Recycled polyethylene terephthalate and aluminum anodizing sludge-based boards with flame resistance

Nuclear and morpho-histopathological alterations in Astyanax altiparanae exposed to effluent from the process of anodizing aluminum

Aluminum is a metal widely used from household utensils to civil construction. Anodizing aluminum is a procedure to form a thick layer of aluminum oxide on the surface in order to confer greater resistance to the material. This process generates an effluent with acidic pH and a high concentration of sulfate. Alternatives for the treatment of this effluent involve the use of the chemical precipitation technique, which can be used with salts of barium chloride (BaCl2), calcium chloride (CaCl2), and aluminum hydroxide with commercial limestone (Cc/Al (OH)3). The objective of this study was to evaluate the toxicity of effluents on Astyanax altiparanae (Lambari), by means of somatic, genetic, morphological, and histological markers after 24 and 96 h of exposure. After measuring the biometric data of the animals and the weight of the liver, we found that the condition factor (K) of individuals exposed to the effluent CaCl2 showed a slight reduction in growth after 96 h while the hepatosomatic index (HSI) remained unchanged for all effluents in both sampling times. The micronucleus test with erythrocytes indicated that the raw effluent (E2) induced nuclear changes after 24 h; however, this effect did not persist after 96 h of exposure. Branchial arches were collected and according to Bernet's index for histopathology, all effluents except Cc/Al (OH)3, induced significant changes in the gills. In accordance with the index of Poleksic and Mitrovic-Tutundzic, CaCl2 was the only effluent to compromise branchial operation. The branchial morphology investigated by SEM showed that the raw effluent (E1) induced injuries and compromised gill functions. This study reinforces the importance of biological tests for the assessment and validation of physical chemicals used and effluent treatment techniques as well as the development and application of biological parameters before the wastewater release, whether in a raw state or a treated one.

A Brief Review: Application of Recycled Polyethylene Terephthalate in Asphalt Pavement Reinforcement

Plastic is considered one of the most significant industrial inventions of this era due to its excellent properties, which lend well to many manufacturing applications. These days, there are tons of Polyethylene Terephthalate (PET) waste products that are generated around the world. This waste presents a real environmental hazard because PET is not biodegradable. This paper delineates the physical and chemical properties of PET to justify its use as an additive and aggregate replacement in the manufacture of asphalt mixtures. Furthermore, discusses details of PET-modified asphalt mixture by a dry and wet process with sufficient information to better understand the mixture. Several critical matters are investigated, such as asphalt modification to increase resistance to fatigue, rutting deformation, and moisture sensitivity. These results are important for determining the factors that significantly improve pavement mixture characteristics. The findings show that the addition of PET to asphalt mixtures yielded very promising results. PET enhanced the mechanical properties, the durability, and the long-term sustainability of the pavement. Finally, using PET waste as an additive in asphalt mixtures could serve as an environmentally friendly method to dispose of PET waste while simultaneously producing high-quality pavements.

Performance and Durability of Porous Asphalt Mixtures Manufactured Exclusively with Electric Steel Slags

Electric arc furnace slag (EAFS) and ladle furnace slag (LFS) are by-products of the electric steelmaking sector with suitable properties for use in bituminous mixtures as both coarse and fine aggregates, respectively. In this research, the production of a porous asphalt mixture with an aggregate skeleton consisting exclusively of electric steelmaking slags (using neither natural aggregates nor fillers) is explored. The test program examines the asphalt mixtures in terms of their mechanical performance (abrasion loss and indirect tensile strength), durability (cold abrasion loss, aging, and long-term behavior), water sensitivity, skid and rutting resistance, and permeability. The results of the slag-mixes are compared with a standard mix, manufactured with siliceous aggregates and cement as filler. The porous mixes manufactured with the slags provided similar results to the conventional standard mixtures. Some issues were noted in relation to compaction difficulties and the higher void contents of the slag mixtures, which reduced their resistance to raveling. Other features linked to permeability and skid resistance were largely improved, suggesting that these mixtures are especially suitable for permeable pavements in rainy regions. In conclusion, a porous asphalt mixture was produced with 100% slag aggregates that met current standards for long-lasting and environmentally friendly mixtures.