Performance of Cathodes Fabricated from Mixture of Active Materials Obtained from Recycled Lithium-Ion Batteries

The cathode performance of lithium-ion batteries (LIBs) fabricated from recycled cathode active materials is studied for three scenarios. These scenarios are based on the conditions for separation of different cathode active materials in recycling facilities during the LIB’s recycling process. In scenario one, the separation process is performed ideally, and the obtained pure single cathode active material is used to make new LIBs after regeneration. In scenario two, the separation of active materials is performed with efficiencies of less than 100%, which is the actual case in the recycling process. In this scenario, a single cathode active material that contains a little of the other types of cathode active materials is used to make new LIBs after the materials’ regeneration. In scenario three, the separation has not been performed during the recycling process. In this scenario, all types of cathode active materials are regenerated together, and a mixture is used to make new LIBs. The studies are performed through modeling and computer simulation, and several experiments are conducted for validation purposes. The cathode active materials that are studied are the five commercially available cathodes made of LiMn2O4 (LMO), LiCoO2 (LCO), LiNixMnyCo(1−x−y)O2 (NMC), LiNixCoyAl(1−x−y)O2 (NCA), and LiFePO4 (LFP). The results indicate that the fabrication of new LIBs with a mixture of cathode active materials is possible when cathode active materials are not ideally separated from each other. However, it is recommended that the separation process is added to the recycling process, at least for the separation of LFP or reducing its amount in the cathode active materials mixture. This is because of the difference of the voltage level of LFP compared to the other studied active materials for cathodes.

Sintering Behavior and Hardness of Tungsten Prepared by Hard Metal Sludge Recycling Process without Ammonium Paratungstate

In this paper, we suggest a novel recycling process for hard metal sludge that does not use ammonium paratungstate. Ammonia, which in the conventional recycling process is essential for removing sodium and crystallized tungstate, was not used in the novel process. Instead of ammonia, acid was used to remove the sodium and crystallized tungstate resulting in the formation of tungstic acid (H2WO4). Tungsten powders were successfully synthesized by hydrogen reduction of the tungstic acid through H2O decomposition, WO3 to WO2 reduction, and tungsten metal formation. The tungsten powders prepared from tungstic acid were spherical in shape and had a higher sintering density than the facet-shaped tungsten powders prepared from tungsten oxide. The spherical shape of the tungsten powders enhanced their sinterability and resulted in an increase in the size of grains. This is a result of the high diffusion rate of the atoms along the particle surfaces. Despite having a higher density, the hardness of the sintered tungsten was lower than that of tungsten from tungsten oxide. High energy milling effectively reduced grain size and improved hardness. The hardness of the tungsten prepared from milled tungstic acid was enhanced to a value (max. 471 HV) higher than the best previously reported value (389 HV). In sum, tungsten can be hardened, thereby improving its sinterability and reducing grain size, with tungstic acid prepared using the proposed recycling process.

Endosomal Recycling Defects and Neurodevelopmental Disorders

The quality and quantity of membrane proteins are precisely and dynamically maintained through an endosomal recycling process. This endosomal recycling is executed by two protein complexes: retromer and recently identified retriever. Defects in the function of retromer or retriever cause dysregulation of many membrane proteins and result in several human disorders, including neurodegenerative disorders such as Alzheimer’s disease and Parkinson´s disease. Recently, neurodevelopmental disorders caused by pathogenic variants in genes associated with retriever were identified. This review focuses on the two recycling complexes and discuss their biological and developmental roles and the consequences of defects in endosomal recycling, especially in the nervous system. We also discuss future perspectives of a possible relationship of the dysfunction of retromer and retriever with neurodevelopmental disorders.

Pretreatment of Plastic Waste: Removal of Colorants from HDPE Using Biosolvents

Plastics recycling remains a challenge due to the relatively low quality of the recycled material, since most of the developed recycling processes cannot deal with the additives present in the plastic matrix, so the recycled products end up in lower-grade applications. The application of volatile organic solvents for additives removal is the preferred choice. In this study, pretreatment of plastic packaging waste to remove additives using biosolvents was investigated. The plastic waste used was high-density polyethylene (HDPE) with blue and orange colorants (pigment and/or dye). The first step was to identify the type of colorants present in the HDPE, and we found that both plastics presented only one colorant that was actually a pigment. Then, limonene, a renewable solvent, was used to solubilize HDPE. After HDPE dissolution, a wide range of alcohols (mono-, di-, and tri-alcohols) was evaluated as antisolvents in order to selectively precipitate the polymer and maximize its purity. The use of limonene as solvent for plastic dissolution, in combination with poly-alcohols with an intermediate alkyl chain length and a large number of hydroxyl (OH) groups, was found to work best as an antisolvent (1,2,3-propanetriol and 1,2,4-butanetriol), leading to a removal of up to 94% and 100% of the blue and orange pigments, respectively. Finally, three cycles of extraction were carried out, proving the capability of the solvent and antisolvent to be recovered and reused, ensuring the economic viability and sustainability of the process. This pretreatment provides a secondary source of raw materials and revenue for the recycling process, which may lead to an increase in the quality of recycled polymers, contributing to the development of an economical and sustainable recycling process.

A Novel Recycling Route for Spent Li-Ion Batteries

In this work, a recycling route for spent Li-ion batteries (LIBs) was developed. For this, the recovery of the metal content in both electrodes (anode and cathode) was investigated. Based on these results, an economic analysis of this recycling process was carried out. The obtained results showed that more than 90% of the material contained in both electrodes was recycled. The dissolution with acetic acid of the metals present in the active cathodic material is thermodynamically viable and the addition of a reducing agent such as hydrogen peroxide improved the spontaneity of the reaction. Dissolutions close to 100% for Li and Co were obtained. In addition, it was determined that the synthesis of lithium and cobalt valuable compounds was viable from the leach liquor, recovering approximately 90% of Co as cobalt oxalate, and 92% of Li as lithium carbonate. Furthermore, carbon graphite and Cu were fully recovered (100%) from the anodes. Finally, the results of the economic analysis showed that the recovered products have a high commercial value and industrial interest, providing an environmentally and economically viable process.

A Persistence Search for the Most Appropriate Process of PET Recycling: A Review

One of the most serious threats to the environment in today’s world is plastic pollution. The reason for widespread of plastic is its poor disposal management, indiscriminate use of plastic and its related products. There was a tremendous increase in the production of plastic from the start of 21st century due to its high demand which tripled the waste in these two decades. This review papers aims at providing the understanding of various techniques used for PET plastic degrading process and currently used in large scale that is quite detrimental to the environment. Further, the recent discovery of the bacteria eating enzyme provided a shaft of light in waste green recycling process. Adding to this, there is an outline provided for bioengineering of the most preferred enzymes for hydrolysis process result is compared that which one is more efficient one. Comparing them and trying to exploring the potential of various mutated enzymes for hydrolyzing of plastic waste formulated by various researchers to identify the Nobel PET catalyst which can solve the massive environment crisis when used in large-scale.

ASSESSMENT OF THE DEGREE AND SOURCE OF POLYOLEFIN RECYCLATES CONTAMINATION

This study has the aim of analysing the degree of contamination of recycled polyolefin purchased from the market by focusing on the content of polycyclic aromatic hydrocarbons (PAHs). Additionally, the impact of the mechanical recycling process on the polyolefin chemical quality was investigated. Results indicated that recycled polyethylene (PE) had higher PAHs concentrations by 10 to 20 folds in comparison to the pristine PE. Similarly, recycled polypropylene (PP) indicated higher PAHs concentrations in comparison to the virgin polypropylene, yet with lower degree of difference. Analysing the 8 indicators assigned by the Regulation EU 1272/2013 amending REACH Annex XVII, all recycled specimens showed concentrations lower than the limit of 0.5 mg kg-1, which indicates that there is no restriction in material’s utilisation. This study functioned as a preliminary assessment to check the suitability of recycled plastics for their further utilisation. Additionally, the study indicates that polyolefin can experience quality deterioration when uncontrolled recycling conditions are applied.