Titanium dioxide incorporated in cellulose nanofibers with enhanced UV blocking performance by eliminating ROS generation.

The preparation of sunblocks with dispersion stability, ultraviolet blocking, and photocompatibility remains a considerable challenge. Plant-derived natural polymers, such as cellulose nanofibers (CNF), show versatile traits, including long aspect ratio, hydrophilic nature, resource abundance, and low material cost. In the present study, a facile and cost-effective strategy is reported for the fabrication of nanostructured inorganic materials by incorporating natural polymers as interspersed, systematically nanosized titanium dioxide (TiO2) particles onto CNF. Among all experiments, the optimized TiO2@CNF3 showed higher ultraviolet blocking performance and less whitening effect. The outstanding performance is attributed to the engineering of equally dispersed nano-sized TiO2 particles on the CNF surface and stable dispersion. Significantly, TiO2@CNF3 exhibited excellent compatibility with avobenzone (80%), an oil-soluble ingredient used in sunblock products, illustrating the photoprotection enhancement under ultraviolet A (UVA) and ultraviolet B (UVB). Moreover, only 14.8% rhodamine B (Rho-B) dye degraded through photocatalytic oxidation process with the TiO2@CNF3, which is negligible photocatalytic activity compared to that of TiO2 (95% dye degraded). Furthermore, commercial inorganic and organic sunblock products with SPF lifetimes of 35+ and 50+ were modified using CNF, significantly enhancing the transmittance performance compared to that of the pure sunblock. However, it was also observed that hydrophilic CNF tended to demulsify the creams due to electrostatic disequilibrium. This CNF-based modified TiO2 system is a new window to replace effective sunblock products in high-value-added applications, such as cosmetics.

Visible light-driven photocatalytic rapid degradation of organic contaminants engaging manganese dioxide-incorporated iron oxide three dimensional nanoflowers.

Water pollution via hazardous organic pollutants poses a high threat to the environment and globally imperils aquatic life and human health. Therefore, the elimination of toxic organic waste from water sources is vital to ensure a healthy green environment. In the current work, we synthesized α-MnO2-Fe3O4 3D-flower like structure using a two-step hydrothermal method and explored the combination in a visible-light-assisted photocatalytic degrdation of dyes. The attained high specific surface area of 82 m2/g with mesoporous nature of α-MnO2 and Fe3O4 together can generate more active sites after exposure to visible light, leading to remarkable photodegradation performance. Significantly, twofold higher dye (methylene blue, MB (94.8%/120 min; crystal violet, CV (93.7%/120 min)) and drug (LVO 91%/90 min) photodegradations were observed with α-MnO2-Fe3O4 as catalyst than pure α-MnO2 and Fe3O4 at pH 6, respectively. This is attributed to the higher surface area and synergistic effect between Mn and Fe. More than 85% stability was observed with optimized catalysts employing MB and CV dyes, demonstrating the excellent reusability of the α-MnO2-Fe3O4. The underlying mechanism indicates that the formation of reactive oxygen species predominantly plays a role in the photodegradation of dyes under visible light. Consequently, these new insights will shed light on the practical applications of the α-MnO2-Fe3O4 3D-flower-like spherical structure for eco-friendly remediation via wastewater treatment.