Exploring the role of hydrogen peroxide dosage strategies in the photo-Fenton process: Scaling from lab-scale to pilot plant solar reactor

Abstract

This study aims to investigate the role of hydrogen peroxide (HP) continuous dosage in removing Paracetamol (PCT) from different water matrices using the solar photo-Fenton process. Different parameters in the HP dosage strategies (initial HP pulse, dosing time, and HP concentration) were systematically analysed to assess their impacts on pollutant removal (X_PCT), oxidant specific consumption ($Y_{HP/PCT}^t$), and toxicity levels (I(%)). The analysis involved various water matrices (ultrapure water UW, groundwater GW, anion matrix AW, and synthetic pharmaceutical wastewater IW0.01 or IW0.1), which were firstly treated in a laboratory reactor and subsequently scaled up to a solar prototype. After laboratory testing, the most effective reaction configuration (maximum X_PCT and $Y_{HP/PCT}^t$ close to the stoichiometric one) was chosen as the starting point for scaling up the reaction system. Using the solar reactor setup, complete PCT conversion was achieved within just 60 min of reaction time (UW matrix). However, under IW0.1 condition and employing the same HP dosing strategy, a X_PCT of 95.4 % was attained but at 180 min of reaction, highlighting the significant influence of the real matrix. Additionally, the I(%) remained high towards the end of the reaction (close to 60 %), attributed to the presence of hydroquinone in the system, demanding longer reaction times to completely reduce the toxicity when working with industrial wastewater. This comprehensive approach aims to close the gap between lab results and practical applications, offering crucial insights to address pharmaceutical wastewater pollution.