| Innovative hybrid approach for enhanced PFAS degradation and removal: Integrating membrane distillation, cathodic electro-Fenton, and anodic oxidationPer- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that pose significant toxicity risks to humans and ecosystems. Traditional advanced oxidation processes using boron-doped diamond (BDD) anodes degrade PFAS in wastewater effectively but suffer from slow kinetics and high energy costs, limiting commercial application. This study introduces a hybrid process combining cathodic electro-Fenton (EF), anodic oxidation via a BDD anode, and membrane distillation (MD) to improve perfluorooctanoate (PFOA) degradation efficiency and reduce energy use. Increasing the current density from 50 to 500 A/m2 significantly raised the concentration of produced H2O2 from 0.25 mM to 2.3 mM, accelerating PFOA degradation and mineralization. At 50 A/m2, no mineralization of PFOA occurred in the EF/BDD process, while the EF/BDD-MD process achieved 45% mineralization due to increased PFOA concentration in the electrolytic cell. At 500 A/m2, the EF/BDD-MD process achieved 95% PFOA mineralization. Findings reveal that while EF-generated •OH radicals assist degradation, the BDD(•OH) anode was the primary driver, driving 80% of the reaction. This degradation was initiated by direct electron transfer at the BDD surface, followed by homogeneous and heterogeneous •OH radicals enhancing the degradation and mineralization process. The hybrid process also lowered energy consumption, making the treatment feasible for large scales.
University of Alberta | Publication | 2025-04-15 | Afrouz Yousefi, Yang, L., Soliu Ganiyu, Ullah, A., Gamal El-Din, M., Sadrzadeh, M. |
| Lignin Depolymerization: A Sustainable Strategy to Enhance the Separation Performance of Biopolymeric Polyester MembranesMembrane technology remains essential for water treatment and desalination. While polyamide thin-film composite (TFC) membranes dominate the industry, their susceptibility to fouling reduces efficiency and shortens operational lifespan. Advanced chemical modification strategies have been developed to overcome this challenge, aiming to improve membrane performance and durability. Polyester-based TFC membranes offer a promising alternative, providing a negatively charged surface. However, their lower salt rejection than polyamide membranes remains a key limitation. In this study, we investigated the application of depolymerized lignin, a naturally abundant biopolymer, as a phenolic monomer for fabricating polyester TFC membranes. The native lignin has a much larger molecular size compared to conventional monomers, which limits its diffusion and reactivity during membrane formation. We utilized a microwave-assisted depolymerization technique to fractionate lignin into smaller moieties, resulting in oligomeric/monomeric lignin with a lower molecular mass and higher reactive sites. This approach enabled faster membrane fabrication and significantly improved membrane performance. The membranes fabricated by depolymerized lignin exhibited substantially improved salt rejection, achieving up to 98.8 % for sodium sulfate and 54 % for sodium chloride removal. The developed membranes exhibited excellent antifouling properties, as demonstrated by sodium alginate fouling tests, with a flux recovery ratio of over 85 %. This research presents an innovative approach to enhancing non-polyamide TFC membranes, opening up new possibilities for eco-friendly and efficient membrane technologies in practical desalination applications.
University of Alberta | Publication | 2025-10-15 | Taghipour, A., Karami, P., Behzad Ahvazi, Ullah, A., Sadrzadeh, M. |
| pH-Fractionated lignin enables high-selectivity, chlorine-tolerant polyester thin-film composite nanofiltration membranesolyamide thin-film composite (TFC) membranes provide high permeability and strong ion rejection in nanofiltration and reverse osmosis, but oxidants like chlorine can impair their long-term performance. To overcome this, alternative chemistries are needed to improve durability while maintaining separation efficiency. Lignin-based polyester TFC membranes are promising, offering better antifouling and chlorine resistance. However, their lower salt rejection hampers wider adoption. Here, we used distinct molecular-weight fractions of lignin to fabricate polyester TFC membranes and assessed how fraction-specific physicochemical properties govern membrane structure and performance. Lignin was separated into five fractions (B1–B5) via pH fractionation. Among the resulting membranes, the B4-derived TFC (M-B4) achieved the best overall performance, delivering 98% rejection of Na2SO4 and 41% rejection of NaCl with a water flux of 45 LMH. The B4 fraction isolated at pH 3.1, with a smaller particle size and a high phenolic hydroxyl content (2.1 mmol g−1), yielded a highly crosslinked polyester with increased hydrophilicity and surface roughness. M-B4 also exhibited excellent antifouling performance, with a flux recovery ratio (FRR) of 99% after three cycles, and strong operational stability, with only a 2% reduction in Na2SO4 rejection and a 5.5% decrease in water flux after 12 h of extended filtration. Additionally, after four days of chlorine exposure, Na2SO4 rejection decreased by just 2%, while water flux increased by 9%. Finally, we performed a cost analysis for large-scale manufacturing and benchmarked the estimated production cost against reported prices for conventional polyamide TFC membranes. This innovative yet simple strategy positions lignin-based polyester membranes as sustainable and efficient alternatives to polyamide membranes. University of Alberta | Publication | 2026-04-15 | Taghipour, A., Karami, P., Behzad Ahvazi, Ullah, A., Sadrzadeh, M. |
| An Innovative Surface Modification Technique for Antifouling Polyamide Nanofiltration MembranesIn this study, we developed a novel surface coating technique to modify the surface chemistry of thin film composite (TFC) nanofiltration (NF) membranes, aiming to mitigate organic fouling while maintaining the membrane’s permselectivity. We formed a spot-like polyester (PE) coating on top of a polyamide (PA) TFC membrane using mist-based interfacial polymerization. This process involved exposing the membrane surface to tiny droplets carrying different concentrations of sulfonated kraft lignin (SKL, 3, 5, and 7 wt %) and trimesoyl chloride (TMC, 0.2 wt %). The main advantages of this surface coating technique are minimal solvent consumption (less than 0.05 mL/cm2) and precise control over interfacial polymerization. Zeta potential measurements of the coated membranes exhibited enhancements in negative charge compared to the control membrane. This enhancement is attributed to the unreacted carboxyl functional groups of the SKL and TMC monomers, as well as the presence of sulfonate groups (SO3) in the structure of SKL. AFM results showed a notable decrease in membrane surface roughness after polyester coating due to the slower diffusion of SKL to the interface and a milder reaction with TMC. In terms of fouling resistance, the membrane coated with a polyester composed of 7 wt % SKL showed a 90% flux recovery ratio (FRR) during Bovine Serum Albumin (BSA) filtration, showing a 15% improvement compared to the control membrane (PA). PE-coated membranes provided stable separation performance over 40 h of filtration. The sodium chloride rejection and water flux displayed minimal variations, indicating the robustness of the coating layer. The final section of the presented study focuses on assessing the feasibility of scaling up and the cost-effectiveness of the proposed technique. The demonstrated ease of scalability and a notable reduction in chemical consumption establish this method as a viable, environmentally friendly, and sustainable solution for surface modification. University of Alberta | Publication | 2024-07-03 | Taghipour, A., Karami, P., Sadrzadeh, M. |
| Green Nanoengineered Keratin Derived Bio‐Adsorbent for Heavy Metals Removal from Aqueous MediaExploiting poultry chicken feathers, a keratin-rich by-product offers a sustainable raw material for bio-adsorbents in water remediation. This study developed a bio-adsorbent from chicken feathers keratin (CFK), functionalized with surface-modified graphene oxide (SMGO). The bio-adsorbent was tested for adsorbing metal cations (Pb, Cd, Ni, Zn, Co) and oxyanions (As, Se, Cr) from water contaminated with 600 µg/L of each metal at pH 5.5, 7.5, and 10.5. Results showed optimal removal efficiencies at pH 7.5, with anions achieving ≥91.10% for As (III), ≥89.55% for Cr (VI), and ≥74.33% for Se (IV). Cations removal reached 96.34% for Co (II), 97.36% for Ni (II), 99.03% for Cd (II), 99.21% for Pb (II), and 59.06% for Zn (II). Kinetic studies indicated rapid initial uptake within the first 6 hours, reaching equilibrium at 24 hours. The bio-adsorbent maintained high adsorption capacities over four regeneration cycles with minimal efficiency loss, showing strong stability and reusability. Removal efficiency followed the order: Pb (II) 〉 Cd (II) 〉 Ni (II) 〉 Co (II) 〉 Zn (II), correlating with their ionic radii. Ni2+ adsorbed more effectively than Co2+ due to a smaller ionic radius and stronger electrostatic attraction. These findings highlight CFK-SMGO's efficacy in wastewater treatment, promoting bio-based sustainable adsorbents. University of Alberta | Publication | 2024-04-08 | Muhammad Zubair, Ullah, A. |
| Green polycaprolactone/sulfonated kraft lignin phase inversion membrane for dye/salt separationExploring environmentally friendly, renewable, and cost-effective raw materials is essential in sustainable membrane fabrication. This study presents a facile and scalable method for fabricating a green and biodegradable tight ultrafiltration membrane for dye/salt separation. This involves simply blending biodegradable polycaprolactone (PCL) with the low-cost biobased sulfonated kraft lignin (SKL) additive. Additionally, we employed acetic acid as a green alternative solvent to enhance the sustainability of the membrane fabrication process. The incorporation of hydrophilic SKL into the PCL matrix resulted in increased hydrophilicity (water contact angle changed from 72° to 56°), surface roughness (increased from 29 nm to 43.5 nm), and enhanced negative electrostatic charge of the membrane (−40 mV to −45 mV). The optimized PCL/SKL membrane (M3) exhibited excellent water flux (∼45 LMH) under 40 psi hydraulic pressure coupled with ∼98 % and ∼10 % rejection rates for reactive red (RR) dye and NaCl, respectively. Moreover, the M3 membrane maintained its exceptional dye/salt fractionation performance while separating the mixtures at low salt concentrations. However, with increasing salt concentration (1–50 g/L), the membrane's RR dye rejection declined from ∼90 % to ∼50 %, with a significant reduction in NaCl and Na2SO4 salts rejection (from ∼14 % to ∼1 % and ∼22 % to –∼1 %, respectively). The M3 membrane exhibited remarkable antifouling properties during dye and humic acid filtration with a high flux recovery ratio (>98 %) and low flux decline rate (<7 %). The PCL/SKL membrane also showed excellent stability and maintained consistent separation performance over a long period. Overall, the novel biodegradable PCL/SKL membrane prepared in this study presents a promising avenue toward sustainable membrane fabrication for wastewater treatment applications. University of Alberta | Publication | 2024-05-01 | Md Mizanul Haque Mizan, Masoud Rastgar Farajzadeh, Karami, P., Sadrzadeh, M. |
