Muthia Elma

Performance and Long Term Stability of Mesoporous Silica Membranes for Desalination

This work shows the preparation of silica membranes by a two-step sol-gel method using tetraethyl orthosilicate in ethanolic solution by employing nitric acid and ammonia as co-catalysts. The sols prepared in pH 6 resulted in the lowest concentration of silanol (Si–OH) species to improve hydrostability and the optimized conditions for film coating. The membrane was tested to desalinate 0.3–15 wt % synthetic sodium chloride (NaCl) solutions at a feed temperature of 22 °C followed by long term membrane performance of up to 250 h in 3.5 wt % NaCl solution. Results show that the water flux (and salt rejection) decrease with increasing salt concentration delivering an average value of 9.5 kg m–2 h–1 (99.6%) and 1.55 kg m–2 h–1 (89.2%) from the 0.3 and 15 wt % saline feed solutions, respectively. Furthermore, the permeate salt concentration was measured to be less than 600 ppm for testing conditions up to 5 wt % saline feed solutions, achieving below the recommended standard for potable water. Long term stability shows that the membrane performance in water flux was stable for up to 150 h, and slightly reduced from thereon, possibly due to the blockage of large hydrated ions in the micropore constrictions of the silica matrix. However, the integrity of the silica matrix was not affected by the long term testing as excellent salt rejection of >99% was maintained for over 250 h.

Biocomposite Materials of Eleocharis dulcis Fibers with Iron (III) Nanoparticles and Its Potential for Sasirangan Textile Wastewater Treatment

Eleocharis dulcis (Chinese water chesnut), locally Kalimantan named Purun Tikus, is a plant that grown in highly acidic swamps areas in South Kalimantan. Eleocharis dulcis (ED) , was usually used as material for traditional handicrafts. Therefore it is necessary for develop and innovate to convert the material becomes valuables. This research focus on the study of biocomposite nanoparticles of ED and its potentials as an adsorbent to reduce concentration of Pb 2+ ion, Total Suspended Solid (TSS) and color from Sasirangan textile industry wastewater. The synthesis of the biocomposite nanocomposite was made by solvothermal synthesis. Firstly, ED stemsdried was cutted to small size (250 micron), then through delignification process to eliminate lignin by 1% w/v NaOH solution. ED delignification put into hydrothermal reactor, right afterward was carried out by one-pot solvothermal reaction of 1,6-diaminohexane, iron (III) chloride hexahydrate, and ethylene glycol at 200 o C for 6 h.The process was produced two types of biocomposites, without the amino group (EDB-M) and the amino group (EDB-MH). The characterization results shown by SEM, magnetic nanoparticles have been formed on the surface of EDfiber.The ED biocomposite nanoparticles (EDB) with diameter size around 30–50 nm could be obtained. X-Ray Diffraction (XRD) analysis showed treatment of EDdelignification was increased the porosity of the fiber, shown by increased Crystalinity Index (CrI) about 72.75%. The biocomposites adsorbent, EDB-M and EDB-MH had adsorption capacity for Pb 2+ ions about 44.21 mg/g and 55.62 mg/g at equilibrium pH (pH e ) of 6 and equilibrium time of 2 hour. The effectiveness of reduced TSS was about of 91.9% and 98.1%. Beside that, the colour intensity of color was decreased about 96.7% and 97.8% for the EDB-M and EDB-MH, respectively.