Conditional Optimization on the Photocatalytic Degradation Removal Efficiency of Formaldehyde using TiO2 – Nylon 6 Electrospun Composite Membrane

Abstract

Since the outbreak of the coronavirus disease in 2019, many people have adjusted their work and lifestyle to the new normal, such as purchasing takeaway dishes or utilizing food delivery services more frequently. This causes individuals to spend more time indoors. The health, comfort, and well-being of building occupants are directly impacted by indoor air quality, which is a significant issue. The main objective of this study was to investigate the optimal conditions for the treatment of gaseous formaldehyde using TiO2 – Nylon 6 electrospun composite membrane via photocatalytic oxidation. Response surface methodology (RSM) model with the Box-Behnken Design (BBD) was applied for experimental design and statistical analysis. Three factors (catalyst dosage, initial formaldehyde concentration, and gas flow rate) affecting the removal efficiency were studied. Three sets of experiments were conducted to compare the formaldehyde removal efficiencies of the following processes; the adsorption process, the photolysis process, and the photocatalytic oxidation process. From the results, it is obvious that the photocatalytic oxidation process yielded the highest removal efficiency (83.43%) as compared to the other two processes. The mechanism of the formaldehyde photocatalytic oxidation process can be described using the simplified Langmuir-Hinshelwood equation. The reaction follows a pseudo-first order reaction, with a rate constant of 0.0058 min–1. The optimal conditions were found to be at 80.0%w/w catalyst dosage, 7.0 ppm initial formaldehyde concentration, and 1.5 L/min gas flow rate which resulted in an 84.54% removal efficiency after 420 minutes of treatment period. Thus, the application use of the TiO2 – Nylon 6 electrospun composite membrane equipped with the UV light source could be a promising alternative technology for indoor air treatment.