Production of synthetic vanillin from coconut husk lignin via alkaline nitrobenzene oxidation

Vanillin is one of the essential constituents that provide the flavor and aroma characteristics to the vanilla extract. Due to the increasing market demands, the production of synthetic vanillin has gradually developed as an alternative to the complex production of natural vanillin from vanilla orchid beans. Recently, the chemical production of synthetic vanillin from biomass lignin has gained significant attention as the more environmental friendly alternative for vanillin production. Accordingly, lignin isolated from three sources of lignocellulosic biomass which are oil palm empty fruit bunch (OPEFB) fiber, coconut husk and kenaf fiber were studied and compared prior to be used in the vanillin derivation process. Among the biomass studied, the highest lignin fractions were recovered from the coconut husk which exhibits the best characteristics of lignin in term of structure, purity and thermal behavior. Therefore, only the coconut husk lignin was used for further study. Coconut husk lignin was subjected to an alkaline oxidation at 160 ºC for 2.5 hours, using 0.40 mL nitrobenzene as the oxidant. Approximately 2.83 % of vanillin was successfully produced and its presence in the oxidized mixture was identified by using the high performance liquid chromatography (HPLC) and gas chromatography (GC) method. Meanwhile, the crystalline structure of purified vanillin was verified using the Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (H1NMR) method. In order to maximize the production yield of vanillin, several variables were considered for optimization using the response surface methodology (RSM) which includes oxidation temperature, oxidation time and volume of nitrobenzene. A maximum yield of 4.01 % vanillin was obtained from coconut husk lignin at 140 ºC for 2.8 hours using 0.44 mL nitrobenzene. The production yield of vanillin at these optimum conditions was compared with the oxidation of OPEFB and kenaf fibers lignin. The comparison shows the highest yield was obtained for the coconut husk lignin oxidation. As a conclusion, the yield of vanillin was improved at low oxidation temperature

Synthesis of Biodiesel from Used Frying Oil Using Modified Banana Peel Waste as A Heterogeneous Catalyst

In this study, biodiesel was synthesised from a transesterification reaction of used frying oil (UFO) catalysed by modified banana peel waste (Modified-BPW). The catalyst properties were characterised using Fourier Transform Infrared Spectrometer (FTIR) and Scanning Electron Microscopy (SEM) analyses. The reaction parameters were varied to evaluate the optimal reaction parameters that could influence the biodiesel yield, such as methanol to oil molar ratio, catalyst loading amount and water content presence in the UFO at a fixed reaction time of 2 hours and a reaction temperature of 65°C. The catalytic activity resulted in the reaction condition of 12:1 of methanol to oil molar ratio, 1 wt.% of catalyst dosage and 0.5 wt.% water content in UFO, obtaining the highest biodiesel yield of 88.7%. The results indicated that the Modified-BPW could be a promising catalyst for biodiesel synthesis from UFO

Synergistic effect of probe sonication and ionic liquid for extraction of phenolic acids from oak galls

Phenolic acids of oak gall were extracted using ultrasonic-probe assisted extraction (UPAE) method in the presence of ionic liquid. It was compared with classical ultrasonic-bath assisted extraction (CUBAE) and conventional aqueous extraction (CAE) method, with and without the presence of ionic liquid. Remarkably, the UPAE method yielded two-fold higher extraction yield with the presence of ionic liquid, resulting 481.04 mg/g for gallic acids (GA) and 2287.90 mg/g for tannic acids (TA), while a decreased value of 130.36 mg/g for GA and 1556.26 mg/g for TA were resulted with the absence of ionic liquid. Intensification process resulted the highest yield of 497.34 mg/g and 2430.48 mg/g for GA and TA, respectively, extracted at temperature 50 °C with sonication intensity of 8.66 W/cm2 and 10% duty cycle, diluted in ionic liquid, 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [Bmim][Tf2N] at concentration of 0.10 M with sample-to-solvent ratio 1:10 for 8 h. Peleg’s model successfully predicted the UPAE process confirming that extraction capacity is the controlling factor in extracting phenolic acids. Hence, it can be concluded that UPAE method and ionic liquid have synergistic effect as it effectively enhanced the extraction efficiency to increase the bioactive constituents yield

Tissue paper from banana peels: a preliminary study

Banana was originally from Malaysia and it is a herbaceous plant of the genus of Musa and family of Musaceae. Banana is contributing 16% of the world’s total fruit productions [1]. The cultivation of the banana plant is mainly for its fruits. In some countries, banana fruit and its peel are considered to be the golden fruit of nature because they are providing healthy digestion and promote natural beauty to the body with essential nutrients. Moreover, banana fruit help in preventing anemia, stress, ulcers, and other minor illness. Banana is also considered to be a functional food source against cancer and heart disease and a good source of natural antioxidants for foods [2]. A large quantity of bananas is produced annually and its peel, which accounts for about 35% of the whole fruit weight, is mostly discarded as waste. Approximately 36 million tonnes of banana peel is generated every year and this is a potential material for further utilisation [3]

The level of knowledge and attitude related to HIV/AIDS among health science students

HIV/AIDS is a worrying health issues among Malaysian young adult. This is probably due to the level of knowledge and attitude related to the disease. This cross-sectional study was conducted to determine the level of knowledge and attitude related to HIV/AIDS among health science students in a Malaysian public university. A total of 216 students were involved in this research (male and female). Respondents were recruited using stratified random sampling. Both level of knowledge and attitude related to HIV/AIDS was assessed by using HIV Knowledge Questionnaires (HIV-KQ). The questionnaires consisted of three parts. The first part was about sociodemographic, second part knowledge related to HIV/AIDS and the last part was about the attitude related to HIV/ AIDS. Most of the respondents were Malays (67%), followed by Chinese (26%), Indians (5%) and others (2%). The results found that the level of knowledge about HIV/AIDS among 1st year and 2nd year health science students were low. The average of HIV/AIDS knowledge scores of all respondents were 9.41±2.876. Their main source of information for HIV/AIDS came from internet, newspaper and television. Majority of the respondents showed more openness and positive attitudes towards HIV/AIDS. In conclusion, although the level of knowledge about HIV/AIDS among health science students in a malaysian public university is low, they showed positive attitudes towards HIV/AIDS. Thus more internet based and youth-friendly education program are required

The physical properties of submicron and nano-grained La0.7Sr0.3MnO3 and Nd0.7Sr0.3MnO3 synthesised by sol–gel and solid-state reaction methods

La0.7Sr0.3MnO3 (LSMO) and Nd0.7Sr0.3MnO3 (NSMO) possess excellent colossal magnetoresistance (CMR). However, research work on the neodymium-based system is limited to date. A comparative study between LSMO and NSMO prepared by sol–gel and solid-state reaction methods was undertaken to assess their structural, microstructural, magnetic, electrical, and magneto-transport properties. X-ray diffraction and structure refinement showed the formation of a single-phase composition. Sol–gel-synthesised NSMO was revealed to be a sample with single crystallite grains and exhibited intriguing magnetic and electrical transport behaviours. Magnetic characterisation highlighted that Curie temperature (TC) decreases with the grain size. Strong suppression of the metal–insulator transition temperature (TMI) was observed and attributed to the magnetically disordered grain surface and distortion of the MnO6 octahedra. The electrical resistivity in the metallic region was fitted with theoretical models, and the conduction mechanism could be explained by the grain/domain boundary, electron–electron, and electron–magnon scattering process. The increase in the scattering process was ascribed to the morphology changes. Enhancement of low-field magnetoresistance (LFMR) was observed in nano-grained samples. The obtained results show that the grain size and its distribution, as well as the crystallite formation, strongly affect the physical properties of hole-doped manganites

Effect of NiO nanoparticle addition on the structural, microstructural, magnetic, electrical, and magneto-transport properties of La0.67Ca0.33MnO3 nanocomposites

Incorporation of the secondary oxide phase into the manganite composite capable of enhancing low-field magnetoresistance (LFMR) for viability in high-performance spintronic applications. Polycrystalline La0.67Ca0.33MnO3 (LCMO) was prepared via the sol–gel route in this study. The structural, microstructural, magnetic, electrical, and magneto-transport properties of (1−x) LCMO: x NiO, x = 0.00, 0.05, 0.10, 0.15 and 0.20 were investigated in detail. The X-ray diffraction (XRD) patterns showed the coexistence of LCMO and NiO in the composites. The microstructural analysis indicated the amount of NiO nanoparticles segregated at the grain boundaries or on the surface of LCMO grains increased with the increasing secondary phase content. LCMO and NiO still retained their individual magnetic phase as observed from AC susceptibility (ACS) measurement. This further confirmed that there is no interfacial diffusion reaction between these two compounds. The NiO nanoparticle acted as a barrier to charge transport and caused an increase in resistivity for composite samples. The residual resistivity due to the grain/domain boundary is responsible for the scattering mechanism in the metallic region as suggested by the theoretical model fitting, ρ(T)=ρ0+ρ2T2+ρ4.5T4.5. The magnetoresistance values of LCMO and its composites were found to increase monotonically with the decrease in temperature. Hence, the LFMR was observed. Nonetheless, the slight reduction of LFMR in composites was attributed to the thick boundary layer created by NiO and impaired the spin polarised tunnelling process

Optimization and mathematical modeling of green solvent-mediated extraction of essential oil from Citrus hystrix DC. leaves

Citrus hystrix DC. leaves or Kaffir lime leaves is known for its prominent organoleptic properties and therapeutical functionalities but are still underutilized as a source for the high-demand citrus-based essential oil (EO), due to the limitation of conventional hydrodistillation (HD) method that results in low yield. Green solvents such as natural deep eutectic mixture and subcritical-phase water described in previous studies not only improved the bioproduct extraction but also friendlier to the environment. However, the use of a natural deep eutectic solvent (NADES) requires correct formulation to be effective, while adopting water at subcritical conditions can affect the quality of EO. Hence, in this work, the application and the effectiveness of natural deep eutectic solventassisted hydrodistillation (NADES-HD) and subcritical water extraction (SWE) methods were comparatively studied. Based on screening and optimization studies, NADES-HD and SWE techniques successfully improved the EO yield by twice (1.32% w/w), and almost fourfold (2.14% w/w) respectively, in comparison to conventional HD (0.57% w/w) at their corresponding optimum extraction conditions. Both methods were well-fitted to the onesite kinetic desorption model at an extraction rate (k) of 0.0107 to 0.0136 min-1 and 0.0224 to 0.0463 min-1 for NADES-HD and SWE, respectively. Assessment of the mass transfer behavior estimates that the effective diffusivity, (D) values for NADES-HD and SWE corresponded to 3.68 x 10-6 to 5.59 x 10-6 cm2/s and 8.91 x 10-8 to 1.47 x 10-7 cm2/s, respectively, and obeys the Fick’s second law of diffusion. Meanwhile, for thermodynamics behavior, both methods were identified as exergonic and spontaneous processes with the free Gibbs energy (ΔG) values ranging from 6.83 to 8.73 kJ/mol for NADES-HD and 2.23 to 4.74 kJ/mol for SWE. The chemical profile analysis revealed that the SWE produced more EO compounds, where isopulegol (52.21%) was the predominant constituent, meanwhile NADES-HD has yielded EO that is rich in citronellal (75.99%), similar to conventional HD (75.04%). Besides, SWE-extracted EO exhibited a superior antioxidant activity while the EO extracted by NADES-HD demonstrated a better antimicrobial activity. The physical characterization of the post-extraction leaves samples indicated that the lignocellulosic structures of SWE-extracted leaves were severely disrupted compared to the damages observed on NADES-HD and conventional HD samples, hence implying the reason for the higher EO yield obtained by the SWE process. In brief, NADES-HD and SWE are the potential alternatives to conventional HD, where the quantity and quality of EO could be enhanced within a shorter extraction time and at the same time could minimize the energy requirement

Isolation and characterization of vanillin from coconut husk lignin via alkaline nitrobenzene oxidation

Isolation of vanillin from lignin extracted from coconut husk is presented in this study. Phosphoric acid (20%) is employed to precipitate the lignin from the black liquor produced by cooking the mixture of coconut husk and 1M NaOH in steam autoclave at 121°C for one hour. Separation of vanillin from lignin was carried out via oxidation by adding 0.1 g of coconut husk lignin into a mixture of 2M NaOH (10 ml) and nitrobenzene (0.4 ml) in steel capillary bomb heated at 160°C for 2.5 hours. Detection and quantification of vanillin presents in the lignin oxidized mixture was performed by liquid and gas chromatography. The recovery of vanillin from the mixture was done via crystallization process by dissolving the mixture in acetone and heats up to 60°C with periodic stirring. Vanillin crystal appeared by rapidly cooled the heated mixture in the ice bath. The vanillin obtained was characterized by Infrared Spectroscopy (FTIR) for component verification. Component isolation by HPLC and GC-FID denoted the retention time of vanillin appeared around 18.852 minutes and 16.913 minutes respectively. A yield of 2.83% vanillin was isolated from 0.1 g lignin sample and the result of FTIR characterization has suggested that the isolated compound is vanilli

Screening of factors influencing the yield of Citrus hystrix leaves essential oil extracted via pressurized hot water extraction based on resolution V fractional factorial design

Pressurized hot water extraction (PHWE) could be a better alternative in enhancing the yield of valuable Citrus hystrix leaves essential oil. Thus, the fractional factorial design based on resolution V was used to assess the crucial factors that affect the essential oil yield (%Y) extracted from Citrus hystrix leaves through a PHWE. A maximum Y% of 1.63% was successfully isolated at conditions involving 0.08% moisture content, 1 mm particle size, 1:0.2 ml/g solvent-to-sample ratio, 30 min extraction time, and 120°C extraction temperature. Moisture content and particle size were the main effects that significantly affect the %Y, while the extraction time and solvent-to-sample ratio exhibited a moderate effect on %Y, followed by extraction temperature that showed the least effect on %Y. A developed regression model has shown good correlation and adequacy on %Y. Based on the compositional analysis, neoisopulegol hydrate appears to be the main constituents of the oil obtained