Monthly Archives: October 2023

Preparation of an Activated Carbon Composite with High Thermal Conductivity Based on Emulsified Asphalt and Carbon Nanotubes and its Adsorption Performance for n‐Hexane

Posted on 11 October 2023 by

The preparation process of composite activated carbon is mainly from stirring, then high temperature sintering to carbon, followed by a large amount of water washing to remove impurities, and finally drying to obtain composite activated carbon. During the high temperature sintering, asphalt is carbonized to form fluffy carbon material, which increases a lot of space for the loading of CNTs.

Abstract

Activated carbon, as the main adsorption material for treating VOCs, has been widely used. To solve the problem of safety hazards in activated carbon adsorption process due to the large amount of heat released, highly thermally conductive composite activated carbon (A-AC/CNTs) was prepared using asphalt and highly thermally conductive carbon nanotubes (CNTs) for thermal conductivity improvement. Uniform dispersion and firm loading of CNTs in the carbon production material were achieved by dispersing carbon nanotubes (CNTs) in the asphalt-in-water emulsion. Experimental results showed that the specific surface area of A-AC/CNTs reached a maximum when the loading of CNTs was 0.5 wt %. Meanwhile, the thermal conductivity increased by 1.5 times compared with the original activated carbon. The adsorption capacity of n-hexane reached the maximum of 2868 mmol ⋅ g⁻¹, and the adsorption capacity increased by 21.41 %. It also maintained good regeneration performance after dynamic adsorption experiments.

Facile Synthesis of Citric Acid Functionalized Fe3O4@Activated Carbon Magnetic Nanocomposite for Efficient Adsorption of Brilliant Green Dye from Wastewater

Posted on 11 October 2023 by

Surface of Citric acid functionalized Fe₃O₄/Activated Carbon behaves as cationic and anionic depending on its point zero charge (pH~8), which lead to various adsorbent-dye interactions. Brilliant green dye shows superior adsorption behaviour near neutral condition as depicted from the plot of dye removal percentage as a function of contact time owing to the surface interactions such as electrostatic interactions and hydrogen bonding.

Abstract

Owing to the impact of brilliant green dye on potable water contamination, citric acid functionalized magnetic nanocomposite in presence of activated carbon was prepared for easy, quick, and efficient removal of the dye from water. Batch adsorption studies were conducted to maximize the adsorption efficiency by optimizing contact time, initial dye concentration, pH, dosage, and salt concentration. The maximum efficiency of the citric acid functionalized Fe₃O₄@activated carbon was found to be 773 mg g⁻¹. The efficiency of the monolayer adsorption process as depicted from the Langmuir model is explained based on the hydrogen bonding, electrostatic interaction, and porosity of the adsorbent. The adsorption process follows a pseudo-second order kinetics model which can also be correlated to the relatively quick adsorption process. The saturation magnetization of the nanocomposites prepared in presence of activated carbon was found to be 35.2 emu/g, which makes it effective for quick magnetic separation. Built on the findings, we report an economical, efficient, and satisfactory alternative adsorbent for the abatement of brilliant green dye from coloured wastewater and contaminated water sources.

3D‐Printed TiO2 Electrode as a Viable Alternative for Photoelectrocatalytic Purification of Water

Posted on 11 October 2023 by

Ti-TiO₂ nanotube photoelectrodes manufactured via sintering of commercial pure titanium powder (cp-Ti), followed by anodization, has equivalent characteristics and photoelectrocataytic performance for treatment of organic compounds compared to photoelectrode produced from commercial titanium foil. Using the 3D-printed electrode, the photoelectrocatalysis has showed as a viable advanced oxidation alternative for the treatment of Benzothiazole. Results allow exploration of innovative electrode designs.

Abstract

A commercial pure titanium (cp-Ti) powder was used to produce a photoelectrode substrate via 3D-printing and a commercial titanium foil (Ti-foil) was used as substrate for direct comparison. TiO₂ nanotubes were prepared on both Ti substrates via electrochemical anodization. Characterisation of electrodes showed similar results in all aspects analysed: morphology, absorbance, crystallinity, and photo-current response. The efficiency of photoelectrocatlytic treatment of methylene blue dye (MB) in water with a single-chip UVA-LED was identical. The cp-Ti/TiO₂ electrode achieved 93±4 % removal of MB after 210 min, when combined with a four-chip UVA-LED. The cp-Ti photoelectrode was also tested for the first time for photoelectrocatalytic treatment of benzothiazole (BTH). The highest degradation of BTH (98±2 %, 120 min) was also achieved using the four-chip UVA-LED. This study supports further development of 3D-printed electrodes, maximizing the potential for the creation of novel electrodes for use in PEC technologies for abatement of organic pollutants.

Synthesis of Novel Polycyclic Alkylated Tetralin Base Oils Catalyzed by Ionic Liquids and Its Lubricating Properties

Posted on 11 October 2023 by

At low temperatures, an efficient synthesis of polycyclic alkylated compounds by tetralin and 1,7-octadiene using Et₃NHCl−AlCl₃ ionic liquid has been developed. The polycyclic alkylated tetralin with high viscosity has excellent tribological properties, which provides a new route for the production of high viscosity lubricating base oils from coal-based feedstocks.

Abstract

A novel polycyclic alkylated tetralin (PAT) similar to the naphthenic oil was successfully synthesized through Friedel-Crafts alkylation. This was accomplished by reacting coal-based chemical tetralin with 1,7-octadiene, using Et₃NHCl−AlCl₃ ionic liquid as a catalyst. To enhance the selectivity towards dialkylated products (C28−2THN), the reaction conditions were systematically studied. Interestingly, the reaction could proceed well even at a low temperature of 0 °C and the selectivity for C28−2THN products could reach 54.0 %. The primary physicochemical properties of PAT were investigated in detail, it was found that the existence of polycyclic structures contributes to high viscosity, better thermal-oxidative stability and good polarity. Compared with octyltetralins- and commercial alkylnaphthalene-based oil (AN30), the PAT exhibited superior friction-reducing and anti-wear properties under the load of 100 N at 50 °C due to its rigid cycle structures and flexible chain.

Selective Electrophoretic Deposition of Silicon Nanoparticles onto PAN‐Based Carbon Fiber as a Prospective Anode for Structural Li‐Ion Batteries

Posted on 11 October 2023 by

New class of batteries is needed as the traditional ones are heavyweight, limiting their applications in some areas. Structural battery can be a solution as it provides both mechanical and electrochemical functions simultaneously. This work presents the potential of silicon-modified PAN-based carbon fiber as prospective anode for structural Li-ion batteries, which was obtained via facile and cheap electrophoretic deposition method.

Abstract

The demand for revolutionizing the lightweight design of Li-ion batteries has become inevitable due to the ever-increasing development of electric transportation modes. Integration of structural and energy storage functionalities into a single structural battery device can be a smart way to improve the overall performance of electric vehicles. In this study, we propose a facile and cost-effective approach to develop a prospective anode for structural Li-ion batteries through electrophoretic deposition of silicon (Si) particles onto polyacrylonitrile (PAN)-based carbon fiber. The synthesis method is able to selectively deposit small-sized silicon particles on the surface of carbon fiber, producing a thin, continuous, and porous coating of silicon nanoparticles on commercial PAN-based carbon fiber. The synthesized Si/PAN-based carbon fiber electrode exhibits remarkable mechanical properties, delivering a tensile strength of 2.57 GPa and a tensile modulus of 118.2 GPa. Benefitting from the morphology of the deposited silicon, the discharge capacity of silicon/PAN-based carbon fiber anode can reach 565 mAh g⁻¹ with 81 % capacity retention after 50 cycles. This work highlights the potential of silicon-modified carbon fiber electrodes obtained via a simple and cost-effective deposition method for structural Li-ion battery applications.

Prussian Blue and Its Analogues: From Properties to Biological Applications

Posted on 11 October 2023 by

A set of studies have demonstrated the properties of PB and its analogues such as photothermal ability, reactive oxygen species scavenging and adsorption ability. Many outstanding researches are published to set a basis for further application in clinic. The properties and biological applications of PB as well as its analogue are reviewed, and hope arouse more interests of researchers.

Abstract

The utilization of metal organic framework (MOF) nanocomposites in various biomedical applications has been widely studied because of their unique properties. In recently years, Prussian blue (PB) is widely used in clinical studied due to its biosafety, which has already been approved by USA Food and Drug Administration (FDA). Therefore, it is great urgent to systematically summarize the resent progress to better serve the broad community of researchers. This review focuses on the properties of PB and PB analogues (PBA), and their applications in biological field. A systemic introduction of the properties is presented, including abilities of photothermal, scavenging of reactive oxygen species and adsorption. A variety of biomedical applications, such as tumor therapy, anti-bacterial infection, biosensor, bioimaging, excretion, ischemic stroke treatment, etc. have been discussed as well. Furthermore, the challenges, key factors, and the prospects in the clinical transformation of PB or PBA are simultaneously discussed. This review will provide reference and guidance for the design and application of PB and PBA in the future.

Preparation and Utilization of a Comb‐Like Polycarboxylate Dispersant for Organic Pigment

Posted on 11 October 2023 by

A series of carboxylate comb-like copolymer dispersants, SAM-(m)PEG, were synthesized via polymerization and esterification to disperse and stabilize C.I. Pigment Yellow 180 (PY 180). Among them, SAM-PEG600₂ displayed the best performance; the average particle size (Z-average) and PDI of PY 180 could reach 264.6 nm and 0.089, respectively, when applied. Furthermore, the results of the optical property experiments demonstrated the versatile applicability of SAM-PEG600₂.

Abstract

As a novel form of carboxylate comb-like copolymers, SAM-(m)PEG was prepared by polymerizing styrene (S), acrylic (A), and maleic anhydride (M) to obtain a random copolymer labeled SAM. SAM was then esterified using either polyethylene glycol (PEG) or methyl PEG (mPEG), a waterborne polymer dispersant for dispersing and stabilizing C.I. Pigment Yellow 180 (PY 180). The structures of SAM-(m)PEG and the ground suspension of PY 180 were characterized by Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy (SEM), a nanoparticle size analysis, and viscometry. The effects of different branch chains, synthetic formulas, and grinding conditions on the dispersibility of SAM-(m)PEG were evaluated. In addition, the optical properties of the pigments were investigated after ultrafine grinding. The adsorption mechanism between the SAM-(m)PEG dispersants and PY 180 particles is also discussed. SAM-PEG600₂ outperformed the other SAM-(m)PEG dispersants owing to its excellent dispersion and stability. When used as the dispersant, the average particle size (Z-average) of PY 180 after grinding was 264.6 nm, and the particle size distribution became narrow (PDI=0.089). Moreover, SAM-PEG600₂ effectively maintained the color performance of the pigment, and the product was successfully applied to the pigment coating. Therefore, SAM-PEG600₂ is an effective waterborne polymer dispersant for organic pigments.

Understanding Critical Aspects of Liposomal Synthesis for Designing the Next Generation Targeted Drug Delivery Vehicle

Posted on 11 October 2023 by nAliesha Moudgil, nBhushan P. Chaudharin

We optimized multiple process paramters and certain intrinsic factors to develop liposomes for drug delivery; liposomes were also characterized by various analytical techniques. This study provides a mechanistic insight into the synthesis method, ascertains roles to every factor, and allows modification of appropriate parameters to synthesize liposomes with desired specifications.

Abstract

We identified process parameters of the thin film hydration technique and intrinsic factors to synthesize liposomes for drug delivery. The thin film formation step impacted the nature of the lipid layer, and we optimized 240 RPM rotation speed, 700 mm of Hg vacuum pressure, and 2 ml of chloroform as the organic solvent. The hydration step controlled the particle specifications, and we optimized 270 RPM rotation speed, PBS as the hydrating medium, and 1 h hydration time. We obtained a comparatively smaller liposomal population with a lower size distribution just after hydrating the lipid layer that required milder downsizing steps −10 extrusion passes through a single polycarbonate membrane. The intrinsic factors including the concentrations and molar ratio of lipids affected the synthesis steps and the particle specifications. Characterization of liposomes by analytical techniques confirmed the synthesis of a monodisperse population with hydrodynamic diameter<150 nm, moderate stability, spherical morphology, and high thermal and storage stability. This comprehensive study defines the role of every parameter, provides a mechanistic insight into synthesis that is supported by experimental data, and helps tune specific parameters to synthesize liposomes for drug delivery or any application with desired specifications.

Enhanced Yield of Sodium Alginate Extracted from Padina gymnospora Using a Greener Microwave and Ultrasound Hybrid System

Posted on 11 October 2023 by nSwabiiha Buxoo, nHareenanden Ramasawmy, nPratima Jeetahn

A high yield of sodium alginate with high mannuronic content and low viscosity was extracted by using a greener and cleaner organic acid pre-treatment in the presence of the eco-friendly microwave and ultrasound techniques for a sustainable extraction route.

Abstract

In this study, alginate was extracted from Padina gymnospora (PG) by applying the sequential combination of microwaves followed by ultrasounds (at low power and amplitude settings) using an organic acid pre-treatment. The optimum alginate yield was investigated by varying the type of acid (oxalic and formic) and seaweed particle size range (0.295–0.495 and 0.146–0.246 mm). The extracted sodium alginate was then characterised in terms of FTIR, ¹H-NMR, M/G ratio, viscosity and colour. The synergistic effect of the microwave-ultrasound hybrid system for short timeframes (15 min each) successfully improved the alginate yield without compromising its structural composition, while allowing for a milder and greener organic acid to be used for the acid pre-treatment. The highest alginate yield (~64 %) was obtained using formic acid and the smaller particle size range (0.146–0.246 mm). The latter thus highlights the importance of particle size reduction and optimisation. FTIR, NMR and viscosity analyses revealed a low guluronic acid content of alginate with a high M/G ratio (7.7±1.0–9.3±0.1) and low viscosity (2.92±0.09–3.05±0.06 cP), which was found to be inherent to the species used. The proposed novel method therefore opens prospects for the industry since it is both environmentally and economically sustainable.

One‐Pot Synthesis of β‐Ketoesters from Aryl Methyl Ketone via Ketene Dithioacetal

Posted on 11 October 2023 by

Activated methylene group-containing compound was synthesized from functionalized acetophenone through ketene dithioacetals using ethanolic KOH.

Abstract

We have discovered base-mediated conversion of 3,3-bis(methylthio)-1-arylprop-2-en-1-ones to versatile active methylene compounds (β-keto esters). A series of products were isolated and characterized as a mixture of keto-enol form. We have modified the method and synthesized the active methylene compounds (β-keto esters) directly from aryl methyl ketone via ketene dithioacetal intermediate (not isolated) by stepwise reactions in one pot. Most of the one-pot reactions also provided excellent yields. In addition to aryl methyl ketones, we also tested cyclopropyl methyl ketone as a source of an aliphatic ketone, and under similar reaction conditions, ethyl 3-cyclopropyl-3-oxopropanoate was afforded.