Functional Polymer Nanocomposites for Wastewater Treatment

Hazardous contaminating impurities/toxins, such as poisonous metal particles and colors/dyes, are a significant reason for the toxicity of water bodies. These contaminations make an unfriendly impact on sea organisms and immobilize the compounds in plant life. Subsequently, this issue should be moderated as a disturbing natural danger leading to different unsafe sicknesses in humans. Moreover, several waterborne pathogenic microorganisms likewise cause irresistible infections. Numerous techniques are reportedly established to eliminate these toxins and undesirable microorganisms. Adsorptive treatment and/or exclusion of water toxins and microbial sanitization through different nanocellulose (NC)-graphene oxide (GO) nanocomposite (NGON) materials (adsorbents) are introduced in this chapter. As per available literature, these adsorbent materials have shown extraordinary outcomes for the adsorptive exclusion of water contaminants such as poisonous metal ions and colors/dyes along with the removal of aquatic germs, insecticides, etc. Besides, they have numerous other necessities, including ease of preparation, cheap, and eco-friendly, as green composite blends are handily worked, energy-economical, and fit for multifaceted uses. This chapter also focuses on discussing the technologies embraced to fabricate the aforementioned adsorbents, their performance-based response with regards to adsorption capacity (Q). Our article also presents an ephemeral summary of adsorption working principles like isotherms, adsorption affecting parameters, the kinetics, along with the thermodynamics of the adsorption phenomenon. Furthermore, it reconnoiters the current applications, issues of consideration, related to these NGON adsorbents along with future perspectives.

This chapter briefly reviews the recent developments on polysaccharide-based hydrogel beads for water pollution remediation. The deployment of polysaccharide-based adsorbent materials in treating wastewater is challenging since they are very soluble in the aqueous medium. To date, modification of natural polysaccharides has attracted extensive attention because their functional groups changes, imparting a high binding affinity for various pollutants in water. In the same vein, this work covers recent advancements in the modifications and progresses in the domain of hydrogel technology with particular attention on polysaccharide-based hydrogel beads and their composites. These materials have been employed in removing various organic dyes and heavy metals from wastewater. Different types of polysaccharide-based hydrogel beads, as well as polysaccharide-based hydrogel beads composites used for the treatment of wastewater, are discussed in this chapter. Furthermore, the reader is provided with comprehensive experimental findings regarding the adsorption mechanisms and capacities of such hydrogel adsorbents for adsorbing contaminants from aquatic liquids. Lastly, we end this chapter with a look into some existing challenges and prospects of the polysaccharide-based hydrogel beads in water pollution remediation.

The main problem that the world is facing today is the scarcity of natural resources, including freshwater, due to ramping environmental pollution. It is primarily due to rapid industrialization posing a serious threat to the entire ecosystem. Most of the industries discharge effluents to the nearby wetlands and water bodies. As a result, the amount of usable water reduces drastically due to surface and ground waters contamination. The discharged effluents contain various toxic impurities in the form of metals, organic and inorganic particles, suspended solids, etc. If without proper treatment, the water is used, serious health hazards can occur. It is, therefore, necessary to treat the water before it is used for domestic and drinking purposes. There are many stages of treating natural wastewater for removal of organic, inorganic, and suspended loads. The primary process is to remove suspended inorganic solids and for that flocculation is generally used as it is one of the most convenient and cheapest unit operations. At the same time, it has also been found that polymeric flocculants are more effective than conventional inorganic flocculants for settling inorganic suspensions. It works both by charge neutralization and bridging mechanisms to settle the flocs in a reasonably quick time. This chapter vividly described the treatment of wastewater containing suspended inorganic solids with polysaccharide grafted hyperbranched copolymers as flocculants. Hyperbranched polymers have unique properties like higher solubility, higher hydrodynamic volume, more functional ends hence higher zeta potential for charge neutralization and more inner voids for bridging of flocs, which make them a better flocculant than conventional linear polymers. Along with hyperbranched polymer-based natural flocculants, future scope for incorporating various nanoparticles into the polymeric network for further improvement in flocculation efficiency, has also been discussed in this chapter.

Wastewater treatment includes the removal of undesirable organic and inorganic debris such as dyes and heavy metal ions from wastewater. The recent trend is the usage of green substances for wastewater treatment using the biomaterials such as chitosan, cellulose, starch etc. that are abundantly available in our environment. Using biopolymer-based composites, water treatment can be carried out by a simple adsorption method and it does not require any sophisticated instrumentation to implement the technique which will reduce the cost for commercialization. The efficiency of the adsorbent is improved through surface functionalization thereby tuning its physical and chemical properties interms of stability, dispersibility and specificity. Surface area is another important parameter that can be enhanced by tuning the shape and size of the adsorbent. Understanding the basic process behind the design of adsorbents and the type of interaction between adsorbents and adsorbate enables the calculated invention of new composites. In this chapter, we discuss the type of biopolymers used for treating wastewater, modification of biopolymers for effective adsorption, bionanocomposites used for water treatment, sustainability criteria for using such biomaterials for water purification, the type of interaction between the adsorbent and the pollutant and the practical difficulties in implementing the technique for commercialization.

The growing concern for ground and surface water contamination by arsenic metal has become a serious plight, for it has reportedly affected more than 100 million people worldwide. The increase in the prevalence of arsenic in the environment is reported due to the swift growth of industrial and agricultural activities, leading to the contamination of water resources. Sadly, exposure to environmental arsenic has been known to lead to biological ecosystem disruption in aquatic environments and cancer and death in humans. As a result, various technologies have been developed for arsenic removal, including precipitation, membrane processes, ion exchange, and adsorption. Among these methods, adsorption stands out owing to its high removal efficiency, easy operation, low cost, and absence of toxic sludge. The sorbent materials prepared from electrospun nanofibers have come to the forefront of arsenic uptake on account of the outstanding traits such as high specific surface area; which leads to increased sorption capacity, porosity, reusability, environmental friendliness, flexibility to surface functionalization and potential to conform to a wide range of physical and chemical conditions. This chapter provides an insight into the latest development of nanofiber-based composites as adsorbents for arsenic removal in water.

In recent years, wastewater treatment has been an utmost important endeavor adopted by several researchers around the globe. The alarming level of contamination caused by the continuous release of organic pollutants/effluents into water bodies from various industries such as textile, pharmaceutical, chemical, etc., has adverse effects in day-to-day life. The catalytic degradation of these organic pollutants (dyes) is a promising approach in the treatment of wastewater. The nanocomposites comprising biopolymers decorated with metal and metal oxide nanopaticles offer better applications due to their superior activity, ease of preparation, abundance, and ecological friendliness. Numerous nanocomposite catalysts have been prepared using variety of biopolymers (such as starch, cellulose, lignin, alginate, chitosan, silk, gelatin, gums, and resins) in combination with various metals/metal oxides/metal sulphides (such as Pd, Ag, Cu, CuO, and AgO) have been utilized for degradation of organic dye pollutants. These research findings encouraged us to write this chapter. Here, we include the recent developments in synthesizing novel biopolymer nanocomposites for degradation of a catalytic textile dye in wastewater treatment.

With the growth in civilization and industrialization, there is a rise in the release of organic dyes into water systems, which is causing serious public concern. Although adsorption using biopolymer-based hydrogels has proven to be an ideal technique for treating these dye contaminants from aqueous solutions, these hydrogels suffer from a lack of mechanical stability and recoverability compared to synthetic polymers. Herein, we review the low-cost synthesis of hybrid hydrogel nanocomposites to improve the mechanical stability and separation of the hydrogel in removing dyes from an aqueous solution. The literature reports hydrogels and their nanocomposites as noble adsorbents well-known for addressing water pollution issues. In adsorption technology, hydrogel nanocomposites act as absorbents, prominent to improve the performance of removal efficiency. This current chapter pays particular attention to some recent breakthrough development in water remediation based on hydrogels as efficient adsorbents. In-depth discussions on adsorption and various methods for the synthesis of hydrogels have been devoted to applications of these nanocomposites and are compared in this contribution to the removal efficiency of organic dyes from wastewater.

The practice of using zeolitic imidazole framework-8@graphene oxide (ZIF-8@GO) is increasing tremendously in membrane technology for wastewater treatment. This is not only due to the limitations posed by ZIF-8 or GO when used separately, but because of the interesting properties a composite of these materials (ZIF-8@GO) possesses, such as hydrothermal stability, porosity, crystallinity, hydrophilicity, and selectivity. Therefore, it is necessary to expand knowledge on the overall properties of the resultant ZIF-8@GO as well as the ZIF-8@GO incorporated into polymeric membranes. This chapter covers the literature on recent developments on ZIF-8@GO incorporated into polymeric membranes for wastewater treatment. The focus is on the morphological features, thermal and chemical stability, membrane performances i.e., rejection of pollutants from wastewater, water flux, selectivity as well as antifouling and or antibiofouling properties of these ZIF-8@GO embedded in polymeric membranes.