Amino acid-assisted effect on hydrate-based CO2 storage in porous media with brine.

CO2 storage as hydrates in porous media is a promising method for storing carbon dioxide (CO2). However, the sluggish formation kinetics of hydrates urge the need to focus on the use of additives (promoters) to accelerate hydrate kinetics. This study investigates the effect of amino acid solutions in brine on CO2 hydrate formation and dissociation kinetics in quartz sand particles QS-2 (0.6-0.8 mm) with 38% porosity. The amino acids l-methionine (l-meth), l-isoleucine (l-iso), and l-threonine (l-threo) were studied at 0.2 wt% using an autoclave hydrate reactor at 4 MPa and 274.15 K in the presence and absence of salt (3.3 wt% NaCl) in 100% water saturation. The hydrate dissociation kinetics was studied at a temperature of 277.15 K. These conditions represent the normal seabed temperature range in Malaysia and hence were used for testing CO2 hydrate formation and dissociation kinetics in quartz sand in this study. Further, CO2 hydrate formation and dissociation experiments were conducted with sodium dodecyl sulphate (SDS) and brine systems as standards for comparison. The findings reveal the best kinetics for l-meth exhibiting the highest CO2 hydrate storage capacity. l-meth recorded a gas-to-hydrate conversion ratio of about 93% at 0.2 wt% in quartz sand with brine. Moreover, l-meth exhibited the lowest hydrate dissociation rate compared to l-iso and l-threo systems, thereby enhancing CO2 hydrate stability in quartz sand. Comparatively, l-meth enhanced the storage capacity by 36% and reduced the induction time by more than 50% compared to conventional promoter SDS in quartz sand with brine, suggesting it to be favorable for CO2 storage applications. CO2 hydrate nucleation time was predicted in quartz sand with and without the best-studied amino acid l-meth system with high prediction accuracy and an absolute average deviation of 2.4 hours. The findings of this study substantiate the influence of amino acids in promoting the storage capacity of CO2 in sediments as hydrates.

Printing Parameter Optimization of Additive Manufactured PLA Using Taguchi Design of Experiment.

Three-dimensional printing (3DP), known as additive layer manufacturing (ALM), is a manufacturing process in which a three-dimensional structure is constructed by successive addition of deposited layers. Fused Deposition Modeling (FDM) has evolved as the most frequently utilized ALM process because of its cost-effectiveness and ease of operation. Nevertheless, layer adhesion, delamination, and quality of the finished product remain issues associated with the FDM process parameters. These issues need to be addressed in order to satisfy the requirements commonly imposed by the conventional manufacturing industry. This work is focused on the optimization of the FDM process and post-process parameters for Polylactic acid (PLA) samples in an effort to maximize their tensile strength. Infill density and pattern type, layer height, and print temperature are the process parameters, while annealing temperature is the post-process parameter considered for the investigation. Analysis based on the Taguchi L18 orthogonal array shows that the gyroid infill pattern and annealing cycle at 90 °C results in a maximum ultimate tensile strength (UTM) of 37.15 MPa. Furthermore, the regression model developed for the five variables under study was able to predict the UTS with an accuracy of more than 96%.

Sn-doped BiOCl for photoelectrochemical activities and photocatalytic dye degradation under visible light.

In this work, bismuth oxychloride (BiOCl) and Sn-doped BiOCl (SBCl) with improved visible light photocatalytic activity were synthesized via the co-precipitation method. The XRD analysis determined the tetragonal phase of BiOCl, 1 %, 5 %, and 10 % SBCl. The crystallite sizes were in the range of 20-34 nm. These results confirmed that the Sn ion was successfully incorporated into the BiOCl lattice. This was further confirmed by FT-IR and Raman analysis. The optical properties, such as the band gap energy, were studied using UV-vis DRS. It was found that doping BiOCl with Sn has a minor effect on the band gap tuning. BET shows that the SBCl samples have acquired a larger specific surface area (14.66-42.20 m2/g) than BiOCl (13.49 m2/g). The photocatalytic performance showed that SBCl samples have higher photocatalytic activity than BiOCl in degrading Rhodamine B (RhB) dye under visible light irradiation. Among the SBCl samples, 5 % SBCl exhibited the highest photocatalytic efficiency which degraded 91.2 % of the RhB dye in 60 min. Moreover, the photoelectrochemical activities of the as-synthesized BiOCl and SBCl were investigated using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in the dark and under visible light irradiation. Both studies showed that SBCl exhibits enhanced photoelectrochemical activities than BiOCl. Hence, it can be suggested that SBCl possesses visible light active properties and can be potentially used as a photocatalyst and photoelectrode material.

CO2 Adsorption on Biomass-Derived Carbons from Albizia procera Leaves: Effects of Synthesis Strategies.

CO2 capture is a useful strategy for controlling the risks associated with global warming. The design of an adsorbent is essential for clean and potentially energy-efficient adsorption-based carbon capture processes. This study reports a facile and moderately temperature single-stage combined pyrolysis and activation strategy for the synthesis of nitrogen-doped carbons for high-performance CO2 capture. Using nitrogen-rich Albizia procera leaves as the precursor and carrying out single-stage pyrolysis and activation at temperatures of 500, 600, and 700 °C in the presence NaHCO3 as an activating agent, carbons with different surface characteristics and ultrahigh weight percentage (22-25%) of nitrogen were obtained. The subtle differences in surface characteristics and nitrogen content had a bearing on the CO2 adsorption performance of the resultant adsorbents. Outstanding results were achieved, with a CO2 adsorption capacity of up to 2.5 mmol/g and a CO2 over N2 selectivities reaching 54. The isotherm results were utilized to determine the performance indicators for a practical vacuum swing adsorption process. This study provides a practical strategy for the efficient synthesis of nitrogen-doped carbons for various adsorption applications.

Reticular Chemistry for Optical Sensing of Anions.

In the last few decades, reticular chemistry has grown significantly as a field of porous crystalline molecular materials. Scientists have attempted to create the ideal platform for analyzing distinct anions based on optical sensing techniques (chromogenic and fluorogenic) by assembling different metal-containing units with suitable organic linking molecules and different organic molecules to produce crystalline porous materials. This study presents novel platforms for anion recognition based on reticular chemistry with high selectivity, sensitivity, electronic tunability, structural recognition, strong emission, and thermal and chemical stability. The key materials for reticular chemistry, Metal-Organic Frameworks (MOFs), Zeolitic Imidazolate Frameworks (ZIFs), and Covalent-Organic Frameworks (COFs), and the pre- and post-synthetic modification of the linkers and the metal oxide clusters for the selective detection of the anions, have been discussed. The mechanisms involved in sensing are also discussed.

CO2 Adsorption on Pore-Engineered Carbons Derived from Jute Sticks.

CO2 capture is a practical approach to mitigating the impacts of global warming. Adsorption-based carbon capture is a clean and potentially energy-efficient method whose performance greatly depends on adsorbent design. In this study, we explored the use of jute-derived carbon as a high-performance adsorbent for CO2 capture. The carbons were produced by pyrolyzing powdered jute sticks with NaHCO3 as an activating agent at 500-700 °C. Impressive adsorption capacities of up to 2.5 mmol ⋅ g-1 and CO2 /N2 selectivities of up to 54 were achieved by adjusting the pore size distribution and surface functionalization. Based on the isotherm results, the working capacities, regenerabilities, and potentials for CO2 separation were determined for a practical vacuum swing adsorption process. The adsorbent materials were characterized by XRD, FTIR, Raman, FESEM and N2 sorption at 77 K. This study provides a general approach for designing adsorbents for various gas-separation applications.

Controlled Covalent Functionalization of ZIF-90 for Selective CO2 Capture & Separation.

Mixed Matrix Membranes (MMM) with enhanced selectivity and permeability are preferred for gas separations. The porous metal-organic frameworks (MOFs) materials incorporated in them play a crucial part in improving the performance of MMM. In this study, Zeolitic imidazolate frameworks (ZIF-90) are selected to fabricate Polyetherimide (PEI) MMMs owing to their lucrative structural and chemical properties. This work reports new controlled post-synthetic modifications of ZIF-90 (50-PSM-ZIF-90) with ethanolamine to control the diffusion and uptake of CO2. Physical and chemical properties of ZIF-90, such as stability and presence of aldehyde functionality in the imidazolate linker, allow for easy modulation of the ZIF-90 pores and window size to tune the gas transport properties across ZIF-90-based membranes. Effects of these materials were investigated on the performance of MMMs and compared with pure PEI membranes. Performance of the MMMs was evaluated in terms of permeability of different gases and selective separation of CO2 and H2 gas. Results presented that the permeability of all membranes was in the following order, i.e., P(H2) > P(CO2) > P(O2) > P(CH4) > P(C2H6) > P(C3H8) > P(N2), demonstrating that kinetic gas diffusion is the predominant gas transport mode in these membranes. Among all the membranes, permeability of pure PEI membrane was highest for all gases due to the uniform porous morphology. The pure PEI membrane showed highest permeability of H2, which is 486.5 Barrer, followed by 49 Barrer for O2, 29 Barrer for N2, 142 Barrer for CO2, 41 Barrer for CH4, 40 Barrer for C2H6 and 39.6 Barrer for C3H8. Results also confirm the superiority of controlled PSM-ZIF-90-PEI membrane over the pure PEI and ZIF-90-PEI membranes in CO2 and H2 separation performance. The 50-PSM-ZIF-90 PEI membrane exhibited a 20% increase in CO2 separation from methane and a 26% increase over nitrogen compared to the ZIF-90-PEI membrane. The 50-PSM-ZIF-90 PEI membrane showed 15% more H2/O2 separation and 9% more H2/CH4 separation than ZIF-90 PEI membrane. Overall, this study represents the role of controlled PSM in enhancing the property of new materials like ZIF and its application in MMMs fabrication to develop a promising approach for the CO2 capture and separation.

Zr, La-dual doped silver niobate for photocatalytic degradation of dyes under visible light irradiation.

Sol-gel-assisted synthesis of silver niobate, 1%, 5%, and 10% Zr, La-dual doped silver niobates were carried out. Analysis done using XRD showed that increasing Zr and La dual doping caused the synthesized materials to adopt an AgNbO3-like structure. This is also supported by FT-IR results. FESEM revealed that the silver niobate has a prism-like morphology while Zr, La-dual doped samples are irregular in shape. EDX mapping of the 10% Zr, La dual silver niobate confirmed the presence of Nb, Ag, Zr, and La metals. When compared with the silver niobate, the band gap energy of Zr, La-dual doped silver niobates are narrower, as shown by UV-Vis DRS measurements. It was revealed that dual doping of silver niobates with Zr and La has significantly improved the photocatalytic degradation of methylene blue (MB) and Rhodamine B (RhB) dyes. The 1% Zr, La-dual doped silver niobate showed the best photocatalytic results in terms of degrading MB while 10% Zr, La-dual doped silver niobate achieved the best performance when degrading RhB.

Potential Applications of Nickel-Based Metal-Organic Frameworks and their Derivatives.

Metal-Organic Frameworks (MOFs), a novel class of porous extended crystalline structures, are favored in different fields of heterogeneous catalysis, CO2 separation and conversion, and energy storage (supercapacitors) due to their convenience of synthesis, structural tailor-ability, tunable pore size, high porosity, large specific surface area, devisable structures, and adjustable compositions. Nickel (Ni) is a ubiquitous element extensively applied in various fields of catalysis and energy storage due to its low cost, high abundance, thermal and chemical stability, and environmentally benign nature. Ni-based MOFs and their derivatives provide us with the opportunity to modify different properties of the Ni center to improve their potential as heterogeneous catalysts or energy storage materials. The recent achievements of Ni-MOFs and their derivatives as catalysts, membrane materials for CO2 separation and conversion, electrode materials and their respective performance have been discussed in this review.

Present Status and Future Prospects of Jute in Nanotechnology: A Review.

Nanotechnology has transformed the world with its diverse applications, ranging from industrial developments to impacting our daily lives. It has multiple applications throughout financial sectors and enables the development of facilitating scientific endeavors with extensive commercial potentials. Nanomaterials, especially the ones which have shown biomedical and other health-related properties, have added new dimensions to the field of nanotechnology. Recently, the use of bioresources in nanotechnology has gained significant attention from the scientific community due to its 100 % eco-friendly features, availability, and low costs. In this context, jute offers a considerable potential. Globally, its plant produces the second most common natural cellulose fibers and a large amount of jute sticks as a byproduct. The main chemical compositions of jute fibers and sticks, which have a trace amount of ash content, are cellulose, hemicellulose, and lignin. This makes jute as an ideal source of pure nanocellulose, nano-lignin, and nanocarbon preparation. It has also been used as a source in the evolution of nanomaterials used in various applications. In addition, hemicellulose and lignin, which are extractable from jute fibers and sticks, could be utilized as a reductant/stabilizer for preparing other nanomaterials. This review highlights the status and prospects of jute in nanotechnology. Different research areas in which jute can be applied, such as in nanocellulose preparation, as scaffolds for other nanomaterials, catalysis, carbon preparation, life sciences, coatings, polymers, energy storage, drug delivery, fertilizer delivery, electrochemistry, reductant, and stabilizer for synthesizing other nanomaterials, petroleum industry, paper industry, polymeric nanocomposites, sensors, coatings, and electronics, have been summarized in detail. We hope that these prospects will serve as a precursor of jute-based nanotechnology research in the future.

Sulfone-containing Conjugated Polyimide 2D Nanosheets for Efficient Water Oxidation.

Water oxidation is a bottleneck in artificial photosynthesis that impedes its practicality for solar energy conversion and utilization. It is highly desired to significantly improve the efficacy of the existing catalysts or to rationally design new catalysts with improved performance. We report a novel conjugated and sulfone containing polyimide as a metal-free photocatalyst synthesized via a two-step method: (i) synthesis of precursor poly(amic acid) (PAA) (ii) solvothermal synthesis of polyimide through thermal imidization. The synthesis of the polyimide photocatalyst was demonstrated by the amide linkage in the FTIR spectrum. The obtained photocatalyst was semicrystalline in nature and possessed sheet-like morphology as illustrated by the diffraction pattern and the electron micrographic images, respectively. The thermogravimetric analysis of the polyimide nanosheets validated a thermally stable structure. The DFT calculations were performed which showed a suitable HOMO band position, favorable for water oxidation. The photoelectrocatalytic (PEC) performance of the polyimide nanosheets evaluated by studying water oxidation reaction without any sacrificial agent under 1-SUN showed enhanced PEC performance and good stability towards water oxidation at 0 V versus SCE.

A 2D Graphitic-Polytriaminopyrimidine (g-PTAP)/Poly(ether-block-amide) Mixed Matrix Membrane for CO2 Separation.

Poly(ether-block-amide)/g-PTAP mixed matrix membranes (MMMs) were developed by incorporating different wt.% (1-10%) of a novel 2D g-PTAP nanofiller and its effects on membrane structure and gas permeability were studied. The novel 2D material g-PTAP was synthesized and characterized by various analytical techniques including field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Raman spectroscopy. The fabricated MMMs were investigated to study the interaction and compatibility between Pebax and g-PTAP. The MMMs showed an effective integration of g-PTAP nanofiller into the Pebax matrix without affecting its thermal stability. Gas permeation experiments with MMMs showed improved CO2 permeability and selectivity (CO2 /N2 ) upon incorporation of g-PTAP in the Pebax polymer matrix. The maximum CO2 permeability enhancement from 82.3 to 154.6 Barrer with highest CO2 /N2 selectivity from 49.5 to 83.5 were found with 2.5 wt.% of nanofiller compared to neat Pebax membranes.

Ultrasonically controlled growth of monodispersed octahedral BiVO4 microcrystals for improved photoelectrochemical water oxidation.

The synthesis of facet-controlled structures with precise morphology and exposed reactive surface is one of the key research challenges. We effectively endeavoured to obtain the monodisperse octahedral bismuth vanadate microcrystals with exposed {101},{200},{312} and {021} dominant facets through an optimized sonochemical assisted hydrothermal process. A pulse sonication (5-s ON and 2-s OFF cycle, 21 W ultrasonic power and 20 kHz ultrasonic frequency) for 30 mins followed by 1 h hydrothermal treatment was found to yield the preferred octahedral morphology. The microscopic and X-ray analysis suggested a potent role of ultrasonic waves for the initial seed growth and its evolution into a well-defined monodisperse microcrystals. The density functional theory (DFT) calculations revealed strongly localized bandgap states with a bandgap of ~2.47 eV. The PEC measurements for water oxidation demonstrated the efficacy of these microcrystals as photoanode. Notably, the optimized octahedral BiVO4 microstructure exhibited a superior performance as evident from photocurrent density ~0.9 mAcm-2 at 1.23 V vs. RHE and %IPCE value of ~22% compared to analogous photoanodes under visible light irradiation.

Development of new atom transfer radical polymerization system by iron (III)-metal salts without using any external initiator and reducing agent.

Atom transfer radical polymerization (ATRP) catalyzed by high oxidation state metal salts of FeX3 is developed for the first time in the absence of both external initiator and reducing agent. Methyl methacrylate (MMA) and styrene are polymerized successfully using FeX3 /Phosphorous ligands with well-controlled molecular weight distributions (=1.5). The molecular weight of the polymers increases with monomer consumption with the progress of time and the polymerization behaviors show a decent ATRP trend. Activators and initiators are suggested to generate in situ by the addition reaction of MMA and one equivalent of FeX3 . The PMMA synthesized from without-initiator system is characterized by (1) H, (13) C and DEPT (distortionless enhancement by polarization transfer nuclear magnetic resonance) nuclear magnetic resonance spectroscopy. Chain extension and copolymerization experiments prove the livingness of the obtained polymer.