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Kapok fiber has been known for its hydrophobic-oleophilic characteristics and exhibits a great potential as oil sorbent. Methods in enhancing its hydrophobicity have been explored to improve its sorption performance in oil-in-water applications. This study investigates the oil sorption performance and hydrophobicity of kapok fibers coated with calcium stearate, a known waterproofing agent. The calcium stearate solution was prepared by mixing known amounts of stearic acid and calcium chloride in an ethanol solution. This was followed by hydrolysis using 0.12 M sodium hydroxide solution. The calcium stearate-coated kapok fibers exhibited higher hydrophobicity compared to raw kapok fibers with a water contact angle of ~137°. It achieved the highest oil sorption capacity and reusability of 50 g/g and 65% for viscous motor oil, respectively.

The present work investigated the treatment of ballast water via electrochemical disinfection using a RuO2-TiO2/Ti electrode. Batch tests were conducted with simulated ballast water containing Escherichia coli as an indicator organism. The effect of varying NaCl concentrations (1%, 2%, and 3%; w/v) and current densities (0.3, 1.0, 2.0, and 3.0 mA/cm2) on the inactivation of E. coli was examined. Results showed higher disinfection efficiency of E. coli was obtained at higher NaCl concentration and current density. Complete inactivation of E. coli was attained within 2 and 1 min at 0.3 and 1 mA/cm2, respectively, under 3% NaCl concentration. Meanwhile, complete disinfection at 1 and 2% NaCl concentrations was observed in 6 and 2 min, respectively, using a current density of 0.3 mA/cm2. The 100% inactivation of E. coli was achieved with an energy consumption in the range of 2.8 to 2.9 Wh/m3 under the NaCl concentrations at 1 mA/cm2 and 1 min of electrolysis time. The complete disinfection attained within 1 min meets the D-2 standard (E. coli/100 mL) of ballast water under the International Maritime Organization. The values of energy consumption of the present work are lower than previous reports on the inactivation of E. coli from simulated ballast water.

The present work investigated the treatment of ballast water via electrochemical disinfection using a RuO