Search Results (218)

Conventional methods for the synthesis of porous carbons are typically time- and energy-consuming and often contribute to the excessive accumulation of waste solvents. An alternative approach is to employ environmentally friendly procedures, such as mechanochemical synthesis, which holds great potential for large-scale production of advanced carbon-based materials in coming years. This review covers mechanochemical syntheses of highly porous carbons, with a particular focus on new adsorbents and catalysts that can be obtained from biomass. Mechanochemically assisted methods are well suited for producing highly porous carbons (e.g., ordered mesoporous carbons, hierarchical porous carbons, porous carbon fibers, and carbon–metal composites) from tannins, lignin, cellulose, coconut shells, nutshells, bamboo waste, dried flowers, and many other low-cost biomass wastes. Most mechanochemically prepared porous carbons are proposed for applications related to adsorption, catalysis, and energy storage. This review aims to offer researchers insights into the potential utilization of biowastes, facilitating the development of cost-effective strategies for the production of porous carbons that meet industrial demands. Full article

Prostate cancer is a serious, life-threatening condition among men, usually requiring long-term chemotherapy. Due to its high efficacy, bicalutamide, a non-steroidal anti-androgen, has widespread use. However, its poor water solubility, low oral bioavailability, and nonspecific systemic exposure limit its application. To overcome these obstacles, our study explored the potential of non-carboxylated and carboxylated mesoporous carbon nanoparticles (MCN) as advanced drug carriers for bicalutamide (MCN/B and MCN-COOH/B). The physicochemical properties and release behaviour were thoroughly characterized. Functionalization with carboxylic groups significantly improved wettability, dispersion stability, as well as loading efficiency due to enhanced hydrogen bonding and π–π stacking interactions. Moreover, all systems exhibited sustained and near-infrared (NIR) triggered drug release with reduced burst-effect, compared to the release of free bicalutamide. Higher particle size and stronger drug–carrier interactions determined a zero-order kinetics and notably slower release rate of MCN-COOH/B compared to non-functionalized MCN. Cytotoxicity assays on LNCaP prostate cancer cells demonstrated that both MCN/B and MCN-COOH/B possessed comparable antiproliferative activity as free bicalutamide, where MCN-COOH/B exhibited superior efficacy, especially under NIR exposure. These findings suggest that MCN-COOH nanoparticles could be considered as a prospective platform for controlled, NIR-accelerated delivery of bicalutamide in prostate cancer treatment. Full article

The aim of this work was to obtain biochar materials from plant biomass and to determine the changes occurring under the conditions of the pyrolysis process and physical activation, as well as to characterize the physicochemical characteristics of the produced products in terms of their practical use. The pyrolysis process was carried out at a temperature of 700 °C, under the flow of a protective gas, i.e., carbon dioxide, at a rate of 5.0 L/min. The pyrolysis processes were carried out in the absence and presence of an activating agent. For ecological safety, physical activation using water vapor was chosen. In the next stage of the work, biochars were produced and subjected to detailed physicochemical analysis. A scanning electron microscope with energy-dispersive SEM/EDS was used to determine the microstructure and changes in the chemical composition of the biochars. FTIR spectrophotometry was used to identify the functional groups present in the structures of biochars and to indicate changes occurring in the biomass during pyrolysis. Meanwhile, Raman spectroscopy was used to assess the ordering of the biochar structures based on the identification of spectral signals. The description of the specific surface areas of the biochars was made possible by studies conducted using a physical and chemical adsorption analyzer. Based on the obtained research results, the elementary structure, surface development, presence of functional groups on the surfaces of biochars and changes in the structure before and after activation with water vapor were determined. It was found that the biochars had functional groups, a well-developed specific surface area that increased after activation with water vapor, micropores and mesopores, as well as changes in structure under the influence of physical activation. It has been shown that the presence of functional groups influences the hydrogen sulfide sorption capacity. Full article

Six activated carbons from tomato (Solanum lycopersicum L.) stems (TS-AC) were synthesized by carbonization and chemical activation using potassium hydroxide (KOH) and sodium hydroxide (NaOH) at temperatures of 550, 650, and 750 °C. These TS-ACs were then evaluated as adsorbents to remove 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA) from aqueous solutions. The adsorption kinetics of both herbicides followed the pseudo-second-order model, closely correlating with the mesopore volume of the TS-AC. The Langmuir isotherm accurately described the adsorption process for both 2,4-D and MCPA. The porous structure of TS-AC, characterized by micropore volume and specific surface area, significantly influenced the maximum adsorption capacities. The adsorption of both herbicides was pH dependent, but ionic strength had no significant effect. Regeneration testing, conducted over three cycles, showed less than a 15% reduction in herbicide adsorption capacity. This study demonstrates that agricultural waste, specifically tomato stems, can be effectively valorized by using simple activation techniques in TS-AC that are efficient adsorbents to remove organic pollutants, such as herbicides, from aqueous media. Full article

This study presents a novel Basalt-based grafted graphitic carbon nitride composite (Basalt–MTES/g-C₃N₄) for the efficient pretreatment of Cr(VI) in ethylene wastewater. The composite was synthesized by the acid purification of natural Basalt, surface modification with hydroxymethyl triethoxysilane (MTES), and the subsequent grafting of g-C₃N₄. Characterization confirmed the uniform distribution of nano-sized g-C₃N₄ particles on a Basalt surface with intact chemical bonding, where 82.63% of melamine participated in g-C₃N₄ crystallization. The material exhibited a high specific surface area (403.55 m²/g) and mesoporous structure (34.29 nm). Acidic conditions promoted the protonation of amino groups in g-C₃N₄, significantly enhancing Cr(VI) adsorption via ion exchange. Adsorption kinetics followed the pseudo-second-order model, while isotherm data fitted the Langmuir monolayer adsorption mechanism. The composite achieved 97% Cr(VI) recovery through chromatographic extraction and retained 96.87% removal efficiency after five regeneration cycles. This work demonstrates a cost-effective, recyclable green pretreatment material for high-sensitivity Cr(VI) monitoring in ethylene industry wastewater, offering dual benefits in environmental remediation and regulatory compliance. The design synergizes natural Basalt’s stability with g-C₃N₄’s adsorption affinity, showing practical potential for sustainable wastewater treatment technologies. Full article

Ordered mesoporous carbon materials (OMCMs) are widely used as high-performance electrode materials due to their uniform pore structure, excellent electrical conductivity, and good stability. In this paper, three OMCMs with controllable N content were prepared by a nanocasting method using Fe₃O₄ nanocrystals as the template and organic ligands as the carbon source. By adopting a ligand exchange strategy, oleic acid, oleic amine, and octyl amine were successfully capped onto the Fe₃O₄ nanocrystals, respectively, which allowed the rational control of the elemental composition of OMCMs at the molecular level. Further characterizations revealed that the nitrogen content of the resulting OMCMs increased as the proportion of nitrogen atoms in the ligand increased, while the order of the porous structure decreased as the hydrocarbon chain length decreased. This study demonstrates that both the N-doping content and the order of the OMCMs are influenced by the N-containing ligand. This finding will provide a fundamental aspect for their further applications as high-performance electrode and catalytic materials in the field of electrochemistry. Full article

This study reports the synthesis of activated carbon from dwarf elder, a lignocellulosic precursor, yielding a material with a high specific surface area (500.43 m²/g) and mesoporous structure (median pore radius: 3.88 nm). The physicochemical properties of the obtained carbon were characterized using field-emission scanning electron microscopy (FE-SEM), Brunauer–Emmett–Teller (BET) analysis, and Fourier-transform infrared spectroscopy (FTIR), confirming its suitability for aqueous-phase sorption applications. Batch experiments demonstrated carbon’s efficacy in adsorbing amlodipine besylate (AMB), a model pharmaceutical pollutant, with a maximum capacity of 325.9 mg/g under optimized conditions (pH 10.0, room temperature). Systematic evaluation of key parameters, such as initial AMB concentration, sorbent dosage, pH, and agitation speed revealed that sorption kinetics adhered to pseudo-second-order and Elovich model. The high efficiency of the synthesized carbon material, coupled with its low-cost and eco-friendly synthesis, positions it as a promising candidate for the scalable remediation of AMB and structurally related pharmaceuticals from contaminated water sources. Full article

This study investigated the enhanced adsorption capacity of a silver nanoparticle (AgNPs)-incorporated tamarind seed activated carbon nanocomposite (Ag/TSAC) for the elimination of methyl orange (MO) from aqueous solutions. The nanocomposite was analyzed using TGA, SEM, FTIR, and BET, revealing a mesoporous structure with a surface area of 54.92 m²/g. The results showed that the structure of tamarind seeds altered during pyrolysis, as shown by the loss of many functional groups and a weight decrease of 66.61% in the nanocomposite. The efficiency of the nanocomposite in eliminating MO was assessed by batch adsorption studies, which also examined the effects of solution pH, starting MO concentration, and nanocomposite dose. The best MO removal was seen at pH 2, indicating a positive electrostatic interaction between the dye and adsorbent. The results demonstrated that the Ag/TSAC nanocomposite significantly enhanced MO removal efficiency from 19% to 96% under optimal adsorptive conditions, due to the synergistic effect of the high surface area of activated carbon and the enhanced adsorption sites provided by the AgNPs. The study demonstrates the potential of Ag/activated carbon nanocomposite as a sustainable adsorbent for removing MO dye from wastewater using a second-order model and Langmuir model. Full article

Nickel-decorated carbocatalysts were synthesized by the evaporation-induced self-assembly (EISA) method. The influence of the metal content and pyrolysis temperature upon the photoactivity was assessed through rhodamine B degradation under UV irradiation. The characterization revealed a mesoporous framework with a granular morphology composed of amorphous carbon, where the pyrolysis temperature influenced the metal dispersion on the carbon surface. The primary metallic phases consisted of elemental nickel crystallites and nickel carbide phases. The kinetic parameters for adsorption and dye photodegradation under UV irradiation were determined and compared to TiO₂-P25. Correlations were found between the adsorption parameters, photocatalytic activity, and nickel content, the pyrolysis method (one-step vs. two-step pyrolysis), and the pyrolysis temperature. The sample with a 1:1:0.25 tannin/Pluronic^®F-127/Ni weight ratio pyrolyzed at 700 °C exhibited the highest photoactivity, achieving rhodamine B degradation rates up to 68 and 2.5 times greater than photolysis and TiO₂-P25. In terms of the normalized weight of the catalysts, it can be concluded that the present Ni-based catalysts are up to two orders of magnitude more photoactive than TiO₂-P25 under UV irradiation, opening a door for indoor UV-driven photoreactors. These findings demonstrate that the EISA method is an effective, low-cost, and ecofriendly approach for synthesizing Ni-decorated carbocatalysts. Full article

Ensuring effective water purification is essential for addressing freshwater scarcity and achieving the United Nations Sustainable Development Goals (SDGs). An efficient hybrid mixture, composed of FeCr quantum dots doped into mesoporous silica SBA-15 support and activated carbon (AC) derived from olive mill solid wastes, has been developed for treating high optical density polluted aqueous environments. This hybrid, denoted as FeCr-SBA-15/AC, was examined for its efficacy in the adsorption and photo-Fenton degradation of met orange dye (MO), a model high-optical-density pollutant, under visible light exposure. Characterization of the prepared samples was conducted using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) surface area analysis, diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Key parameters investigated included catalyst dosage, dye concentration, solution pH, and H₂O₂ concentration. Remarkably, the FeCr-SBA-15/AC hybrid exhibited superior photocatalytic activity, achieving a degradation efficiency of 97% for MO under optimized conditions (catalyst dosage = 0.75 g L⁻¹, dye concentration = 20 mg L⁻¹, pH = 5.47, and 0.5 mL H₂O₂) after 180 min of irradiation with visible light. This performance surpassed that of FeCr-SBA-15 alone by 20%, due to the synergistic effects of adsorption and photo-Fenton. The adsorption of MO onto AC followed the Freundlich model equilibrium isotherm, while the experimental data for the hybrid mixture aligned well with the pseudo-first-order Langmuir–Hinshelwood kinetic model with a rate constant of 0.0173 min⁻¹. The leaching of Cr in the solution was very low—0.1 ppm—which is below the detection limit. These findings underscore the potential of the synthesized FeCr-SBA-15/AC hybrid as a cost-effective, environmentally friendly, and highly efficient photo-Fenton catalyst for treating wastewater contaminated by industrial effluents. Full article

Low-cost powdered activated coke (PAC) produced by a one-step rapid method with lignite was used as an adsorbent for the advanced treatment of phenol-containing wastewater to evaluate the feasibility of replacing high-cost commercial powdered activated carbon. Characterization using infrared spectral analysis, SEM, and BET showed that the PAC mesopores were well developed. PAC exhibited a high adsorption performance for phenol in static experiments. The adsorption was almost in equilibrium within 20 min, and the removal efficiency reached 85.4% with 1.5 g L⁻¹ PAC and 99.9% with 4 g L⁻¹ PAC. As common components in wastewater, NaCl and Na₂SO₄ did not exhibit significant competitive adsorption with phenol in PAC. The adsorption process occurred in accordance with the Langmuir model and the pseudo-second order kinetic model. Furthermore, the effects of hydrothermal regeneration on PAC adsorbing phenol were studied, and the adsorption capacity of PAC after five regeneration cycles was 86.1% of that of the new PAC, which still had good adsorption performance. PAC offers significant advantages in terms of adsorption capacity, economic feasibility, regeneration, and recycling, providing a practical solution to the problem of phenol-containing wastewater pollution. Full article

Dye wastewater poses significant risks to human health and aquatic ecosystems, necessitating efficient remediation strategies. This study developed a magnetic Fe₂O₃ nanocomposite (MNC) derived from phosphoric acid-treated walnut shell biomass carbon to remove Alizarin red S (AR) dye from polluted water. Characterization techniques confirmed the nanocomposite’s mesoporous structure, superparamagnetic properties (61.5 emu/g), and high crystallinity. Optimization using Response Surface Methodology (RSM) revealed a maximum adsorption efficiency of 94.04% under the following optimal conditions: A pH of 2, AR dye concentration of 85 mg/L, adsorbent dose of 1.5 g/L, and particle size of 448.1 nm. Adsorption followed pseudo-second-order (PSO) kinetics (R² = 0.9999) and Langmuir isotherm models (R² = 0.9983), with thermodynamic studies indicating spontaneous and endothermic chemisorption. The intra-particle diffusion model, Bangham, and Boyd plots describe the adsorption process, and external boundary layer diffusion of AR dye molecules in the aqueous phase limits the adsorbate removal rate. Regeneration tests demonstrated reusability over three cycles, with a desorption efficiency of 50.52% using 30 mM HCl. The MNC exhibited a maximum adsorption capacity (Q_max) of 115.35 mg/g, outperforming other adsorbents, making it an efficient and sustainable alternative solution for AR dye removal from water bodies. Full article

This study investigates the activation mechanisms of hydrogen peroxide (H₂O₂) using iron-activated carbon (Fe²⁺/H₂O₂/AC) for the efficient degradation of amoxicillin (AM) in wastewater. The system achieved a high degradation efficiency of 90% under alkaline conditions (pH 9), with singlet oxygen (¹O₂) and hydroxyl radicals (^•OH) identified as the dominant reactive species through scavenger experiments. High-performance liquid chromatography–mass spectrometry (HPLC-MS) analysis revealed degradation by-products and proposed reaction pathways, including the loss of amine groups, ring-opening oxidation, and bond cleavage. The structural and morphological properties of Fe²⁺/H₂O₂/AC were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analysis. The BET surface area of Fe²⁺/H₂O₂/AC was determined to be 128.36 m²/g, with a mesoporous structure facilitating efficient mass transfer and adsorption. The system was systematically evaluated under varying conditions, including H₂O₂ concentration (25–250 mg/L), catalyst dosage (0.05–1.0 mg/L), and pH (3–10). Kinetic analysis revealed that the degradation process follows pseudo-second-order kinetics (R² = 0.966), while adsorption isotherms were best described by the Langmuir model (R² = 0.98). Ecotoxicity tests indicated that the degradation products are less harmful to aquatic organisms. The system demonstrated excellent stability over three consecutive cycles, highlighting its potential for long-term application in treating pharmaceutical-contaminated wastewater. Full article

Under the concept of green and low-carbon development, efficient and environmentally friendly biochar preparation methods have attracted much attention. This study assessed a novel sodium carbonate activator combined with acid modification for sludge-based biochar (SB) production and its adsorption of organics in wool scouring wastewater. Under 600 °C, the optimal carbonization temperature, the residual weight percentage of biochar carbonized material increases from 27% to 73% after Na₂CO₃ activation compared to ZnCl₂ activation. Compared to HCl-modified ZnCl₂-activated biochar (Zn-Cl-SB), HCl-H₂SO₄-modified Na₂CO₃-activated biochar (Na-Cl/S-SB) had a specific surface area of 509.3 m²/g, and the average mesopore size was 7.896 nm, with micropore volume and specific surface area increasing by 83.3% and 79.8%, respectively. Meanwhile, the C-O oxygen-containing functional groups and pyrrole nitrogen-containing functional groups were significantly increased. Na-Cl/S-SB exhibited an excellent adsorption performance for organic matter in wool scouring wastewater, with a maximum adsorption capacity of 168.3 mg/g. Furthermore, the adsorption process followed the pseudo-second-order kinetic model. Three-dimensional fluorescence spectrum analysis showed that Na-Cl/S-SB had a strong adsorption capacity for aromatic protein analogs, proteins containing benzene rings, and dissolved microbial by-products in wool scouring wastewater. This study will serve as a guideline for the green synthesis of SB while improving its ability to adsorb pollutants. Full article

Metal nanoparticles supported in carbon materials are the traditional electrocatalyst currently used in many applications. However, these composite materials have many problems associated with the optimization of both components for the specific application, besides the stability of the mixture. Self-supported metallic materials may be an interesting strategy in order to avoid the traditional carbon supports; however, these metallic materials should present highly active surface area. Iron aerogels are presented in this work as effective and affordable unsupported electrocatalysts. The combination of their metallic structure with high porosity (i.e., 85 m² g⁻¹ and 0.45 cm³ g⁻¹ of mesopore volume), due to their interconnected tridimensional structure, leads to a great activity versus the oxygen reduction reaction. A method for producing iron aerogels based on microwave-assisted sol–gel methodology is presented. The incorporation of carbon functionalities to the iron aerogels seems to clearly influence the mechanism of the reaction, favoring the direct mechanism of the oxygen reduction reaction and thus notably improving the performance of the electrocatalysts. Chemical vapor deposition seems to be an adequate methodology for incorporating carbon functionalities to the transition metal structure without affecting the tridimensional network and leading to current densities over 4 mA cm⁻² and great stability even after 10,000 s. Full article