The performance of membranes interlayer-free silica-pectin templated for seawater desalination via pervaporation operated at high temperature of feed solution

Abstract

Recently, water scarcity is the big issues around the world. Especially in coastal area where the water distribution could not entranced and able to supply clean water for the citizen. The one and only solution is processing seawater to produce fresh and potable water. The desalination process using membrane was recommended to solve this issue. Due to that, the membrane with good structure and high hydro-stability was necessary to fabricate. The aim of this work is to investigate the performance of silica-pectin membranes for treating seawater by pervaporation employing silica based membranes. In this work, the silica-pectin membranes were successfully fabricated using Tetraethyl orthosilicate (TEOS) as silica precursor. Then, pectin from apple was also using in various concentrations (0; 0.1 to 0.5%). This organic material was implemented as a templating agent to produce in silica-pectin thin film. This thin films were dipcoated onto membranes support during membranes fabrication. These membranes were calcined in air at 300 and 400°C using rapid thermal processing (RTP) technique. All membranes were tested for water desalination via pervaporation set-up in various feed temperatures (25, 40 and 60°C). Results show that the membranes produced were crack-free and no pore dense. The FTIR-spectra and Fityk analysis refer to membrane of 2.5% at 300°C and 0.5% at 400°C are the optimum condition due to silanol and siloxane concentrations. An excellent performance was obtained at 0.5% at 400°C with water flux of 8.3 kg.m-2 .h-1 and high salt rejection of 99.4% at 60 °C of feed temperature. It clearly demonstrates that the silica-pectin membrane has a robust structures due to the templating of carbon chains into silica matrices. The presence of carbon chains in silica matrices may form the smaller and robust pores as expected, that makes the excellent salt rejection in high feed temperature.