1、Photocatalysis Glossary of termsPD CEN/TS 16981:2016BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06National forewordThis Published Document is the UK implementation of CEN/TS 16981:2016.The UK participation in its preparation was entrusted to TechnicalCommittee RPI/
2、13, Advanced technical ceramics.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions ofa contract. Users are responsible for its correct application. The British Standards Institutio
3、n 2017.Published by BSI Standards Limited 2017ISBN 978 0 580 93170 3ICS 01.040.25; 25.220.20Compliance with a British Standard cannot confer immunity fromlegal obligations.This Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 January 2017.Amen
4、dments/corrigenda issued since publicationDate Text affectedPUBLISHED DOCUMENTPD CEN/TS 16981:2016TECHNICAL SPECIFICATION SPCIFICATION TECHNIQUE TECHNISCHE SPEZIFIKATION CEN/TS 16981 November 2016 ICS 01.040.25; 25.220.20 English Version Photocatalysis - Glossary of terms Photokatalyse - Glossar der
5、 Begriffe This Technical Specification (CEN/TS) was approved by CEN on 15 August 2016 for provisional application. The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their comments, particularly on the question wh
6、ether the CEN/TS can be converted into a European Standard. CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in f
7、orce (in parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
8、 France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCH
9、ES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TS 16981:2016 EPD CEN/TS 16981:2016CEN/TS 16981:2016 (E) 2 Contents Page European foreword
10、 . 3 Introduction 4 1 Scope 5 2 Generalities . 5 2.1 Note on units . 5 2.2 Note on symbols . 5 2.3 Note on the relationship between spectral, radiometric, and photonic quantities 5 3 Terms and definitions . 6 Bibliography . 53 PD CEN/TS 16981:2016CEN/TS 16981:2016 (E) 3 European foreword This docume
11、nt (CEN/TS 16981:2016) has been prepared by Technical Committee CEN/TC 386 “Photocatalyse”, the secretariat of which is held by AFNOR. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsibl
12、e for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organisations of the following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finla
13、nd, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. PD CEN/TS 16981:2016CEN/TS 16981:
14、2016 (E) 4 Introduction Photocatalysis is a very efficient advanced oxidation technique which enables the production of active species following light absorption by the photocatalyst, such as bound/free hydroxyl radicals (OH), perhydroxyl radicals (OOH), conduction band electrons and valence band ho
15、les, capable of partly or completely mineralising/oxidising the majority of organic compounds. The most commonly used photocatalyst is titanium dioxide (TiO2), the latter being thermodynamically stable, non-toxic and economical. It can be used in powder form or deposited on a substrate (glass fibre,
16、 fabrics, plates/sheets, etc.). The objective is to introduce performance standards for photo-induced effects (including photocatalysis). These standards will mainly concern test and analysis methods. Safety statement Persons using this document should be familiar with the normal laboratory practice
17、, if applicable. This document cannot address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any regulatory conditions. Environmental statement It is understood that
18、some of the material permitted in this Technical Specification may have negative environmental impact. As technological advantages lead to better alternatives for these materials, they will be eliminated from this Technical Specification to the extent possible. At the end of the test, the user of th
19、e Technical Specification will take care to carry out an appropriate disposal of the wastes, according to local regulation. PD CEN/TS 16981:2016CEN/TS 16981:2016 (E) 5 1 Scope A common language for standards, disclosed to a wide audience and referring only to the operational protocols and to their o
20、utcomes, is needed both for a consistent set of standards and the connection with the scientific literature. This glossary will take into account existing glossary of terms used in photocatalysis and photochemistry. Because in photocatalysis numerous properties are difficult to be evaluated, it is s
21、trongly recommended in standard norms to avoid reporting properties depending on number of actives sites, the mechanisms of adsorption or kinetic mechanisms of photocatalytic reactions. For the same reason instead of the quantum yield and related quantities it is easier to report the photonic effici
22、ency. Most of the definitions reported in this Technical Specification are a sub-set of the IUPAC definitions in photocatalysis and radiocatalysis 1. Some other definitions, in particular for the photocatalytic rate and reactors are taken from a dedicated work 2. The use and many technical specifica
23、tions on the physical values suggested for irradiation conditions in the standards are reported in a separate Technical Specification 3. The arrangement of entries is alphabetical, and the criterion adopted by the IUPAC has been followed for the typeface used: italicized words in a definition or fol
24、lowing it indicate a cross-reference in the Glossary. 2 Generalities 2.1 Note on units SI units are adopted, with some exceptions, prominently in the use of the molar decadic absorption coefficient, , with common units dm3mol1cm1and a mole of photons denoted as an einstein. Note that “amount concent
25、ration” is the preferred term for what has been known as “molar concentration”, and is complementary to the terms “mass concentration” and “number concentration”. 2.2 Note on symbols Functional dependence of a physical quantity f on a variable x is indicated by placing the variable in parentheses fo
26、llowing the symbol for the function; e.g., (). Differentiation of a physical quantity f with respect to a variable x is indicated by a subscript x; e.g., the typical spectral radiant power quantity P= dP/d. The natural logarithm is indicated with ln, and the logarithm to base 10 with log. For the ma
27、gnitudes implying energy or photons incident on a surface from all directions, the set of symbols recommended by the International Organization for Standardization (ISO) 4 and included in the IUPAC “Green Book“, and by the International Commission on Illumination 5 are adopted, i.e., Hoor Fofor flue
28、nce, Eofor fluence rate, Hp,oor Fp,ofor photon fluence, and Ep,ofor photon fluence rate, note the letter o as subscript. This has been done primarily to comply with internationally agreed-upon symbols. It is important, however, to avoid confusion with the terms used to designate an amount of energy
29、(or photons) prior to absorption. In these cases, the superscript 0 (zero) is used. 2.3 Note on the relationship between spectral, radiometric, and photonic quantities When a quantity expressed in photonic units (Gp) covers a wavelength range (polychromatic irradiation between 1and 2), then Gpis the
30、 integral between 1and 2of the corresponding spectral photonic quantity, Gp(): Gp= 21Gp() d (e.g., spectral photon flux). PD CEN/TS 16981:2016CEN/TS 16981:2016 (E) 6 Since a spectral radiometric or energetic quantity at a given wavelength (Ge, e.g., spectral radiant power, P/Wnm1, is related to the
31、corresponding photonic quantity at the same wavelength (Gp, e.g., spectral photon flux / s1nm1) by the relation: Ge,= E() Gp,with E() = h c/, the energy of a photon of wavelength . The relation between photonic (Gp) and corresponding radiometric (or energetic, Ge) quantity is given by: Ge= h c 21Gp(
32、) 1/ d or, more useful in practice: Gp= (1/h c) 21Ge() d Therefore, for example, to calculate a photon flux over a wavelength interval, the spectral distribution of the radiant power is necessary. Note that in the Glossary no sub-index e has been used for the radiometric quantities. Radiometric quan
33、tities (Ge, as above, radiant power and others) are needed because lamp providers usually give the spectral distribution of the lamps in these units, and not in photonic units (Gp, photon flux and other photonic quantities) and because of quantification of radiation using, e.g., radiometers. 3 Terms
34、 and definitions For the purposes of this document, the following terms and definitions apply. 3.1 absorbance, Aelogarithm to the base 10 (linear absorbance) of the incident (prior to absorption) spectral radiant power, 0Pdivided by the transmitted spectral radiant power, P: ( ) ( )PATP= =0log log N
35、ote 1 to entry: T() is the (internal) transmittance at the defined wavelength. The terms absorbancy, extinction, and optical density should no longer be used. When natural logarithms are used, the napierian absorbance is the logarithm to the base e of the incident spectral radiant power, 0Pdivided b
36、y the transmitted spectral radiant power, P: ( ) ( )PATP= =0eln ln Note 2 to entry: These definitions suppose that all the incident ultraviolet, visible, or infrared radiation is either transmitted or absorbed, reflection or scattering being negligible. Attenuance should be used when this suppositio
37、n cannot be made. PD CEN/TS 16981:2016CEN/TS 16981:2016 (E) 7 Note 3 to entry: In practice, A is the logarithm to the base 10 of the spectral radiant power of ultraviolet, visible, or infrared radiation transmitted through a reference sample divided by that transmitted through the investigated sampl
38、e, both observed in identical cells. Note 4 to entry: In common usage, A is given for a path length of 1 cm, unless otherwise specified. Note 5 to entry: Traditionally, (spectral) radiant intensity, I, was used instead of spectral radiant power, P, now the accepted term. Note 6 to entry: The wavelen
39、gth symbol as a subscript for P and in parenthesis for T and A may be omitted. However, the wavelength should be specified for which the value of the particular property is reported. Note 7 to entry: Same as internal optical density, which is a term not recommended. Note 8 to entry: See also absorpt
40、ion coefficient, absorptance, attenuance, BeerLambert law, Lambert law, molar absorption coefficient. 3.2 absorbed (spectral) photon flux density number of photons of a particular wavelength, per time interval (spectral photon flux, number basis, qp, or spectral photon flux, amount basis, qn,p,) abs
41、orbed by a system per volume, V Note 1 to entry: On number basis, SI unit is s-1m4; common unit is s1cm3nm1. On amount basis, SI unit is mol s1m4; common unit is einstein s-1cm-3nm1Note 2 to entry: Mathematical expression: ( )0p,1 10AqVon number basis, ( )AqV0n,p,1 10on amount basis, where A() is th
42、e absorbance at wavelength and superscript 0 (zero) indicates incident photons. Note 3 to entry: Absorbed (spectral) photon flux density (number basis or amount basis) is used in the denominator when calculating a differential quantum yield and using in the numerator the rate of change of the number
43、, dC/dt, or the rate of change of the amount concentration, dc/dt, respectively. 3.3 absorbed (spectral) radiant power density spectral radiant energy per time interval (spectral radiant power, P) absorbed by a system per volume, V Note 1 to entry: SI unit is W m4; common unit is W cm3nm1. Note 2 to
44、 entry: Mathematical expression: ( )01-10APVwhere A() is the absorbance at wavelength and superscript 0 (zero) indicates incident radiant power. 3.4 absorptance, a fraction of ultraviolet, visible, or infrared radiation absorbed, equal to one minus the transmittance (T), i.e., (1 - T) Note 1 to entr
45、y: The use of this obsolete term, equivalent to absorption factor, is not recommended. Note 2 to entry: See also absorbance. PD CEN/TS 16981:2016CEN/TS 16981:2016 (E) 8 3.5 absorption (of electromagnetic radiation) transfer of energy from an electromagnetic field to a material or a molecular entity
46、Note 1 to entry: In a semiclassical fashion, this transfer of energy can be described as being due to an interaction of the electric field of the wave with an oscillating electric dipole moment set up in the material or molecular entity. This dipole moment is the result of the perturbation by the ou
47、tside field, and its oscillation frequency is given by the difference E of the energies of the lower and upper state in the absorbing material or molecular entity, E = h. When the frequency of the oscillating dipole moment and the frequency of the field agree, a resonance occurs and energy can flow
48、from the field into the material or molecule (an absorption occurs). Note 2 to entry: When energy flows from the material or molecule to the field, stimulated light emission occurs. Note 3 to entry: The oscillating electric dipole moment produced in the material or molecular entity has an amplitude
49、and direction determined by a vector Mif, known as the electric transition (dipole) moment. The amplitude of this moment is the transition moment between the initial (i) and final states (f). 3.6 absorption coefficient (linear decadic a or linear napierian ) absorbance, A(), divided by the optical pathlength, l: PAall P= =01()( ) log where 0Pand Pare, respectively, the incident and transmitted spectral radiant p
