Carbon Precursor Research Articles

Synthesis of Wafer-Scale SWCNT Forests with Remarkably Invariant Structural Properties in a Bulk-Diffusion-Controlled Kinetic Regime

Robust synthesis of vertically aligned carbon nanotubes (VACNT) at large scale is required to accelerate deployment of numerous cutting-edge devices to emerging commercial applications.1 Large-area single-walled (SW) CNT forests with high densities and small diameters are especially important for many applications, yet they are conspicuously absent from the literature due to reproducibility and synthesis challenges, which are further exacerbated when flexible metal foils are used as support instead of traditional Si or quartz wafers. To address this need, we demonstrate that the structural characteristics of SWCNTs produced in a growth regime dominated by bulk diffusion of the gaseous carbon precursor are remarkably invariant over a broad range of process conditions (precursor concentration increased up to 30-fold, catalyst substrate area from 1 cm2 to 180 cm2, growth pressure from 20 to 790 mbar, and gas flowrates up to 8-fold).2 Forests structural properties are also preserved when growth is transitioned from Si wafers to Inconel metal foils.3 We show that a simple growth kinetics model that accounts for both reactant bulk diffusion and competing byproduct formation in the presence of excess hydrogen quantitatively reproduces the experimental data in the entire isothermal parameter space. The model enables critical predictions for process scale-up optimization including a potential 6-fold increase in CNT production rate, a ~ 90% carbon conversion efficiency in select conditions, and elimination of reaction rate decay observed at high pressures by using a hydrogen-free growth environment. This model-guided opportunity to substantially improve synthesis throughput and efficiency, in conjunction with the remarkably invariant CNT properties on both metal and insulating substrates, is appealing for reliable VACNT device fabrication at both small and industrial scales.This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. References Rao, R.; Pint, C. L.; Islam, A. E.; Weatherup, R. S.; Hofmann, S.; Meshot, E. R.; Wu, F.; Zhou, C.; Dee, N.; Amama, P. B.; Carpena-Nuñez, J.; Shi, W.; Plata, D. L.; Penev, E. S.; Yakobson, B. I.; Balbuena, P. B.; Bichara, C.; Futaba, D. N.; Noda, S.; Shin, H.; Kim, K. S.; Simard, B.; Mirri, F.; Pasquali, M.; Fornasiero, F.; Kauppinen, E. I.; Arnold, M.; Cola, B. A.; Nikolaev, P.; Arepalli, S.; Cheng, H.-M.; Zakharov, D. N.; Stach, E. A.; Zhang, J.; Wei, F.; Terrones, M.; Geohegan, D. B.; Maruyama, B.; Maruyama, S.; Li, Y.; Adams, W. W.; Hart, A. J. Carbon Nanotubes and Related Nanomaterials: Critical Advances and Challenges for Synthesis toward Mainstream Commercial Applications. ACS Nano 2018, 12, 11756-11784.Park, S. J.; Moyer-Vanderburgh, K.; Buchsbaum, S. F.; Meshot, E. R.; Jue, M. L.; Wu, K. J.; Fornasiero, F. Synthesis of wafer-scale SWCNT forests with remarkably invariant structural properties in a bulk-diffusion-controlled kinetic regime. Carbon 2023, 201, 745-755.Moyer-Vanderburgh, K.; Ma, M. C.; Park, S. J.; Jue, M. L.; Buchsbaum, S. F.; Wu, K. J.; Wood, M.; Ye, J.; Fornasiero, F. Growth and Performance of High-Quality SWCNT Forests on Inconel Foils as Lithium-Ion Battery Anodes. ACS Appl Mater Interfaces 2022, 14, 54981-54991.

Coal-derived flaky hard carbon with fast Na+ transport kinetic as advanced anode material for sodium-ion batteries

Hard carbon (HC) has demonstrated a significant potential in anode for sodium-ion batteries (SIBs) due to its superior electrochemical properties. Coal is considered a promising hard carbon precursor due to its high carbon yield. However, the widespread adoption of coal-derived HC faces challenges such as limited storage capacity and decreased rate performance, primarily attributed to the dense structure of coal. In this study, a molten salt-assisted approach was developed to adjust the microstructure of coal-derived HC. The dense coal is etched into a flaky structure by molten salt, which is conducive to the diffusion and transport of sodium ions. The optimized HC materials possess large interlayer spacing and abundant pseudo-graphitic domains, exhibiting a remarkable reversible capacity of 303.6 mA h g−1 at 30 mA g−1 and 82.1 mA h g−1 at 500 mA g−1. Besides, a full cell with the configuration of as-prepared coal derived HC versus Na3V2(PO4)2O2F (NVPOF) is presented with a high initial coulombic efficiency of 76.15 % and capacity of 100.7 mA h g−1. The results indicate that our synthesis strategy is feasible for the application of coal derived carbon materials in SIBs.

Chitin-Derived Hierarchical Meso- and Microporous Carbon Enables High-Rate Sulfur Cathode of Sodium-Sulfur Batteries.

Room temperature Na-S batteries are considered as a promising alternative energy storage system because of their abundant material resources and high theoretical energy density. However, the severe polysulfide shuttle effect and slow reaction kinetics hinder their practical application. Herein, a hierarchical meso- and microporous carbon with nitrogen self-doping (NSPC) is prepared using chitin as the carbon precursor and serves as a novel host to confine the sulfur (S⊂NSPC). An optimized structure of NSPC, including abundant graphite nanocrystals, large pore volume of 1.76 cm3 g-1, and large specific surface area of 2073 m2 g-1 is obtained at the carbonization temperature of 1000 °C. These merits contribute to significantly enhanced charge transfer and ion diffusion of the as-prepared S⊂NSPC-1000 cathode, which exhibits the outstanding sodium storage performance, including high reversible capacities of 1207 mAh g-1 at 0.1 C and 891 mAh g-1 at 2 C and stable cycling with a low capacity decay for 400 cycles at 1 C, among other S⊂NSPC cathodes and previously reported cathodes for Na-S batteries. This cathode can also afford stable cycling at a high sulfur loading.

Low-Cost and Eco-Friendly Calcium Oxide Prepared via Thermal Decompositions of Calcium Carbonate and Calcium Acetate Precursors Derived from Waste Oyster Shells.

Waste oyster shells were utilized to produce calcium carbonate (CaCO3) by grinding. This CaCO3 was then reacted with acetic acid to yield calcium acetate monohydrate (Ca(CH3COO)2·H2O). Both CaCO3 and Ca(CH3COO)2·H2O were used as precursors for synthesizing calcium oxide (CaO) through thermal decomposition at 900 °C and 750 °C, respectively. The yields of CaO from both precursors, determined through calcination experiments and thermogravimetric analysis (TGA), exceeded 100% due to the high purity of the raw agents and the formation of calcium hydroxide (Ca(OH)2). X-ray fluorescence (XRF) analysis revealed a CaO content of 87.8% for CaO-CC and 91.5% for CaO-CA, indicating the purity and contamination levels. X-ray diffraction (XRD) patterns confirmed the presence of CaO and minor peaks of Ca(OH)2, attributed to moisture adsorption. Fourier-transform infrared (FTIR) spectroscopy identified the vibrational characteristics of the Ca-O bond. Scanning electron microscopy (SEM) showed similar morphologies for both CaO-CC and CaO-CA, with CaO-CA displaying a significant amount of rod-like crystals. Based on these results, calcium acetate monohydrate (CA) is recommended as the superior precursor for synthesizing high-purity CaO, offering advantages for various applications.

New Approach for Plasma Nitrocarburizing of Stainless Steels by a Modified Reactor Configuration Using a Plasma‐Activated Solid Carbon Precursor

Stainless steel surfaces can be modified using plasma‐assisted thermochemical treatments to improve properties like hardness, wear, and pitting corrosion resistance. To specifically adjust the desired properties, a precise control of the produced treatment‐relevant gas species with regard to their type and concentration is essential. This requires the adjustment of the parameters for the generation of the gas species, being independent from heating parameters, as well as their real‐time measurement. Therefore, this study presents the use of a plasma‐activated solid carbon precursor in a cold‐wall reactor using active screen technology and in a modified hot‐wall reactor during plasma nitrocarburizing of austenitic stainless steel. In addition, the modified hot‐wall reactor combined with a compact laser‐based absorption spectroscopy sensor for real‐time monitoring and concentration evaluation of in‐site generated gas species. It is shown that implementing a plasma‐activated solid carbon precursor in a modified hot‐wall reactor enables adjustable generation of C‐containing gas species, particularly HCN, with high production yield by an independent power management. Therefore, HCN is produced independent from heating while the limitations arising during active screen technology using a carbon screen are avoided. The presented technological development thus opens up new possibilities for better control of the plasma nitrocarburizing treatments of steels.

Phenolic resin-based nanoflower porous carbon synthesized by self-assembly of MgO hydrolysis for boosting supercapacitor performance

Although electrode materials with flower-like structures have showing promising achievement for battery energy storage for stable structure and rich specific surface area, there are still some challenges in precisely controlling their microstructure. Inspired by the hydrolysis and self-assembly of MgO into petal-like magnesium hydroxide crystals under alkaline critical micelle conditions, we have proposed to synthesize a unique phenolic resin with a 3D flower-like structure as a carbon precursor. After a series of treatments, the optimal sample consists of nanosheets (thickness ≈27 nm) extending in all directions from the core, with a porous structure, significant specific surface area of 2028 m2/g and pore volume of 1.79 m3/g. Electrochemical experiments confirmed that the sample exhibits satisfactory electrochemical performance as the electrode of supercapacitor. It shows an amazing unique capacitance of 320.1 F/g, and the charge–discharge capacity retention rate exceeds 94.6 % after 5000 cycles. Moreover, a high energy density of 9.44 Wh/kg at 126 W/kg is shown for the symmetrical supercapacitors. We believe that the 3D flower-like morphology formed by the unique lamellar structure can provide more active sites, promote ion transports and increase the stability of structure. These findings suggest a new strategy to control the morphology of phenolic resin-based carbon materials.

Sucrose‐Based Dense, Pure, and Highly‐Crystalline Graphitic Materials for Lithium‐Ion Batteries

AbstractAt present, most synthetic graphite materials commonly used as anode active ingredients in lithium‐ion cells are produced by graphitization of petroleum cokes. The carbon footprint associated with synthetic graphite production is significant. Thus, bio‐derived and cheap precursors, such as saccharides, would be an attractive alternative for the sustainable production of graphitic carbons. However, they are non‐graphitizing at temperatures as high as 3000 °C, preserving the curved, fullerene‐like structure of graphene layers and microporosity. Consequently, many lithium ions are consumed during the formation of solid electrolyte interphase films and passivated in the nanovoids. Here, a method for the production of pure, crystalline, graphitic materials based on sucrose disposed of microporosity is presented, which also works with a variety of saccharides and other organic precursors of hard carbons—generally considered incapable of such transformation. This process employs catalytic graphitization by Si particles at high temperatures. The electrochemical response of such derived sucrose‐based graphite in Li‐ion half‐cells demonstrated its feasibility to serve as an anode active material for rechargeable Li‐ion batteries.

Self-supported bimetallic iron-nickel sulfide nanosheets for efficient alkaline electrocatalytic oxygen evolution

The ongoing pursuit of cost-effective approaches for synthesizing transition metal sulfide heterostructure oxygen evolution electrocatalysts, with the objective of optimizing active site exposure and stabilizing spatial framework, remains a significant challenge. In this study, self-supported bimetallic iron-nickel sulfide (Fe1-xS-NiS/NF) nanosheet heterostructures were successfully fabricated in situ on nickel foam through the direct sulfurization of bimetallic carbonate precursors. The effects of sulfurization temperature and Fe content on the oxygen evolution reaction (OER) performance of the catalyst are investigated, and the best conditions are found to be 350 °C and 2 mmol, respectively. As expected, the optimized catalyst demonstrates remarkable OER performance in an alkaline solution with low overpotentials of 235 mV and 333 mV at high current densities of 50 mA cm−2 and 100 mA cm−2, respectively. Furthermore, the catalyst shows long-term stability lasting for 35 h at 60 mA cm−2 with a negligible shift in the polarization curve observed even after 2000 cyclic voltammetry cycles, while also exhibiting good structural preservation. The current study has the potential to offer valuable insights into the fabrication of electrocatalysts based on metal sulfide heterostructures.

Highly Efficient Laser Bidirectional Graphene Printing: Integration of Synthesis, Transfer and Patterning.

Graphene has tremendous potential in future electronics due to its superior force, electrical, and thermal properties. However, the development of graphene devices is limited by its complex, high-cost, and low-efficiency preparation process. This study proposes a novel laser bidirectional graphene printing (LBGP) process for the large-scale preparation of patterned graphene films. In LBGP, a sandwich sample composed of a thermoplastic elastomer (TPE) substrate, carbon precursor powder, and a glass cover is irradiated by a nanosecond pulsed laser. The laser photothermal effect converts the carbon precursor into graphene, with partial graphene sheets deposited directly on the TPE substrate and the remaining transferred to the glass cover via a laser-induced plasma plume. This method simultaneously prepares two face-to-face graphene films in a single laser irradiation, integrating synthesis, transfer, and patterning. The resulting graphene patterns demonstrate good performance in flexible pressure sensing and Joule heating, showcasing high sensitivity (7.7kPa-1), fast response (37ms), and good cycling stability (2000 cycles) for sensors, and high heating rate (1°Cs-1) and long-term stability (3000s) for heaters. It is believed that the simple, low-cost, and efficient LBGP process can promote the development of graphene electronics and laser manufacturing processes.

Effect of carbonization methods on graphitization of soft and hard carbons

Pressurized carbonization is known to improve carbon content and create textural changes in resultant carbon compared to conventional (atmospheric) carbonization. However, further studies investigating the impact of these carbonization methods on the graphitic quality of the carbon precursors have not been explored extensively. This study investigates the influence of carbonization methods on the graphitization behavior of soft and hard carbons using a three-model system: phenolic resole (hard carbon), polyvinyl chloride (PVC) (soft carbon), and a 50:50 blend of resole and PVC. Carbonization was conducted under autogenic pressure (AGP) and atmospheric pressure (APP) at 500 °C for 5 h, followed by high-temperature treatment at varying temperatures. Various techniques, including X-ray diffraction and Raman spectroscopy showed hard carbon precursors exhibited improved properties under AGP carbonization such as larger crystallite size, sharp crystalline peaks, lower ID/IG ratio, and narrow G-full width half-maximum, an indication of improved crystallinity by lowering amorphous phase at high temperature. For soft carbon precursors, the method of carbonization did not impact the graphitization level. The most significant finding was the enhanced crystalline nature observed in hard carbon under AGP conditions, without the need for any catalyst. It shows the influence of pressure on improving the crystallinity of hard carbon precursors.

One-Pot Synthesis of C@BiOBr for Efficient Photocatalytic Degradation of Phenol.

This work describes the synthesis of C@BiOBr using glucose as the carbon precursor by a repeatable one-step hydrothermal method. Characterization studies indicate that the structure of BiOBr did not change after the carbon layer was encapsulated on the surface. The highest activity is achieved at 1.2-C@BiOBr, with 97% of phenol (50 mg·L-1) degrading within 90 min, and the degradation amount of phenol is determined to be 48.5 mg·g-1 with a speed of 0.54 mg·g-1·min-1. The useful species of phenol degradation are studied and assigned to •O2-, 1O2, and h+. The effect of coated carbon layer for photocatalytic degradation of phenol over BiOBr is studied by photoelectrochemical experiments, fluorescence spectra, and density functional theory (DFT) calculations. It is attributed to the good conductivity of carbon, enhanced separation of the photocarriers by carbon coating, and thermodynamically favorable reactive oxygen species (ROS) production on the surface of carbon. This work demonstrates that carbon coating is an effective strategy to improve the photocatalytic activity of BiOBr and reveals the detailed mechanism.

Examining the varied localization of oxygen groups on graphene nanosheets and their entangled influence on electromagnetic waves’ absorption within polymeric coatings

In this study, two distinct graphene nanosheets, featuring varying localization of oxygen groups, were synthesized to investigate their influence on the electromagnetic waves’ absorption properties of polymeric coatings. Natural graphite flakes and expanded graphite served as carbon precursors for synthesizing Edge-Functionalized Graphene Oxide (E-GO) and Basal-Functionalized Graphene Oxide (B-GO) nanosheets, respectively. Subsequently, polymer nanocomposite coatings were fabricated by dispersing E-GO and B-GO into a waterborne epoxy matrix. The dielectric properties of these coatings were measured post-in-situ thermal reduction at 225 °C. Results revealed that coatings containing B-GO nanosheets exhibited higher dielectric values compared to those with E-GO nanosheets. Furthermore, the electromagnetic properties of the coatings were examined to correlate the network formation findings obtained from dielectric studies and reflection loss values. It was demonstrated that an improved dispersion state of graphene nanosheets resulted in enhanced interphase formation between epoxy and graphene nanosheets, thereby improving interfacial polarization and dielectric permittivity values. Additionally, residual oxygen groups situated on the graphene basal plane induced dipolar polarization, consequently enhancing the reflection loss values of electromagnetic waves. Ultimately, the enhancements in electrical conductivity and dielectric permittivity contributed to reflection loss values reaching −52.67 dB in coatings with a thickness of 320 μm and a graphene loading level of 1.5 wt%, representing significant advancements compared to existing literature.

Tuning electronic structure of metal-free dual-site catalyst enables exclusive singlet oxygen production and in-situ utilization

Developing eco-friendly catalysts for effective water purification with minimal oxidant use is imperative. Herein, we present a metal-free and nitrogen/fluorine dual-site catalyst, enhancing the selectivity and utilization of singlet oxygen (1O2) for water decontamination. Advanced theoretical simulations reveal that synergistic fluorine-nitrogen interactions modulate electron distribution and polarization, creating asymmetric surface electron configurations and electron-deficient nitrogen vacancies. These properties trigger the selective generation of 1O2 from peroxymonosulfate (PMS) and improve the utilization of neighboring reactive oxygen species, facilitated by contaminant enrichment at the fluorine-carbon Lewis-acid adsorption sites. Utilizing these insights, we synthesize the catalyst through montmorillonite (MMT)-assisted pyrolysis (NFC/M). This method leverages the role of MMT as an in-situ layer-stacked template, enabling controlled decomposition of carbon, nitrogen, and fluorine precursors and resulting in a catalyst with enhanced structural adaptability, reactive site accessibility, and mass-transfer capacity. The NFC/M demonstrates an impressive 290.5-fold increase in phenol degradation efficiency than the single-site analogs, outperforming most of metal-based catalysts. This work not only underscores the potential of precise electronic and structural manipulations in catalyst design but also advances the development of efficient and sustainable solutions for water purification.

Exploring the Ultralong Lifetime of Self‐matrix 1,10 Phenanthroline and Boron‐Based Room Temperature Phosphorescence Carbon Dots for Multiple Applications

AbstractRoom temperature phosphorescence carbon dots (RTP CDs) are one of the newly investigated nanomaterials because of their remarkable optical characteristics. They are widely utilized in many versatile optoelectronic and security applications. Apart from synthesis, one of its challenging attributes is its lifetime at room temperature. Here, a straightforward and quick heating approach is presented for synthesizing self‐matrix 1,10 phenanthroline and boron‐based RTP CDs. 1,10 phenanthroline is utilized as an aromatic and hetero atom containing carbon precursor and boric acid is used as a passivating to stabilize the triplet excitons and prevent nonradiative deactivation. Various characterization techniques like TEM, XRD, FTIR, UV–vis, PL, and elemental analysis (ICP and CHNS) have been used to study the properties of self‐matrix RTP CDs. The RTP CDs exhibited excellent blue‐green emission when excited at 302 nm. Compared to the available literature, the novelty of this work is observed from its high naked eye phosphorescence characteristic of ≈22 s with an average lifetime of ≈ 2.4 s at 302 nm, making them ultralong self‐matrix RTP CD material. Due to their exceptional qualities, the self‐matrix RTP CDs have been widely employed for various applications, including information encryption decryption, phosphor for LEDs, anticounterfeiting, and water sensitivity analysis.

A single-component sensor array to detect multiple antibiotics via dual-emission chlorophyll carbon dots

In this study, dual-emission carbon dots (DE-CDs) were fabricated using a straightforward one-step hydrothermal synthesis with natural chlorophyll as the carbon precursor. These DE-CDs not only preserve the porphyrin structure of chlorophyll, exhibiting notable fluorescence at 682 nm, but they also display the characteristic fluorescence emission of conventional CDs at 450 nm. Leveraging the unique dual-emission properties of DE-CDs, we have engineered a single-component fluorescent sensor array for the high-throughput detection of antibiotics, which are emerging contaminants in water. The fluorescence responses (F450, F682, and the F450/F682 ratio) of the DE-CDs toward various antibiotics were analyzed using principal component analysis (PCA), enabling the facile differentiation of multiple antibiotics with good reproducibility achieved in real water samples. This innovative DE-CDs approach eliminates the need for multiple sensing probes and offers a practical concept for the creation of single-component sensing platforms.

Synthesis of titanium carbide (TiC) using recycled precursor for potential scale-up of low-cost MXene

In this study, we report the low-cost synthesis of titanium carbide (TiC) from recycled precursors and further used to synthesize MAX phase material, Ti3AlC2. The recycled precursor, carbon extracted from the used tyres using a few processes is used to synthesize TiC with high purity. The use of tyre-derived carbon offers several environmental benefits such as facile synthesis, low cost, environment-friendly, etc. The as-synthesized TiC is further used as a precursor to synthesize low-cost Ti3AlC2. The structure of TiC and Ti3AlC2 are characterized by UV–visible spectroscopy and X-ray diffraction analysis. The microstructure and surface morphology of the samples are examined using scanning electron microscope imaging and energy-dispersive X-ray spectroscopy. The chemical bonding information is analyzed by Fourier transform infrared spectroscopy and the thermal behaviour of the samples are examined using thermogravimetric analysis. The successful cost-effective synthesis of TiC and Ti3AlC2 are confirmed from XRD analysis and the samples show high purity. TiC and Ti3AlC2 show excellent thermal stability which helps in their potential applications in the future. This study proclaims a new strategy to synthesize low-cost Ti3AlC2 MXene for the large-scale production using TiC precursor where the TiC precursor is synthesized using carbon precursor.

Effect of methane flow in inverse diffusion flame and surface morphology on synthesis of copper–carbon nanotubes composite

ABSTRACT In an inverse diffusion flame of fuel-rich methane–air mixture, a distinct separation between a yellow flame situated atop a high-temperature blue flame structure enabled the growth of carbon nanotubes on relatively low melting temperature copper substrates within a carbon-rich precursor environment. However, high-affinity passivation layers formation on copper prevented the diffusion of carbon precursors, rendering the growth of carbon nanotubes on copper challenging. Removal of passivation layers via sulphuric acid treatment facilitates the synthesis of carbon nanotubes within the flame. Nevertheless, the impact of sulphuric acid treatment on the surface morphology of copper, and its influence on the growth of carbon nanotubes in the presence of methane–air mixtures, remains relatively unexplored. This research investigates the effects of sulphuric acid treatment and methane–air mixtures towards the growth of carbon nanotubes on copper substrates. Application of sulphuric acid treatment yields a surface characterised by high surface area-to-volume nano-hills morphology, which enhances the adsorption of carbon atoms and leads to the growth of carbon nanotubes with lifted copper nanoparticles. The optimal growth of carbon nanotubes occurs at a specific methane flow rate, where the supply of carbon precursors aligns with the diffusion of carbon atoms and growth rate of carbon nanotubes.

Enhancing the valorization of pulping black liquors in production effective aerogel–carbon nanostructure as adsorbents toward cationic and ionic dyes

This work deals with promoting the efficiency of removing the cationic and ionic dyes by new aerogel–carbon nanostructures. For cleaner production the rice straw-pulping black liquors, which regards serious environmental risk during routine disposing, is used in preparing the aerogel precursors. These aerogels (AGBs) depend on using pulping black liquor in hybrid with resorcinol and the less carcinogenic formaldehyde butyraldehyde. Black liquors from five pulping processes are used, Elemental, thermogravimetric (TGA and DTG), and FTIR-ATR analyses are used to characterize the carbon precursors. While their adsorption behavior toward cationic and anionic dyes are accessed via iodine-value, adsorption capacity and kinetic models, textural characterization, and SEM. The TGA measurements reveal that AGBs from BLs of neutral sulfite and soda-borohydride pulping reagents have higher activation and degradation energies than other aerogels. In terms of cationic and anionic dyes adsorption as well as textural characterization, the AGB-CNSs surpass that made from BLs. The discarded KOH/NH4OH black liquor is used to synthesize the best aerogel precursor for producing cationic methylene blue dye (MB) adsorbent, where it provides an adsorption capacity 242.1 mg/g. The maximum anionic brilliant blue dye (BB) adsorption capacity, 162.6 mg/g, is noticed by Kraft BL-aerogel-CNSs. These finding data overcome the literature carbon adsorbents based on lignin precursors. All examined CNSs toward MB dye follow the Langmuir adsorption equilibrium; while primarily the Freundlich model for BB dye. The pseudo-second-order kinetic model well fits the adsorption kinetics of investigated AGB-CNSs. The textural characterization and SEM revealed a mixture of mesoporous and micro porous features in the CNSs.

Eco-friendly synthesis and application of NH2-COOH functionalized Fe3O4@graphite carbon microballs in heavy metal removal

Heavy metal pollution in wastewater is quite challenging for the environment. This study pioneers the synthesis of a novel adsorbent, amine-acid functionalized Fe3O4 decorated carbon micro-balls (NH2-COOH/Fe3O4@CMBs) via hydrothermal process and controlled thermal treatment under nitrogen atmosphere, utilizing eco-friendly resource glucose as a carbon precursor. The formation of cubic Fe3O4 nanoparticles and crystalline graphite within a carbon core-shell structure is confirmed. NH2-COOH/Fe3O4@CMBs show a porosity conducive to ion exchange in the range of 100–300 nm via FE-SEM, exhibiting a significant surface area of 494 m²/g with optimal pore volume. Within the carbon matrix, H2-TPR affirms the robust integration of Fe3O4, essential for high adsorption rates. In practical applications, NH2-COOH/Fe3O4@CMBs demonstrate exceptional performance, removing ∼ 99 % of Pb2+ ions in 30 min., showcasing an impressive adsorption capacity of 360 mg/g. The rapid and potent adsorption is attributed to the electron-rich graphite layers and the presence of abundant chelating sites. This research introduces NH2-COOH/Fe3O4@CMBs as a commercially viable and environmentally responsible solution for the removal of hazardous heavy metals from wastewater. Scientific understanding of adsorptive material not only advances but also offers a tangible approach to mitigate a pressing public health concern, marking a significant stride towards sustainable water treatment technologies.

Removal of tetracycline from the aquatic environment using activated carbon: A comparative study of adsorption performance based on the activator agents

This research focus endeavour to compare the remediation of tetracycline (TC) through activated carbon (AC), crafted utilizing two distinct chemical activators: zinc chloride (ACZ), and potassium hydroxide (ACK), using pine cone biowaste as an effective carbon precursor, followed by microwave-assisted activation. The impact of TC removal by ACZ and ACK adsorbents was thoroughly examined. The influence of pH, adsorbent mass, adsorption isotherms, kinetics, and inclusive thermodynamics were studied. Our results revealed that the interaction between TC and ACZ or ACK adsorbents aligned well with the model of pseudo-second-order kinetics, whilst the Langmuir model fitted the adsorption isotherm data of ACZ and ACK. The ACZ have a maximum adsorption capacity of 327.87 mg/g compared to that of the ACK (283.29 mg/g). Adsorption of TC was facilitated by the suitable pore volume, abundant microporous, and mesoporous structure of these adsorbents. The ACZ adsorbent is abundant in oxygen-containing functional groups, compared to ACK with minimized reactive sites, in bonding with the TC molecules through hydrogen bonding, for faster removal of TC. Our finding from this work further highlights that the synthesized ACZ from pine cones evidenced significant environmental potentials in the elimination of antibiotics from aqueous solution, to promote clean application perspectives.