A Novel Green Synthesis of Au/TiO2 Nanocomposites

Prof. Lahiru A. Wijenayaka, Sri Lanka Institute of Nanotechnology (SLINTEC), Mahenwatte, Pitipana, Homagama, Sri Lanka and his collaboration team has reported on the interesting materials for effective environmental alternative remediation via nontoxic, low cost and eco-friendly methods dedicated to the scientific community. Here, a novel, facile, and green synthetic approach to synthesize gold nanoparticle decorated over TiO₂ (Au/TiO₂) nanocomposites for sustainable environmental development has been discussed [1].

Based on various metal oxide semiconductor (MOS) photocatalysts, titanium dioxide (TiO₂) is the most widely used, owing to its effective and excellent results in optical transmittance, high refractive index, chemical stability, concurrently being stable, nontoxic, and inexpensive [2]. They are highlighted with the following points: (i) Synthesis of the Au/TiO₂ nanocomposite, (ii) Microscopic characterization, (iii) Dye adsorption on Au/TiO₂ and (iv) Photocatalytic dye degradation on Au/TiO₂. The general changes of charge recombination time in TiO₂ has been estimated to be in the order of 10⁹ s, while the chemical reaction time shows the fast responses of recombination between photogenerated charges with any adsorbed species is 10⁸ to 10³s [3]. Hence, the photocatalytic reactivity of some species adsorbed on the surface of nanoparticle (TiO₂) catalyst. Therefore, the metal oxide is far from being a perfect and established photocatalyst regardless of its new trend and widespread applications.

Bio-comfortable and bio-compatibility of nanoscaled materials preparation may be a significant role to enhance via the utilization of biogenic synthetic pathways, the use of microorganisms or plant-based extracts [4]. Although the incorporation of Gold nanoparticles (AuNPs) to the surface of TiO₂ thus enhancing the photocatalysis part of the latter is well demonstrated, there is no past resultant accountability of sustainable green methodologies to develop such eco-friendly and innocuous nanocomposite/nanomaterials. In addition, many recent scientific and knowledgeable efforts have been focused on the preparation of novel nanosized materials with the support of the light assisted degradation of unwanted contaminants; or photocatalysis. Hence, other mechanisms are handled with effective contaminant capture and removal which can be conducted, such as surface adsorption which is facile and spontaneous, are relatively less exploited [5].

Figure 1. Schematic diagram of the green synthesis of Au/TiO₂ [1].

The preparation of AuNPs decorated TiO₂ nanocomposite using an entirely green chemical synthesis approach has been reported. AuNPs were synthesized by reducing tetrachloroauric(III) acid (HAuCl₄) onto TiO₂ particles using a green tea extract. Green tea acts here as both reducing and stabilizing agents, thus obviating the need to utilize any auxiliary chemicals during the preparation and/or the application of the catalyst.

The novel facile green synthetic methodology for the preparation of Au/TiO₂ nanocomposite using the following selective precursors were Titanium dioxide (TiO₂) (anatase), tetrachloroauric(III) acid trihydrate (HAuCl₄ 3H₂O) and the green tea extract contained a mixture of polyphenols (like catechin, epicatechin, epicatechin gallate, gallocatechin, and gallocatechin gallate, as well as caffeine, gallic acid and theophylline) [6, 7]. Based on the modern green method, the utilized conditions used for the reduction of Au³⁺ into the AuNPs were previously reported with experimental and optimized one. (i) the resultant material of AuNPs expressed with uniform size and morphology, (ii) green tea serves dual roles of a reducing and a stabilizing agent, (iii) preventing the need for any auxiliary chemical species, and (iv) under mild temperature conditions (50º C). Photocatalytic testing held with the dye degradation on Au/TiO₂ with same volumes of Au/TiO₂ nanomaterial suspension (250 ppm) and a methylene blue (MB) sample solution. The mixed samples were utilized under UV light exposure with and without nanomaterials. In contrast, for Au/TiO₂, there was no significant absorbance in the supernatant until the MB concentration reached 17 ppm. To conclude, they repeated the experiment much times for different durations of UV irradiation and bare TiO₂. Experimental evidence identified that the Au/TiO₂ show a superior adsorption capacity of 8185 mg g^-1 towards methylene blue (MB) in sample solutions, while the photocatalytic rate constants for the degradation of MB on the substrate expressed 4.2-fold improvement compared to bare TiO₂.

Scientific development of nanocomposite (Au/TiO₂) with suitable light mediated reaction scenario would be concluded in two distinct and independent pathways are namely (1) surface adsorption and (2) photocatalysis. They have insisted on these chemical reactions for the efficient removal of waste contaminants from the various samples (in aqueous) environmental situations.

AuNP decorated titania was highlighted with the enhancing nature of photocatalytic activities by facilitating efficient electron transfer reactions. They identified that a photocatalyzed chemical reaction resulted in a synergetic effect, during the removal of non eco-friendly chemicals (hazardous) from the contaminated sample waters.

Our SNB Team recommended this research article to enrich our reader’s knowledge about the novel green synthesis of gold decorated TiO₂. They improved the capacity to capture as well as degrade MB in sample solution indicates that the Au/TiO₂ nanocomposite has outstanding potential to serve in sustainable environmental remediation. The ability of Au/TiO₂ to be used in environmental remediation via enhanced nanocomposite surface adsorptions and ensuring photocatalysis was investigated using methylene blue (MB) as a model dye. Here, a clear understand of Au/TiO₂ nanocomposite developed via the possibility of facile and green route represents the atom economy, stability concept, prolonged storage, the superior adsorption capacity of 8185 mg g^-1for MB, significant potential for waste contaminant capture, and significantly enhanced photocatalytic degradation rate of MB. The overall theme says that material is suitable to support the environmental applications system.

References

M. Perera, et al., RSC Adv., 10, 29594 (2020).
Y. Zhao,et al., Mater. Lett., 61, 79 (2007).
M. Ni, et al., Renewable Sustainable Energy Rev., 11, 401 (2007).
S. Aswathy, et al., Spectrochim. Acta, Part A, 97, 1 (2012).
H. Wang, et al., Appl. Surf. Sci., 360, 840 (2016).
S. P. J. Namal Senanayake, J. Funct. Foods, 5, 1529 (2013).
M. Farahat et al., Br. Poult. Sci., 57, 714 (2016).

Blog Written By

Dr. S. Thirumurugan

National College, Tiruchirappalli

Tamil Nadu, India

Author Profile

Editors

Dr. A. S. Ganeshraja

Dr. K. Rajkumar

Dr. S. Chandrasekar

Reviewers

Dr. Y. Sasikumar

Dr. K. Vaithinathan

Comments

PROSPECTS ON PHOTOBIOREFINERY

Very recently, Prof. Dr. K. Faungnawakij and his research group have summarized a mini review report on an emerging renewable technique of Photobiorefinery . This is one of the beyond technique of Artificial Photosynthesis (AP) [1] . Despite great promises, AP technologies for solar H2 production and CO2 reduction are far uncompetitive to other promising technologies at the current stage . However, despite an enormous effort, time, and budget paid on AP-related researches throughout several decades, AP technologies have struggled to strive beyond laboratory demonstration except a very few exceptions [2] . This bitter reality makes the translation of this excellent science to practical application questionable [3] . Technoeconomic analysis shows that without achieving the aggressive technology targets, this technology will not be commercially viable. This has directed the research community towards the development of highly efficient yet expensive devices. While tremendous p...

Impact on Climate and Land Use Changes Around Ganga River

In India, Ganga is the largest river and also famous spiritual river, in meantime pollution issue in Ganga river is considered to be one of the most discussed topics on river water quality in the past decades . The river gets s everely polluted with untreated industrial and human wastes, and the river crossed around 11 states in India and provides water for about 40% of India's population, approximately 500 million people, we couldn’t find more than any other river in the world [ 1, 2 ]. Central Pollution Control Board (CPCB) has mentioned that 764 grossly polluting industries were discharging into the Ganga river, 487 industries are from the Kanpur region. Therefore, the Kanpur region was treated as the main polluted spot and immediate action should be taken for further recovery of water quality. The Kanpur region is one of the most important industrialized place in India. It is the most polluted stretch of the Ganga River, because of its excessive pollutant discharge from the i...

Electric Vehicle: Public Health and Climate Benefits

A research team led by Daniel Peters at Northwestern University has investigated that if we introducing electrifying vehicles in the streets of the United States could annually prevent hundreds-to-thousands of premature accidental deaths.This work highlights the potential of a synergistic solution to reduce CO 2 emissions by hundreds to millions of tons annually. The estimate of economic damages induced by introducing electrifying vehicles (EV) adoption is substantial. With current infrastructure, about 25% of electrifying vehicles adoption in the US can save approximately $16.8 billion annually, has been told in the study entitled"Public Health and Climate Benefits and Trade offs of U.S. Vehicle Electrification," in GeoHealth on 13 th August 2020 [1] . Vehicle electrification in the United States could prevent hundreds to thousands of premature deaths annually while reducing carbon emissions by hundreds of millions of tons. This highlights the potential of co-beneficial...

AN ACT OF FACE MASK MATERIAL USED TO PROTECT US FROM SARS-COV-2

“ In the absence of a vaccine, or effective antiviral, one of our only remaining strategies for controlling COVID-19 is to physically block the spread of SARS-CoV-2 in the community ” On 11 March 2020, the World Health Organization (WHO) declared the COVID-19 outbreak a global pandemic [1] . In the absence of a vaccine, or effective antiviral, one of our only remaining strategies for controlling COVID-19 is to physically block the spread of SARS-CoV-2 in the community. Given that COVID-19 is a respiratory illness, the most effective physical defense likely involves widespread public use of face coverings, in conjunction with other control measures [ 2 ] . Face coverings (also variously referred to as face masks, nonmedical masks, community masks or barrier masks ) function primarily in source control; capturing droplets expelled by an infected individual [3] . Figure 1. DIY masks to protect against from viruses sounds like a crazy idea. source click here In the absence of an...

RENEWABLE ENERGY'S ROLE IN ENVIRONMENTAL CLEEN-UP PROCESS

Human activity is overloading our atmosphere with carbon dioxide and other global warming emissions. These gases act like a blanket, trapping heat. The result is a web of significant and harmful impacts, from stronger, more frequent storms, to drought, sea level rise, and extinction. Most of global warming emissions come from our electricity sector. Most of those emissions come from fossil fuels like coal and natural gas . Sulfur dioxide (SO2) , which cause acid rain, comes from electricity generation. Nitrogen oxides (NOx) , which react with sunlight to create ground level ozone and smog, come from electricity generation. Ozone (O3) occurs naturally in the upper atmosphere where it is beneficial. Particulate matter is a type of air pollution more commonly referred to as soot. Carbon dioxide (CO 2 ) is a greenhouse gas that contributes to global climate change. Mercury is a highly toxic metal that is released from coal-fired power plants. In contra...

Scientific Research Focus on “To End Hunger”

According to the Food and Agriculture Organization of the United Nations (FAO UN), Hunger Report, Ending hunger is a major objective of the United Nations’ (UN) Sustainable Development Goals (SDG), hunger is the term used to define periods when populations are experiencing severe food insecurity - means that they go for entire days without eating due to lack of money, lack of access to food, or other resources [ 1 ]. Hunger is strongly interconnected with poverty, and it involves interactions among an array of social, political, demographic, and societal factors. An attention is must in the following topics to put an end card for poor hunger: Global Hunger Index (GHI). World Food Program’s 2020. Global Report on Food Crises. Smallholder-farming. Ceres2030. The two main international institutions are the International Institute for Sustainable Development (IISD) and the International Food Policy Research Institute (IFPRI) , joined forces to estimate what it would cost to ...

Novel Approach of Plastic Waste to Flash Graphene

Prof. Algozeeb and his research collaboration team have investigated an novel approach of upcycling plastic waste (PW) products to flash graphene (FG). This method relies on Flash Joule Heating (FJH) to convert PW into FG. A sequential direct current (DC) and alternating current (AC) flash is used in order to make a high-quality graphene. In this FJH process, they established without catalyst and works for PW mixtures that can make the process suitable for handling landfill PW. In 21 st century, PW pollution is considerable one among the various environmental issues. A very large fraction of PW ends up in the ocean, which leads to the formation of micro- and nanoplastics that threaten marine life, micro-organisms, useful bacteria, and humans. From the intense carbon footprint process, most of these synthesized plastics are used only once before dumping into landfills or water ways that terminate in the oceans. Hence, upcycling PW to higher value materials and chemicals is econ...

Electromagnetic Field: Non-Chemical Water Treatment Technology

An interesting review report on “A critical review of the application of electromagnetic fields for scaling control in water systems: mechanisms, characterization, and operation” was reported by Lu Lin, Wenbin Jiang, Xuesong Xu and Pei Xu published in Nature Partner Journals Clean Water published on June 2020 [1] . Water is the precious matter in the world. source U.S. General Services Administration has interested on non-chemical water treatment technologies. It has mentioned following important points: n on-chemical technology promises to increase the period between required blow-down cycles, thus reducing water consumption , minimizes associated issues of chemical storage, handling, and disposal, and may permit on-site re-use of cooling-tower “blow-down” water as “grey water” , it promises to be life cycle cost effective based solely on the reduction in chemical costs , this technology may reduce or eliminate chemical costs, it may not reduce other contractor costs ...

Electro-Organic Synthesis: Next Emerging Technique

Industrial developments, excessive energy consumption, sustainable technologies, environmental cleaning processes are major topics of political and social discourse. Current innovations are rated not only focusing on their benefit and utility but also concerning their eco-friendly approaches. The development of green technological processes is becoming more important and requires harmless energy sources. Particularly over the past decade, the severe limitations of fossil resources intensify the movement towards sustainable synthesis techniques with a strict cutback in the ecological footprint [ 1 ]. Electro-organic synthesis belongs to the synthetic organic chemistry discipline that facilities the direct use of electricity to generate valuable compounds. Hence, it is possible to transfer green aspects of sustainable energy sources to the whole production process [ 2 ]. Since the Kolbe’s discoveries of using electricity as a reagent for organic transformations over 170 years ago, ...

Innovations of Integrated Artificial Intelligence

Artificial intelligence (AI) is the study of methods to imitate intelligent human behavior. AI is widely heralded as an ongoing “revolution” transforming science and society altogether [ 1 , 2 ]. While approaches to AI such as machine learning, deep learning and artificial neural networks are reshaping data processing and analysis [ 3 ], healthcare, transportation and the production chain [ 4 ]. Figure 1. Integrated concept of artificial intelligence. AI Ethics Guidelines National and international organizations (European Commission, Organisation for Economic Co-operation and Development (OECD), UK House of Lords, Singapore Commission) have responded to these concerns by developing ad hoc expert committees on AI, often mandated to draft policy documents in various countries. In 2018 alone, companies such as Google and SAP publicly released AI guidelines and principles. The advisory council on the ethical use of AI scientific team have announced that results reveal a global co...

Search This Blog