Green Carbon Materials for Environmental Analysis: Emerging Research and Future Opportunities

Carbon nanomaterial-based aerogels have attracted noteworthy interest owing to unique features comprising high porosity, exceptionally low bulk density, high specific surface area, tunable surface functionality, extraordinary conductivity, hydrophobicity, good chemical stability, and thermal/electrical properties. The exceptional properties of carbon-based aerogels allow them to be applied in diverse utilities such as adsorbents, sensors, fuel cells, oil/water separation, supercapacitors, etc. Unlike conventional carbon aerogels which were based on non-renewable resources (fossil fuels like petroleum and coals), recently, due to environmental pollution and lack of fossil resources, the fabrication of carbon aerogels based on the green, renewable, economical, abundant, and inexhaustible, precursors is a very attractive subject and have generated extensive interest from the scientific community and industrial community. In this chapter, many kinds of green and natural materials like cellulose, chitosan, starch, alginate, and vegetable/fruits are summarized as carbon aerogel precursors for application in different fields including oil/water separation, sensors, supercapacitors, and adsorbents. This section attempts to supply an extensive vision of the production, characterizations, features, and applications of green carbon aerogels.

Utilization of plant biomass, especially lignocellulose carbon-based nanomaterials such as graphene oxide and carbon dots, has attracted attention in wastewater treatment to create a pollution-free green environment. In the last two decades, carbon dots and their derivatives have been effectively used in various fields (e.g., water treatment, sensor, paramedical, bioimaging, drug delivery, etc.) because of their high surface area, easy functionalization along with outstanding colloidal stability, excellent biocompatibility (vitro and in vivo), eco-friendly synthesis and low cost. Carbon dots have been synthesized by using chemical precursors followed via (i) the Top-down approach (electrochemical synthesis and the laser ablation methods) and (ii) the Bottom-up approach (Hydrothermal synthesis, Ultrasonic, and Microwave Pyrolysis). The use of hazardous chemicals and solvents has been severely affected by the environment, devastating the lives of fauna and flora and resulting in environmental pollution. Therefore, research has been molded to synthesize biomass-based green carbon nanotubes (carbon quantum dots). The morphology of these nanomaterials has been identified using advanced analytical techniques: UV-vis., dynamic light scattering (DLS), photoluminescence spectroscopy, X-ray diffraction (XRD), and High-resolution transmission element microscopy (HRTEM), and Fourier-transform infrared spectroscopy (FTIR). The present chapter deals with fabricating carbon nanotubes, including carbon quantum dots (CQDs), using plant biomass (lignocellulose) and green solvent. Moreover, challenges to preparing green carbon have also been discussed in deals. Based on the collected data, green material based-carbon dots will be of great commercial importance and may be a better option to replace currently used fluorescent materials to create a dust-free atmosphere.

An important sector of nanotechnology is occupied by fullerene family, which have been playing a pivotal role in various fields like electrochemical, sensor, solar cell, energy storage, and catalysts activities. In this chapter, we aim to present a panoramic overview of comprehensive methods in relation to the modification of fullerene families. Given this, the high surface area and physicochemical properties of fullerenes have drawn the attentions in the current researches owing to the fact that the surface modification of fullerenes would have a direct influence on aforementioned fields. With the benefit of hindsight, this nanomaterial could rise the non-radiative recombination in solar cells and the optical property. In biological activities, fullerenes show potential for considerably decreasing toxicity, and also, enhancing the antioxidant, antitumor, antibacterial, etc. Regarding their electronic affinity, it could be improved by modifying fullerenes with other prominent materials. Lithium batteries based on fullerene nanomaterials are capable to storage energy, and affect the super-magnetic behavior. The contents of this chapter would open up new horizons about the considerable potential of fullerenes in another aspect of science around the world.

Green carbon materials show superior properties including high chemical and physical stability, low density and large specific surface which enables them to be successfully employed as powerful nanoadsorbents towards the target compound/s in complex matrices such as environmental samples. This chapter aims to present the recent developments in the development of green carbon materials (i.e. carbon nanotubes, graphene, carbon quantum dots and fullerenes etc) for the removal of various environmental pollutants such as heavy metal ions, organic dye compounds, pharmaceutical compounds and so on.

The ubiquitous presence of hazardous metal ions in the environment poses a serious threat to ecosystems and consequently to human health given their persistent, bioaccumulative and toxic nature. With world population rapidly increasing and so the consumption rate, an increase of the levels of pollutants and particularly heavy metals in the environment, degrading both aquatic and terrestrial resources, is expectable. Monitoring of heavy metals in the environment serves as valuable information to lay down regulatory and counteracting measures. Sensor technology can contribute greatly to this purpose and become established as complementary or viable alternative to the more traditional analytical methods, since it allows facile, rapid, and in-situ procedures. Also, there is an increasing tendency on the application of new carbon (nano)materials for sensing, which are synthesized using renewable sources or byproducts as precursors or/and in the decreased use of hazardous and rare materials and energy demand. These (optical and electrochemical) green (nano)materials carbon-based sensors may contribute for sustainable development. Thus, in this study, the literature regarding sensors based on green carbon (nano)materials for analysis of heavy metals (in different environmental matrices) is revised and critically discussed.

Soil is one of the compartments of the earth and is essential for the maintenance of life on the planet. Through it, the necessary nutrients are provided for the development of plants, which in addition to producing oxygen on Earth, provide food. However, with the accelerated growth of the world population, it is necessary to manage the soil for the cultivation of crops, in addition to the intensive use of pesticides. These substances can percolate into the soil, contaminating groundwater. Another problem is the use of veterinary drugs for disease control or use as supplements in animals intended for human consumption. Such animals excrete their waste directly into the soil, containing residues of such substances. In addition to being able to infiltrate the soil, they can be carried to different parts by ditches and streams. Mining practices, in turn, consist of soil contamination by metals. Many of these metals are toxic and bioaccumulative. The dynamics of pollutants in the soil depends on their physicochemical characteristics. Many of these substances are poorly sorbed and can infiltrate into the soil, contaminating groundwater, reaching surface waters and seas. Therefore, efficient methods for detection of these compounds in soil are needed. There are different analytical techniques for detection and quantification of these compounds in complex matrices such as soil. However, such methods are expensive, require highly trained technicians, equipment maintenance is expensive, and sample preparation is labor intensive and costly. Thus, the use of Carbon-Dots (C-Dots) produced by green synthesis can be a very promising alternative, which provides very reliable results. The processes are simple and cheaper compared to specific instrumental methods. Therefore, in this chapter will be described the (1) characteristics of the soil, which allow the interaction and sorption of a certain pollutant; (2) a brief description of the main soil pollutants; (3) an approach to carbonaceous materials, specifically about Carbon-Dots and finally, (4) an approach about the detection of soil pollutants by Carbon-Dots. The information described in this chapter can help professionals in different areas such as chemistry, materials science, engineering (chemical, environmental, agricultural, etc.), agronomy, biology, physics, among others.

Nanotechnology, in association with green chemistry, has enormous potential in creating green carbon materials (GCM) based gas sensors that are sustainable and eco-friendly. Furthermore, the sensors generated by this technology can be fabricated, upgraded, and economically feasible. Technologies used to prepare green sensors are coulometry, chromatography, chemical vapor decomposition, conductometry, and electrochemical analysis. These methods are beneficial as they can be a time-efficient, economical, easy operation, and have minimal instrumentation. Furthermore, compared to chemical sensors, gas sensors, made from green carbon material, are more beneficial because of their unique nanoscale characteristics like high selectivity and sensitivity, which are limited in chemical sensors. In addition, these sensors have fast recovery time, can be operated at low temperatures, have stable performances, quick recovery time, low production cost, and, most important, are environment-friendly.

Green carbon materials (GCMs) formed the subject towards intense interest that fascinated much attention in the race to develop the next generation of portable, low-power sensors due to their unique mechanical, optical, and electrical capabilities. Green carbon materials (GCM) derived from biomass found to be thriving research field which exploring novel structures, diverse synthesis and versatile applications. This chapter’s focus is on GCMs, particularly the synthesis techniques that combine them with different kinds of nanomaterials to create nanocomposites, which then combine with additional qualities to create innovative materials and environmental applications.

The remarkable mechanical, optical, and electrochemical capabilities of green carbon-based materials have drawn considerable interest, making them excellent contenders for the forthcoming generation in environmental applications. The objective of this chapter is to focus on the syntheses and functionalization strategies of sustainable green carbon-based materials for sensing, adsorption, photocatalysis of various emerging pollutants. Recovery and recycling of the spent materials have also been covered in this chapter, along with a substantial emphasis on the reproducibility of the results. Then overviews on the challenges and way forward solutions for advancing with green carbon-based materials have been provided. It is anticipated that the chapter would open new doors towards the development of effective green carbon-based materials for environmental applications.