Rita Kakkar

Bio: Rita Kakkar is an academic researcher from University of Delhi. The author has contributed to research in topics: Adsorption & Pharmacophore. The author has an hindex of 11, co-authored 73 publications receiving 479 citations.

Graphene-based adsorbents for water remediation by removal of organic pollutants: Theoretical and experimental insights

Abstract: Graphene-based materials have emerged as promising candidates as adsorbents for water treatment. The high surface area, low production costs, large porosities and robustness makes them excellent materials for adsorption studies and removal of toxic compounds such as pesticides, dyes, aromatic polar and non-polar compounds, nitro compounds, halogenated compounds, antibiotics, etc. from aqueous solutions. In recent years, there have been many structural modifications in the 2-D graphene sheet for synthesizing superior materials such as graphene-metal composites, metal oxide composites, bio-composites, hydrogels, etc. for improving the structural properties and widen its applications. In this review, we have incorporated the examples from both experimental and density functional theory studies (DFT) for water remediation by removal of toxic organic pollutants using graphene-based materials from the recent literature, and have further outlined the challenges and future perspectives in this direction.

DFT study of structural and electronic properties of gallic acid and its anions in gas phase and in aqueous solution

Abstract: Gallic acid, one of the naturally occurring antioxidants, has been characterized in terms of its structural and chemical properties using the density functional approach. The intramolecular interactions have been identified using natural bond orbital (NBO) analysis. The gallic acid anion and dianion have also been studied for determining the first two pK a values. Further, an investigation of the molecular orbitals reveals a dependence of the frontier molecular orbitals on external factors, viz. pH and dielectric of the medium. Consequently, the electronic spectra have been simulated in a range of solvents using steered molecular dynamics. Furthermore, the IR and NMR spectra of the neutral and the deprotonated state have been simulated. Additionally, the spectra have been experimentally recorded to validate the methodology followed. The present work also examines the variation in global and local reactivities of gallic acid under the influence of external factors. Each atom has been quantitatively assessed for its susceptibility towards nucleophilic, electrophilic, and radical attack.

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Abstract: : The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Nanomaterials: a review of synthesis methods, properties, recent progress, and challenges

Abstract: Nanomaterials have emerged as an amazing class of materials that consists of a broad spectrum of examples with at least one dimension in the range of 1 to 100 nm. Exceptionally high surface areas can be achieved through the rational design of nanomaterials. Nanomaterials can be produced with outstanding magnetic, electrical, optical, mechanical, and catalytic properties that are substantially different from their bulk counterparts. The nanomaterial properties can be tuned as desired via precisely controlling the size, shape, synthesis conditions, and appropriate functionalization. This review discusses a brief history of nanomaterials and their use throughout history to trigger advances in nanotechnology development. In particular, we describe and define various terms relating to nanomaterials. Various nanomaterial synthesis methods, including top-down and bottom-up approaches, are discussed. The unique features of nanomaterials are highlighted throughout the review. This review describes advances in nanomaterials, specifically fullerenes, carbon nanotubes, graphene, carbon quantum dots, nanodiamonds, carbon nanohorns, nanoporous materials, core–shell nanoparticles, silicene, antimonene, MXenes, 2D MOF nanosheets, boron nitride nanosheets, layered double hydroxides, and metal-based nanomaterials. Finally, we conclude by discussing challenges and future perspectives relating to nanomaterials.

Role of Nanomaterials in the Treatment of Wastewater: A Review

Abstract: Water is an essential part of life and its availability is important for all living creatures. On the other side, the world is suffering from a major problem of drinking water. There are several gases, microorganisms and other toxins (chemicals and heavy metals) added into water during rain, flowing water, etc. which is responsible for water pollution. This review article describes various applications of nanomaterial in removing different types of impurities from polluted water. There are various kinds of nanomaterials, which carried huge potential to treat polluted water (containing metal toxin substance, different organic and inorganic impurities) very effectively due to their unique properties like greater surface area, able to work at low concentration, etc. The nanostructured catalytic membranes, nanosorbents and nanophotocatalyst based approaches to remove pollutants from wastewater are eco-friendly and efficient, but they require more energy, more investment in order to purify the wastewater. There are many challenges and issues of wastewater treatment. Some precautions are also required to keep away from ecological and health issues. New modern equipment for wastewater treatment should be flexible, low cost and efficient for the commercialization purpose.