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Silver nanoparticles and silver-graphene oxide nanocomposites were fabricated using a rapid and green microwave irradiation synthesis method. Silver nanoparticles with narrow size distribution were formed under microwave irradiation for both samples. The silver nanoparticles were distributed randomly on the surface of graphene oxide. The Fourier transform infrared and thermogravimetry analysis results showed that the graphene oxide for the AgNP-graphene oxide (AgGO) sample was partially reduced during the in situ synthesis of silver nanoparticles. Both silver nanoparticles and AgGO nanocomposites exhibited stronger antibacterial properties against Gram-negative bacteria (Salmonella typhi and Escherichia coli) than against Gram-positive bacteria (Staphyloccocus aureus and Staphyloccocus epidermidis). The AgGO nanocomposites consisting of approximately 40 wt.% silver can achieve antibacterial performance comparable to that of neat silver nanoparticles.

Cellulose nanofibrils (CNF) were prepared from kenaf core (KC) using acidified-chlorite bleaching method and followed by disintegration using high speed blender. The effects of disintegration time and acid treatment on the defibrillation of holocellulose were studied. Hemicellulose was found to facilitate defibrillation, as CNF without any acid treatment was fully defibrillated after 30 min. The adsorption kinetics of CNF toward cationic dye cannot be accurately determined due to its quick adsorption performance, in which the equilibrium is achieved immediately after 1 min of contact time. The effects of acid treatment on holocellulose, pH, adsorbent dosage, temperature and dye concentration were studied and optimized. Adsorption data were fitted to both Langmuir and Freundlich models where Langmuir model was found to be the better model to describe the adsorption process. Maximum adsorption capacity was found to be 122.2 mg/g at pH 9, 20 °C for the non-acid treated CNF. The CNF can be regenerated by desorption at low pH where, as much as 70 % of dye adsorbed can be desorbed after 6 cycles of adsorptiondesorption cycle.

With the emerging technology in the 21st century, which requires higher electrochemical performances, metal oxide composite electrodes in particular o®er complementary properties of individual materials via the incorporation of both physical and chemical charge storage mechanism together in a single electrode. Numerous works reviewed herein have identi¯ed a wide variety of attractive metal oxide-based composite electrode material for symmetric and asymmetric electrochemical capacitors. The focus of the review is the detailed literature data and discussion regarding the electrochemical performance of various metal oxide composite electrodes fabricated from di®erent con¯gurations including binary and ternary composites. Additionally, projection of future development in hybrid capacitor coupling lithium metal oxides and carbonaceous materials are found to obtain signi¯cantly higher energy storage than currently available commercial electrochemical capacitors. This review describes the novel concept of lithium metal oxide electrode materials which are of value to researchers in developing high-energy and 1430002-1 NANO: Brief Reports and Reviews Vol. 9, No. 6 (2014) enhanced-cyclability electrochemical capacitors comparable to Li-ion batteries. In order to fully exploit the potential of metal oxide composite electrode materials, developing low cost, environment-friendly nanocomposite electrodes is certainly a research direction that should be extensively investigated in the future.

Magnetite (Fe 3 O 4 ) nanoparticles prepared using hydrothermal approach were employed to study their potential application as magnetic resonance imaging (MRI) contrast agent. The hydrothermal process involves precursors FeCl 2 Á4H 2 O and FeCl 3 with NaOH as reducing agent to initiate the precipitation of Fe 3 O 4 , followed by hydrothermal treatment to produce nano-sized Fe 3 O 4 . Chitosan (CTS) was coated onto the surface of the as-prepared Fe 3 O 4 nanoparticles to enhance its stability and biocompatible properties. The size distribution of the obtained Fe 3 O 4 nanoparticles was examined using transmission electron microscopy (TEM). The cubic inverse spinel structure of Fe 3 O 4 nanoparticles was confirmed by X-ray diffraction technique (XRD). Fourier transform infrared (FTIR) spectrum indicated the presence of the chitosan on the surface of the Fe 3 O 4 nanoparticles. The superparamagnetic behaviour of the produced Fe 3 O 4 nanoparticles at room temperature was elucidated using a vibrating sample magnetometer (VSM). From the result of custom made phantom study of magnetic resonance (MR) imaging, coated Fe 3 O 4 nanoparticles have been proved to be a promising contrast enhanced agent in MR imaging. #