties
• Anionics - The shorter the hydrophobic chain, the lower the cloud point of the
surfactant.
• Nonionics - The greater the degree of ethoxylation, the higher the cloud point.
Cloud Point Determination
Cloud points are typically measured using 1% aqueous surfactant solutions.
Anionics.
A neat surfactant sample is placed into a tube with a thermometer and then
immersed into an ice bath. The sample is cooled at a specified rate while stirred (to
provide even cooling). When the sample first begins to show slight hazing, the tube
is removed from the bath and inspected regularly. The cloud point is that
temperature at which the thermometer immersed in the sample is no longer visible
when viewed horizontally through the tube and sample.
Nonionics.
A 1% aqueous solution of a nonionic surfactant is heated at a specified rate and
monitored for haziness. The cloud point is the temperature at which the first haze is
observed.

Kulim KHT Sensors Detection

SENSORS USING LB TECHNIQUE

It is possible to immobilize sensor molecules into LB and LS deposited layers. The sensors can be fabricated from biochemical molecules where proteins, DNA or sugars are the detector molecules and are incorporated in a phospholipid monolayer. Other possibility is to have organic or inorganic dyes, nanoparticles or other functional molecules that give a desired response, and incorporate them into a coating with LB, LS or dip coating into a thin layer on an electrode or other probe. Detection method for such sensors can be electrical, optical or other depending on the sensor application.

An example of immobilized proteins used as sensors:

Immobilization of Alcohol Dehydrogenase in Phospholipid Langmuir-Blodgett Films To Detect Ethanol
Luciano Caseli, Angelo C. Perinotto, Tapani Viitala, Valtencir Zucolotto, and Osvaldo N. Oliveira, Jr.
Langmuir 2009, 25, 3057-3061
Alcohol dehydrogenase (ADH) mixed in dimyristoylphosphatidic acid (DMPA) monolayer exhibited enhanced transfer and detection ability towards ethanol compared to pure ADH layers. Studies proved that the ADH structure remained unchanged over one month in the mixed monolayer under storage conditions. A sensor array deposited on gold electrodes could detect alcohol down to 10 ppb concentration. For more details of the study please check the original publication.

Kulim Hi Tech KHT-Thin Channel Corrosion Flow Cell(TCFC)

HIGH PRESSURE, HIGH TEMPERATURE FLOW LOOP FOR THIN CHANNEL FLOW STUDIES



HIGH PRESSURE, HIGH TEMPERATURE THIN CHANNEL FLOW CELL(TCFC) SYSTEM 


Thin Channel Flow Cell (TCFC) is the latest product built by Cortest Inc and the only in the market of corrosion study. The TCFC is the high pressure, high temperature flow loop for thin channel flow studies.

THIN CHANNEL FLOW CELL

The technology facilitates a convenient and accurate system for in situ observation of a corrosion process in a single phase flow. The method is based on the flow dynamics between two parallel flat plates, and provides a mechanism to study corrosion in flowing systems. It eliminates the effect of centrifugal force encountered in the rotating cylinder electrode system, which is currently the most used method for small scale analysis of flowing systems. TCFC is ideal for the study of initiation and propagation of localized corrosion, providing an easy method to control and observe the mechanical and chemical effects on corrosion product films. It can be coupled with multiple measurement techniques such as electrical resistance, linear polarization resistance, weight loss and quartz crystal microbalance to provide in situ information of a corrosion process.

Kulim Hi-Tech KHT SPR BioNavis Phd Life Video

Kulim Hi-Tech KHT SPR BioNavis Video

Kulim Kht IMPROVED UNDERSTANDING OF LIPID MEMBRANES

IMPROVED UNDERSTANDING OF LIPID MEMBRANES THROUGH
COMBINED QCM-D AND EIS MEASUREMENTS
INTRODUCTION.

A current trend in the field of sensing is to use instruments in which several detection principles
can be combined in one experiment. Methods that provide a combination of structural and functional
information on biomolecules can provide crucial insights into the understanding of biomolecular
functions.

It is of great interest in many fields to investigate how peptide and protein
interactions change the propertiesof a lipid membrane. It iswell known that membrane damage
is fatal to cells and bacteria. Therefore,a common mechanism of toxins
is to disrupt the membrane or interfere with the transport of ions across
the membrane. Typically, antibacterial peptides incorporate into bacterial
membranes and destroy the ion gradient between the inside and the outside of the bacterium.
APPROACH AND EXPERIMENTAL SETUP
This application note reviews two examples of experiments where QCM-D
and Electrical Impedance Spectroscopy (EIS) were combined. The first
example deals with the disruption of a lipid membrane through the catalytic
action of the enzyme PLA2, found in insect and snake venom. PLA2
cleaves phospholipids into the corrsponding lysolipids and fatty acids by
catalyzing the hydrolysis of a phosphoester bond in the lipid molecule.
This cleavage disrupts the membrane.The second example demonstrates
the insertion of trans-membrane pores in a model membrane by the
addition of the peptide Gramicidin D.
The combination of QCM-D and electrochemistry is especially attractive
in these examples. The effect on the membrane can be sensitively detected
by the electrochemical method, whereas the strength of the QCM-D
method lies in its ability to characterize the membrane’s viscoelastic (soft
or rigid) properties.
RESULTS AND DISCUSSION
The formation of good quality lipid membranes was first ascertained by
both QCM-D and EIS. The formation of a lipid bilayer on the QCM-D
sensor was detected in real time by both frequency and dissipation shifts
and by single frequency impedance spectroscopy, as demonstrated in
Figure 1A. Bilayer formation follows the typical pathway via the adsoption
of a critical mass of liposomes, which eventually ruptures and forms
an extended lipid bilayer on the sur-face with the characteristic QCM-D
responses Δf = - 26 Hz and ΔD < 0.5, indicating that a layer a few nanometers
thick (typically 5 nm) and rigid (as indicated by the low ΔD) has formed
on the sensor surface. Note that bilayer formation as monitored by QCM-D
is already complete long before the impedance amplitude stabilizes. A
plausible explanation for this observation is that the fusion and rupture
of adsorbed liposomes is followed by a slower annealing process, resulting
from increased ordering of the lipid molecules in the lipid membrane

Kulim KHT Press Conference At Beginning Era

Kulim Kht Sedimentation Measurement/Training

kulim Kht Single Fiber measurements

Modified pore-flow model for pervaporation mass transport in PVDF hollow
fiber membranes for ethanol–water separation
2010
Panu Sukitpaneenit a , Tai-Shung Chung a,* , Lan Ying Jiang b
a Department of Chemical & Biomolecular Engineering, National University of Singapore, 10 Kent Ridge
Crescent 4 Engineering Drive 4, Singapore 117576, Singapore, b School of Metallurgical Science and
Engineering, Central South University, Changsha 410083, Hunan, PR China
For the first time, the mass transport phenomenon in pervaporation of the ethanol/water system via PVDF asymmetric hollow
fiber membranes has been demonstrated through the pore-flow model and a newly modified pore-flow model has been
proposed. The modified pore-flow model differs from the pore-flow model by factoring in the contribution of Knudsen flow to
vapor transport, which was ignored by the pore-flow model. The correlation of transport parameters to membrane pore size is
explored and it is found that the pore size expansion (including the change of membrane surface morphology) is strongly
dependent on the solvent in contact. The modified pore-flow model shows a better prediction for the permeate composition
than the pore-flow model and both models exhibit an excellent prediction of total permeate mass flux. The significance of
Knudsen flow contribution in vapor-phase transport as stated in the modified pore-flow model is discussed from the
experimental and theoretical aspects.
Journal of Membrane Science, Volume 362, Issues 1-2, 15 October 2010, Pages 393-406
Instrument(s) used:

Force tensiometers > Sigma 701

Kulim Surface Potential Meter

If there exists a difference in the electrostatic potential between two surfaces and these are put in movement relative to each other there will be a current flowing through an external circuit. This kind of “condensator” was used by Volta and Kelvin to study the differences in Volta potential between various metals. This “condensator” is often also called the Kelvin probe. Yamins and Zisman applied this method to study monomolecular films.1 Since then this method has widely been used for determining the surface potential of monolayers. The design of KSV SPOT is based on these main ideas. The main application area for KSV SPOT is in monolayer studies, but due to its stand-alone property it is also suitable for other areas where surface potential measurements are required.
Insoluble monolayers at the gas/liquid interface are generally characterized by measuring the surface pressure ()- area (A) isotherm. The  - A isotherm is characteristic for any given ampiphile2 or mixtures of ampihphilic molecules. Many substances show a variety of different monolayer phases.3,4 The major phases are easily recognized in the isotherm as sharply separated regimes with different compressibility. Although the measurement of  as a function of A can give valuable information about monolayers (area per molecule, collapse pressure, phase transition pressures and temperatures, mixing behavior of two or more amphiphiles etc) it may not reveal all of the desired information.
A complementary and a more sensitive way to characterize a floating monolayer is to measure the changes in the surface potential, V.5 This is possible due to the fact that an insoluble monolayer at the gas/liquid interface changes the surface potential through this interface. This change equals the Volta potential between the surface of the liquid and that of the metal probe. Normally only the changes in V due to the presence and changes in the state of the monolayer are measured. In this case the clean liquid surface is fixed to the value 0 mV, and the spread monolayer gives the obtained V. V can be used to determine the composition of the monolayer, the dissociation degree of an ionisable monolayer, the orientation and reorientation of the monolayer molecules at the interface during compression.3,5,6,7,8 By measuring V one can also reveal the interaction between the molecules in the monolayer much earlier than by measuring . The type of deposition that has occurred for LB films (X, Y or Z deposition) has also been determined by measuring the V.9

Kulim Surface Potential Meter

KSV SPOT is a small computer controlled stand alone surface potential measuring instrument. It is based on the non-contact and non-destructive vibrating plate capacitor method. KSV SPOT has a high accuracy, minimal drift and high reproducibility, which guarantee a high sensitivity and stability for the measurements.
KSV SPOT is mainly designed for monolayer measurements, but due to its stand-alone property it is also suitable for surface potential measurements over a range of solids and liquids.
KSV SPOT enables you to complement surface pressure - area data with the more sensitive surface potential data. Thus, giving you for example the following additional information about your Composition, Dissociation degree, Orientation, Interaction, Adsorption of your monolayers

Kulim SPR BioNavis