Solid State Phenomena Vol. 317

Abstract: Here, we report the synthesis of silver nanoparticles-reduced graphene oxide (AgNPs-rGO) hybrid for simple and eco-friendly method. Silver nanoparticles (AgNPs) were successfully deposited on reduced graphene oxide (rGO) sheets to form (AgNPs-rGO) hybrid using lemon extract as a reducing and stabilizing agent. The products form a stable aqueous solution without any surfactant stabilizers and this makes it possible to produce (AgNPs-rGO) hybrid on a large scale using low-cost solution processing technique. The synthesis of nanohybrid was examed at different ratio of reducing agent (1:1, 1:2, 1:4) and characterized using UV-Visible (UV-Vis) absorption spectrum, X-ray diffraction (XRD), Raman spectroscopy analyses and transmission electron microscopy (TEM) analyses. From UV-Vis absorption spectrum, the (AgNPs-rGO) (1:1) hybrid result shows the sharp peak at 433 nm indicating the accomplishment formation of AgNPs on the surface of rGO sheets. Crystalline and spherical AgNPs with an average particle size of 21 nm were found in the (AgNPs-rGO) hybrid with the assistance of 1:1 reducing agent. Furthermore, (AgNPs-rGO) (1:1) hybrid exhibit fast electron-transfer kinetics for electrochemical reaction of Fe (CN)₆^3-/4- redox couple compared to other controlled modified electrodes, suggesting the potential applications for electrocatalysis and electrochemical sensor.

Abstract: Chitosan-hydroxyapatite composite doped with strontium was synthesised via in situ co-precipitation method. Physicochemical properties of the composite obtained were analysed using X-ray diffraction (XRD), infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX) and Thermogravimetry with differential thermal analysis (DT-TGA). The synthesized composite was subjected to bioactivity studies in simulated body fluid (SBF). The calcium release from the sample in SBF was measured using atomic absorption spectroscopy (AAS). The physicochemical properties and bioactivity of the novel composite was compared with that of hydroxyapatite, strontium doped hydroxyapatite and chitosan hydroxyapatite. The in vitro bioactivity studies of the novel composite showed that it has a higher release of Ca²⁺ in the SBF compared to the other samples. The novel material was also found to induce more Ca²⁺ deposition after 28 days of immersion in the SBF. Hence, the novel composite material has the potential to be used as biomaterials for clinical application.

Abstract: Nickel zinc carbon nanotubes (NiZnCNT) has gained substantial interest among researchers lately due to its wide application in the field of biomedical fields. Nickel zinc (NiZn) is well known for its corrosion-resistant, microware and magnetic properties. On the other hand, carbon nanotube (CNT) is known for its application as biosensor and tissue engineering scaffolds. Despite the excellent properties and diverse applications, the toxicity profile of NiZnCNT remains poorly understood. In this study, the potential toxic effect of NiZnCNT to living organism was evaluated using a nematode Caenorhabditis elegans (C. elegans) model. Adult worms were exposed to NiZnCNT at 50 and 200 μg/mL, followed by the assessment of three physiological parameters, including the effect NiZnCNT on C. elegans feeding behavior, reproductive ability and the overall lifespan of the worms. No significant difference was noted between the feeding rate of worms treated with NiZnCNT at both concentrations and the control population (p>0.05). Furthermore, there was no reduction in the production of progenies in NiZnCNT-treated worms, proposing that the nanoparticles tested does not negatively affect the reproductive system of animal. The mean lifespan of worms for untreated control, 50 μg/mL and 200 μg/mL of NiZnCNT was 10.4, 9.7 and 8.9 days respectively and no significant difference was observed in statistical analysis (p>0.05). In conclusion, this study demonstrated in the context of whole organism that NiZnCNT did not possess harmful toxic effect to living system, at concentration up to 200 μg/mL. The results further support the use of this nanoparticle in the field of biomedicine.

Abstract: An antibacterial drug, ciprofloxacin (Cipro) was successfully encapsulated into Ca/Al-layered double hydroxide (CLDH) with molar ratio Ca/Al = 3:1 (R3) by anion exchange method at optimum concentration of 0.2 M Cipro. The successful intercalation was confirmed by patterns analysis of powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), elemental analysis (CHNS) and accelerated surface area and porosity (ASAP) analysis. Basal spacing of CLDH synthesized in this study is 8.7 Å. Due to the inclusion of Cipro into the layered CLDH, basal spacing expanded to 16.2 Å in Ca/Al-Cipro-LDH (CCLDH) compare to in CLDH. The FTIR spectra of the hybrid nanocomposite show resemblance peaks of the layered double hydroxide (LDH) and Cipro, indicating the inclusion of the drug anion into the LDH interlamellae. The percentage loading of Cipro calculated from the data obtained from CHNS is 75.9% (w/w). This shows that Ca/Al-layered double hydroxide, CLDH has prospective application as the host for ciprofloxacin (1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid), an antibacterial drug for a novel drug delivery formulation.

Abstract: There are increasing intrest in research on corn based bioplastic to replace current plastic. However, corn based bioplastic faces a major drawback which are lack water barrier and poor mechanical properties resulting from its hydophilic properties. To produce better corn based bioplastic properties, a lot of research has been focuses on blend corn based bioplastic with other co biopolymer or additives and also radiation. By using radiation corn based bioplastic will induce degradation, cross linking or grafting and next the properties of corn based bioplastic will be improve in aspect of mechanical, physical and barrier properties and also acceptable to use as packaging material. Irradiated corn based bioplastic also have wide range of technology, the availability, less harmful to environment and the most important is the potential to use as packaging material. There is hot debate about using irradiated corn based bioplastic as packaging material. This review paper will be discussing and also to provide information on influence of radiation on the properties corn based bioplastic and its feasibility as packaging material.

Abstract: Carbide lime is a result of acetylene production. Carbide lime made out of calcium hydroxide with minor amount of calcium carbonate. In this study, carbide lime was used as the raw material to synthesize a new base catalyst with high base strength. A strong base catalyst was prepared through calcination and impregnation with potassium fluoride. The structure and morphology of catalyst were investigated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) The base strength was determined by Hammett Indicator test, temperature-programmed desorption of carbon dioxide (TPD-CO₂). The surface area of the catalyst was determined by Brunauer-Emmet-Teller isotherm (BET). The catalytic performance was examined through transesterification reaction. Fatty acid methyl ester (FAME) was successfully synthesized with the presence of carbide lime derived catalyst. The highest biodiesel conversion rate for sunflower oil was 95.83% with 6 wt% of catalyst loading while palm oil was 88.07% with 3 wt% of catalyst loading. The presence of the ester functional group was determined by Fourier Transform Infrared Spectroscopy (FTIR) analysis.

Abstract: Inappropriate treatments of discharge wastewater from textile industries effluents with high concentrated dye are dangerous to the human and aquatic life due to the carcinogenic effect and chemical toxicity. Therefore, the usage of TiO₂ photocatalysis in water treatment has shown a significant impact on the degradation of dye into less carcinogenic and toxicity of the water. Interestingly, the addition of graphene oxide into TiO₂ system showed better photocatalytic efficiency of dye degradation as compared toTiO₂ photocatalyst alone due to a sufficient amount of radicals supply by the graphene oxide. The oxide radicals reacted with the dye radicals and eliminate the possibility of any chances of recombination of photons and electrons during the photodegradation process. These immobilized graphene/TiO₂ films were coated onto the glass substrate under the influence of polymeric polyvinyl aceatate/ polyvinyl chloride (PVA/PVC) mixture act as a binder. The adhesion strength of the immobilized system was fixed at ratio 1:0.025 of PVA/PVC binders. As a result, the immobilized system showed a high degradation rate of methylene blue dye due to the improvement of charge separation and also good adhesion property and sustainability of the film during continuous wastewater treatment.

Abstract: A simple, low cost and rapid analytical method for determination of HCl concentration after being treated with cellulose and cellulose nanofibers (CNF) is developed. This method is based on color intensity after the HCl solution is doped with sodium iodide (NaI). The color of HCl solution changes from colorless to yellow. The intensity of the color is measured by UV – Visible spectroscopy. The UV-Visible spectra of 0.15 M HCl treated with cellulose and cellulose nanofibers is reduced from its initial concentration. The CNF absorption capacity is higher as compared to cellulose. FT-IR analysis showed that there is interaction between C-H group from the CNF backboned and chloride ion from HCl solution.

Abstract: The present study was conducted to establish adsorbent potential of magnetite nanoparticle ferrous ferric oxide (Fe₃O₄) for removal of Cu(ll) ions in wastewater. In the study, Fe₃O₄ was prepared by synthesizing low-cost recycled mill scale waste in an aqueous solution. Samples of scale wastes were milled and ground using high-energy ball milling (HEBM) at three milling times of 5, 7 and 9 hours. Extraction of Fe₃O₄ was accomplished by magnetic separation technique (MST) and Curie temperature separation technique (CTST). The morphologies and structural properties of Fe₃O₄ were characterized by using X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and Fourier-transform infrared spectroscopy (FTIR). HRTEM yielded images in the range of 10-22 nm. Maximum adsorption capacity, q_e, and percentage removal of Cu(II) ions were achieved at 4.45 mg/g and 62.61% respectively after 7 hours of milling time. The present study recorded the smallest particle size of Fe₃O₄ imparting high qe, and percentage removal of Cu (II) ion in an aqueous solution, suggesting its high adsorbent potential.

Abstract: Plant-based coagulants have been used as an alternative material to replace chemical coagulant in wastewater treatment. So far, limited information was found on the incorporation of plant-based biocoagulant to natural polymers and the effect of particle size upon wastewater treatment application. Thus, this study was conducted to explore the effectiveness of micronsized and nanosized Carica Papaya (CP) seed modified pullulan as biocoagulant. Biocoagulant were prepared at different composition of CP to pullulan, with the CP content range from 1% to 9%. The biocoagulant were characterized via Particle Size Analyzer (PSA), Fourier Transform Infrared Spectroscopy (FTIR) and morphological analysis via Field Emission Scanning Electron Microscopy (FESEM). It was used to treat municipal wastewater. The treated wastewater quality was analyzed by jar test method with dosage of biocoagulant used was 0.6g/L. Result showed that the 10% (D10), 50% (D50) and 90% (D90) distribution of micronsized CP had particle size of 0.3675 µm, 0.8433 µm and 1.9537 µm respectively. The nanosized CP was 0.4473nm (D10), 2.3758nm (D50) and 2.9938nm (D90). Characterization of biocoagulant via FTIR revealed the appearance of O-H, C=O, C-H and C-O-C bond which contribute to particle interaction for turbidity reduction of wastewater. Jar test analysis found that at 3% micronsized CP and 7% nanosized CP were able to reduce turbidity up to 59.65% and 65.27% respectively. Both size of biocoagulant slightly changed the pH of treated wastewater to neutral, increased in dissolved oxygen (DO) and reduced in total suspended solid (TSS). Overall, nanosized CP was found more effective as compared to micronsized CP.