Phenol and benzoic acid recovery from end-of-life of polysulfone ultrafiltration membranes and its thermochemical kinetic behaviour

ABSTRACT

The remarkable properties of polysulfone (PSF) membranes have contributed to their use in many ultrafiltration applications. Meanwhile, this huge usage of PSF films and its short service life have generated a huge amount of waste PSF films that need to be managed carefully. Within this framework, this is the first research specifically developed to valorize the end-of-life of PSF membranes and convert them into high-value chemical and energy products using pyrolysis treatment. The treatment was performed using a thermogravimetric analyzer (TGA), while the structure and abundance of the phenol and benzoic acid compounds in the generated vapor were determined using Fourier-transform infrared (FTIR) spectroscopy and Gas chromatography-mass spectrometry (GC-MS). Thermogravimetric recorded data at different conditions (5–30°C/min) was subjected to linear and nonlinear models including KAS, FWO, Friedman, Vyazovkin, and Cai to assess the pyrolytic kinetic behavior of PSF films. The films showed higher content of volatile matter (57%), lower NOx emissions (0.321%), and a little bit more SO_X emission (6.909%). The GC-MS showed that the pyrolytic gaseous products are rich in phenol (24.3%) and benzoic acid (52.4%) compounds and the highest abundance was achieved at 30°C/min. Whereas activation energies were estimated in the range of 193–240 kJ/mol based on linear kinetic criteria versus 161–163 kJ/mol in the case of nonlinear models, where R² values (>0.91) indicated perfection. Also, distributed activation energy and independent parallel reaction kinetic models showed a good fit with the TGA-DTG experimental data with the minimum deviation. The study confirmed the potential of pyrolysis treatment in converting wasted PSF films into a new source for the recovery of phenolic and benzoic acid.

GRAPHICAL ABSTRACT

KEYWORDS:

• Polysulfone
• polymer membrane waste
• pyrolysis
• TG/FTIR-GC/MS analysis
• kinetic parameters

Highlights

• Pyrolysis behavior of PSF membranes were studied using TG/FTIR and GC/MS.

• Pyrolysis kinetics of PSF films were studied using linear and nonlinear models.

• Activation energies were estimated in the ranges of 161–163 kJ/mol.

• Phenol (24.3%) and benzoic acid (52.4%) were the major compounds in GC/MS.

List of abbreviation

Abbreviation	=	Definition
PSF	=	Polysulfone
TGA	=	Thermogravimetric analyzer
DTG	=	Derivative Thermogravimetry
FTIR	=	Fourier-transform infrared spectroscopy
GC-MS	=	Gas chromatography – mass spectrometry
KAS	=	Kissinger–Akahira–Sunose
FWO	=	Flynn–Wall–Ozawa
Ea	=	Activation energy
NOx	=	Nitrogen oxides
SOx	=	Sulphur oxides
A	=	Pre-exponential factor
Tm	=	Temperature at maximum reaction rate
Rmax	=	Weight loss rate
Ti	=	Initial temperature
Ci	=	The mass fraction of each of the three subcomponents
dy/dt	=	Conversion rate
h(x)	=	The numerically solve function
β	=	Heating rate
${\frac{\mathit{dm}}{\mathit{dt}}}^{\mathit{calc}}$	=	Differential weight loss calculated by the model
DAEM	=	Distributed activation energy model
IPR	=	Independent parallel reactions model
Dev.%	=	Deviation

Acknowledgments

This project has received funding from the Research Council of Lithuania (LMTLT), agreement No. S-MIP-23-118.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Ethical approval

In this study, there are no human and/or animal studies, thus we don’t need any ethical approval.

Author contributions statement

Samy Yousef: Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Writing – original draft, Writing – review & editing. Justas Eimontas: Conceptualization, Data curation, Formal analysis. Nerijus Striūgas: Conceptualization, Data curation, Formal analysis. Alaa Mohamed:Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Writing – original draft, Writing – review & editing. Marius Praspaliauskas: Conceptualization, Data curation, Formal analysis. Mohammed Ali Abdelnaby: Conceptualization, Data curation, Formal analysis, Software, Writing-review & editing.