Wednesday, 28 June 2017

EMPLOYMENT OPPORTUNITIES FOR CHEMICAL ENGINEERS


Some chemical engineering professionals share there insights on the opportunities available for those that specialise in the profession. These are excerpts of the insights as shared by the US chemical engineers on AIChe website.
The most interesting of them was...

Responses varied considerably, but certain themes did seem to recur.
  • A number expressed how broad-ranging the opportunities are for chemical engineers in general:
A ChE degree is still a great degree and allows for employment in a diverse range of fields and professions.
But looking at more specifics, some pointed out that while there are jobs, graduates may want to consider seeking opportunities and advantages outside traditional areas:
Chem E grads continue to be well recognized over other engineering fields as excellent candidates for positions throughout manufacturing operations that are non-engineering and non-technical.
And:
Chemical engineers are increasingly finding work in allied fields, rather than in traditional chemical engineering fields.  I do a considerable amount of mechanical engineering and have for awhile, because I work for an electric utility. I also do a considerable amount of chemical engineering, specifically water purification. I think integrating skills from several fields is increasingly necessary.
Meanwhile, when answers were more specific to an industry, it seemed clear that the past year was not easy for some. Multiple respondents expressed great concern over a downturn in oil and gas:
2016 was a tough year for the oil and gas market, and it did seem to affect the jobs in the area. Current employer was under a hiring freeze.

While some expressed an uptick in some areas for hiring among recent grads, more-experienced engineers pointed out cost-cutting—and sometime ageism—behind the new hiring, and signaled the importance of achieving a healthy work-life balance:
Companies are very cost conscious and will likely hire young to offset cost of aging workforce. Please inform the youth of the opportunity cost (e.g., work-life balance, sanity, etc.) versus success of gaining employment. 
Others saw hiring opportunities and specifically when job-seekers are flexible, such as available positions that require relocation:
Employment demand appears to be strong overall, though the specifics are changing. For example, if you change jobs you may have to change industries or geographic location to find a new position quickly or without pay reduction.
  • At the same time, some saw opportunities going overseas due to employers' expressed cost constraints of hiring domestically:
A lot of EPC work is now being moved out of the US to low cost centers, such as India. The advent of cloud computing and new software technology allows much more outsourcing than was possible even a couple of years ago. Wages are depressed and many US chemical engineers have been layed off while the largest EPC companies are expanding abroad.
SOURCE

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Sunday, 18 June 2017

METHODS OF CHARACTERIZATION OF ADSORBENTS-A REVIEW V

2.2 Electron Microscopic Methods


A microscope is any device that allows details detection that it is impossible for the human eye. The main difference between optical and electron microscopes is their resolution. In 1931, the first electron microscope was developed. Its operation was based on the classic optical microscopy, but instead of visible light as source, it uses electron beams. Electron microscopy techniques have found diverse applications in adsorbent study for real-space imaging and structural analyses (by electron diffraction techniques). Scanning Electron Microscopy and Transmission Electron Microscopy are described:

2.2.1 Transmission Electron Microscopy (TEM)

A photo of the TEM JEOL 2010 microscope in the University of Bristol.
Transmission Electron Microscopy is one of most powerful techniques in materials science, which is widely used in the characterization of adsorbent.  It has ability to examine the constitutional characteristics of the adsorbent such as shape and size, crystallinity and chemical variations at a resolution down to the nanometer scale.  With advanced design, modern TEM enables lattice defects, atoms and even their movements to be seen.
In terms of its construction, a general TEM usually consists of six basic components, as follows:
1)      Source providing illumination
2)      Electrodes
3)      An optical system
4)      A sample chamber
5)      Camera(s)
6)      Vacuum system.

 The analysis capacity of TEM has been significantly enhanced by integration of several advanced techniques into the instrument.  These techniques include spectrometers, such as energy-dispersive X-ray analysis (EDX) and electron energy loss spectroscopy (EELS).
To examine materials by TEM requires a sample that normally should be less than 3 mm in diameter with the area of interest sufficiently thin to allow electrons to penetrate it. 
Schematic diagram of a Transmission Electron Microscope 
 A photo of FESEM JEOL 6300 FEG microscope in University of Bristol.
In adsorbent study, SEM is a tool that is commonly used to analyse adsorbents’ morphology. If compared to TEM techniques, SEM has less resolution. However, SEM has good enough resolution for analysing adsorbents (up to 0.1 µm) and provides three-dimensional images.
The operating principle of a scanning electron microscope is similar to TEM, the main differences lay in how electron beams are used to hit the sample and how reflected particles are converted into images. SEM operation is based on a high-energy beam of electrons ranging from 5-50 kV that impact a solid bulk, i.e. the sample. The beam runs through lenses system where it is condensed (focused); according to the principles of electronic microscopy, the smaller the beam the better resolution because the energy is concentrated in a smaller surface. Also, a coil arrangement magnetically deflect the incident beam, responsible for scanning the electrons on the specimen, line by line and point by point. In this case, the electrons that are not absorbed by the sample, but are bounced in different directions and with different characteristics as such backscattered electrons and X-rays, Auger electrons, secondary electrons among others. The image of the sample is usually generated by secondary and backscattered electrons, meanwhile, the X-rays are used for elemental identification.
These bounced particles, produce different type of signals due to their different nature and properties like density and chemical identity. Finally, signals are collected, amplified and transformed into visual images on a cathode ray tube, similar to that of televisions.
The requirement for samples being analyzed under electron microscopes, is that they can conduct electricity, for non-conductive materials, they are usually coated with thin films of conductive metals such as gold. The figure below shows principal constituents of SE microscope.
Diagram of main constituents of the Scanning Electron Microscope

In summary, an SEM consists of three distinct parts: an electron column; a detection system; and a viewing system.  Two electron beams are controlled simultaneously by the same scan generator: one is the incident electron beam; the other is for the cathode ray tube (CRT) screen.  The incident beam is scanned across the sample, line by line, and the signal from the resulting secondary electrons is collected, detected, amplified and used to control the intensity of the second electron beam.  Thus a map of intensity of secondary electron emission from the scanned area of the sample will be shown on the CRT screen as variations in brightness, reflecting the surface morphologies of the specimen.  Given this mechanism, the magnification of the SEM image can be adjusted simply by changing the dimensions of the area scanned on the sample surface.
 
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Thursday, 15 June 2017

Boosting the flavonoids and antioxidant activity in onions



In this research, the organic conditions for boosting the flavonoids and antioxidant of onions was unveiled. Five years ago, a highly publicized meta-analysis of more than 200 studies concluded that organic food was no more nutritious than conventionally grown food. Since then, however, additional work has suggested the organic foods contain more health-benefiting phytochemicals. Now, researchers have found that flavonoid levels and antioxidant activity in organic onions are higher than in conventional onions. Their investigation, in ACS’ Journal of Agricultural and Food Chemistry, is the longest-running study to address the issue.
The authors propose that the conflicting results from previous research on organic and conventional crops’ phytochemical content could be a function of short study periods and the exclusion of variables such as weather. To help address these factors, the researchers undertook a study from 2009 to 2014 of organic (per European Commission standards) and conventional “Red Baron” and “Hyskin” onions, which are rich in flavonoids such as quercetin. Some studies suggest that these flavonoids and others are beneficial for people with a range of health conditions.
Over the six-year study, measurements confirmed that weather could be a factor in flavonoid content, regardless of whether they were grown under organic conditions. For example, the levels of flavonols decreased in Red Baron onions from 2010, the year with the lowest temperatures, but increased in 2011 and 2014 when temperatures were higher and rainfall was down. The researchers also found that antioxidant activity was higher in both varieties of organic onions. And the flavonols in organic onions were up to 20 percent higher than in conventional ones.

SOURCE
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HYDROGEN FUEL FROM HUMID AIR

Hydrogen fuel is the lightest and simplest fuel with zero emission on combustion. It is used as a fuel in vehicles. One of the biggest hurdles to the widespread use of hydrogen fuel is making hydrogen efficiently and cleanly. Now researchers report in the journal ACS Nano a new way to do just that. They incorporated a photocatalyst in a moisture-absorbing, semiconducting paint that can produce hydrogen from water in the air when exposed to sunlight. The development could enable hydrogen fuel production in almost any location.Traditionally, hydrogen destined for industrial use has come from fossil fuels. But this approach creates carbon byproducts and other pollutants. In search of a cleaner source, researchers have turned to water as a source of hydrogen. Current methods to split water focus on its liquid form and thus require liquid electrolytes, which lead to high cost, inefficiency and other technical challenges. These drawbacks could be overcome by using water in its gas phase, but few studies have explored this strategy. So Torben Daeneke, Kourosh Kalantar-zadeh and colleagues set out to fill this void.
Using a simple, scalable method, the researchers developed a photocatalyst to generate hydrogen from water vapor using a highly porous, sulfur-rich molybdenum sulfide. The compound belongs to a class of highly conductive materials previously recognized as efficient water-splitting catalysts in liquid. Testing showed that the sulfide strongly absorbed moisture from the air. Then, combining the sulfide with titanium dioxide nanoparticles, the researchers created an ink that can be coated onto surfaces, such as glass. Films printed with the ink produced hydrogen without electrolytes or external power sources at a relatively high rate. The moisture-absorbing photocatalytic paint can be applied to any surface such as building facades, introducing the novel capability of generating hydrogen fuel just about anywhere

SOURCE




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Tuesday, 13 June 2017

METHODS OF CHARACTERIZATION OF ADSORBATES-A REVIEW IV


2.0 LITERATURE REVIEW


2.1 Fourier Transformed Infrared Spectroscopy (FT-IR)


Fourier Transform Infrared spectroscopy (FTIR) is a technique based on the vibrations of the atoms within a molecule. It becomes prominent at the beginning of 20th century and then developed due to the rapid development of technologies on computer and Fourier transform. It has many advantages such as short time of measurement, high sensitivity and resolution and broad range of measurement spectrum.

 An infrared (IR) spectrum, from which the details of the functional groups present on the adsorbent can be determined, is obtained by passing IR radiation through a sample and determining what fraction of the incident radiation is absorbed at a particular energy.  The energy at which any peak in an absorption spectrum appears corresponds to the frequency of a vibration of a part of a sample molecule.  Moreover, chemical bonds in different environments will absorb varying intensities and at varying frequencies. 

The FTIR sample handling is to grind the adsorbent finely with a specially purified salt (usually potassium bromide) to remove scattering effects from large crystals.  This powder mixture is then crushed in a mechanical die press to form a translucent pellet through which the beam of the spectrometer can pass.

Therefore IR spectroscopy involves collecting absorption information and analyzing it in the form of a spectrum.  Since each interatomic bond may vibrate in several different motions (stretching or bending), individual bonds may absorb at more than one IR frequency.  Stretching absorptions usually produce stronger peaks than bending, however the weaker bending absorptions can be useful in differentiating similar types of bonds (e.g. aromatic substitution).

The basic components of an FTIR spectrometer are shown schematically in the figure below.  The radiation emerging from the source is passed to the sample through an interferometer before reaching a detector. Amplification of the signal converts the data to a digital form by an analog-to-digital converter and then transferred to the computer for Fourier transformation to be carried out.

 

 One of the great advantages of infrared spectroscopy is that virtually any sample in nearly any state can be studied.  Liquids, solutions, pastes, powders, films, fibres, gases and surfaces can all be examined by a judicious choice of sampling technique. FTIR spectroscopy is carried out to study the potential existence of C-N, C=C and C≡N bonds among others in the adsorbent.
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Monday, 12 June 2017

Chemical engineers caution NIGERIAN GOVERNMENT on modular refineries


The deputy national president of the Nigerian Society of Chemical Engineers (NSChE), Engr. Onuchie Anyaoku; while speaking after the monthly meeting of the Federal Capital Territory (FCT) and Nasarawa chapter of the NSChE, which was also used to inspect WEAMS factory owned by a fellow of the society, Engr. Wereuche Morgan Amadi; called on the Federal Government to  be more careful on its plan to build modular refineries to avoid the challenges facing the existing ones. 
Engr. Anyaoku, who said the modular refineries were not in any sense different from big world-scale standard refineries apart from its small size, stated that the skills, the expertise and the knowledge required to build, manage and maintain modular refineries were exactly the same in big refineries.  
He said, “The environmental and safety challenges faced in big refineries are also faced in modular refineries. So, the society is not against modular construction, especially if it is done in the country, and if it is modularised such that we can export the jobs outside the country, the society is not against it.   
“But if it is modularised to be fabricated and constructed in the country and it meets the business need of the promoters without direct cash injection from government, the society is not for it.  
“In a nutshell, that is what the society has gone to present to the government, to be conscious and careful so that the government is not drawn into refining assets when everybody knows that the ones the country currently own are underperforming. If business leaders and entrepreneurs are interested in building modular refineries, government should create an enabling environment for them to do so.”  
Last Friday in Abuja, the society presented a position paper to Acting President Yemi Osinbajo on modular refineries, which the government intends to adopt as a policy. 
Engr. Anyaoku, who decried the near absence of job opportunities for young chemical engineers, said no country could develop without industrialisation, science and engineering. 
He said the meeting with the acting president was used to submit a letter of request to the Presidency for the society to be considered for inclusion and participation in the various committees and agencies of government set up to drive the energy sector growth, Nigeria’s industrial revolution, the national economic and growth master plan and the Nigeria sugar development master plan.   
Highlight of the occasion was the presentation by Engineer Chinweze Michael on the hydro-carbon processing software used in the oil and gas industry, one of the core mandates of the WEAMS factory.

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Sunday, 11 June 2017

METHODS OF CHARACTERIZATION OF ADSORBATES-A REVIEW III


1.4 Characterization of Adsorbents


Being that adsorption capacity of adsorbents depends on surface area, pore structure and surface groups, polarity, solubility and molecule size of adsorbates; solution pH and the presence of other ions in solution; they need to be characterized by various analysis techniques so as to investigate and obtain information pertaining their physical structures and chemical properties.

It was also argued that application of solid adsorbents requires their characterisation which comprises the determination of their chemical composition, crystallographic and geometrical structure, surface and mechanical properties, and the energy distribution functions as well as the shape and size distribution of the pores within the materials so as to know their energetic heterogeneity and physical nature. When associated with additional independent measurements; such as calorimetric, spectroscopic and other ones; it gives valuable details on the correlation between the energy distribution of adsorption sites and their chemical nature. Also, the main purpose of characterization of adsorbents is to establish relationships between their properties and applications. It should be emphasized that not all the techniques are suitable for all adsorbents. While characterizing adsorbent, it is important to identify what specific characteristic is intended to study in order to choose the most appropriate techniques.

Thus surface area and pore structure can be determined by applying FTIR, X-Ray Diffraction (XRD), N2 physiosorption (BET), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), electroanalytical techniques and many others to accomplish the mission.


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What you need to know about LASER.

A must read for all.


You may be wondering on how can there be a narrow light travelling a long distance without being dispersed, making use of light in surgery 'Laser Surgery'. Here is an article that will light-up your way in getting to know more about Laser light.
LASER is an acronym formed from "Light Amplification by Stimulated Emission of Radiation. Laser is a device that emits photon of light through a stimulated emission of radiation. The essential feature of laser action is positive-feedback I.e the more photons in a given frequency the more photons of that frequency will be stimulated to form [1]. This type of light a very wide applications. Lasers can be used in optical disk drives, barcode scannersDNA sequencing instruments, laser surgery and skin treatments; cutting and welding materials, laser lights displayed in entertainments among others[2].
For laser action to be achieved, there has to be an existing metastable excited state, this is an excited state with an enough long lifetime for its participation in stimulated emission. Also another requirement is the existence of greater population in the metastable state than in the lower state where the transition terminates, for then there will be a net emission of radiation.
In a nutshell, Lasers are sources of high intensity monochromatic radiation that can be applied in different fields for different purposes. 

References
[1] Atkins, P., De Paula, J., Physical Chemistry 9th ed., W.H. Freeman and Company United States 2010 pp.510
[2] Wikipedia "Laser" retrieved from https://en.m.wikipedia.org/wiki/Laser at 13:39 
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Saturday, 10 June 2017

GREENER SYNTHESIS OF ORGANIC ALCOHOLS-PHOTOCATALYTIC APPROACH



Researchers in Spain have developed photocatalytic process that offers a greener way to produce organic alcohols and other important compounds used to manufacture pharmaceuticals and pesticides.
The new technique, developed by Julio Lloret-Fillol’s team at the Institute of Chemical Research of Catalonia (ICIQ), is air tolerant, works in water, and doesn’t use the rare-earth metals often called upon to catalyse such reactions. Instead, it reduces aldehydes and ketones using a system that combines cobalt and copper. A cobalt complex plays an essential role in promoting the reaction, while a copper co-catalyst significantly increases the system’s activity. Visible light activates the process at temperatures as low as 15°C. The procedure’s tolerance to air is unusual, as oxygen normally deactivates catalysts based on earth-abundant elements.
The team demonstrated the reaction with more than 20 aryl ketone substrates, as well as a selection of both aromatic and aliphatic aldehydes. And although they tested the catalytic system in water, it showed a selectivity in favour of reducing the organic substrates over the water molecules of more than 2000:1. Surprisingly, the technique also preferentially reduces acetophenone over highly reactive aliphatic aldehydes when applied to mixtures of substrates.












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FUEL FROM CARBON(IV)OXIDE




In this discovery it has been unleashed that Earth abundant materials can be nano-engineered to make best use of increasingly abundant solar power. The sun ultimately provides the energy for almost every living organism on Earth, and could supply all of humanity’s renewable energy needs. But storing and transporting this energy is hard. Now researchers in Switzerland have developed a catalyst, made entirely from earth abundant materials, that allows solar-generated electricity to reduce the environmental pollutant carbon dioxide to the valuable chemical feedstock carbon monoxide.
One possible way to close the anthropogenic carbon cycle would be to use renewable electricity to reduce carbon dioxide – such as that produced by fossil-fuelled power stations – to liquid fuels or the ingredients needed to make them. Carbon monoxide, combined with hydrogen, can produce liquid hydrocarbons via the Fischer–Tropsch process.
Unfortunately, carbon monoxide is presently produced industrially by partial combustion of carbon rather than reduction of carbon dioxide – adding more carbon to the atmosphere: ‘We know that, in future, there’s going to be more renewable electricity coming on the grid,’ explains Wilson Smith of Delft University of Technology in the Netherlands. ‘How we use it to transform abundant chemicals like water and carbon dioxide into valuable chemicals is, I believe, going to be one of the pillars of our future energy economy.’
Copper oxide is moderately effective at electrochemically reducing carbon dioxide, producing a mixture of carbon monoxide, hydrogen, formic acid and up to 15 minor products. However, Jingshan Luo of the Swiss Federal Institute of Technology in Lausanne says: ‘It’s very challenging to separate so many products.’ More selective catalysts have usually relied on precious metals such as silver, gold or palladium.




Nano-enhancement
In the new research, Luo and colleagues used atomic layer deposition – a modified form of chemical vapour deposition allowing deposition of single, continuous atomic layers – to cover copper oxide nanowires with a very thin layer of tin oxide. This helps the nanowires to catalyse the reduction of carbon dioxide to carbon monoxide, while inhibiting any further reduction. When uncoated copper oxide nanowires were used as a carbon dioxide reducing catalyst, their selectivity for carbon monoxide peaked at 36%. However, the selectivity of the tin oxide-coated nanowires peaked at 97% and remained high across a broad range of electric potentials – important for a viable industrial solar-to-fuels setup as variable light levels would lead to variable solar cell voltages.
The material can catalyse not only the reduction of carbon dioxide at the cathode, but also oxygen evolution at the anode. However, it catalyses carbon dioxide reduction best at near-neutral pH, but needs alkaline conditions to catalyse oxygen evolution. The researchers created a two-compartment cell, with the cathode compartment at pH 6.75 and the anode compartment at pH 13. If the two compartments were completely separate, proton consumption would increase the pH of the cathode compartment, while hydroxide consumption would reduce the pH of the anode compartment. The researchers therefore placed a bipolar membrane, comprising a cation-exchange membrane and an anion-exchange membrane, between the two compartments – a technique recently pioneered by Smith’s Delft University group and others.
‘Because of the potential across this membrane, water molecules dissociate inside the membrane into protons and hydroxide ions,’ explains Luo. ‘The protons go through the cation exchange membrane into the cathode compartment, and the hydroxide ions go through the anion-exchange membrane into the anode compartment. Thus the overall pH difference of the compartments can be maintained.’ The researchers connected the cell to a triple-junction photovoltaic cell of their own design, allowing the carbon dioxide reduction process to be driven by solar-intensity light. They are now working to increase the catalyst’s efficiency and thereby reduce the over-potential (the voltage experimentally required above that thermodynamically necessary), in the hope of allowing cheaper double perovskite cells to drive the reaction.
‘It’s a nice paper,’ says Smith. ‘It isn’t the first solar driven bipolar membrane; it isn’t the first bipolar membrane carbon dioxide reduction – but it’s good for us to be looking at these systems.’ He says the nickel–iron catalysts presently used for the oxygen evolution reaction in industry are effectively beyond improvement. ‘The focus should be on the carbon dioxide reduction,’ he says. ‘They’ve a really nice selectivity: they need to keep that selectivity for a couple of hundred hours [in the paper, the researchers test the device for just five hours] and bring down the over-potential.’




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Friday, 9 June 2017

SYNTHESIS OF MELANIN-like MATERIALS



Scientists have long known that colour pigment -melanin has numerous useful qualities, including providing protection from cancer-causing UV radiation and free radicals, but also electronic conductance, adhesiveness and the capacity to store energy.
To take advantage of these qualities, scientists across the City University of New York (CUNY) have developed a new approach for producing materials that not only mimic the properties of melanin, but also provide unprecedented control over expressing specific properties of the biopolymer, according to a paper published in the journal Science. The discovery could enable the development of cosmetic and biomedical products.
Unlike other biopolymers, such as DNA and proteins, where a direct link exists between the polymers' ordered structures and their properties, melanin is inherently disordered, so directly relating structure to function is not possible. As a result, researchers have been unable to fully exploit melanin's properties because the laboratory-based synthesis of melanin has been thwarted by the difficulty of engineering its disorderly molecular structure.
"We took advantage of simple versions of proteins -- tripeptides, consisting of just three amino acids -- to produce a range of molecular architectures with precisely controlled levels of order and disorder," said lead researcher Rein V. Ulijn, director of the Nanoscience Initiative at the Advanced Science Research Center (ASRC) at the Graduate Center, CUNY. "We were amazed to see that, upon oxidation of these peptide structures, polymeric pigments with a range of colors -- from light beige to deep brown- were formed."
Subsequent, in-depth characterization of the approach demonstrated that further properties, such as UV absorbance and nanoscale morphology of the melanin-like materials, could also be systematically controlled by the amino acid sequence of the tripeptide.
"We found that the key to achieving polymers with controlled disorder is to start from systems that have variable order built in," said Ayala Lampel, a postdoctoral ASRC researcher and the paper's first author. "First, we figured out how the amino acid sequence of a set of tripeptides gives rise to differently ordered architectures. Next, we leveraged these ordered structures as templates for catalytic oxidation to form peptide pigments with a range of properties."
The findings published in Science build on previous research conducted by Ulijn, who is also the Albert Einstein Professor of Chemistry at Hunter College and a member of the biochemistry and chemistry doctoral faculty at the Graduate Center. His lab will now turn its attention to further clarifying the chemical structures that form and expanding the resulting functionalities and properties of the various melanin-like materials they produce. The researchers are also pursuing commercialization of this new technology, which includes near-term possibilities in cosmetics and biomedicine.
Christopher J. Bettinger, a Carnegie Mellon University researcher who specializes in melanin applications in energy storage, collaborated with the ASRC team on the current work. Among the materials discovered, he found that two-dimensional, sheet-like polymers show significant charge-storage capacity. "Expanding the compositional parameters of these peptides could substantially increase the utility of the resulting pigments, and this research can also help us better understand the structural property and functions of natural melanins," Bettinger said.




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Thursday, 8 June 2017

METHODS OF CHARACTERIZATION OF ADSORBENTS-A REVIEW II


1.1                Adsorption

Adsorption is a process in which a substance (adsorbate), in gas or liquid phase, accumulates on a solid surface. It is a simple and low cost system for the extraction of heavy metals and other charged particles from solution. In a more chemical language, it is the extraction of matter from one phase and concentrating/accumulating it on the surface of a second phase. It is also referred to as interface accumulation.

1.3 Adsorbent

An adsorbent is a solid material on whose surface adsorbate molecules accumulate during the process of adsorption. Adsorption of the adsorbate on the adsorbent is governed by physical and chemical interactions between the adsorbate and the adsorbent surface which depend on the characteristics (surface area, pore size distribution, and surface chemistry) of the adsorbent, and the characteristics (molecular weight and size, functional groups, polarity, solubility) of the adsorbate, and the physical and chemical properties of the solution (pH, temperature, presence of competitive solutes, ionic strength). Adsorption of an adsorbate to the surface of an adsorbent is governed by bonding forces resulting from electromagnetic interactions of the adsorbate atoms, molecules and ions, and the adsorbent surface. The most important physical properties of adsorbent, which determines its usage, as the pore structure and the specific surface area.

Adsorbent pores
The total number of pores, their shape and size determine the adsorption capacity and even the dynamic adsorption rate of the adsorbent. 

Adsorbent specific surface area
The total surface area of adsorbent quantifies adsorption sites for molecules to attach. The micropores usually provide the largest proportion of the internal surface of the adsorbent and contribute to most of the total pore volume. Mesopores, macropores and the nonporous surface of sample represent the external surface. Despite most of the adsorption takes place in the micropores, the meso- and macropores serve as passage for the adsorbate to reach micropores. Moreover, the multilayer adsorption only takes place in meso- and macropores.
 Adsorbents are classified into two types i.e. natural materials and synthetic ones. Natural adsorbents, are usually non-conventional low cost adsorbents used for removal of compounds but their adsorption capacity is relatively low. They include peat/sphagnum moss peat), red mud, coir pith, leaves, activated sludge, waste organic peel, tree fern, lignite, sawdust, banana pith, peanut hull, modified chitosan beads, natural biopolymers, biosorption materials, and minerals such as activated ash/clay.
On the other hand, there are many types of synthetic or artificial adsorbents (convential adsorbents) such as adsorbent (AC), resin, adsorbent, and so on used in adsorption operation. They are widely used adsorbents for removal of inorganic and organic compounds because they have excellent capacities for adsorption of compounds derived from their huge surface area, developed pore texture, as well as easy availability.
Adsorbents can also be classified into three as follows: 
1.      Oxygen-containing compounds: These are hydrophilic and polar e.g. silica gel and zeolite,
2.      Carbon-based compounds: These are polar or non-polar e.g. activated carbon  and

3.      Polymer–based compounds: These are polar or non-polar functional groups in a porous polymer matrix  e.g. ion exchange resins
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ACS: INFECTIOUS DISEASES DRUGS DISCOVERY



For people living in the developed world, tuberculosis (TB), malaria, and other deadly diseases not currently wreaking havoc on their health may seem like remnants of a bygone era, stamped out by progress in medicine and hygiene. But they aren’t, says Félix Calderón, Drug Discovery Manager at GlaxoSmithKline, Tres Cantos, Madrid, Spain. In developing countries – particularly those in tropical regions – the world’s poorest people continue to suffer and die from these killers.
TB remains one of the top 10 causes of death worldwide, according to the World Health Organization (WHO), and more than 95% of TB deaths occur in low- and middle-income countries. In 2015, 91 countries and areas had ongoing malaria transmission, but 90% of malaria cases and 92% of malaria deaths occurred in Sub-Saharan Africa, says the WHO.
Also affecting the world’s poorest people are 18 infectious diseases the WHO calls Neglected Tropical Diseases (NTD):
  • Buruli ulcer
  • Chagas disease
  • Chikungunya
  • Dengue
  • Dracunculiasis (guinea-worm disease)
  • Echinococcosis
  • Foodborne trematodiases
  • Human African trypanosomiasis (sleeping sickness)
  • Leishmaniasis
  • Leprosy (Hansen’s disease)
  • Lymphatic filariasis
  • Onchocerciasis (river blindness)
  • Rabies
  • Schistosomiasis
  • Soil-transmitted helminthiases
  • Taeniasis/Cysticercosis
  • Trachoma
  • Yaws (Endemic treponematoses)
Diarrheal diseases caused by pathogens and merging viruses are a concern, too, as recent etiology studies and outbreaks of Zika and Ebola have demonstrated, Calderón says.

2nd Symposium on Medicinal Chemistry for Global Health

Researching these types of diseases not only benefits the countries where they’re most commonly found, Calderón says. Changes in demographics increased travel, and climate change have made these diseases a serious global health issue.
To work toward solutions, the Royal Society of Chemistry (RSC) and the Society of Chemistry and Industry (SCI) are hosting the 2nd Symposium on Medicinal Chemistry for Global Health, June 18-20 at GlaxoSmithKline in Tres Cantos, Madrid, Spain.
The organizers’ goal is to create a forum for discussion among scientist working in the field with a focus on medicinal chemistry approaches to developing new medicines for diseases that affect global health, Calderón says. Presenters will share their latest advances in the development of new therapeutics, platforms, and collaborative models against diseases of the developing world.

ACS Infectious Diseases Special Issue “Drug Discovery for Global Health”

To celebrate the symposium and further its goals, ACS Infectious Diseases is planning a special issue on drug discovery efforts targeting infectious diseases that affect the developing world with Calderón as Guest Editor. He and Editor-in-Chief Courtney C. Aldrich encourage scientists and organizations working in the field submit a research article or perspective on this topic by November 1, 2017.
ACS Infectious Diseases is a great forum for this special issue because it’s the only journal to highlight chemistry and its role in the multidisciplinary and collaborative field of infectious disease research,” Aldrich says. “Our focus is on mechanistic and resistance studies of novel antimicrobial agents.
“I personally study TB because it is the leading cause of infectious disease mortality by a single pathogen and there has been a dearth of drug development by industry,” Aldrich says. “It is a great way to make a useful impact on global health, and it helps with my teaching responsibilities on infectious diseases in the University of Minnesota College of Pharmacy.”
“In addition to bringing in quality original material, I hope this special issue will give an overview of the status-quo of the field by including quality reviews, perspectives, and viewpoints of leaders in research labs and funding agencies, as well as explore business models for conducting this research,” Calderón says.
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AICHE: PARIS CLIMATE AGREEMENT




The American Institute of Chemical Engineers also talked on the US plan to stay out of the Paris Climate Agreement. According to AIChE,, its member engineers and their companies have supported US participation in the Paris Agreement, from which the US is now withdrawing. The agreement is an internationally negotiated plan for mitigation, adaptation, and finance of greenhouse-gas emissions that is intended to start formally in the year 2020.
AIChE’s existing climate-change policy reflects the assertion that its members are especially well suited to shape and inform technical and societal decisions about climate-change mitigation and adaptation, including those that support past US commitments pursuant to the Paris Agreement.
This statement remains true whether or not the US remains a party to the Agreement. Accordingly, in March AIChE and its Public Affairs & Information Committee (PAIC) started a targeted communication plan to engage members regarding climate change and to assist in reviewing AIChE’s climate-change policy.

SOURCE

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Tuesday, 6 June 2017

Medicinal Chemistry School




The RSC Medicinal Chemistry Residential School is the longest running and most highly valued short course for medicinal chemists in the world. For over 33 years, it has been a starting point for thousands of medicinal chemists, including some of our industry’s leading lights.
The course is designed to ease their transition from an often pure synthetic chemistry training into fully fledged medicinal chemists, who can integrate information from biology, drug metabolism, toxicology and pharmaceutical properties into design hypotheses that can lead to candidate drugs.  
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METHODS OF CHARACTERIZATION OF ADSORBENTS - A REVIEW I



1.1 Introduction

The study of adsorption of various substances onto adsorbents has been explored by many researchers, ranging from the adsorption of heavy metals, dyes and colourants to other chemicals that are involved in various processes.
Adsorption of materials (adsorbates) from gas or aqueous phase onto solid surface is a classic field of interest to chemists. This arises due to two main reasons. The first is the environmental impact of some of the adsorbates –as such they need to be removed from the environment (effluents) to avoid contamination and intoxication; while the second reason is for isolation.
The solid surfaces on which the adsorption takes place have some characteristics that make them capable of holding the adsorbate. This include their surface area and morphology, pore structure, pore size distribution, pore volume, pH, elemental composition, functional groups, surface charge, crystal structure and, of course, thermal stability.
The possible adsorption capacity of various adsorbents can be predicted by evaluating the above properties. This can be achieved by characterizing the adsorbents using the methods of characterization available. Generally, this work study the methods of characterization of adsorbents which include FTIR, electron microscopic techniques, X-ray techniques, thermogravimetric analysis and differential scanning calorimetry, BET surface area, Boehm titration and potentiometric titration.
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