A New Generation Material Graphene: Applications in Water Technology

The extreme burden of the mankind on the earth is instigating variety of environmental changes worldwide, which in turn directly affects the safe and protected water for the lives in the world. In this chapter, we focused on the main groups of the marine contaminants, their effects on mankind and methodologies to diminish the pollution of the ground and drinking water resources. The pollution caused by the heavy metal and metalloids is also highlighted as they pose a severe threat to all life forms in the environment owing to its lethal effects. Some aspects of waterborne diseases and the basic requirements for the enriched sanitation in developing countries are also discussed. The chapter also reports the current scientific improvements to deal with the variety of pollutants. This chapter will therefore help the readers to understand the issues and challenges that the human kind is facing in dealing with water quality issues.

Water is not only the most essential source of our day-to-day life, but the development of this natural resource also plays a crucial role in economic and social development processes. Waste disposal has become a worldwide problem for increased environmental awareness, for more rigorous environmental standards and dewatering challenges. Therefore, water quality management is a great work controlled by monitoring of discharge and various effluents. World health organization has issued guidelines for drinking water quality, its contaminants and how to handle water supplies in small rural communities. Qualitative and quantitative measurements are needed from time to time to constantly monitor the quality of water from the various sources of supply. This chapter highlights different water quality assessments, several sources of water pollutions and the methods used for treating water for various purposes such as for drinking, industrial water supply, irrigation, water recreation or many other uses.

With frequent oil spill incidents and industrial discharge of organic solvents, the development of highly efficient and environment friendly absorbents with both hydrophobic and oleophilic properties have become a top priority. Attributing to exceptionally large specific surface area, intrinsic hydrophobicity, outstanding electrochemical stability and superior mechanical properties, two-dimensional (2D) graphene holds significant promise as advanced absorbents for oil spill response and restoration. However, just as any other carbon allotrope, graphene as a bulk material tends to form irretrievable agglomerates due to strong π–π interactions between the individual graphene sheets. This leads to incompetent utilization of isolated graphene layers for environmental remediation applications. In order to overcome this restacking issue, the integration of 2D graphene macromolecule sheets into 3D macrostructures, and ultimately into a functional system, has materialized as a progressively critical approach in recent years. Consequentially, a wide array of exotic 3D graphene-based macroscopic assemblies (GMAs), such as aerogels, hydrogels, sponges, foams, etc., have been intensively developed during the past five years. Owing to their well-defined and physically interconnected porous networks, these rationally designed macroscopic graphene architectures can support rapid mass transfer in 3D and provide adequate accessible surfaces for molecular absorption, thereby outspreading their application potential. This chapter aims at collating the current state-of-the-art on the development and application of 3D GMAs for ultrafast and recyclable oils and organic solvents absorption. Furthermore, it distinguishes the fundamental knowledge gaps in the domain, and lays out novel strategic research guidelines, all of which will promote further progress in this rapidly evolving cross-disciplinary field of current global interest.

The widespread of organic and inorganic pollutants in wastewater from various industries, are responsible for serious environmental problems meanwhile represent a danger for human being. Therefore, the search of cost-effective methods of wastewater treatment containing in particular heavy metals and dyes, become of great importance. Noteworthy, adsorption has proven to be most effective technology for purification of wastewater from organic and inorganic pollutants. In this review, different types of green and ecofriendly materials (biosorbents, graphene-based composites, metal oxides, etc.) for dyes and heavy metals adsorption will be discussed. The biosorbents such as agricultural waste materials (waste seeds, orange peel, exhausted coffee ground powder, wood apple shell, sweet potato peels, wheat straws, etc.), activated carbon prepared from different types of agricultural waste (coconut husk, forest and wood-processing residues, papaya seeds, magnetic biochar etc.), graphene-based adsorbents and their derivatives, obtained by eco-friendly green synthesis, have been discussed and their adsorption activity has been described in details.

This chapter mainly focuses on the reduction of trihalomethanes (THMs) in drinking water in Puerto Rico. Three different nanostructured materials (Graphene, mordenite and multiwalled carbon nanotubes) were used to reduce the THMs formation by adsorption in specific contact time. The results showed that graphene is the best nanomaterial to reduce THMs in drinking water. Graphene can reduce THMs 80 parts per billion (ppb) in about 2 h.

The physical, chemical, biological, or radiological substance or matter in water makes it contaminant leaving no longer suitable as a drinking water as it may produce severe health risk. Two-dimensional (2D) carbon based material “Graphene” have attracted attention in a variety of research fields such as physics, material science, chemistry and engineering. Graphene with exceptional physical, chemical, mechanical and thermal properties, now has been widely investigated as next-generation adsorbents in both water and waste water treatment. The chemically modified graphene containing various functional groups, offer potential applications for water treatment due to adsorption of various inorganic pollutants and organic dyes. Also, the derivatives of graphene or graphene based materials such as graphene oxide (GO)/reduced graphene oxide (rGO)/functionalized GO are extensively used for water treatment as an adsorbent for heavy metal ions and organic contaminants. GO membranes are brilliant candidate for water treatment, such as sewage purification and desalination owing to very high mechanical strength, superior flexibility and hydrophilic property. Several past studies have been specially focused on the efficient exploitation of chemically modified GO, GO-polymer composite, GO-semiconductor composite and metal oxide nanoparticle attached with GO for contaminant removal from water. These GO based composites have shown outstanding performance for the removal of water contaminants as well as good adsorbent of various types of inorganic pollutants like cadmium, chromium, arsenic, mercury, antimony, lead, fluoride, zinc, copper etc. and organic dyes as methylene blue (MB), methyl violet (MV), methyl orange (MO), rhodamine B (RB) etc. This chapter is focused on the recent advances in water treatment using chemically modified graphenene/GO, and aims to provide insights into the developments in water contamination removal technologies based on these novel nanomaterials.

Pharmaceutical products are produced purposely for the treatment of diseases with the aim of improving human health. Despite their usefulness to human and animal health, pharmaceuticals are now being regarded as emerging environmental pollutants. This is due to their increased use and the fact that they are indiscriminately discharged into the aquatic environment from hospitals, households, industries, pharmacies, as well as leakages and leachates from municipal wastewater treatment plants and landfill sites. Moreover, the conventional methods of wastewater treatment were not designed with these emerging pollutants in mind resulting in the discharge of untreated or incomplete treated wastewater into water bodies. Pharmaceuticals in water are believed to exert deleterious effects on humans and aquatic organisms. The concern to remove these pharmaceutical wastes and their metabolites from wastewater before their final discharge into water bodies has culminated in the development of a wide variety of other treatment technologies such as adsorption, chemical oxidation, liquid extraction, biodegradation, and so on. However, because these pharmaceuticals are mostly water soluble and non-biodegradable, most of the treatment techniques are inappropriate for their effective removal. The deployment of an appropriate technique for effective degradation of pharmaceutical wastes in water has therefore become a necessary requirement. This chapter therefore provides a detailed discussion on pharmaceuticals in general, their occurrence in water and their health consequences. It also delved into the photocatalytic degradation of these chemicals in water with emphasis on the use of graphene based materials.

Catalytic ozonation is progressively becoming an attractive technique for quick mineralization of aromatic compounds in water, yet efficient and stable heterogeneous catalysts remain elusive. Graphene (G) and related materials have attracted growing interests as carbocatalysts given their superior specific surface area, facile decoration, and high adsorption capacity. They could not only function as a support for nanocatalysts but also behave as a co-catalyst for the enhancement in ozonation reaction. Some G-based catalysts have been synthesized and reported with unprecedented adsorption-ozonation synergistic effect. In this chapter, the pros and cons of the ozonation reaction catalyzed by G and their derivatives have been discussed tentatively. We focus our attention on the unique properties of G that are of relevance to catalysis, with emphasis on the adsorption, electrostatic interaction, active sites that have been proposed to be responsible for the catalytic activity. Moreover, some challenging issues of G based carbocatalysts have been proposed to be resolved for the future development in this field.

In 21st century, providing the fresh and affordable water through protects and purifying the water source from pollutants is biggest and most concern environmental challenges. Toxic element particularly arsenic in water is serious matter of threat for human from many developing countries, and long exposure of arsenic is generally associated with skin lesions and hyperkeratosis like adverse effects. Graphene oxide (GO) and its composites have attracted widespread attentions as novel adsorbents for the adsorption of various water pollutants due to their unique physicochemical characteristics. This chapter presents advances made in the synthesis of graphene oxides and their composites, and summarizes the application of these materials as a superior adsorbent for the removal of arsenic from water. The adsorption affinity in terms of contact time, pH, and temperature has been discussed. Competitive ion effect and regeneration are included within the text. Moreover, the challenges for the commercial uses are discussed.

The increasing interest in the use of ozone in drinking water treatment has led to concern over the formation of ozonation by-products. Disinfection with various hypochlorite solution results in the bromate formation which is being carcinogenic tested against laboratory animal. Looking at near future, the bromate concentration level is beyond the limit of provisional water guidelines drawn by the World Health Organization. From the analysis of low dose bromate extrapolation models at an upper 95% confidence limit risk of 1 in 10⁵ of the population, the results are life threatening. Possible control options originate from ‘design-for-purpose’ to control bromate formation or reduction scientifically. In this chapter, the potential grapheme based materials in creating next-generation and ground-breaking solutions to the water challenges of our times have been discussed. It is believed that grapheme based materials can meet water challenges in a sustainable ways.

Water plays a vital role in the universe for all the living organisms, but water quality gets affected by a lot of pollutants. Due to the rapid increase in industries, the disposal of numerous aromatic pollutants into the environment leads to different unpredicted effects on human health. The removal of aromatic pollutants from water is very essential for good health. Hence, this chapter focuses on the catalytic ozonation of aqueous aromatic pollutants using graphene/carbon nanotube (CNT) and their derivative materials. The various sources of aqueous aromatic pollutants were demonstrated. Some compatible treatment methods of aromatic pollutants in water with their merits and demerits were debated. The detail account of ozonation and catalytic ozonation using different materials were examined for the removal of toxic aromatic pollutants. In addition, graphene/CNT and their properties on catalytic ozonation process for the removal of aromatic pollutants were discussed. Graphene/CNT with their supported materials towards the application of catalytic ozonation was summarized by providing the operating conditions, degradation efficiency and mineralization of their products. The versatile graphene and CNT supported materials convert the toxic aromatic pollutants into non-toxic products.

The increase in demand for food products has forced production in agricultural sector at faster rate. Application of chemical fertilizers consisting of phosphorous, nitrates and potassium increased the yield with more negative impacts on environment. The run-off water from agriculture field with high concentration of nitrates and phosphates contaminate the water bodies such as rivers and lakes thus affecting the aquatic system and creatures. Algal growth and degradation occurs at faster rate and the microbes utilize the dissolved oxygen present in water. Lack of oxygen in water causes suffocation and death of living creatures resulting in eutrophication. Adsorption technique has been widely used to overcome these problems. Graphene nanocomposites find promising application in adsorbing and removing nitrates and phosphates from the water bodies. Graphene nanocomposites can be obtained from its derivatives such as graphene oxide, chemically and thermally reduced graphene oxides. They act as nanosorbents and are widely used owing to their properties such as biocompatibility, stability, high surface area to volume ratio, good conductivity and low-cost synthesis. It can be synthesised by solvent processing, melt processing or in situ polymerization methods. Studies reveal that graphene nanocomposites prove to be ideally potent in removing pollutants such as nitrates and phosphates.

Graphene, its composites and its modified forms have attracted the attention due to its novel structure and unique properties. They are widely employed in the treatment of organic and inorganic contaminants. One of the organic contaminants class—pesticides present in the aqueous environment is the threat to human and animal biota due to their carcinogenic effects. Graphene-based materials hold great potential in decontaminating pesticide bearing effluents such as adsorbents, photo-catalyst and membranes and are the current research trend. In this chapter, we reviewed the preparation, characterization and application of graphene-based materials in water purification. From the literature, it is known that graphene-based materials are widely used as adsorbents for pesticide removal. Therefore the optimum parameters affecting the adsorption process and a comparison of graphene-based adsorbents with other adsorbents are also discussed.

In the past decades, the high concerns are increasing about the feasible health threat caused by endocrine disrupting chemicals (EDCs), which could interfere with hormone biosynthesis, metabolism, or activity in a deviation from normal homeostatic control or reproduction. Among the numerous EDCs, bisphenol A (BPA) has strained great attention because of its wide occurrence and toxicity. Graphene oxide (GO) and carbon nanotubes (CNTs) are promising and novel carbon based materials that have high potential for fabrication of toxic detection sensors due to its high chemical stability, large specific surface area, abundant pore size distribution, ease of functionalization and feasibility of mass production. The fabricated sensors using GO and CNTs materials are very useful and primary choice for detection and removal of toxic harmful organic contaminants and toxic pollutants chemicals containing bisphenols. BPA is one such kind of toxic material is well-known as a typical endocrine disruptor which can mimic estrogen and lead to negative health effects on animals, wildlife and human beings. It has been widespread concerned in recent years for detection and removal of BPA due to its health hazard to wildlife and humans. BPA enters in our daily life food and water matrix by depolymerisation, leaching and migration from food packaging materials such as polycarbonates, polysulfone, polyacrylates and epoxy resins used in the industrial manufacture of water bottles, feeding bottles, internal coating in tin cans, microwave oven wares etc. An intensive study reveals that BPA has been also detected in wastewater, groundwater, surface water, and even drinking water. A large number of attentiveness studies have verified that BPA can cause cancerous tumors, birth defects, and other developmental disorders even at very low part-per-trillion doses. These carbon based materials also used to remove low-level environmental EDCs in micro-polluted water with the aid of an investigation about the adsorption of BPA at low levels in a very wide range. The GO and CNTs based sensor exhibited faster response, adequate storage stability, inexpensive, simple fabrication with disposability, satisfactory reproducibility and repeatability, and outstanding selectivity for the determination and removal of BPA. In this chapter we have done selective literature survey concerning the construction of sensors and biosensors based on GO and CNTs related materials for detection and removal of BPA from different kind of solutions and materials. The included literature survey article in this chapter also provides an overview of analytical performance for application in clinical, environmental, and food sciences research, and comments on future and interesting research trends in this field.

The discharge of heavy metal ions into the environment, due to extensive industrialization and inadequate waste disposal, has become a worldwide issue. Since heavy metals are not biodegradable, they accumulate in living organisms. The most common toxic metal ions in water are arsenic, lead, copper, cadmium, chromium, nickel, zinc, cobalt and manganese. Different treatment technologies such as coagulation, chemical precipitation, ion-exchange and filtration have been employed for pollutant removal from water, but adsorption is still one of the most suitable technologies for heavy metal ions removal. Recent studies show that graphene oxide, functionalized graphene oxide and their composites can efficiently remove heavy metal ions from water. This chapter reviews the application of graphene oxide nanocomposites in the removal of toxic heavy metal ions from aqueous solution.

Recently, water pollution is the serious environmental threat throughout the world. Water environment can be polluted by several ways. Amongst that, pharmaceutical industry wastewater assumes a noteworthy part, which varies colossally in flow and composition, contingent upon variables, for example, production rate, the particular preparation being completed, which activities are producing the waste water, etc. Every one of these factors imply that the contamination of the last emanating can be exceptionally various and variable after some time. In perspective of the shortage of water assets, it is important to comprehend and create methodologies for treatment of pharmaceutical wastewater as a feature of water administration. The arrival of graphene and grapheme based materials in water appears an inescapable outcome of the monstrous future utilization of these carbonaceous allotropes. From a natural designing perspective, it ought to be noticed that piece of the watery streams containing these nanomaterials will wind up in wastewater treatment plants, and there will be cooperation between the nanomaterials, other toxins in the sewage, which could influence the viability of the depuration procedure.

Developing sustainable and less-expensive technique is always challenging task in water treatment process. This chapter explores the recent development of photocatalysis technique in organic pollutant removal from the water. Particularly, advantages of graphene oxide in promoting the catalytic performance of semiconductor, metal nanoparticle and polymer based photocatalyst materials. Owing to high internal surface area and rapid electron conducting property of graphene oxide fostering as backbone scaffold for effective hetero-photocatalyst loading, and rapid photo-charge separation enables effective degradation of pollutant. This chapter summaries the recent development of graphene oxide composite (metal oxide, metal nanoparticle, metal chalcogenides, and polymers) in semiconductor photocatalysis process towards environmental remediation application.

Dyes are frequently let out into the environment along with wastewater sans necessary treatment. Fast, cost-effective, scientific and suitable elimination of dyes from wastewaters has been an important problem for researchers. Adsorption technique is a robust, well studied, widely employed and promising water treatment method. In the last decade, nanocarbon based adsorbents have gained attention in water treatment. These adsorbents are usually produced from low cost substrate and are found to be highly efficient than other adsorbents. Recently, graphene based nanomaterials are widely used as adsorbents to sorb various toxic organic contaminants from aqueous solutions. It showed high efficiency due to its chemical stability, structure, surface area and surface functional groups. So graphene are called as ‘miracle material’. Recently nanographene composites are proven to be a likely adsorbent for eliminating contaminants from the industrial effluents. In this chapter, we have presented briefly the synthesis of graphene and its other variants viz., GO, rGO and nano graphene composites. This chapter presents a small introduction to adsorption principles and adsorption isotherms. It explains the synthesis and use of nano graphene materials for the remediation of dyes. It also consolidates the recent literature available for dye adsorption using graphene materials and its mechanism.