Junaidah Jai

Plant Extract as Reducing Agent in Synthesis of Metallic Nanoparticles: A Review

The aim of this paper is to discuss on the roles of plant extract in the synthesis of metallic nanoparticles. Synthesis of metallic nanoparticles has started few decades ago through physical and chemical methods. Recently, green technology through biosynthesis method has drawn great attention compared to the physical and chemical method. Biosynthesis was found to be more energy efficient and able to eliminate the use of hazardous chemicals. The biosynthesis studies involved the application of fungi, bacteria, yeast, algae and plant extract. Plant extract has several advantages since the use of microorganism required stringent control on cell culture. Furthermore, the reaction rate is much faster as compared to that of the microorganism methods. The important compounds in the plant extract are hydroxyl and carbonyl groups. Both functional groups allowed plant extract to act as reducing agent as well as stabilizing agent. Several studies have been carried out to optimize the extraction of these compounds such as plant drying technique, extraction temperature and type of extractions solvent. The common method used to quantify the concentration of reducing agents in the extract is through Folin-Ciocalteu method. Utilization of plant extract not only capable of producing well dispersed monometallic nanoparticles, but also bimetallic nanoparticles. Previous studies revealed that concentration of plant extract has significant effect on particle size and shape as well as particle distribution.

Interaction between Binder and Powder in Injection Moulding of 316L Stainless Steel

Owing to several steps involved in metal injection moulding (MIM) process, it is important to understand the interactions between metal powder and binder mixture particularly during mixing, injection moulding and debinding. A polar organic compound generally forms hydrogen bonds more readily with metal powder because of acid-base interactions. In this study, the interaction of local binder system comprised of; palm stearin (PS) and thermoplastic natural rubber (TPNR) with conventional binder; polyethylene (PE), polypropylene (PP) and paraffin wax (PW) and mixed with 316L stainless steel powder were investigated. The results showed that all the binder have high interaction with 316L stainless steel that make, the resulting the bonding sufficiently strong and suitable for MIM process. Keywords: Chemical interaction, Injection Moulding, Binder, Rheology

Preparation, characterization and effectivity of N, Fe-TiO2 as a visible light active photocatalyst

Surface modification of the titanium dioxide by doping and co-doping with nitrogen and iron in order to make the photocatalyst active under visible light was investigated. Solgel method was adapted for the preparation of surface modified titanium dioxide, where tetra titanium isopropoxide, ammonium nitrate and ferric nitrate were used as precursors while maintaining the dopant concentration and calcination temperature at 0.75% and 600°C, respectively. The prepared photocatalyst samples were characterized by XRD, FE-SEM and FTIR in order to study their physical properties. The results from XRD confirmed that all prepared photocatalyst were of anatase phase. FE-SEM image analysis revealed the formation of fine particles and the FTIR analysis verified the presence of dopants. The effectivity of photocatalysts was tested by performing a standard batch photocatalytic degradation experiment with methylene blue as a model pollutant under visible light. The result showed that co-doped photocatalyst (0.75% N, 075% Fe-TiO2-600) yielded a maximum of 76% methylene blue degraded within three hours of irradiation time.

Comparative Inhibition Effect of Synthesized Fatty Amides Mixture, Pyridine and Pyrrole on Carbon Steel in Saline Environment

The inhibition effect of synthesized fatty amides mixture, pyridine and pyrrole as corrosion inhibitors on carbon steels in saline water had been compared using Linear Polarization Resistance Method (LPRM). It is still unknown which of these organics performed best than another. The experimental results showed that the inhibition effect of the synthesized fatty amides mixture is found to be better than pyridine and pyrrole, indicating the presence of various chain lengths of fatty amides molecules. These molecules provide a better surface on carbon steels than pyrrole and pyridine.

Effect of Coating Adhesion on Turmeric Essential Oil Incorporated into Chitosan-Based Edible Coating

The main objective of this paper is to study the coating adhesion of edible coating incorporated with active ingredients from turmeric essential oil on cherry tomatoes. The effects of different concentrations (20, 10, 5, 2.5, 1.25, and 0.75 μL) of turmeric essential oil into chitosan-based edible coating were evaluated. The sessile drop technique was applied to measure the contact angles on the surface of the tomatoes. The critical surface tension of the tomato was 18.36 mN/m, and its polar and dispersive component was 3.55 mN/m and 27.31 mN/m. The surface tension of the tomato was found to be 30.86 mN/m. All these surface tension were obtained from the Zisman plot method.

Modification of PdO/CeZrO2 doped with transition metals (Y and Fe) for reducibility properties

This paper describes the synthesis of modified nanocatalysts of PdO/CeZrYO2(PdO/CZY), PdO/CeZrFeO2(PdO/CZF) and PdO/CeZrO2(PdO/CZ) via microemulsion followed by deposition – precipitation method. The structural, textural and redox properties of the synthesized nanocatalysts were investigated. The diffractogram of XRD showed that all the synthesized nanocatalysts indicate a symmetrical pattern of cubic phase crystallinity. The amount of PdO was detected using EDX analysis and PdO/CZF portrayed the highest Pd contents of about 4.63 %. Therefore it shows a good potential to have reducibility properties and can be manifested active at low temperature reduction.

Kinetic formation of silver-copper nanoparticles and its characterization

A study of the kinetic formation of silver-copper nanoparticles in aqueous medium on the basis of size distribution and its characterization has been carried out and reported in this paper. The Ag-Cu nanoparticles were synthesized through polyol method that using Ethylene Glycol (H2C6O12) as a reduction agent and solvent and Polyoxyethylene-(80)-Sorbitan Monooleate (Tween 80) as a stabilizer. The kinetic formation of Ag-Cu nanoparticles was observed using Dynamic Light Scattering (DLS) and characterized by using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscope (TEM). The XRD analysis results confirmed that size distribution was strongly dependent on molarity of precursors of silver (AgNO3) and copper (Cu(NO3)2.3H2O). The FESEM and TEM analysis indicated the existence of Ag and Cu nanoparticles in the core-shell shape. The silver-copper nanoparticles were spherical and uniform particles size with the average size of about 28 nm and 38 nm for ...

Kinetic Mechanism on Synthesis of Copper Nanoparticle from Reduction Reaction - Effect of Temperature

Copper nanoparticles, due to their interesting properties, low cost preparation and many potential applications in catalysis, cooling fluid or conductive inks, have attracted a lot of interest in recent years. In this study, copper nanoparticles were synthesized through the palm leaves extract that act as reducing agent. In this synthesis route, the hydroxyl groups of the polyphenols in palm extract are capable to act as reducing agent for reduction reaction. The effect of temperature given starting with control parameters at room temperature proceeds to 40, 50, 60, 70 and 80°C with the time length of 2 hours and 10 milimol copper nitrate aqueous solution. Characterization had been conducted using the instrument of UV-vis spectrophotometer, FTIR and ESEM. The average size of all powder nanoparticles was found to 109, 86, 196, 133, 241, and 230nm accordingly from room temperature till 80°C. The correspondence analysis of the results yielded that the optimum temperature was at 40°C which is 86nm of average copper nanoparticle size.

Surface morphology study: Effect of electrolyte pH on the electrodeposited Sn-Ag-Cu(SAC) solder alloy

pH control is significant in electrodeposition because they affect the characteristics of electrolyte and the deposit. This paper mainly analyses the processing conditions of electrolyte pH value on the electrodeposited SAC. Sn2+ ions will be obtained from the tin methane sulphonate acid while the Cu2+ and Ag+ ions will be obtained from their respective sulfate salts. Ammonium acetate helps in raising the pH of the bath. The FESEM analysis was carried out to examine the morphology of the electrodeposited nanocomposites. A variety of morphological patterns for the electrodeposits with different electrolyte pH is obtained. At low pH (2) electrolyte value, the electrodeposits show a very poor quality with rough surface. With increasing pH value (2.5), the averaged grain sizes decreased. The surfaces of the films electrodeposited at this pH value are generally quite smooth, uniform and compact. Later increment of pH values (3~4) has lead to the formation of porous and non-uniform electrodeposits. From the study, it is possible to observe that, even with the same composition, the deposits have different morphologies under different controlled parameter.

Green Synthesis of Silver Nanoparticles Using Elaeis guineensis (Palm Leaves): An Investigation on the Effect of Reaction Time in Reduction Mechanism and Particle Size

In this research, green synthesis of silver nanoparticles using elaeis guineensis leaves extract was investigated and the effect of reaction time in reduction mechanism and particle size is studied. UV-visible sprectrophotometer was used to monitored the reduction reaction of silver ions to silver nanoparticles and formation of silver nanoparticles shown at 15 minutes. Transmission electron microscopy (TEM) and field emission scanning electron microcopy (FESEM) shows polydispersed and irregular shape of silver nanoparticles with aggregation. Further confirms the formation of silver nanoparticles by energy dispersive x-ray analysis (EDAX). From this research, it was found that the increasing reaction time increases the rate of reduction reaction of silver ions.