One-Step Synthesis of Sulfur-Doped Nanoporous Carbons from Lignin with Ultra-High Surface Area, Sulfur Content and CO Adsorption Capacity.

Lignin is the second-most available biopolymer in nature. In this work, lignin was employed as the carbon precursor for the one-step synthesis of sulfur-doped nanoporous carbons. Sulfur-doped nanoporous carbons have several applications in scientific and technological sectors.

Direct Ink 3D Printing of Porous Carbon Monoliths for Gas Separations.

Additive manufacturing or 3D printing is the advanced method of manufacturing monolithic adsorbent materials. Unlike beads or pellets, 3D monolithic adsorbents possess the advantages of widespread structural varieties, low heat and mass transfer resistance, and low channeling of fluids. Despite a large volume of research on 3D printing of adsorbents having been reported, such studies on porous carbons are highly limited.

Understanding the Adsorption of Rare-Earth Elements in Oligo-Grafted Mesoporous Carbon.

Rare-earth elements (REEs) are 17 elements of the periodic table primarily consisting of lanthanides. In modern society, the usage of REEs is ubiquitous in almost all modern gadgets and therefore efficient recovery and separation of REEs are of high importance. Selective adsorption and chelation of REEs in solid sorbents is a unique and sustainable process for their recovery.

Elucidating the mechanisms of Paraffin-Olefin separations using nanoporous adsorbents: An overview.

Light olefins are the precursors of all modern-day plastics. Olefin is always mixed with paraffins in the time of production, and therefore it needs to be separated from paraffins to produce polymer-grade olefin. The state-of-the-art separation technique, cryogenic distillation, is highly expensive and hazardous.

Adsorption of Rare Earth Elements onto DNA-Functionalized Mesoporous Carbon.

The recovery and separation of rare earth elements (REEs) are of national importance owing to the specific usages, high demand, and low supply of these elements. In this research, we have investigated the adsorption of rare earth elements onto DNA-functionalized mesoporous carbons with a BET surface area of 605 m/g and a median mesopore width of 48 Å. Three types of single-stranded DNA, one with 100 base units of thymine, another with 20 units of thymine, and the third, a 2000 unit long DNA from salmon milt were grafted on the carboxylated mesoporous carbon surface.

Electrospun, flexible and reusable nanofiber mat of graphitic carbon nitride: Photocatalytic reduction of hexavalent chromium.

Nanofiber mat of graphitic carbon nitride (g-CN) was fabricated from g-CN/polyvinylidene fluoride (PVDF) composite using an electrospinning technique. The mat was characterized with SEM, AFM, XRD, FTIR and photoluminescence (PL) spectroscopy. This nanofiber mat is flexible and can be folded or rolled without losing any structural integrity.

Soft-Templating of Sulfur and Iron Dual-Doped Mesoporous Carbons: Lead Adsorption in Mixtures.

Lead pollution in drinking water is one of the most common problems worldwide. In this research, sulfur and iron dual-doped mesoporous carbons are synthesized by soft-templating with sulfur content 4.4-6.

Synthesis of Nitrogen and Sulfur Codoped Nanoporous Carbons from Algae: Role in CO Separation.

Nitrogen and sulfur codoped and completely renewable carbons were synthesized from two types of algae, and without any additional nitrogen fixation reaction. The type of activation agents, char-forming temperature, activation agent-to-char ratio, and activation temperature were all varied to optimize the reaction conditions for this synthesis. The maximum Brunauer-Emmett-Teller surface area and total pore volumes of the carbons were 2685 m/g and 1.

Photocatalytic and photo-fenton activity of iron oxide-doped carbon nitride in 3D printed and LED driven photon concentrator.

We have synthesized iron oxide doped carbon nitride with 0.5 to 2 wt.% iron oxide and characterized by XPS, TGA, FTIR, SEM, photoluminescence spectroscopy and photoelectrochemical measurements.

One-step conversion of agro-wastes to nanoporous carbons: Role in separation of greenhouse gases.

Highly microporous carbons have been synthesized from four types of agro-wastes of lignin, walnut shells, orange peels and apricot seeds by one-step carbonization/activation with potassium hydroxide (KOH) in varying ratios. The resultant carbons demonstrated BET specific surface areas of 727-2254 m/g, and total pore volumes 0.34-1.

Nanoporous Boron Nitride as Exceptionally Thermally Stable Adsorbent: Role in Efficient Separation of Light Hydrocarbons.

In this work, nanoporous boron nitride sample was synthesized with a Brunauer-Emmett-Teller (BET) surface area of 1360 m/g and particle size 5-7 μm. The boron nitride was characterized with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and electron microscopy (TEM and SEM). Thermogravimetric analysis (TGA) under nitrogen and air and subsequent analysis with XPS and XRD suggested that its structure is stable in air up to 800 °C and in nitrogen up to 1050 °C, which is higher than most of the common adsorbents reported so far.

Noncompetitive and Competitive Adsorption of Heavy Metals in Sulfur-Functionalized Ordered Mesoporous Carbon.

In this work, sulfur-functionalized ordered mesoporous carbons were synthesized by activating the soft-templated mesoporous carbons with sulfur bearing salts that simultaneously enhanced the surface area and introduced sulfur functionalities onto the parent carbon surface. XPS analysis showed that sulfur content within the mesoporous carbons were between 8.2% and 12.

Postextraction Separation, On-Board Storage, and Catalytic Conversion of Methane in Natural Gas: A Review.

In today's perspective, natural gas has gained considerable attention, due to its low emission, indigenous availability, and improvement in the extraction technology. Upon extraction, it undergoes several purification protocols including dehydration, sweetening, and inert rejection. Although purification is a commercially established technology, several drawbacks of the current process provide an essential impetus for developing newer separation protocols, most importantly, adsorption and membrane separation.

A study on the cytotoxicity of carbon-based materials.

With an aim to understand the origin and key contributing factors towards carbon-induced cytotoxicity, we have studied five different carbon samples with diverse surface area, pore width, shape and size, conductivity and surface functionality. All the carbon materials were characterized with surface area and pore size distribution, X-ray photoelectron spectroscopy (XPS) and electron microscopic imaging. We performed cytotoxicity study in Caco-2 cells by colorimetric assay, oxidative stress analysis by reactive oxygen species (ROS) detection, cellular metabolic activity measurement by adenosine triphosphate (ATP) depletion and visualization of cellular internalization by TEM imaging.

Biocompatibility of soft-templated mesoporous carbons.

Soft-templated mesoporous carbon is morphologically a non-nano type of carbon. It is a relatively newer variety of biomaterial, which has already demonstrated its successful role in drug delivery applications. To investigate the toxicity and biocompatibility, we introduced three types of mesoporous carbons with varying synthesis conditions and pore textural properties.

Studies on supercapacitor electrode material from activated lignin-derived mesoporous carbon.

We synthesized mesoporous carbon from pre-cross-linked lignin gel impregnated with a surfactant as the pore-forming agent and then activated the carbon through physical and chemical methods to obtain activated mesoporous carbon. The activated mesoporous carbons exhibited 1.5- to 6-fold increases in porosity with a maximum Brunauer-Emmett-Teller (BET) specific surface area of 1148 m(2)/g and a pore volume of 1.

Sustainable mesoporous carbons as storage and controlled-delivery media for functional molecules.

Here, we report the synthesis of surfactant-templated mesoporous carbons from lignin, which is a biomass-derived polymeric precursor, and their potential use as a controlled-release medium for functional molecules such as pharmaceuticals. To the best of our knowledge, this is the first report on the use of lignin for chemical-activation-free synthesis of functional mesoporous carbon. The synthesized carbons possess the pore widths within the range of 2.

Tetrahydrofuran-induced K and Li doping onto poly(furfuryl alcohol)-derived activated carbon (PFAC): influence on microstructure and H2 sorption properties.

We have doped poly(furfuryl alcohol)-derived activated carbon (PFAC) with two alkali metals, potassium (K) and lithium (Li), by previously reacting the metals with naphthalene in the presence of tetrahydrofuran (THF), followed by introducing them to pristine PFAC. The THF molecule causes a minor alteration of the microstructure of PFAC as confirmed by Raman spectra, X-ray diffraction, and pore textural analysis. Raman spectra and X-ray diffraction indicated a slight localized ordering toward the stacking defects of disordered carbon, as in PFAC, which can be attributed to the movement of THF molecules within the internal planes of graphene sheets.

Hydrogen confinement in carbon nanopores: extreme densification at ambient temperature.

In-situ small-angle neutron scattering studies of H(2) confined in small pores of polyfurfuryl alcohol-derived activated carbon at room temperature have provided for the first time its phase behavior in equilibrium with external H(2) at pressures up to 200 bar. The data were used to evaluate the density of the adsorbed fluid, which appears to be a function of both pore size and pressure and is comparable to the density of liquid H(2) in narrow nanopores at ∼200 bar. The surface-molecule interactions responsible for densification of H(2) within the pores create internal pressures that exceed the external gas pressure by a factor of up to ∼50, confirming the benefits of adsorptive storage over compressive storage.

Hydrogen adsorption on Pd- and Ru-doped C60 fullerene at an ambient temperature.

Palladium- and ruthenium-doped C(60) fullerene compounds were synthesized by incipient wetness impregnation of C(60) fullerene with the corresponding metal acetylacetonate precursors. Transmission electron microscopy (TEM) imaging of the metal-doped C(60) fullerene samples showed different dispersion morphologies of palladium and ruthenium particles on the C(60) matrix. Raman spectra revealed a drastic decrease in peak intensity followed by disappearance of several bands indicating the distortion of the C(60) cage structure.

Adsorption equilibrium and kinetics of fluoride on sol-gel-derived activated alumina adsorbents.

Adsorption equilibrium and kinetics of fluoride on a sol-gel-derived activated alumina and its modifications with calcium oxide or manganese oxide were studied to explore the feasibility of applying these adsorbents for fluoride removal from drinking water. The activated alumina adsorbents were characterized with SEM/EDS and N(2)-adsorption for their chemical and pore textural properties. The adsorption isotherms were correlated with the Langmuir and Freundlich adsorption equations.

Ammonia adsorption and its effects on framework stability of MOF-5 and MOF-177.

Ammonia adsorption equilibrium and kinetics on MOF-5 and MOF-177 were measured volumetrically at 298 K and ammonia pressures up to 800 torr. This study allowed us to determine the ammonia adsorption properties and stability of both MOFs after exposure to ammonia. MOF-177 adsorbed more ammonia than MOF-5 at ammonia pressures below 150 torr and the ammonia adsorption capacity on both MOFs at 800 torr was about the same (12.

Adsorption equilibrium and kinetics of CO2, CH4, N2O, and NH3 on ordered mesoporous carbon.

Ordered mesoporous carbon was synthesized by a self-assembly technique and characterized with TEM, Raman spectroscopy, and nitrogen adsorption/desorption for its physical and pore textural properties. The high BET specific surface area (798 m(2)/g), uniform mesopore-size distribution with a median pore size of 62.6 Å, and large pore volume (0.

Accelerated formation of THF-H2 clathrate hydrate in porous media.

Porous media were used to control the hydrogen clathrate particle size in order to accelerate its formation kinetics. Stoichiometric tetrahydrofuran-hydrogen binary clathrate hydrates with approximately 1 wt % hydrogen loading formed in the mesopores of four porous media with median pore diameters of 49, 65, 100, and 226 A at 270 K and hydrogen pressure of 65 bar. The minimum formation time for the tetrahydrofuran-hydrogen binary clathrate hydrates was 27 min in a porous medium with a median pore diameter of 49 A, which is 6-22 times faster than the tetrahydrofuran-hydrogen binary clathrate hydrates formed in the bulk ice.

Adsorption of CO(2), CH(4), N(2)O, and N(2) on MOF-5, MOF-177, and zeolite 5A.

Adsorption equilibrium and kinetics of CO(2), CH(4), N(2)O, and N(2) on two newly discovered adsorbents, metal-organic frameworks MOF-5 and MOF-177 and one traditional adsorbent, zeolite 5A were determined to assess their efficacy for CO(2), CH(4), and N(2)O removal from air and separation of CO(2) from CH(4) in pressure swing adsorption processes. Adsorption equilibrium and kinetics data for CO(2), CH(4), N(2)O, and N(2) on all three adsorbents were measured volumetrically at 298K and gas pressures up to 800 Torr. Adsorption equilibrium capacities of CO(2) and CH(4) on all three adsorbents were determined gravimetrically at 298 K and elevated pressures (14 bar for CO(2) and 100 bar for CH(4)).