Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Fractionation of Guaiacyl and Syringyl-Lignin Units Using Organic Solvent Nanofiltration(Elsevier, 2026) Croes, Tim; Dutta, Abhishek; Van Aelst, Korneel; Sels, Bert; Van der Bruggen, Bart; Cornet, IrisA major obstacle to employing the full potential of lignin-based aromatics is the fractionation of the monomers present in lignin, specifically the separation of guaiacyl (G) and syringyl (S) units, which possess nearly identical molecular weights (196 Da versus 166 Da) and dimensions, and identical functional groups. Such similarities make their separation highly challenging using conventional techniques and are generally considered beyond the capabilities of size-based membrane processes. This study examines the feasibility of organic solvent nano-filtration for fractionation of guaiacyl and syringyl units, and how membrane and process parameters affect separation of these two molecules. Sixteen commercially available membranes were tested with methanol and ethyl acetate as solvents. The results demonstrate that, despite the extreme similarity of the solutes, selective separation is achievable and is primarily governed by membrane material and solvent selection rather than the pore size-based molecular weight cut-off. Polyimide-based solvent-resistant membranes exhibited the highest selectivity, with a maximum observed separation factor of 3.33 obtained using a DuraMemTM 500 membrane in methanol. These findings demonstrate the potential of nanofiltration to address previously unresolved separation challenges in lignin valorization and provide a basis for further process development.Article Citation - WoS: 2Citation - Scopus: 1A Novel Framework for Droplet/Particle Size Distribution in Suspension Polymerization Using Physics-Informed Neural Network (PINN)(Elsevier Science Sa, 2025) Turan, Meltem; Dutta, AbhishekA Machine Learning (ML) based neural network can capture the complex evolution of polymer chain distributions, accounting for factors such as initiation, propagation, and termination steps in a suspension polymerization process, by integrating stagewise molar balance model (MBM) and population balance model (PBM) with Physics-Informed Neural Network (PINN). The integrated PINN framework is proposed to efficiently solve these equations, incorporating known physical laws as constraints and minimizing errors in both the distribution and dynamics of the polymer chains. By optimizing the neural network parameters such as weight matrices and bias vector, the model reproduces the moments of the polymer molecular weight distribution in close alignment with numerical solutions, and it generates population balance solutions that exhibit excellent agreement with their analytical counterparts. Sensitivity analyses for the depth of the neural network architecture to quantify how structural choices affect model fidelity has been performed. The resulting MBM-PINN and PBM-PINN integrated framework demonstrates robustness and versatility in accurately capturing (96-97%) droplet/particle dynamics. The proposed methodology has the capability to provide a powerful tool for faster and scalable simulations of polymerization reactions, enabling better prediction of product properties which could be used for optimizing reaction conditions in industrial applications.Article Citation - WoS: 2Citation - Scopus: 2Further Developments of the Extended Quadrature Method of Moments To Solve Population Balance Equations(Cell Press, 2023) Turan, Meltem; Dutta, AbhishekDeveloping numerical methods to solve polydispersed flows using a Population Balance Equation (PBE) is an active research topic with wide engineering applications. The Extended Quadrature Method of Moments (EQMOM) approximates the number density as a positive mixture of Kernel Density Functions (KDFs) that allows physical source terms in the PBEs to compute continuous or point-wise form according to the moments. The moment-inversion procedure used in EQMOM has limitations such as the inability to calculate certain roots even if it is defined, absence of consistent result when multiple roots exist or when the roots are nearly equal. To address these limitations, the study proposes a modification of the moment-inversion procedure to solve the PBE based on the proposed Halley-Ridder (H-R) method. Although there is no significant improvement in the extent of variability relative to the mean of the tested shape parameter cr values, an increase in the number of floating point operations (FLOPS) is observed which the proposed algorithm responds in limitations mentioned above. The total number of FLOPS for all the kernels used for the approximation increased by around 30%. This is an improvement towards the development of a more reliable and robust moment-inversion procedure.Article Citation - WoS: 12Citation - Scopus: 14Extraction of Monophenols and Fractionation of Depolymerized Lignin Oil With Nanofiltration Membranes(Elsevier, 2023) Croes, Tim; Dutta, Abhishek; De Bie, Robin; Van Aelst, Korneel; Sels, Bert; Van der Bruggen, BartOrganic solvent nanofiltration membranes were employed to fractionate birch derived reductive catalytic fractionated (RCF) lignin oil. This lignin oil is highly depolymerized, with most, if not all chemical compounds lighter than 3 kDa. Sixteen commercially available membranes were investigated for the fractionation, in combination with methanol and ethyl acetate as solvents. Membrane performances were quantified using Gaussian fits of gel permeation chromatograms and separation factor calculations. The separation factor was found to be primarily based on affinities instead of size-exclusion. The silicon-based membranes from Borsig (Germany) and PuraMem S600 from Evonik (UK) proved best at separating lignin into different functional fractions, showing monomer separation factors up to 7.4 and providing a permeate fraction with 88 % phenolic monomer purity. These membranes were further examined in batch diafiltration and two-stage filtration. This increased the separation factor from 7.4 to 25.4, and the monomer purity of the permeate to 95 %, proving that membrane purification of the lignin-derived monophenols is technically feasible.Article Citation - WoS: 31Citation - Scopus: 38Resource Recovery From and Management of Wastewater in Rural South Africa: Possibilities and Practices(Elsevier, 2021) Montwedi, Masego; Munyaradzi, Mujuru; Pinoy, Luc; Dutta, Abhishek; Ikumi, David S.; Motoasca, Emilia; Van der Bruggen, BartThe continuous reduction in water resource availability is one of the major global societal challenges. Wastewater treatment plants (WWTP) play an important role in this, as they can provide water recovery. Furthermore, effective sanitation services lead to a significant reduction of health risks and protect the environment. However, WWTPs consume large amounts of energy to comply with discharge standards. At the same time, wastewater contains resources, which can be recovered for secondary uses, if treated properly. This is particularly useful for rural South Africa where challenges associated with water-based pollution, declining nutrients and water shortage, require a paradigm shift. This involves the transition of wastewater treatment plants into water, sanitation and resource (nutrients and energy) recovery facilities, leading further to social, economic and environmental sustainability. This process will involve the implementation of engineering tools for predictive modelling of the waste resource recovery systems. This review identifies the conceptual need for such a systematic shift from wastewater treatment to waste recovery facilities in rural South Africa. The targeted impact is to promote and help the uptake of the conversion of wastewater treatment systems into low cost and environmentally sustainable water and resource recovery facilities. Overall, the outlook is positive for the future use of these systems in South-Africa.