Key Engineering Materials Vol. 974

Abstract: Several attempts have been made on the use of alternative material for constructionpurpose. This is to limit the exploitation of the natural resources and the need to engage onrenewable resources that can function adequately in road construction with minimal carbonfootprints. The main objective of this review is to consider the outcome of the suitability of wasteglass products in the construction of roads based on the existing studies. From the relevant literatureconsulted, it was discovered that waste glass powder has the capacity to improve the compressiveand tensile strength of asphalt mix. Also, it has lower water absorption rate, thereby making itimpossible for the penetration of the chloride ions which usually accelerate road degradation. Inaddition to this, it improves the workability of the concrete used for the pavement construction,hence, it is more advantageous when compared with sand. The findings from this study will help theconstruction industry on the methods of waste glass recycling and its adoption into roadconstruction.

Abstract: The national decision on the neutrality of global carbon emission as well as decarbonization focus drives the need for the transformation of the building and construction sector of the economy. Thus, green building materials and its production is a better means of achieving depletion in carbon emission. More so, to achieve excellent green development in the construction industry as well as the goal of decarbonization, there is a need to investigate the emerging trends in the sustainable materials for green buildings. Hence, this study focused on the review of some of the existing green materials and its effect on the building construction. Findings from literature studies revealed six different green building materials which include bamboo, cork, straw bale, reclaimed wood, sheep’s wool and hempcrete. It was reported that each of the green material have excellent thermal insulation property, low emission of CO₂ and has the ability to be recycled, thus, bringing sustainability in the circular economy as well as eco-friendliness of the material. These findings expand the scope of green materials application and can inform the government to formulate policies that will encourage sustainable green buildings. Keyword: Sustainability, Development, Green Buildings, Green Materials, Emissions

Abstract: Petroleum industry effluents contain hazardous compounds such as heavy metals, which can damage the environment and human health. In this work, petroleum wastewater used as a medium to culture marine algae Scenedesmus sp. with the aim of removing maximum heavy metals. The efficiency of Scenedesmus sp. were examined in laboratory scale for elimination of COD, BOD and total petroleum heavy metals. The marine algae were monitored in pure petroleum wastewater as well as 25%, 50% and 75% diluted wastewater samples which conducted for 15 days. At the condition of 27 ± 2 °C, Scenedesmus sp. removed 35 – 96% of chromium (IV), cadmium (II) and copper (II). Among them chromium (IV) was significantly removed by Scenedesmus sp. Hence, phytoremediation using Scenedesmus sp. is seen as one of the best options to remove heavy metals from petroleum wastewater. Keywords: Microalgae, Scenedesmus sp., heavy metals, wastewater, biomass

Abstract: The presence of heavy metals in water resources brings hazard to health and the environment considering that most of these cannot be degraded and may result in bioaccumulation in the food chain. This study investigated the applicability and efficiency of waste eggshells for the removal of Copper (Cu) heavy metal in aqueous solution. The mixed-matrix membrane with polyvinylidene fluoride (PVDF) as membrane material, N-Methyl-2-pyrrolidone (NMP) as solvent and waste eggshell as additive with ratio of (a) 15:85:0, (b) 14.9:85:0.1, (c) 14.7:85:0.3, (d) 14.5:85:0.5 and (e) 14:85:1 is fabricated using phase inversion method. Phase inversion is a well-studied immersion precipitation technique for membrane synthesis. Using this common method, polymer is dissolved in an organic solvent and the solution cast upon a glass surface with 0.40 knife gap. The resulting membrane morphologies were analysed by using Scanning Electron Microscopy (SEM) and the significant functional group of the resulting membranes were identified using Fourier Transform Infrared Spectroscopy (FTIR). The addition of waste eggshell to the casting solution improved the morphology and structure of the membrane significantly. The appearance of waste eggshell on membrane surface demonstrated in SEM and FTIR analysis. Furthermore, the result of the study showed that the waste eggshells as an adsorbent could remove Cu in an aqueous solution up to 99% with water permeability of 56.52 Lm^-2h^-1bar^-1. Overall, the study demonstrated that the waste eggshell that is generally considered as wastes in large quantities could become an economically advantageous for Cu removal.

Abstract: The main objective of this study was to characterize and investigate the performance of sodium alginate (SA)-based composite beads as adsorbents for manganese removal from the aqueous solution. In this study, 2% (w/v) of sodium alginate solution was prepared. The SA beads, SA-PCC (SA-P) beads, SA-BMnO (SA-B) beads, and SA-PCC-BMnO (SA-PB) beads were formed by mixing with ionic gelation in a crosslink solution of calcium chloride (CaCl₂). The composite beads were characterized using FESEM and thermogravitmetry analysis (TGA). According to FESEM micrographs, all the adsorbents were spherical in shape, with an average diameter of 1.40 mm to 1.50 mm. The results of TGA demonstrated that SA-PB beads had improved thermal stability and exhibited the highest manganese removal efficiency, with a percentage of removal of 96.14%.

Abstract: In this research, the researchers successfully fabricated photocatalysts hybrid materials using g-C₃N₄ microrods and g-C₃N₄ nanosheets, which were coated on water hyacinth cellulose sponges. The optical properties of the photocatalysts hybrid materials, specifically the g-C₃N₄ microrods and g-C₃N₄ nanosheets, were analyzed using a UV-vis spectrometer. The morphology of the g-C₃N₄ microrods and g-C₃N₄ nanosheets photocatalysts was examined using different procedures, including FTIR (Fourier-transform infrared spectroscopy), XRD (X-ray diffraction), and TEM (transmission electron microscopy). The results obtained from the study indicate that g-C₃N₄ microrods exhibited a higher level of crystallinity or orderliness in terms of intramolecular orientation compared to g-C₃N₄ nanosheets. This suggests that the microrods possessed a more organized arrangement of atoms within the material structure. Furthermore, the energy bandgap values, as determined from the study, were found to be 2.25 eV for the microrods and 2.75 eV for the nanosheets. As part of this project, the photocatalysts, namely g-C₃N₄ microrods and g-C₃N₄ nanosheets, were utilized as coating materials for water hyacinth-synthesized cellulose sponges. This process led to the formation of hybrid materials known as g-C₃N₄ MCS (Microrods Cellulose Sponge) and g-C₃N₄ NCS (Nanosheets Cellulose Sponge). The efficiency and reaction rate of MB removal were then studied with various models such as First order reaction, Second order reaction, Pseudo first order reaction, Pseudo second order reaction and Elovich model. The results obtained from the research project indicated that the g-C₃N₄ NCS hybrid material exhibited a notably higher rate of organic degradation compared to the g-C₃N₄ MCS hybrid material. In conclusion, this research project successfully achieved the fabrication and characterization of a photocatalysts hybrid material using cellulose sponge from water hyacinth. The material demonstrated excellent performance as an absorbent and degradation agent for organic pollutants in water, highlighting its potential for practical applications in water treatment and environmental remediation.

Abstract: The cupric ion is toxic for humans and is contained in many industrial wastewater that should be effectively removed with adsorption before discharging into the natural water source. In this study, pineapple pulp was obtained from canned pineapple juice manufacturing for drying (DPP) and carbonization (CPP) for 2 h. at 400 °C as the fine biochar adsorbents. The specific surface area of DPP and CPP were 45.3 and 60.2 m²/g, respectively. A high surface area of the carbonized pineapple pulp as a fine adsorbent was found to effectively cupric ion adsorption capacity, the maximum cupric ion removal efficiency of 83.4% and 41.9 mg/g of adsorption capacity at a pH of 6.0 was attained after 30 minutes to equilibrium reach, initial feed concentration of copper (II) sulfate 5-hydrate (CuSO₄ ^. 5H₂O) 250 ppm and temperature 50 °C. From these results can be applied to remove the cupric ion from the wastewater treatment.

Abstract: In this century, sustainability has become an essential element in any project to ensure a safe environment. The conversion of waste materials is an important step towards achieving sustainability. Moreover, converting these materials into adsorbents to treat wastewater shows great potential, especially due to its cost-effectiveness and the reduction of solid waste disposal. This research study aims to investigate the removal of Copper (Cu) from wastewater using waste tyre-recycled carbon black (WT-rCB) and modified waste tyre-recycled carbon black (WT-dAC) to determine their adsorption capability. The removal of Copper using WT-rCB and WT-dAC were investigated with various parameters: pH value, adsorbent dosage, and contact time. The chemical-physical activation process was employed to produce the WT-dAC. First, WT-rCB was impregnated with 1:5 wt% of 1 M KOH solution, then physically activated at 650 °C for 1 hr with flowing Nitrogen gas at 1 L/min. The adsorption study observed a removal efficiency of up to 65% using WT-dAC, while WT-rCB showed a removal efficiency of 22% under the optimum conditions. Eventually, the study demonstrates the employability of WT-dAC in the removal of Copper (Cu) from wastewater.

Abstract: This paper aims to investigate the effects of adding and increasing the concentration of halloysite nanotube (HNT) to a cellulose acetate (CA) membrane which is produced through non-solvent-induced phase separation via hand casting. Different characterization tests are performed on the nanocomposite samples: Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared Spectroscopy (FTIR), and Atomic Absorption Spectroscopy (AAS). The addition of the filler itself increases the presence of peaks and valleys on the surface of the nanocomposite membrane. The 5% HNT nanocomposite membrane has the largest peaks and valleys-both in size and number. Using the following contact times: 2, 4, and 6 hours, the adsorption capacity of the CA-HNT membranes is obtained with the aid of AAS results. The 5% HNT sample leads to a nanocomposite membrane with a higher adsorption capacity relative to that of a pure CA membrane.