Physicochemical stability of calcium alginate beads immobilizing TiO₂ nanoparticles for removal of cationic dye under UV irradiation

Abstract

Recently, there have been considerable interests to immobilize photocatalyst in alginate beads for removing pollutants from water sources. However, the feasibility of using alginate beads in industry largely depends on its long‐term stability during operation. This study investigated the physicochemical stability of alginate/titanium dioxide beads (Alg/TiO2) when exposed to UV irradiation in aqueous environment. The degradation of Alg/TiO2 beads was evident because the diameter and mass of the beads was reduced by 12% and 40%, respectively, after 120 h of irradiation. A substantial amount of TiO2 was leached into the external medium. Consequently, the removal efficiency of model cationic dye was found to reduce after every process cycle. Morphological analysis showed the formation of cavities on the surface of the Alg/TiO2 beads. Interestingly, the blank alginate beads degraded more rapidly than the Alg/TiO2 beads, confirming the UV‐shielding effect of TiO2. Nevertheless, this study reveals the need to improve the UV stability of alginate‐based beads before they can be considered for practical application. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45002.

Immobilized TiO2 on glass spheres applied to heterogeneous photocatalysis: photoactivity, leaching and regeneration process

“…The LR value was obtained to be 0.03% of TiO 2 leached in water after 24 h. This LR value can be considered small when compared with data reported in other studies. For example, the LR of the TiO 2 immobilized on glass plates was found to be (1.52 ± 0.12%) after 10 h of stirring treatment ( Nawi et al, 2011 ), while in a recent study ( Lam et al, 2017 ) approximately 10% of the TiO 2 immobilized on glass beads was leached into water. In addition it was reported ( Jawad et al, 2016 ) that 7.3% of the TiO 2 of a TiO 2 /epoxidized natural rubber (ENR) immobilized on glass plates was leached after 4 h.…”

Fabrication of Multicore Milli- and Microcapsules for Controlling Hydrophobic Drugs Release Using a Facile Approach

“…Therefore, more cores were encapsulated in the capsule, the more easily the tocopherol was oxidized. After 10 h, the scavenging activity of tocopherol in millimeter capsules decreased significantly; it can be explained by the continuous destruction of UV light, since the capsule shell could only protect tocopherol from UV light to some extent but did not completely isolate from it, and the fact that the capsule’s shell became thinner due to the degradation of calcium alginate shell under ultraviolet irradiation . At 20 h, the scavenging activity of single-core capsules remained 36.09% and those of double-core and triple-core capsules were 19.35 and 2.39%, respectively.…”

Recent progress in sodium alginate based sustainable hydrogels for environmental applications

“…Sodium alginate based hydrogels have been used in wastewater treatment (Belhouchat et al, 2017;Bhattacharyya and Ray, 2015;Fan et al, 2013;Fatin-Rouge et al, 2006;Gao et al, 2011;Hosseinzadeh and Abdi, 2017;Karthiga Devi et al, 2016;Lakouraj et al, 2014;Lam et al, 2017;Lu et al, 2015;Mahdavinia et al, 2013;Ngah and Fatinathan, 2008;Rashidzadeh et al, 2015;Ren et al, 2016;Tally and Atassi, 2016;Thakur, 2016;Thakur et al, 2016;Thakur and Arotiba, 2017, n.d.;W. Wang et al, 2013bW.…”