Synthesis and applications of biomass-derived porous carbon materials in energy utilization and environmental remediation

Conversion of sustainable lignocellulosic biomass of sorghum stalks to ultra-high surface area nanostructured phosphorous doped carbons for efficient adsorption of cationic dyes

Biomass-based functional materials are known as versatile and cost-effective sources for the formation of different advanced nanocarbon materials. Sorghum stalks biomass is a main residual lignocellulosic agricultural material that produces in huge amounts after harvesting of sorghum grains. However, Sorghum stalks biomass material has low density, large specific volume, and no nutritional value, therefore actions are required for its valorization. This work investigates conversion of sorghum stalks into nanostructured carbon materials via thermochemical activation by phosphoric, which acts as activating and doping reagent at the same time. The formed carbon materials were characterized by ATR-FTIR, Raman spectroscopy, XRD, XPS, N2 adsorption/desorption, high-resolution TEM, EDX, and surface mapping. The formed carbon materials showed ultra-high surface area (up to 3010 m2/g), and extraordinary adsorption capacity towards methylene blue (MB) up to (456.6 mg/g). The adsorption isotherms were investigated with different adsorption isotherms and kinetic models. Accordingly, the best fit was obtained with the Langmuir adsorption isotherm, and pseudo-second-order kinetics. Thermodynamic investigations showed negative values for ΔH° and ΔG° at 298 K, which indicate physisorption and spontaneous adsorption process, respectively. The virtue of lignocellulosic structure of the sorghum stalks precursor in the formation of nanostructured carbon was addressed. An adsorption mechanism was suggested based on the adsorbate-adsorbent interaction which was detected by ATR-FTIR spectroscopy. The present findings demonstrate that efficient adsorbents were produced through an environmentally sustainable process involving valorization of residual sorghum stalks, which support and advance the current UN's sustainable development goals.

Converting New Zealand Slash into S-Doped Electrode Materials for High-Performance Supercapacitors

Slash is a waste product generated from commercial forestry operations. In 2022, flooding slash caused devastating damage when Cyclone Gabrielle directly impacted the Hawke's Bay region of New Zealand. This study addresses the dual challenges of waste management and sustainable materials development by converting forestry slash into high-performance carbon electrodes through an innovative in situ sulfur doping process. Building upon prior research involving waste-derived materials, this study develops a hydrothermal sulfurization technique that transforms New Zealand slash into sulfur-doped, highly graphitized carbon materials with excellent energy storage properties. The hydrothermally sulfurized slash-derived electrode material (C-HS-New Zealand Slash (NZS)) exhibits a high specific capacitance of 148 F g- 1 at a current density of 0.5 A g- 1. A supercapacitor device assembles with the C-HS-NZS electrode achieves a capacitance of 440 F g- 1 at the same current density. The energy density reaches 15.3 Wh kg- 1 at a power density of 250 W kg- 1. Furthermore, the C-HS-NZS-based device delivers a maximum capacitance of 384 F g- 1 and retains 360 F g- 1 after 10,000 cycles, demonstrating excellent capacity retention and long-term electrochemical stability.

Properties of Sunflower Straw Biochar Activated Using Potassium Hydroxide

Biochar is a kind of carbon material with a wide range of sources; it has attracted considerable attention because of its abundant resources and low cost. Potassium hydroxide (KOH) is a strong alkali activator that can effectively change the surface chemical properties and microstructure of biochar. Biochar activated by KOH has a large specific surface area (SSA) and a rich pore structure. Herein, sunflower straw was used as a raw material and KOH as an activator to investigate the preparation of sunflower straw biochar activated by KOH. The effects of synthetic conditions on the performance and structure of the resulting biochar materials were comprehensively analyzed. The final activation conditions were as follows: the impregnation ratio, activation time, and activation temperature were 2:1, 2 h, and 900 °C, respectively. The composition and structure of the prepared biochar were characterized. It was observed by SEM that the surface of the activated biochar became rougher. FTIR, XRD, XPS, and Raman characterization showed that the aromaticity and graphitization degree of the activated biochar increased. The activation process of biochar was analyzed via multiple techniques, aiming to lay the foundation for the wide application of biochar materials.

Hybridization-driven synchronous regeneration of biosensing interfaces for Listeria monocytogenes based on recognition of fullerol to single- and double-stranded DNA

A novel sensitive and reusable electrochemical biosensor for Listeria monocytegenes DNA has been constructed based on the recognition of water-soluble hydroxylated fullerene (fullerol) to single- and double-stranded DNA. First, the fullerol was electrodeposited on glassy carbon electrode (GCE), acting as a matrix for non-covalent adsorption of single-stranded probe DNA. Upon hybridization with the target DNA, the double helix structure was formed and desorbed from the electrode surface, driving synchronous regeneration of the biosensing interfaces. The biosensor showed a probe DNA loading density of 144 pmol∙cm-2 with the hybridization efficiency of 72.2%. The biosensor is applicable for the analysis of target DNA in actual milk samples with recoveries between 101.0% and 104.0%. This sensing platform provides a simple method for the construction of sensitive and reusable biosensor to monitor Listeria monocytogenes-related food pollution.

Pore Engineering in Biomass-Derived Carbon Materials for Enhanced Energy, Catalysis, and Environmental Applications

Biomass-derived carbon materials (BDCs) are highly regarded for their renewability, environmental friendliness, and broad potential for application. A significant advantage of these materials lies in the high degree of customization of their physical and chemical properties, especially in terms of pore structure. Pore engineering is a key strategy to enhance the performance of BDCs in critical areas, such as energy storage, catalysis, and environmental remediation. This review focuses on pore engineering, exploring the definition, classification, and adjustment techniques of pore structures, as well as how these factors affect the application performance of BDCs in energy, catalysis, and environmental remediation. Our aim is to provide a solid theoretical foundation and practical guidance for the pore engineering of BDCs to facilitate the rapid transition of these materials from the laboratory to industrial applications.

Agricultural biomass/waste-based materials could be a potential adsorption-type remediation contributor to environmental pollution induced by pesticides-A critical review

The widespread use of pesticides that are inevitable to keep the production of food grains brings serious environmental pollution problems. Turning agricultural biomass/wastes into materials addressing the issues of pesticide contaminants is a feasible strategy to realize the reuse of wastes. Several works summarized the current applications of agricultural biomass/waste materials in the remediation of environmental pollutants. However, few studies systematically take the pesticides as an unitary target pollutant. This critical review comprehensively described the remediation effects of crop-derived waste (cereal crops, cash crops) and animal-derived waste materials on pesticide pollution. Adsorption is considered a superior and highlighted effect between pesticides and materials. The review generalized the sources, preparation, characterization, condition optimization, removal efficiency and influencing factors analysis of agricultural biomass/waste materials. Our work mainly emphasized the promising results in lab experiments, which helps to clarify the current application status of these materials in the field of pesticide remediation. In the meantime, rigorous pros and cons of the materials guide to understand the research trends more comprehensively. Overall, we hope to achieve a large-scale use of agricultural biomass/wastes.

COF-derived porous nitrogen-doped carbon for removal of emerging organic contaminants and efficient uranium extraction from seawater

The development of adsorbents for efficient and highly selective seawater extraction of uranium was instrumental in fostering sustainable progress in energy and addressing the prevailing energy crisis. However, the complex background composition of the marine environment, including radionuclides, organic pollutants, and a large number of co-existing heavy metal ions, were non-negligible obstacles to the extraction of uranium from seawater. The present investigation successfully employed a self-templated approach to synthesize porous nitrogen-doped carbon (PNC) derived from COF, which exhibited tremendous potential as an adsorbent for pollutant removal in environmental treatment. LZU1@PNC not only retained the structural features of the original COF-LZU1, but also overcame the acid-base instability problem commonly found in COFs. Subsequently, the removal process of two typical water pollutants on the material was investigated using 2,4-DCP and [UO2(CO3)3]4-. The results demonstrated that LZU1@PNC exhibited superior removal performance for the target pollutants compared to COF-LZU1, owing to its larger specific surface area and abundant defect structure. After six desorption-regeneration cycles, LZU1@PNC still maintained a high removal rate of the target contaminants, demonstrating the stability of this material and its excellent recyclability. In addition, based on various characterization techniques, the removal mechanism of 2,4-DCP was presumed to be mainly electrostatic attraction, hydrogen bonding, and π-π stacking interactions. Conversely, the elimination process of [UO2(CO3)3]4- predominantly relied on surface complexation phenomena. The present investigation provided new perspectives and stimulated a broader study of other COF-derived carbon materials and their modifications as adsorbents for uranium extraction from seawater and other applications.

A Strategic Synthesis of Orange Waste-Derived Porous Carbon via a Freeze-Drying Method: Morphological Characterization and Cytocompatibility Evaluation

Porous carbon materials from food waste have gained growing interest worldwide for multiple applications due to their natural abundance and the sustainability of the raw materials and the cost-effective synthetic processing. Herein, orange waste-derived porous carbon (OWPC) was developed through a freeze-drying method to prevent the demolition of the original biomass structure and then was pyrolyzed to create a large number of micro, meso and macro pores. The novelty of this work lies in the fact of using the macro-channels of the orange waste in order to create a macroporous network via the freeze-drying method which remains after the pyrolysis steps and creates space for the development of different types of porous in the micro and meso scale in a controlled way. The results showed the successful preparation of a porous carbon material with a high specific surface area of 644 m2 g-1 without any physical or chemical activation. The material's cytocompatibility was also investigated against a fibroblast cell line (NIH/3T3 cells). OWPC triggered a mild intracellular reactive oxygen species production without initiating apoptosis or severely affecting cell proliferation and survival. The combination of their physicochemical characteristics and high cytocompatibility renders them promising materials for further use in biomedical and pharmaceutical applications.

Seafood waste derived carbon nanomaterials for removal and detection of food safety hazards

Nanobiotechnology and the engineering of nanomaterials are currently the main focus of many researches. Seafood waste carbon nanomaterials (SWCNs) are a renewable resource with large surface area, porous structure, high reactivity, and abundant active sites. They efficiently adsorb food contaminants through π-π conjugated, ion exchange, and electrostatic interaction. Furthermore, SWCNs prepared from seafood waste are rich in N and O functional groups. They have high quantum yield (QY) and excellent fluorescence properties, making them promising materials for the removal and detection of pollutants. It provides an opportunity by which solutions to the long-term challenges of the food industry in assessing food safety, maintaining food quality, detecting contaminants and pretreating samples can be found. In addition, carbon nanomaterials can be used as adsorbents to reduce environmental pollutants and prevent food safety problems from the source. In this paper, the types of SWCNs are reviewed; the synthesis, properties and applications of SWCNs are reviewed and the raw material selection, preparation methods, reaction conditions and formation mechanisms of biomass-based carbon materials are studied in depth. Finally, the advantages of seafood waste carbon and its composite materials in pollutant removal and detection were discussed, and existing problems were pointed out, which provided ideas for the future development and research directions of this interesting and versatile material. Based on the concept of waste pricing and a recycling economy, the aim of this paper is to outline current trends and the future potential to transform residues from the seafood waste sector into valuable biological (nano) materials, and to apply them to food safety.

Progress Made in Non-Metallic-Doped Materials for Electrocatalytic Reduction in Ammonia Production

The electrocatalytic production of ammonia has garnered considerable interest as a potentially sustainable technology for ammonia synthesis. Recently, non-metallic-doped materials have emerged as promising electrochemical catalysts for this purpose. This paper presents a comprehensive review of the latest research on non-metallic-doped materials for electrocatalytic ammonia production. Researchers have engineered a variety of materials, doped with non-metals such as nitrogen (N), boron (B), phosphorus (P), and sulfur (S), into different forms and structures to enhance their electrocatalytic activity and selectivity. A comparison among different non-metallic dopants reveals their distinct effects on the electrocatalytic performance for ammonia production. For instance, N-doping has shown enhanced activity owing to the introduction of nitrogen vacancies (NVs) and improved charge transfer kinetics. B-doping has demonstrated improved selectivity and stability, which is attributed to the formation of active sites and the suppression of competing reactions. P-doping has exhibited increased ammonia generation rates and Faradaic efficiencies, likely due to the modification of the electronic structure and surface properties. S-doping has shown potential for enhancing electrocatalytic performance, although further investigations are needed to elucidate the underlying mechanisms. These comparisons provide valuable insights for researchers to conduct in-depth studies focusing on specific non-metallic dopants, exploring their unique properties, and optimizing their performance for electrocatalytic ammonia production. However, we consider it a priority to provide insight into the recent progress made in non-metal-doped materials and their potential for enabling long-term and efficient electrochemical ammonia production. Additionally, this paper discusses the synthetic procedures used to produce non-metal-doped materials and highlights the advantages and disadvantages of each method. It also provides an in-depth analysis of the electrochemical performance of these materials, including their Faradaic efficiencies, ammonia yield rate, and selectivity. It examines the challenges and prospects of developing non-metallic-doped materials for electrocatalytic ammonia production and suggests future research directions.

The potential of lignocellulosic biomass for magnetic solid phase extraction of naproxen from saliva samples

This paper presents a study on the application of magnetic biochars derived from three distinct biomass sources: almond (AMBC), walnut (WMBC), and peanut (PMBC) shells for magnetic solid-phase extraction (MSPE) of naproxen, a non-steroidal anti-inflammatory drug, from human saliva prior to LC-MS analysis. The three magnetic biochars were synthesized and characterized through IR, XRD, SEM, and EDX analyses. This work explored the factors influencing extraction efficiency using these three bioadsorbents through experimental design. The results obtained revealed that magnetic biochar derived from almond shells demonstrated outstanding performance in terms of naproxen extraction, achieving an impressive yield of 100.2%. This remarkable efficiency was achieved by optimizing parameters, including a 12-minute extraction time, a 3.5 mL elution volume, a 10 mg adsorbent mass, and a 4-minute elution time. Consequently, this study established almond shell as a low-cost, environmentally friendly, and efficient magnetic biochar for extracting naproxen from human saliva. This superior performance was made possible due to the abundant lignocellulosic potential inherent in almond shell structures, surpassing that of the other two biochars. The combination of magnetic extraction with LC-MS demonstrates good linearity, with an R2 value equal to 0.9987. The limits of detection (LOD) and quantification (LOQ) are 0.013 and 0.047 μg L-1, respectively.