Mesoporous Manganese Oxide/Lignin-Derived Carbon for High Performance of Supercapacitor Electrodes.

This study explores the modification of lignin with surfactants, which can be used as a template to make mesoporous structures, and can also be used in combination with manganese oxide to produce manganese oxide/lignin-derived carbon. Organosolv extraction, using ethanol (70%) at 150 °C, was carried out to extract lignin from oil palm wood. Lignin was then mixed with Pluronic F-127, with and without Mn(NO3)2, and then crosslinked with acidic formaldehyde, resulting in a carbon precursor-based modified lignin. Carbonization was carried out at 900 °C to produce lignin-derived carbon and manganese oxide/lignin-derived carbon. The characterization materials included Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope-energy dispersive X-ray (SEM-EDX) mapping, X-ray diffraction (XRD), and N2-sorption analysis. FTIR curves displayed the vibration bands of lignin and manganese oxide. SEM images exhibited the different morphological characteristics of carbon from LS120% (lignin with a Pluronic surfactant of 120%) and LS120%Mn20% (lignin with a Pluronic of 120% and Mn oxide of 20%). Carbon LS120% (C-LS120%) showed the highest specific surface area of 1425 m2/g with a mean pore size of 3.14 nm. The largest mean pore size of 5.23 nm with a specific surface area of 922 m2/g was exhibited by carbon LS120%-Mn20% (C-LS120%-Mn20%). C-LS120%Mn20% features two phases of Mn oxide crystals. The highest specific capacitance of 345 F/g was exhibited by C-LS120%-Mn20%.

Lignin Refinery Using Organosolv Process for Nanoporous Carbon Synthesis.

Porous carbon has been widely used for many applications e.g., adsorbents, catalysts, catalyst supports, energy storage and gas storage due to its outstanding properties. In this paper, characteristics of porous carbon prepared by carbonization of lignin from various biomasses are presented. Various biomasses, i.e., mangosteen peel, corncob and coconut shell, were processed using ethanol as an organosolv solvent. The obtained lignin was characterized using a Fourier transform infrared (FTIR) spectrophotometer and a viscosimeter to investigate the success of extraction and lignin properties. The results showed that high temperature is favorable for the extraction of lignin using the organosolv process. The FTIR spectra show the success of lignin extraction using the organosolv process because of its similarity to the standard lignin spectra. The carbonization process of lignin was performed at 600 and 850 °C to produce carbon from lignin, as well as to investigate the effect of temperature. A higher pyrolysis temperature will produce a porous carbon with a high specific surface area, but it will lower the yield of the produced carbon. At 850 °C temperature, the highest surface area up to 974 m2/g was achieved.

Ethylene Adsorption Using Cobalt Oxide-Loaded Polymer-Derived Nanoporous Carbon and Its Application to Extend Shelf Life of Fruit.

Suppressing the amount of ethylene during storage has been of interest as a method to enhance shelf life of fruit. In this work, ethylene removal by adsorption using cobalt oxide-impregnated nanoporous carbon has been studied. Nanoporous carbon with a high surface area up to 2400 m2 g-1 was prepared by carbonization process biomass and synthetic polymer at 850 °C. Dispersion of cobalt oxide on porous carbon surface was carried out by an incipient wetness procedure followed by calcination process at 200 °C. Ethylene adsorption test was performed using a volumetric method in an ultrahigh vacuum rig constructed by Swagelok VCR® fittings. The results showed that the cobalt oxide/carbon system had significant ethylene adsorption capacity. Ethylene uptake increases with the increasing cobalt oxide loading on the carbon. The highest ethylene capacity of 16 mol kg-1 adsorbent was obtained by using 30 wt.% (weight percentage) of cobalt oxide dispersed in polymer-derived carbon. In closed storage, the ratio of 15 g adsorbent/kg fruit may extend the storage life up to 12 d, higher than that without adsorbent (3 d). Therefore, the results demonstrate the great potential use of cobalt oxide-impregnated nanoporous carbon as an adsorbent for ethylene removal during storage of fruit.

Reusable adsorbent of magnetite in mesoporous carbon for antibiotic removal.

This study aims to evaluate the feasibility of an innovative reusable adsorbent through adsorption-degradation sequence for antibiotic removal from water. The magnetite/mesoporous carbon adsorbent was prepared using a two-step method of (i) in situ impregnation of magnetite precursor during resorcinol formaldehyde polymerization and (ii) pyrolysis at elevated temperature (800 °C). XRD spectra confirmed that magnetite (Fe3O4) was the only iron oxide species present in the adsorbent, and thermogravimetric analysis revealed that its content was 10 wt%. Nitrogen sorption analysis showed that Fe3O4/carbon features a high fraction of mesopores (> 80 vol.%) and a remarkable specific surface area value (246 m2 g-1), outstanding properties for water treatment. The performance of the adsorbent was examined in the uptake of three relevant antibiotics. The maximum adsorption uptakes were ca. 76 mg g-1, ca. 70 mg g-1, and ca. 44 mg g-1 for metronidazole, sulfamethoxazole, and ciprofloxacin, respectively. All adsorption curves were successfully fitted with Langmuir equilibrium model. The regeneration of adsorbent was carried out using Fenton oxidation under ambient conditions. After three consecutive runs of adsorption-regeneration, Fe3O4/carbon maintained its performance almost unchanged (up to 95% of its adsorption capacity), which highlights the high reusability of the adsorbent.

Efficacy of modified carbon molecular sieve with iron oxides or choline chloride-based deep eutectic solvent for the separation of CO2/CH4.

It is necessary to separate CO2 from biogas to improve its quality for the production of biomethane. Herein, an improvement in the separation of CO2/CH4via adsorption was achieved by modifying the surface of CMS. The surface modification of CMS was performed by impregnation with metal oxide (Fe3O4) and N-doping (DES-[ChCl:Gly]). Subsequently, the efficacy of the surface-modified CMS was investigated. This involved CMS modification, material characterization, and performance analysis. The uptake of CO2 by CMS-DES-[ChCl:Gly] and CMS-Fe3O4 was comparable; however, their performance for the separation of CO2/CH4 was different. Consequently, CMS-DES-[ChCl:Gly] and CMS-Fe3O4 exhibited ca. 1.6 times enhanced CO2 uptake capacity and ca. 1.70 times and 1.55 times enhanced CO2/CH4 separation, respectively. Also, both materials exhibited similar repeatability. However, CMS-DES-[ChCl:Gly] was more difficult to regenerate than CMS-Fe3O4, which is due to the higher adsorption heat value of the former (59.5 kJ).

Radioiodination of Modified Porous Silica Nanoparticles as a Potential Candidate of Iodine-131 Drugs Vehicle.

There are challenges related to cancer treatment, namely, targeting and biocompatibility associated with a drug vehicle. This research aims to prepare a theranostic cancer vehicle based on porous silica nanoparticles (PSN) with controllable nanoparticle size, supporting targeting properties, and biocompatible. The synthesis method combined the Stöber process and liquid crystal templating using a dispersant and pore expander. Triethanolamine (TEA) and Pluronic F-127 were combined as a steric stabilizer and dispersing agent, while n-hexane was used as a pore expander. The amine functionalization was carried out using the 3-aminopropyl-triethoxysilane solution. Furthermore, radiolabeling of PSN using Iodine-131 and iodogen as oxidizing agents was carried out. The results showed that the best achievable PSN size was 100-150 nm with a polydispersity index of 0.24 using TEA-Pluronic F-127. The functionalization results did not significantly affect the radioiodination result. Radiochemical purity (RCP) values up to 95% were obtained in the radioiodination, while the labeled compounds were relatively stable with 12 mCi radioactivity, indicating the absence of radiolysis. The synthesized PSN was not toxic to normal cell samples up to a concentration of 150 µg/mL for PSN and 170 µg/mL for PSN-NH2. The cellular uptake testing results of the PSN-131I in cancer cell samples showed promising uptake ability.

Oxygen-enriched surface modification for improving the dispersion of iron oxide on a porous carbon surface and its application as carbon molecular sieves (CMS) for CO2/CH4 separation.

The separation of CO2/CH4 can be enhanced by impregnating porous carbon with iron oxide. Dispersion of iron oxide is one of the critical factors which supports the separation process performance. Iron oxide dispersion can be enhanced by enriching the oxygen functional groups on the carbon surface. This study investigates three distinct oxidation processes: oxidation with a 10% H2O2 solution, ozonation with distilled water, and ozonation with a 10% H2O2 solution. The research steps included the following: (i) oxidation, (ii) impregnation of iron oxide followed by calcination, (iii) material characterization, and (iv) material performance analysis. Materials were characterized using N2 sorption analysis, X-ray diffraction analysis (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy analysis (SEM-EDX), and Fourier transform infrared analysis (FT-IR). Iron oxide was well dispersed on the carbon surface, as evidenced by the elemental mapping of materials. In addition, the oxygen functional groups increased significantly in the range of 28.6-79.7% following the oxidation process, as indicated by the elemental component using SEM-EDX analysis. The impregnation of iron oxide on oxidized carbon ozonated with distilled water (COA-Fe) obtained a maximum CO2 uptake capacity of 3.0 mmol g-1 and CO2/CH4 selectivity increased by up to 190% at a temperature of 30 °C and pressure of 1 atm. Furthermore, the enhancement of CO2/CH4 separation up to 1.45 times was the best performance achieved by COA-Fe. Thus, improving iron oxide dispersion on oxidized carbon surfaces has a potential application in CO2/CH4 separation.

Improving the Separation of CO2/CH4 Using Impregnation of Deep Eutectic Solvents on Porous Carbon.

The separation of CO2/CH4 using porous carbon can be increased by the presence of a functional group of nitrogen on the carbon surface. This study explores the potential of porous carbon derived from the palm kernel shell (C-PKS) impregnated with a deep eutectic solvent (DES), which is one of the chemicals containing a nitrogen element. The DES was composed of a quaternary ammonium salt of choline chloride (ChCl) and a hydrogen bond donor of alcohol. Three alcohols of 1-butanol (-ol), ethylene glycol (-diol), and glycerol (-triol) were employed to study the effects of a number of hydroxyl groups in the separation performance. The research steps included (i) the preparation of DES-impregnated porous carbon synthesized from the palm kernel shell (DES/C-PKS), (ii) characterization of the material, and (ii) a separation test of CO2/CH4 with a breakthrough system. Materials were characterized using scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX), N2-sorption analysis, and Fourier transform infrared (FTIR) spectroscopy. SEM images showed a significant morphological difference of pristine carbon and DES/C-PKS. There was a significant decrease in the range of 67-73% of a specific surface area with respect to pristine carbon, having initially 800 m2/g. However, the N element on the carbon surface increased after impregnation treatment, which was shown from the intensity of the FTIR graphs and EDX analysis. Adsorption isotherm revealed that DES/C-PKS could enhance up to 1.6 times the adsorption capacity of CO2 at 1 atm and 30 °C while increasing the selectivity of CO2/CH4 up to 125%. The breakthrough experiment showed that all DES/C-PKS materials displayed a better performance for the separation of CO2/CH4, indicated by a longer breakthrough time and enhancement of CO2 uptake. The best separation performance was achieved by DES/C-PKS using glycerol as a hydrogen bond donor with 15.4 mg/g of CO2 uptake or equivalent to 95% enhancement of the uptake capacity compared to pristine porous carbon. Also, the cycling test revealed that DES/C-PKS can be used repetitively, which further highlights the efficiency of the material for the separation of CO2/CH4.

Pretreatment technologies for anaerobic digestion of lignocelluloses and toxic feedstocks.

Several feedstocks for anaerobic digestion (AD) have challenges that hamper the success of AD with their low accessible surface area, biomass recalcitrance, and the presence of natural inhibitors. This paper presents different types of pretreatment to address those individual challenges and how they contribute to facilitate AD. Organosolv and ionic liquid pretreatments are effective to remove lignin without a significant defect on lignin structures. To deal with accessible surface area and crystallinity, comminution, steam explosion, pretreatment using N-methyl-morpholine-N-oxide methods are suggested. Moreover, solid extraction, simple aeration, and biological treatments are capable in removing natural inhibitors. Up to date, methods like comminution, thermal process, and grinding are more preferable to be scaled-up.

Improving control of carbide-derived carbon microstructure by immobilization of a transition-metal catalyst within the shell of carbide/carbon core-shell structures.

Carbon materials for electrical energy devices, such as battery electrodes or fuel-cell catalysts, require the combination of the contradicting properties of graphitic microstructure and porosity. The usage of graphitization catalysts during the synthesis of carbide-derived carbon materials results in materials that combine the required properties, but controlling the microstructure during synthesis remains a challenge. In this work, the controllability of the synthesis route is enhanced by immobilizing the transition-metal graphitization catalyst on a porous carbon shell covering the carbide precursor prior to conversion of the carbide core to carbon. The catalyst loading was varied and the influence on the final material properties was characterized by using physisorption analysis with nitrogen as well as carbon dioxide, X-ray diffraction, temperature-programmed oxidation (TPO), Raman spectroscopy, SEM and TEM. The results showed that this improved route allows one to greatly vary the crystallinity and pore structure of the resulting carbide-derived carbon materials. In this sense, the content of graphitic carbon could be varied from 10-90 wt % as estimated from TPO measurements and resulting in a specific surface area ranging from 1500 to 300 m2·g-1.