Huei Ruey Ong

Synthesis of Copper Nanoparticles at Room Temperature Using Hydrazine in Glycerol

Copper nanoparticles (CuNPs) have been prepared by the reduction of copper chloride in glycerol using hydrazine at ambient conditions. The reduction process takes place under vigorous stirring for 8 h. The formation of CuNPs and size were confirmed by UV/Vis analysis and TEM imaging respectively. The experiment result showed that, 7.062 mM of hydrazine solution and 0.0147 mM of Cu2+ solution were needed to synthesize narrow size monodisperseCuNPs.The presence of nanoparticle was found after an induction period of 4 h and further reaction time, complete Cu0 state nanoparticle was obtained as deep red wine colour was observed. Stability study of CuNPs showed that the nanoparticles were stable up to 4 days. The particle size of the nanoparticles have been analysed by transmission electron microscopy (TEM) and the average size of CuNPs was in the range 2 to 10 nm.

Synthesis and characterization of a CaFe2O4 catalyst for oleic acid esterification

Esterification of free fatty acid (oleic acid) with ethanol over a calcium ferrite catalyst was investigated in the present study. The calcium ferrite catalyst (CaFe2O4) was synthesized by the sol–gel method, which exhibited high catalytic activity for esterification of oleic acid. The morphology and size (500–1000 nm) of the synthesized catalyst were observed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) was used to ensure the absence of impurities. The orthorhombic structure of calcium ferrite was exposed by X-ray diffractometry (XRD). The effects of reaction variables such as catalyst loading, methanol to acid ratio, reaction time and temperature on the conversion of fatty acids were studied. The optimum conditions for the esterification process was a molar ratio of alcohol to oleic acid at 12 : 1 with 5 wt% of CaFe2O4 at 70 °C with a reaction time of 2 h. XRD patterns of the recycled catalyst evidenced that the catalyst structure was unchanged up to the 3rd cycle, which indicated the long life of the catalyst.

Effect of Palm Kernel Meal as Melamine Urea Formaldehyde Adhesive Extender for Plywood Application: Using a Fourier Transform Infrared Spectroscopy (FTIR) Study

Increased demand for wood adhesives, environmental concerns, and the uncertainty of continuing availability of petrochemicals have led to recent attention on protein-based adhesives. This study was conducted to investigate the physico-chemical interaction of palm kernel meal (PKM) with melamine urea formaldehyde (MUF) resins in adhesive formulation by using Fourier Transform Infrared (FTIR) Spectroscopy. The effect of hot press on PKM extender has been investigated by FTIR and blue shift is observed due to the hot press indicating that the functional groups (such as C=O, -OH and NH) are become more free in the samples. In the case of PKM-MUF blend bonding interactions observed where, PKM played the role as an extender. Red shift of C=O and N-H groups stretching in PKM-MUF-Wood blend is observed which suggests the interaction of these functional groups through hydrogen bonding. The results suggest that PKM extender-based MUF adhesive resins have potential application for the production of exterior plywood.

Effect of waste rubber powder as filler for plywood application

Abstract The study investigated the suitability of waste rubber powder (WRP) use as filler in adhesive formulation for plywood application. Melamine Urea Formaldehyde (MUF) was employed as resin for formulating the wood adhesive. To improve chemical properties and bonding quality of adhesive, WRP was treated by different chemicals like 20% nitric acid, 30% hydrogen peroxide and acetone solution. The treated WRP were analysed by XRD and it showed that inorganic compounds were removed and carbon was remained as major component under the treatment of 20% HNO3. The treatment improved the mechanical properties like shear strength and formaldehyde emission of plywood (high shear strength and low formaldehyde emission). The physico-chemical interaction between the wood, resin and filler was investigated using fourier transform infrared spectroscopic (FTIR) technique and the interactions among N-H of MUF and C=O of wood and WRP were identified. The morphology of wood-adhesive interface was studied by field emission scanning electron microscope (FESEM) and light microscope (LM). It showed that the penetration of adhesives and fillers through the wood pores was responsible for mechanical interlocking. Therefore, chemically treated WRP proved its potential use as filler in MUF based adhesive for making plywood.

Sulfuric disazo dye stabilized copper nanoparticle composite mixture: synthesis and characterization

A copper nanoparticle–sulfuric disazo dye (Cu–SD1) composite was synthesized using the sol–gel method. Cu–SD1 nanocomposite formation was monitored by ultraviolet-visible spectroscopy (UV-vis). The acquired experimental results suggested that 8 h of reaction is needed for the synthesis Cu0 nanoparticles. Transmission electron microcopy (TEM) and atomic force microscopy (AFM) were employed to elucidate the morphology of the Cu–SD1 nanocomposite. It was found that the diameter of particle sizes were in the range of 2–4 nm. The interaction of SD1 with copper was confirmed by Fourier transform infrared spectroscopy (FTIR). The peak shift of O–H and C–OH functional groups indicated the interaction between SD1 and copper nanoparticles. Moreover, the azo group (NN) peaks were suppressed after the formation of the nanocomposite, suggesting that a strong linkage was formed between the functional groups and the copper nanoparticles. The surface composition and chemical states of the as-synthesized copper nanoparticles were elucidated by X-ray photoelectron spectroscopy (XPS). In addition, photo-switching of the composites was elucidated in the solution state. It was found that the Cu–SD1 nanocomposite has a faster switching response compared to the parent, SD1, in a solution.

Optimization of co-culture inoculated microbial fuel cell performance using response surface methodology

Microbial fuel cells (MFCs) are considered as promising technology to achieve simultaneous wastewater treatment and electricity generation. However, operational and technological developments are still required to make it as a sustainable technology. In the present study, response surface methodology (RSM) was used to evaluate the effects of substrate concentration, co-culture composition, pH and time on the performance of co-culture (Klebsiella variicola and Pseudomonas aeruginosa) inoculated double chamber MFC. From the statistical analysis, it can be seen that the performance of MFC was not influenced by the interaction between the initial COD and time, pH and time, pH and initial COD, time and initial COD. However, the interaction between the inoculum composition and time, pH and the inoculum composition, initial COD and inoculum composition significantly influenced the performance of MFC. Based on the RSM results, best performance (power density and COD removal efficiency) was obtained when the inoculum composition, initial COD, pH and time were about 1:1, 26.690 mg/L, 7.21 and 15.50 days, respectively. The predictions from the model were in close agreement with the experimental results suggesting that the proposed model could adequately represent the actual relationships between the independent variables generating electricity and the COD removal efficiency.

Control of biodegradability in a natural fibre based nanocomposite as a function of impregnated copper nanoparticles

The properties of biodegradability or non-biodegradability are highly important for the design and application of sustainable materials. The objective of this work is to introduce a novel type of nanocomposite comprising a natural fibre reinforcing agent impregnated with copper nanoparticles, and to control the biodegradability of this sustainable material using the function of the impregnated copper nanoparticles. At room temperature, copper nanoparticles were synthesized and impregnated into palm oil fibre to improve the strength and durability of the fibre and the material properties of the composite. Fourier transform infrared spectroscopic techniques were used to characterize the prepared composites. The biodegradability (minimum to maximum boundary) of the composite was studied (using the soil burial test) as a function of the quantity of copper nanoparticles, where the tensile strength was fixed at the maximum. The property of biodegradability was also optimized with the help of response surface methodology. The biodegradability of the developed composites ranged from 26.72 to 6.51% when the concentration of impregnated copper nanoparticles was varied from 0 to 2590 μg g−1 respectively. The results indicate that copper nanoparticles can be considered as a potential biocide in composite materials and in this work for controlling the biodegradability of the material by varying the quantity of impregnated copper. The relationship between the responses and variables selected in this study has been justified by the predicted models. Moreover, the model terms have been explained and the prediction has also been performed successfully. Thus, copper nanoparticles have been successfully applied for controlling the biodegradability of the nanocomposite materials. The prepared nanocomposite materials are considered for both indoor and outdoor applications. This study is quite promising for controlling the biodegradability of advanced materials, especially when the degree of biodegradability is so important for their respective applications.