Controllable microfluidic fabrication of honeycomb capsule adsorbent via the one-step titration-gel method

Abstract

The hydrogel capsule adsorbent with honeycomb architectures was prepared via the one-step titration-gel method (OSTGM), which the casting solution contained polyvinyl alcohol (PVA), sodium alginate (SA) and tetraethyl orthosilicate (TEOS) were directly dripped into CaCl₂ and H₃BO₃ aqueous mixture through a controllable microfluidic device. The microscopic morphology and adsorbed capacity of the SA-PVA-SiO₂ capsules (SPSC) were absolutely depended on the parameter conditions during preparation. In this paper, at optimal synthesis situations [SA: PVA = 3: 7 (w: w), TEOS: (SA-PVA) = 2: 30 (v: w), the titration-gel distance was 14 cm and the feed flowed rate was 13 mL/h], the maximal removed capacity of the MB by the SPSC was 392.54 mg/g, and the SiO₂ NPs accounted for 17.94 wt % of the polymers. The prepared SPSC, also, could work in overly acid and alkaline aqueous solutions (pH 1-13). The authors of this manuscript hoped this work would provide a corresponding guideline for the researchers who are aiming at preparing the spherical hydrogel adsorbents for waste water treatments.

Graphical Abstract

Keywords:

• One-step titration-gel method
• spherical adsorbent
• hydrogel
• porous material
• polymer

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Research for this paper was supported by the National Key Research and Development Program of China [No. 2018YFC1902603], and the Key Project of the Joint Fund between the State Fund Committee and Shandong Province (U1806210; U1806212).