Tannin was successfully extracted from Gelam bark using acetone as the solvent as natural alternatives. The extracted tannin was then used as corrosion inhibitor for mild steel under acidic medium. The gravimetric and electrochemical potentiodynamic corrosion tests were executed at different purified and unpurified tannin concentrations (200-800 ppm) to test the ability to inhibit mild steel corrosion. The results showed that the corrosion rate decreased as tannin concentration increased while the inhibition efficiency increased. The isotherm adsorption found that the Langmuir model was the best model to represent the interaction of tannin inhibitor and the active sites on mild steel surface. The SEM analysis showed that the mild steel morphology changed after the addition of tannin. The presence of blue-black color on the mild steel surface indicated the formation of ferric tannate to protect the surface of mild steel. In conclusion, purified tannin was a better inhibitor compared to unpurified tannin on mild steel in 1 M HCl. � 2018, Malaysian Society of Analytical Sciences. All rights reserved.

Absorption is one of the effective, simple and economical methods to remove oil from oily wastewater. The most widely used approach is to utilize lignocellulosic biomass as oil absorbent. However, the hygroscopic of cellulose have limited the oil-water separation capability of lignocellulosic fibers. In this study, the surface functionality of oil palm empty fruit bunch (EFB) fibers was slightly altered by grafting reduced graphene oxide (rGO). The modified EFB fibers show a distinct morphological and chemical characteristics changes as the surface of fibers has been coated with rGO. This was supported by FTIR analysis with the diminishing peak of hydroxyl group region of EFB fibers. While the surface modification on EFB fibers shows a diminution of a hydrophilic characteristic of 131.6% water absorption in comparison with 268.9% of untreated EFB fibers. Moreover, modified fibers demonstrated an oil-water separation increment as well, as it shows 89% of oil uptake and improved ~17 times of oil selectivity in oil-water emulsion than untreated EFB fibers.

Regenerated kenaf cellulose membranes were prepared by dissolving cellulose in a cellulose solvent of sodium hydroxide and urea, followed by coagulating in a sulfuric acid (H2SO4) solution. Different coagulant concentrations and coagulation reaction times were applied to study the morphology, physical and mechanical properties of the prepared cellulose membrane. The crystallinity index, surface morphology, mechanical performance and transparency of cellulose membrane were evaluated using X-ray diffraction (XRD), variable pressure scanning electron microscopy (VPSEM), tensile tests and UV-visible spectroscopy (UV-Vis), respectively. The results revealed changes in the pore size of the cellulose membranes, which were correlated with the concentration of sulfuric acid coagulant. However, the pore size of the membranes was not significantly affected by the coagulation time. Cellulose membranes that had been coagulated in lower concentration sulfuric acid with moderate coagulation time showed desirable mechanical properties. Thus, this study reports a favorable reaction time and coagulant concentration to fabricate regenerated cellulose membranes with desired physical properties. � 2018 Editura Academiei Romane. All rights reserved.