New nanoporous TiO2 with controlled porosities emanated from two concurrent correlative templates as potent adsorbents

Abstract

In a new attitude, nanoporous titanium oxides (NPTi) were synthesized using tetra heptylammonium bromide (THPAB) for the first time, accompanied simultaneously by the pluronic P123 co-polymer. In addition, varying the amount of the Ti source, the ratio of THPAB:P123 and the binary mixtures of 2-butanol/H2O as solvents led to six different NPTi samples, NPTi-1 to 6, which were synthesized under hydrothermal conditions. The samples were characterized using various techniques, including N2-sorption, XRD, TGA, FT-IR, SEM, TEM and HRTEM. As a result, the surface areas were determined to be in the range between 60 and 170 m2 g−1, while the morphologies were spherical, well-dispersed and nano-sized. Also, the pore diameters and pore volumes varied in the ranges 2.1 to 7.0 nm and 0.1 to 0.3 cm g−1, respectively. The HRTEM image exhibited a d space of 0.35 nm, which is assigned to the crystalline anatase phase. From the XRD results, it was also demonstrated that the structure of the walls were included by the anatase phase. These new nano adsorbents were applied to remove resorcinol (R) and hydroquinone (HQ). The optimal conditions of pH, adsorbent dosage, initial R and HQ concentration, effect of temperature and adsorption time were obtained as 6, 4 mg, 30 mg L−1 and 30 min, respectively. For the titania sample of NPTi-1 (with a pore volume of 0.3 cm g−1), under optimum conditions, the maximum adsorption capacity was 234.8 mg g−1, which was the best adsorbent for removing R and HQ pollutants. The experimental equilibrium data were analyzed using different isotherm models, such as Langmuir, Freundlich, pseudo-first and pseudo-second-order equations.