Catalytic wet peroxide oxidation of paracetamol using carbon nanotubes synthesized from low-density polyethylene as model plastic waste
Conference Paper
Overview
Overview
abstract
One of the ongoing concerns related with wastewater treatment is the presence of micropollutants
on water bodies, since they accumulate due to its recalcitrant behavior and its constant
introduction in the system [1]. Catalytic Wet Peroxide Oxidation (CWPO) is a wastewater
treatment technology based on the generation of powerful oxidants (hydroxyl radicals) from the
decomposition of H2O2, providing that suitable solid catalysts are used, with promising results
being reported in the removal of pharmaceuticals [2]. On the other hand, plastic waste is an actual
concern in waste management, and alternatives to its post-use should be sought [3]. This study
aims at the CWPO of paracetamol (PCM) as model micropollutant, using as catalysts carbon
nanotubes (CNTs) synthesized from low-density polyethylene, as representative polymer found
in municipal plastic solid waste streams. The CNTs were synthesized by chemical vapor
deposition at 800 ºC, considering three catalyst based on Ni, Fe and Al prepared by coprecipitation
and wet impregnation methods. The synthesized CNTs were further tested on the
CWPO of PCM (100 mg L-1 of PCM, pH0 3.5, 474 mg L-1 H2O2, Ccatalyst
= 2.5 g L-1 and 80 °C).
All catalysts tested led to the complete conversion of both PCM and H2O2 after 24 h of reaction
time (Figure 1(a,b)), with a contribution of 23-42% of adsorption according to pure adsorption
tests performed at the same operating conditions (Figure 1(d)). The CNT synthesized on the
catalyst prepared by the impregnation method shows a lower contribution of adsorption and led
to a mineralization of 70% after 24 h of reaction time, with the highest efficiency of H2O2
consumption (determined as TOC conversion divided by H2O2 conversion).
This work was financially supported by project “PLASTIC_TO_FUEL&MAT – Upcycling Waste Plastics into Fuel
and Carbon Nanomaterials, POCI-01-0145-FEDER-031439, the Associate Laboratory LSRE-LCM
(UIDB/50020/2020) funded by national funds through FCT/MCTES (PIDDAC), and CIMO (UIDB/00690/2020)
through FEDER under Program PT2020.
