Specific Area Research Articles

Adsorption Performance and Photocatalytic Activity of La-TiO2@kaolin Composites

Abstract La-TiO2@kaolin(LTK) composites were prepared via sol-gel method with kaolin, lanthanum nitrate and tetrabutyl titanate as raw materials. The samples were characterized by XRD, SEM/EDS, and UV-Vis. The visible light photocatalytic reduction activity and adsorption performance of samples for Cr(VI) were studied. The results showed that La doping can refine TiO2 grains, stabilize phase structure of anatase TiO2, and expand its absorption spectrum, thereby enhancing its photocatalytic reduction activity. Due to the composite of kaolin, the dispersion of TiO2 is improves and it is endowed with a large specific surface area lead to enhance its adsorption ability for Cr(VI). The adsorption equilibrium process of LTK for Cr(VI) conforms to the Langmuir equation model. The coupling effect of doping and composite modification improves the adsorption and visible light catalytic reduction activity of Cr(VI) over composite material samples. The adsorption-photocatalytic removal rate of LTK for Cr(VI) under visible light irradiation for 6 hours reached the highest of 96.5%. The apparent first-order kinetic constant of its photocatalytic reduction reaction was 2.6 times that of pure TiO2.

Study on the effect and mechanism of support structure and characteristic on Ag-based catalysts for low-temperature selective catalytic oxidation of ammonia

Herein, the influence of support type and properties on the catalytic activity and selectivity of Ag-based NH3-SCO catalyst was studied through the evaluation of NH3-SCO performance, the physicochemical characterization of H2-TPR, NH3-TPD, N2 isothermal adsorption–desorption, XPR and XPS, and the mechanism study of 1H MAS NMR, In-situ DRIFTS and DFT calculations. Ag/nano-TiO2, Ag/Al2O3, and Ag/MnO2 all showed better NH3-SCO activity because of more abundant Brønsted and Lewis acid sites of Al2O3 and TiO2 and more actual Ag loading amount due to the larger specific surface area and suitable surface chemistry. The N2 selectivity of Ag/nano-TiO2 is significantly better, which may be due to the highly dispersed Ag species and the abundant Brønsted acid sites with higher N2 selectivity. The mechanism study showed that the terminal hydroxyl was the preferred consumption target of Ag species, and this consumption promoted the effective dispersion and stable anchoring of Ag on the TiO2 surface.

Synergistic photocatalytic degradation of methylene blue using TiO2 composites with activated carbon and reduced graphene oxide: a kinetic and mechanistic study

This comprehensive study explored the removal of methylene blue (MB) from aqueous solutions as a model pollutant, utilizing solar-driven photocatalysis with nano-sized titanium dioxide (TiO2) and composites with activated carbon (AC) and reduced graphene oxide (RGO). This research introduces continuous solar reactor instead of conventional batch experiments investigating its design configuration. Utilizing response surface methodology (RSM), the study determined the optimal process conditions (MB concentration at 30 mg/L, pH 8.82, irradiation time 138 min), under which TiO2 achieved a 93.13% MB removal efficiency. The study further revealed that the integration of TiO2 with AC and RGO (5% wt.) significantly enhanced the MB photocatalytic degradation. The TiO2/AC composite achieved 98.3% MB degradation in 138 min of solar exposure, related to its large specific surface area of 146 m2/g and a pore volume of 0.439 cm3/g. Likewise, the TiO2/RGO composite demonstrated 97% removal with a surface area of 102 m2/g and a pore volume of 0.476 cm3/g, significantly better than nano-TiO2. Additionally, the research investigated the role of the solar reactor configuration on MB removal. Using 26 mm Pyrex tube diameter with 15 cm long on parabolic aluminum concentrator inclined at 30° optimally achieved the peak MB degradation efficiency. Recyclability tests shown a noticeable decrease in nano-TiO2 efficiency to 56.03% without regeneration; however, after regeneration following the third cycle, the efficiency significantly recovered to 70.07%. Thereby, this paper introduces an innovative, continuous, and well-designed solar reactor system for dye removal, employing nano-TiO2 and its composites with AC and RGO for improved photocatalytic efficiency under statistically optimized process conditions.

CFD simulation of liquid-liquid extraction mechanism and enhancement schemes in microchannels based on three mass transfer models

Microreactors are highly efficient devices with a large specific surface area to improve the mass transfer efficiency. In this paper, a comprehensive three-dimensional CFD model was constructed based on three mass transfer theories to simulate the liquid-liquid two-phase flow and mass transfer process in a microchannel reactor, and two enhancement schemes were proposed. The multiphase flow and mass transfer characteristics were investigated by visualization and extraction experiments. The results indicated that the extraction efficiencies (E) and overall mass transfer coefficients (KLa) calculated by the penetration model and surface renewal model were within ±15 % errors compared to the experimental values. Moreover, E primarily increases with the increase of fluid residence time, while KLa increases with increasing flow rate. As the flow rate increases from 0.3 ml/min to 1.5 ml/min, E decreases by 15 %, and KLa rises from 0.78 s⁻¹ to 2.65 s⁻¹. Whereas the channel width decreases from 0.8 mm to 0.3 mm, E decreases by 3 %, and KLa rises from 0.44 s⁻¹ to 2.77 s⁻¹. Finally, microchannel with necked structure and baffles in mixing zone both improve the mass transfer efficient to some extent.

Adsorption of dibenzofuran by modified biochar derived from microwave gasification: Impact factors and adsorption mechanism

Dioxins, emanating from the waste incineration, constitutes an organic pollutant that poses considerable risks to the human health and environment. In this study, the corn straw char (CSC) and oak char (OC) derived from the electric heating or microwave gasification, and the coconut-shell activated carbon (AC) are employed as absorbents for the adsorption of dibenzofuran (DBF, dioxins model compound). Characterization techniques, including BET, X-ray CT, SEM-EDS, FTIR, and XPS, are performed to identify the DBF adsorption mechanism on the biochar. The results show that the biochar prepared by the microwave gasification has a more well-developed pore structure than that of the electric heating gasification. The higher porosity (16.94 %) and lower mineral content (1.75 %) are responsible for the effective adsorption of DBF onto AC. The adsorption capacity of CSC is proportional to the modified concentration of KOH. It is mainly ascribed to the decrement of carboxyl and lactone groups and the enhancement of alkaline functional groups on the biochar surface, which augments the hydrophobicity and π–π electron donor–acceptor (EDA) interaction. Instead, DBF adsorption capacity on the biochar is adversely affected by the HNO3 modification. For all biochar samples, the corresponding maximum adsorption ratios are AC (87.11 %) > KOH-modified CSC (77.14 %) > unmodified CSC (49.11 %) > unmodified OC (39.70 %) > HNO3-modified CSC (36.09 %). The adsorption mechanisms of DBF on the gasified biochar encompass the pore filling, hydrophobicity, and π–π EDA interaction. A desirable adsorption capacity of DBF on the biochar prepared by the microwave gasification is attainable through augmenting the specific surface area while diminishing the oxygen-containing groups of the surface simultaneously.

Ultra-fine carbon decorated TiO2/C/g-C3N4 hybrid for strong physical adsorption and efficient photodegradation of pollutants

Enhancement in the visible light absorption and efficient interfacial charge transfer is crucial for optimizing photocatalytic efficiency in the degradation of pollutants such as methyl orange (MO) and formaldehyde. This study focuses on the properties of a TiO2/C/g-C3N4 hybrid efficient photocatalyst is developed by employing an air calcination method to deposit graphitic nitride (g-C3N4) onto a carbon-modified TiO2 surface. The characterization techniques, including high-resolution transmission electron Microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), were used to provide a comprehensive understanding of the material’s structural, morphological, thermal, and chemical properties. This hybrid catalyst is specifically engineered for the efficient decomposition of methyl orange (MO) and formaldehyde, demonstrating a significant increase in photocatalytic activity. The TiO2/C/g-C3N4 photocatalyst also exhibits an enhanced specific surface area of 181.2 m2/g, which facilitates increased physical adsorption and photo-catalytic active sites. Experimental results confirm that this catalyst effectively adsorbs MO physically even in the dark without degradation. Combining physical and photo-catalytic functions, this catalyst degrades 94 % of MO within 180 min with the initial concentration 0.2 mol/L of MO, and achieves almost 100 % decolorization of MO under visible light irradiation. Notably, the catalyst retains its high activity after 4 cycles of MO degradation, underscoring its durability and consistent performance. Additionally, the hybrid catalyst features a staggered type-II energy level configuration, which effectively enhances charge separation and boosts photocatalytic efficacy. The incorporation of an ultrafine carbon layer further augments electron mobility towards the surface, crucial for effective catalytic reactions. This study paves the way for future development of highly efficient photocatalytic materials for environmental purification.

Rheological and adhesive improvements of terminal blend rubberized asphalt via fumed silica nanoparticle modification

Due to the high degree of desulfurization and depolymerization of crumb rubber (CR) particles in terminal blend rubberized asphalt (TBRA), their elasticity and adhesive performance are insufficient. To address this, the study utilized low-cost fume silica nanoparticles (FSNPs) to enhance the elasticity and adhesive properties. TBRA binders with varying CR contents (30 %, 40 %, 50 %) were modified using different dosages of FSNPs (2 %, 4 %, 6 %). The microstructure of FSNPs was examined through TEM and SEM. Using a dynamic shear rheometer (DSR) test, contact angle test, and atomic force microscope (AFM) test, the effects of FSNPs on the rheological properties, surface energy, and adhesive properties of TBRA binders were evaluated. The results showed significant improvements in the deformation resistance and elasticity of the TBRA binders modified with FSNPs. This is attributed to the branched network structure of FSNPs, which notably enhances the binder's cohesion, thereby strengthening its resistance to shear deformation and improving elasticity. FSNPs effectively reduce the moisture sensitivity of TBRA, due to the hydrophilic hydroxyl groups on FSNPs being replaced by hydrophobic methyl groups (-CH3). The inadequate bonding performance of TBRA can be attributed to the high levels of extensively depolymerized and desulfurized CR particles, which reduce the cohesiveness of the binder. The addition of FSNPs, although it lowers the surface energy of TBRA binders, significantly enhances their cohesiveness due to the branched network structure, thereby improving their bond performance. AFM results indicate that FSNPs enhance the adhesive strength of the TBRA binder surface due to their high specific surface area, which provides more van der Waals forces and electrostatic interactions. For economic efficiency, an addition of 4 % is recommended for TB30, and 2 % for TB40 and TB50. At these specified concentrations, the bond strength of the TBRA binder can be increased by 45–55 %.

Formation of bovine serum albumin-galangin nanoparticles and their potential to inhibit ROS-induced inflammation: Enthanol desolvation vs. pH-shiftng method

pH-shifting method, as an eco-friendly approach, is a promising alternative to desolvation method, yet systematic comparison of their property is still lacking. In this study, bovine serum albumin-galangin nanoparticles (BSA-GA NPs) were designed for alleviating ROS-mediated macrophage inflammation by the 2 separate methods. Compared with the desolvation method, BSA exhibited a higher loading capacity for GA under the pH-shifting method, which was attributed to the exposure of the binding site leading to enhanced affinity for GA and a more compact particle structure. Further analyses evidenced that the electron arrangement and crystal structure of GA changed with different methods. The content of random coil of BSA was elevated after pH-shifting method. Besides, the smaller size rendered the pH-shifting treated BSA-GA NPs easier to be taken up by macrophages, while the enhanced specific surface area conferred excellent ROS scavenging and anti-inflammatory performances. This study may provide new insights into the choice of loading methods.

Nitrogen functionalized biomass derived mesoporous carbon nanomaterials for electrochemical detection of lead (II) ions

This study has explored the sustainable solution after designing an economical metal-free biomass-derived nanocarbon for the selective sensing of lead. The nitrogen and sulfur-rich mesoporous nanocarbon is designed through a facile hydrothermal-assisted thermal annealing method. The high-temperature treatment gave nanocarbon unique carbon dot decorated layered morphology, while nitrogen and sulfur precursor thiourea and melamine strengthened the nanomaterial stability, sensitivity, and selectivity toward lead metal ions. The high specific surface area of mesoporous nanocarbon viz., 1671.93 m2/g with the pore width and pore volume of 2.02 nm and 0.476 cm3/g has enhanced the conductivity of as-synthesized sensor, which helps in increasing sensitivity toward lead. The high conductivity was also confirmed through cyclic voltammetry, where an 80 % increment in current was observed in the case of the modified electrode when compared with bare GCE. The differential pulse normal voltammetry and differential pulse anodic stripping voltammetry were performed to calculate the detection limit, where an excellent detection limit of 22 nM was obtained from the DPASV technique. Moreover, the nanomaterial was also tested for detecting lead in tap water. The as-synthesized nanocomposite is highly efficient and selective for the detection of lead. This study will motivate the researchers to engineer sustainable and efficient devices for sensing metal pollutants.

Accelerated carbonation curing of biochar-cement mortar: Effects of biochar pyrolysis temperatures on carbon sequestration, mechanical properties and microstructure

The integration of biochar with accelerated carbonation curing (ACC) has the potential to reduce the carbon footprint of cementitious materials. However, the effects of biochar pyrolysis temperatures on the performance of accelerated carbonation-cured cementitious materials remain unclear. In this study, corn straw was used as the raw material to prepare biochar at 300℃, 500°C, and 700°C for incorporation into cement mortar. The effects of biochar pyrolysis temperatures on carbon sequestration, mechanical properties and microstructure of cement mortar were investigated at 3 days and 28 days of ACC. The results showed that incorporating the biochar at 500℃ into cement mortar exhibited the highest carbon sequestration with up to 31.6 % increase compared to 300℃ and 700℃. The porosity of biochar dominated the inward CO2 transport rather than the chemisorption effect of oxygen-containing functional groups under ACC. The biochar at 500℃ showed the most improvement in compressive strength. The biochar at 700℃ enhanced the early-stage compressive strength due to its significant hydrophobicity at high dosages (7 % by mass), while excessive amounts adversely affected the overall compressive strength. The incorporation of biochar effectively reduced the porosity of cement matrix and narrowed the differences in carbonation degree among layers, with the biochar at 500 °C showing the best results due to its larger specific surface area and pore volume. This study provides insights to further advance the efficient application of biochar in low-carbon building materials.

Assembly and operation optimization of proton exchange membrane water electrolyzer for performance enhancement

Abstract Proton exchange membrane water electrolysis (PEMWE) for hydrogen production possesses wide-ranging and rapid dynamic response capabilities, offering promising applications in the consumption of new energy sources and the dynamic balancing of power grids with a high proportion of renewable energy. The assembly and operating conditions of PEMWE significantly affect its performance. Therefore, thoroughly studying and understanding the influence of PEMWE’s assembly and operating conditions on water electrolysis performance are crucial for enhancing PEMWE’s performance and promoting its applications. In this research, the influence of installation preload torque, feedwater flow rate, and operating temperature on the performance of the electrolyzer, including the electrochemical active specific surface area (ECSA), high-frequency resistance (HFR) and various types of polarizations (including activation polarization, ohmic polarization, and mass transfer polarization) during the operation of the electrolyzer, were detailedly investigated. The results showed that the optimal preload torque and operating temperature for the electrolyzer were 3 Nm and 80°C. Under these conditions, an optimized PEMWE performance would be achieved by ensuring that the feedwater flow rate exceeded the water consumption during electrolysis.

Cr-MIL-101 derived nano Cr2O3 for highly efficient dehydrogenation of n-hexane

Nano Cr2O3 (n-Cr2O3) was prepared by the thermolysis of the mesoporous Cr-MIL-101, and its catalytic performance for n-hexane dehydrogenation was investigated and compared with Cr2O3 obtained by traditional method. It is found that dehydrogenation of n-hexane on n-Cr2O3 catalyst can produce n-hexenes and benzene efficiently, and the catalytic performance is related to the calcination temperature. The optimal n-hexane conversion can be obtained on n-Cr2O3 calcinated under 600 °C, is 40.6%, and the selectivities to n-hexenes and benzene are 20.1% and 69.3%, respectively. The conversion of n-hexane for n-Cr2O3 catalyst is decreased with calcination temperature increase, while the catalyst stability in dehydrogenation reaction is enhanced. n-Hexane conversion of p-Cr2O3-1 (obtained by precipitation method) and p-Cr2O3-2 (calcinating Cr(NO3)·9H2O directly) catalysts are very low (<7.5%), and their specific activity for n-hexane dehydrogenation are 1.5 and 1.7 g/(m2·h) respectively, lower than that of n-Cr2O3-600 (2.0 g/(m2·h)). The results of BET, XRD, TEM and FT-IR reveal that n-Cr2O3 is the nanoparticles with large specific surface area that more dehydrogenation active sites are exposed, while p-Cr2O3 is the large particles with extremely low surface area that few dehydrogenation active sites are presented. By contrast, industrial Cr2O3/Al2O3 catalyst possesses the highest specific activity of 2.4 g/(m2·h) due to the dispersion effect of Al2O3. Therefore, highly catalytic activity of n-Cr2O3 for n-hexane dehydrogenation is attributed to the unique properties of small particle, large specific surface area and more exposed active sites. This work not only explains the high dehydrogenation activity of nano-Cr2O3 derived by Cr-MIL-101, but also provides guidance for the precise design and synthesis of high-performance CrOx-based catalyst for the dehydrogenation of alkanes.

Metal Ions Modified Azo‐Linked Porous Polymers for High Performance CO2 Capture

AbstractPorous polymer show great potential for CO2 capture owing to its high specific surface area, adjustable porous structure and chemical structure. Herein, a novel CO2 adsorption materials ALP−M (M: Cu2+, Mg2+, Ni2+) were prepared through coordination between azo‐linked porous polymer (ALP) synthesized by oxidative coupling polymerization of tris(4‐aminophenyl)amine and metal ions. The structures and morphology of as‐prepared materials were demonstrated by FT‐IR, XRD, XPS, BET and SEM, the CO2 capture performance and mechanism of ALP−M were also investigated through static adsorption and column adsorption experments, the results show that metal ions can enhance the CO2 adsorption and desorption performance of ALPs by coordination adsorption. ALP−M showed a highest static CO2 adsorption capacity of 2.67 mmol g−1 at 273 K (1 bar), which is 35.5 % higher than that of ALP. The metal ions served as Lewis acid sites can enhance the affinity of adsorbent for CO2. In column adsorption experiments, the ALP−M showed a higher saturated adsorption capacity 4.99 mmol g−1 at 273 K (1 bar) than that of static adsorption, and excellent cycling stability after 500 adsorption and desorption cycles, the adsorption capacity retention rate of ALP−M for CO2 can reach 98 %.

Enhancement and mechanism of mechanical properties and functionalities of polyacrylamide/polyacrylic acid hydrogels by 1D and 2D nanocarbon

Highly flexible hydrogels are widely used in fields such as agriculture, drug delivery, and tissue engineering. However, the simultaneous integration of excellent mechanical properties, swelling properties, and high electrical conductivity into a hydrogel is still a great challenge. This work introduces 1D tubular multi-walled carbon nanotubes (MWCNTs) and 2D layered graphene oxide (GO) into polyacrylamide/poly-acrylic acid (PAM/PAA) hydrogels. The high specific surface area and oxygen-containing groups of GO contribute to excellent mechanical properties and water absorption of the PAM/PAA hydrogels, but the conductivity is poorly affected due to the presence of defects on GO surface. However, MWCNTs with large aspect ratios benefit to form continuous conductive paths in PAM/PAA hydrogels which further improves conductivity of the hydrogels. MWCNTs are entangled with PAM/PAA molecular chains to form a dense three-dimensional (3D) network structure, and this special structure improves the water absorption of PAM/PAA hydrogels by 3.7 g g−1. What’s more, the MWCNTs/PAM/PAA hydrogel not only provides excellent mechanical properties (compressive strength up to 2.7 MPa), but also has high conductivity (2.3 S m−1). In particular, a strain sensor based on MWCNTs/PAM/PAA hydrogel exhibits exceptional sensitivity (gauge factor = 3.9 at 230–300 % strain) with a rapid response (200 ms) over a wide strain range (50 ∼ 200 %) which enables the ability to precisely and reliably monitor human motion. Therefore, the work provides a new insight into the design of multifunctional hydrogels with application on anatomical water plugging, electronic skin, and biosensors.

Dual electric field and defect engineering induced multi-channel electron transfer for boosting photocatalytic hydrogen production on Cu2+-doped ZnMoO4/ZnIn2S4 heterojunction

Serious recombination of photogenerated carriers is the bottleneck problem of achieving high-performance photocatalytic reaction. A high efficient Cu2+-doped ZnMoO4/ZnIn2S4 (CZMOZIS) heterojunction was synthesized by hydrothermal method. The CZMOZIS heterostructure achieved hydrogen production of 11637.5 µmol g−1 within 5 h, which was 9.7 times higher than that of pure ZnIn2S4. Comprehensive characterization and theoretical calculation demonstrated that the CZMOZIS composites exhibited broad light absorption, an increased specific surface area and an optimized Gibbs free energy. The presence of oxygen vacancies in CZMOZIS composites was confirmed by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy, revealing the formation of defect levels below the conduction band (CB) of ZnMoO4. Kelvin probe force microscopy (KPFM) and Zeta potential demonstrated that the intrinsic electric field (IEF) of the CZMOZIS heterojunction was enhanced, which may be attributed to the generation of polarization electric field (PEF). The double electric field provided a robust driving force for the photogenerated carrier migration and separation. The electrons in the CB and defect levels of Cu2+-ZnMoO4 could be coupled with the holes of ZnIn2S4, thereby forming a multi-channel electron transfer. This work provides a theoretical support for promoting charge transfer to improve photocatalytic performance by dual electric field and defect engineering.

Polyaniline nanoparticles intercalated Ti3C2 MXene reinforced waterborne epoxy nanocomposites for electromagnetic wave absorption and anticorrosion coating applications

Ti3C2 MXene (TM) has great application potential in the field of wave absorption and corrosion resistance due to its unique performance, such as high specific surface area, high electrical conductivity, excellent mechanical and good chemical stability. However, it is difficult to obtain uniformly dispersed TM in the resin matrix due to rapid agglomeration behavior. It is difficult to obtain uniformly dispersed Ti3C2 MXene (TM) in the resin matrix due to rapid agglomeration behavior. Heren, a novel method is presented to improve the corrosion protection and dispersion of TM by polymerizing polyaniline (PANI) nanoparticles between layers. The waterborne epoxy (WEP) coating with PANI-TM had high mechanical properties including impact resistance, adhesion, and flexibility and wear resistance. The PANI-TM-WEP composites can effectively absorb more than 90 % of the electromagnetic waves and demonstrate a decreased glass transition temperature of WEP from 128.0 to 107.6 ℃. Moreover, the |Z|0.01Hz value of the PANI-TM0.5 % was 1.2369 × 106 Ω·cm2, which was one order of magnitude larger than WEP coating. The high-performance anticorrosion of PANI intercalated TM coating is attributed to the synergistic effect of impermeable TM nanosheets and passivation effect of PANI. Therefore, PANI-TM is a potential choice for applications in the fields of anticorrosion and microwave absorption.

Mesoporous carbon nanospheres doped with rich non-metallic and metallic catalytic active sites: A high-performance electrochemical platform for sensing of chloramphenicol in food samples

The development of a low-cost, accurate sensing strategy for trace levels of chloramphenicol (CAP) residues in food is crucial but remains challenging. In this study, a high-performance electrochemical platform was developed to detect CAP in animal-derived foods using Ni2P embedded N, P-co-doped mesoporous carbon nanospheres (Ni2P@N,P-MCS). The Ni2P@N,P-MCS material, with a unique mesoporous structure and large specific surface area, exhibited excellent adsorption properties. The N, P-co-doped heteroatoms enhanced the electric conductivity and active centers of MCS, facilitating fast mass transport and electron transfer. The introduction of Ni2P increased the active sites and enhanced the electrocatalytic activity. Leveraging these advantages, the electrochemical sensor based on Ni2P@N,P-MCS demonstrated outstanding detection performance with a wide linear range from 0.04 to 250 μM and a low limit of detection of 12 nM. The sensor also showed good reproducibility, stability, and anti-interference properties. Furthermore, the sensor was successfully tested in milk and pork samples, showing satisfactory recovery rates and indicating its feasibility for real sample analysis.

Bleached cellulose biochars as a sustainable alternative for oilfield-produced water (OPW) treatment and environmental remediation

Eucalyptus, a renewable and fast-growing raw material widely used in the paper industry, has great potential for new applications beyond papermaking. Bleached eucalyptus pulp, traditionally used in the pulp industry, has proved to be a promising alternative for removing complex organic compounds such as naphthenic acids (NAs), often found in oil-produced water (OPW). This study aimed to optimize the production of biochars from bleached eucalyptus pulp through pyrolysis at 700, 800, and 900 °C and to correlate the resulting properties with the ability to adsorb NA at low concentrations and in acidic and alkaline media. The research explores realistic environmental scenarios where naphthenic acids may be present in dilute concentrations after initial treatments. The biochars were characterized by their micro and mesoporous structures, amorphous structures, and distinct functional groups and were evaluated in simulated effluents. Biochar B900 reached a maximum adsorption capacity of 35 mg/g at pH 4 and 25 °C, excelling in acidic environments, while at pH 8, biochar B700 showed better performance. The PVSDM model revealed that mass transfer and pore diffusion coefficients increased with increasing pyrolysis temperature. The Langmuir model was the best fit for the experimental data. The biochar produced at 900 °C had the highest specific surface area (1,041.55 m2/g) and pore volume (0.56 cm3 g−1), favoring its adsorption capacity. Although the biochar shows good initial efficiency, the progressive reduction in adsorption capacity over the cycles suggests limited reusability, highlighting the need for optimization in the regeneration process to improve its economic viability in wastewater treatment.

Developing adjustable micro- and mesopore structured carbon materials from wood via biotechnology for enhanced capacitive deionization

Capacitive deionization (CDI) has attracted significant investigation interest for its potential in low-cost, efficient, and non-selective ion removal. However, achieving high performance in adsorption capacity and efficiency remains challenging, particularly with conventional biomass-derived electrodes. In this study, we developed adjustable, intricately porous, and hydrophilic wood-derived nanocarbon electrodes for electrochemical deionization. Our approach utilized biological pretreatment white-rot fungi, followed by chemical activation, effectively disrupting the rigid crystalline-amorphous structure of wood to create open micro-mesoporous networks. The resulting CDI carbon electrodes featured a predominance of micropores (especially below 0.8 nm) and a pronounced mesoporous arrangement, with a specific surface area of 1788 m2/g and 48 % meso-porosity. Additionally, this process enhanced surface oxidation and nitridation, resulting in surfaces rich in oxygen- and nitrogen-containing functional groups. These characteristics enable the electrodes to achieve a maximum adsorption capacity of 28.78 mg/g within 30 min, outperforming the performance of common biomass-derived electrodes. Moreover, the electrodes demonstrated excellent adsorption capacities for other contaminants, including 29.76 mg/g for NaF, 30.12 mg/g for Cd(NO3)2, and 27.24 mg/g for Pb(NO3)2. This study offers a cost-effective and viable alternative to current CDI electrodes, advancing the field by providing a viable solution to the limitations of existing technologies.

Highly efficient oxygen carrier NiFeP (oxy) hydroxides nanoparticle embedded in N-doped porous carbon derived from bio-waste for bifunctional electrocatalysts

Developing cost-effective, readily available materials for efficient hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water splitting is a crucial step toward enhancing the profitability and sustainability of energy conversion systems. This research introduces a novel synthesis method for NiFeP/NPC OHs from banana peel bio-waste, a method that could revolutionize the field of materials science and electrochemistry. The use of metallic phosphides, known for their excellent electrical conductivity and catalytic activity, as bifunctional catalysts, combined with the efficient synthesis of nanoporous carbons (NPC) from banana peel bio-waste (BPW), could pave the way for a new era of sustainable and cost-effective energy conversion. By chemically activating different porogens, such as nickel, iron, and phosphorus (NiFeP), to form (oxy) hydroxides (OHs), functional carbonaceous structures with a high density of pores and large specific surface areas can be achieved. The resulting materials, designated as NiFeP/NPC OHs, are characterized by their remarkable porosity, high conductivity, large surface area, and chemical stability. These properties make NiFeP/NPC OHs particularly suitable for electrocatalysis, where they exhibit outstanding activity in both HER and OER. The optimized NiFeP/NPC OHs material shows a very low overpotential of 93 mV for HER and 243 mV for OER at 10 mA cm⁻2 and high durability over 100 h. Moreover, the bifunctional NiFeP/NPC OHs electrode demonstrates exceptional catalytic activity and stability in alkaline solutions. This study not only highlights the innovative synthesis of NPC from BPW and the cost-effective fabrication of NiFeP/NPC OHs but also sparks curiosity about the potential of this novel synthesis method.