The high content of natural organic matter (NOM) is one of the challenging characteristics of peat water. It is also highly contaminated and contributes to some water-borne diseases. Before being used for potable purposes, peat water must undergo a series of treatments, particularly for NOM removal. This study investigated the effect of coagulation using aluminum sulfate coagulant and adsorption using powdered activated carbon (PAC) as a pretreatment of ultrafiltration (UF) for removal of NOM from actual peat water. After preparation and characterization of polysulfone (Psf)-based membrane, the system’s performance was evaluated using actual peat water, particularly on NOM removal and the UF performances. The coagulation and adsorption tests were done under variable dosings. Results show that pretreatment through coagulation–adsorption successfully removed most of the NOM. As such, the UF fouling propensity of the pretreated peat water was substantially lowered. The optimum aluminum sulfate dosing of 175 mg/L as the first pretreatment stage removed up to 75–78% NOM. Further treatment using the PAC-based adsorption process further increased 92–96% NOM removals at an optimum PAC dosing of 120 mg/L. The final UF-PSf treatment reached NOM removals of 95% with high filtration fluxes of up to 92.4 L/(m2.h). The combination of three treatment stages showed enhanced UF performance thanks to partial pre-removal of NOM that otherwise might cause severe membrane fouling.

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This study shows, for the first time, the synthesis of a carbonised pectin templated silica thin-film material. The aim of this work is to investigate the vibration of carbon groups of pectin–silica xerogels using infrared spectroscopy and curve-fitting software. Thin films were prepared using a two-step acid–base catalysed sol-gel method, employing tetraethyl orthosilicate as the main precursor. Various concentrations of pectin (0.1 wt%, 0.5 wt% and 2.5 wt%) were used as templating agents. These were firstly dissolved in glycerol, and mixed with the silica thin-film material. The sols was then dried in an oven at 60°C for 12 h, and calcined in air using rapid thermal processing at 300°C and 400°C for 1 h. The results show that the concentration of carbon groups for samples calcined under 400°C is higher than that of samples calcined at 300°C – especially in the region of 800 cm−1 for silica-carbon. This clearly shows that the calcination temperature influences the polymerisation of carbon group templates in the silica matrices.

This article provides details of a study that fabricated interlayer-free pectin template silica membranes and then employed them in a series of experiments for the desalination of brackish water using pervaporation. The main objective of this research is to investigate the performance of the membranes in the desalination application and to look at ways of improving their mechanical stability.

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.

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Wetland saline water has great potential to overcome water scarcity due to high salinity of intruded seawater. This work determines performance of silica membranes using organo catalyst applied for wetland saline water desalination via pervaporation and investigates the effect of calcination temperatures. These membranes were prepared from precursor tetraethyl orthosilicate (TEOS) for 3 h through sol-gel process refluxed at 0°C (membrane A) and 50°C (membrane B). The sols were dipcoated onto alumina (Al2O3) support for 4 layers followed by calcination for 1 h. Performance of membranes were evaluated by feeding wetland saline water through desalination at room temperature. Results show the water flux for membrane A were 0.27 & 0.15 kg.m-2.h-1 and salt rejection were 97.5 & 99 % as a function of calcination temperature (200 & 250°C), respectively. Furthermore, water flux of membranes B were 0.90 & 0.93 kg.m-2.h-1 and excellent salt rejection (>99.9 %) for both calcination temperatures. The highest water flux and salt rejection were found for membranes B. For both using citric acid under refluxed and calcination process, it gives more vibration of Si-C formation and membrane pores. This membrane is the very first and mesoporous organo silica membranes which is successfully fabricated from organo catalyst.

Water scarcity is still a pressing issue in many regions. The application of membrane technology through water desalination to convert brackish to potable water is a promising technology to solve this issue. This study compared the performance of templated TEOS-P123 and ES40-P123 hybrid membranes for brackish water desalination. The membranes were prepared by the sol–gel method by employing tetraethyl orthosilicate (TEOS) for the carbon-templated silica (soft template) and ethyl silicate (ES40) for the hybrid organo-silica. Both sols were templated by adding 35 wt.% of pluronic triblock copolymer (P123) as the carbon source. The silica-templated sols were dip-coated onto alumina support (four layers) and were calcined by using the RTP (rapid thermal processing) method. The prepared membranes were tested using pervaporation set up at room temperature (~25 °C) using brackish water (0.3 and 1 wt.%) as the feed. It was found that the hybrid membrane exhibited the highest specific surface area (6.72 m2·g−1), pore size (3.67 nm), and pore volume (0.45 cm3·g−1). The hybrid ES40-P123 was twice thicker (2 μm) than TEOS-P123-templated membranes (1 μm). Lastly, the hybrid ES40-P123 displayed highest water flux of 6.2 kg·m−2·h−1. Both membranes showed excellent robustness and salt rejections of >99%.