Recently, demands for raw materials like rare earth elements (REEs) have increased considerably due to their high potential applications in modern industry. Additionally, REEs’ similar chemical and physical properties caused their separation to be difficult. Numerous strategies for REEs separation such as precipitation, adsorption and solvent extraction have been applied. However, these strategies have various disadvantages such as low selectivity and purity of desired elements, high cost, vast consumption of chemicals and creation of many pollutions due to remaining large amounts of acidic and alkaline wastes. Membrane separation technology (MST), as an environmentally friendly approach, has recently attracted much attention for the extraction of REEs. The separation of REEs by membranes usually occurs through three mechanisms: (1) complexation of REE ions with extractant that is embedded in the membrane matrix, (2) adsorption of REE ions on the surface created-active sites on the membrane and (3) the rejection of REE ions or REEs complex with organic materials from the membrane. In this review, we investigated the effect of these mechanisms on the selectivity and efficiency of the membrane separation process. Finally, potential directions for future studies were recommended at the end of the review.

Background: One of the underlying mechanisms of Parkinson’s disease is the aggregation of α-synuclein proteins, including amyloids and Lewy bodies in the brain. Aim: To study the inhibitory effect of doped carbon nanotubes (CNTs) on amyloid aggregation. Materials & methods: Molecular dynamics tools were utilized to simulate the influence of CNTs doped with phosphorus, nitrogen and bromine and nitrogen on the formation of α-synuclein amyloid. Results: The CNTs exhibited strong interactions with α-synuclein, with phosphorus-doped CNTs having the most substantial interactions. Conclusion: Doped-CNTs, especially phosphorus-doped carbon nanotube could effectively prevent α-synuclein amyloid formation, thus, it could be considered as a potential treatment for Parkinson’s disease. However, further in vitro and clinical investigations are required.

With the global expansion of industrial activities, the entry of various pollutants into the environment has remained a serious issue. One of the best ways to remove these pollutants is to use the adsorption method. Understanding adsorption mechanisms to improve and optimize adsorbents are pivotal for adsorbent development. In this study, the application of molecular simulation in developing various adsorbents has been reviewed. A variety of molecular simulation methods such as molecular dynamics (MD), density functional theory (DFT), hybrid quantum and classical molecular dynamics (QM/MM), ab initio molecular dynamics (AIMD), and coarse-grained molecular dynamics have been used to study these processes. Although hardware limitations prevented researchers from using this method for real systems, this problem has been solved thanks to the development of computing power units (CPUs) and graphic processing units (GPUs). Due to the increasing use of molecular simulations, an attempt has been made to review previous work in this field. Investigations were conducted on various capabilities of molecular simulations in studying the adsorption process and its limitations. In addition to lowering the cost and time of industrial research, this study advances molecular simulations in academic studies. These simulations can reveal the mechanisms underlying adsorption and the selection, development, and design of suitable adsorbents and adsorption processes. Although investigating the adsorption mechanisms for the selection and design of the process is a complicated problem, this work tends to shed light on almost all types of molecular simulations and their applications in studying the adsorption process of removing various environmental pollutants by various adsorbents.

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Carbon nanoparticles are becoming promising agents in treating Parkinson's disease (PD) by preventing the folding and aggregation of α-synuclein, i.e., amyloid formation. Herein, for the first time, highly tunable graphene and carbon nanotubes (CNTs) have been doped using biocompatible silicon atoms for preventing Parkinson's disease. In this study, the conformational changes induced by these nanoparticles, the compactness of nanoparticles, the number of hydrogen bonds, the stability of α-synuclein in the presence of nanoparticles, and the interaction energies between α-synuclein and nanoparticles were investigated using microsecond coarse-grained and allmolecular-atom simulations. Although the nanoparticles considered in this study could induce desirable changes in α-synuclein conformations, Si-graphene (silicon-doped graphene) demonstrated the best performance. Si-graphene showed the highest interaction energy with α-synuclein compared to other nanoparticles, induced the most hydrogen bonds, was the least compact, and showed the most unstable α-synuclein conformation, resulting in the highest capability to prevent the folding and aggregation of αsynuclein. Our results displayed that 2D hexagonal structures, such as graphene and Si-graphene, possess better performance than tubular structures in inducing conformational changes in the α-synuclein protein. Furthermore, it was observed that the doping of silicon in graphene and CNT results in better folding and aggregation of α-synuclein prevention. This molecular investigation offers a nanostructure method in PD treatment.