TY - JOUR

T1 - Determination of the photocatalytic deposition velocity

AU - Engel, A.

AU - Glyk, A.

AU - Hülsewig, A.

AU - Große, J.

AU - Dillert, R.

AU - Bahnemann, D.W.

N1 - Funding information: This work which was funded in part by the German Federal Ministry of Education and Research (contract no. 03X0069F, HelioClean – Nanotechnologisch funktionalisierte Baustoffe zur solarkatalytischen Luft- und Oberflächenreinigung“) was presented in part by R.D. at the 2nd International Conference on Photocatalytic and Advanced Oxidation Technologies for Treatment of Water, Air, Soil and Surfaces (PAOT-2), September 9–12, 2013, Gdansk, Poland, and the 3rd European Symposium on Photocatalysis (JEP 2013), September 25–27, 2013, Portorož, Slovenia. The authors thank Dr. Gerald Burgeth, Sto AG, for the cession of the paint samples. R.D. thanks the Leibniz University Hannover and Prof. Dr. D. Bahnemann for granting him a leave of absence.

PY - 2015/2/1

Y1 - 2015/2/1

N2 - Microscale atmospheric dispersion models have been employed recently to predict the possible effect of photocatalytically active surfaces on the air pollution in urban areas. These simulations use the photocatalytic deposition velocity as an input value. However, no generally accepted experimental method for the determination of the photocatalytic deposition velocity is available. Here a method to determine the photocatalytic deposition velocity is proposed which is based on ISO 22179-1 et seqq. specifying test methods for the determination of the air-purification performance of materials that contain a photocatalyst or have photocatalytic films on the surface. It is assumed that the rate of the photocatalytic surface reaction of a species i, AR i, is given by an expression having the mathematical form AR i= Ak iK ic i/(1+K ic i) where the kinetic parameters Ak i and K i are variables depending on the photon flux, the temperature, the humidity and the concentration of other pollutants. Under steady state conditions the mole balance of a differential volume of a fluid element inside the plug flow reactor described in the cited ISO standards reads Y= Ak iK iX-const(i). This equation is a linear equation of the two variables Y=ln(c in, i/c out, i)/(c in, i-c out, i) and X=A r/(q V(c in, i-c out, i)) where c in, i, c out, i, A r, and q V are the inlet and outlet concentration of the pollutant i under consideration, the irradiated photocatalytically active surface, and the volumetric flow rate through the photocatalytic reactor, respectively. It is argued that the slope Ak iK i of this equation is the demanded photocatalytic deposition velocity ν pc, i. Thus, the measurement of c out, i at varying c in, i makes the photocatalytic deposition velocity accessible.

AB - Microscale atmospheric dispersion models have been employed recently to predict the possible effect of photocatalytically active surfaces on the air pollution in urban areas. These simulations use the photocatalytic deposition velocity as an input value. However, no generally accepted experimental method for the determination of the photocatalytic deposition velocity is available. Here a method to determine the photocatalytic deposition velocity is proposed which is based on ISO 22179-1 et seqq. specifying test methods for the determination of the air-purification performance of materials that contain a photocatalyst or have photocatalytic films on the surface. It is assumed that the rate of the photocatalytic surface reaction of a species i, AR i, is given by an expression having the mathematical form AR i= Ak iK ic i/(1+K ic i) where the kinetic parameters Ak i and K i are variables depending on the photon flux, the temperature, the humidity and the concentration of other pollutants. Under steady state conditions the mole balance of a differential volume of a fluid element inside the plug flow reactor described in the cited ISO standards reads Y= Ak iK iX-const(i). This equation is a linear equation of the two variables Y=ln(c in, i/c out, i)/(c in, i-c out, i) and X=A r/(q V(c in, i-c out, i)) where c in, i, c out, i, A r, and q V are the inlet and outlet concentration of the pollutant i under consideration, the irradiated photocatalytically active surface, and the volumetric flow rate through the photocatalytic reactor, respectively. It is argued that the slope Ak iK i of this equation is the demanded photocatalytic deposition velocity ν pc, i. Thus, the measurement of c out, i at varying c in, i makes the photocatalytic deposition velocity accessible.

KW - Air purification

KW - Deposition velocity

KW - Heterogeneous photocatalysis

KW - Nitrogen oxide

KW - Titanium dioxide

UR - http://www.scopus.com/inward/record.url?scp=84911360451&partnerID=8YFLogxK

U2 - 10.1016/j.cej.2014.03.040

DO - 10.1016/j.cej.2014.03.040

M3 - Article

VL - 261

SP - 88

EP - 94

JO - Chemical engineering journal

JF - Chemical engineering journal

SN - 1385-8947

ER -