Design and fabrication of polyurethane nano-fiber membranes modified with Titanium dioxide for treatment of Toluene vapors from air

Abstract

Background and purpose: Growing consumption of Volatile organic compounds, especially BTEX has been increased risk of exposure with these harmful chemical materials in variety industries and careers. According to their proven consequences and adverse health effects, regulatory organizations have legislated limited and controllable exposure levels for people who are in contact with them. This experimental study, focused on design and fabrication of polyurethane nanofiber membranes modified with titanium dioxide for capturing of Toluene vapors from air. Methods: In this study, Tio2/Fe nanoparticle was synthesized by the Sol-gel method. A 10 wt% PU solution was prepared by dissolving 10 gr of PU with two solvent DMF/THF (50:50 wt). samples with different amounts of Tio2/ Fe nanoparticle (0, 0.5, 1, 1.5, and 2 wt% PU) were shacked for 60 min. Afterward, modified solutions were ultrasonicated for 10 min to attain a homogenous solution. PU 10% solution and composite solutions, individually were loaded in electrospinning device and fabricated under the certain electrospinning parameters (the applied voltage, tip-to-collector distance, and solution feed rate were 25-27 kV, 9-11 cm, and less than 1 ml/hr, respectively). In order to evaluation the structure of synthesized nanoparticle, XRD and FTIR analysis were carried out. Also, morphological characteristics and specific surface areas of each electrospun membrane were investigated via FE-SEM and BET analysis, respectively. Fabricated membranes were kept in the desiccator for 12 hours. Finally, absorption efficiency % of electrospun nanofiber membranes was measured against the three concentrations of toluene (20, 60 and 100 ppm) in designed setup. Results: The results of this study showed that Tio2/Fe nanoparticle was successfully synthesized by the Sol-gel method and Anatase phase obtained as considerable polymorph. Incorporating Pure PU membrane with different amounts of Tio2/Fe caused changes in morphological characteristics of modified membranes; in which, increasing the nanoparticle’s concentration up to 1.5 % wt resulted into the fabrication of nanofiber with smaller diameter. BET results indicated that nanofiber with smaller diameter had noticeable specific surface area. Also, the outcomes of absorption test revealed that electrospun nanofibers had the noticeable absorption efficiency in contact with the maximum concentration of toluene (100 ppm). In the concentration of 100 ppm of toluene, PU/ 1.5 %wt with the thinner diameter and the highest specific surface area devoted the maximum adsorption capacity among other membranes. Discussion and Conclusion: According to the results of this study, it can be concluded that PU/ 1.5 %wt electrospun membrane had the feasible function in the capturing of toluene vapors. This type of membrane by capturing and decreasing the toxicity of toluene, can play an important role as absorption membrane in different practical fields.