Volume 33, Issue 2

Currently, few processes can be considered practical alternatives to the use of petroleum for liquid fuel production. Among these alternatives, the Fischer-Tropsch synthesis (FTS) reaction has been successfully applied commercially. Nevertheless, many of the fundamentals of this process are difficult to understand because of its complexity, which depends strongly on the catalyst and the reactor design and operating conditions, as the reaction is seriously affected by mass and heat transport issues. Thus, studying this reaction system with transport phenomena models can help to elucidate the impact of different parameters on the reaction. According to the literature, modeling FTS systems with 1D models provides valuable information for understanding the phenomena that occur during this process. However, 2D models must be used to simulate the reactor to correctly predict the reactor variables, particularly the temperature, which is a critical parameter to achieve a suitable distribution of products during the reaction. Thus, this work provides a general resume of the current findings on the modeling of transport phenomena on a particle/pellet level in a tubular fixed-bed reactor.

Reclamation of wastewater along with minimum energy utilization has been the paramount concern today. Tremendous industrialization and corresponding demographic resulted in elevated water and energy demand; however, scarcity of sufficient water and energy resource triggers rigorous research for sustainable water treatment technology. Recent technologies like activated sludge, filtration, adsorption, coagulation, and oxidation have been considered as promising sustainable technologies, but high cost, low efficiency, and efficacy are the major concerns so far. Wastewater is food for billions of bacteria, where some exceptional bacterial species have the ability to transport electrons that are produced during metabolism to outside the cell membrane. Indeed, wastewater can itself be considered as a prominent candidate to resolve the problem of sustainability. Bioelectrochemical membrane reactor is a promising technology, which is an integration of microbial fuel cell (MFC) to membrane bioreactor (MBR). It promises the benefit of harvesting electricity while biologically treating any type of wastewater to the highest extent while passing wastewater through anaerobic, aerobic, and integrated membrane compartments in successive manner. In this review, we provide critical rethinking to take this idea of integration of MFC-MBR and apply them to produce a fully functional prototype of bioelectrochemical membrane reactor that could be used commercially.

Airlift reactor (ALR) is a promising multiphase reactor for industrial applications. Abundant reports about modifications of the conventional ALR and optimization of their operation conditions for the purpose of performance enhancement have been accumulated in literatures, demanding a review paper to summarize the reactor design modifications and operation condition optimization of the ALR. In this review, the published research findings and results have been summarized. The basic concepts including the ALRs’ conventional design, classification, principles of operation, and characteristic parameters have been analyzed and systematically organized. The updated advances in the ALR design modifications have been reported. In particular, the concepts of the “groveled ALR” solving the scaling up problem in wastewater treatment, large-scale application, and the ALR with the cross-shaped geometry modifier stabilizing and strengthening the reactor were considered. Also, new operation modes and optimal conditions for enhancing the performance of the ALR have also been summed up. Except for conventional gas-driven methods, new driven methods for the ALR, such as mixture emission of the gas and the liquid and gas-inducing impeller, have been introduced. Optimization of operation conditions for the ALR includes varying position of the gas spargers, utilizing elevated pressure reactor, and exploring the impact of operation parameters, such as superficial gas velocity, static liquid level, and fluid properties. Comparisons between conventional ALRs and the modified systems are carried out paying attention to analogies, similarities, and differences. Most of the documented research results are obtained for various reactor designs at a laboratory scale; studies at pilot and full scale are still insufficient, which indicates that universal scale up design rules permitting the ALR design with a high confidence are required.

The emission of carbon dioxide (CO 2 ) into the atmosphere is considered the main cause of global warming. CO 2 is mostly viewed as the principal product associated with the combustion of fossil fuels. One of the emerging studies at the moment is the use polymeric ionic liquids (PILs) for capturing CO 2 from flue gas streams. The objective of this paper is to provide an overview of the various PILs for CO 2 capture. PILs can be used in different processes, including absorption, membrane, and adsorption. In this paper, preparation and synthesis of PILs for various processes are discussed. The paper includes elaboration on using composite, grafted, and blended PILs to achieve a powerful and effective capture mode. The effects of different parameters such as temperature and pressure on CO 2 sorption are also discussed.

Nanostructures are a viable candidate for the construction of simple blood sugar monitoring devices. Electrochemical oxidation based on the immobilization of glucose oxidase (GOx) on carbon nanostructures has paved the way for a modern approach to the determination of glucose levels in blood. Carbon nanotubes (CNTs) exhibit excellent electrical properties, resulting in increased interest in glucose biosensors based on CNTs. Its large surface area and optimum aspect ratio increase the total amount of immobilized biomaterials onto its surface. In this contribution, recent advances in the development of reliable methods to improve the electron-transfer mechanism of GOx in CNT-based glucose biosensors are highlighted. Moreover, mass production and growth mechanism of purified CNTs by chemical vapor deposition were discussed by emphasizing its growth-control aspects.