![]() In addition to the modification of the surface of cellulose I nanocrystals, the surfactant acts as a second template, which limits the actual value and role of the CNCs known by their original interesting properties. The use of cellulose I nanocrystals requires the addition of a surfactant in order to modify their surface. All these studies are based on the use of modified lignin-free CNCs (L-CNCs) prepared from commercial microcrystalline cellulose I and CTAB surfactant as templates in the preparation of silica nanorod materials. The cellulose nanofibers were coated with an ultrathin layer of the titania film in order to improve the adhesion of CTAB on its surface and then to facilitate the sol–gel reaction of tetraethyl orthosilicate (TEOS) to prepare silica/CNC composites. In their study of mesoporous silica nanotube production, dual templates of native cellulose fibers, and cetyltrimethylammonium bromide (CTAB) micelles were used. (27) found that it was not easy to obtain mesoporous silica tubes based on untreated CNCs. (26) also reported the synthesis of silica nanotubes using modified CNCs with oligopropylamino side chains in the medium of dimethyl sulfoxide as a template. (25) successfully obtained mesoporous silica material after template removal by coating cellulose nanorod nematic suspensions with the SiO 2 using sol–gel process. (24) prepared the nanostructured silica materials using CNCs as a template via the sol–gel procedure for their applications in ultrahigh-molecular-weight polyethylene composites. Silica nanorod materials with their unique optical and electronic features are promising in high-tech industrial applications such as wave guides in microphotonic devices, (20) nanoelectronics, (21) bioseparation, (22) and biosensing. The different silica structures showed excellent photodegradation of MB. This study provides a simple route to extract L-CNCs and CNCs as organic templates to prepare nanostructured silica. The photocatalytic degradation of MB dye was about 94, 98, 74, and 81% for B/L-CNC/nanoSiO 2, B/CNC/nanoSiO 2, C/L-CNC/nanoSiO 2, and C/CNC/nanoSiO 2, respectively. Also, the pore sizes were closely related to the dimensions of L-CNC and CNC templates, with high specific surface areas. By comprehensive analysis, it was demonstrated that the nanostructured silica were quite uniform and had a similar morphology as the templates. ![]() The obtained materials were denoted as B/L-CNC/nanoSiO 2, B/CNC/nanoSiO 2, C/L-CNC/nanoSiO 2, and C/CNC/nanoSiO 2, when the used L-CNC and CNC cores are from Beech and Cedar, respectively. The synthesis was performed with a simple and efficient sol–gel method using tetraethyl orthosilicate as the silica precursor followed by calcination at 650 ☌. Thanks to their interesting characteristics and their high crystallinity, these nanocrystals have been used without changing their surfaces as template cores for nanostructured hollow silica-free-surfactant synthesis for photocatalysis to degrade methylene blue (MB) dye. L-CNCs and CNCs derived from Beech fibers were long and thin and also had a higher crystallinity, compared with those obtained from Cedar fibers. It was shown that the properties of the extracted nanocrystals depend on the nature of the used sawdust (softwood or hardwood sawdusts). This work presents a new approach for more effective valorization of sawmill wastes (Beech and Cedar sawdusts), which were used as new sources for the extraction of lignin-containing and lignin-free cellulose II nanocrystals (L-CNCs and CNCs).
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