Mesoporous, interlayer-free, hybrid carbon-silica matrices and membranes based on tetraethoxysilane (TEOS), organosilica of triethoxyvinylsilane (TEVS) and pluronic triblock copolymer poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (P123) were successfully prepared using an acid-base catalysed sol-gel method for desalination applications. These membranes were carbonized to form the hybrid carbon-silica structures under inert conditions in vacuum and nitrogen. The effects of calcination conditions on the structure-property relationship of the carbon-silica xerogels were elucidated, and the membrane performances were systematically studied using brackish (1 wt%) to brine (15 wt %) feed concentrations of sodium chloride solution and feed temperatures (25-60 °C) under pervaporation process. Vacuum calcined (CS-Vc) membrane produced a slightly more mesoporous matrix and higher carbon yield than the nitrogen calcined (CS-N 2) membrane, and hence, led to comparatively superior desalination performance. CS-Vc membranes produced high water fluxes of 26.5 (1 wt%, 60 °C) and 9.2 (15 wt%, 60 °C) L m-2 h-1 with salt rejections of 99.5% and 98.6%, respectively. This study demonstrates that the combined strategy of hybrid organosilica with polymeric template and 2 vacuum calcination offered the carbonized silica mesostructure membranes with excellent separation of water from the hydrated salt ions, and importantly, high water fluxes particularly for processing brine salt solutions.