Membrane contactor performance for the dissolved methane recovery from the liquid effluent of a desulphurisation reactor for biogas purification: Evaluation of operating conditions, fouling and cleaning strategies

R. Jiménez-Robles, M. Izquierdo, V. Martínez-Soria, R. Hervás-Martínez, T. Montoya, F. Sempere.

Journal of Water Process Engineering. Num.Volume 71, March 2025, 107210.

Membrane contactors offer a promising feasible alternative to conventional desorption units due to their higher surface-to-volume ratio and operational flexibility. In this regard, a hollow fibre membrane contactor (HFMC) was coupled to a biogas desulphurisation reactor at pilot scale to recover the dissolved CH4 (D-CH4) present in the liquid effluent. To determine the effects of the operational parameters in the separation efficiency, different liquid (QL = 0.7–3 L min−1) and sweep gas flow rates (QG = 0.05–1 L min−1) were tested using a polypropylene HFMC. The D-CH4 removal efficiency (RE) was strongly dependent on the QL with a negligible effect of the QG, since the liquid phase boundary...

Membrane contactors offer a promising feasible alternative to conventional desorption units due to their higher surface-to-volume ratio and operational flexibility. In this regard, a hollow fibre membrane contactor (HFMC) was coupled to a biogas desulphurisation reactor at pilot scale to recover the dissolved CH4 (D-CH4) present in the liquid effluent. To determine the effects of the operational parameters in the separation efficiency, different liquid (QL = 0.7–3 L min−1) and sweep gas flow rates (QG = 0.05–1 L min−1) were tested using a polypropylene HFMC. The D-CH4 removal efficiency (RE) was strongly dependent on the QL with a negligible effect of the QG, since the liquid phase boundary layer governed the mass transport. Thus, REs up to 70 % were obtained at QL ≤ 1 L min−1 feeding the liquid through the shell side. On the contrary, the CH4 content in the recovered gas was always quite low (<20 %) due to the sweep gas dilution effect and the simultaneous desorption of CO2. In log-term operation, a considerable loss of efficiency was observed when fouling appeared, therefore, different physical and chemical cleaning strategies were investigated. The permanent decline in the RE suggested a significant amount of irreversible fouling which hindered the cleaning efficiency, denoting the need of preventive cleanings. The analysis of the fibre surface elucidated an organic dense fouling cake, biofouling from bacteria and algae, and anhydrite scaling (CaSO4). Importantly, this study demonstrated that this process is an attractive prospect to avoid diffuse emissions and recover an energy vector.

Bondades y retos en el uso de las botellas de plástico para el envasado del agua (cap.)

Gil Castell, Óscar ; Badia Valiente, José David.

Más claro, agua. Guía para un uso del agua más saludable y sostenible. Num.Col·lecció PUV - Publicacions Universitat de València

El grupo de investigación en materiales y sostenibilidad (MATS) de la Universitat de València ha colaborado en el reciente libro "Más Claro, Agua: Guía para un uso del agua más saludable y sostenible", editado por la Universitat de València e impulsado por la Cátedra de Cooperación y Desarrollo Sostenible y el Vicerrectorado de Sostenibilidad, Cooperación y Vida Saludable de la misma universidad, con el apoyo de la Generalitat Valenciana. En este contexto, Óscar Gil Castell y José David Badia Valiente han co-escrito el capítulo titulado "Bondades y retos en el uso de las botellas de plástico para el envasado del agua", en el que abordan una problemática de gran relevancia social y...

El grupo de investigación en materiales y sostenibilidad (MATS) de la Universitat de València ha colaborado en el reciente libro "Más Claro, Agua: Guía para un uso del agua más saludable y sostenible", editado por la Universitat de València e impulsado por la Cátedra de Cooperación y Desarrollo Sostenible y el Vicerrectorado de Sostenibilidad, Cooperación y Vida Saludable de la misma universidad, con el apoyo de la Generalitat Valenciana. En este contexto, Óscar Gil Castell y José David Badia Valiente han co-escrito el capítulo titulado "Bondades y retos en el uso de las botellas de plástico para el envasado del agua", en el que abordan una problemática de gran relevancia social y ambiental: el uso de botellas de plástico para el envasado de agua.

Mechanism and performance of the hydrolytic chemical recycling of polylactide catalyzed by the protic ionic liquid 2-HEAA

A. Cháfer, O. Gil-Castell, A. Björling, R. Ballesteros-Garrido, J.P.Cerisuelo-Ferriols, J.D.Badia

Resources, Conservation and Recycling. Num.Volume 210, November 2024, 107826

The hydrolytic chemical recycling of polylactide (PLA) aided by the protic ionic liquid 2-hydroxyethyl ammonium acetate (2-HEAA) as a homogeneous catalytic co-solvent was evaluated. In terms of maximization, temperature emerged as the most significant factor, being milder compared to that applied with other catalysts, resulting in potential energy savings. From a cost-efficiency perspective, employing a high solvent proportion was deemed unnecessary, thereby reducing reagent consumption. A higher proportion of ionic liquid leads to higher conversions, which could be trace-free recovered and reused in subsequent recycling steps. The best reaction triplet was a temperature of 140 °C, a mass...

The hydrolytic chemical recycling of polylactide (PLA) aided by the protic ionic liquid 2-hydroxyethyl ammonium acetate (2-HEAA) as a homogeneous catalytic co-solvent was evaluated. In terms of maximization, temperature emerged as the most significant factor, being milder compared to that applied with other catalysts, resulting in potential energy savings. From a cost-efficiency perspective, employing a high solvent proportion was deemed unnecessary, thereby reducing reagent consumption. A higher proportion of ionic liquid leads to higher conversions, which could be trace-free recovered and reused in subsequent recycling steps. The best reaction triplet was a temperature of 140 °C, a mass ratio between PLA and water of 1:6, and a mass ratio between PLA and 2-HEAA of 1:2.5, enhancing the efficiency of PLA conversion under a waste-to-gate circular model in the chemical valorization industry. Thermal kinetics explained by a first-order model, show an apparent activation energy of 112.3 kJ·mol-1, which is lower compared to other ionic liquids.

Keywords: Chemical valorization; Hydrolysis; Polylactide (PLA); Protic ionic liquid (PIL); 2-hydroxyethyl ammonium acetate (2-HEAA); MechanismsKinetics

Factorial Analysis and Thermal Kinetics of Chemical Recycling of Poly(ethylene terephthalate) Aided by Neoteric Imidazolium-Based Ionic Liquids

Oscar Gil-Castel, Ramón Jiménez-Robles, Alejandro Gálvez-Subiela, Gorka Marco-Velasco, M. Pilar Cumplido, Laia Martín-Pérez, Amparo Cháfer, Jose D. Badia.

Polymers. Num.16, 2451.

Poly(ethylene terephthalate) (PET) waste accumulation poses significant environmental challenges due to its persistent nature and current management limitations. This study explores the effectiveness of imidazolium-based neoteric solvents [Emim][OAc] and [Bmim][OAc] as catalytic co-solvents in the glycolysis of PET with ethylene glycol (EG). Reaction thermal kinetics showed that both ionic liquids (ILs) significantly enhanced the depolymerization rate of PET compared to traditional methods. The use of [Emim][OAc] offered a lower activation energy of 88.69 kJ·mol−1, thus making the process more energy-efficient. The contribution of key process parameters, including temperature (T),...

Poly(ethylene terephthalate) (PET) waste accumulation poses significant environmental challenges due to its persistent nature and current management limitations. This study explores the effectiveness of imidazolium-based neoteric solvents [Emim][OAc] and [Bmim][OAc] as catalytic co-solvents in the glycolysis of PET with ethylene glycol (EG). Reaction thermal kinetics showed that both ionic liquids (ILs) significantly enhanced the depolymerization rate of PET compared to traditional methods. The use of [Emim][OAc] offered a lower activation energy of 88.69 kJ·mol−1, thus making the process more energy-efficient. The contribution of key process parameters, including temperature (T), plastic-to-ionic liquid (P/IL) mass ratio, and plastic-to-solvent (P/S) mass ratio, were evaluated by means of a factorial analysis and optimized to achieve the maximum PET conversion for both neoteric solvents. The relevance sequence for both ionic liquids involved the linear factors T and P/S, followed by the interaction factors T×P/S and T×P/IL, with P/IL being the less significant parameter. The optimal conditions, with a predicted conversion of 100%, involved a temperature of 190 °C, with a P/IL of 1:1 and a P/S of 1:2.5, regardless of the IL used as the catalytic co-solvent.

Chemical recycling of post-consumer poly(ethylene terephthalate) (PET) driven by the protic ionic liquid 2-HEAA: Performance, kinetics and mechanism

J.D.Badia, R.Ballestero-Garrido, A. Gamir-Cobacho, O.Gil-Castell, A. Cháfer

The circular economy is a paradigm for the upcoming industrial era, in which plastic wastes must be focused on as new resources. Chemical valorisation permits deepening into waste-to-gate schemes by obtaining new chemical platforms to be reintroduced in the production market. In this context, the potential of the protic ionic liquid 2-hydroxyethyl ammonium acetate (2-HEAA) to be used as a homogeneous catalytic co-solvent for the glycolytic conversion of post-consumer poly(ethylene terephthalate) (PET) was validated from different perspectives. Studies were performed for the reaction triplet framed under the experimental conditions (i) temperature T [160,170,180 ºC], (ii) plastic-to-solvent...

The circular economy is a paradigm for the upcoming industrial era, in which plastic wastes must be focused on as new resources. Chemical valorisation permits deepening into waste-to-gate schemes by obtaining new chemical platforms to be reintroduced in the production market. In this context, the potential of the protic ionic liquid 2-hydroxyethyl ammonium acetate (2-HEAA) to be used as a homogeneous catalytic co-solvent for the glycolytic conversion of post-consumer poly(ethylene terephthalate) (PET) was validated from different perspectives. Studies were performed for the reaction triplet framed under the experimental conditions (i) temperature T [160,170,180 ºC], (ii) plastic-to-solvent mass ratio P/S [1:3, 1:4,1:5] and (iii) plastic-to-ionic liquid mass ratio P/IL [2:1, 2:2, 2:3]. The reaction was confirmed in terms of the transformation of PET into BHET (bis(2-hydroxyethyl terephthalate) and a proposal of mechanism induced by the amine group of the 2-HEAA is given. The thermal kinetics were modelled and a first-order equation and an apparent activation energy of 60.5 kJ·mol-1 were obtained. A statistical Box-Behnken design of experiments explained the relationship between the factors of the glycolysis triplet by a response surface, with a maximum around {T = 170 ºC, P/S = 1:3.75 and P/IL = 2:1.75}, being T and P/S statistically relevant, whereas only the presence of 2-HEAA and not its amount P/IL was significant. Finally, the reusability of 2-HEAA after 90-min glycolytic chemical valorisations was confirmed up to 4 cycles. The results position 2-HEAA as a promising catalytic co-solvent for the scale-up of chemical valorisation of PET.

Membrane-assisted reactive crystallisation for the recovery of dissolved phosphorus in vivianite form from liquid effluents

R. Jiménez-Robles, V. Martínez-Soria, M. Izquierdo, Lo-I. Chen, K. Le Corre Pidou, E.J. McAdam.

Separation and Purification Technology. Num.326, 2023, 124712.

Stability of Superhydrophobicity and Structure of PVDF Membranes Treated by Vacuum Oxygen Plasma and Organofluorosilanisation

Ramón Jiménez-Robles, Marta Izquierdo, Vicente Martínez-Soria, Laura Martí, Alicia Monleón, José David Badia.

Membranes. Num.13(3), 314.

Superhydrophobic poly(vinylidene fluoride) (PVDF) membranes were obtained by a surface treatment consisting of oxygen plasma activation followed by functionalisation with a mixture of silica precursor (SiP) (tetraethyl-orthosilicate [TEOS] or 3-(triethoxysilyl)-propylamine [APTES]) and a fluoroalkylsilane (1H,1H,2H,2H-perfluorooctyltriethoxysilane), and were benchmarked with coated membranes without plasma activation. The modifications acted mainly on the surface, and the bulk properties remained stable. From a statistical design of experiments on surface hydrophobicity, the type of SiP was the most relevant factor, achieving the highest water contact angles (WCA) with the use of APTES,...

Superhydrophobic poly(vinylidene fluoride) (PVDF) membranes were obtained by a surface treatment consisting of oxygen plasma activation followed by functionalisation with a mixture of silica precursor (SiP) (tetraethyl-orthosilicate [TEOS] or 3-(triethoxysilyl)-propylamine [APTES]) and a fluoroalkylsilane (1H,1H,2H,2H-perfluorooctyltriethoxysilane), and were benchmarked with coated membranes without plasma activation. The modifications acted mainly on the surface, and the bulk properties remained stable. From a statistical design of experiments on surface hydrophobicity, the type of SiP was the most relevant factor, achieving the highest water contact angles (WCA) with the use of APTES, with a maximum WCA higher than 155° for membranes activated at a plasma power discharge of 15 W during 15 min, without membrane degradation. Morphological changes were observed on the membrane surfaces treated under these plasma conditions, showing a pillar-like structure with higher surface porosity. In long-term stability tests under moderate water flux conditions, the WCA of coated membranes which were not activated by oxygen plasma decreased to approximately 120° after the first 24 h (similar to the pristine membrane), whilst the WCA of plasma-treated membranes was maintained around 130° after 160 h. Thus, plasma pre-treatment led to membranes with a superhydrophobic performance and kept a higher hydrophobicity after long-term operations.