Fabrication of a Covalent Triazine Framework Functional Interlayer for High-Performance Lithium–Sulfur Batteries

The shuttling effect of polysulfides is one of the major problems of lithium–sulfur (Li–S) batteries, which causes rapid capacity fading during cycling. Modification of the commercial separator with a functional interlayer is an effective strategy to address this issue. Herein, we modified the commercial Celgard separator of Li–S batteries with one-dimensional (1D) covalent triazine framework (CTF) and a carbon nanotube (CNT) composite as a functional interlayer. The intertwined CTF/CNT can provide a fast lithium ionic/electronic transport pathway and strong adsorption capability towards polysulfides. The Li–S batteries with the CTF/CNT/Celgard separator delivered a high initial capacity of 1314 mAh g−1 at 0.1 C and remained at 684 mAh g−1 after 400 cycles−1 at 1 C. Theoretical calculation and static-adsorption experiments indicated that the triazine ring in the CTF skeleton possessed strong adsorption capability towards polysulfides. The work described here demonstrates the potential for CTF-based permselective membranes as separators in Li–S batteries.

Research and application of natural zeolite in the processes of gas purification and drying

This article describes the adsorption capability of natural zeolites for the purification and dehydration of natural gases. Studies were carried out with natural clinoptilolite treated with various cadmium and titanium solutions. Zeolite-containing rocks were used as a natural adsorbent and experiments using a synthetic CaA zeolite were also carried for comparison. The experiments showed that zeolite from the Ai-Dag deposits possesses the highest activity in terms of sulfur compound. Its activity is closer to that of synthetic CaA zeolite. Studies showed that natural zeolites and adsorbents obtained on their basis allow the gas to be dehydrated to a dew point temperature of minus 40-45 °C. This is sufficient to prepare gas for transportation directly from the fields under any climatic conditions. Keywords: gas dehydration; zeolite; adsorbent; sulfur compounds.

Facile and Sustainable Modification for Improving the Adsorption Ability of Sugarcane Bagasse Towards Cationic Organic Pollutants

Using low-cost agro-industrial wastes and by-products derived from lignocellulosic biomass for adsorption is believed to an affordable and sustainable way to tackle the burning issue of cationic pollution in the marine, while its relatively low adsorption capability limits its large-scale application. Chemical modifications to improve the adsorption abilities of lignocellulosic biomass usually has problems such as long reaction time, high operational cost, rigorous reaction conditions (high temperature and pressure) as well as the second pollution. In this study, a green, rapid, simple, and mild method was developed by using ozone to improve the adsorption abilities of sugarcane bagasse (SB). The effects of ozone modification on the SB and its related adsorption abilities towards cationic polymers were quantitatively investigated. Results showed that ozone modification under very low ozone consumption (~ 1.5 wt%) could efficiently increase the carboxyl groups, change the chemical compositions of SB, and does not significantly change its morphology, thereby ensuring the good recovery and adsorption performance of SB. The maximum adsorption rate and capacity of SB for positively charged methylene blue (MB) were increased about 33.3% and 11.3% than the original SB. Besides, ozone modified SB maintained its high adsorption capability even at high NaCl concentration (0.6 M). For cationic polymer with high charge densities, the adsorption capacity of milled SB increased about 125.4%.

Fabrication of Highly Microporous Structure Activated Carbon via Surface Modification with Sodium Hydroxide

The aim of this study was to select the optimal conditions for the carbonization process followed by surface modification treatment with sodium hydroxide (NaOH) to obtain a highly microporous activated carbon structure derived from palm kernel shells (PKS) and coconut shells (CS). The effects of the carbonization temperature and NaOH concentration on the physiochemical properties, adsorption capability, specific surface area, surface morphology, and surface chemistry of PKS and CS were evaluated in this study. The results show that surface-modified activated carbons presented higher surface area values (CS: 356.87 m2 g−1, PKS: 427.64 m2 g−1), smaller pore size (CS: 2.24 nm, PKS: 1.99 nm), and larger pore volume (CS: 0.34 cm3 g−1, PKS: 0.30 cm3 g−1) than the untreated activated carbon, demonstrating that the NaOH surface modification was efficient enough to improve the surface characteristics of the activated carbon. Moreover, surface modification via 25% NaOH greatly increases the active functional group of activated carbon, thereby directly increasing the adsorption capability of activated carbon (CS: 527.44 mg g−1, PKS: 627.03 mg g−1). By applying the NaOH post-treatment as the ultimate surface modification technique to the activated carbon derived from PKS and CS, a highly microporous structure was produced.

Adsorption of Carbon Dioxide by Metal Organic Framework for Indoor Air Quality Enhancement

Air pollution has become a severe environmental issue among millions of people around the globe. However, the risk of exposure to indoor air pollution is much higher than outdoor air pollution. The most effective way to improve indoor air quality (IAQ) by reducing the indoor CO2 content is by capturing and storing. There are several types of adsorbents used to capture CO2, namely physical adsorbents and chemical adsorbents. Metal-Organic Framework (MOF) is one of the recent interests arising physical adsorbents which possesses high adsorption capability. In this study, MOFs fabricated with different metals and organic ligands were used to evaluate their performance in CO2 adsorption under an enclosed office space. Magnesium, chromium, and copper metals were used as the main element in the MOF fabrication coupled with trimesic acid as an organic ligand. The MOFs’ morphologies generally illustrated that magnesium MOF exhibited a dispersed nanorod flask crystal, chromium MOF showed agglomeration crystal, whereas fine crystal rod was observed in copper MOF. The elemental analysis from EDX and XRD confirmed that the metals were successfully embedded with the organic ligand, which is similar to the literature studies. The CO2 gas adsorption study suggested that magnesium MOF fabricated with trimesic acid possess superior CO2 adsorption capability as the recorded CO2 concentration reduced from 960 ± 73 ppm to 895 ± 57 under 2 hours continuous sampling time. The CO2 adsorption study reveals that the magnesium MOF with trimesic acid ligand yields a promising result on indoor CO2 concentration reduction. This result suggested that the MOF possesses a great potential to be applied in the indoor air quality enhancement with the integration to the existing air purification and/or filtration system.

Highly efficient and robust noble-metal free bifunctional water electrolysis catalyst achieved via complementary charge transfer

The operating principle of conventional water electrolysis using heterogenous catalysts has been primarily focused on the unidirectional charge transfer within the heterostructure. Herein, multidirectional charge transfer concept has been adopted within heterostructured catalysts to develop an efficient and robust bifunctional water electrolysis catalyst, which comprises perovskite oxides (La0.5Sr0.5CoO3–δ, LSC) and potassium ion-bonded MoSe2 (K-MoSe2). The complementary charge transfer from LSC and K to MoSe2 endows MoSe2 with the electron-rich surface and increased electrical conductivity, which improves the hydrogen evolution reaction (HER) kinetics. Excellent oxygen evolution reaction (OER) kinetics of LSC/K-MoSe2 is also achieved, surpassing that of the noble metal (IrO2), attributed to the enhanced adsorption capability of surface-based oxygen intermediates of the heterostructure. Consequently, the water electrolysis efficiency of LSC/K-MoSe2 exceeds the performance of the state-of-the-art Pt/C||IrO2 couple. Furthermore, LSC/K-MoSe2 exhibits remarkable chronopotentiometric stability over 2,500 h under a high current density of 100 mA cm−2.

The Reuse of Industrial By-Products for the Synthesis of Innovative Porous Materials, with the Aim to Improve Urban Air Quality

This works concerns the characterization and the evaluation of adsorption capability of innovative porous materials synthesized by using alginates and different industrial by-products: silica fume and bottom ash. Hydrogen peroxide was used as pore former to generate a porosity able to trap particulate matter (PM). These new materials are compared with the reference recently proposed porous SUNSPACE hybrid material, which was obtained in a similar process, by using silica fume. Structural, morphological, colorimetric and porosimetric analyses were performed to evaluate the differences between the obtained SUNSPACE typologies. The sustainability of the proposed materials was evaluated in terms of the Embodied Energy and Carbon Footprint to quantify the benefits of industrial by-products reuse. Adsorption tests were also performed to compare the ability of samples to trap PM. For this aim, titania suspension, with particles size about 300 nm, was used to simulate PM in the nanoparticle range. The results show that the material realized with bottom ash has the best performance.