Browsing by Author "Nair, N."

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Black titania: Turning the surface chemistry toward visible-light absorption, (photo) remediation of hazardous organics and H2 production
(Elsevier, 2022) Prekodravac, J.; Giannakoudakis, D.A.; Colmenares, J.C.; Nair, N.; Vasiljević, B.; Kepić, D.
Environmental protection and energy conversion by state-of-the-art photocatalysts emerge as imperative in pursuit for ideal, sustainable, and green oriented solutions. However, major drawbacks in broader application of one of the most promising semiconductor photocatalyst, titanium dioxide (TiO2), lie in the need for enhancing visible-light absorption and elevating the photocatalytic reactivity. Toward these directions, narrowing the material band gap and functionalization of the surface chemistry are among the most prosperous materials design approaches. As reported in earlier work, the surface structure engineering proved to be an encouraging approach to endow optical and electrical properties of the TiO2-based material. For the first time, the black powder of TiO2 with a disordered lattice and hydrogen surface doping was obtained through hydrogenation under high pressure and temperature, consequently leading to narrowing the optical band gap to 1.54eV. The presented chapter aims to reveal in-depth all the literature available information related to the black titania synthesis in addition of sharing in details its prosperous physicochemical properties. Feature information related to the photocatalytic activity of black TiO2 as well as of the most crucial features will also be provided. Finally, the chapter will conclude with the derived significant benefits of such material properties in photocatalytic treatment of organic pollutants and hydrogen production. © 2023 Elsevier Inc. All rights reserved.
Potential environmental applications of Helianthus annuus (sunflower) residue-based adsorbents for dye removal in (waste)waters
(Elsevier, 2022) Anastopoulos, I.; Giannopoulos, G.; Islam, A.; Ighalo, J.O.; Iwuchukwu, F.U.; Pashalidis, I.; Kalderis, D.; Giannakoudakis, D.A.; Nair, N.; Lima, E.C.
Under the framework of Circular Economy, agricultural residues that once were considered an unwanted byproduct, are currently gaining popularity as novel bio-based products for environmental applications. This chapter evaluates the potential of Helianthus annuus (sunflower) biomass residues for (waste)water dye removal considering the factors regulating its subsequent chemical processes and equilibria. The initial pH, which affects both the dye speciation in solution and the surface charge of the adsorbent, is one of the most critical parameters and determines the optimum conditions for efficient dye removal. The soluble dyes, that present a high affinity for water, are generally ionized (e.g., possess positive or negative charge), and therefore, the sorption capacities of an adsorbent are strongly affected by the initial pH of the dye solution. The equilibrium data regarding the removal of various dyes from aqueous solutions using sunflower-based adsorbents (in pristine or chemically modified form) are usually better described by the Langmuir equation; however, in some cases, the Freundlich adsorption model seems to better fit the experimental data. The majority of the kinetic data associated with the removal of dyes using sunflower-based adsorbents follows the pseudo-second-order model. In addition to the thermodynamic adsorption data, this chapter summarizes and discusses also data of desorption experiments performed using dye-loaded adsorbents. © 2022 Elsevier Inc. All rights reserved.
Remediation Analysis of Azo and Anthraquinone Dye by Modified Low Sulphonated Lignin
(World Research Association, 2022) Ankita Rao, K.; Murthy, T.P.; Nair, N.
Industrial wastes mostly consist of dyes and pigments which are known to cause detrimental effects on environmental and human health. Various techniques can be used for the removal of dyes, among them adsorption is by far the simplest and inexpensive one. Lignocellulosic biomass which consists of the second most abundant lignin is now increasingly being explored as an adsorbent due to its structural properties. In this study, the commercial low sulfonated lignin was modified by Mannich reaction i.e. amination and was employed in the adsorption of Reactive Blue 19 and Acid orange 10. Structural characterization like FTIR, SEM, TGA substantiates the presence of the amine group. From batch adsorption studies, almost >80% removal efficiency was found for the azo dye. Docking analysis was done to understand the active site interactions. © 2022 World Research Association. All rights reserved.
Role of coconut shell biochar and earthworm (Eudrilus euginea) in bioremediation and palak spinach (Spinacia oleracea L.) growth in cadmium-contaminated soil
(Academic Press, 2022) Noronha, F.R.; Manikandan, S.K.; Nair, N.
The contamination of soil with heavy metals is known to affect the yield the soil fertility, which in turn affects the growth of agricultural crops. This study investigates the role of coconut shell biochar (CSB) and earthworms (Eudrilus euginea) in the bioremediation and growth of Palak spinach (Spinacia oleracea L.) in cadmium (Cd) contaminated soil. The soils were amended with different combinations of CSB and earthworms and incubated for 35 days. Later, the soil samples were analyzed for the changes in the soil properties, soil enzyme activity, and heavy metal contents. It is observed that the treatments with both CSB and earthworms resulted in the improvement of soil properties and soil enzyme activity which was directly related to soil fertility. Meanwhile, the maximum removal of 94.38% of total Cd content in the soil was obtained for the soil sample contain both CSB and earthworms. The improved soil properties resulted in a higher germination percentage of Spinacia oleracea L. seeds in the Cd contaminated soil. © 2021 Elsevier Ltd
Soil toxicity and remediation techniques
(Elsevier, 2022) Manikandan, S.K.; Shilli, A.; Noronha, F.R.; Nair, N.
Soil is a major component required for the growth of plant, and its studies have been carried out intensively for enhanced agricultural production. The need to fulfill the food demands of the increasing human population and the requirement to safeguard food crops has resulted in the heavy usage of pesticides. However, the continuous usage of pesticides and their ability to persist in soil for a longer period has become a threat to society. The pesticide residue in the soil can cause severe environmental problems due to their high accumulative and persistent existence, that are biomagnified through the food chain of various life forms. Different disposal techniques classified as physicochemical technologies, biological technologies, and thermal technologies have been reported to be effective in pesticide removal from soil. Similarly, the application of green chemistry and nanotechnology have been stated to be effective for the removal of pesticides from the soil. This chapter provides detailed information on the various remediation involved in pesticide removal from soil. In addition, it also provides insights on the new technologies for treating contaminated soil and the economic aspect involved in the disposal of pesticides. © 2022 Elsevier Inc. All rights reserved.