Fabrication of Transparent Composites from Pinaceae Wood Packaging Residues

In the 21st century, mankind has witnessed the rapidly development of all industries with a lot of new products in a variety of types and designs. However, this development has been also causing many problems with the society and the ecological environment such as a wasteful excess of products, exhaustive exploitation of natural resources, indiscriminate deforestation, and waste pollution affecting the living environment, ecosystem, and human health. Many organizations and governments are calling for environmental protection, limit waste emissions, and find good solutions to use the recycled materials as raw materials in production plants. This study would like to provide a solution which not only utilizes waste packaging Pinaceae wood for recycling as raw material but also supplies to the market with a green product responding to the durability requirements in fact. Pinaceae wood packaging residues were chemically processed through two stages. The amount of lignin extract from Pinaceae was determined by the method of Tappi 222 om-02 which was significantly influenced by the extraction parameters such as temperature, time and concentration of the treatment solution. Morphological modification of wood materials was analyzed by SEM micrographs. In particular, the mechanical properties of the Epoxy/TPW2 composite green material have been significantly improved with increasing up to 206–540 % compared to the original Pinaceae wood. The optical properties of the wood have completely changed from opaque pine wood with the optical transmittance of 8 % into transparent composite material with the optical transmittance up to 85 % using UV-vis spectroscopy analysis

Influence of Curing Regimes on Engineering and Microstructural Properties of Geopolymer-Based Materials from Water Treatment Residue and Fly Ash

Geopolymerization is a new method for treating water treatment residue (WTR) from water purification plants to reduce the amount of stored land in urban areas. Polymeric bond formation depends on the curing conditions. In this study, the curing conditions suitable for subsequent treatment to save energy consumption and production costs in the future application were investigated. The WTR had a high aluminosilicate content with low alkaline activity, so fly ash (FA) was added to FA and WTR mixtures in the ratio of 40 and 60 weight percent (% in wt.), respectively. The moisture content of the mixtures ranged in 12–15%, suitable for semi-dry pressing to form pellets. After this formation, the geopolymer samples were cured under different conditions (room temperature, microwave oven, in dryer at 110°C, and in autoclave with hydrothermal condition). The experimental results showed that the hydrothermal samples had better properties, such as pH<9, high stability of mechanical strength over 3.5 MPa, and soft coefficient over 0.75. The microstructural properties were investigated using modern analytical tools, such as XRD, SEM, FTIR, and NMR, to detect the chemical functional groups of the aluminosilicate networks in the geopolymer matrix and the close relationship among the properties and its microstructure

Evaluation of the engineering and physicochemical properties of a novel geopolymer binder from red mud, rice husk ash, and diatomaceous earth using sodium silicate solution as alkaline activator

Geopolymers, also known as alkali-activated pozzolan cements, have been recently gaining attention as an alternative binder for concrete because of its potential to lower the environmental impact of construction, to utilize waste as raw materials of alumino-silicates, and to enhance the material performance. In this study, engineering properties of sodium silicate activated geopolymer-based material produced from the ternary blend of red mud (RM) waste, rice husk ash (RHA) and diatomaceous earth (DE) which was optimized with statistical design of experiment and multi-response surface method. Using the augmented simplex lattice mixture design, ten mix proportions of RM, RHA, and DE were prepared and mixed with 15%, 20%, 25%, and 30% (by weight of the solid) water glass solution (WGS) to produce the specimens. After 28 days of curing at room temperature, these specimens were tested for compressive strength (MPa), volumetric weight (kg/m3), thermal conductivity (W/m.K), water absorption (kg/m3), and thermal stability including the mass loss (%), volumetric shrinkage (%) and change in compressive strength (%) when subjected to an elevated temperature of 10000C. By using the desirability function approach on multiple responses, the optimum ternary blend was found in ranges of 14.47-17.07 % RM, 63.43-67.19% RHA, 17.23-21.66% DE mixed with 20-25% WGS to obtain the desirable engineering properties of sodium-silicate activated geopolymer-based material. The predicted engineering properties are in the range of 12-15 MPa for compressive strength, 1297-1307 kg/m3 for volumetric weight, 55-63% for heat resistance in terms of strength gain, 7-8% for volumetric shrinkage, 7.6-8.3% for mass loss, 190-206 kg/m3 for water absorption, and 0.29-0.32 W/m.K for thermal conductivity, respectively. Confirmatory experiments were also carried out an optimal mix (OM) formulation of 15% RM, 65% RHA and 20% DE with WGS concentration in the range of 10 to 30%. Confirmatory runs were also done and the experimental values were found to be in g The study also proposed the reaction mechanism for the formation of the amorphous alumino-silicate geopolymeric networks in the sodium silicate activated geopolymer from the ternary blend of RM, RHA, and DE based on the results provided by SEM-EDS, XRD, and FTIR. This proposed mechanism showed that the tetra-silicates or acid silicic (Si(OH)4 or H4SiO4) dissolved and reacted with the iron oxide (Fe2O3) in RM and DE to form the oligomer precursor (-Fe3+[SiO4]4--). Aside from the formation of precursor tetra-silicates or acid silicic (Si(OH)4 or H4SiO4) from the dissolution of SiO2 of raw materials (RHA and DE), the precursor (-Fe3+[SiO4]4--) was reacted with others precursors (sialate -O-Si-O-Al-O-, sialate-siloxo -O-Si-O-Al-O-Si-O-, sialate-disiloxo -O-Si-O-Al-O-Si-O-Si-O-, tetra-silicate [SiO4]4-, and tetra-aluminate [Al(-)O4]4-) to form the sodium alumino-silicate iron hydroxide polymeric network. The concentration of sodium silicate solution influenced the geopolymer network structure resulting to either an Al-rich or Si-rich geoplymer. Si-rich geopolymer produced stronger geopolymer binder as shown in the findings of the engineering properties of optimized geopolymer at 25% WGS (OM25) which had ratios of Si/Al and Na/Al at 3.5 and 0.8, respectively. OM25 has the highest compressive strength at 17.04 MPa and the lowest water absorption at 191.20 kg/m3 among the geopolymer specimens. Results from the evaluation of physicochemical properties indicated that sodium silicate activated geopolymer from the ternary blend of red mud, rice husk ash and diatomaceous earth produces a lightweight and heat resistant material. These can be used as thermal insulating material for panel building and refractories with minimal environmental impact. A systematic method of optimizing the engineering properties of the geopolymer was proposed and used for a given application with multiple response surface method. Moreover, the proposed reaction mechanism for the formation of the alumino-silicate geopolymeric networks in the geopolymer products was elucidated based on the scientific evidences with complementary results of XRD, FTIR, SEM-EDS, DTA-TG, and MIP. Future studies will therefore explore its potential used as a binder for concrete, and deeper understand the microstructure in relation to its durability performance

Development of geopolymer-based materials from coal bottom ash and rice husk ash with sodium silicate solutions

The coal bottom ash is a solid waste generated from coal-fired thermal power plants that contains high alumino-silicates resources. Rice husk ash was burned from rice husk which has over 80% silica in its chemical composition. The alumino silicates resources in these materials have high reactivity in various conditions such as that of alkaline reactions and thermal reactions. Therefore, both coal bottom ash (CBA) and rice husk ash (RHA) are promising raw materials for synthesizing alkali activated materials through geopolymerization. This study focuses on utilization of CBA and RHA to produce geopolymer – based materials using sodium silicate solution as an alkali activator. This is one of the potential solutions that would not only manage the coal bottom ash but also an avenue to utilize the waste to produce green materials. The production of geopolymer-based materials results to lower energy consumption, minimal CO2 emissions and lower production cost as it valorizes industrial waste. The CBA and RHA were mixed with sodium silicate solution to obtain the geopolymeric pastes. The pastes were molded in 5-cm cube molds according to ASTM C109/C109 M 99, and then cured at room temperature for 28 days. The 28-day geopolymer specimens were tested for engineering properties such as compressive strength (MPa), volumetric weight (kg/m3), water absorption (kg/m3) and thermal conductivity (W/m.K). Microstructure of the best geopolymer sample was characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM). © Springer Nature Singapore Pte Ltd. 2018

Effects of Hydrothermal Reaction Time on the Structure and Optical Properties of ZnO/Graphene Oxide Nanocomposites

In this research, ZnO/GO nanocomposites were successfully synthesized by a simple hydrothermal method using graphene oxide (GO) and zinc acetate dihydrate (Zn(CH3COO)2.2H2O) as the reactants. The effect of the hydrothermal reaction time on the structure and optical property of the ZnO/GO was systematically investigated. The structure, morphology and chemical composition of the samples were measured by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and Raman and Fourier transform infrared (FTIR) spectroscopy, while the optical properties were measured using photoluminescence spectroscopy. The synthesized products consisted of large quantities of one-dimensional (1D) ZnO nanorods (NRs), which were dispersed uniformly on the GO surface. The XRD and Raman results reveal that the ZnO NRs in the fabricated samples had a hexagonal wurtzite structure with high crystalline quality. The FESEM and TEM images reveal that ZnO NRs with an average diameter in the range of ~85–270 nm and length in the range of ~0.3–6 μm were covered with GO sheets. Additionally, it was found that the crystallographic orientation of ZnO NRs was dependent not only on the hydrothermal reaction time but also on the presence of GO in the nanocomposites. However, the addition of GO did not affect the stoichiometric ratio and the crystal structure of ZnO NRs. The room-temperature PL results indicated that, compared to those of pure ZnO, the luminescence of the GO/ZnO nanocomposites was suppressed and shifted towards a higher wavelength (red shift), which was attributed to the incorporation of ZnO NRs within the GO matrix and the formation of a C-O-Zn chemical bond in the nanocomposites. The hydrothermal technique is considered one of the best routes due to its low cost, high growth rates, low-temperature synthesis, controllable crystallographic orientation, particle size, as well as morphology

Effects of Hydrothermal Reaction Time on the Structure and Optical Properties of ZnO/Graphene Oxide Nanocomposites

In this research, ZnO/GO nanocomposites were successfully synthesized by a simple hydrothermal method using graphene oxide (GO) and zinc acetate dihydrate (Zn(CH3COO)2.2H2O) as the reactants. The effect of the hydrothermal reaction time on the structure and optical property of the ZnO/GO was systematically investigated. The structure, morphology and chemical composition of the samples were measured by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and Raman and Fourier transform infrared (FTIR) spectroscopy, while the optical properties were measured using photoluminescence spectroscopy. The synthesized products consisted of large quantities of one-dimensional (1D) ZnO nanorods (NRs), which were dispersed uniformly on the GO surface. The XRD and Raman results reveal that the ZnO NRs in the fabricated samples had a hexagonal wurtzite structure with high crystalline quality. The FESEM and TEM images reveal that ZnO NRs with an average diameter in the range of ~85–270 nm and length in the range of ~0.3–6 μm were covered with GO sheets. Additionally, it was found that the crystallographic orientation of ZnO NRs was dependent not only on the hydrothermal reaction time but also on the presence of GO in the nanocomposites. However, the addition of GO did not affect the stoichiometric ratio and the crystal structure of ZnO NRs. The room-temperature PL results indicated that, compared to those of pure ZnO, the luminescence of the GO/ZnO nanocomposites was suppressed and shifted towards a higher wavelength (red shift), which was attributed to the incorporation of ZnO NRs within the GO matrix and the formation of a C-O-Zn chemical bond in the nanocomposites. The hydrothermal technique is considered one of the best routes due to its low cost, high growth rates, low-temperature synthesis, controllable crystallographic orientation, particle size, as well as morphology

Lightweight Heat Resistant Geopolymer-based Materials Synthesized from Red Mud and Rice Husk Ash Using Sodium Silicate Solution as Alkaline Activator

Geopolymer is an inorganic polymer composite with potentials to replace Ordinary Portland Cement (OPC)-based materials in the future because of its lower energy consumption, minimal CO2 emissions and lower production cost as it utilizes industrial waste resources. Hence, geopolymerization and the process to produce geopolymers for various applications like building materials can be considered as green industry. Moreover, in our study, the raw materials we used are red mud and rice husk ash, which are are industrial and agricultural wastes that need to be managed to reduce their impact to the environment. The red mud and rice husk ash combined with sodium silicate (water glass) solution were mixed to form geopolymer materials. Moreover, the geopolymer specimens were also tested for heat resistance at a temperature of 1000°C for 2 hours. Results suggest high heat resistance with an increase of compressive strength after exposed at high temperature