Abstract
Technological advancements are often brought up for urbanization and industrialization that portrays the diverse and dominant pollutants as the primary by-products to the ecosystem of air and water. Carbon utilization is a well-known old-age practice that is always used for remediation of the environment. In the past, many inclinations of researches witnessed the sustainable development of synthetic nanomaterials and nanocomposites particularly for energy applications and environmental remediation. Thus, the new approach of sustainable synthesis has been investigated, evaluated and analyzed for sustainable nano carbons development. Tailoring the depicted synthetic nanomaterial with polymers as the primary nanocomposite material had determined a specific new group of bio-compatible environmentally benign materials. Thus, advanced basic research is summarized in the present perspective.
Introduction
The use of chemicals such as agrochemicals, food additives, polymers and composites, fertilizers, dyes, pharmaceuticals, synthetic detergents, conventional reserves of energy, to mention but a few, increase the period across the developed and developing nations and simultaneously is very significant for the development of a country’s economy. The depicted products are being consumed by the society at an exponential rate thus, creating and generating more pollutants in terms of waste disposal, waste generation in the operation process and fuel combustion. Up to date, due to the increased consumption and operation of the reserves of conventional energy, coal, and fossil fuel are, therefore, the main factors of increasing the depicted environmental pollutions at such an alarming rate. Nevertheless, the residue of the depicted pollutants always generates unwanted carbons such as soot that when it interacts with the ecosystem, it imparts its toxic nature, thus, affecting the ecology.
Development of the environmentally benign green materials as well as its competent with the advancement in technology are essentially and have currently become a difficult task for the eco-friendly developing society in the ecosystem. The concept of waste prevention, production of zero-waste, and with the utilization of effective and efficient materials is the primary concern for industries. Thus, for a society to stay healthy, the function of green chemistry is important in attaining the depicted targets (Ando, Zhao, Sugai, & Kumar, 2004). Moreover, as the well-known green chemistry mechanism offers a reduced approach to synthesizing protein, it reduces the toxic chemical substances in the creation and designing of effective chemical products (Xiao, Ren, & Liao, 2004). In the current world and generation, due to the rare and unique characteristics of carbon-based nanomaterials such as high mechanical strength, ease in functionalization of surfaces, good electrical conductivity, and effective thermal stability of the carbon nanotubes (CNTs), carbon-based fullerenes, graphene, and carbon quantum dots, high interest is always attracted towards research and utilized vastly in numerous application purposes (Hanzawa et al., 2011).
In most reported researches, as wonder materials, synthetic nanomaterials and nanocomposites are always modified or used directly for most aforesaid applications. However, although following expensive hydrocarbons and complex techniques or other toxic sources such as laser are always challenging to handle in various routes of synthesis such as laser ablation, plasma CVD, vapor deposition (CVD), et cetera, used to synthesize various types of synthetic nanomaterials. On the other hand, some researches also depict different ways in which environmentally friendly and inexpensive approaches can be exploited to recover the synthetic nanomaterials and nanocomposites as well as showcase their applications in sensing and remediation (Lazzeri & Barreiro, 2014). Thus, nanocomposites’ synthesis plays a significant role in the currently developed application functions like biomedicine, environmental remediation, electronic parts, energy storage, to mention but a few. The depicted paper, therefore, is premised on a discussion regarding synthetic nanomaterials and nanocomposites majoring on fullerenes, carbon nanotubes and graphene with production and potential applications of the same. Also, special attention shall be paid on the environmental and energy-related sectors as well as their important roles in enhancing effectivity and efficacy.
Classification of Synthetic Nanomaterials and Nanocomposites
Nanomaterials have the tendency of polymerizing into large molecular compounds of weight with numerous long unbreakable chains because of their unique electronic construction as well as their smaller size in the group IV elements which makes it connect with other elements easily. As carbon contains four electrons in its valence layers, it can form strong covalent bonds easily with non-metals and metals (Avouris, Appenzeller, Martel, & Wind, 2003). Moreover, due to the depicted property, most compounds that are carbon-based exist in numerous molecular forms as well as similar types of atoms can be grouped in various shapes, with varying allotropes (Avouris et al., 2003). Diamond and graphite are always the two known allotropes of carbon that occur naturally in the earth's surface and can form other multiple carbon allotropes from natural sources of carbon for different functions. With the knowledge of bottom-up and top-down nanotechnology approaches, a new group of carbon nanomaterials and nanocomposites is introduced.
The various types of carbon nanomaterials have been tested experimentally and developed successfully as advance products in numerous engineering applications. Generally, the carbon nanomaterials are found between 1 and 100 nm range of sizes. Thus, the unique characteristics of carbon nanomaterials such as high thermal and mechanical stability, ionic conductivity, and good electrical at the nanoscale as opposed to other materials are competent and exceptional for numerous engineering applications (Ando et al., 2004). Nonetheless, the depicted nanomaterials are grouped further depending on the geometrical structures and shapes generating different forms of existing nanomaterials such as nano horns that are horn-shaped, carbon nanotubes (CNT) that are tube-shaped, carbon nanospheres (fullerenes) that have an ellipsoidal spherical shape, zero-dimension dots or the carbon quantum dots (CQDs) (Hanzawa et al., 2011).
Due to the perfect and efficient properties, carbon nanomaterials are always utilized extensively in synthesizing the nanocomposite materials which are in turn used in applications such as displays, conductive plastics, composites, gas storage, paints, textiles, micro/nanoelectronics microchannel, and antifouling batteries that are durable in cycling charge (Lazzeri & Barreiro, 2014). On the other hand, the quantum dots of carbon, as an emerging new biocompatible material, have surpassed the properties of fluorescence and have possessed many valuable perfect characteristics such as numerous surface functional groups, low toxicity, low cost, high aqueous solubility, and an active functionalization large surface area. Besides being used as a major biocompatible material like new quantum dots of carbon group, nanomaterial can also be used as heavy metal sensing and gas biosensors (Lazzeri & Barreiro, 2014). Specifically, CQDs' unique features such as photo-induced electron transferability and up-converted behavior of photoluminescence (PL) of the quantum dots of carbon have proposed various new ways of harvesting sunlight from the nonconventional reserves to attain effective and efficient metal-free photocatalysts.
Fullerenes
Fullerene, denoted as buckminsterfullerene (C60), is an immediate carbon allotrope between diamond and graphite as it is from the atomic bunch Cn repeating unit (n > 20) that are composed collectively to form a specific hollow-core spherical surface or an empty space region inside its molecule. The atoms of carbon are always located on the sphere’s surface at the vertices of hexagons and pentagons and connected to form sp2-hybridizing covalent bonds. C60 always has two primary bond lengths where the 6:5 double-ring bonds are longer than the 6:6 bonds (Lazzeri & Barreiro, 2014).
