A study on adsorption behavior of newly synthesized banana pseudo-stem derived superabsorbent hydrogels for cationic and anionic dye removal from effluents

Applicability of Ni@ZnO polymer nanocomposite as an adsorbent for removal of methylene blue dye from synthetic wastewater: Batch studies and multilinear regression (MLR) modeling

Synthetic organic dye such as methylene blue (MB) is non-biodegradable and highly toxic, released from textile wastewater. This work investigates the applicability of Ni@ZnO polymer nanocomposite for MB removal from the wastewater. To understand their differences before and after MB adsorption, composites' surface morphology was characterized by various techniques including scanning electron microscope (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Fourier transformation infrared (FT-IR) and UV-Vis spectrophotometer. The adsorption mechanism of target pollutants by the composites was also studied based on isotherm and kinetic models. The correlation between the optimized conditions and the percentage removal was further studied by applying multi linear regression (MLR) model. At the same concentration of 100 mg/L, it was found that under optimized conditions of 1 g/L of adsorbent, pH 7.5, and 190 min of reaction time, about 94% and 98% of MB removal were attained, respectively. In spite of the promising results, treated effluents were still unable to meet the required discharge standards of less than 1 mg/L mandated by local legislation. Furthermore, the MB adsorption by the composite was based on attractive electrostatic interactions. Overall, this study not only provides insights into the adsorption efficiency, but also evaluates the recyclability and stability of the adsorbent, addressing key challenges in practical wastewater treatment. By integrating its novel aspects, this work contributes to a more nuanced understanding of the Ni@ZnO composite's potential in environmental applications, distinguishing this work from existing literature on MB adsorption.

Environmental and Wastewater Treatment Applications of Stimulus-Responsive Hydrogels

Stimulus-responsive hydrogels have emerged as versatile materials for environmental and wastewater treatment applications due to their ability to adapt to changing environmental conditions. This review highlights recent advances in the design, synthesis, and functionalization of such hydrogels, focusing on their environmental applications. Various synthesis techniques, including radical polymerization, grafting, and copolymerization, enable the development of hydrogels with tailored properties such as enhanced adsorption capacity, selectivity, and reusability. The incorporation of nanoparticles and bio-based polymers further improves their structural integrity and pollutant removal efficiency. Key mechanisms such as adsorption, ion exchange, and photodegradation are discussed, emphasizing their roles in removing heavy metals, dyes, and organic pollutants from wastewater. Additionally, this review presents the potential of hydrogels for oil-water separation, pathogen control, and future sustainability through integration into circular economy frameworks. The adaptability, cost-effectiveness, and eco-friendliness of these hydrogels make them promising candidates for large-scale environmental remediation.

Amide modified cellulose-g-poly acrylic acid as a supple superabsorbent for water retention and soil conditioner

Acrylamide has high hydrophilic properties due to the presence of hydrophilic amide functional groups and is frequently used to synthesize superabsorbents. However, the toxic and carcinogenic properties of acrylamide have caused environmental concerns. The main goal of this paper is the synthesis of superabsorbent with high water absorption from biodegradable and biocompatible cellulose polymer containing amide groups in the backbone of it instead of grafting harmful acrylamide monomers to cellulose. The supple superabsorbent of amide-2,4 modified cellulose-g-poly acrylic acid (Am-2,4 modified cellulose-g-poly (AA)) to reduce water consumption in agriculture and facilitate rooting and root penetration in clay was used. To investigate the effectiveness of superabsorbent in agriculture, its water retention in treated soil (0.2 %) with different temperatures, pHs, and soil textures (sandy loam (SL), sandy clay loam (SCL), clay loam (CL), and loam (L)) was studied. Also, water retention in SCL soil in 2 cycles showed good results. Furthermore, the study includes the optimization of the parameters affecting the water absorption capacity of the superabsorbent, which leads to the absorption of 1253.20 ± 49.67 g/g in distilled water, 86.88 ± 13.36 g/g in 1.0 wt% NaCl solution, and 395 ± 14.86 g/g in tap water under optimal conditions.

Rapid and efficient removal of water-soluble dyes via natural asphalt oxide as a new carbonaceous super adsorbent; NA-oxide synthesis and characterization

In this study, natural asphalt was oxidized to synthesize a new nano-structure adsorbent for dye removal. The functionalization of natural asphalt by oxidation introduced new properties that influenced its activity. The process of oxidizing natural asphalt with potassium permanganate resulted in a low-cost adsorbent, which can potentially be a more affordable option compared with synthetic alternatives. Characterization analysis confirmed the enhanced surface area, improving dye interaction and adsorption. The interconnected channels and capillaries of the oxidized natural asphalt facilitated the capillary action drawing in liquids, including dyes. The distinctive porosity of natural asphalt oxide (NA-oxide) was noted, and the experimental results showed that the NA-oxide nanoadsorbent efficiently adsorbed cationic and anionic dyes in water, with maximum capacities of 14.68 mg.g-1, 17.81 mg.g-1 and 16.47 mg.g-1 for methyl orange, methylene blue and Rhodamine B, respectively. The study investigated various parameters, such as concentration, adsorption dose, pH, contact time, and temperature, affecting the dye removal process. Langmuir, Freundlich, and Temkin isotherms along with pseudo-first and pseudo-second-order kinetic equations were applied to assess the adsorption process, indicating that dyes adhered to the pseudo-first-order model and Langmuir isotherm. Analysis of MO, MB, and RhB dyes revealed conformity to Langmuir isotherm and first-order kinetics. Thermodynamic evaluations like ΔH°, ΔS°, and ∆G° displayed the exothermic and spontaneous nature of dye adsorption on the NA-oxide adsorbent. Furthermore, the absorbent displayed remarkable stability with a recovery rate of 98.45% after ten cycles, signifying its potential for enduring effectiveness in dye removal processes.

Adsorption of methyl orange and methylene blue from aqueous solutions on pure bentonite: statistical physical modeling provides an analytical interpretation

This study investigates the adsorption of methylene blue (MB) and methyl orange (MO) dyes from aqueous solutions using purified Moroccan bentonite, being mainly composed of silica and alumina, in the form of quartz and cristobalite. The temperature controls the adsorption capacity for the kinetics, increasing 5.08% (from 295.1 to 310.1 mg/g) for the MB and 55.47% (from 86.8 to 134.9 mg/g) for the MO. It was discovered that the pseudo-second-order model, with a low Bayesian criterion indicator of 12.72 and R2adj > 0.996, was the best suitable for explaining both systems. The adsorption isotherm, experimental data indicate that both systems follow the Langmuir isotherm. At lower temperatures, 298.15 K 1.22 molecules are adsorbed per site. However, at a higher temperature of 328.15 K, the number of molecules is less than a unit of 0.68. As for MO, the number of molecules remains above 1.4 per site for all the temperatures studied. The endothermic nature of the system is indicated by the observation that the adsorption energy tends to grow for both systems: for the MB, it increases from 18.85 to 21.26 kJ/mol, and for the MO, it increases from 14.83 to 19.01 kJ/mol. Last, thermodynamic functions indicate that maximum entropy is reached around the half-concentration saturation at 25 and 124 mg/L, which is the maximum energetic concentration of the system. The same results were obtained for Gibbs free energy, where the maximum energy found was - 5.39 × 10-18 kJ/mol for the MB and - 1.99 × 10-18 kJ/mol for the MO at 328.15 K.

Development of banana pseudo stem cellulose fiber based magnetic nanocomposite as an adsorbent for dye removal

A hybrid hydrogel nanocomposite derived from cellulose fiber extracted from Banana Pseudo Stem (BPS) was developed as an adsorbent material for wastewater treatment. The hydrogel was developed by graft copolymerization of N-hydroxyethylacrylamide on Cellulose Fiber (BPSCF-g-PHEAAm) with potassium peroxodisulphate (KPS) as an initiator and N, N'-methylene bisacrylamide (MBA) as a crosslinker using microwave irradiation. Magnetic nanoparticles generated by an in-situ method were incorporated into the network structure. Fourier Transform Infrared Spectroscopy (FTIR), Powder X-ray Diffraction (XRD), Thermogravimetric analysis (TGA), Vibrating Sample Magnetometer (VSM), Brunauer-Emmett-Teller analysis (BET), Field Emission Scanning Electron Microscopy (FESEM), and Energy Dispersive Spectrometer (EDS) were employed. The adsorption capacities of hydrogel and its nanocomposite were evaluated using Methylene Blue (MB) and Crystal Violet (CV) as model dyes. The parent gel exhibited the maximum absorption capacity of 235, and 219 mg g-1 towards MB and CV respectively which was enhanced to 320 and 303 mg g-1 for the nanocomposite. Adsorption data were best fitted with the pseudo-second-order kinetic model and the Freundlich isotherm model. Negative ΔG° and positive ΔH° indicated spontaneous and endothermic adsorption. Desorption was effective to an extent of 99 % in the HCl medium suggesting high reusability potential of the developed adsorbent material.

Revolutionizing wastewater treatment: A review on the role of advanced functional bio-based hydrogels

Water contamination poses a significant challenge to environmental and public health, necessitating sustainable wastewater treatment solutions. Adsorption is one of the most widely used techniques for purifying water, as it effectively removes contaminants by transferring them from the liquid phase to a solid surface. Bio-based hydrogel adsorbents are gaining popularity in wastewater treatment due to their versatility in fabrication and modification methods, which include blending, grafting, and crosslinking. Owning to their unique structure and large surface area, modified hydrogels containing reactive groups like amino, hydroxyl, and carboxyl, or functionalized hydrogels with inorganic nanoparticles particularly graphene nanomaterials, have demonstrated promising adsorption capabilities for both inorganic and organic contaminants. Bio-based hydrogels have excellent physicochemical properties and are non-toxic, environmentally friendly, and biodegradable, making them extremely effective at removing contaminants like heavy metal ions, dyes, pharmaceutical pollutants, and organic micropollutants. The versatility of hydrogels allows for various forms to be used, such as films, beads, and nanocomposites, providing flexibility in handling different contaminants like dyes, radionuclides, and heavy metals. Additionally, researchers also have shown the potential for recycling and regenerating post-treatment hydrogels. This approach not only addresses the challenges of wastewater treatment but also offers sustainable and effective solutions for mitigating water pollution.

Synthesis of carboxymethyl starch co (polyacrylamide/ polyacrylic acid) hydrogel for removing methylene blue dye from aqueous solution

Natural polysaccharides, notably starch, have garnered attention for their accessibility, cost-effectiveness, and biodegradability. Modifying starch to carboxymethyl starch enhances its solubility, swelling capacity, and adsorption efficiency. This research examines the synthesis of an effective hydrogel adsorbent based on carboxymethyl starch for the elimination of methylene blue from aqueous solutions. The hydrogel was synthesized using polyacrylamide and polyacrylic acid as monomers, ammonium persulfate as the initiator, and N,N'-methylenebisacrylamide as the cross-linker. Through FESEM, swelling morphology was evaluated in both distilled water and methylene blue dye. The adsorption data elucidated that the adsorption capacity of the hydrogel significantly depends on the dosage of the adsorbent, pH, and concentration of the MB dye. At a pH of 7 and a dye concentration of 250 mg/L, the hydrogel exhibited an impressive 95 % removal rate for methylene blue. The results indicate that the adsorption process follows pseudo-second-order kinetics and conforms well to the Langmuir adsorption isotherm, indicating a maximum adsorption capacity of 1700 mg/g. According to the pseudo-second-order kinetic model and FTIR analysis, methylene blue chemisorbs to the adsorbent material. Hydrogel absorbents regulate adsorption through both intra-particle diffusion and liquid film diffusion. These results highlight the potential of the new hydrogel absorber for water purification.

Design and preparation of reticular superabsorbent hydrogel material with nutrient slow-release and high shear strength for ecological remediation of abandoned mines with steep slopes

In order to solve ecological remediation issues for abandoned mines with steep slopes, a kind of hydrogels with high cohesion and water-retaining were designed by inorganic mineral skeleton combining with polymeric organic network cavities. This eco-friendly hydrogel (MFA/HA-g-p(AA-co-AM)) was prepared with acrylic acid (AA)-acrylamide (AM) as network, which was grafted with humic acids (HA) as network binding point reinforcement skeleton and polar functional group donors, KOH-modified fly ash (MFA) as internal supporter. The maximum water absorption capacities were 1960 g/g for distilled water, which followed the pseudo-second-order model. This super water absorption was attributed to the first stage of 62 % fast absorption due to the high specific surface area, pore volume and low osmotic pressure, moreover, the multiple hydrophilic functional groups and network structure swell contributed to 36 % of the second stage slow adsorption. In addition, the pore filling of water in mesoporous channels contributed the additional 2 % water retention on the third stage. The high saline-alkali resistance correlated with the electrostatic attraction with MFA and multiple interactions with oxygen-containing functional groups in organic components. MFA and HA also enhanced the shear strength and fertility retention properties. After 5 cycles of natural dehydration and reabsorption process, these excellent characteristics of reusability and water absorption capacity kept above 97 %. The application of 0.6 wt% MFA/HA-g-p(AA-co-AM) at 15° slope could improve the growth of ryegrass by approximately 45 %. This study provides an efficient and economic superabsorbent material for ecological restoration of abandoned mines with steep slopes.

Optimization of hydrothermal synthesis conditions of Bidens pilosa-derived NiFe2O4@AC for dye adsorption using response surface methodology and Box-Behnken design

The presence of stable and hazardous organic dyes in industrial effluents poses significant risks to both public health and the environment. Activated carbons and biochars are widely used adsorbents for removal of these pollutants, but they often have several disadvantages such as poor recoverability and inseparability from water in the post-adsorption process. Incorporating a magnetic component into activated carbons can address these drawbacks. This study aims to optimizing the production of NiFe2O4-loaded activated carbon (NiFe2O4@AC) derived from a Bidens pilosa biomass source through a hydrothermal method for the adsorption of Rhodamine B (RhB), methyl orange (MO), and methyl red (MR) dyes. Response surface methodology (RSM) and Box-Behnken design (BBD) were applied to analyze the key synthesis factors such as NiFe2O4 loading percentage (10-50%), hydrothermal temperature (120-180 °C), and reaction time (6-18 h). The optimized condition was found at a NiFe2O4 loading of 19.93%, a temperature of 135.55 °C, and a reaction time of 16.54 h. The optimum NiFe2O4@AC demonstrated excellent sorption efficiencies of higher than 92.98-97.10% against all three dyes. This adsorbent was characterized, exhibiting a well-developed porous structure with a high surface area of 973.5 m2 g-1. Kinetic and isotherm were studied with the best fit of pseudo-second-order, and Freundlich or Temkin. Qmax values were determined to be 204.07, 266.16, and 177.70 mg g-1 for RhB, MO, and MR, respectively. By selecting HCl as an elution, NiFe2O4@AC could be efficiently reused for at least 4 cycles. Thus, the Bidens pilosa-derived NiFe2O4@AC can be a promising material for effective and recyclable removal of dye pollutants from wastewater.

Fabrication and characterization of tamarind seed gum based novel hydrogel for the targeted delivery of omeprazole magnesium

The tamarind seed gum based novel hydrogel was fabricated by varying concentration of polymer, monomer and crosslinker for the targeted delivery of omeprazole magnesium at stomach pH of 1.5. The free radical graft copolymerization of 2-acrylamido-2-methyl propane sulfonic acid with tamarind seed gum backbone resulted in hydrogel. The formation of sulfonic acid pendant groups in hydrogel was observed by the existence of an infrared absorption band at 1152 cm-1 for SO group. The conversion to semicrystalline nature on incorporation of drug evidenced by powder X-ray diffraction studies with peaks at 2θ = 20.4° 31.5° and 52.2°. The scanning electron microscopy images showed bigger voids which narrowed down for drug loaded matrix, supported by the presence of a peak for magnesium in the energy dispersive X-ray spectroscopy. The greatest swelling was observed at pH 7 with second-order rate constant 1.5371 (g/g)/min and drug release was found to be 97.85 ± 1 % over 1200 min at pH 1.5. The drug release transport was found combination of diffusion and erosion of polymer chain to be super case II diffusion and Hill equation model was good fit. The hydrogel drug conjugate found to be non-toxic at tested concentrations (17 mg/50 mg) on in-vivo testing in Drosophila model.

Efficacious adsorption of divalent nickel ions over sodium alginate-g-poly(acrylamide)/hydrolyzed Luffa cylindrica-CoFe2O4 bionanocomposite hydrogel

Existing Ni2+ heavy metal ions in an aqueous medium are highly hazardous for living organisms and humans. Therefore, designing low-cost adsorbents with enhanced effectiveness is essential for removing nickel ions to safeguard public health. In this study, a novel green nanocomposite hydrogel was synthesized through the free radical solution and bulk polymerization method, and its capability to remove divalent nickel ions from aqueous media was examined. The bionanocomposite hydrogel named as SA-g-poly(AAm)/HL-CoFe2O4 was produced by grafting polyacrylamide (AAm) onto sodium alginate (SA) in the presence of a magnetic composite recognized as HL-CoFe2O4, where HL represents hydrolyzed Luffa Cylindrica. By employing FT-IR, XRD, VSM, SEM, EDX-Map, BET, DLS, HPLC, and TGA techniques, morphological evaluation and characterization of the adsorbents were carried out. The performance of the adsorption process was studied under varying operational conditions including pH, temperature, contact duration, initial concentration of pollutant ions, and adsorbent dosage. HPLC analysis proved the non-toxic structure of the bionanocomposite hydrogel. The number of unreacted acrylamide monomers within the hydrogel matrix was measured at 20.82 mg/kg. The optimum conditions was discovered to be pH = 6, room temperature, adsorbent dosage of 1 of g.L-1, initial Ni2+ concentration of 10 mg.L-1, and contact time of 100 min, and the maximum adsorption efficiency at optimal state was calculated as 70.09, 90.25, and 93.83 % for SA-g-poly (AAm), SA-g-poly(AAm)/HL, and SA-g-poly(AAm)/HL-CoFe2O4 samples, respectively. Langmuir isotherm model was in good agreement with the experimental data and the maximum adsorption capacity of SA-g-poly(AAm), SA-g-poly(AAm)/HL, and SA-g-poly(AAm)/HL-CoFe2O4 samples was calculated to be 31.37, 43.15, and 45.19 mg.g-1, respectively. The adsorption process, according to kinetic studies, follows a pseudo-second-order kinetic model. Investigations on thermodynamics also demonstrated that the process is exothermic and spontaneous. Exploring the interference effect of co-existing ions showed that the adsorption efficiency has decreased with concentration enhancement of Ca2+ and Na+ cations in aqueous medium. Furthermore, the adsorption/desorption assessments revealed that after 8 consecutive cycles, there had been no noticeable decline in the adsorption effectiveness. Finally, actual wastewater treatment outcomes demonstrated that the bionanocomposite hydrogel successfully removes heavy metal pollutants from shipbuilding industry effluent. Therefore, the findings revealed that the newly fabricated bionanocomposite hydrogel is an efficient, cost-effective, easy-separable, and green adsorbent that could be potentially utilized to remove divalent nickel ions from wastewater.

3D-Printed MOFs/Polymer Composite as a Separatable Adsorbent for the Removal of Phenylarsenic Acid in the Aqueous Solution

Metal-organic frameworks (MOFs) are emerging as advanced nanoporous materials to remove phenylarsenic acid, p-arsanilic acid (p-ASA), and roxarsone (ROX) in the aqueous solution, while MOFs are often present as powder state and encounter difficulties in recovery after adsorption, which greatly limit their practical application in the aqueous environments. Herein, MIL-101 (Fe), a typical MOF, was mixed with sodium alginate and gelatin to prepare MIL-101@CAGE by three-dimensional (3D) printing technology, which was then used as a separatable adsorbent to remove phenylarsenic acid in the aqueous solution. The structure of 3D-printed MIL-101@CAGE was first characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and thermogravimetry and differential thermogravimetry (TG-DTG). The octahedral morphology of MIL-101 (Fe) was found unchanged during the 3D printing process. Then, the adsorption process of MIL-101@CAGE on phenylarsenic acids was systematically investigated by adsorption kinetics, adsorption isotherms, adsorption thermodynamics, condition experiments, and cyclic regeneration experiments. Finally, the adsorption mechanism between MIL-101@CAGE and phenylarsenic acid was further investigated. The results showed that the Langmuir, Freundlich, and Temkin isotherms were well fit, and according to the Langmuir fitting results, the maximum adsorption amounts of MIL-101@CAGE on p-ASA and ROX at 25 °C were 106.98 and 120.28 mg/g, respectively. The removal of p-ASA and ROX by MIL-101@CAGE remained stable over a wide pH range and in the presence of various coexisting ions. The regeneration experiments showed that the 3D-printed MIL-101@CAGE could still maintain a more than 90% removal rate after five cycles. The adsorption mechanism of this system might include π-π stacking interactions between the benzene ring on the phenylarsenic acids and the organic ligands in MIL-101@CAGE, hydrogen-bonding, and ligand-bonding interactions (Fe-O-As). This study provides a new idea for the scale preparation of a separatable and recyclable adsorbent based on MOF material for the efficient removal of phenylarsenic acid in the aqueous solution.

Utilization of electron beam irradiated carboxymethyl cellulose/polyvinyl alcohol/banana peels composite film for remediation of dyes from wastewater

In this work, polymeric composite films were fabricated utilizing stable, non-toxic, soluble, low-cost, good mechanical, and biocompatible polymers such as CMC and PVA with the waste of one of the most current fruits consumed worldwide banana peel waste (BP) as a filler. Sequences of carboxymethyl cellulose/polyvinyl alcohol/banana peel (CMC/PVA/BP) composite films with various amounts of BP utilizing eco-friendly technique (electron beam) (EB) irradiation were prepared to eliminate common hazardous organic pollutants such as methylene blue (MB) dye from its solutions. Physical characteristics like; swelling and gel % were examined. The chemical structure, thermal stability, and surface morphology were examined utilizing FT-IR, TGA, DSC, XRD, EDX, and SEM. Additionally, the UV/Vis spectroscopy study was investigated to study the impact of the various parameters such as irradiation, contact time, pH, temperature, adsorbent dosage, and initial concentration on removal efficiency % of MB dye onto the prepared composite films. The adsorption process fitted with the Langmuir model, pseudo-second-order kinetic model, endothermic, favorable, and spontaneous. The adsorption capacity of MB dye onto the CMC/PVA/BP composite film was 19.6 mg/g at the optimum conditions: irradiation dose = 20 kGy, contact time = 120 min, pH = 10, temperature = 25 °C, adsorbent dosage = 0.1 g and initial conc. = 10 mg/L.

Propensity of a low-cost adsorbent derived from agricultural wastes to interact with cationic dyes in aqueous solutions

Ash collected from thrown-away by-products while preparing a popular traditional food additive, kolakhar of the Assamese community of North East, India, was used as an alternate cost-effective, porous bioadsorbent option from the conventional activated carbon for the purification of carcinogenic dyes laden water. The base material for kolakhar preparation was taken from the discarded banana stem waste to stimulate agricultural waste management. Methylene blue (MB) and basic fuchsin (BF) dyes were used as model cationic dyes. Characterization techniques like CHN, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission-scanning electron microscope (FE-SEM), energy dispersive X-ray (EDX), and Brunauer-Emmett-Teller (BET) analysis of the prepared banana stem ash (BSA) reveal the presence of high inorganic contents and functional groups in the irregular, porous bioadsorbent with surface area 55.534 m2 g-1. Various regulating parameters studied to optimize the adsorption capacity of BSA were bioadsorbent dose (0.1-3 g/L), temperature (298-318 K), contact time (0-150 min), pH (2-9), and initial dye concentrations (10-40 mg/L). Non-linear kinetic models suggested Elovich for both MB and BF adsorption, while the non-linear isotherm model suggested Langmuir and Temkin for MB and BF adsorption, respectively, as best-fitted curves. The monolayer adsorption capacity (qm) for MB and BF was 15.22 mg/g and 24.08 mg/g at 318 K, respectively, with more than 95% removal efficiency for both dyes. The thermodynamic parameters studied indicated that the adsorption is spontaneous. The ∆H0 values of MB and BF adsorptions were 2.303 kJ/mol (endothermic) and - 29.238 kJ/mol (exothermic), respectively.

Adsorption kinetics of methylene blue from wastewater using pH-sensitive starch-based hydrogels

In this work, starch/poly(acylic acid) hydrogels were synthesized through a free radical polymerization technique. The molar ratios of acrylic acid to N,N'-methylenebisacrylamide were 95:5, 94:6, and 93:7. The samples exhibited an amorphous porous structure, indicating that the size of the pores was contingent upon the amount of cross-linking agent. The quantity of acrylic acid in structure rose with a little increase in the amount of the cross-linking agent, which improved the hydrogels' heat stability. The swelling characteristics of the hydrogels were influenced by both the pH level and the amount of cross-linking agent. The hydrogel with a ratio of 94:6 exhibited the highest degree of swelling (201.90%) at a pH of 7.4. The dominance of the Fickian effect in regulating water absorption in the synthesized hydrogels was demonstrated, and the kinetics of swelling exhibited agreement with Schott's pseudo-second order model. The absorption of methylene blue by the hydrogels that were developed was found to be influenced by various factors, including the concentration of the dye, the quantity of the cross-linking agent, the pH level, and the duration of exposure. The hydrogel 95:5 exhibited the highest adsorption effectiveness (66.7%) for the dye solution with a concentration of 20 mg/L at pH 10.0. The examination of the kinetics and isotherms of adsorption has provided evidence that the process of physisorption takes place on heterogeneous adsorbent surfaces and can be explained by an exothermic nature.

Modified biochar prepared from Retinervus luffae fructus for dyes adsorption and aerobic sludge granulation

Retinervus luffae fructus biochar (RLFB) and ZnCl2 pretreated Retinervus luffae fructus biochar (ZRLFB) were prepared by pyrolysis. The as-prepared biochar was investigated for its applicability as a dye adsorber using sunset yellow (SY) and basic red 46 (BR46) dyes. Additionally, ZRLFB was used for the experimental cultivation of granular sludge. The results indicated that the adsorption effect of ZRLFB on the two dyes was higher than RLFB. The adsorption of RLFB to SY was related to the Langmuir and Freundlich models, whereas the adsorption of RLFB-BR46, ZRLFB-SY, and ZRLFB-BR46 was more in line with the Langmuir model. The adsorption process of dyes on two kinds of biochars can be described using pseudo-second-order mechanisms. The maximum adsorption capacity obtained was 1.9586 (RLFB-SY), 6.1286 (RLFB-BR46), 49.2611 (ZRLFB-SY), and 181.4882 mg g^-1 (RLFB-BR46). The result of the SBR operation showed that ZRLFB can potentially be applied as the core of aerobic granular sludge.

Highly selective adsorption of Hg (II) from aqueous solution by three-dimensional porous N-doped starch-based carbon

For the first time, N-doped carbon materials with 3D porous-layered skeleton structure was synthesized through a one-step co-pyrolysis method, which was fabricated by co-pyrolysis of natural corn starch and melamine using metal catalysts (Ni (II) and Mn (II)). The 3D-NC possessed a heterogeneously meso-macroporous surface with a hierarchically connected sheet structure inside. Batch adsorption experiments suggested that highly selective adsorption of Hg (II) by the 3D-NC could be completed within 90 min and had maximum adsorption capacities as high as 403.24 mg/g at 293 K, pH = 5. The adsorption mechanism for Hg (II) was carefully evaluated and followed the physical adsorption, electrostatic attraction, chelation, and ion exchange. Besides, thermodynamic study demonstrated that the Hg (II) adsorption procedure was spontaneous, endothermic, and randomness. More importantly, the 3D-NC could be regenerated and recovered well after adsorption-desorption cycles, showing a promising prospect in the remediation of Hg (II)-contaminated wastewater.

Synthesis and Characterization of Orange Peel Modified Hydrogels as Efficient Adsorbents for Methylene Blue (MB)

In recent years, due to the developments in the textile industry, water contaminated with synthetic dyes such as methylene blue (MB) has become an environmental threat based on the possible impacts in terms of chemical and biochemical demand, which leads to disturbance in aquatic plants photosynthesis, besides their possible toxicity and carcinogenicity for humans. In this work, an adsorbent hydrogel is prepared via free radical polymerization comprising acrylic acid (PAA) as a monomer and orange peel (OP) as a natural modifier rich in OH and COOH present in its cellulose and pectin content. The resulting hydrogels were optimized in terms of the content of OP and the number of cross-linkers and characterized morphologically using Scanning electron microscopy. Furthermore, BET analysis was used to follow the variation in the porosity and in terms of the surface area of the modified hydrogel. The adsorption behavior was found to follow pseudo-second-order as a kinetic model, and Langmuir, Freundlich, and Temkin isotherm models. The combination of OP and PAA has sharply enhanced the adsorption percent of the hydrogel to reach 84% at the first 10 min of incubation with an adsorption capacity of more than 1.93 gm/gm. Due to its low value of pHPZc, the desorption of MB was efficiently performed at pH 2 using HCl, and the desorbed OP-PAA were found to be reusable up to ten times without a decrease in their efficiency. Accordingly, OP-PAA hydrogel represents a promising efficient, cost-effective, and environmentally friendly adsorbent for MB as a model cationic dye that can be applied for the treatment of contaminated waters.

Cellulose/nanocellulose superabsorbent hydrogels as a sustainable platform for materials applications: A mini-review and perspective

Superabsorbent hydrogels (SAH) are crosslinked three-dimensional networks distinguished by their super capacity to stabilize a large quantity of water without dissolving. Such behavior enables them to engage in various applications. Cellulose and its derived nanocellulose can become SAHs as an appealing, versatile, and sustainable platform because of abundance, biodegradability, and renewability compared to petroleum-based materials. In this review, a synthetic strategy that reflects starting cellulosic resources to their associated synthons, crosslinking types, and synthetic controlling factors was highlighted. Representative examples of cellulose and nanocellulose SAH and an in-depth discussion of structure-absorption relationships were listed. Finally, various applications of cellulose and nanocellulose SAH, challenges and existing problems, and proposed future research pathways were listed.

Melanins from the Lichens Lobaria pulmonaria and Lobaria retigera as Eco-Friendly Adsorbents of Synthetic Dyes

Synthetic dyes are widely used in the industry; they are chemically stable, difficult to neutralize, and therefore they are a threat to the environment when released into wastewaters. The dyes have a significant impact on plant performance by impairing photosynthesis, inhibiting growth, and entering the food chain and may finally result in the toxicity, mutagenicity and carcinogenicity of food products. Implementation of the dark piment melanin for the adsorption of the synthetic dyes is a new ecologically friendly approach for bioremediation. The aim of the present work was to study the physico-chemical characteristics of melanins from the lichens Lobaria pulmonaria and Lobaria retigera, analyze their adsorption/desorption capacities towards synthetic dyes, and assess the capacity of melanins to mitigate toxicity of the dyes for a common soil bacterium Bacillus subtilis. Unique chelating properties of melanins determine the perspectives of the use of these high molecular weight polymers for detoxification of xenobiotics.

Environmentally friendly hydrogel: A review of classification, preparation and application in agriculture

Superabsorbent hydrogel (SH) is three-dimensional (3D) cross-linked hydrophilic polymer that can absorb and retain large quantities of water or other aqueous solutions. SH is made of water-affinity monomers and is widely used in biomedicine, wastewater treatment, hygiene and slow-release fertilizers (SRFs). This article focused on the preparation methods of SH, superabsorbent hydrogel composite and the application of SH in agriculture. By selecting various synthetic technologies and cross-linking agents, a series of chemical cross-linking or physical networks can be designed and tailored to meet specific applications. In view of the excellent characteristics of water absorption, biodegradability, water retention and slow-release capacity, SH occupies a dominant position in the SRFs market. In this work, the agricultural application of SH in double coated SRFs and nutrients carriers is also discussed. Some mechanisms related to the nutrient release were analyzed by mathematical models. In addition, some agronomic benefits of using superabsorbent hydrogels in improving water absorption, water holding capacity and increasing crop yields were also discussed. Although SH has certain shortcomings, from the perspective of long-term development, it will further show great potential in sustainable agriculture.

Locust Bean gum-based hydrogels embedded magnetic iron oxide nanoparticles nanocomposite: Advanced materials for environmental and energy applications

This paper reports a simple method of designing and synthesizing magnetic iron oxide (IO) integrated locust bean gum-cl-polyacrylonitrile hydrogel nanocomposites (LBG-cl-PAN/IONP) by in situ mineralization of iron ions in a hydrogel matrix. A two-step gel crosslink method followed by co-precipitation method was used to prepare these novel hydrogels embedded with magnetic iron oxide nanoparticles. The LBG-cl-PAN/IONP hydrogel nanocomposite (HNC) were tested in batch adsorption experiments for their ability to remove a cationic dyes, methylene blue (MB) & Methyl violet (MV), from aqueous solution. In order to analyze the LBG-cl-PAN/IONP HNC, FTIR, XRD, XPS, VSM, TEM, and EDX techniques were applied. Numerous operating parameters were studied, including the amount of adsorbent, the contact time, pH, temperature, the dye concentration, and the coexisting ion concentration. According to the Langmuir isotherm model, MB and MV had maximum monolayer adsorptive capacities of 1250 and 1111 mg/g, respectively. LBG-cl-PAN/IONP HNC controlled IONP oxidation as well as sustained adsorptive removal over a wide pH range (7-10). The key mechanism of adsorption consisted of electrostatic interaction and ion exchange. For successful use in successive cycles after regeneration using HNO₃ as eluent, the LBG-cl-PAN/IONP HNC can easily be reused. As a material, the LBG-cl-PAN/IONP HNC is a promising sorbent or composite material for removing toxic dyes from water, and therefore can be applied to enhance water and wastewater treatment technology. Additionally, we have briefly evaluated LBG-cl-PAN/IONP HNC for antibacterial and supercapacitor applications. According to our knowledge, this is the first report describing the use of LBG-cl-PAN/IONP HNC multifunctional efficacy as an excellent sorbent, antibacterial and electrochemical supercapacitor applications.

Recyclable Composite Membrane of Polydopamine and Graphene Oxide-Modified Polyacrylonitrile for Organic Dye Molecule and Heavy Metal Ion Removal

Developing efficient and recyclable membranes for water contaminant removal still remains a challenge in terms of practical applications. Herein, a recyclable membrane constituted of polyacrylonitrile-graphene and oxide-polydopamine was fabricated and demonstrated efficient adsorption capacities with respect to heavy metal ions (62.9 mg g^-1 of Cu²⁺ ion, CuSO₄ 50 mg L^-1) and organic dye molecules (306.7 mg g^-1 of methylene blue and 339.6 mg g^-1 of eriochrome black T, MB/EBT 50 mg L^-1). The polyacrylonitrile fibers provide the skeleton of the membrane, while the graphene oxide and polydopamine endow the membrane with hydrophilicity, which is favorable for the adsorption of pollutants in water. Benefitting from the protonation and deprotonation effects of graphene oxide and polydopamine, the obtained membrane demonstrated promotion of the selective adsorption or desorption of pollutant molecules. This guarantees that the adsorbed pollutant molecules can be desorbed promptly from the membrane through simple pH adjustment, ensuring the reusability of the membrane. After ten adsorption-desorption cycles, the membrane could still maintain a desirable adsorption capacity. In addition, compared with other, similar membranes reported, this composite membrane displays the highest mechanical stability. This work puts forward an alternative strategy for recyclable membrane design and expects to promote the utilization of membrane techniques in practical wastewater treatment.

Recent advances in biodecolorization and biodegradation of environmental threatening textile finishing dyes

Organic nature of dyes and their commercially made products are widely utilized in many industries including paper, cosmetics, pharmaceuticals, photography, petroleum as well as in textile manufacturing. The textile industry being the top most consumer of a large variety of dyes during various unit processes operation generates substantial amount of wastewater; hence, nominated as "Major Polluter of Potable Water". The direct discharge of such effluents into environment poses serious threats to the functioning of biotic communities of natural ecosystems. The detection of these synthetic dyes is considered as relatively easy, however, it is extremely difficult to completely eliminate them from wastewater and freshwater ecosystems. Aromatic chemical structure seems to be the main reason behind low biodegradability of these dyes. Currently, various physiochemical and biological methods are employed for their remediation. Among them, microbial degradation has attracted greater attention due to its sustainability, high efficiency, cost effectiveness, and eco-friendly nature. The current review presents recent advances in biodegradation of industrial dyes towards a sustainable and tangible technological innovative solutions as an alternative to existing conventional physicochemical treatment processes.

Synergistic sorption performance of karaya gum crosslink poly(acrylamide-co-acrylonitrile) @ metal nanoparticle for organic pollutants

In this work, we tailor facile hydrogels nanocomposite (HNC) based on sustainable karaya gum for water treatment. Karaya gum crosslink poly(acrylamide-co-acrylonitrile) @ silver nanoparticle (KG-cl-P(AAm-co-AN)@AgNPs) HNC were made by an aqueous free radical in situ crosslink copolymerization of acrylamide (AAm) and acrylic acid (AA) in aqueous solution of KG-stabilized AgNPs. FTIR, XRD, DTA-TGA, SEM, and TEM were used to characterize HNC. The hydrogels' swelling, diffusion, and network characteristics were investigated. The removal efficiency of HNC was found to be 99% at pH 8 for a crystal violet (CV), dose of 0.02 g after 1 h. Dye adsorption by these hydrogels was also investigated in terms of isotherms, and kinetics. The dye's exceptionally high adsorption capacity on HNC for CV removal is explained by H-bonding interactions, as well as dipole-dipole and electrostatic interactions between anionic adsorbent and cationic dye molecules (Qmax, 1000 mg/g). The HNC can be regenerated with 0.1 M HCl and reused at least 10 times maintaining over 68% dye removal. The loading of AgNPs into the polymeric matrix of KG-cl-P(AAm-co-AN) significantly increases the removal percentage of CV dye from its aqueous solution, according to this study.

Bio-packaging based on cellulose acetate from banana pseudostem and containing Butia catarinensis extracts

Banana (Musa acuminata) pseudostem cellulose was extracted and acetylated (CA) to prepare membranes with potential use as bio-packages. The CA membrane was embedded by Butia seed (CA-BS) or Butia pulp (CA-BP) extracts obtained from Butia catarinenses (Butia). The produced CA, CA-BS, and CA-BP membranes were evaluated for their physical-chemical, mechanical, thermal, and antibacterial properties. The process for obtaining the cellulose yielded a material with about 92.17% cellulose (DS = 2.85). The purity, cellulose degree acetylation, and the incorporation of Butia extracts into the membranes were confirmed by FTIR. The CA-BS and CA-BP membranes showed a smaller contact angle and higher swelling ratio than the CA membrane. Furthermore, Butia seed or pulp extracts reduced the elastic modulus and deformation at break compared to the CA membrane. The DSC analysis suggested the compatibility between sections and the CA matrix, whereas the TGA analysis confirmed the thermal stability of the membranes. Moreover, less than 1% of the Butia seed and pulp extracts were put into a food simulant media from the membrane. Finally, the CA-BS and CA-BP membranes could inhibit the growth of Staphylococcus aureus and Escherichia coli on their surface, confirming the potential use of these membranes as bio-packaging for food preservation.

A Comprehensive Review on Natural Fibers: Technological and Socio-Economical Aspects

Asian countries have abundant resources of natural fibers, but unfortunately, they have not been optimally utilized. The facts showed that from 2014 to 2020, there was a shortfall in meeting national demand of over USD 2.75 million per year. Therefore, in order to develop the utilization and improve the economic potential as well as the sustainability of natural fibers, a comprehensive review is required. The study aimed to demonstrate the availability, technological processing, and socio-economical aspects of natural fibers. Although many studies have been conducted on this material, it is necessary to revisit their potential from those perspectives to maximize their use. The renewability and biodegradability of natural fiber are part of the fascinating properties that lead to their prospective use in automotive, aerospace industries, structural and building constructions, bio packaging, textiles, biomedical applications, and military vehicles. To increase the range of applications, relevant technologies in conjunction with social approaches are very important. Hence, in the future, the utilization can be expanded in many fields by considering the basic characteristics and appropriate technologies of the natural fibers. Selecting the most prospective natural fiber for creating national products can be assisted by providing an integrated management system from a digitalized information on potential and related technological approaches. To make it happens, collaborations between stakeholders from the national R&D agency, the government as policy maker, and academic institutions to develop national bioproducts based on domestic innovation in order to move the circular economy forward are essential.

Facile Preparation and Dye Adsorption Performance of Poly(N-isopropylacrylamide-co-acrylic acid)/Molybdenum Disulfide Composite Hydrogels

Using N-isopropylacrylamide (NIPAM) and acrylic acid (AAc) as monomers, N,N'-methylenebisacrylamide (MBA) as a cross-linking agent, and molybdenum disulfide (MoS2) as functional particles, a P(NIPAM-co-AAc)/MoS2 composite hydrogel was prepared by free radical polymerization initiated by ultraviolet light. The results of Fourier transform infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy show that MoS2 has been successfully introduced into the P(NIPAM-co-AAc) system, and the obtained composite hydrogel has a porous network structure. Studies on the swelling property and dye adsorption performance show that the addition of MoS2 can increase the swelling ratio of P(NIPAM-co-AAc) hydrogels to a certain extent and can significantly improve the ability of the P(NIPAM-co-AAc) hydrogel to adsorb methylene blue (MB). The adsorption process of MB by the composite hydrogels conforms to the pseudo-second-order kinetics and the Langmuir isotherm adsorption models. The estimated equilibrium adsorption capacity (Q m) using the Langmuir isotherm model can reach 1258 mg/g, mainly due to the electrostatic interaction between the negatively charged groups -COO- and MoS2 particles on the network structure and the positively charged dye MB. The adsorption of MB by P(NIPAM-co-AAc)/MoS2 composite hydrogels depends on the temperature during adsorption. Compared with room temperature, a high temperature of 40 °C above the poly(N-isopropylacrylamide) (PNIPAM) phase transition temperature (∼32 °C) leads to a decreased adsorption capacity of the P(NIPAM-co-AAc)/MoS2 composite hydrogel for MB due to the enhanced hydrophobic properties of the network structure and the decrease of the swelling ratio. The prepared hydrogel material can be used as a good adsorbent for dyes, which is promising in wastewater treatment.

Designing cellulose hydrogels from non-woody biomass

Hydrogels are an attractive system for a myriad of applications. While most hydrogels are usually formed from synthetic materials, lignocellulosic biomass appears as a sustainable alternative for hydrogel development. The valorization of biomass, especially the non-woody biomass to meet the growing demand of the substitution of synthetics and to leverage its benefits for cellulose hydrogel fabrication is attractive. This review aims to present an overview of advances in hydrogel development from non-woody biomass, especially using native cellulose. The review will cover the overall process from cellulose depolymerization, dissolution to crosslinking reaction and the related mechanisms where known. Hydrogel design is heavily affected by the cellulose solubility, crosslinking method and the related processing conditions apart from biomass type and cellulose purity. Hence, the important parameters for rational designs of hydrogels with desired properties, particularly porosity, transparency and swelling characteristics will be discussed. Current challenges and future perspectives will also be highlighted.

Villi-like poly(acrylic acid) based hydrogel adsorbent with fast and highly efficient methylene blue removing ability

Organic dye-containing wastewater has become an increasingly serious environmental problem due to the rapid development of the printing and dyeing industry. Hydrogel is a promising adsorbent for organic dyes because of its unique three-dimension network structure and versatile functional groups. Though many efforts have been made in hydrogel adsorbents recently, there is still a critical challenge to fabricate hydrogel adsorbent with high adsorption capacity and high efficiency at the same time. To address this concern, we developed a calcium hydroxide nano-spherulites/poly(acrylic acid -[2-(Methacryloxy)ethyl]trimethyl ammonium chloride) hydrogel adsorbent with novel villi-like structure. The hydrogels were prepared through a simple free radical copolymerization method using calcium hydroxide nano-spherulites as crosslinker. The resultant hydrogel adsorbents showed a maximum adsorption capacity of 2249 mg/g in a 400 mg/L methylene blue solution and a high removal ratio of 98% in 1 h for a 50 mg/L methylene blue solution. In addition, the adsorption behaviors of our hydrogel adsorbents could be well described by pseudo-second-order kinetic model and Langmuir adsorption isotherm model. Furthermore, this kind of hydrogel adsorbent showed selective adsorption behavior for methylene blue. Altogether, the hydrogel adsorbent developed in this work has a high capacity and high efficiency in organic dye removing and promised a great potential in wastewater treatment application.

Microwave assist sorption of crystal violet and Congo red dyes onto amphoteric sorbent based on upcycled Sepia shells

A new sorbent based on Sepia shells (cuttlefish bones) has been synthesized (SSBC) and tested for the sorption of cationic dye (crystal violet, CV) and an anionic dye (congo red, CR). SSBC was produced by reaction of sepia shells powder with urea in the presence of formaldehyde. In the first part of the work, the sorbent was characterized using scanning electron microscopy, energy dispersive X-ray analysis, Fourier-transform infra-red spectrometry and titration (for determining pH_PZC). In a second step, sorption properties were tested on the two dyes through the study of pH effect, sorbent dosage, temperature and ionic strength; the sorption isotherms and uptake kinetics were analyzed at the optimum pH: Langmuir equation fits isotherm profiles while the kinetic profile can be described by the pseudo-second order rate equation. Maximum sorption capacities reach up to 0.536 mmol g^-1 for CV and 0.359 mmol g^-1 for CR, at pH 10.6 and 2.4, respectively. The comparison of sorption properties at different temperatures shows that the sorption is endothermic. Processing to the sorption under microwave irradiation (microwaved enforced sorption, MES) increases mass transfer and a contact time as low as 1 min is sufficient under optimized conditions (exposure time and power) reaching the equilibrium, while 2-3 h were necessary for "simple" sorption. Dye desorption was successfully tested using 0.5 M solutions of NaOH and HCl for the removal of CR and CV, respectively. The sorbent can be re-used for a minimum of four cycles of sorption/desorption. Finally, the sorbent was successfully tested on spiked tap water and real industrial wastewater.

Tailored Lignocellulose-Based Biodegradable Matrices with Effective Cargo Delivery for Crop Protection

Controlled release and targeted delivery of agrochemicals are crucial for achieving effective crop protection with minimal damage to the environment. This work presents an innovative and cost-effective approach to fabricate lignocellulose-based biodegradable porous matrices capable of slow and sustained release of the loaded molecules for effective crop protection. The matrix exhibits tunable physicochemical properties which, when coupled with our unique "wrap-and-plant" concept, help to utilize it as a defense against soil-borne pests while providing controlled release of crop protection moieties. The tailored matrix is produced by mechanical treatment of the lignocellulosic fibers obtained from banana plants. The effect of different extents of mechanical treatments of the lignocellulosic fibers on the protective properties of the developed matrices is systematically investigated. While variation in mechanical treatment affects the morphology, strength, and porosity of the matrices, the specific composition and structure of the fibers are also capable of influencing their release profile. To corroborate this hypothesis, the effect of morphology and lignin content changes on the release of rhodamine B and abamectin as model cargos is investigated. These results, compared with those of the matrices developed from non-banana fibrous sources, reveal a unique release profile of the matrices developed from banana fibers, thereby making them strong candidates for crop protection applications.

Superior adsorption capacity of functionalised straw adsorbent for dyes and heavy-metal ions

Dyes and heavy-metal ions are common pollutants in printing and dyeing wastewater, and are thus attracting considerable attention. Herein, an eco-friendly straw-based adsorbent, WS-CA-AM, was prepared by grafting with acrylamide (AM) and citric acid (CA) groups to remove representative dyes and heavy metals from aqueous solution. The adsorption capacities of WS-CA-AM for methyl orange (MO) and methylene blue (MB) were 3053.48 and 120.84 mg/g, which were 54 and 3 times those of unmodified straw, respectively. Moreover, the adsorption capacities for MB, MO, Cr₂O₇^2- and Cu²⁺ in the mixed system increased by 210%, 133%, 196% and 151%, respectively, compared with those in the single system. The significant increase in adsorption capacity can be attributed to the collaborative effect through electrostatic attraction. The functional groups and adsorbed pollutants all served as adsorption sites for pollutants. These results indicate that WS-CA-AM is a potential applicant for the removal of dyes and heavy-metal ions from mixed aqueous solution.

Controlled Fabrication of K2Ti8O17 Nanowires for Highly Efficient and Ultrafast Adsorption toward Methylene Blue

Advanced adsorbents need high adsorption rate and superior adsorption capability to clean up organic methylene blue (MB) from wastewater. We prepared K₂Ti₈O₁₇ nanowires grown along the [0 1 0] direction with a one-step hydrothermal method. The K₂Ti₈O₁₇ nanowires with tens of nanometers in diameter and tens of micrometers in length were achieved with smooth surfaces and twisted wire-like morphology. The K₂Ti₈O₁₇ nanowires exhibit high uptake capacity of ∼208.8 mg·g^-1 in the MB removal under equilibrium pH = 7. The adsorption equilibrium of MB onto the K₂Ti₈O₁₇ adsorbent is achieved with a 97% removal rate of MB within only ∼21 min, which is the shortest adsorption time among the recently reported inorganic adsorbents toward MB. The adsorption process has a good agreement with the well-known pseudo-second-order kinetic model (k₂ = 0.2) and the Langmuir isotherm model. Fourier transform infrared measurements suggest that the adsorption can be assigned to the hydrogen bonding and electrostatic attraction between MB and K₂Ti₈O₁₇. This ultrafast removal ability is due to the larger (0 2 0) interplanar spacing and zigzag surface structure of the nanowires, which provide abundant active adsorption sites. Thermodynamic parameters reflect the spontaneous, exothermic, and feasible uptake of MB. Besides, K₂Ti₈O₁₇ nanowires enjoy high adsorptive ability for chromium(VI) ions and photocatalytic removal toward NO. This work highlights the great significance of K₂Ti₈O₁₇ nanowires as a low-cost promising material used for the adsorptive elimination of organic contaminations in fast water purification on a large scale.