Preparation and photocatalytic activity of mixed phase anatase/rutile TiO2 nanoparticles for phenol degradation

The evolution of desirable physico-chemical properties in high performance photocatalyst materials involves steps that must be carefully designed, controlled, and optimized. This study investigated the role of key parameter in the preparation and photocatalytic activity analysis of the mixed phase of anatase/rutile TiO2 nanoparticles, prepared via sol-gel method containing titanium-n-butoxide Ti(OBu)4 as a precursor material, nitric acid as catalyst, and isopropanol as solvent. The prepared TiO2 nanoparticles were characterized by means of XRD, SEM, and BET analyses, and UV-Vis-NIR spectroscopy. The results indicated that the calcination temperature play an important role in the physico-chemical properties and photocatalytic activity of the resulting TiO2 nanoparticles. Different calcination temperatures would result in different composition of anatase and rutile. The photocatalytic activity of the prepared mixed phase of anatase/rutile TiO2 nanoparticles was measured by photodegradation of 50 ppm phenol in an aqueous solution. The commercial anatase from Sigma-Aldrich and Degussa P25 were used for comparison purpose. The mixed phase of anatase/rutile TiO2 nanoparticles (consists of 38.3% anatase and 61.7% rutile) that was prepared at 400°C exhibited the highest photocatalytic activity of 84.88% degradation of phenol. The result was comparable with photocatalytic activity demonstrated by Degussa P25 by 1.54% difference in phenol degradation. The results also suggested that the mixed phase of anatase/rutile TiO2 nanoparticles is a promising candidate for the phenol degradation process. The high performance of photocatalyst materials may be obtained by adopting a judicious combination of anatase/rutile and optimized calcination conditions

Carbon membrane for gas separation: a short review

For the past 30 years, membrane technology has been prominently used for various gas purifications to obtain a high purity gas. Membrane acts as semipermeable wall, which the separation occurs by controlling the rate of movement of various molecules between two liquid phases or two gas phases or a liquid and a gas phase that passing through the membranes. Then, the advantages offered by membrane process such as simple operation with low energy consumption, low operating and capital cost, continuous process and unnecessary regeneration process compared to absorption and adsorption processes, have attracted considerable attentions by researchers. Besides, traditional methods such as pressure swing adsorption, cryogenic distillation and amine absorption which experienced with high energy consumption, expensive and lead to adverse impact on the environment has even made membrane process as preferable method for gas separation. Polymeric materials were used to develop a membrane that can attain high selectivity and permeability with high chemical and thermal resistance

Measurement of neutron flux at thermal column using gold foil activation analysis and TLD detector: technical review

The thermal column at the TRIGA PUSPATI (RTP) research reactor can produce thermal neutron. However, the optimization on the thermal neutron flux produced should be performed to gain a sufficient thermal neutron for boron neutron capture therapy purpose. Thus, the objective of this review is to optimize the thermal neutron flux by designing the collimator with different materials at the thermal column. In order to fulfil the requirement, set by the IAEA standard, the study of Boron Neutron Capture Therapy (BNCT) around the world was being reviewed to study the suitable measurement, material, design, and modification for BNCT at the thermal column of TRIGA MARK-II, Malaysia. Initially, the BNCT mechanisms and history was review. Then, this paper review on the design and modifications for BNCT purpose around the world. Based on this review, suitable material and design can be used for the BNCT in Malaysia. Moreover, this paper also reviews the current status of BNCT at the RTP with the measurement of the thermal neutron flux was conducted along the thermal column at 250 kW. The thermal column of RTP was divided into 3 phases (Phase 1, Phase 2 and Phase 3) so that an accurate measurement can be obtained by using gold foil activation method. This value was used as a benchmark for the neutron flux produced from the thermal column. The reviewed demonstrated that the final thermal neutron flux produced was significantly for BNCT purpos

Zeolite templated carbon: preparation, characterization and performance as filler material in co-polyimide membranes for CO2/CH4 separation

Zeolite templated carbon (ZTC), a structurally unique carbon material was used as new fillers for the preparation of composite polymeric membrane derived from BTDA-TDI/MDI (P84) co-polyimide. The thermal stability of membrane, the structure evolution, morphology and topology, as well as gas separation performance of modified membranes were investigated. Zeolite-Y, a hard template for ZTC, was synthesized via hydrothermal method. The ZTC was synthesized via impregnation of sucrose as carbon precursor into zeolite pore and followed by carbonization at 800°C. The zeolite template was removed through acid treatment to obtain ZTC, which was used as fillers for membrane preparation. The membrane was prepared using P84 co-polyimide as membrane precursor via phase inversion process. Synthesized materials were characterized using SEM, XRD, N2 adsorption-desorption isotherm and TEM. The thermal stability of membrane was improved by the addition of ZTC. As the result of ZTC loading into P84 co-polyimide membrane, the gas permeability of CO2 increased thirty-four times, as well as the CO2/CH4 selectivity boosted from 0.76 to 5.23. The ordered pore structure in ZTC plays important role in increasing the permeability and selectivity performances of the P84 co-polyimide membrane

The development of quick response manufacturing in supply chains activities based on product planning control

The research of Quick Response Manufacturing (QRM) in the production supply chain activities of an organization are based on product planning control. A supply chain with a poor flow for instance in the company's logistics could cause the performance of the company. Inadequate preparation will result in mediocre quality, a loss of productivity and inefficiency. The objective of this thesis is to enhance the critical supply chain of a selected production line in the company by analyzing the existing data. From there, a simulation using software which is WITNESS, is conducted. The output from the simulation will be used in determining methods or solutions to enhance the supply chain related issues. The methods or solutions will be resulting in better efficiency, quality, and productivity. The data collected from the improvement will then be compared to the existing data to gauge whether the improvement contributes to the increase in efficiency and productivity of the selected line. The results from the simulation appear positive feedback, with an average of 85% of the busy time on the proposed layout simulation compared to 66% on the current layout. Even though the differences are minor, they can be critical during peak hours. Finally, the result obtained between the current layout and improved layout proves that the implementation of Quick Response Manufacturing (QRM) can increase the productivity of Dunham Bush company at Kajang, Selangor

Structural characterization of N-doped anatase-rutile mixed phase TiO2 nanorods assembled microspheres synthesized by simple sol-gel method

In this study, N-doped anatase–rutile mixed phase TiO2 nanorods assembled microspheres were synthesized via a direct and simple sol–gel method. The physical analysis via X-ray diffraction indicated that the prepared sample had a mixed phase of anatase and rutile TiO2. The morphology of the structure was observed with field emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy, which showed that the formation of TiO2 microspheres was constructed by TiO2 nanorods or rice like structure nanorods. Besides, Fourier transform infrared analysis revealed that the presence of N2O2 2- and NO- species in the spectra while XPS study indicated the incorporation of nitrogen as dopant in TiO2 at binding energies of 396.8, 397.5, 398.7, and 399.8 eV. Furthermore, the optical properties determined by UV–Vis spectroscopy concluded that the prepared sample exhibited excellent optical responses to UV and visible region as well as being a potential material for degradation of hazardous water pollutants. The photocatalytic activity of the prepared TiO2 exhibits excellent photodegradation of methylene blue under UV and visible light irradiation

Effect of P84 (BTDA-TDI/MDI) composition towards the performance of the disk supported carbon membrane

Carbon membrane has attracted researchers’ attention as it is superior in terms of its gas separation performance. In this study, the composition of polymer precursor in the dope solution was investigated based on carbon membrane performance. P84 polyimide was chosen as the polymer precursor as it fulfils the requirement for carbon membrane properties. By varying the polymer precursor composition (6, 9, 12, and 15 wt.%), P84 was stirred in NMP solvent until homogenous solution was formed. Commercialised alumina disc was coated via spray coating method at 1 bar at room temperature. The disc supported polymeric membrane was carbonised at 700 °C under nitrogen (200 ml/min) with heating rate of 3 °C/min. The carbon membrane was analysed via SEM. Gas permeation tests were performed using pure O2 and N2 at 4 bar at room temperature. The selectivity of 3.7 was obtained using the disc supported carbon membrane for O2/N2. The optimum polymer composition in this study was obtained by 12 wt.% of P84

FTIR analysis of plant-based cellulose as adsorbents for water remediation

Finding an effective, green adsorbent for removal of heavy metals is one of the main problems in water purification field. Cellulose has gain tremendous attention for its variability of purposes including heavy metal removal via adsorption. As a preliminary material study, Fourier Transform Infrared Spectroscopy (FTIR) would be a good step in analyzing the removal potential of an adsorbent. In this study, cellulose-based adsorbent extracted from Pandan leaves was subjected to acid hydrolysis after being pre-treated with alkali and bleaching treatment. The output material was then analyzed in this research using FTIR. The result showed that some components were removed after the treatments and the material has potential for future development as adsorbent for heavy metal removal due to presence of carboxyl group in the backbone

PVDF/Fe2O3 mixed matrix membrane for oily wastewater treatment

Oily wastewater has been recognized as one of the most concerned environmental pollutions that come from a variety of sources. The increasing of these uncontrollable oily wastewater discharges consequently leads to environmental problems. The current barrier in this situation is when dealing with finely emulsified oily wastewater streams with small droplet size (< 20 μm in diameter). To tackle this issue, it is found that the utilization of the membrane technology is most effective due to its highly effective separation process and simplicity. Nevertheless, traditional filtration membranes are mostly afflicted with low flux and rejection rate as a consequence of easy fouling caused by the plugging of oil and surfactant. Thus, the wettability and antifouling properties of the membrane play an important role in dealing with this issue. The aim of this study was to evaluate the performance and operation of the membrane when treating oily wastewater. PVDF was chosen as the host polymer based on its outstanding properties and 0.2 wt% of Fe2O3 loading was utilized to enhance the hydrophilicity of the membrane. The effects of mixed matrix membrane (MMM) and neat poly (vinylidene fluoride) (PVDF) membrane relating to their differences in the SEM images, water flux and oil rejection were studied. The presence of additive in the polymeric composition has helped to achieve 40% higher flux increment with an oil removal efficacy of ~97 %, as compared to the unmodified PVDF membrane

Reformed polyimide/nanocrytalline cellulose for gas separation

Manufactured via single step coating-carbonization cycle to reduce production time and cost. Excellent thermal resistance and chemical stability. Perfect product for wide range of gas separation applications. Present various carbonization condition for supported carbon membrane