P. Ilaiyaraja

Bio: P. Ilaiyaraja is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Adsorption & Aqueous solution. The author has an hindex of 15, co-authored 32 publications receiving 636 citations. Previous affiliations of P. Ilaiyaraja include Indira Gandhi Centre for Atomic Research & VIT University.

Xanthate functionalized PAMAM dendrimer (XFPD) chelating ligand for treatment of radioactive liquid wastes

Abstract: Xanthate functionalized PAMAM dendrimer (XFPD) chelating ligand, first of its kind, has been synthesized from hydroxyl terminated poly(amido)amine dendrimer. Studies on performance of XFPD in removal of Cu 2+ and Eu 3+ metal ions were carried out from aqueous solution. Investigation on quantitative removal of Cu 2+ and Eu 3+ metal ions at various pH revealed that XFPD effectively precipitates the metal ions at pH > 4 with settling time of about 3 h. In case of Cu–XFPD complex at pH > 6, settling requires the addition of coagulating agent like aluminium sulphate. The loading capacity of XFPD for Cu 2+ and Eu 3+ metal ions was estimated to be 0.48 and 0.95 g g −1 , respectively. The XFPD chelating ligand deployed for treatment of radioactive liquid waste (RLW) showed that percentage removal of radionuclides were in the following order; 95 Zr ≈ 154 Eu ≈ 60 Co (>99.8) > 144 Ce (98.8) > 125 Sb (83.3) > 106 Ru (79.4) > 55 Mn (54.3) > 137 Cs (24.0). It has been demonstrated that XFPD chelating ligand has potential application in effective removal of various radionuclides from aqueous waste.

Actinide Speciation in Environment and Their Separation Using Functionalized Nanomaterials and Nanocomposites

Abstract: Actinides are the major and most important environmental contaminants associated with anthropogenic activities such as mining and milling of uranium ores, and generation of nuclear energy resulting in the production of nuclear reactor wastes. These actinides have greater migrating ability in aquifer systems. But actinides in aqueous environment exhibit an inordinately complex chemistry. As a result, the chemical interactions of actinides in the environment are difficult to understand unless a detailed knowledge on their chemical speciation, oxidation state, redox reactions, sorption characteristics, temperature and pressure profiles, pH, and redox potential (Eh) is available. The solubility and migration behavior are also related to these factors. To predict how an actinide might spread through the environment and how fast that transport might occur, we need to characterize all local conditions, including the nature of site-specific minerals, and ligand concentrations. A quantitative knowledge of the competing geochemical processes that affect the actinide’s behavior is also mandatory. Once actinides enter the environment; they pose major risk and hence safe management of radioactive waste with minimum impact to environment gains major importance in addition to speciation of actinides in environment. The major aim of radioactive waste management is to identify the chemical form of long-lived alpha-emitting radionuclide species spread in the environment and to separate them. Functional nonmaterial has gained wide attention and its increasing advancements in multidisciplinary research will make it a good candidate for separation of radionuclides. It is mainly because of their unique structure and exceptional properties. In this chapter, we discuss in detail the basic research progress in the speciation studies and separation of actinides in environment with the emphasis on application of functionalized nanomaterials and nanocomposites for the separation of radionuclides from the environment. 2 N. Priyadarshini et al.

Adsorption of U(VI) and Th(IV) from simulated nuclear waste using PAMAM and DGA functionalized PAMAM dendron grafted styrene divinylbenzene chelating resins

Abstract: The recovery of actinides such as U(VI) and Th(IV) from nuclear waste is a critical challenge and it requires the development of novel selective and high-capacity sequestering materials. Herein a novel chelating adsorbents are prepared by grafting poly(amido)amine (PAMAM) and diglycolamic acid (DGA) functionalized PAMAM dendron on styrene divinyl benzene (SDB) solid support. Adsorption of U(VI) and Th(IV) from simulated nuclear liquid waste (SNLW) using PAMAM–SDB and DGA–PAMAM–SDB chelating resins were carried out. Our studies have found that PAMAM–SDB and DGA–PAMAM–SDB chelating resins exhibited good adsorption selectivity for U(VI) and Th(IV) at pH 5.5 in presence of other metal ions. In addition, these chelating resins finds potential application for total decontamination of SNLW at pH 12. Hence, PAMAM–SDB and DGA–PAMAM–SDB are promising chelating resins for selective removal of U(VI) and Th(IV) and also total decontamination of aqueous radioactive waste.

Sustainable technologies for water purification from heavy metals: review and analysis

Abstract: Water pollution is a global problem threatening the entire biosphere and affecting the life of many millions of people around the world. Not only is water pollution one of the foremost global risk factors for illness, diseases and death, but it also contributes to the continuous reduction of the available drinkable water worldwide. Delivering valuable solutions, which are easy to implement and affordable, often remains a challenge. Here we review the current state-of-the-art of available technologies for water purification and discuss their field of application for heavy metal ion removal, as heavy metal ions are the most harmful and widespread contaminants. We consider each technology in the context of sustainability, a largely neglected key factor, which may actually play a pivotal role in the implementation of each technology in real applications, and we introduce a compact index, the Ranking Efficiency Product (REP), to evaluate the efficiency and ease of implementation of the various technologies in this broader perspective. Emerging technologies, for which a detailed quantitative analysis and assessment is not yet possible according to this methodology, either due to scarcity or inhomogeneity of data, are discussed in the final part of the manuscript.

Theory of the linear and nonlinear optical properties of semiconductor microcrystallites

Abstract: We analyze theoretically the optical properties of ideal semiconductor crystallites so small that they show quantum confinement in all three dimensions [quantum dots (QD's)]. In the limit of a QD much smaller than the bulk exciton size, the linear spectrum will be a series of lines, and we consider the phonon broadening of these lines. The lowest interband transition will saturate like a two-level system, without exchange and Coulomb screening. Depending on the broadening, the absorption and the changes in absorption and refractive index resulting from saturation can become very large, and the local-field effects can become so strong as to give optical bistability without external feedback. The small QD limit is more readily achieved with narrow-band-gap semiconductors.

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.

On the Structure of "秀才秀才,错字布袋

Abstract: Sentence patterns like "秀才秀才,错字布袋"are unique in the grammatical structure, semantic structure and pragmatic function. The typical feature of this pattern is that the same word or phrase reappears continually at the very beginning. It has two parts: (1) The proceeding part("秀才秀才") includes a word and its repeated form, which is different from the reduplication in grammar and the continual repetition in rhetoric. This part can have referential functions in particular situations;and (2) The main function of the last part ("错字布袋")is to interpret the proceeding one. It is the semantic focus of the whole sentence. This sentence pattern typically shows the features of proverbs like "秀才秀才,错字布袋"in language structure,semantic meaning and pragmatic function.