In Situ Synthesis of Photocatalytically Active Hybrids Consisting of Bacterial Nanocellulose and Anatase Nanoparticles

Abstract

Bacterial nanocellulose (BNC) is an extraordinary biopolymer with a wide range of potential technical applications. The high specific surface area and the interconnected pore system of the nanofibrillar BNC network suggest applications as a carrier of catalysts. The present paper describes an in situ modification route for the preparation of a hybrid material consisting of BNC and photocatalytically active anatase (TiO(2)) nanoparticles (NPs). The influence of different NP concentrations on the BNC biosynthesis and the resulting supramolecular structure of the hybrids was investigated. It was found that the number of colony forming units (CFUs) and the consumption of glucose during biosynthesis remained unaffected compared to unmodified BNC. During the formation of the BNC network, the NPs were incorporated in the whole volume of the accruing hybrid. Their distribution within the hybrid material is affected by the anisotropic structure of BNC. The photocatalytic activity (PCA) of the BNC-TiO(2) hybrids was determined by methanol conversion (MC) under UV irradiation. These tests demonstrated that the NPs retained their PCA after incorporation into the BNC carrier structure. The PCA of the hybrid material depends on the amount of incorporated NPs. No alteration of the photocatalyst's efficiency was found during repeated PCA tests. In conclusion, the in situ integration of photocatalytically active NPs into BNC represents an attractive possibility to extend its fields of application to porous filtering media for drinking water purification and air cleaning.

Antimicrobial functionalization of bacterial nanocellulose by loading with polihexanide and povidone-iodine

“…Within the HoLiR-plant, plane BNC fleeces with a thickness range of 2-50 mm can be produced [24]. The three-dimensional network was highly organized and not affected by this method of cultivation, neither were other BNC characteristics such as surface structure, cellulose I a content, crystallinity, water absorption value (WAV), water retention value (WRV), or tensile strength altered [24,53,54]. Loading of active compounds into the BNC could have a distinct effect on the material properties by alterations in the BNC network structure.…”

TiO2 hybrid photocatalytic systems: impact of adsorption and photocatalytic performance

“…Some previous reports indicate that the network of hydrogen bonds within cellulose sped up the nucleation and synthesis of TiO 2 nanoparticles, and might be adsorbed onto any specific facts of TiO 2 nanoparticles. In fact, as nanocellulose is very flexible, hydrophilic biopolymers that could be casted into films of different sizes and shapes and have functionalized surfaces demonstrate suitability for use as a matrix to disperse TiO 2 nanoparticles (Wesarg et al 2012). Also, the renewability, degradability, and non-toxicity of nanocellulose may alleviate concerns regarding negative environmental impacts (Kettunen et al 2011).…”

Cellulose‐Based Biotemplated Silica Structuring

“…The second one is that in a typical processing, consisting of soaking a cellulose template with TEOS and subsequent drying, the hydrolysis step must be considered the time-critical one. Typical exemplary routes are marked blue, [106,122,126,185] green, [120,203] , red, [141,204,205] and brown [107,206] . [192,196] Condensation is further accelerated by water removal, which also leads to the evaporation of unhydrolyzed and non-condensed alkoxide species and lowering material yield.…”

“…This is due to the fact that the formed silicic acid has a high tendency to condense to polysilicic acids and ultimately undesired spherical silica. (a), [106,184,207] (b), [171][172][173] (c), [188,204,205,208] (d,e), [106,209,210] (f), [141] (g), [211,212] (h,i), [120,203] (j), [213] (k), [107,206] (l), [106,122,123,169,214] (m), [120,203,215] (n), [141,186,[216][217][218] (o), [134,186,208,219] (p). It is therefore of advantage that cellulose itself is a weak acid.…”