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Techniques in Radiation Chemistry 1.1.1 “Joint innovative training and teaching/learning program in enhancing development and transfer knowledge of application of ionizing radiation in materials processing” (Project acronym: TL-IRMP) AGREEMENT NUMBER 2014-1-PL01-KA203-003611 Course module Total hours of lecture: 60 hours (6 ECTS) in URCA (05-15/09/2016) and 30 hours (3 ECTS) in KTU (03-07/10, 2016) learning programme Total hours of laboratory and exercises: 6 hours in URCA (09/09/2016) Total hours of laboratory and exercises: 6 hours in KTU (07/10/2016) PROF.DR. DİLEK ŞOLPAN ÖZBAY Hacettepe University Department of Chemistry 06800, Beytepe/Ankara-TURKEY Training/learning course in URCA (Sept 05-07,2016), Reims-FRANCE TL-IRMP This project has been funded with support from the European Commission. This publication reflects the views only of the author(s). Polish National Agency for the Erasmus+ Programme and the European Commission cannot be held responsible for any use which may be made of the information contained therein. Date: Oct. 2017 OUTLINE: 1. Radiation chemistry of liquid systems 1.1.Techniques in radiation chemistry 1.1.1. Steady-state techniques 1.1.2.Pulse radiolysis 2.Radiation chemistry of water and aqueous solutions 2.1. Water radiolysis 2.2.Radiolysis mechanism 2.3.Reactions of intermediates 2.3.1.Characteristic of primary and secondary products 3.Organic solvents/solutions 3.1.Alkanes, alken and aromatic hydrocarbons 3.2.Other organic molecules 3.3.Irradiation of monomer 4.Radiation chemistry of organic solids 4.1.Primary and secondary effects 4.2.Radiation yield 5.Changes in physical and chemical properties 5.1.Natural and synthetic polymers 5.2.Polymer crosslinking, degradation, grafting, curing 5.3.Sterilization of medical devices and drugs 3 4 Prof.Dr.Dilek SOLPAN OZBAY Head of Physical Chemistry Division, Department of Chemistry, Hacettepe University, 06800, Beytepe/Ankara-TURKEY E-mail: [email protected] RESEARCH INTERESTS -Radiation chemistry -Wood-polymer composites -The consolidation and conservation of historical wooden objects -Synthesis and characterization of homopolymers, copolymers and semi-interpenetrating polymer Networks -Hydrogels -Adsorption -The concentration and separation of some metals by using alloy membranes -Surface chemistry -Treatment of industrial wastewater -The determination of COD and BOD, DO values -The degradation and decoloration of textile dyes in wastewater by gamma-irradiation -Removal of some pollutants (such as textile dyes, pesticides…) by gamma-irradiation -The use of GC-MS-MS and IC in the determination of some degradation products and degradation mechanism -The investigation of synergetic effects of ozonation+gamma-irradiation, ozonation+UV for removing of some pollutants in water -The adsorption of heavy metal ions and some metals from water by using appropriate adsorbents -Grafting and antimicrobial polymers 5 Research in our laboratories is broadly organized around the following areas. A number of them are further broken down into subareas. Polymer Chemistry · Synthesis, characterization and modification of smart polymers, hydrogels, membranes and adsorbents · Controlled/Living polymerization techniques · Synthesis of reactive and functional polymers · Nanostructuring of polymers for molecular imprinting · Conductive polymer blends and composites based on polyaniline · Solution and complexation behaviors of polysaccharides (chitosan, alginate, etc.) Radiation Chemistry · Radiation synthesis of polymers, copolymers and hydrogels · Radiation induced crosslinking, degradation, grafting · Radiation induced degradation of water pollutants · Dosimetric responses of polymers, polymer blends 1. Radiation chemistry of liquid systems 1.1.Techniques in radiation chemistry 1.1.1. Steady-state techniques 1.1.2.Pulse radiolysis AA Atom of any element: Z X can be symbolized. N: Neutron number, Z: Proton number and includes the place of the element in the periodic table. Mass number A = N + Z 131131 53 I proton number (atomic number) : Z= 53, Mass number A = N + Z = 131 neutron number: N = 131-53 = 78 7 Nuclide: A Nuclide is a particular nucleus characterized by a defined atomic number and mass number. A Sodium nuclide. There are particular types of Nuclide. They are: Isotopes Isobars Isotones A= Mass Number. Z=Atomic Number n=Number of charge (+ or -) Isotopes: The atoms having same atomic number but different atomic mass number are called Isotope. Isobars: Nuclides having the same mass number but having the different Proton/Atomic number are called Isobar. Isotones: Atoms of different elements having different mass number and different atomic number but same neutron number are called Isotones. 8 9 Penetration of radioactive rays Alpha particles may be completely stopped by a sheet of paper, beta particles by aluminium shielding. Gamma rays can only be reduced by much more substantial mass, such as a very thick layer of lead. Radiation can be absorbed by substances in its path. For example, alpha radiation travels only a few centimetres in air, beta radiation travels tens of centimetres in air, while gamma radiation travels many metres. All types of radiation become less intense the further the distance from the radioactive material, as the particles or rays become more spread out. The thicker the substance, the more the radiation is absorbed. The three types of radiation penetrate materials in different ways. 10 Radiation types Types of scattered radiation from the atomic nuclei of radioactive materials shown in the following diagram Radiation Ionizing radiation Non-ionizing radiation Particle Wave Wave Neutron Alpha Beta Gamma X UV-Vis IR Micro waves Radio waves Radiation originating from atomic nucleus E>50 eV Radiation resulting from atomic orbit Electromagnetic Radiation Spectrum 11 12 13 4. Radiation chemistry of liquid systems 4.1.Techniques in radiation chemistry 4.1.1. Steady-state techniques 4.1.2.Pulse radiolysis •Nuclear chemistry (interests of the structures of the stable and unstable nuclei and nuclear reactions and the events related to them.) •Radiochemistry (interests about the chemistry of the material can be detected by the radiation they emitted. Issues with each of these two disciplines so that these are similar, nuclear chemistry and radiochemistry would be more appropriate to collect under the same name.) •Radiation chemistry (implies the chemical effects of interactions of ionizing radiation with materials.) a, b, g Radiation Source Object to be irradiated The total energy lost per unit path length by the primary charged particle is obtained by the sum of integrating over all losses occuring in hard and soft collisions. The total energy lost per unit path is called the Linear Energy Transfer (LET). 14 Radiation chemistry may be defined as the study of the chemical effects produced in a system by the absorption of ionizing radiation. Included in this definition are the chemical effects produced by radiation from radiactive nuclei (a, b-, and g rays ), by high-energy charged particles (electrons, protons, deuterons, etc.), and by electromagnetic radiation of short wavelength (x- rays with a wavelength less than about 250°A, i.e., with an energy greater than about 50 electron volts.) The chief difference between radiation chemistry and photochemistry lies in the energy of the radiation which initiates the reaction, the energy of the particles and photons concerned in radiation chemistry being very much greater than the energy of the photons causing photochemical reactions. Thus in photochemistry each photon excites only one molecule and, by the use of monochromatic light, it is often possible to produce a single, well- defined, excited state in a particular component in the system.The excites species are distributed essentially uniformly in any plane at right angles to the direction of the beam of light. In the radiation chemistry each photon or particle can ionize or excite a large number of molecules, which are distributed along its track.The high-energy photons and particles are not selective and may react with any molecule lying in their path, raising it to any one of its possible ionized or excited states. 15 TECHNIQUES IN RADIATION CHEMISTRY Two main basically different experimental approaches are used to investigate radiation chemical reactions. One of them is applied to detect, qualitatively or quantitatively determine intermediates and final products that are stable and do not change during the time of measurement. Such intermediates are ions or free radicals ‘frozen’ in solid matrices. The other approach uses time dependent measurement in order to observe intermediates or the build up final products (pulse radiolysis). 16 Steady-state techniques The final products of radiolytic reactions are analyzed by the usual analytical technique, like spectrophotometry, gas-chromatography, high-performance-liquid-chromatography (HPLC) and others. In the radiolytic investigations the conversion is generally very low, being on the order of 0.0001-0.001, therefore sensitive analytical techniques are needed. A new generation of techniques, for instance chromatographic and electrophoretic analytical instrumentation based on diode array technology now makes it possible to examine radiation chemical processes below 10 Gy dose (Barbara 1998). 17 In radiolytic reactions The main intermediates are excited molecules, cations, free electrons, anions and radicals. For the study of radical anions, cations and radicals formed in a solid matrix, e.g. in polymers, EPR spectroscopy is used since the 1950’s.
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