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Chennai Wednesday, 11 April, 2018 - 16:19

A team of scientists from Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research-National Chemical Laboratory (CSIR-NCL) and Indian Institute of Science, Education and Research Kolkata (IISER Kolkata) have studied the formation of 2 Dimensional Covalent Organic Frameworks (COF)- organic solids bound together by covalent bonding, to understand the science behind the underlying structure.

COFs are porous and crystalline solid structures made of light, organic solids like Hydrogen, Boron, Nitrogen and Oxygen. Due to their lightweight nature, COFs are employed in engineering lightweight materials and their porous nature makes them useful in applications like gas storage. With wide ranging applications, economical and bulk synthesis of COFs is a challenge for material science. Several process like solvothermal synthesis have given rise to several variations of COFs, enriching the COF library.  However, to manufacture on a large scale, scientist have to first, understand the processes that lead to the formation of such a structure.

According to the authors “the fundamental understanding of the integral processes of 2D COF assembly, including their growth from nucleating sites and the origin of periodicity, is an intriguing chemical question that needs to be answered”

To answer this question, the scientists, in their study, came up with a “green and easy to perform” approach of COF formation using an acid-diamine (organic compound with two amino groups) mixture. Using the new approach, the scientist were able to explore the role of hydrogen bonding in improving the crystallinity and porosity of the COFs that were formed. They did this by studying the average distance of the Hydrogen atom in the amines to the Oxygen atom in the acid. Thorough crystallographic analyses of the salt molecules provided accurate measurement of the role of hydrogen bonding.

Further, the scientists used their knowledge of hydrogen bonding distance in the acid-diamine salts and the relationship between product quality and reactant-structure to synthesize highly porous and crystalline COF, which, according to the authors “are unattainable by other synthetic means”.

Section: General, Science, News Source:
Bengaluru Wednesday, 11 April, 2018 - 07:47

From guarding your house and livestock to being your best friend playing with you on the couch, dogs have come a long way in the past 33,000 years. But, there is another disturbing aspect to this saga of furry friends; Canis lupus familiaris (dog, for short) is also an ‘invasive’ species in many ecosystems! Like the Japanese kudzu vine or the infamous Lantana, dogs are a non-native introduced species that are wreaking havoc on the ecological balance of many sensitive ecosystems. Now, a study by researchers from the Ashoka Trust for Research in Ecology and the Environment explores the effect of free-ranging dogs, or strays, on their surroundings in India.

How bad are dogs really to our ecosystems, you ask? Previous studies have shown that domesticated dogs have imperilled 188 threatened species of animals and caused 11 mass extinctions, globally! “Domestic dogs have been considered as invasive mammalian predators. After cats and rodents, they are the third most damaging invasive predators”, says Ms. Chandrima Home, one of the researchers of the study, in an interview to Research Matters.

In countries like India, where the population of stray dogs are surging by the day without checks and bounds by a governing body, these dogs turn feral—a state in which they are neither truly wild not truly domesticated. “Unlike cats and rats which perhaps target smaller sized animals, feral dogs can target a larger range of prey size as predators as they can hunt in packs. Their impacts are as detrimental as cats and rats, though cats and rats have reported higher extinction for biodiversity”, adds Ms. Home referring to previous studies and their own findings.

The present study is the first ever assessment of the impact dogs have on the biodiversity in India. The researchers used a two-pronged approach to collect data for the study—an online survey and print media. They conducted an online survey where they asked the respondents to give details about any attacks on wildlife carried out by dogs. In the print media, they looked for keywords like ‘stray dog’, ‘dog attack’, ‘dogs attack wildlife’ and related terms in newspaper reports published between the 1st of January 2015 to the 30th of June 2016.

Among the 249 respondents who took the online survey, a whopping 73% said they had seen stray dogs attack wildlife. The researchers recorded 403 incidents of attacks by dogs on wildlife from the online survey, and 57 incidents from print media! They found that 80 species were under attack by dogs, including four ‘critically endangered’ species, twelve ‘endangered’ species, eight ‘vulnerable’ species and seven ‘near threatened’ species. From the survey results it would seem that no prey is too big for the dogs! They were recorded hunting sambar deer, blackbucks and on one occasion, they were chasing a leopard.

The study shows that the threat from dogs on wildlife is real and could come in the way of conservational efforts. So, what can we do to curb this conflict? Managing dog population is the key, say the researchers. The survey respondents also seem to agree on this as 87% of the respondents felt the need to control dog population near wilderness areas. The researchers opine that in order to protect local wildlife and ensure a good quality of life for dogs, carefully planned population control programs should be implemented near protected forest areas.

“When it comes to dog population management, nobody actually wants to look at one of the most important problem in India—dog ownership policies. People like to feed dogs (an easy way to show compassion) but do not want to be responsible pet owners. Also, sterilization is considered the only way to curb population. No one talks about reducing garbage or food for dogs. The general idea prevalent is that dogs are born to feed on garbage. I think the basic attitude in India needs a change”, explains Ms. Home.

Domesticated dogs are adding a new dimension to the threats many species of wildlife are already facing due to habitat loss, deforestation, encroachment, etc. Man’s best friend is turning out to be biodiversity’s biggest enemy, as this research shows.
 

Section: General, Science, Ecology, Deep-dive Source:
New Delhi Tuesday, 10 April, 2018 - 23:04

Dr. Renu Swarup, Senior Advisor and Scientist H at the Department of Biotechnology (DBT), Government of India took over as Secretary, DBT on 10th of April 2018. She takes over the role from Prof. Ashutosh Sharma, Secretary, Department of Science and Technology, who served as the interim Secretary, DBT. Dr. Renu Swarup’s appointment which is approved by the Appointments Committee of the Cabinet was formally notified today for a period of two years or until attainment of 60 years or until further orders. 

Dr. Swarup, who holds a PhD degree in Genetics and Plant Engineering, completed her Post Doctoral studies at The John Innes Centre, Norwich, UK. Her career at DBT started in 1989 when she joined the department as a Science Manager. Currently, Dr. Swarup is also a Managing Director of Biotechnology Industry Research Assistance Council (BIRAC), a public company that promotes innovative research in biotechnology with a special focus on startups and small and medium enterprises.    

At DBT, Dr. Swarup was part of several initiatives. As a Science Manager, she worked on policy planning and implementation. She also heads the National Bioresource Development Board and is involved in development, funding and monitoring of programmes in the area of energy biosciences, bioresource development and utilisation and plant biotechnology, tissue culture and other biomass associated programmes. She was also instrumental in the formation of the first Biotechnology Vision in 2001, the National Biotechnology Development Strategy in 2007, and the second strategy in the year 2015, where she served as the Member Secretary of the Expert Committee.

Dr. Swarup has been a fervent supporter of women scientists and has been closely involved in several initiatives related to women and science. She is credited with initiating the Biotechnology Career Advancement for Women Scientists (BioCARe), a DBT scheme.  She was also a member of the task force on Women in Science, constituted by the Scientific Advisory Committee to the Prime Minister. Over the years, she has been the winner of several awards and honours including, the ‘Bio-Spectrum Person of the Year Award’ in 2012 and National Entrepreneurship Award in 2017.

Here is wishing Dr. Swarup all the best in her new leadership role. 

Section: General, Science, Society, Policy Source:
Haryana Tuesday, 10 April, 2018 - 15:53

In a first comprehensive study, researchers from the Lala Lajpat Rai University of Veterinary Sciences and Animal Sciences and G. B. Pant University of Agriculture and Technology have explored the reasons behind the prevalence of Bluetongue Virus (BTV) in the state of Haryana. BTV is responsible for causing the bluetongue disease—a non-contagious, insect-borne, viral disease caused mainly in sheep and less frequently in cattle, goats, buffalo, deer and antelopes.

The bluetongue disease spreads through a small flying insect called midge. The disease causes the animals to develop a fever, along with excess salivation, swelling and cyanosis of the tongue. Cyanosis refers to the tongue appearing blue due to a lack of oxygen reaching the tongue’s tissue.

Although the disease causes mortality in sheep, it is usually not fatal to other cattle. Nevertheless, the recovery after the disease is contracted is slow and painful. This makes it important to understand how far the disease has spread within a population of cattle in a given area, as it affects their productivity.

To check for the prevalence of the virus, the researchers collected blood samples from 408 cattle and 395 buffalo from 80 different villages in 21 different districts of Haryana. They then separated the blood serum, which was then used in c-ELISA (Enzyme Linked Immunosorbent Assay) tests—an immunological technique that indicate if the virus is present in the serum.

The researchers found that the virus was present in 75.49% of the samples in cattle and 92.91% of the buffalo samples. In districts like Gurgaon and Rohtak, the virus was found in each of the cattle and buffalo sampled. Though previous studies have shown that the occurrence of the infection in cattle increases with the arrival of the monsoon, the researchers attribute the high prevalence in the state of Haryana to two main factors. First is the free movement of animals from neighbouring states for grazing, and the second being the increase in the number of adult midges (Culicoides oxystoma) during the monsoon.

The study provides some important data points that could help in containing the spread of the disease, against which there is no vaccine yet. Continuous monitoring of blood samples among cattle needs to be carried out to prevent future outbreaks, say the researchers. “Recent developments of inactivated or subunit vaccines may in the future help to control the disease in the state”, they add.
 

Section: General, Science, Health, News Source: Link
Kharagpur Tuesday, 10 April, 2018 - 07:39

Researchers from National Institute of Technology, Durgapur and Indian Institute of Technology Kharagpur in West Bengal, with support from Department of Biotechnology, Government of India,have shown that the one way to efficiently deal with oil sludge, is to cultivate suitable microbes using nutrients, which then disintegrate the contaminants in the sludge.

Our world today is powered by fossil fuels, the source of which is the crude oil pumped out of the ground. India, which imports all its oil, alone imported around 4.5 Billion gallons per day of crude oil last year. Once petrol and other fuels like diesel, kerosene are removed, the remaining sludge is still ripe with chemicals like hexane, benzene, fluorine and naphthalene. Petroleum Industries worldwide generate about a billion ton of petroleum sludge each year. If left untreated, the sludge could cause severe environmental hazards, like pollution and poisoning of ecosystems.

Some microorganisms like Bacillus, Coprothermobacter, Rhodobacter, Pseudomonas, Achromobacter etc are known to degrade hydrocarbons. Bioremediation involves employing such microorganisms to degrade hydrocarbons in our petroleum sludge. The researchers suggest two ways of achieving efficiency with bio remediation: biostimulation and bioaugmentation.

Biostimulation involves stimulating the bacteria by suitably altering the environment in which they grow. In this case, the researchers used nutrients like nitrates, phosphates, or a mixture of the two to stimulate the growth of microorganisms which then degrades the waste sludge. However this process depends on the ability of the native and endemic microorganisms to degrade the sludge quickly, which often isn’t the case.

To aid the native microorganisms, the researchers suggest using bioaugmentation- a process of introducing other microorganisms that can do the job faster. The petroleum sludge can be home to millions of colonies of bacteria and other microorganisms. Of these, to successfully degrade the contaminants, fermentative, hydrocarbon degrading, sulfate-reducing, CO2-assimilating and methanogenic (methane producing) microorganisms are required. Although native microorganism already present in the sludge can have these properties, to accelerate the degradation, biosurfactant producing and hydrocarbon utilizing indigenous Bacillus strains were introduced along with the native organisms.

The study showed a 46-55% higher rate of degradation was observed with the addition of nutrients or after biostimulation and and 57-75% reduction of contaminants with the addition of the bacillus strains. The researchers believe “nutrients induced community dynamics and metabolic interplay” could be the reasons for the accelerated bioremediation. According to the researchers, “This study recommends the addition of nutrients along with potential endogenous hydrocarbon degraders in the sludge for the bioremediation of otherwise recalcitrant petroleum refinery waste”

Section: General, Science, News Source: Link
Mumbai Monday, 9 April, 2018 - 15:32

Researchers from Indian Institute of Technology Bombay, Mumbai have observed a new phenomenon in a semiconductor quantum dot-- particles of nanometre (a billionth of a meter) size which are also called artificial atoms) made of Cu2ZnSnS4  (CZTS). By shining Ultra Violet (UV) light, on the quantum dots immersed in an electrolyte, they noticed an increase in its capacitance. The effect could be engineered to serve as photocapacitors- capacitors that are charged using light.

A capacitor can be thought of as a tiny battery. It can store charges between two plates of metals, which then discharge to provide a burst of electricity. It is then charged again, using a source of electricity, just like batteries. A Photocapacitor, much the same way stores charges, when shone with light, which can then discharge to provide a small charge.

When particles or objects are immersed in a fluid, especially an electrolyte- an electrically conducting solution, double layers of separate positive and negative ions are formed on the surface of the immersed object. In the case of CZTS quantum dots too, when immersed in an electrolyte, such a charge separation and double layer formation was observed. But when the CZTS particles were bombarded with UV radiation, the researchers observed a 26% increase in integral capacitance of the particle, meaning it could now hold more separated ions on its surface than before. This in turn leads to a higher flow of current.

The researchers believe that the increased charge separation occurs due to additional carriers like electrons or positive ions that are generated by excitation due to the UV light, which leads to larger electrostatic forces between the quantum dots and the electrolyte it is immersed in. This in turn leads to an enhanced double layer, and hence a higher capacitance. Their theory was supported by another observation- a decrease in the differential capacitance which according to the researchers could be happening due to an enhanced double layer.

The researchers claim “This (study and results) illustrates the utility of a colloidal quantum dot-electrolyte interface as a non-linear photocapacitor”

Section: General, Science, Engineering, News Source: Link
Mumbai Monday, 9 April, 2018 - 08:17

Scientists from IITB show how using drugs in combination can help treating tuberculosis caused by drug resistant bacteria.

The fact that Mycobacterium tuberculosis, the bacterium that causes the deadly tuberculosis, has developed resistance to most of the antibiotics we have today, is not news anymore. Many bacteria are developing resistance to common antibiotics faster than the number of effective drugs being discovered to fight them. The need of the hour is not just a “new” drug, but possibly a new method of treatment that can fight drug resistant bacteria. Now, a study by Prof. Sarika Mehra  and her team from Indian Institute of Technology Bombay (IITB) has uncovered a mechanism to increase the efficacy of the commonly used antibiotic rifampicin.

But, how did these bacteria become resistant to the same drug that once killed them? Our irregular and improper use of antibiotics is to be blamed. Due to intermittent exposure to these drugs without completion of an antibiotic course, many bacteria have evolved mechanisms to survive in the presence of these antibiotics. Now, they have turned fatal; multi-drug resistant tuberculosis was responsible for 2,50,000 deaths worldwide and 4,80,00 new cases of tuberculosis in 2015 alone!

In this study, published in the journal Frontiers in Microbiology, the scientists have improved the efficacy of rifampicin by delivering it with another active compound called cumene hydroperoxide (CHP). “The current regime against tuberculosis involves combination therapy of drugs, which works fine in eradicating drug-sensitive Mycobacteria. However, many of the existing drugs are ineffective against the widespread drug-resistant strains of Mycobacterium”, says Prof. Mehra, who headed the study. “A major focus of our research is to find alternate ways of targeting resistant bacteria by use of an adjuvant---a compound that by itself might not have antibiotic properties, but can enhance the efficacy of existing anti-TB drugs”, she adds.

The researchers used cumene hydroperoxide, an oxidizing agent, as it induces ‘oxidative stress’ in the bacterial cell. Oxidative stress is the disruption of the balance between free radicals (atoms with unpaired electrons) and antioxidants that neutralise them. “Under oxidative stress, many free radicals are generated and they can attack the various constituents of the cell such as the DNA.”, explains Prof. Mehra.

To save themselves from oxidative stress, the bacteria destroy these harmful free radicals by converting them to their non-radical form using enzymes. However, if the volume of radicals is much more than what can be neutralized by the cell’s enzymes, the radicals start attacking the components of the bacterial cell itself. The researchers have exploited this mechanism by increasing the production of free radicals using cumene hydroperoxide, which targets the cell membrane, leading the cell to rupture and death.

The researchers tested their combination of drugs on Mycobacterium smegmatis and Mycobacterium bovis BCG, close cousins of the TB bacteria. They subjected these bacteria to various combinations of the antibiotic rifampicin, and the oxidising agent cumene hydroperoxide, in different doses. They found that if used in combination with cumene hydroperoxide, the Rifampicin dose required was 16 times less than an individual dose of the antibiotic. Individually, a minimum dosage of 32 microgram(μg)/ml (equivalent to a pinch in a bucketful of liquid) of rifampicin, or 380 μg/ml of cumene hydroperoxide, was required to inhibit bacterial growth. But, when given in combination, minute amounts of rifampicin and a lesser than half the dose of cumene hydroperoxide, had the same effect. Further, a drug-resistant strain that needed high dose of rifampicin for growth inhibition, could now be inhibited by a lower dose of rifampicin in combination with of cumene hydroperoxide.

So, how did the combination of drugs act on the bacteria? In most cases, treating infections with antibiotics, including rifampicin, has one major issue -- the amount of drug that the bacterial cells absorb is very less. More the drug absorbed, better is the efficacy. In this study, the researchers observed that in the presence of cumene hydroperoxide, rifampicin was readily taken in by the cells. Once inside, rifampicin prevents the production of enzymes which neutralize the free radicals. The free radicals thus produced caused oxidative stress in the bacterial cells and resulted in the death of these cells.

Using the drugs in combination enabled using smaller drug dose. This is of significance, since this reduces the risk of side effects. “The effect of radical species on healthy human cells is similar to that on bacterial cells. It may cause damage to DNA and various cell components and increase the risk of diseases such as cancer and Alzhiemer”, explains Prof. Mehra.

In the backdrop of evolving ‘superbugs’, the study definitely holds hope in countering them. “As the data obtained so far is very promising, we will next extend this to Mycobacterium tuberculosis strains in collaboration with a lab used for research on dangerous biological agents and organisms”, says Prof. Mehra on the future direction of this research.

Section: General, Science, Health, Deep-dive Source:
Nagpur Friday, 6 April, 2018 - 16:08

Scientist from Visvesvaraya National Institute of Technology, Nagpur, National Institute for Material Sciences, Ibaraki, Japan and Institute for Plasma Research, Gujarat have developed a novel composite material composed of carbon nanotubes decorated with thin films of zinc ferrite (ZnFe2O4) for practical applications like, energy storage.

Supercapacitors are devices that store a large amount of energy in an electric field between the plates of two electrical conductors. Supercapacitors are called so due to higher amounts of energy storage capacity, compared to conventional capacitors. Recently, thin film supercapacitors have gained much prominence, due to their small volume and high energy and power densities. This makes thin film supercapacitors efficient components while developing energy storage solutions.

In their recent study, the scientists built high performance supercapacitor using thin film zinc ferrite anchored on multiwalled carbon nanotubes (CNT)—where carbon molecules are arranged in a cylindrical nanostructure, much like a rolled up sheets of carbon molecules. The scientists used successive ionic layer adsorption and reaction (SILAR) method to build the thin films anchored on CNT. Here successive atomic layers of zinc ferrite are deposited on the carbon nanotube cylinders, one at a time, to form the complete structure. According to the authors “This is a simple and inexpensive method which has the advantage of direct electrode formation without the use of any binder”. This helps bring down the overall cost of manufacturing the devices, while also enabling easier scaling of the manufacturing process.

The composite electrode (ZnFe2O4-CNT) thus formed yields a high specific capacity of 217 mAh g–1 at 5 mV s–1, making it a suitable candidate for high performance supercapacitor applications. The scientists believe this high specific capacity is formed by contributions from the inner and outer active surfaces of the hybrid ZnFe2O4–CNT electrode. The device also demonstrated the highest specific energy and specific power, when compared to conventional supercapacitors.

“This clearly demonstrates that our hybrid ZnFe2O4–CNT electrode is promising and innovative for energy‐storage applications” exclaim the scientists about their latest offering.

Section: General, Science, Engineering, News Source: Link
Bengaluru Friday, 6 April, 2018 - 07:44

The Golden age of antibiotics was an era spanning from 1950 to 1960, during which most common antibiotics like Penicillin, Streptomycin, and Chloramphenicol were discovered. These antibiotics were considered to be 'silver bullets' that would soon eliminate all bacterial infections. Unfortunately, bacteria proved to be extremely resilient, and resistance to these drugs quickly emerged. Today, bacterial pathogens resistant to nearly all antibiotics threaten to undo decades of medical progress. The indiscriminate use of antibiotics for the treatment of common infections and in the food industry  have  exacerbated the problem,  giving rise to new drug-resistant pathogens worldwide. Hence, researchers from around the world are compelled to discover better antibiotics to kill some of the most potent drug-resistant bacteria. In one such attempt, researchers from the Indian Institute of Science, Bengaluru, led by Prof. Nagasuma Chandra, have used a computational approach to design and synthesise amino acid polymers called peptides, which are highly effective in killing an array of multi-drug resistant bacteria.

Hundreds of such peptides, commonly called as 'antimicrobial peptides' (AMPs), that fight against invading bacteria, are found in multicellular organisms, including humans. The researchers of this study, published in Journal of Biological Chemistry, used a machine learning algorithm that studied the sequences of thousands of such peptides.  They deciphered the common patterns unique to those peptides.  As an analogy, a meaningfully constructed sentence inherently uses a framework of rules that can be considered as its grammar.  The researchers looked for such a 'grammar' in the sequences of these antimicrobial peptides.

“Protein sequences remarkably are similar in structure to language, where complex rules about syntax and grammar help define the semantics (or meaning) of a sentence", says Deepesh Nagarajan, from the Department of Biochemistry, IISc, the first author of the study.  To reveal this hidden grammar, the researchers used a neural network-based algorithm called Long short-term memory (LSTM). “LSTMs have a kind of ‘memory’ that allows it to retain information for 1000s of time-steps, which is very useful for   tasks such as speech-recognition and language processing”, remarks   Tushar Nagarajan who wrote the algorithm.

The researchers trained their algorithm by feeding it with thousands of unique peptide sequences that were known to possess antimicrobial properties. The training helped the algorithm to analyse and learn. “We had thousands of peptide sequences to analyse, whereas, at the time of previous work, only hundreds of antimicrobial peptides were characterised”, says Deepesh, commenting on the success of the prediction. The program then predicted several thousand candidates that had potential antimicrobial activity.

A few antimicrobial peptides were synthesized and found to possess activity against a variety of common pathogens. The best peptides were found to inhibit multi-drug resistant pathogens resistant to drugs of last resort like meticillin and carbapenem antibiotics. Further, one of the peptides tested was able to decrease the bacterial load of drug-resistant Acinetobacter baumannii a hundred-fold in 4.5 hours, in a mouse model of infection.

So how did the peptides act on bacteria? "We discovered that the peptides bound to and disrupted the bacterial cell membrane" says Prof. Disphikha Chakravortty, an author of the study. Peering through an electron microscope, they saw that the cylindrical bacteria had become ridged and flattened after being treated with the peptides. The bacteria were seen bleeding out cytoplasm through the holes created by the peptide binding. Since the entire cell membrane is targeted, the researchers believe that the bacteria will never be able to develop resistance against it.

“By targeting and disrupting the entire cell membrane, we simultaneously target a variety of lipid molecules, membrane proteins, and ion channels. The pathogen has to simultaneously evolve changes in all these molecules to develop resistance, which is much more difficult to accomplish via random mutations”, says Nagasuma Chandra.

This path-breaking study succeeds at developing drugs that target the bacterial cell as a whole, rather than focus on a single molecule within the cell. Since drug-resistant bacteria are quick to evolve, any bacterium in the community with a slightly different version of the targeted molecule has the potential to survive and thrive. The peptide molecule, developed by the researchers causes irreparable damage on a scale that the bacterium cannot recuperate, let alone develop resistance!

Section: General, Science, Health, Deep-dive Source:
Kanpur Thursday, 5 April, 2018 - 16:07

Scientist from Indian Institute of Technology Kanpur (IITK) have developed a novel ternary nanocomposite (compound made of three different nano compounds) which can remove methylene blue from a solution when shone with visible or Ultra Violet (UV) light.

Methylene blue, also known as methylthioninium chloride is a well known medicinal compound that has been in use for over a century. It has been commonly used to treat urinary tract infections, cyanide poisoning and methemoglobinemia, a type of disease which increases the levels of certain type of haemoglobin in the blood. Methylene Blue is also used as a dye in procedures like chemoendoscopy to test the urinary tract for leaks and fistulas.

However, methylene blue is also known to cause severe side effects like hypertension, fever, dizziness, nausea and vomiting. When doses larger than 5 mg/kg are injected, the compound is also known to cause bladder irritation and anemia. This makes it important to remove excess of methylene blue from the body and other other sources, like drinking water.

In their new study, the scientists formulated a ternary nanocomposite based on titanium dioxide, ferric oxide and reduced graphene oxide (rGO-Fe3O4-TiO2) for degradation of methylene blue under visible or UV light. The nanocomposite, when illuminated with visible or UV light undergoes a process called separation of charge carriers, wherein electrons from TiO2 move to rGO, thus initiating another process called photo-Fenton reaction, which provides highly reactive hydroxyl ions which mineralizes the methylene blue in solution. The nanocomposite was prepared using a wet-assembly method with varying weight ratio of each of the components to arrive at a suitable weight ratio for efficient degradation of  methylene blue.

The study has revealed the rGO-Fe3O4-TiO2 nanocomposite having composition 1:1:2 has achieved maximum degradation of methylene blue from the aqueous solution. It also showed that About 99% of the dye has been removed within 6 min under UV irradiation, while in presence of visible light, 94% has been degraded from the wastewater.

According to scientists “these results indicate that these ternary nanocomposites possess great potential for both UV and visible light driven methylene blue destruction from the wastewater”.
 

Section: General, Science, Technology, News Source: Link

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