On the Low-Pressure Hysteresis (LPH) in Gas Sorption Isotherms of Porous Carbons.

This study investigates the origin of low-pressure hysteresis (LPH) in the adsorption and desorption of three different probe molecules: carbon dioxide, nitrogen, and argon, across various adsorption temperatures (from cryogenic to room temperature), and within five different carbon materials: synthetic carbons (pristine and one post-synthetically oxidized) and natural coal. Significant attention is dedicated to elucidating LPH in oxidized samples outgassed at various temperatures (120-350 °C). Experimental results show that insufficient outgassing temperature can lead to unreliable data due to artificial LPH and significantly underestimated textural properties, primarily caused by porosity blockage from substances like moisture.

Carbonaceous Materials Porosity Investigation in a Wet State by Low-Field NMR Relaxometry.

The porosity of differently wetted carbonaceous material with disordered mesoporosity was investigated using low-field 1H NMR relaxometry. Spin−spin relaxation (relaxation time T2) was measured using the CPMG pulse sequence. We present a non-linear optimization method for the conversion of relaxation curves to the distribution of relaxation times by using non-specialized software.

Liquefaction of Cellulose for Production of Advanced Porous Carbon Materials.

Cellulose is a renewable resource for the production of advanced carbonaceous materials for various applications. In addition to direct carbonization, attention has recently been paid to the preparation of porous carbons from liquid cellulose-based precursors. Possible pathways of cellulose conversion to a liquid state suitable for the preparation of porous carbons are summarized in this review.

Revisiting the Effect of Pyrolysis Temperature and Type of Activation on the Performance of Carbon Electrodes in an Electrochemical Capacitor.

Hierarchical porous carbons are known to enhance the electrochemical features of electrodes in electrochemical capacitors. However, the contribution of surface oxygen and the resulting functionalities and wettability, along with the role of electrical conductivity and degree of amorphous or crystalline nature in the micro-mesoporous carbons, are not yet clear. This article considers the effect of carbonisation temperature (500-900 °C) and the type of activation (CO, KOH) on the properties mentioned above in case of carbon xerogels (CXs) to understand the resulting electrochemical performances.

Kinetics of Resorcinol-Formaldehyde Condensation-Comparison of Common Experimental Techniques.

Porous carbons, originated from resorcinol-formaldehyde (RF) gels, show high application potential. However, the kinetics and mechanism of RF condensation are still not well described. In this work, different methods (dynamic light scattering-DLS, Fourier transform infrared spectroscopy-FTIR, low field H nuclear magnetic resonance relaxometry-H-NMR, and differential scanning calorimetry-DSC) were used to follow the isothermal RF condensation of mixtures varying in catalyst content (NaCO) and reactant concentration.

Synthesis of Magnetic Adsorbents Based Carbon Highly Efficient and Stable for Use in the Removal of Pb(II) and Cd(II) in Aqueous Solution.

In this study, two alternative synthesis routes for magnetic adsorbents were evaluated to remove Pb(II) and Cd(II) in an aqueous solution. First, activated carbon was prepared from argan shells (). One portion was doped with magnetite () and the other with cobalt ferrite ().

Highly-efficient removal of Pb(ii), Cu(ii) and Cd(ii) from water by novel lithium, sodium and potassium titanate reusable microrods.

In this work, we report on the efficient removal of heavy metal ions with nanostructured lithium, sodium and potassium titanates from simulated wastewater. The titanates were obtained a fast, easy and cost effective process based on extraction of sulfate ions from the crystals of titanyl sulfate and their replacement with hydroxyl groups of NaOH, LiOH and KOH solutions leaving the Ti-O framework intact. The as-prepared titanates were carefully examined by scanning and transmission electron microscopy.

The role of the oxygen functional groups in adsorption of copper (II) on carbon surface.

The effect of carbon surface oxidation on the adsorption of Cu(II) ions from aqueous solution was studied in order to explain the role of the oxygen functional groups in the binding of copper ions. Pristine carbonaceous adsorbent was oxidized to a various extent of oxygen uptake (Fenton-like oxidation < persulphate in HSO < HO in HNO). Equilibrium adsorption tests were performed in acetate buffer at pH ≈ 5.

Determination of the Surface Oxidation Degree of the Carbonaceous Materials by Quantitative TG-MS Analysis.

The developed quantitative TG-MS analysis was used for the determination of the surface oxidation degree of activated carbon cryogels. The surface chemistry of a prepared carbon cryogels pyrolyzed at 400 and 500 °C was modified using HPO, Fenton-like reaction, (NH)SO with HSO and HNO with HO into a different surface oxidation degree. The influence of activation method and the amount of oxygen surface groups were characterized by elemental analysis, immersion calorimetry, water vapor adsorption, and Boehm titration.