Mohammad Shahadat

A critical review on the prospect of polyaniline-grafted biodegradable nanocomposite

Among the various electrically conducting polymers, polyaniline (PANI) has gained attentions due to its unique properties and doping chemistry. A number of electrically conducting biodegradable polymers has been synthesized by incorporating a biodegradable content of cellulose, chitin, chitosan, etc. in the matrix of PANI. The hybrid materials are also employed as photocatalysts, antibacterial agents, sensors, fuel cells and as materials in biomedical applications. Furthermore, these biodegradable and biocompatible conducting polymers are employed in tissue engineering, dental implants and targeted drug delivery. This review presents state of the art of PANI based biodegradable polymers along with their synthesis routes and unique applications in diverse fields. In future, the synthesis of PANI-grafted biodegradable nanocomposite material is expected to open innovative ways for their outstanding applications.

Regeneration performance of clay-based adsorbents for the removal of industrial dyes: a review

The present review covers the regeneration capacity and adsorption efficiency of different adsorbents for the treatment of industrial dyes to control water pollution. Various techniques and materials have been employed to remove organic pollutants from water; however, adsorption techniques using cost-effective, ecofriendly, clay-supported adsorbents are widely used owing to their simplicity and good efficiency. Among all the natural adsorbents, activated carbon has been found to be the most effective for dye adsorption; however, its use is restricted due to its high regeneration cost. Clays and modified clay-based adsorbents are the most efficient clarifying agents for organic pollutants as compared to activated carbon, organic/inorganic, and composite materials. Regeneration is an important aspect to stimulate the adsorption efficiency of the exhausted/spent adsorbent for water treatment. A number of techniques, including chemical treatment, supercritical extraction, thermal, and photocatalytic and biological degradation, have been developed to regenerate spent or dye-adsorbed clays. This review discusses how these techniques enhance the adsorption and retention potential of spent low-cost adsorbents and reflects on the future perspectives for their use in wastewater treatment.

CHAPTER 5:Mechanism of Adsorption on Nanomaterials

The disposal of large amounts of wastewater containing organic, inorganic and biological pollutants has become a serious issue today. Many technologies have been established for pollutant removal, including chemical oxidation/reduction, biological treatment, coagulation/flocculation, adsorption, membrane separation, and ion exchange. The most effective among them is the adsorption process because it is simple, highly efficient, and easy to operate. Adsorption is a surface phenomenon that takes place by physical forces but sometimes, weak chemical bonding also participates in the adsorption process. Different models, like Langmuir, Freundlich, Halsey, Henderson, intraparticle diffusion, and Lagergren, are used to explain the results of adsorption. A thermodynamic study is carried out to determine the feasibility of the process by interpreting the values of enthalpy, free energy, entropy, and energy of activation. Recently, a great deal of attention has been focused on the application of nanostructured materials as sorbents to remove toxic and harmful substances from aquatic media. Nanostructure sorbents, which include metal nanoparticles, carbon nanomaterials and dendrimers, as compared to traditional materials have exhibited much higher efficiency and faster rates in water treatment with enhanced redox and photocatalytic properties.

The role of nanostructures in various wound dressings

Abstract Preventing infection and retaining sufficient moisture around wounds are the most challenging issues in wound healing. This chapter describes the fabrication of dressings for the treatment of wounds using various nanostructured materials. Silver nanoparticles (Ag NPs) have been effectively used in wound dressings due to their large surface area, which gives significant anti-inflammation, antimicrobial and wound-healing properties. Furthermore, Ag NPs have received substantial attention in wound healing due to their faster release of Ag ions than bulk Ag. Besides nanoparticles of silver (NS), nature-inspired materials such as chitin and chitosan, individually or associated with NS and other metal ion entities, have been employed in wound dressings because of their antifungal and bactericidal efficacy and their ability to maintain oxygen permeation into wounds and burns. A number of chitin- and chitosan-based nanohydrogels (e.g., membranes, fibers, sponges and scaffolds) have been fabricated to improve the wound-healing capacity of dressings. The physicochemical properties of NS and chitosan–NS wound dressings have been observed using scanning electron microscopy and transmission electron microscopy, and their chemical and microstructural properties have been analysed using energy-dispersive X-ray analysis, infrared resonance spectroscopy and X-ray diffraction. This chapter discusses advanced findings of different NS and chitosan–NS formulations, and their efficacy and safe usage in antiseptic and antibacterial dressings to treat wounds and burns. It anticipates that wound dressings supported by chitosan/chitin–Ag NPs have enormous potential for other biological applications in the field of medical sciences.

Pollutant Decontamination from Water: Role of Nanocomposite Materials

Rapid industrialization, urbanization, population growth, and climate change are responsible for contamination and depletion of water resources. Scarcity of fresh and pure water is considered as a biggest threat to human and animal life. For the last two decades, water purification technologies are gaining more and more attention of the public and governmental bodies. Researchers around the globe are focusing on nanotechnology-based water purification/treatment systems for efficient and effective decontamination of water bodies. Nanoscale composite materials have a huge potential to decontaminate water in several ways, due to their high surface area, excellent mechanical strength, high chemical reactivity, and cost-effectiveness. Nanoscale materials are able to remove bacteria, viruses, and inorganic and organic materials from wastewater due to specific binding action (chelation, absorption, ion exchange). A number of nanocomposite materials are playing active role in water purification, for example, metal nanoparticles, bioactive nanoparticles, nanosorbents, nanocatalysts, nanomembranes, carbon nanotubes, many other nanoforms, etc. This chapter discusses the application of different nanocomposite materials in the treatment of wastewater along with their mechanistic approach.