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Wetland saline water is the enormous problem faced by rural people in Kalimantan, Indonesia. During rainy season, seawater intrudes wetland aquifer and turns water to saline. Application of membrane silica–pectin is eligible to solve this issue. Sadly, this water contains high concentration of organic matter that contributes to declining of membrane performance. Therefore, coagulation pretreatment is explored to enhance membrane filtration performance. The objective of this work is to investigate the optimum condition of coagulation pretreatment to enhance silica–pectin membrane performance for wetland saline water desalination. Sol gel process was employed to fabricate silica–pectin membrane and calcined via rapid thermal processing technique. Desalination was operated by pervaporation at 25–60°C. Maximum removal of organic matter UV254 was obtained at coagulant 30 g L−1 of 83.5% (pH 7). Combination processes between coagulation pretreatment and silica–pectin membranes offered high water flux at 60°C (12.2 kg m−2 h−1). The UV254 rejection of the feed water with coagulation is 43% higher than without applying coagulation pretreatment. Overall, salt rejection for all processes was extremely good (99.9%). Application of coagulation as pretreatment is promising to enhance performance of silica–pectin membrane for wetland water desalination. [ABSTRACT FROM AUTHOR]

Communities in some wetland areas in South Kalimantan, Indonesia, find it difficult to access clean water because surface water is contaminated by saltwater intrusion, especially during the rainy season. Membrane technology provides a solution to this problem by removing the salt contained in the raw water. The membranes used are generally composed of a porous material – thin-film – medium that functions to separate particles with a specific molecular size from the solution. The purpose of this study is to synthesise and fabricate silica-based membranes using an organo-catalyst calcined at a low calcination temperature (200°C and 250°C) through rapid thermal processing. In order to fabricate these membranes, the sol–gel method was applied, using tetraethyl orthosilicate as the silica precursor and citric acid as an organo-catalyst (refluxed at 0°C and 50°C). The results show that all membranes prepared with the organo-catalyst produce mesoporous structures. The highest surface area and pore size achieved were 354 m2/g and 0.215 cm3/g, respectively, refluxed at 0°C. Furthermore, silica-based membranes calcined at 250°C showed lower silanol concentration compared with those calcined at 200°C. In addition, the organo-catalyst (citric acid) acts as a carbon source in the silica matrices and may increase the hydrostability of the silica networks. [ABSTRACT FROM AUTHOR]