Papers by Keyword: Physico-Chemical Properties

Abstract: Clove oil is a volatile oil that is extracted from clove buds of Syzygium aromaticum. It was reported for antibacterial and antifungal activities. Microemulsions (ME) are a stable emulsion system composed of oil, surfactant mixture (SM, surfactant and co-surfactant) and water. In this study clove oil-loaded microemulsions (CM) were fabricated using Tween 20 as surfactant. Co-surfactants used in CM were ethanol and isopropanol. CM with different concentrations of clove oil (10-50% w/w) and SM (40-80% w/w) at Tween 20:co-surfactant ratios of 1:2 were formulated and characterized for their physico-chemical properties. All CM was clear liquid with thermodynamic stability. The size of all CM prepared from both ethanol and isopropanol was less than 100 nm. At lower oil and SM concentrations, the CM was o/w ME. When the concentration of oil or SM increased, the conductivity values decreased to less than 10 μS/cm indicating that the obtained CM was w/o ME. All CM formulations exhibited strong antioxidant activity as tested by the DPPH scavenging method (92.79 - 94.95% inhibition). Changing the type of co-surfactants (ethanol or isopropanol) or changing the oil to co-surfactant ratio did not significantly alter the antioxidant activity. Therefore, considering both physicochemical properties and antioxidant activity of CM, the CM containing 10% clove oil is the recommended formulation for commercial development.

Abstract: Study of physico-chemical properties, adsorption and desorption of Zn using citric acid and tartaric acid on the textile industrial area has been carried out. This study aims to analyze the physico-chemical character of the soil and the content of heavy metals around the textile industry which is suspected of being contaminated by waste, the adsorption isotherm and capacity of Zn, the desorption kinetics of Zn using citric acid and tartaric acid solutions. Soil samples were divided into three sample points based on the location where they were taken, namely sample points I, II and III. The physical and chemical properties of soil were measured, included pH, ash content, electrical conductivity, total organic carbon, cation exchange capacity and content of heavy metals The adsorption capacity was studied by the adsorption of Zn on the soil. Meanwhile, the desorption was studied by using both citric and tartaric acid solution. The results showed that sample I had the highest total organic carbon content of 692.3 mg g^-1, and a cation exchange capacity of 42.0 cmol⁺ kg^-1 with a metal content of 735.0 mg kg^-1. The maximum adsorption capacity of Zn is 708.7 mg kg^-1. The optimum desorption using citric acid occurs at a concentration of 0.6 mol L^-1, pH 3 and a time of 7 h, while tartaric acid occurs at a concentration of 0.8 mol L^-1, pH 3 and a time of 7 h. Keywords: citric acid, tartaric acid, physico-chemical properties, zinc

Abstract: Clove oil, extracted from dried floral buds of clove (Syzygium aromaticum), are used in topical products because it has antioxidant and antimicrobial activities. Microemulsions (ME) are stable emulsion which can be formulated by simple mixing of oil, water, surfactant and co-surfactant. The objectives of this research were to develop and evaluate clove oil-loaded ME for topical application by using Tween 80 as surfactant. Ethanol, isopropanol and propylene glycol (PG) were used as co-surfactants. Pseudo ternary-phase diagram showed that using ethanol and isopropanol provided larger ME area than using PG in all surfactant:co-surfactant ratio (SR; 1:0.5, 1:1 and 1:2). Up to 20% w/w of clove oil can be loaded in ME by using surfactant mixture of 60-80% w/w. The effects of various amounts of clove oil (5-20%) and surfactant mixture (60, 70, 80%) at SR of 1:1 on physico-chemical properties of ME were observed. All formulations are transparent with the pH values of 6.8-8.0. The droplets size of ME using ethanol and isopropanol as co-surfactant ranged from 10-100 nm while that using PG was higher. Conductivity values showed that all formulations were o/w ME. Zeta potential values revealed stable particles. For ethanol and isopropanol, ME containing 5-10% clove oil and 60-70% SM showed good physico-chemical stability. The amount of eugenol in clove oil analyzed by gas chromatographic (GC-FID) method was 82.27% v/v. The stability test of selected formulations (70% surfactant mixture at SR = 1:1) was evaluated from %eugenol remaining at room temperature and in refrigerator after 4-week storage. It was found that the amount of eugenol in the formulation was effected by the storage condition. Our results indicate that clove oil can be prepared in ME with physico-chemical stability by using Tween 80 and ethanol as surfactant system.

Abstract: The objective of this study was to apply rice bran protein hydrolysates (RBH) as bioactive additives of gelatin/Eudragit^® NE 30D film and characterize the physicochemical and mechanical properties of its. The RBH was obtained by extraction with 2% sodium chloride (RBH-NaCl) and 0.1 N sodium hydroxide (RBH-NaOH) followed by digestion with Alcalase^®. Then, RBH was incorporated in gelatin/Eudragit^® NE 30D film. Effect of RBHs on film thickness, moisture content, pH, Young's modulus, tensile strength and the elongation at break were investigated. The RBH-NaCl enriched film showed non-homogeneous mixture and reduced moisture content, tensile strength and the elongation at break (1.8 – 2 folds). However, the RBH-NaOH enriched film exhibited a few non-homogeneous mixture and the Young's modulus was slightly decreased. The pH value was increased in the range of 6.77 – 6.88. Our results provide insight for the potential to develop RBH containing films as topical products.

Abstract: The Influence of Physico-chemical properties on heavy metals contenton the Illegal Land Fill at Kadisoka, Sleman, Yogyakarta has been carried out. The aims of this research are to evaluatethe metal concentrationin the soil, analyze the physicochemical properties including water and ash contents, pH, electrical conductivity, total organic carbon, cation exchange capacity; and to find out the maximum heavy metals contentthe soil samples.Soil samples were divided into three samples based on places where they were taken in the landfill area, namely sample I, II and III. Heavy Metals content in the solution were measured by Atomic Absorption Spectrophotometer (AAS).The results showed the highest heavy metal content in soil was Zn. Sample II had the highest Zn value at 1,199 mg kg^-1, whereas sample I had the lowest total Zn content of 708.54 mg kg^-1.

Abstract: Lead-acid batteries were widely used in many industries as important power supply devices for military and civil industries, transport and shipment devices owing to its advantages of low cost,high performance and safety. According to statistics, most lead-acid batteries can reach 1-2 years life under operating conditions, generating millions of used lead-acid batteries each year in China, which caused economic and environmental losses if not properly treated. The changes of physico-chemical properties in the process of operation of lead-acid battery were summarized in this paper. The corrosion and deformation of grids, water loss in electrolyte, aging of separators, corrosion of plates and irreversible sulfation were the main physico-chemical properties changes resulting in battery failure. In the homogeneous acidic medium, the grid of the lead-acid battery corroded away, one side was dotted distribution, and the other side was interlaced net shape. The corrosion of grids and incomplete reaction may lead to the water loss in electrolyte. What’s more, there existed a series of chemical reactions that reducing the battery capacity and leading to the failure of batteries, such as the aging and elastic collision of separators and irreversible sulfation. By analyzing the physico-chemical properties changes in the process of operation, the study supplied the direction for the specification of operating conditions and the extending of service life of lead-acid battery. The basic theories were provided for the repair, regeneration and recovery of lead-acid batteries.

Abstract: This study investigated the water quality of some of the ex-mining lakes in Perak State of Malaysia for possible use as alternative to water supply and compared them to water quality of some of the rivers used for intake of water treatment. A total of twelve (12) water samples were collected for analyses from selected sampling sites. These samples were analyzed for physico-chemical properties, heavy metals concentrations, and organic pollutants concentrations. The analyzed results indicated that average temperature varied from 28.1 ^oC to 34.1 ^oC, pH 6.2 to 9.0, EC 55 to 400 μs/cm ,turbidity 5.6 to 74.2 NTU, DO 3.21 to 9.56 mg/l, TDS 36.8 to 268 mg/l, F^- 0.017 to 0.182 mg/l, Cl^- 0.483 to 3.339 mg/l, Br^- 0 to 0.392 mg/l, SO₄^2- 0.051 to 15.307 mg/l, Mg 0.833 to 1.466 mg/l, Na 0.669 to 3.668 mg/l, and Ca 2.85 to 26.77 mg/l. Heavy metals concentrations (mg/l) were: Zn 0.04 to 0.057, Pb 0.019 to 0.075, Cd not detected, Ni 0.013 to 0.105, As not detected to 0.004, and Cu not detected while COD 4 to 51 mg/l. Analyses revealed that all the water samples were turbid and containing slightly high concentration of Pb. Generally, they had common water quality problem. Further work should carry out more tests on other water quality parameters particularly on heavy metals, chemical and biological pollutants at different seasons.

Abstract: In this study, three polyurethane systems A (A450/RD181/L75), B(A450/RD181/N3390) and C(A450/RD181/2104/N3390) for in-mould decoration ink were studied. The results of thermogravimetric analysis showed that introducing rosin modified phenolic resin 2104 (RMPR) and N3390 into PU system A can improve the thermal stability, Moreover, Measurements of gel fraction and swell ratio showed that incorporation of N3390 is benificial for increasing the cross-linking density of PU systems as compared to L75 so as to increase the gel fraction and decrease the swell ratio.The tensile strength of cured PU systems increased following in the order: A

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