Search

Due to industrial expansion (printing, rubber, plastics, textiles, cosmetics, leather industries, etc.), various types of synthetic dyes are discharged into the water bodies which cause severe hazards to the environment. Therefore, these dyes need to eliminate from the wastewater using potential adsorbent materials. Graphene-Silver oxide nanocomposite (GO-Ag) was synthesized by modified Hummer’s method using lemon juice as a reducing agent. This adsorbent was employed for malachite green (MG) removal from the aqueous solution. The chemically synthesized adsorbent was characterised using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM). The efficiency of GO-Ag nanocomposite was studied under different experimental limits such as solution concentration, time and pH. The capacity of adsorption of dye (MG) was observed to be 65.21 mg/g at pH 8. The adsorption of malachite green onto GO-Ag nanocomposite best fit to Freundlich model and followed the pseudo-second order of kinetic model. The method can be applied to dyes removal in wastewaters.

The massive production of rice straw could eventually lead to uncontrolled air pollution due to open burning activity. In this study, the rice straw was treated with alkaline hydrogen peroxide (AHP) to remove silica as well as to maximize the hydrolysis of the treated rice straw. Thus the study aimed to determine the effects of reaction parameters (i.e. AHP concentrations, particle sizes of rice straw, and temperature) towards the pretreatment with AHP in a batch system. From the characterization analysis, the rice straw sample contained high amount of silica (20%) and lignin (20%). From the study, >83.8% silica removal, 80% of delignification, and 7.88% of reduced sugar were achieved at optimum conditions of 60 °C with 10% AHP solution for sample with

This investigation reports on the biosorption mechanism of Congo Red dyes (CR) in aqueous solution using acid-treated durian peels, prepared for this study. The biosorbent nature was characterized using the Scanning Electron Microscopy (SEM), Fourier Transform infrared spectroscopy (FT-IR) and Brunaure-Emmet-Teller (BET). The effect of process parameters within operational range of pH (2–9), contact time (10–200 min), initial concentration (25–400 mg g−1) and temperature (25–65 °C) for the optimum removal of CR dyes was investigated using central composite design (CCD) under response surface methodology (RSM), and revealed that the optimum condition of biosorption was achieved around a pH of 5.5, contact time of 105 min at initial concentration of 212.5 mg L−1 within 45 °C temperature, which corresponds to 95.2% percent removal of CR. The experimental data fitted better to the second order polynomial model, with a correlation coefficient R2 value of 0.9917 and the Langmuir isotherm model with biosorption capacity of 107.52 mg g−1. Gibbs free energy indicated that the adsorption of CR dyes was spontaneous. The mechanism of the adsorption of CR dyes revealed that the biosorption of CR dyes investigated under different operational conditions show that under acidic pH, the adsorption efficiency of the acid treated durian peels is enhanced for the adsorption of CR dye molecules.

Eucalyptus globulus is an aromatic medicinal plant which known for its 1,8-cineole main pharmacological constituent exhibits as natural analgesic agent. Eucalyptus globulus-loaded micellar nanoparticle was developed via spontaneous emulsification technique and further evaluation for its analgesic efficacy study, in vivo analgesic activity assay in rats. The nanoemulsion system containing Eucalyptus-micelles was optimized at different surfactant types (Tween 40, 60 and 80) and concentrations (3.0, 6.0, 9.0, 12.0, 15.0, and 18.0 wt. %). These formulations were characterized by thermodynamically stability, viscosity, micelles particle size, pH, and morphology structure. The spontaneous emulsification technique offered a greener micelles formation in nanoemulsion system by slowly titrated of organic phase, containing Eucalyptus globulus (active compound), grape seed oil (carrier oil) and hydrophilic surfactant into aqueous phase, and continuously stirred for 30 min to form a homogeneity solution. The characterizations evaluation revealed an optimized formulation with Tween 40 surfactant type at 9.0 wt. % of surfactant concentration promoted the most thermodynamic stability, smaller micelles particle size (d = 17.13 ± 0.035 nm) formed with spherical shape morphological structure, and suitable in viscosity (≈2.3 cP) and pH value (6.57) for transdermal purpose. The in vivo analgesic activity assay of optimized emulsion showed that the transdermal administration of micellar nanoparticle of Eucalyptus globulus on fore and hind limb of rats, possessed the central and peripheral analgesic effects by prolonged the rats pain responses towards the heat stimulus after being put on top of hot plate (55 °C), with longest time responses, 40.75 s at 60 min after treatment administration. Thus, this study demonstrated that micellar nanoparticle of Eucalyptus globulus formed in nanoemulsion system could be promising as an efficient transdermal nanocarrier for the analgesic therapy alternative.

In the present work, acid treated natural oil palm trunk powder (OPTP) has been utilized as novel adsorbents for the removal of methyl orange (MO) from aqueous solution. The batch method was employed to study the adsorption behavior of MO which was subsequently determined by UV/Visible spectrophotometer. The adsorption characteristics and operational parameters were determined by monitoring different parameters such as pH, contact time, dye concentration and temperature. The acid treated OPTP and MO saturated OPTP adsorbent were characterized based on Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The maximum adsorption of MO was observed at pH 6 and a contact time 120 min was sufficient to attain the equilibrium. The adsorption of MO onto treated OPTP best fit to Langmuir model and followed the pseudo second order kinetic model. Different thermodynamic parameters such as free energy, enthalpy, and entropy have been calculated and it was concluded that with increase in temperature adsorption increases, which indicates adsorption of MO onto OPTP was endothermic in nature and favourable with positive value of .H . The method can be applied to the removal of MO dyes in waste waters.

The aim of this chapter is to review recent developments in the detection of potentially dangerous VOCs (VOCs) using various kinds of carbon-based nanocomposites. These VOCs include components of gasoline, benzene, toluene, xylene, tetrachloroethylene, etc., that have adverse effects on the health of humans as well as other living organisms. Carbon-based nanocomposites are now considered new and novel materials that provide high tensile strength as well as mechanical, electrical, and thermal properties that make them better and more promising candidates for the detection of potential hazardous VOCs. In addition, owing to the ease of fabrication and reduction, the low cost, and simple operation, carbon-based nanocomposites offer great potential for portable real-time medical diagnostics, in contrast to the conventional methods-based on cost and labor-extensive lab-bench instruments. A summary of recent information obtained using various VOCs with different carbon-based nanocomposites has been included in the discussion. Alongside the detection efficiency, their mode of operation under various parameters has been covered in detail.

Nowadays, microbially induced calcium carbonate precipitation (MICP) has received great attention for its potential in construction and geotechnical applications. This technique has been used in biocementation of sand, consolidation of soil, production of self-healing concrete or mortar, and removal of heavy metal ions from water. The products of MICP often have enhanced strength, durability, and self-healing ability. Utilization of the MICP technique can also increase sustainability, especially in the construction industry where a huge portion of the materials used is not sustainable. The presence of bacteria is essential for MICP to occur. Bacteria promote the conversion of suitable compounds into carbonate ions, change the microenvironment to favor precipitation of calcium carbonate, and act as precipitation sites for calcium carbonate crystals. Many bacteria have been discovered and tested for MICP potential. This paper reviews the bacteria used for MICP in some of the most recent studies. Bacteria that can cause MICP include ureolytic bacteria, non-ureolytic bacteria, cyanobacteria, nitrate reducing bacteria, and sulfate reducing bacteria. The most studied bacterium for MICP over the years is Sporosarcina pasteurii. Other bacteria from Bacillus species are also frequently investigated. Several factors that affect MICP performance are bacterial strain, bacterial concentration, nutrient concentration, calcium source concentration, addition of other substances, and methods to distribute bacteria. Several suggestions for future studies such as CO2 sequestration through MICP, cost reduction by using plant or animal wastes as media, and genetic modification of bacteria to enhance MICP have been put forward.

In the present research, we study the thermodynamic parameters of ternary system of two different sugars, i.e., (a)D(-)glucose+lysozyme+water and (b)maltose+lysozyme+water. It has been done at various temperatures (293.15, 303.15, 313.15 and 323.15 K) and concentrations of sugars. The apparent molal volume and apparent molal compressibilities have been calculated for these systems. The partial molal volume of D(-)glucose and maltose has also been evaluated in aqueous lysozyme solution. We have made an attempt to examine transfer volume of the said solutes from water to aqueous lysozyme solution. Interaction between sugars and water molecules is expected to create polar environment, which helps to increase the hydrophobic interactions in proteins, thus stabilizing the protein.

Dielectric properties of materials play a significant role in design of microwave assisted processing system. This paper is focused on the dielectric properties of ε-caprolactone (ε-cap) which is the monomer for the biodegradable polymer, Poly (ε-caprolactone) (PCL). The dielectric properties of ε-cap were measured across a wide range of frequencies (0.1 GHz5.0 GHz) and temperatures (20-150oC). Then the measured dielectric properties data was modelled using Debye model in order to relate quantitatively the dielectric properties to microwave heating mechanisms. The analysis carried out gives a clear picture of interaction of ε-cap with microwave energy and its heating mechanism in microwave assisted polymerisation process. This study concluded that microwave heating mechanism of the ε-cap in the measured range may be dominated by the dipole reorientation.

Catechin that is known for its antioxidant, antihypertension and anticancer properties can be obtained from Areca catechu. In this study, accelerated water extraction (AWE) method was used to extract catechin from A. catechu seeds. The extraction parameters tested were temperature (120, 140 and 160 °C), static time (5, 10 and 15 min) and static cycle (1, 2 and 3 cycles). A. catechu extracts were analysed using liquid chromatography time-of-flight mass spectrometry to quantify the amount of catechin. Highest oil yield of 390.00-mg oil/g sample was obtained at temperature of 140 °C, 15 min of extraction time and 3 cycles. On the other hand, the highest catechin amount of 0.0716-mg catechin/g sample was obtained at 140 °C, 10 min and 2 cycles. The effect of extraction temperature was studied using the second-order kinetic model, and it showed good regression coefficient of more than 0.99. It suggests that the model could be applied to describe the extraction of catechin from A. catechu seeds. Based on the model, the initial extraction rate, the equilibrium extraction capacity and the extraction rate coefficient were evaluated to explain the AWE process at temperatures ranging from 120 to 160 °C. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.

Supercritical fluid extraction of α-tocopherol and β-carotenoids from crude palm oil offers an excellent method over other existing conventional methods. Supercritical fluid extraction was developed in the early and mid-1980s to reduce the use of harmful organic solvent in the laboratory. The present paper reviews the applications of supercritical fluid extraction technology in extraction of palm oil using CO2and R 134a fluids. Carbon dioxide is non- toxic, having low critical pressure (74 bar) and temperature (32°C) which minimize the thermal degradation of product but it has a limited dissolving power for solutes of high polarity and high molecular weight in the supercritical state and it also requires higher pressure of upto 500 bar and this high pressure operation requires high operation cost and high capital cost. R134a is an alternative low pressure, non-reactive, non-flammable, non-toxic, non-ozone depleting and has comparable solvent properties as that of CO2. R-134a needs only its temperature or pressure to be controlled in order to control the conditions of extraction or product isolation. This allows simple control of the process.

This work was aimed to evaluate the adsorptive nature of palm oil mill effluent sludge ash for methylene blue dye removal in aqueous solution. Two types of palm oil mill effluent sludge collected from different treatment ponds, i.e. anaerobic and biopolishing were burnt to ash, and treated with 5 M HCl. The treated and untreated adsorbents were characterized for surface area and morphology. Methylene blue dye adsorption was carried out in laboratory at room temperature, and the adsorption data were analyzed based on equilibrium isotherm and kinetic models. The surface area of ash-adsorbents was found to increase more than 12 times after HCl treatment. The highest surface area recorded was 218 m2/g. Equilibrium data of ash-adsorbents obeyed Langmuir isotherm to linear approximation suggesting the monolayer uptake of methylene blue dye. The highest maximum uptake of 50.7 mg/g methylene blue dye (50% removal) was demonstrated by HCl-treated biopolishing ash-adsorbent at initial concentration of 200 m...

In this study, supercritical carbon dioxide is chosen for the extraction and purification of omega-3 fatty acids from Hevea brasiliensis (rubber) oil because this method is environmental friendly and the extracted oil has improved nutritional and functional values. In addition, extraction using this method also can prevent organic solvent residual inside the extracted oil. During the extraction using supercritical carbon dioxide, the oil yield is increased with the increase of temperature and pressure. The best operating condition is pressure of 30 MPa, and temperature of 80 C giving 21.4714% oil yield. The analysis of fatty acids composition is using gas-chromatography. The extracted rubber seeds oil is converted to fatty acids methyl esters (FAME) make it more accessible for chromatogram analysis. From the analysis, the omega-3 fatty acids inside rubber seeds oil especially alpha-linolenic acid (ALA) is the highest compare to soybean oil and olive oil. Beside this, rubber seeds oil also contains oleic acid which is omega-9 and linoleic acid is omega-6. This is the reason rubber seeds oil can be regard as oleic-linolenic seed oil. Alpha-linolenic acid is the precursor to convert polyunsaturated fatty acids (PUFAs) to docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Oleic acid (Omega-9) has the potential for heart protection and cancer prevention but still in the state of prove. On the other hands, the linoleic acid, the element of omega-6 has the benefits to treat to treat arthritis and autoimmune disease. Therefore, rubber seeds oil has very high potential to be developed into difference products in difference industries such as pharmaceutical, cosmetics, oleochemical and foods.

The stability of roselle anthocyanins was investigated under three different heat treatments (60, 80 and 98C). The dry red powder from roselle calyces was produced using spray-drying technique using four different encapsulating agents, i.e., maltodextrin, gum arabic, a combination of maltodextrin and gum arabic, and soluble starch. The four types of matrices increased the half-life of the pigments during heat treatment, especially at 98C (P < 0.05), compared with the roselle extract as the control. Heat treatment results showed that the combination of maltodextrin and gum arabic had the lowest degradation kinetic rates at 60 and 80C. Arrhenius parameters' results further confirmed that the degradation of anthocyanins was strongly dependent on the operating temperatures during heat treatment. In this study, all encapsulating agents, except the soluble starch, largely elongated the half-life of roselle anthocyanins compared with the nonencapsulated anthocyanins. A spectrum of natural, red-hue primer colorants is derived from roselle plant extracts, which is substantially free of alkaloids, enzymes, aroma or solvent residuals, and is microencapsulated to ensure good stability and shelf life. This study measured the thermal stability and suitability of the microencapsulated natural colorants. The colorants are for functional use in the food, pharmaceuticals, cosmetics and other industries.

This study aims to evaluate the adsorptive properties of oil palm empty fruit bunch for the removal of cationic pollutants in water. The untreated and hydrochloric acid-treated empty fruit bunches were characterized based on pH of adsorbent, specific surface area and surface functional groups. The adsorbents were then used to challenge varying concentrations of methylene blue dye and copper (II) in aqueous solution. Results show that the specific surface area of empty fruit bunch decreased upon the treatment with hydrochloric acid. The untreated adsorbent displays a higher equilibrium removal of the target pollutants due to its higher specific surface area of 28.4 m2/g. The maximum removal were recorded as 0.103 and 0.075 mmol/g for methylene blue and copper (II), respectively. Oil palm empty fruit bunch is a promising candidate for the removal of cationic pollutants in aqueous solution.

This study was aimed to evaluate the dielectric properties of the reactants mixture at varying temperatures and concentrations for microwave-assisted adsorbent preparation, and to study the adsorptive characteristics of the resultant adsorbents. Palm kernel shell (PKS) was used as the precursor while potassium hydroxide (KOH) was employed as the activator. Different concentrations of KOH solution and ratios of KOH:PKS of 0:1, 0.5:1, 1:1, and 2:1 were prepared, and the measurement of the dielectric properties was performed using open-ended coaxial probe method. Results indicate that the relative dielectric constant, εr' is inversely proportional to the frequency, f. The trends of relaxation time, τ and penetration depth, DP with respect to the frequency and temperature were also reported. Adsorbent prepared using a higher ratio of KOH shows a greater removal of methylene blue. Dielectric properties are imperative especially for selecting suitable operating conditions and in designing the applicator for effective preparation of adsorbent.

Soxhlet extraction which is also known as solvent extraction refers to the preferential dissolution of oil by contacting oilseeds with a liquid solvent. This is the most efficient method to recover oil from oilseeds, thus solvent extraction using hexane has been commercialized as a standard practice in today’s industry. In this study, soxhlet extraction had been used to extract the rubber seed oil which contains high percentage of alpha-linolenic acid. In addition, the different solvents will be used for the extraction of rubber seed oil such as petroleum ether, n-hexane, ethanol and water to study the best solvent to extract the rubber seed oil so the maximum oil yield can be obtained. On the other hands, the natural resource, rubber belongs to the family of Euphorbiaceae, the genus is Hevea while the species of rubber is brasiliensis. Rubber (Hevea brasiliensis) seeds are abundant and wasted because they had not been used in any industry or applications in daily life. The oil of rubber seeds had been found that contained a significant percentage of long chain polyunsaturated fatty acids especially alpha-linolenic acid (ALA). Alpha-linolenic acid is one of the important elements of omega-3 fatty acids which play important roles in human metabolism, not only playing structural roles in phospholipid bilayers but also acting as precursors to bioactive molecules. Moreover, rubber seed oil also contains a high percentage of oleic acid and linoleic acid, these all are valuable compounds. Thus, rubber seed oil can be regarded as a plant derived oleic-linolenic acid. Rubber seeds can be considered as good sources for human food, animal feed and biofuel with its high content of fat, protein, amino acids and fatty acids. Therefore, it is important to study the method of extraction to extract the valuable components from rubber seeds, purify the extracted seed oil, so that the rubber seeds oil can be utilized into difference industries pharmaceutical, food, oleochemical and cosmetics.

Waste carbon powder from pyrolysis of discarded tyre was converted into activated carbon for decolourization of metylene blue (MB). The precursor was activated using ZnCl2 (ZC), recycled ZnCl2 solution from the earlier activation (RC), and irradiated water (MC). Activated carbons were characterized according to surface area and morphology. The values of surface area were recorded as 288, 104 and 113 m2/g for ZC, RC and MC, respectively. The decolourization of MB was observed to have the following order: ZC>MC>RC. The maximum adsorption capacity of MB by ZC was found to be 154 mg/g. Adsorption data for all activated carbons studied obeyed Redlich-Peterson isotherm for which the process could be described as mixed features of Langmuir and Freundlich models. The kinetics data were well-fitted to pseudo-second-order model, suggesting the chemisorption process.