Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) - Volume 15, Issue 2, 2022

Over the last two decades, Poly(ionic liquid)s (PILs) have undergone extensive research and development. PILs have opened a whole new passage to versatile ionic polymers. It has compelled the chemical industry to rethink its modern ways of carbon capture. PILs have demonstrated excellent CO2 sorption capacities in comparison to their corresponding Ionic Liquids (ILs). The effects of the chemical structures of PILs on CO2 sorption, including the types of anion, cation, and backbone, have been discussed. This review aims to cover details of a large range of PILs along with their physical and structural properties, synthesis procedures, and the absorption power of CO2. Imidazoliumbased PILs are some of the strongest absorbents of CO2. On the other hand, PILs with Amino Acid (AA) anion seem to have a much-improved sorption capacity when compared PILs with the non-AA anionic part. PILs with hexafluorophosphate ion (PF6 -) relatively absorb more CO2 compared to tetra-fluoroborate (BF4 -) based PILs. The solubility of CO2 was increased with increasing pressure and decreased as temperature increased. The inclusion of hydroxyl groups in the polycation increased the interaction with CO2 molecules. The COSMO-RS model was used to understand the molecular-level behavior of PILs in terms of their activity coefficients.

Carbon Dioxide (CO2) capture has been widely accepted to be a prerequisite strategy to mitigate the increase of CO2 concentration in the atmosphere. Membrane separation has been envisaged to be one of the most promising technologies for CO2 capture due to its small footprint, simple up- and down-scaling, and low impact on the environment. Owing to their extraordinary high CO2 permeability and moderate CO2 selectivity over other gases, high free volume polymeric membrane materials have been intensively studied for CO2 capture. In the past few years, abundant high free volume polymers have been developed and big progress has been made in this field. Therefore, in this review, starting from CO2 emissions and sources, followed by CO2 transport mechanisms in polymeric membranes, this paper emphasizes reviewing recent research progress in high free volume membrane materials, collecting and analyzing CO2 separation data, as well as discussing the challenges of high free volume polymeric membranes. Furthermore, perspectives on future directions of high free volume polymeric membranes were also proposed.

Background: Excessive use of fossil energy has exacerbated global warming, and the goal of carbon neutralization has been put on the agenda. In order to make full use of renewable energy and reduce greenhouse gas emissions, it is urgent to develop environment-friendly energy storage devices. We previously reported metal sulfides/ graphene nanocomposites for the applications in supercapacitors (I. NiS/graphene). Recent work was presented as the paper in the series (II. Ni-Mn-S/Mn-Cu-O/graphene). Objective: To synthesize graphene-supported multi-metal sulfides for electrochemical capacitance storage. Methods: The materials were prepared with a two-step hydrothermal method. Samples were characterized by field emission scanning electron microscopy, X-ray powder diffraction, and electrochemical measurements. Results: The as-fabricated electrode exhibited a specific capacitance of 566 F g^–1 at the current density of 1 A g^–1 and a rate of 68% at 10 A g^–1. The materials retained 75.8% of the initial capacitance after 1000 charge-discharge cycles at 5 A g^–1. The results suggest optimum Ni-Mn-S/Mn-Cu-O/graphene composites for supercapacitor applications. Conclusion: The Ni-Mn-S/Mn-Cu-O/graphene composites with nanosheet structures were prepared with a two-step hydrothermal method. The materials showed enhanced electrochemical capacitance performances superior to the individual components.

Objective: To explore the drag reduction effect of surfactant-polymer composite system in a turbulent flow. Methods: The turbulent drag reduction experiment of the one-component solution and the composite solution was carried out in a rectangular pipeline platform, respectively. Moreover, Particle Image Velocimetry (PIV) was utilized to measure the turbulent flow field of the drag-reducing flow. Results: Experimental results show that the composite drag reduction system has a drag reduction gain effect in comparison with the one-component surfactant or polymer solution. Especially in the destroyed drag reduction zone, the composite drag reduction system has a strong shear resistance. When Polyacrylamide (PAM) is added, the Reynolds drag reduction range of Cetyltrimethylammonium Chloride (CTAC) solution is broadened and the drag reduction gain efficiency reaches 46%, which will provide favorable conditions for oil transportation and other industries. Conclusion: Compared with a one-component CTAC solution, the mean velocity distribution of the composite solution moves up in the logarithmic-law layer, the velocity fluctuation peaks of the streamwise direction shift away from the inner wall of pipe, and the inhibition degree of the normal velocity fluctuation increases with the augment of PAM concentration. In contrast with water, the Reynolds shear stress of one-component CTAC solution and composite solution is reduced significantly, and the vortex structures in the region near the wall are suppressed dramatically with the decrease of vorticity intensity.

Introduction: The effects of different physical activation agents on carbon material pore development and the subsequent methane adsorption were studied. Methods: Palm Kernel Shell (PKS) as a carbon precursor was pre-treated with ZnCl2 and activated for two hours with (i) CO2, (ii) steam, and (iii) the combination of CO2 and steam (in series). Results: The findings indicate that the combination of two activation agents in series resulted in a considerably high value of methane uptake of 118.73 V/V at 10 bar. Compared to the activation with a single activating agent (steam or CO2), double activation agents produced Activated Carbon (AC) with a higher BET surface area of 869.8 m2/g and a total pore volume of 0.47 cm³/g. The obtained carbon materials were predominantly microporous, with 92.08% micropores and 7.92% mesopores, respectively. Conclusion: The results show that combining two activation agents with different diffusivity and reactivity significantly affects carbon pore development for methane adsorption.

Aim: The major goal of this fascinating study was to determine the molecular interaction of the polymer dextran with urea in an aqueous media using a more straightforward technique. Background: Many physical approaches play important roles in identifying the molecular structure and molecular characteristics of various solutions. In recent years, advances in ultrasonic methods have become a potent tool for assessing information regarding the physical and chemical behaviour of liquid molecules. Objective: The acoustical parameters like “free volume, internal pressure, absorption coefficient, Rao’s constant, and Wada’s” constant are evaluated from the measured data. The significance gives subjective information on the type and quality of solute-solvent particle interactions in liquid solutions. Methods: Specific gravity bottles, Ostwald's viscometer, and multifrequency ultrasonic interferometer were used to determine the density (ρ), viscosity (η), and ultrasonic speed (U) in binary systems of biopolymer dextran with urea at 313 K. Results: After thoroughly examining the results, a careful study of the findings revealed the link between the solute and the solvent. In the light of solute-solvent and solutesolute interactions, the fluctuation of these parameters with a change in dextran concentration and frequency has been examined. Conclusion: The thermo-acoustic value indicates an atomic interaction in the solution. In the current systems, extremely weak molecular interactions such as solute-solvent, solute- solute, etc., are commonly seen. The structure largely determines the force and type of contact.

The article entitled “Natural Organic Matter (NOM) Transformations and their Effects on Water Treatment Process: A Contemporary Review”, by Karnena et al., published in Recent Innovations in Chemical Engineering 2021; 14(5). https://dx.doi.org/10.2174/2405520415666211229101553 has been retracted on a complaint of plagiarism with a previously published article entitled “Natural organic matter-cations complexation and its impact on water treatment: A critical review” in the journal Water Research 2019, 160, 130-147. 10.1016/j.watres.2019.05.064. The authors were notified of the complaint and were requested to provide justification in their defense. However, they have not responded in this regard. Bentham Science apologizes to the readers of the journal for any inconvenience this may have caused. The Bentham Editorial Policy on Article Retraction can be found at https://benthamscience.com/editorial-policies-main.php. BENTHAM SCIENCE DISCLAIMER: It is a condition of publication that manuscripts submitted to this journal have not been published and will not be simultaneously submitted or published elsewhere. Furthermore, any data, illustration, structure or table that has been published elsewhere must be reported, and copyright permission for reproduction must be obtained. Plagiarism is strictly forbidden, and by submitting the article for publication the authors agree that the publishers have the legal right to take appropriate action against the authors, if plagiarism or fabricated information is discovered. By submitting a manuscript, the authors agree that the copyright of their article is transferred to the publishers if and when the article is accepted for publication.