Muhazri Abd Mutalib

Incorporation of N-doped TiO2 nanorods in regenerated cellulose thin films fabricated from recycled newspaper as a green portable photocatalyst

In this work, an environmental friendly RC/N-TiO2 nanocomposite thin film was designed as a green portable photocatalyst by utilizing recycled newspaper as sustainable cellulose resource. Investigations on the influence of N-doped TiO2 nanorods incorporation on the structural and morphological properties of RC/N-TiO2 nanocomposite thin film are presented. The resulting nanocomposite thin film was characterized by FESEM, AFM, FTIR, UV-vis-NIR spectroscopy, and XPS analysis. The results suggested that there was a remarkable compatibility between cellulose and N-doped TiO2 nanorods anchored onto the surface of the RC/N-TiO2 nanocomposite thin film. Under UV and visible irradiation, the RC/N-TiO2 nanocomposite thin film showed remarkable photocatalytic activity for the degradation of methylene blue solution with degradation percentage of 96% and 78.8%, respectively. It is crucial to note that the resulting portable photocatalyst produced via an environmental and green technique in its fabrication process has good potential in the field of water and wastewater treatment application.

Regenerated cellulose membrane as bio-template for in-situ growth of visible-light driven C-modified mesoporous titania.

Visible light driven C-doped mesoporous TiO2 (C-MTiO2) nanorods have been successfully synthesized through green, low cost, and facile approach by sol-gel bio-templating method using regenerated cellulose membrane (RCM) as nanoreactor. In this study, RCM was also responsible to provide in-situ carbon sources for resultant C-MTiO2 nanorods in acidified sol at low temperatures. The composition, crystallinity, surface area, morphological structure, and optical properties of C-MTiO2 nanorods, respectively, had been characterized using FTIR, XRD, N2 adsorption/desorption, TEM, UV-vis-NIR, and XPS spectroscopy. The results suggested that the growth of C-MTiO2 nanorods was promoted by the strong interaction between the hydroxyl groups of RCMs and titanium ion. Optical and XPS analysis confirmed that carbon presence in TiO2 nanorods were responsible for band-gap narrowing, which improved the visible light absorption capability. Photocatalytic activity measurements exhibited the capability of C-MTiO2 nanorods in degradation of methyl orange in aqueous solution, with 96.6% degradation percentage under visible light irradiation.

Physicochemical characterization of cellulose nanocrystal and nanoporous self-assembled CNC membrane derived from Ceiba pentandra

This research involves the rare utilisation of the kapok fibre (Ceiba pentandra) as a raw material for the fabrication of cellulose nanocrystal (CNC) and self-assembled CNC membranes. The isolation of CNC from Ceiba pentandra began with the extraction of cellulose via the chemical alkali extraction by using 5wt% NaOH, followed by the typical acidified bleaching method and, finally, the CNC production through acid hydrolysis with 60wt% H2SO4 at the optimum time of 60min. The prepared CNC was then employed for the preparation of self-assembled membrane through the water suspension casting evaporation technique. The obtained CNC membrane was characterised in terms of its composition, crystallinity, thermal stability, as well as, structural and morphological features with the use of several techniques including FTIR, XRD, AFM, TEM, FESEM, and TGA. The FESEM and AFM analyses had illustrated the achievement of a self-assembled CNC membrane with a smooth surface and a well-distributed nano-porous structure, with the porosity of 52.82±7.79%. In addition, the findings proved that the self-assembled CNC membrane displayed good adsorption capability indicated by the recorded efficiency of 79% and 85% for 10mg/L and 5mg/L of methylene blue in an aqueous solution, respectively.

A parametric study on dual-band meander line monopole antenna for RF energy harvesting

This paper studies the dual-band monopole antenna based on meander line structure for Global System for Mobile Communications (GSM) band applications, which is also has the potential to be used for RF energy harvesting. A meander line antenna with a conductor line is investigated during the design using the Computer Simulation Tool (CST) software. The antenna is fabricated on a double-sided FR-4 printed circuit board using an etching technique. The comparison between simulation and measurement results for the return loss and radiation patterns are observed and are in good agreement. A bandwidth of 97 MHz and return loss of -19.29 dB is obtained at the first frequency band, i,e. 915 MHz, while a bandwidth of 46.2 MHz with a return loss of -16.27 dB are obtained at the second frequency band, i.e. 1800 MHz. This study is an early investigation in designing the RF energy harvesting to support green technology and sustainable development particularly for Wireless Sensor Network (WSN) as well as Radio Frequency Identification (RFID) applications.

The influence of PEEK as a pore former on the microstructure of brush-painted LSCF cathodes

At lower operation temperature of intermediate temperature solid oxide fuel cells (IT-SOFC), polarization resistance was recognized as a limiting step because polarization at cathode is dependent on the rate of oxygen reduction reaction. The enhancement of cathode microstructure is one of the effective ways to improve the reaction rate. Pore former addition method is proven to be able to tailor the microstructure of cathode. The addition of polyether ether ketone (PEEK) as pore former was evaluated and compared with common pore formers (corn starch and graphite) for the microstructure cathode layer. Brush painting technique was used to deposit cathode layer on anode/electrolyte dual layer support hollow fiber. X-ray diffraction (XRD) analysis had proven that the resulting layer was free from impurities after the sintering treatment. Corn starch was able to induced cathode layer with coarse and large interconnected pores for efficient gas diffusion, as was proven by the SEM analysis. Additionally, SEM analysis also showed the formation of fine micropores throughout the layer when graphite was used as the pore former that can provide the increase in triple phase boundary region (TPB) in the layer. PEEK was able to generate both high porosity for oxygen diffusion to the reactive sites and increased number of TPB by the formation of fine microstructure pores in the cathode layer.

Pore size measurements and distribution for ceramic membranes

This chapter discusses various methods in characterizing porous ceramic membranes. The fundamental theory and calculation for every approach are given to relate the basic concept of each technique to the results obtained from experiments. A number of techniques are discussed, including gas adsorption/desorption isotherm, permporometry, mercury porosimetry, thermoporometry, bubble point method, and liquid displacement technique. This chapter includes some step-by-step methodologies in obtaining the results of pore properties for ceramic membranes. The view and comparisons that include the advantages and limitations are given in the end of this chapter.