Effects of process variables for NO conversion by double-layered photocatalytic mortar with TiO2 nanoparticles

Abstract

In this study, we prepared the double-layered photocatalytic mortar, where the top-layer has the mini-mum thickness of 2 mm. We investigated systematically the effects of various process variables (initial NOX concentration, TiO2 addition amount, UV-A radiation, gas flow rate and relative humidity) on pho-tocatalytic conversion of NOX and also the transient NOX conversions for changing ambient conditions of process variables with time. The higher the nano-TiO2 concentration in the mortar or UV-A radiation intensity is, or the lower the NOX gas flow rate or relative humidity is, the higher the NOX conversion effi-ciency is. As the initial concentration of NOX increases, NOX conversion efficiency decreases, but the amount of NOX conversion increases. It is confirmed that the prepared photocatalytic mortar could con-vert NOX in the air efficiently for various conditions of process variables. NOX conversion efficiencies in transient environmental conditions were equivalent to those in fixed conditions for the same process variables. This study provides strong basic data to apply the photocatalytic mortar to convert NOX effi-ciently using solar energy without the use of extra energy and can be easily extended to future applica-tions to infrastructures such as buildings, tunnels, or roads.(c) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.