Iron‐based magnetic nanoparticles (MNPs) have been studied extensively for the past few decades. They have been applied in various applications, particularly in the biomedical sector. Due to their excellent physical and chemical properties, they have also been used widely in the agricultural sector. MNPs can be synthesized inexpensively and applied in large scale agricultural activities. This paper highlights the applications of iron‐based MNPs in the agricultural sector mainly as antimicrobial agents, plant growth promoters, site‐targeted delivery agents, nanosensors, detection and remediation for pesticide residue. Furthermore, the toxicity and transport of iron‐based MNPs in the soil‐plant system are also elucidated. These aspects have to be well‐understood before MNPs can be fully implemented effectively this pin the agricultural sector. Lastly, a hybrid nanomaterial, which is consisted of iron and magnesium oxide (MgO) nanoparticles (NPs), is proposed. This hybrid nanomaterial is expected to overcome the shortcomings of iron‐based MNPs.

Comprehending and controlling the stability and dissociation of greenhouse gases hydrates are critical for a variety of hydrate-based industrial applications, such as greenhouse gas separation, sequestration, or utilization. Although the promotion effects of greenhouse F-gases (F-promoters) and new cyclic promoters on CO2 hydrates have been acknowledged, the involved molecular mechanisms are poorly understood. This work was therefore conducted to investigate the intermolecular mechanisms of the properties of CO2 and NF3 hydrates using molecular dynamics (MD) simulation to better understand their stability and dissociation and the effects of thermodynamic conditions as well as cage occupancy. In addition, the stability of CO2/CO2 + CH4 hydrates in the presence of seven thermodynamic hydrate promoters (THPs) from different molecular groups or substituents was evaluated. Results reveal that after the breakup of the hydrate, the propensity of NF3 to form nanobubbles is more than that of CO2 molecules. The relative concentration distribution of partially occupied hydrates was also found to be greater than that of completely filled by guest gases. MD simulation results of CO2 double and mixed hydrates also show that the type of large molecular guests in the large cages plays a major role in the stabilization of the clathrate hydrate network. The structural properties, however, indicate that the resistance against being dissociated for CO2 + promoter can be somewhat increased when half of the CO2 molecules in small cages is replaced by CH4. In addition, the existence of neopentyl alcohol in large cavities was found to facilitate the process of hydrate dissociation by making new hydrogen bonds between hydroxyl groups and water molecules. Among studied systems with THPs, cyclopentane, and cyclohexane in comparison with F-promoters seem to be more susceptible to maintaining the stability of CO2 clathrate hydrate.

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The emission of CO2 into the atmosphere is one of the major causes of the greenhouse effect, which has a devastating effect on the environment and human health. Therefore, the reduction of CO2 emission in high concentration is essential. The Rotating Packed Bed (RPB) reactor has gained a lot of attention in post-combustion CO2 capture due to its excellent rate of mass transfer and capture efficiency. To better understand the mechanisms underlying the process and ensure optimal design of RPB for CO2 absorption, elucidating its hydrodynamics is of paramount importance. Experimental investigations have been made in the past to study the hydrodynamics of RPB using advanced imaging and instrumental setups such as sensors and actuators. The employments of such instruments are still challenging due to the difficulties in their installation and placement in the RPB owing to the complex engineering design of the RPB. The hydrodynamics of the RPB can be affected by various operational parameters. However, all of them cannot be evaluated using a single instrumental setup. Therefore, the experimental setups generally result in a partial understanding of the flow behavior in the RPB. The cons and pros of experimental methods are reported and critically discussed in this paper. Computational Fluid Dynamics (CFD), on the other hand, is a powerful tool to visually understand the insights of the flow behavior in the RPB with accurate prediction. Moreover, the different multiphase and turbulence models employed to study the hydrodynamics of RPB have also been reviewed in-depth along with the advantages and disadvantages of each model. The models such as Sliding Mesh Model (SMM) and rotating reference frame model have been adopted for investigating the hydrodynamics of the RPB. The current research gaps and future research recommendations are also presented in this paper which can contribute to fill the existing gap for the CFD analysis of Rotating Packed Bed (RPB) for CO2 absorption.