Electrostatic deposition of TiO2 nanoparticles on porous wood veneer for improved membrane filtration performance and antifouling properties

Abstract

Wood has been a promising water purifier material on account of its abundant natural transport channels, easy processing, and renewability, which is mainly focused on its utilization in growth direction for effective separation.Wood veneer manufacured from raw wood block has a reversed-tree pore structure, and possesses advantages of low cost, easy fabrication, material saving, and abundant sources. To realize its functionalization and practicable application for membrane separation, modification of wood veneer is prerequisite. Herein, thin wood veneer with disparate utilization direction of wood was developed to design filter membrane loading TiO2 nanoparticles for treatment of dye wastewater. Wood veneer with reversed-tree transport pathways exhibits unique porous structure, and filtering direction and wood growth direction is almost orthogonal generated numerous sinuous channels. Thereout, sufficient area for loading TiO2 nanoparticles and contacting pollutants as well as appropriate water transport pathways at significantly shrinking thickness of wood (the thickness of 0.2 mm) can be provide by these sinuous channels. TiO2 nanoparticles was first modified by (3-Aminopropyl)triethoxysilane with high positive charge, and immobilized on negatively charged wood surface through atmospheric impregnation via strong electrostatic attractive interaction. Vast quantities of exposed TiO2 nanoparticles on wood cell lumens significantly enhance the adsorption ability for dye contaminants, resulting in a high membrane separation performance. The flux of TiO2/wood veneer membrane can achieve high level of 636.94 L/(m2h) with considerable methylene blue removal of 99.9% at 0.01 MPa. Meanwhile, it shows good cycling stability as well as decent flexibility and excellent mechanical strength. Moreover, the designed membrane with photocatalytic function of TiO2 also displays impressive decontaminated and recycling ability. The flux can recover its pre-recession level after 10 h light irradiation. The designed TiO2/wood veneer with simple preparation process and excellent water treatment capacity exhibits promising results for practical wastewater treatment.