Fig. 2: Characteristics and performance of fiber-based materials.

a Characterization of Si-fibers by SEM-EDS and FTIR analysis. b Turbidity removal following repeated reuse of Si-fibers and Si-microspheres (single experiment per condition) following 20 s settling time (for each cycle). Grafted materials were extracted, washed, and reused at least 20 times without loss of performance during solids removal. Shaded area (in grey) shows the industry standard after treatment (<1 NTU). c Flocs obtained with conventional treatment (left, formed with coagulant and flocculant only), Si-fiber (center) and Si-microsphere (right). Al-based flocs are expected to interact with cellulose and grafted Si via hydrogen bonding and electrostatic interactions. d Schematic of floc behavior in a settling tank. When combined with a coagulant and a flocculant, flocs formed with Si-microspheres settled 26 times faster than conventional flocs. Conditions for b-d: 30 mg/L coagulant (alum), pH 6.5 ± 0.2, the 0.30 mg/L of flocculant is composed of 50% starch and 50% polyacrylamide.