Microporous Cobalt Ferrite with Bio-Carbon Loosely Decorated to Construct Multi-Functional Composite for Dye Adsorption, Anti-Bacteria and Electromagnetic Protection.

Currently, facing electromagnetic protection requirement under complex aqueous environments, the bacterial reproduction and organic dye corrosion may affect the composition and micro-structures of absorbers to weaken their electromagnetic properties. To address such problems, herein, a series of CoFe2O4@BCNPs (cobalt ferrite @ bio-carbon nanoparticles) composites are synthesized via co-hydrothermal and calcining process. The coupling of magnetic cobalt ferrite and dielectric bio-carbon derived from Apium can endow the composite multiple absorption mechanisms and matched impedance for effective microwave absorption, attaining a bandwidth of 8.12 GHz at 2.36 mm and an intensity of -49.85 dB at 3.0 mm. Due to the ROS (reactive oxygen species) stimulation ability and heavy metal ions of cobalt ferrite, the composite realizes an excellent antibacterial efficiency of 99% against Gram negative bacteria of Escherichia coli. Moreover, the loose porous layer of surface stacked bio-carbon can promote the adsorption of methylene blue for subsequent eliminating, a high removal rate of 90.37% for organic dye can be also achieved. This paper offers a new insight for rational design of composite's component and micro-structure to construct multi-functional microwave absorber for satisfying the electromagnetic protection demand in complicated environments.

Construction of Hierarchical Films via Layer-by-Layer Assembly of Exfoliated Unilamellar Zeolite Nanosheets.

Zeolites have been widely applied as versatile catalysts, sorbents, and ion exchangers with unique porous structures showing molecular sieving capability. In these years, it is reported that some layered zeolites can be delaminated into molecularly thin 2-dimensional (2D) nanosheets characterized by inherent porous structures and highly exposed active sites. In the present study, two types of zeolite nanosheets with distinct porous structures with MWW topology (denoted mww) and ferrierite-related structure (denoted bifer) are deposited on a substrate through the solution process via electrostatic self-assembly. Alternate deposition of zeolite nanosheets with polycation under optimized conditions allows the layer-by-layer growth of their multilayer films with a stacking distance of 2-3 nm. Furthermore, various hierarchical structures defined at the unit-cell dimensions can be constructed simply by conducting the deposition of mww and bifer nanosheets in a designed sequence. Adsorption of a dye, Rhodamine B, in these films, is examined to show that adsorption is dependent on constituent zeolite nanosheets and their assembled nanostructures. This work has provided fundamental advancements in the fabrication of artificial zeolite-related hierarchical structures, which may be extended to other zeolite nanosheets, broadening their functionalities, applications, and benefits.

Hierarchical Porous Aerogels With Multiple Adsorptive Interactions for Dye Wastewater Purification.

Aerogels present a huge potential for removing organic dyes from printing and dyeing wastewater (PDW). However, the preparation of aerogels with multiple dye adsorption capabilities remains a challenge, as many existing aerogels are limited to adsorbing only a single type of dye. Herein, a composite aerogel (CG/T-rGO) with the addition of carboxymethyl chitosan, gelatin and tannic acid reduced graphene oxide (T-rGO) was synthesized by freeze-drying technology. The electrostatic interactions between dye molecular and GEL/CMCS (CG) networks, as well as the supramolecular interactions (H-bonds, electrostatic interactions and π-π stacks) between T-rGO, have endowed the aerogel with the ability to adsorb multiple types of dye, such as methylene blue (MB) and methyl orange (MO). Results exhibited that the prepared CG/T-rGO aerogel possessed strong mechanical strength and a porous 3D network structure with a porosity of 96.33 %. Using MB and MO as adsorbates, the adsorption capacity (88.2 mg/g and 66.6 mg/g, respectively) and the mechanism of the CG/T-rGO aerogel were investigated. The adsorption processes of aerogel for MB and MO were shown to follow the pseudo-second-order kinetic model and Langmuir isotherm model, indicating the chemical adsorption of a monolayer. The proposed aerogel in this work has promising prospects for dye removal from PDW.

Crystal to Hydrogel Transformation in S-Benzyl-L-Cysteine-Containing Cyclic Dipeptides - Nanostructure Elucidation and Applications.

Cyclic dipeptides (CDPs) are crucial building blocks for a range of functional nanomaterials due to their simple chemical structure and high molecular stability. In this investigation, we synthesized a set of S-benzyl-L-cysteine-based CDPs (designated as P1-P6) and thoroughly examined their self-assembly behavior in a methanol-water solvent to elucidate the relationship between their structure and gelation properties. The hydrophobicity of the amino acids within the CDPs was gradually increased. The present study employed a comprehensive array of analytical techniques, including NMR, FT-IR, AFM, thioflavin-T, congo-red CD, X-ray crystallography, and biophysical calculations like Hirshfield Surface analysis and DFT analysis. These methods revealed that in addition to hydrogen bonding, the hydrophobic nature of the amino acid side chain significantly influences the propensity of CDPs to form hydrogels. Each CDP yielded distinct nanofibrillar networks rich in ß-sheet structures, showcasing unique morphological features. Moreover, we explored the practical application of these CDP-based hydrogels in water purification by utilizing them to remove harmful organic dyes from contaminated water. This application underscores the potential of CDPs in addressing environmental challenges, offering a promising avenue for the future development of these materials in water treatment technologies.

In Situ Growth of Nitrogen-Doped Fluorescent Carbon Dots on Sisal Fibers: Investigating Their Selective and Enhanced Adsorption Capabilities for Methyl Blue Dye.

Preparing a biomass adsorbent material with high-absorption performance but low cost plays a vital role in wastewater treatment. In this study, a novel nitrogen-doped sisal fiber-based carbon dots (SF-N-CDs) composite was prepared by directly growing carbon dots (CDs) on sisal fiber (SF) using a microwave method with polyethyleneimine (PEI) as a raw material. The prepared SF-N-CDs were characterized using FTIR, XRD, Contact angle(CA), TGA, XPS, and SEM. The results revealed that the CDs were successfully grown on SF. The adsorption properties of SF-N-CDs were significantly enhanced when they adsorbed methyl blue (MeB) dye. Specifically, the adsorption of MeB by SF-N-CDs was up to 619.7 mg/g, which was about 2.6 times higher than that of raw SF. This implied that the introduction of CDs increases the adsorption site, thus enhancing the adsorption capacity. Analysis on kinetics and thermodynamics of MeB adsorption by SF-N-CDs revealed that the adsorption process followed the Langmuir isotherm model and were consistent with both kinetic models. It signifies that the adsorption involves both physical and chemical adsorption processes. Further, the SF-N-CDs maintained a removal rate of 70.9% after six adsorption-regeneration cycles, demonstrating good regeneration performance. Moreover, the SF-N-CDs could selectively separate MeB from a mixture of rhodamine B and saffron T. Consequently, the findings of this study suggest that SF-N-CDs are promising adsorbents for anionic dyes.

Removal of anionic dye from textile effluent using zirconium phosphate loaded polyaniline-graphene oxide composite: Lab to pilot scale evaluation.

Efficient filtering of dyes is essential for the protection of ecosystem and human health due to the considerable water pollution caused by the effluents released from the sector. We present a simple, scalable UV radiation-assisted method for treating methyl orange dye-polluted water from the textile industry using zirconium phosphate-loaded polyaniline-graphene oxide (PGZrP) composite. The new material was synthesized by sonochemically incorporating a polyaniline-graphene oxide composite with hydrothermally synthesized zirconium phosphate. The efficacy of PGZrP in eliminating methyl orange was evaluated using experimental conditions, and the adsorption capacity was investigated as a function of pH, temperature, adsorbent dosage, and adsorption period. The system follows Langmuir adsorption isotherm with pseudo-second-order kinetics. Thermodynamics studies showed that enthalpy (H°) and entropy (S°) values are positive, indicating that the dye adsorption increases with increasing temperature and is an endothermic reaction. The maximum adsorption capacity was found to be 36.45379 mg/g for methyl orange. Using the COMSOL Multiphysics CFD Platform, an attempt was made to check the temperature and concentration profile of a PGZrP composite in a real industrial system. The predicted result shows that there is no significant temperature change in the material during the adsorption process and the concentration of dye is mainly located on the top region of the bed. The developed zirconium phosphate decorated polyaniline-graphene oxide composite can be successfully utilized for the effective removal of methyl orange from industrial wastewater in bulk quantity which is coming from the textile industry, and the composite can be reused for several cycles with good efficiency. In this work, we have designed a miniaturized proof of concept to remove methyl orange from water which showed good dye removal efficiency.

Synergistic Effect of UiO-66 Directly Grown on Kombucha-Derived Bacterial Cellulose for Dye Removal.

Metal-Organic Frameworks (MOFs) are particularly attractive sorbents with great potential for the removal of toxic dye pollutants from industrial wastewaters. The uniform dispersion of MOF particles on suitable substrates then represents a key condition to improve their processability and provide good accessibility to the active sites. In this work, we investigate the efficiency of a natural bacterial cellulose material derived from Kombucha (KBC) as an active functional support for growing and anchoring MOF particles with UiO-66 structures. An original hierarchical microstructure was obtained for the as-developed Kombucha cellulose/UiO-66 (KBC-UiO) composite material, with small MOF crystals (~100 nm) covering the cellulose fibers. Promising adsorption properties were demonstrated for anionic organic dyes such as fluorescein or bromophenol blue in water at pH 5 and pH 7 (more than 90% and 50% removal efficiency, respectively, after 10 min in static conditions). This performance was attributed to both the high accessibility and uniform dispersion of the MOF nanocrystals on the KBC fibers together with the synergistic effects involving the attractive adsorbing properties of UiO-66 and the surface chemistry of KBC. The results of this study provide a simple and generic approach for the design of bio-sourced adsorbents and filters for pollutants abatement and wastewater treatment.

Supramolecular Gels Based on C3-Symmetric Amides: Application in Anion-Sensing and Removal of Dyes from Water.

We modified C3-symmetric benzene-1,3,5-tris-amide (BTA) by introducing flexible linkers in order to generate an N-centered BTA (N-BTA) molecule. The N-BTA compound formed gels in alcohols and aqueous mixtures of high-polar solvents. Rheological studies showed that the DMSO/water (1:1, v/v) gels were mechanically stronger compared to other gels, and a similar trend was observed for thermal stability. Powder X-ray analysis of the xerogel obtained from various aqueous gels revealed that the packing modes of the gelators in these systems were similar. The stimuli-responsive properties of the N-BTA towards sodium/potassium salts indicated that the gel network collapsed in the presence of more nucleophilic anions such as cyanide, fluoride, and chloride salts at the MGC, but the gel network was intact when in contact with nitrate, sulphate, acetate, bromide, and iodide salts, indicating the anion-responsive properties of N-BTA gels. Anion-induced gel formation was observed for less nucleophilic anions below the MGC of N-BTA. The ability of N-BTA gels to act as an adsorbent for hazardous anionic and cationic dyes in water was evaluated. The results indicated that the ethanolic gels of N-BTA successfully absorbed methylene blue and methyl orange dyes from water. This work demonstrates the potential of the N-BTA gelator to act as a stimuli-responsive material and a promising candidate for water purification.

Renewing Interest in Zeolites as Adsorbents for Capture of Cationic Dyes from Aqueous and Ethanolic Solutions: A Simulation-Based Insight into the Efficiency of Dye Adsorption in View of Wastewater Treatment and Valorization of Post-Sorption Materials.

The impact of solvents on the efficiency of cationic dye adsorption from a solution onto protonated Faujasite-type zeolite (FAU-Y) was investigated in the prospect of supporting potential applications in wastewater treatment or in the preparation of building blocks for optical devices. The adsorption isotherms were experimentally determined for methylene blue (MB) and auramine O (AO) from single-component solutions in water and in ethanol. The limiting dye uptake (saturation capacity) was evaluated for each adsorption system, and it decreased in the order of MB-water > AO-water > AO-ethanol > MB-ethanol. The mutual distances and orientations of the adsorbed dye species, and their interactions with the oxygen sites of the FAU-Y framework, with the solvent molecules, and among themselves were inferred from Monte Carlo simulations and subsequently utilized to rationalize the observed differences in the saturation capacity. The dye-solvent competition and the propensity of the dyes to form compact pi-stacked dimers were shown to play an important role in establishing a non-uniform distribution of the adsorbed species throughout the porous space. The two effects appeared particularly strong in the case of the MB-water system. The necessity of including solvent effects in modeling studies is emphasized.

Structure Characterization and Dye Adsorption Properties of Modified Fiber from Wheat Bran.

The fibers from four wheat varieties (FT, XW 26, XW 45, and KW 1701) were selected and chemically modified with NaOH, epichlorohydrin, and dimethylamine to improve the adsorption capacity for anionic dye. The structure of the fibers with or without modification was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectrometry. The modified products were studied from the aspects of adsorption capacities, adsorption kinetics, and thermodynamics to provide a reference for the utilization of wheat bran. By SEM, more porous and irregular structures were found on the modified fibers. The XRD results showed that the crystals from the original fibers were destroyed in the modification process. The changes in fibers' infrared spectra before and after modification suggested that quaternary ammonium salts were probably formed in the modification process. The maximum adsorption capacity of wheat bran fibers for Congo red within 120 min was 20 mg/g for the unmodified fiber (XW 26) and 93.46 mg/g for the modified one (XW 45). The adsorption kinetics of Congo red by modified wheat bran fiber was in accord with the pseudo-second-order kinetic model at 40 °C, 50 °C, and 60 °C, indicating that the adsorption process might be mainly dominated by chemisorption. The adsorption was more consistent with the Langmuir isothermal adsorption model, implying that this process was monolayer adsorption. The thermodynamic parameters suggested that the adsorption occurred spontaneously, and the temperature increase was favorable to the adsorption. As mentioned above, this study proved that the wheat bran fiber could possess good adsorption capacities for anion dye after chemical modification.

Process Optimization and Equilibrium, Thermodynamic, and Kinetic Modeling of Toxic Congo Red Dye Adsorption from Aqueous Solutions Using a Copper Ferrite Nanocomposite Adsorbent.

In the present investigation of copper ferrite, a CuFe2O4 nanocomposite adsorbent was synthesized using the sol-gel method, and its relevance in the adsorptive elimination of the toxic Congo red (CR) aqueous phase was examined. A variety of structural methods were used to analyze the CuFe2O4 nanocomposite; the as-synthesized nanocomposite had agglomerated clusters with a porous, irregular, rough surface that could be seen using FE-SEM, and it also contained carbon (23.47%), oxygen (44.31%), copper (10.21%), and iron (22.01%) in its elemental composition by weight. Experiments were designed to achieve the most optimized system through the utilization of a central composite design (CCD). The highest uptake of CR dye at equilibrium occurred when the initial pH value was 5.5, the adsorbate concentration was 125 mg/L, and the adsorbent dosage was 3.5 g/L. Kinetic studies were conducted, and they showed that the adsorption process followed a pseudo-second-order (PSO) model (regression coefficient, R2 = 0.9998), suggesting a chemisorption mechanism, and the overall reaction rate was governed by both the film and pore diffusion of adsorbate molecules. The process through which dye molecules were taken up onto the particle surface revealed interactions involving electrostatic forces, hydrogen bonding, and pore filling. According to isotherm studies, the equilibrium data exhibited strong agreement with the Langmuir model (R2 = 0.9989), demonstrating a maximum monolayer adsorption capacity (qmax) of 64.72 mg/g at pH 6 and 302 K. Considering the obtained negative ΔG and positive ΔHads and ΔSads values across all tested temperatures in the thermodynamic investigations, it was confirmed that the adsorption process was characterized as endothermic, spontaneous, and feasible, with an increased level of randomness. The CuFe2O4 adsorbent developed in this study is anticipated to find extensive application in effluent treatment, owing to its excellent reusability and remarkable capability to effectively remove CR in comparison to other adsorbents.

Triangular Heteroporous Covalent Organic Framework via a K-Shaped "Two-in-One" Monomer: Targeted Synthesis and Selective Removal of Organic Pollutants.

Covalent organic frameworks (COFs) have attracted increasing research interest due to their intriguing topological structures and fascinating properties. Diverse COFs with different shapes and sizes are developed by the design of appropriate building blocks. However, the heteroporous COFs to date are still in their infancy due to the relatively limited configuration of precursors. Herein, it is ingeniously designed and synthesized a new K-shaped "two-in-one" building unit (3',6'-bis(4-(5,5-dimethyl-1,3-dixoan-2-yl)phenyl)-[1,1':2',1"-terphenyl]-4,4"-diamine, BPTD), thus realizing the construction of triangular dual microporous COF (BPTD-COF) via self-polycondensation of the K-shaped monomer. The super micropore (0.76 nm) of BPTD-COF endows the higher density of amine activity sites, while the other aperture size (1.35 nm) meets the need for accommodating cationic dyes (rhodamine B, methylene blue), thus BPTD-COF displays a distinctive selective adsorption for cationic dyes with good reusability.

Efficient removal of organic dyes using electrospun nanofibers with Ce-based UiO-66 MOFs.

Cerium-based UiO-66 (Ce-UiO-66) metal-organic frameworks (MOFs) were synthesized via a facile solvothermal method and fully characterized using FTIR, XRD, BET, SEM, EDX, and zeta potential techniques. The synthesized Ce-UiO-66 particles were embedded into an electrospun cross-linked polyvinyl alcohol (PVA)/chitosan (CTS) nanofiber (EPCNF), and then employed to remove organic dyes from water. The adsorption results demonstrated that the adsorption capacities of both anionic (Congo Red (CR), Methyl Orange (MO) and Methyl Red (MR)) and cationic (Methylene Blue (MB)) dyes over the fabricated electrospun nanofibers (ENFs) increased with increasing the loadings of Ce-UiO-66 MOFs. Accordingly, the adsorption performance of EPCNF-10 (containing 10 wt% of Ce-UiO-66 MOFs) adsorbent toward these organic dyes is in the order of CR (102.04 mg/g) > MO (87.71 mg/g) > MR (65.35 mg/g) > MB (34.24 mg/g). Moreover, it was found that the Freundlich isotherm model and the pseudo-second-order kinetic model were appropriate for describing the adsorption behaviors of EPCNF-10 adsorbent toward both anionic and cationic dyes. Thus, it can be proposed that the fabricated EPCNF-10 adsorbent would be effective adsorbent materials for the removal of anionic and cationic dyes from water due to its excellent adsorption performance, facile preparation, good regeneration, and simple separation from aqueous solutions.

Reusable flexible poly(vinyl alcohol)/chitosan-based polymer carbon dots composite film for acid blue 93 dye adsorption.

The design and synthesis of water-insoluble chitosan-based polymer carbon dots [P(CS-g-CA)CDs] are described. A polyvinyl alcohol/chitosan-based polymer carbon dot [PVA/P(CS-g-CA)CDs] composite film was prepared using a simple casting method to be used in dye adsorption. The composite film was characterized using FT-IR, XPS, transparency, contact angle, and mechanical properties tests, which showed the successful incorporation of P(CS-g-CA)CDs into the film and also revealed that hydrogen bonding improved the mechanical properties of the PVA film. Furthermore, the composite film displayed substantially enhanced hydrophobicity, making it suitable for use in aqueous environments. In addition, the composite film exhibited stable adsorption of acid blue 93 (AB93) at pH 2-9, with an enhanced adsorption capacity of 433.24 mg/g. The adsorption obeyed Langmuir law with an efficiency of more than 89% even after five cycles. Therefore, the PVA/P(CS-g-CA)CDs film is a promising material for the treatment of organic dye-polluted wastewater.

Chitosan-Silica Composites for Adsorption Application in the Treatment of Water and Wastewater from Anionic Dyes.

A series of new types of composites (biopolymer-silica materials) are proposed as selective and effective adsorbents. A new procedure for the synthesis of chitosan-nanosilica composites (ChNS) and chitosan-silica gel composites (ChSG) using geometrical modification of silica and mechanosorption of chitosan is applied. The highest adsorption efficiency was achieved at pH = 2, hence the desirability of modifications aimed at stabilizing chitosan in such conditions. The amount of chitosan in the synthesis grew to 1.8 times the adsorption capacity for the nanosilica-supported materials and 1.6 times for the silica gel-based composites. The adsorption kinetics of anionic dyes (acid red AR88) was faster for ChNS than for ChSG, which results from a silica-type effect. The various structural, textural, and physicochemical aspects of the chitosan-silica adsorbents were analyzed via small-angle X-ray scattering, scanning electron microscopy, low-temperature gas (nitrogen) adsorption, and potentiometric titration, as well as their adsorption effectiveness towards selected dyes. This indicates the synergistic effect of the presence of dye-binding groups of the chitosan component, and the developed interfacial surface of the silica component in composites.

Complete Desorption of Hybrid Nanoclays Composed of Hydrotalcite and Disperse Dye.

Clays are considered great nanoadsorbents for many materials, including textile dyes. The use of these materials for cleaning textile wastewater is well known; however, it is not at all common to find applications for the hybrid materials formed from the clay and dye. In this work, a dye-loaded clay material was used to make new dye baths and colour a polyester textile substrate. The same hybrid could be used several times as it did not use all the adsorbed dye in a single dyeing. The hybrid obtained from hydrotalcite (nanoclay) and the dispersed red 1 dye was analysed by measuring the colour obtained, carrying out an X-ray diffraction analysis that provided information after each desorption-dyeing process, and using infrared spectroscopy to analyse the specific bands of each characteristic group. Both analyses showed that the amount of dye present in the hybrid decreases. Thermogravimetry (TGA), surface area and porosity measurements (BET), and X-ray photoelectron spectroscopy (XPS) tests were conducted. Chemical stability was assessed by subjecting the hybrid to the actions of different reagents. In addition, colour fastness tests were carried out after dyeing and washing the polyester test tubes to check for the correct fixing of the dye to the fibre. These fastness results showed that the dyeing was carried out correctly and as if it was a conventional dyeing process.

Dyeing with Hydrotalcite Hybrid Nanoclays and Disperse, Basic and Direct Dyes.

Textile effluents are among the most polluting industrial effluents in the world. Textile finishing processes, especially dyeing, discharge large quantities of waste that is difficult to treat, such as dyes. By recovering this material from the water, in addition to cleaning and the possibility of reusing the water, there is the opportunity to reuse this waste as a raw material for dyeing different textile substrates. One of the lines of reuse is the use of hybrid nanoclays obtained from the adsorption of dyes, which allow dye baths to be made for textile substrates. This study analyses how, through the use of the nanoadsorbent hydrotalcite, dyes classified by their charge as anionic, cationic and non-ionic can be adsorbed and recovered for successful reuse in new dye baths. The obtained hybrids were characterised by X-ray diffraction and infrared spectroscopy. In addition, the colour was analysed by spectrophotometer in the UV-VIS range. The dyes made on cotton, polyester and acrylic fabrics are subjected to different colour degradation tests to assess their viability as final products, using reflection spectroscopy to measure the colour attribute before and after the tests, showing results consistent with those of a conventional dye.

κ-Carrageenan/triazin-based covalent organic framework bionanocomposite: Preparation, characterization, and its application in fast removing of BB41 dye from aqueous solution.

A novel and high efficient adsorbent was prepared based on an environmentally friendly substrate, κ-carrageenan, and a triazine-based covalent organic framework as a co-adsorbent component. Combining these two precursors leads to an effective nanocomposite for removing Basic blue 41 dye from aqueous media. After confirm the structural of prepared composite by various analysis, the adsorption properties were investigated. The optimum conditions were obtained in: pH: 7, temperature: 25 °C and contact time: 210 min; and adsorbent dosage of 10 mg. According to the isotherms study, the basic blue 41 dye adsorption was matched to the Longmuir model with single-layer mechanism. The kinetic of adsorption was studied and fitted with pseudo-second order model with R2 = 0.971. From the results the maximum adsorption capacity of 833 mg/g was obtained in 15 min and the reusability tests showed 24% decrease in yield after three cycles.

In Situ Electrospun Porous MIL-88A/PAN Nanofibrous Membranes for Efficient Removal of Organic Dyes.

In recent years, metal-organic framework (MOF)-based nanofibrous membranes (NFMs) have received extensive attention in the application of water treatment. Hence, it is of great significance to realize a simple and efficient preparation strategy of MOF-based porous NFMs. Herein, we developed a direct in situ formation of MOF/polymer NFMs using an electrospinning method. The porous MOF/polymer NFMs were constructed by interconnecting mesopores in electrospun composite nanofibers using poly(vinylpolypyrrolidone) (PVP) as the sacrificial pore-forming agent. MOF (MIL-88A) particles were formed inside the polyacrylonitrile (PAN)/PVP nanofibers in situ during electrospinning, and the porous MIL-88A/PAN (pMIL-88A/PAN) NFM was obtained after removing PVP by ethanol and water washing. The MOF particles were uniformly distributed throughout the pMIL-88A/PAN NFM, showing a good porous micro-nano morphological structure of the NFM with a surface area of 143.21 m2 g-1, which is conducive to its efficient application in dye adsorption and removal. Specifically, the dye removal efficiencies of the pMIL-88A/PAN NFM for amaranth red, rhodamine B, and acid blue were as high as 99.2, 94.4, and 99.8%, respectively. In addition, the NFM still showed over 80% dye removal efficiencies after five adsorption cycles. The pMIL-88A/PAN NFM also presented high adsorption capacities, fast adsorption kinetics, and high cycling stabilities during the processes of dye adsorption and removal. Overall, this work demonstrates that the in situ electrospun porous MOF/polymer NFMs present promising application potential in water treatment for organic dyestuff removal.

Effective Removal of Dyes from Wastewater by Osmanthus Fragrans Biomass Charcoal.

The exploration of low-cost, high-performance adsorbents is a popular research issue. In this work, a straightforward method that combined hydrothermal with tube firing was used to produce Osmanthus fragrans biomass charcoal (OBC) from low-cost osmanthus for dye adsorption in water. The study examined the parameters of starting concentration, pH, and duration, which impacted the process of adsorption of different dyes by OBC. The analysis showed that the adsorption capacities of OBC for six dyes: malachite green (MG, C0 = 800 mg/L, pH = 7), Congo red (CR, C0 = 1000 mg/L, pH = 8), rhodamine B (RhB, C0 = 500 mg/L, pH = 6), methyl orange (MO, C0 = 1000 mg/L, pH = 7), methylene blue (MB, C0 = 700 mg/L, pH = 8), and crystalline violet (CV, C0 = 500 mg/L, pH = 7) were 6501.09, 2870.30, 554.93, 6277.72, 626.50, and 3539.34 mg/g, respectively. The pseudo-second-order model and the Langmuir isotherm model were compatible with the experimental findings, which suggested the dominance of ion exchange and chemisorption. The materials were characterized by using XRD, SEM, FTIR, BET, and XPS, and the results showed that OBC had an outstanding specific surface area (2063 m2·g-1), with potential adsorption mechanisms that included electrostatic mechanisms, hydrogen bonding, and π-π adsorption. The fact that the adsorption capacity did not drastically decrease after five cycles of adsorption and desorption suggests that OBC has the potential to be a dye adsorbent.