Functionalization of SBA-15 with TCPP for pollutant removal: Structural characterization and adsorption performance

Synthesis of Mg–Al layered double hydroxides-functionalized hydrochar composite via an in situ one-pot hydrothermal method for arsenate and phosphate removal: Structural characterization and adsorption performance

The removal of dye and toxic ionic pollutants from water is an extremely important issue. A simple filtration process to decontaminate water by employing a free‐standing fibrous membrane fabricated from highly uniform carbonaceous nanofibers (CNFs) is demonstrated. This process combines the excellent adsorption behavior of CNFs and the advantages of membrane filtration over conventional adsorption techniques, which include simple scale‐up, reduced time, and lower energy consumption. Batch adsorption experiments showed that the CNFs exhibited larger adsorption capacities than commercial granular active carbon (GAC) and carbon nanotubes (CNTs) because of their large surface area, high uniformity, and numerous active sites on the surface of nanofibers. Membrane filtration experiments proved that the CNF membranes could remove methylene blue (MB) efficiently at a very high flux of 1580 L m−2 h−1, which is 10–100 times higher than that of commercial nano‐ or ultrafiltration membranes with similar rejection properties. The high permeability of CNF membrane permits stacking of membranes to improve adsorption capacity. In addition, the CNF membranes are easily regenerated and remain unaltered in adsorption performance over six successive cycles of dye adsorption, desorption, and washing. Given the high adsorption and regenerability performance of the CNF membrane, it should have potential applications in water purification.

The increasing discharge of dye pollutants, particularly methylene blue (MB), into aquatic systems represents a critical environmental challenge due to their persistence, toxicity, and resistance to biodegradation. In this study, we report the synthesis and characterization of a novel flexible adsorbent film composed of tetraformyl calix[4]arene, polyvinyl chloride (PVC), multi-walled carbon nanotubes (MWCNTs), and graphite (TfCPMG). The calixarene moieties introduce highly active formyl functionalities and aromatic cavities, enabling strong electrostatic and π-π interactions with cationic dyes, while the MWCNT and graphite components provide structural reinforcement, conductivity, and additional adsorption sites. Structural characterization using FT-IR, Raman, BET, and FE-SEM confirmed the successful integration of these components and revealed a heterogeneous, porous surface favorable for adsorption. Adsorption performance was systematically evaluated by examining the effects of pH, adsorbent dosage, contact time, and initial MB concentration. The TfCPMG film exhibited an optimal removal efficiency of 80% for a 5 ppm MB solution at pH 9, with rapid kinetics reaching equilibrium within 10min. Notably, the adsorbent maintained > 78.5% removal efficiency after ten adsorption-desorption cycles, demonstrating excellent reusability and stability. Comparative analysis against previously reported adsorbents highlights the superior efficiency, low cost, and operational simplicity of the fabricated film. These findings establish the TfCPMG flexible film as a high-performance, scalable, and sustainable adsorbent, offering a promising solution for practical wastewater treatment and dye pollution remediation.

Porous metal-organic framework-acrylamide-chitosan composite aerogels: Preparation, characterization and adsorption mechanism of azo anionic dyes adsorbed from water

A novel modified lignin-based adsorbent for removal of malachite green and Pb2+ ions from wastewater

Fabrication of the novel hydrogel based on waste corn stalk for removal of methylene blue dye from aqueous solution

This study evaluates copper(II) ion removal using biochar synthesized from Acacia auriculiformis wood waste, an unmodified and locally abundant biomass. Batch, column, kinetic, thermodynamic, and regeneration studies were integrated to provide a systematic assessment of adsorption behavior. Batch experiments achieved a maximum copper removal efficiency of 97.08% at a biochar dosage of 0.5 g, with equilibrium attained within 240 min and a Langmuir-modeled adsorption capacity of 98.15 mg/g (R2 = 0.9862). Kinetic analysis indicated that chemisorption played a dominant role, as supported by the pseudo-second-order model (R2 = 0.9993; rate constant = 0.0036 g·mg⁻1·min⁻1). Thermodynamic parameters revealed a spontaneous and endothermic adsorption process (ΔG° = − 3.74 kJ/mol; ΔH° = 25.76 kJ/mol; ΔS° = 94.31 J·mol⁻1·K⁻1). Column studies conducted under varying flow rates (0.5–1.5 mL/min), bed depths (5–15 cm), and influent copper concentrations (50–250 mg/L) exhibited consistent adsorption capacities (48–50 mg/g) and breakthrough times ranging from 300 to 1140 min. Regeneration experiments demonstrated initial desorption and reuse efficiencies of 81.82% and 67.94%, respectively; however, adsorption performance declined over three successive cycles due to pore structure degradation and depletion of surface functional groups. Structural and chemical characterization using SEM, BET, FTIR, and EDAX indicated surface deterioration and residual copper retention after regeneration. Overall, A. auriculiformis biochar exhibits competitive adsorption performance compared with other lignocellulosic biochars, suggesting its potential as a low-cost and eco-friendly option for copper removal in water treatment applications.

Orderly Porous Covalent Organic Frameworks-based Materials: Superior Adsorbents for Pollutants Removal from Aqueous Solutions

Widespread environmental pollution caused by the misuse of tetracyclines (TCs) has become a global issue, necessitating the development of water treatment materials for antibiotic removal. Magnetic biochar (MBC) possesses several advantages, including a wide range of raw material sources and low cost, making it a potential adsorbent that overcomes the limitations of biochar (BC) regarding solid–liquid separation. In this study, peanut shell-derived magnetic biochar loaded with Fe3O4 (Fe3O4/BC) was prepared to study its adsorption performance and environmental factors for TCs. The adsorption mechanism was revealed using adsorption isotherms, adsorption kinetics and thermodynamics. The results showed that the total pore volume was increased, and surface oxygen-containing functional groups were formed of that before BC modification. In a wide pH range, Fe3O4/BC showed high adsorption performance for TCs, with an adsorption rate of over 85%. Chemical adsorption was the main adsorption mechanism, including hydrogen bonding, as well as π-π interactions, electrostatic interactions, intrapore diffusion and hydrophobic interactions. Moreover, reusability and obtaining cost of the material were analyzed, demonstrating its promising application prospects. This study will promote the application of Fe3O4/BC in the removal of antibiotics pollutants from water.

Experimental and simulation study on structural characterization and hydrogen storage of metal organic structured compounds

Hierarchically porous graphene-like biochar for efficient removal of aromatic pollutants and their structure-performance relationship: A combined experimental, MD and DFT study

In this study, cerium-based metal–organic frameworks (MOFs), cerium terephthalate (CeTPA), were synthesized and incorporated into nanofibers via electrospinning using poly(methyl methacrylate) (PMMA). The synthesized materials were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and Tauc plot analysis. The electrospun CeTPA nanofibers exhibited superhydrophobic properties, with water contact angles exceeding 150°. The adsorption and catalytic performance of the nanofibers were assessed for dye removal using Congo red (CR) and methylene blue (MB) as model organic pollutants. Adsorption studies demonstrated negligible dye uptake due to the hydrophobicity of the fibers, while catalytic degradation experiments in the presence of hydrogen peroxide (H2O2) showed significant degradation of CR but limited effectiveness against MB, offering high selectivity toward anionic dyes. Structural and optical characterizations confirmed the stability and catalytic activity of CeTPA nanofibers, highlighting their potential for selective dye degradation in wastewater treatment applications.

Modification is widely used to enhance the adsorption performance of pristine hydrochar (HBC) and pyrochar (BC). However, comparisons between modified HBC and BC toward pollutant removal have rarely been reported. In this study, pristine HBC and BC derived from rice straw were first produced, and then citric acid (CA) was used as a modifier to synthesize CA-modified HBC (CAHBC) and CA-modified BC (CABC). Furthermore, the adsorption performance of biochars toward methylene blue (MB) was investigated. The results showed that BC exhibits relatively rough surfaces and contains more minerals (ash), whereas HBC has plentiful O-containing functional groups and fewer minerals. CA modification partially removed minerals from the surface of BC, which weakened the ion exchange, surface complexation, and n-π interaction, resulting in a lower adsorption ability toward MB. By contrast, CA produced more O-containing functional groups on the surface of HBC, which strengthened the hydrogen bonding and electrostatic interaction, thus increasing the adsorption capacity toward MB. The two-compartment model showed a good fit to the adsorption process of MB on CAHBC, and the isotherm data for MB adsorption by HBC and CAHBC are suitable for the Freundlich model. The highest adsorption amount of MB using CAHBC was 80.13mg·g-1, which was 27.66% higher than that for CABC. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis indicated that the carboxyl groups in the surface functional groups of CAHBC played a crucial role in the MB adsorption process. In addition, CAHBC showed a good performance for a wide range of pH values (4.0-10.0) and under the interference of coexisting ions, and also presented a recycling ability. Furthermore, the adsorption of MB on CAHBC biochar was a spontaneous, exothermic, degree-of-randomness-increasing process. Consequently, CA modification of HBC is a promising strategy and could be used for MB removal from aquatic environments.

Water supply sludge-based ceramsite denitrification filter: Pollutant removal and microbial community characteristics

Superior removal of inorganic and organic arsenic pollutants from water with MIL-88A(Fe) decorated on cotton fibers