Sustainable Porous Carbon Research Articles

From waste to resource: Transforming Kraft black liquor into sustainable porous carbon fillers for radome applications

The study addresses environmental and commercial challenges posed by weak black liquor (WBL) generated through the Kraft process in the paper industry. WBL, a toxic waste, annually reaches a staggering 1.3 billion tonnes globally. Currently, it is either incinerated for energy production or subjected to costly and complex chemical treatments to extract valuable compounds. Despite efforts to develop a scalable value-added material, the existing methods are inefficient in fully reusing WBL. Here, we report a simple chemical synthesis process that reuses 100 % of WBL without generating any waste materials; even salts recovered during the process might be reintegrated into the industry as chemical byproducts. Furthermore, given the simplicity and efficiency of the proposed synthesis methodology to transform WBL into a novel and sustainable porous carbon material, the carbon Kraft (CK). The process can also be scaled by using the right synthesis proportions and within a circular economy. CK exhibited desirable characteristics with a renewable content of 65 wt%, including a turbostratic graphitic-like structure (48.8 % graphitized), carbon content of 85 wt%, large specific surface area of 234.0 m2∙g−1, nanoporosity of 0.13 cm3∙g−1, and density of 1.92 g∙(cm3)-1. Moreover, CK showed electrical and thermal insulating characteristics, essential for use as fillers for elastomeric composite in electromagnetic transparent radome structures used to protect antennas and radars of unmanned aerial vehicles (UAV) from harsh environmental effects. Radomes were designed through the electromagnetic impedance match theory of half-wavelength calculations over specific frequencies of 1.3, 10, 15, 20, and 30 GHz. Results showed excellent transmission loss between −0.41 and −1.48 dB, representing 90.8 % and 70.5 % of transmittance, respectively.

Development of activated sustainable porous carbon adsorbents from Karanja shell biomass and their CO2 adsorption

Development of activated sustainable porous carbon adsorbents from Karanja shell biomass and their CO2 adsorption

Efficient removal of methylene blue via two-step modification hazelnut shell biochar: Process intensification, kinetics and thermodynamics

Porous carbon materials with ultra-high specific surface area and adjustable pore structure characteristics were prepared from food industry waste hazelnut shells for the adsorption of methylene blue (MB) wastewater by two-step activation by impregnation with ZnCl2 followed by chemical activation with KOH. The Fusso effect, which can reduce the size of MB molecules, was further used to enhance the adsorption of MB on porous carbon. The results show that both HSBC-a and HSBC-a-b have ultra-high specific surface area (2979.59 m2/g for HSBC-a, 2882.73 m2/g for HSBC-a-b). The mesopore ratio of HSBC-a-b (Vmeso/Vtotal % = 14.05%) was doubled compared to HSBC-a. It showed an excellent adsorption performance of 694.03 mg/g for MB. It showed a fast adsorption kinetics and the adsorbed amount increased to 882.46 mg/g at 0.1 M NaCl solution. In addition, adsorption processes were studied using adsorption kinetics and adsorption isotherm model fitting. The results of this research confirm that hazelnut shell is a kind of promising and sustainable porous carbon raw material, and its ultra-high specific surface area and adjustable pore structure characteristics are favorable for the efficient treatment of MB from dyeing wastewater. This work could provide potential guidance for the high-value utilization of waste hazelnut shell biochar.

Sustainable Porous Carbons with Ultrahigh Specific Surface Areas for High-performance Supercapacitors

Waste biomass residues are prospective precursors for the preparation of sustainable porous carbons. In this work, we used the residues from Lonicera japonica Thunb and Ligusticum chuanxiong Hort to prepare porous carbons with ultra-high specific surface area (> 3000 m2 g−1), which deliver excellent capacitive performance for electrochemical double-layer capacitor. Porous carbon derived from Ligusticum chuanxiong Hort displays a specific capacitance of 314.4 F g−1 (1 A g−1) in three electrode system. The energy density of Ligusticum chuanxiong Hort-based symmetric supercapacitor reaches 8.4 Wh kg−1 at the power density of 519 W kg−1 in 6 M KOH. The cell remains a high energy density of 5.1 Wh kg−1 at an increased power density of 10.8 kW kg−1. Our work indicates that the waste biomass residues are promising and competitive precursors for the preparation of ultrahigh specific surface area porous carbons for supercapacitor application.

Nanoporous carbon doped with metal oxide microsphere as renewable flame retardant for integrating high flame retardancy and antibacterial properties of thermoplastic polymer composites

Innovative, renewable and cost-effective porous composites were developed for integrating high fire safety and antibacterial properties for thermoplastic polymers. Sustainable porous carbon sheets were developed from plum stones as fruits-by-products via single carbonization step affording dual environmental and economic benefits. The as-developed porous carbon own specific surface area of 165 m2 g−1 which is characteristic of mesoporous feature of an average mesopore size of 2.1 nm, in addition to naturally doped nitrogen species. The obtained porous carbons sheets were dispersed in different mass loadings in to polystyrene matrix-producing polymer composites. Interestingly, SnO2 microsphere of an average size of 2 µm was synthesized on the surface of developed porous carbon sheets producing new porous composites. The new composites were elucidated using XRD, FT-IR and SEM–EDS. Then, the developed composites were dispersed in polystyrene. The mass loadings were altered and studied. The progress in fire safety, thermal stability and antibacterial properties for developed polymer composites was studied. The flame retardancy of the new composites was significantly improved achieving rate of burning of 20.5 mm min−1 compared to 46.5 mm min−1 for blank polymer. This superior flame retardancy was corroborated by recording LOI value of 24.5% compared to 18% for virgin polymer. This attained flame retardancy was ascribed to the synergistic effect between porous carbon sheets contained nitrogen and SnO2 microsphere. The new composites afford promising inhibition for bacterial growth achieving clear antibacterial inhibition zone of 11 mm compared to zero for blank sample. The flame retardancy action was studied and elucidated.

Chitins from Seafood Waste as Sustainable Porous Carbon Precursors for the Development of Eco-Friendly Supercapacitors

Carbon materials derived from marine waste have been drawing attention for supercapacitor applications. In this work, chitins from squid and prawn marine wastes were used as carbon precursors for further application as electrodes for energy storage devices. Chitins were obtained through a deproteinization method based on enzymatic hydrolysis as an alternative to chemical hydrolysis as commonly presented in the literature. The obtained porous carbons were characterized using a BET surface area analyzer to determine the specific surface area and pore size, as well as scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), Raman spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), to characterize their morphology, composition, and structure. The electrochemical characterization was performed using a glassy carbon (GC) electrode modified with marine waste-based porous carbons as the working electrode through cyclic voltammetry and galvanostatic charge/discharge using ethaline, a choline chloride-based deep eutectic solvent (DES), as an eco-friendly and sustainable electrolyte. Squid and prawn chitin-based carbons presented a surface area of 149.3 m2 g-1 and 85.0 m2 g-1, pore volume of 0.053 cm3 g-1 and 0.029 cm3 g-1, and an associated specific capacitance of 20 and 15 F g-1 at 1 A g-1, respectively. Preliminary studies were performed to understand the effect of -OH groups on the chitin-based carbon surface with DES as an electrolyte, as well as the effect of aqueous electrolytes (1 mol L-1 sulphuric acid (H2SO4) and 1 mol L-1 potassium hydroxide (KOH)) on the capacitance and retention of the half-cell set up. It is provided, for the first time, the use of chitin-based carbon materials obtained through a one-step carbonization process combined with an eco-friendly DES electrolyte for potential application in energy storage devices.

Sustainable porous carbons from tannic acid based KOH activated as high-performance CO2 capture sorbents

A potentially viable strategy for the fabrication of efficient sorbents for CO2 capture is the use of porous carbons obtained from biomass, which have a large surface area and delicately organized porous structural framework.

Lotus-biowaste derived sulfur/nitrogen-codoped porous carbon as an eco-friendly electrocatalyst for clean energy harvesting

Recent research is focused on biomass-derived porous carbon materials for energy harvesting (hydrogen evolution reaction) because of their cost-effective synthesis, enriched with heteroatoms, lightweight, and stable properties. Here, the synthesis of porous carbon (PC) materials from lotus seedpod (LP) and lotus stem (LS) is reported by the pyrolysis method. The porous and graphitic structure of the prepared LP-PC and LS-PC materials were confirmed by field emission scanning electron microscopy, transmission electron microscopy with selected area electron diffraction, X-ray diffraction, and nitrogen adsorption-desorption measurements. Heteroatoms in LP-PC and LS-PC materials were investigated by attenuated total reflection-Fourier transform infrared and X-ray photoelectron spectroscopy. The specific surface area of LP-PC and LS-PC were calculated as 457 and 313 m2 g−1, respectively. Nitrogen and sulfur enriched LP-PC and LS-PC materials were found to be effective electrocatalysts for hydrogen evolution reactions. LP-PC catalyst showed a very low overpotential of 111 mV with the Tafel slope of 69 mV dec−1, and LS-PC catalyst achieved a Tafel slope of 85 mV dec−1 with a low overpotential of 135 mV. This work is expected to be extended for the development of biomass as a sustainable porous carbon electrocatalyst with a tunable structure, elements, and electronic properties. Furthermore, preparing carbon materials from the biowaste and applying clean energy harvesting might reduce environmental pollution.

Improved Microwave Absorption Performance with Sustainable Porous Carbon/Carbon Nanotube Composites

The great technological advancement in wireless communication systems and devices generated the problem of electromagnetic pollution. Developing lightweight, sustainable, and low-cost materials is necessary to minimize electromagnetic pollution. A sustainable porous carbon (PC) absorber material was obtained from the crude black liquor by a simple and low-cost synthesis, and combined with carbon nanotube (CNT), presenting excellent microwave attenuation results. The PC absorber at 20 wt.% filling ratio exhibited an intense reflection loss of ‑35.7 dB at 15.5 GHz, and bandwidth of 1.15 GHz for a thickness of 5.90 mm. By adding 0.2 wt.% of CNT, the reflection loss was -34.6 dB at 17.9 GHz, and a bandwidth of 1.54 GHz for 4.90 mm. The study reveals that the combination of PC and CNT improves the attenuation capacity, allows adjustment in the frequency range of the attenuation peak, and promotes thickness reduction. The results obtained allow us to advance studies in developing high-performance, sustainable, and low-cost microwave-absorbing materials.

Investigation of sustainable porous carbon as radar absorbing material

Radar Absorbing Materials (RAMs) are composite materials able to attenuate an incident electromagnetic wave. Usually, RAMs are made of a polymeric matrix and an electromagnetic absorbent filler, such as silicon carbide or carbon black. Several materials have been investigated as potential fillers, aiming to improve the Reflection Loss (RL) and absorption bandwidth broadening. In this paper, a composite made with silicone rubber and biochar was investigated as a sustainable porous carbon made with biomass waste. Five different composites were characterized, composed of 1 - 5 wt.% of biochar in the silicone rubber. Although the RL of pure biochar composites is not significant, it was demonstrated here how a biochar composite can improve the RL of a RAM material when it is applied as a double-layer structure. While the RL of a ferrite-based RAM with 2.0 mm thickness reaches -28 dB, a combination of this RAM with biochar composite reaches ~ -60 dB with the same thickness. The double-layer structure with 2.3 mm thickness can have an absorption bandwidth of 2.95 GHz over the X-band frequency range, and a structure with 2.6 mm thickness can reach a RL of ~ -76 dB. This demonstrates a sustainable, cheaper, and lighter material application (i.e., biochar), which is successfully used in the development of high-efficient electromagnetic shield or sensors.

Sustainable Porous Carbon with High Specific Surface Area from Soybean Shell via Hydrothermal Carbonization with H3PO4 for Electric Double‐Layer Capacitor Applications

Soybean shell (SS), as the byproduct of soybeans, is converted into porous carbon (PC) with a high specific surface area (SSA) via hydrothermal carbonization with H3PO4 followed by KOH activation. No obvious effect on the crystal structure of PC can be found by addition of H3PO4 during the hydrothermal process. However, the SSA of PC increases remarkably compared with hydrothermal carbonization without H3PO4, as H3PO4 assists in hydrothermal carbonization dehydration reactions and creates some pores beneficial for KOH activation. The SSA of the obtained PC reaches 2523 m2 g−1, and the hierarchical pore structure is mainly in 0.6–50 nm. The sample prepared by hydrothermal carbonization with 10 wt% H3PO4 and activation by KOH with the ratio of KOH/10‐hydrochar 3 under 700 °C exhibits a specific capacitance of 301 F g−1 in 6 m KOH electrolyte at the current density of 0.1 A g−1. It also has an excellent cycling stability with the specific capacitance remaining at 93.8% after 15 000 cycles. Furthermore, the energy density is 8.1 Wh kg−1 in the two‐electrode system. These results display that PC based on SS is a promising electrode material for the electric double‐layer capacitor.

Sustainable porous carbons from garlic peel biowaste and KOH activation with an excellent CO2 adsorption performance

Biomass is regarded as promising low-cost carbon source while the direct biomass pyrolysis usually shows low-surface-area or even non-porous, and therefore not useful for CO2 capture. Here, garlic peel was chemically activated by KOH to obtain carbons via the variation of temperature and KOH mass ratio, and the pore structure of carbons was evaluated by N2 adsorption. Importantly, carbon (gC-47) activated by four-fold KOH in mass at 700 °C exhibits well-developed porosity with surface area and pore volume of 1638 m2/g and 0.88 cm3/g, respectively. However, carbon (gC-27) activated by two-fold KOH in mass with lower surface area and pore volume but higher microporosity shows the highest CO2 uptake of 4.1 mmol/g at 25 °C and 1 bar. The results indicated that the critical factor for CO2 capture on carbon is microporosity not the traditionally believed surface area or pore volume, and an increase in porosity with special micropore size and moderate surface area will lead to the enhancement of CO2 uptake. This research provides significant guidance in designing adsorbents for CO2 capture, and the carbons from garlic peel can provide feasible option for CO2 capture with low-cost, environment friendship, and high capture capability.

Sustainable Porous Carbon Materials Derived from Wood-Based Biopolymers for CO₂ Capture.

Porous carbon materials with tunable porosities and functionalities represent an important class of CO2 sorbents. The development of porous carbons from various types of biomass is a sustainable, economic and environmentally friendly strategy. Wood is a biodegradable, renewable, sustainable, naturally abundant and carbon-rich raw material. Given these advantages, the use of wood-based resources for the synthesis of functional porous carbons has attracted great interests. In this mini-review, we present the recent developments regarding sustainable porous carbons derived from wood-based biopolymers (cellulose, hemicelluloses and lignin) and their application in CO2 capture.

Frequency Selective Surface Properties of Microwave New Absorbing Porous Carbon Materials Embedded in Epoxy Resin

In this manuscript, the electromagnetic wave absorption properties of sustainable porous carbon composites were evaluated over the X-band frequency range (8.2 - 12.4 GHz). The porous carbon material was made from the byproduct of cellulose production and was used as additive on the development of radar absorbing material (RAM) composites. These porous carbon materials have different characteristics, such as porosity size (180 µm < O1 < 250 µm and 425 µm < O2 < 500 µm) and particle size (ϕ1 < 250 µm and 250 µm < ϕ2 < 425 µm). Composite materials were also studied as frequency selective surface (FSS) structures. It was shown how complex permittivity and reflection loss (RL) can be manipulated over the frequency range using FSS structure. While regular RAM presented RL of 19 dB at ~11.8 GHz, FSS structure presented a RL of 19 dB shifted to 12.4 GHz regarding the same carbon porous material (with particles between 250 and 425 µm and porosity between 180 and 250 µm). It was demonstrated here the potential use of sustainable porous carbon as RAM, and how FSS structure can be used to tune the frequency of the RL maximum peak.

Winery wastes as precursors of sustainable porous carbons for environmental applications

Abstract An efficient alternative for the management and valorization of the huge amount of seasonal wastes generated by winery industries is shown. Sustainable porous carbons were successfully prepared by one-pot activation of grape bagasse, stalks and oil free-seeds. Benefiting from the high moisture of these residues, a prior hydrothermal carbonization increases the activation yield and generates carbons with less oxygen content and inorganic impurities. The mild physical or chemical activation of winery wastes resulted in highly microporous carbons with specific surface SBET up to 2053 m2/g and great potential for environmental protection and electrical energy storage. They are excellent sorbents for CO2 capture under post- and pre-combustion conditions (16 and 69 wt%, respectively) and achieve superior electrochemical capacitance of nearly 300 F/g in aqueous electrolyte and 180 F/g in ionic liquid based-medium.

Oxygen and Nitrogen Co‐enriched Sustainable Porous Carbon Hollow Microspheres from Sodium Lignosulfonate for Supercapacitors with High Volumetric Energy Densities

AbstractOxygen and nitrogen co‐enriched hierarchical porous carbon hollow microspheres are synthesized by using biomass‐derivative sodium lignosulfonate as a feedstock through a facile and scalable process. This four‐step synthesis process involves spray drying, thermal stabilization, carbonization, and post nitric acid modification. The as‐obtained carbon exhibits a moderate but efficient porosity (specific surface area of 991 m2 g−1, total pore volume of 0.75 cm3 g−1), small particle size of 0.2–5 μm, high electrode density of 0.45 g cm−3, and abundant surface oxygen/nitrogen species (13.12 at.%/0.97 at.%). Its electrochemical performance is evaluated by assembling into supercapacitors in 7 M KOH electrolyte. The three‐electrode cell presents a high gravimetric capacitance of 284 F g−1 at 0.1 A g−1 and good rate capability of 43.6 % at 20 A g−1. While the two‐electrode cell gives an impressive volumetric capacitance of 21.2 F cm−3 at 0.1 A g−1, marvelous volumetric energy density of 2.9 Wh L−1 at 11.3 W L−1, and remarkable cycling stability of 93.4 % capacitance retention after 10000 cycles, which is superior or comparable to that of commercial activated carbon.

Optimization of the Pore Structure of Biomass-Based Carbons in Relation to Their Use for CO2 Capture under Low- and High-Pressure Regimes.

A versatile chemical activation approach for the fabrication of sustainable porous carbons with a pore network tunable from micro- to hierarchical micro-/mesoporous is hereby presented. It is based on the use of a less corrosive and less toxic chemical, i.e., potassium oxalate, rather than the widely used KOH. The fabrication procedure is exemplified for glucose as precursor, although it can be extended to other biomass derivatives (saccharides) with similar results. When potassium oxalate alone is used as activating agent, highly microporous carbons are obtained (SBET ≈ 1300-1700 m2 g-1). When a melamine-mediated activation process is used, hierarchical micro-/mesoporous carbons with surface areas as large as 3500 m2 g-1 are obtained. The microporous carbons are excellent adsorbents for CO2 capture at low pressure and room temperature, able to adsorb 4.2-4.5 mmol CO2 g-1 at 1 bar and 1.1-1.4 mmol CO2 g-1 at 0.15 bar. However, the micro-/mesoporous carbons provide record-high room temperature CO2 uptakes at 30 bar of 32-33 mmol g-1 CO2 and 44-49 mmol g-1 CO2 at 50 bar. The findings demonstrate the key relevance of pore size in CO2 capture, with narrow micropores having the leading role at pressures <1 bar and supermicropores/small mesopores at high pressures. In this regard, the fabrication strategy presented here allows fine-tuning of the pore network to maximize both the overall CO2 uptake and the working capacity at any target pressure.

Polyurethane Foam-Based Ultramicroporous Carbons for CO2 Capture.

A series of sustainable porous carbon materials were prepared from waste polyurethane foam and investigated for capture of CO2. The effects of preparation conditions, such as precarbonization, KOH to carbon precursor weight ratio, and activation temperature, on the porous structure and CO2 adsorption properties were studied for the purpose of controlling pore sizes and nitrogen content and developing high-performance materials for capture of CO2. The sample prepared at optimum conditions shows CO2 adsorption capacities of 6.67 and 4.33 mmol·g(-1) at 0 and 25 °C under 1 bar, respectively, which are comparable to those of the best reported porous carbons prepared from waste materials. The HCl treatment experiment reveals that about 80% of CO2 adsorption capacity arises from physical adsorption, while the other 20% is due to the chemical adsorption originated from the interaction of basic N groups and CO2 molecules. The relationship between CO2 uptake and pore size at different temperatures indicates that the micropores with pore size smaller than 0.86 and 0.70 nm play a dominant role in the CO2 adsorption at 0 and 25 °C, respectively. It was found that the obtained carbon materials exhibited high recyclability and high selectivity to adsorption of CO2 from the CO2 and N2 mixture.

Sustainable porous carbons from lignocellulosic wastes obtained from the extraction of tannins

The present research study explores the possibility of obtaining high surface area activated carbons (ACs) from lignocellulosic wastes from the extraction of tannins. The use of vegetable tannins in the leather industry has the serious drawback that it involves the mass destruction of trees. Currently, studies are being conducted to obtain tannins from different lignocellulosic wastes. Two lignocellulosic wastes from the extraction of tannins, defatted grape seeds and acacia seed shells, with high carbon and nitrogen contents and a low ash content were obtained and investigated as a potential precursor for the preparation of activated carbons. KOH chemical activation, with a previous pyrolysis step, was performed in a conventional electric furnace varying the experimental conditions of KOH/precursor weight ratio, final activation temperature, and inert flow gas. After activation the samples were washed with a solution of HCl and water or just with hot water. The ACs obtained were essentially microporous with a specific surface area up to 2000m2g and presented low ash content, less than to 0.10% in the case of adsorbent materials from the defatted grape seeds and up to 3.60% for the materials from the acacia seed shells. The best results were obtained with the largest KOH/precursor weight ratio or the highest activation temperature (900°C). Their moderate nitrogen content (up to 1.5%) makes them especially suitable materials for CO2 capture. Some of them were more effective for CO2 adsorption than the commercial activated carbon F400 and therefore represent an attractive alternative to more expensive adsorbent materials.

Sustainable porous carbons with a superior performance for CO2 capture

Download options Please wait... Article information DOI https://doi.org/10.1039/C0EE00784F Article type Paper Submitted 17 Dec 2010 Accepted 17 Feb 2011 First published 18 Mar 2011 Download Citation Energy Environ. Sci., 2011,4, 1765-1771 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Sustainable porous carbons with a superior performance for CO2 capture M. Sevilla and A. B. Fuertes, Energy Environ. Sci., 2011, 4, 1765 DOI: 10.1039/C0EE00784F To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author Marta Sevilla Antonio B. Fuertes