Structural and thermal behavior of lignin-based formaldehyde-free phenolic resin

Phenolic resin has been widely used in various field applications and is a crucial resin in daily life. However, the raw materials used for producing phenolic resin are quite costly and harmful to the consumer. Therefore, the production of bio-based phenolic resins has attracted considerable scientific and industrial interest. The utilization of bio-based substituents for phenol and formaldehyde as phenolic resin raw materials is described in this paper. The structural properties of the prepared bio-based phenolic resin are established by FTIR and NMR, and the thermal stability is determined by DSC and TGA. The presence of the methylene bridge functional group at around 1460 cm1 confirms the formation of phenolic resins. The resins have a decomposition temperature of about 300 °C and exhibit good thermal stability. This confirmed structure and thermally stable resins could be used to substitute the current commercialized phenolic resins

Pembangunan e-modul pembelajaran enjin diesel untuk kursus teknologi automotif

"Penyelidikan ini adalah untuk membangunkan satu reka bentuk e-modul pembelajaran pelajar kursus Teknologi Automotif di kolej vokasional. Tujuan penyelidikan ini adalah bagi mengenalpasti kesesuaian elemen yang digunakan dalam modul dan reka letak papan cerita yang dibangunkan. Penggunaan e-modul dalam modul vokasional ini dapat memudahkan pemahaman pelajar dan cemerlang di dalam pentaksiran kompetensi. Modul menggunakan Model ADDIE sebagai model dan prinsip pembangunan bahan multimedia serta prinsip hueristik kebolehgunaan bagi pembangunan modul interaktif ini. Proses pembangunan modul menggunakan perisian CourseLab, Audacity, Freemake Video Converter, GIMP yang merupakan antara perisian percuma dan perisian sumber terbuka. Hasil pembangunan modul diuji sebanyak dua kali ke atas seramai 30 orang pelajar Kursus Teknologi Automotif yang terlibat di dalam penyelidikan ini dan 7 orang pensyarah dari kolej vokasional dipilih sebagai responden kajian. Soal selidik digunakan sebagai instrumen oleh pengkaji dalam kajian ini. Set soal selidik ini terdiri dari tiga set iaitu untuk kesesuaian elemen modul, kesesuaian papan cerita dan pembangunan e-modul pembelajaran. Soalan-soalan yang dikemukakan pada ketiga-tiga set akan dijawab berdasarkan skala likert. Maklumat dan data yang diperoleh akan dianalisis dengan menggunakan Statistical Packages for Social Sciences (SPSS). Kesimpulan daripada data dan maklumat yang diperolehi menunjukkan satu e-modul pembelajaran dapat dibangunkan dengan mempunyai aspek rekabentuk (skor min = 4.74), aspek persembahan (skor min = 4.67) dan aspek mesra pengguna (skor min = 4.69) yang dapat menarik minat belajar berdasarkan pada purata keseluruhan skor min.

Structural and thermal analysis of bio-based polybenzoxazine derived from liquefied empty fruit bunch (EFB) via solventless method

A bio-based polybenzoxazine demonstrating excellent thermal properties was synthesized using phenolic and its derivatives derived from liquefaction of empty fruit bunch (EFB) fibres to fulfill green chemistry principles. The liquefied EFB was reacted with furfurylamine and paraformaldehyde through a Mannich condensation reaction. For comparison purposes, a guaiacol polybenzoxazine was synthesized using guaiacol as a phenolic component reacted with similar amine and aldehyde. Both types of polybenzoxazine synthesized from liquefied EFB and guaiacol were named L-fa and G-fa, respectively. The structural analysis was performed using Fourier-Transform Infrared (FTIR) and proton Nuclear Magnetic Resonance (1H NMR). It was observed that the synthesis of benzoxazine groups for both types of polybenzoxazine was successful with the formation of the oxazine ring. Thermal stability showed that liquefied EFB polybenzoxazine (L-fa) has higher thermal stability above 360 °C compared to guaiacol-polybenzoxazine (G-fa), which is higher is 280 °C due to the complex structure of the lignin derivative in the liquefied EFB. For polymerization behavior, L-fa exhibit two exothermic peaks compared to three peaks on G-fa, indicating that L-fa is more reactive due to additional polymerizable sites present in L-fa. This work widens the synthesis route for the preparation of bio-based benzoxazine derived from oil palm waste which will perpetuate outstanding evolution towards the sustainable development of the bio-based polymeric industry

Photocatalytic degradation of triclocarban in artificial bathroom greywater by modified tio₂ nanotubes coated with zeolite (TNTs/ZEO)

Xenobiotic organic compounds (XOCs) originated from anti-microbial personal care products (PPCPs) including triclocarban (TCC) are emerging contaminants can cause hazardous effect on water environment. The study aims to measure the degradation of the XOCs which is TCC to promote water quality protection measures. Hence, objective of this research is to study the photocatalytic degradation of TCC in greywater. Photocatalytic degradation was enhanced by modification of photocatalyst which is TiO₂ nanotubes with the coating of zeolite (TNTs/Zeo). TNTs/Zeo catalyst were formed by application of electrochemical anodization (ECA) for TiO₂ nanotubes formation and electrophoresis deposition (EPD) in coating zeolite. The characteristics of catalyst were verified using FESEM/EDS, and XRD. In order to control the presence of TCC, the optimization of photocatalytic degradation of TCC was designed via factorize central composite design (FCCD) design matrix of RSM by depending on pH value (3 - 10), TNTs/Zeo catalyst loading size (0.5 cm² - 1.0 cm²) and irradiation time (10 - 60 minutes) as variables. The photocatalytic degradation experiments have been conducted under natural sunlight radiation. The overall finding has directed to the pH value 11, TNTs/Zeo catalyst loading 0.75 cm², and irradiation time 50 minutes were the optimum conditions of photocatalytic degradation on TCC that has provided the maximum efficiency of photocatalytic degradation up to 81.2 % removal of TCC concentration. Based on kinetic study by following Langmuir-Hinshelwood (L-H) model and pseudo first order, the significant constant rate obtained at pH 11 which was 0.048 ppm/min, 0.75 cm² of TNTs/Zeo catalyst loading size achieved 0.047 ppm/min and 5 ppm of TCC initial concentration reached 0.037 ppm/min. Furthermore, there eleven intermediate products were detected after the whole process of photocatalysis. In addition, the photocatalytic degradation rate of TCC from first and fifth cycles were 94.2 % and 77.4 % where it still can be considered as significant TCC degradation rate

Photodegradation of basic red 51 in hair dye greywater by zinc oxide nanoparticles using central composite design

The current work aimed to optimize the photocatalysis of Basic Red (BR51) in hair dye greywater (HDG) using zinc oxide nanoparticles (ZnO NPs) by response surface methodology (RSM). The independent factors included ZnO NPs dose (10–200 mg), pH (3–9) and BR51 (1–10 ppm). The photocatalysis efficiency of the ZnO NPs was determined based on the decolorization of BR51 and chemical oxygen demand (COD) reduction. The photocatalysis mechanism was investigated based on the ZnO NPs analyses by field emission scanning electron microscopy/energy dispersive X-ray analysis (FESEM/EDX), Fourier transform infrared (FTIR) spectroscopy, Thermogravimetric analysis and differential scanning calorimetry (TGA/ DSC), atomic force microscope (AFM), and Raman spectroscopy. The optimal operating factors for the photocatalysis of BR51 were recorded at 131.56 mg of ZnO NPs, pH 3, and 7.47 ppm of BR51, where 72.18 vs. 70.93% of BR51 removal and 82.71 vs. 83.56% of COD removal were the observed and predicted results recorded with an R2 coefficient of 0.92. The independent variables exhibited a significant (p < 0.05) interaction with 95% of confidence level. FESEM and AFM analysis showed that the grain sizes of ZnO NPs were uniform before photodegradation but aggregated afterwards. FTIR analysis revealed the main functional groups of ZnO NPs that contributed to the removal process were –C–O, =C–H, C=C, –C–O–C, and OH. TGA revealed a mass loss and exothermic reaction due to desorption of the chemisorbed water. Raman spectroscopy indicated the crystal structure of ZnO for ZnO NPs (before) and the decrease in the crystalline quality for ZnO NPs (after). These findings indicated that ZnO NPs have a high potential for the photocatalysis of BR51 in HDG

Three-dimensional flow of nanofluid over a non-linearly Permeable shrinking sheet

The nanofluid flow past a permeable non-linear shrinked surface for three-dimensional case is considered in this paper. The governing equations are first modelled, and the similarity transformation technique is conducted with the aim to obtain a set of nonlinear ordinary differential equations systems from the nonlinear partial differential equations form. The solutions are attained numerically by solving the obtained similarity equations and then solved by the shooting approach. The physical explanation on the impact of the governing parameters is presented through tables and graphs. The influences of the governing parameters on the local Reynolds number in x and y direction, local Nusselt number along with the velocity profiles have been discussed. Additionally, this present problem also discovered the existence of dual solutions. The obtained result has been compared with previous open literature results and it is revealed to be in good agreement

Effect of Rice Husk Ash (RHA) as a Pozzolan on the Strength Improvement of Cement Stabilized Peat

Cement is one of the most effective conventional methods for peat soil stabilization. However, this method is not environmentally friendly because the use of too much cement causes much carbon dioxide to be produced for cement production. Rice husk ash (RHA) is applied as substitution for Ordinary Portland Cement (OPC) in this study. RHA is waste generated from agricultural activities formed from the rice husk combustion process and will help mitigate pollution and disposal problems by recycling this waste in peat soil stabilization. Therefore, the study aims to investigate the basic characteristics of Pontian peatlands and assess the strengths of peat soils by using RHA. Laboratory tests including moisture content, organic content, fibre content, liquid limit, particle size analysis, unconfined compressive strength (UCS) and the Scanning Electron Microscope (SEM) together with Energy Dispersive X-Ray (EDX) analysis were experimented to investigate properties base of peatlands located at Pontian with the proportion of mixing ratio of RHA between 5% to 20%. Based on UCS test, at RHA 5% replacement mixture with cement shows the higher soil strength compared to other RHA replacement mixture with cement with the strength of 185 kN/m2, 233 kN/m2, and 278 kN/m2 for 7, 14 and 28 days of curing periods, respectively. The research found that RHA can promote peat stabilization, particularly in samples with a 95% cement ratio and 5% RHA that can be a countermeasure for environmental issues such as pollution and energy us

Effect of catalysts on the yield and properties of lignin form microwavedassisted acetosolve extraction of oil palm empty fruit bunch fibres.

cetosolv is an enhancement organosolv technique utilising acetic acid as solvent and produces high purity of lignin. However, the limitation of this technique in the conventional heating method is the high energy consumption during a long reaction time. Therefore, the employment of microwave is used to overcome this limitation with the expectation of a lower power consumption and short reaction time. In this study, three types of catalysts, sulphuric acid (H2SO4), aluminium choride (AlCl3), and chromium nitrate [Cr(NO3)3] were used to investigate the lignin extraction performance and its properties from microwave-assisted acetosolv (MWA) treatment of oil palm empty fruit bunches (EFB). The highest yields of lignin (76.98%) were obtained using an aqueous solution of acetic acid combined with 3.0% of H2SO4 under 110°C for 30 min. Meanwhile, AlCl3 performed almost similar to H2SO4, providing lignin yield of 71.57% at the highest temperature of 110°C. The usage of microwave-assisted technique also produces a high yield and high purity of lignin. It is also proven that AlCl3 can be a substitute to Bronsted acid for lignin extraction. However, Cr(NO3)3 was found not suitable for the lignin’s extraction despite having a high potential for cellulose extraction

Effect of temperature on the yield of lignin extracted using microwave-sssisted acetosolv from empty fruit bunch fibers

Acetosolv technique is considered as one of the best alternative ways to extract technical lignin from biomass as it has high efficiency and environmentally friendly. In this study, microwave assisted acetosolv technique was used to extract lignin from oil palm empty fruit bunch (OPEFB) in the presence of 3% sulfuric acid catalyst reacted at various temperature. The yield of the extracted acetosolv lignin was calculated using the modified Technical Association of the Pulp and Paper Industry biomass composition analysis (TAPPI) method. The result showed that, as the temperature increased from 90 to 110 °C, the yield of lignin extracted also increase from 43.07 to 76.98%. The presence of guaiacyl and p-coumarate indicates the presence of active sites at C-3 and C-5 of the aromatic ring for polymerization reactions. Scanning Electron Microscopy images showed that removal of lignin is intensified as the microwave-assisted acetosolv temperature increased

Chlorella vulgaris broth harvesting via standalone forward osmosis using seawater draw solution

Microalgae biomass gains interests for its promising sustainability as feed-stock in biofuels production. However, high-energy cost for biomass cultivation and harvesting must substantially be reduced to enhance its viability. This study evaluates the application of standalone forward osmosis (FO) and aeration as fouling control for Chlorella vulgaris dewatering using seawater as draw solution (DS). Overall results reveal the feasibility of using seawater as DS and aeration for membrane fouling control. Application of seawater as the DS offers desirable performance as it produces high water fluxes (>6 L/m2 h) at volumetric concentration factors of up to 6×. The air bubbling significantly increases the flux even at low rates by up to 67%. The proposed system is suitable for handling freshwater microalgae, especially when farmed near the seashore. Technoeconomic analyses and implementation optimization of proposed study are important to gauge its true potential and feasibility, thus will be subjected to future study