Preparation and rheology of titanium dioxide nanoparticles loaded κ‐carrageenan hydrogel beads strengthened by mixed salts for multipollutant water remediation

Abstract

Hydrogel beads are emerging as alternate adsorbent material for the batch or continuous column treatment of dye wastewater. Polysaccharide-based gel beads are preferred for their uniform shape and size, large specific surface area, and easy separation by filtration and subsequent reuse. In this work, we prepare and rheologically characterize UV-active κ-carrageenan/TiO 2 beads for the adsorption and degradation of dyes. The 3-4 mm sized nanocomposite beads are formed by the extrusion of κ-carrageenan/TiO 2 gel solution in salt solutions. The maximum increase in modulus was observed with the addition of 1% w/v TiO 2 to κ-carrageenan and subsequent crosslinking with mixed salt of KCl and CaCl 2 . κ-carrageenan/TiO 2 beads crosslinked by mixed salt of KCl and CaCl 2 have higher adsorption capacity, as compared to beads crosslinked with single salt of KCl. The kinetic study indicated the chemisorption of Methylene Blue on the bead surface. κ-carrageenan/TiO 2 beads showed higher degradation for Methylene Blue and Nile Blue A than Rhodamine B in 5 and 50 ppm each multicomponent dye systems under UV irradiation. The κ-carrageenan/TiO 2 beads could form a porous column for the selective adsorption of positively charged dyes from a multicomponent dye system.

Rheology and Extrusion Printing of κ-Carrageenan/Olive Oil Emulsion Gel Tablets with Varying Surface Area to Volume Ratios for Release of Vitamin C and Curcumin

“…The FTIR spectra of the unloaded and drug-loaded κ-carrageenan/olive oil emulsion gels are shown in Figure S7. Table S1 describes the functional groups present in κ-carrageenan, olive oil, vitamin C, and curcumin. ,,− On formation of the κ-carrageenan/olive oil emulsion gel (OCR = 3:7), we observe additional peaks at 2923, 2853, 1743, 1462, and 721 cm –1 as compared to the κ-carrageenan powder. With the addition of vitamin C to the κ-carrageenan/olive oil (3:7) emulsion gel, new peaks at 1681, 1190, and 1111 cm –1 are detected.…”

Superparamagnetic Amine-Functionalized Maghemite Nanoparticles as a Thixotropy Promoter for Hydrogels and Magnetic Field-Driven Diffusion-Controlled Drug Release

“…This indicates that there was no persistent deformation of the material after the tension or strain was removed. Time-dependent behavior emerges as stress or strain is increased within the linear viscoelastic zone . The pace of stress or strain application affects its response, which is a mix of viscous flow and elastic deformation.…”

“…Timedependent behavior emerges as stress or strain is increased within the linear viscoelastic zone. 52 The pace of stress or strain application affects its response, which is a mix of viscous flow and elastic deformation. It can be clearly observed that the onset of slope change is diagonally shifted toward the right or higher shear rate region.…”

The role of additives in rheology and processing

“…Thareja et al characterize the rheology of such systems made with titanium dioxide (TiO 2 ) nanoparticles in an adsorbent polysaccharide (κ‐carrageenan) gel cross‐linked with mixed salts. [ 14 ] Neal, Calabrese, et al studied magnetically and thermo‐responsive materials. [ 15 ] They describe the influences of application of magnetic field and/or incorporation of nanosilica on phase change behavior in the material systems.…”