Preparation and Characterization of Novel Polyvinyl Alcohol-Alginate Beads for Quorum Quenching Application in Membrane Bioreactors

Abstract

Quorum quenching (QQ) has emerged as an effective biofouling mitigation approach in membrane bioreactors. This study presents new approaches for preparing and characterizing polyvinyl alcohol (PVA) and alginate beads for QQ applications. The effects of change in concentration of PVA, crosslinking solution composition, and the impact of mixture dissolution method on physicochemical, acyl homoserine lactones incorporation (AHLs), and mechanical properties were investigated. Comparisons between evaporative, freeze, and supercritical CO2 drying techniques were followed to characterize textural and structural properties. Beads' structure, mechanical, chemical modification, and textural properties were characterized by scanning electron microscopy, texture profile analysis, Nitrogen physisorption, and attenuated total reflection Fourier transform infrared spectroscopy analysis. Changes in the concentration of PVA and mixture dissolution method impact the bead pore structure, swelling properties, and AHL incorporation. Changes in the composition of the primary crosslinking solution cause modifications in the beads’ chain and pore structure. Beads crosslinked using a primary crosslinking solution composed of boric acid and calcium chloride possess internal structures with high chain interconnection and hardness. Meanwhile, beads prepared by blending the boric acid and calcium chloride's primary crosslinking solution with sodium nitrate (named SN-BA) provided new bead types with pores resembling fingers. Nitrogen physisorption analysis revealed the beads have a surface area between 16.8 m2/g and 24 m2/g with dominating mesopores. The finger-like pores enhanced the AHL permeation compared to beads with interconnected polymer chains. SN-BA beads incorporated more than 30% of C6-HSL, 24% of C8-HSL, and 23% of C10-HSL.