Anionic Pollutants Research Articles

β-Ketoenamine Covalent Organic Frameworks-Effects of Functionalization on Pollutant Adsorption.

Water pollution due to global economic activity is one of the greatest environmental concerns, and many efforts are currently being made toward developing materials capable of selectively and efficiently removing pollutants and contaminants. A series of β-ketoenamine covalent organic frameworks (COFs) have been synthesized, by reacting 1,3,5-triformylphloroglucinol (TFP) with different C2-functionalized and nonfunctionalized diamines, in order to evaluate the influence of wall functionalization and pore size on the adsorption capacity toward dye and heavy metal pollutants. The obtained COFs were characterized by different techniques. The adsorption of methylene blue (MB), which was used as a model for the adsorption of pharmaceuticals and dyes, was initially evaluated. Adsorption studies showed that –NO2 and –SO3H functional groups were favorable for MB adsorption, with TpBd(SO3H)2-COF [100%], prepared between TFP and 4,4′-diamine- [1,1′-biphenyl]-2,2′-disulfonic acid, achieving the highest adsorption capacity (166 ± 13 mg g−1). The adsorption of anionic pollutants was less effective and decreased, in general, with the increase in –SO3H and –NO2 group content. The effect of ionic interactions on the COF performance was further assessed by carrying out adsorption experiments involving metal ions. Isotherms showed that nonfunctionalized and functionalized COFs were better described by the Langmuir and Freundlich sorption models, respectively, confirming the influence of functionalization on surface heterogeneity. Sorption kinetics experiments were better adjusted according to a second-order rate equation, confirming the existence of surface chemical interactions in the adsorption process. These results confirm the influence of selective COF functionalization on adsorption processes and the role of functional groups on the adsorption selectivity, thus clearly demonstrating the potential of this new class of materials in the efficient and selective capture and removal of pollutants in aqueous solutions.

Zr-Based Metal–Organic Framework Nanocrystals for Water Remediation

A series of derivatives of the Zr-based MOF UiO-66 were synthesized, fully characterized, and tested for their efficiency in the adsorption and removal of the highly toxic elements lead (Pb(II)), cadmium (Cd(II)), arsenate As(V), and selenite Se(IV). Different structural engineering techniques were employed to alter the properties of the Zr-MOFs, such as linker functionalization and defect creation to increase the density of adsorption sites. The functionalization of the UiO-66-based structures with carboxylate groups increased the removal efficiency of Pb(II) cations by more than 70% and that of Cd(II) cations by more than 60% to reach 125.2 and 69.1 mg/g, respectively. Moreover, the induced cluster defects were found to be the preferred adsorption sites of the anion pollutants. The adsorption of As(V) and Se(IV) by the high-defect UiO-66-200FA was 132.5 and 30.8 mg/g, respectively, which was higher than that of the less defect UiO-66, while almost no adsorption was achieved by UiO-66(COOH)2. Furthermore, a multivariate (MTV-MOF) approach was employed to investigate the effect of the functional groups on the diffusion of the adsorbates within the porous networks. Interestingly, adsorption equilibrium was reached within minutes for the best-performing MOFs, highlighting their potential to be used in practical water treatment applications. Finally, chemical adsorption seemed to be dominant among binding mechanisms for all the pollutants, which were analyzed in detail to determine the characteristics that govern the adsorption efficiency of UiO-66-based adsorbents. The conclusions provided by this comprehensive study help serve as a guideline for future researchers aiming to employ UiO-66-based adsorbents by providing them with a deep understanding of the design strategies required to maximize the performance of this robust MOF.

High capacity for selective adsorption of anionic pollutants by a silver(I) 3D cationic supramolecular constructed from a flexible dithione ligand

A new cationic 3D-supramolecular coordination polymer namely, {[Ag3(Prbit)2 (CF3SO3)] [PF6]2}n (Ag-SCP) was designed, synthesized, structurally elucidated by X-ray crystallography and converted into the nano-sized particles in order to use it for further applications. In its asymmetric unit, three different AgI centers with three distinguished coordination geometries were detected. The uncoordinated PF6-anions neutralize the positive charge associated with the complex. The structure was extended by the intermolecular hydrogen bonding interactions to form a 3D supramolecular network structure. The ligand has an anti-gauche conformation. The polymer has a substantial potential for adsorption of organic and inorganic pollutants. Furthermore, as a recyclable promising prototype the nano–sized polymer displays a fast, efficient and reversible adsorption of Cr(VI) from the Cr(VI)-containing aqueous solutions. The influence of various factors such as initial concentration of the Cr(VI) ions, weight of the nano-sized Ag-SCP, pH and contact time on the adsorption efficiency of Cr(VI) were examined by the central composite design (CCD) method. Under the optimum conditions and desirable function value of 1.0, the adsorption percentage of Cr(VI) ions was to be 97%. Regression analysis with an R2 value of 0.99 indicates a satisfactory correlation between the obtained and predicted data. By virtue of these benefits, the presented supramolecular exhibits a high capture yield. Additionally, the adsorption of Cr(VI) by the nano Ag– SCP via anion exchange mechanism was dependent on the nature of the cationic network. Furthermore, the adsorbent exhibits a good capacity and selectivity for the adsorption of anionic dyes from the aqueous solutions.

Superhydrophobic Phosphonium Modified Robust 3D Covalent Organic Framework for Preferential Trapping of Charge Dispersed Oxoanionic Pollutants

AbstractCharge dispersed and less hydrophilic anionic pollutants are often difficult to be preferentially captured by common cationic framework materials. A gamma radiation modification approach is employed to anchor a superhydrophobic phosphonium‐containing coating on a robust crystalline 3D covalent organic framework (COF). By regulating the surface hydrophobicity, the prepared 3DCOF‐g‐VBPPh3Cl is endowed with a strong affinity for charge dispersed and less hydrophilic oxoanions, such as MnO4−, TcO4− and ReO4−, to surmount the Hofmeister bias, which much favors remediation of oxoanionic pollutants in complex aqueous systems. Batch and column experiments with 3DCOF‐g‐VBPPh3Cl in both tap water and simulated groundwater are performed, and rapid sequestration is achieved with removal efficacy up to 99.995%, record‐high distribution coefficient of 1.0 × 108 mL g−1, and desirable priority over competing anions such as Cl−, SO42−, HCO3−, and NO3−, confirming promise for remediation of charge dispersed anionic pollutants. Theoretical calculations reveal a mechanism of preferential capture based on electrostatic and dispersion interaction between charge dispersed anions and 3DCOF‐g‐VBPPh3Cl that effectively competes with solvation of the aqueous anions.

Urchin-like, Surface-Positively Charged, Double-Shelled SnS2@TiO2 for Protecting and Enhancing Adsorption and Photocatalytic Activity to Remove High Concentrations of Anionic Pollutants

Urchin-like, Surface-Positively Charged, Double-Shelled SnS₂@TiO₂ for Protecting and Enhancing Adsorption and Photocatalytic Activity to Remove High Concentrations of Anionic Pollutants

The simultaneous reduction and adsorption for V(V) and Cr(VI) anionic species in aqueous solution by polyethyleneimine cross-linked titanate nanotubes

Treating water containing hazardous V(V) and Cr(VI) by using a efficient and simple method is an urgent need, but still a challenge. Novel binary composites (PEI-TNTs) were successfully synthesized by introducing polyethyleneimine (PEI) onto titanate nanotubes (TNTs) in a cost-effective and facile route, where TNTs and PEI existed as an interior core and an exterior shell. The removal efficiency of PEI-TNTs was highly reliant on the initial solution pH according to the batch adsorption experiments, and the maximum adsorption capacity for V(V) reached 1280.36 mg g−1 at pH 3.0 and for Cr(VI) reached 980.39 mg g−1 at pH 2.0 calculated by the Langmuir model. And PEI-TNTs effectively resisted the interference of various coexisting anions and cations. In simulated mining wastewater experiments, PEI-TNTs still remained fine V(V) and Cr(VI) adsorption capability; and PEI-TNTs could be regenerated and reused for 5 cycles without significantly reducing its removal efficiency. The excellent removal performance mainly owned to the high stability of inorganic skeleton and high surface activity from polymer modification. A comprehensive mechanism was proposed for the adsorption process associating with electrostatic attraction, redox reaction, and chelation. This work provides the theoretical and practical information for the novel inorganic–organic nanomaterials based on titanate nanotubes and polymers for the efficient reduction and adsorption of heavy metal anionic pollutants in water.

Two-Dimensional Cationic Aluminoborate as a New Paradigm for Highly Selective and Efficient Cr(VI) Capture from Aqueous Solution.

Water pollutants existing in their oxyanion forms have high solubility and environmental mobility. To capture these anionic pollutants, cost-effective inorganic materials with cationic frameworks and outstanding removal performance are ideal adsorbents. Herein, we report that two-dimensional (2D) cationic aluminoborate BAC(10) sets a new paradigm for highly selective and efficient capture of Cr(VI) and other oxyanions from aqueous solution. The structure of Cr(VI)-exchanged BAC(10) sample (Cr(VI)@BAC(10), H0.22·Al2BO4.3·(HCrO4)0.22·2.64H2O) has been successfully solved by continuous rotation electron diffraction. The crystallographic data show that the 2D cationic layer of BAC(10) is built by AlO6 octahedra, BO4 tetrahedra, and BO3 triangles. Partial chromate ions exchanged with Cl– ions are located within the interlayer region, which are chemically bonded to the aluminoborate layer. BAC(10) shows faster adsorption kinetics compared to the commercial anion exchange resin (AER) and layered double hydroxides (LDHs), a higher maximum adsorption capacity of 139.1 mg/g than that of AER (62.77 mg/g), LDHs (81.43 mg/g), and a vast majority of cationic MOFs, and a much broader working pH range (2–10.5) than LDHs. Moreover, BAC(10) also shows excellent Cr(VI) oxyanion removal performance for a solution with a low concentration (1–10 mg/L), and the residual concentration can be reduced to below 0.05 mg/L of the WHO drinking water criterion. These superior properties indicate that BAC(10) is a promising material for remediation of Cr(VI) and other harmful oxyanions from wastewater.

Al2O3 encapsulated by calcium alginate as composite for efficient removal of phosphate from aqueous solutions: batch and column studies.

Activated alumina (Al2O3) has been widely used to remove aqueous anionic pollutants such as phosphate for preventing the eutrophication phenomenon. While Al2O3, as a fine powder material, cannot be stably packed into continuous flow treatment, which limits its practical applications. Herein, we proposed a new strategy in which Al2O3 was encapsulated by calcium alginate (CA) to fabricate Al2O3/CA composite, which has relatively large particle size and can be suitable for application in columns. The BET surface area of Al2O3/CA increased to 51.73 m2/g compared with 37.31 m2/g of Al2O3. The maximum adsorption capacity of phosphate on Al2O3/CA was estimated at 1.92-fold compared with that of pure Al2O3 by Langmuir fitting. The main mechanism of phosphate adsorption was the formation of aluminum phosphate precipitation. Moreover, the column studies showed that the adsorption of phosphate on Al2O3/CA was affected by the amount of outer calcium alginate, bed height, influent flow rates and phosphate concentration. This study demonstrated that Al2O3/CA composite has better adsorption capacity and can be used in the dynamic adsorption system as a promising approach for phosphate removal from water.

Effect of amino acids on the stability of anionic pollutants in fly ash blended cement

Fly ash has been used as a cementitious material for solid wastes immobilization. However, fly ash typically contains the hazardous elements Se, Cr, As, and B, and the leachability of these anions is a concern for its reuse. In this study, five amino acids were selected as models of simplified natural organic matter (NOM) in the pedosphere to modify the dissolution tests of Se, Cr, As, and B in ground fly ash blended cement. At the initial pH of 4.7, hydrocalumite and ettringite were easily dissolved, so Ca salt precipitates played an important role in immobilizing oxyanions. However, the stability of Ca salts was weakened by the ligand-promoted dissolution mechanism. In particular, the formation of complexes of H2Asp and HGly with Ca2+ promoted the release of Se, Cr, and As. H2Cys, on the other hand, acted as a reducing reagent to suppress Se and Cr mobility. At the initial pH of 12.0, the stable formation of hydrocalumite and ettringite effectively immobilized the anionic species. Under this condition, aside from the complexation of amino acids with Ca2+, the ion exchange between deprotonated amino acids and oxyanions in hydrocalumite interlayer may also threaten the stability of undesirable anionic species. However, the adsorption of amino acids on the surface of ettringite and hydrocalumite may inhibit their dissolution, resulting in a decrease in Se, Cr, As, and B release. This work provides a reference for understanding the stability of undesirable anionic pollutants in fly ash blended cement when they are exposed to geochemical environments.

Biotemplated synthesis of hollow nickel silicate fiber for organic dye contaminants and its selective adsorption

Silicate is one kind of the fundamental constituent of minerals with the interesting properties, such as environment-friendliness, easily availability and hydrophilic surface chemistry. In this study, cotton fiber as versatile biotemplate is employed to synthesize hollow nickel silicate fibers through hydrothermal treatment and carbonization removal of the template. The as-prepared hollow nickel silicate fiber is rich in hydroxyl group and mesoporous structure according to the characterization of SEM、FTIR、XRD and N2 adsoprtion-desorption measurement. The adsorption performance of hollow nickel silicate fiber for methylene blue (MB) and congo red (CR) dye from the aqueous solution is systematically investigated. The results show that the dye adsorption of HNiSiFs for MB and CR is in accordance with the pseudo-second-order kinetic model, and Langmuir isotherm model is predominant for the monolayer adsorption process with the maximum adsorption capacity of 195.7 and 414.9 mg g−1 for MB and CR, respectively. Moreover, the as-prepared hollow nickel silicate fiber can selectively adsorb anionic dye containing N group from the mixed anionic pollutant solution. The electrostatic interaction of cationic organic molecular or molecular containing N group with HNiSiFs is the main driving force for the effective and specific adsorption.

Removal Arsenic(V) Efficiency and Characteristics Using Modified Basic Oxygen Furnace Slag in Aqueous Solution

Basic oxygen furnace (BOF) slag, the solid waste produced in the steelmaking process, is reused in industry, agriculture and environmental treatment. However, as an adsorbent for wastewater, the removal effect of BOF slag on anionic pollutants needs to be improved. In this study, acid and alkali were used to modify BOF slag, and the removal efficiency and mechanism of arsenic(V) with modified BOF slag in solution were studied. The effects of the As(V) initial concentration, solution pH and reaction time on the removal efficiency were determined by batch experiments, and the removal mechanism of As(V) using modified BOF slag was studied by an adsorption kinetic model and isothermal adsorption model and the Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectral analysis. The results showed that the slag modified by 15% sulfuric acid had the best removal effect on As(V), while the removal effect of As(V) by alkali-modified slag was not ideal. The removal rate of As(V) by acid-modified slag increased with the increase in the initial concentration, decreased slowly with the increase in pH and reached equilibrium in 180 min. The adsorption kinetic model and isothermal adsorption model of As(V) by acid-modified BOF slag showed that the chemical adsorption was the limiting step. The FTIR and XPS analysis results showed that the silicate and ferrite in the acid-modified slag could remove As(V) in the solution by ion exchange to form an arsenate precipitate. Therefore, modified BOF slag can be used as a potential adsorbent for large scale arsenic polluted waterbody to realize the ecological utilization of industrial solid waste.

Kinetic modeling of As release from contaminated soils: Consideration of particle size and co-contamination of Cu

Prediction on the release kinetics of metalloids from soils is challenging due to the physio-chemical heterogeneity of soil and the varying binding abilities of metalloid contaminants on soil. In this study, the kinetics of As(V), together with Cu(II), release from two typical field contaminated soils were investigated by the stirred-flow experiments. We formulated the quantitative models to describe the release kinetics of As(V) from the contaminated soils with consideration of varying soil particle size and presence of Cu(II). The results showed that the release kinetics of As(V) and Cu(II) from different particle size fractions and at different reaction pH was well described by the model. The models also indicated that the bidentate binding sites on goethite were the major contributor for As(V) release, while soil organic matter (SOM) mainly controlled the Cu(II) release. Finer particle size fractions had more significant contributions to As(V) and Cu(II) release due to higher concentrations of reactive metal(loid)s and more reactive adsorbents. Moreover, the models also showed applicability for predicting metal(loid) release from the bulk soils by considering the contribution of each soil particle size fraction, and the kinetic behaviors of two individual contaminants, As(V) and Cu(II), can be modeled independently. Our results provided a modeling framework to predict the release kinetics of metal(loid)s from soils co-contaminated with different cation and anion pollutants with consideration on the effects of physical and chemical heterogeneity of soils.

Synergistic effect of surfactant hexadecyltrimethylammonium supporting and hydrous titania impregnation onto zeolite in enhanced removal of anionic X‐3B dye from aqueous solution

AbstractA new modified zeolite (HTiZFA) was achieved by dually supporting hexadecyltrimethylammonium (HDTMA) and hydrous titania onto synthetic zeolite from coal fly ash via coating HDTMA and Ti(SO4)2 solution respectively, which has an increased adsorption activity for anion X‐3B dye from aqueous solution. HTiZFA with the optimum removal efficiency was obtained at the coating concentration of 13 mmol/L HDTMA, 20.8 mmol/L Ti(SO4)2, and 2 g/L dosage of zeolite. X‐ray fluorescence, X‐ray diffraction (XRD), scanning electron microscope‐energy dispersive, Fourier transform infrared, Brunauer Emmett Teller (BET), and zeta potential analysis are used to characterize the samples (HTiZFA). In XRD spectrum, no typical peak representing anatase TiO2 crystal suggested that hydrous titania which was impregnated on HTiZFA existed as an amorphous phase. The specific surface area of HTiZFA (32.73–37.71 m2/g) did not alter a lot compared with that of ZFA, but the surface charge of HTiZFA (pH = 8.55) shifted to positive greatly, which caused a considerable enhancement in X‐3B adsorption. It was found that X‐3B sorption on HTiZFA was almost independent on initial pH because the removal rate maintained above 96% in a wide pH range of 3.0–11.0. An increasing qe with an upward temperature confirmed versatile attractive interactions and endothermic sorption nature, and a good ability was observed after several adsorption/desorption circulations. HTiZFA is expected to be a multifunctional adsorbent for treating higher concentration anionic pollutants that cannot be removed by commonly modified products efficiently.

Optimization of chitosan/tannic acid@ ZnFe layered double hydroxide bionanocomposite film for removal of reactive blue 4 using a response surface methodology

Layered double hydroxides (LDH) are great adsorbents for anionic pollutants, but are in a powder form that leads to challenges in solid-liquid separation, low hydraulic conductivity, and handling. Herein, novel bionanocomposite films containing chitosan (Cs), tannic acid (TA), and LDH were fabricated and applied for the removal of reactive blue 4 (RB4). A response surface methodology with Box–Behnken design was applied to study the effect of operating parameters (TA%: 0–20, LDH%: 0–20, pH: 5–9, adsorbent dosage: 0.5–1.5 g L−1, time: 30–90 min) on RB4 dye removal (DR%). A quadratic regression equation was successfully developed to predict the response (R2: 0.95). The obtained optimized condition was TA%: 10, LDH%: 20, pH: 5, adsorbent dosage: 1.5 g L−1, and time: 71 min that resulted in DR%: 98.2. The best-fitted adsorption isotherm and kinetic models were linear Langmuir and nonlinear pseudo-second-order models, respectively. The maximum capacity of adsorption for the optimized film was 406 mg g−1. The obtained thermodynamic parameters implied that the process of adsorption was exothermic and spontaneous. The reusability studies showed that the DR% was decreased from 93% for the first cycle to 69%, 57%, and 56% for the second, third and fourth cycle, respectively.

Poly(ionic liquids)-Impregnated UiO-66 composites for efficient sequestration of dichromate

Efficient sequestration of Cr(VI) pollutants from wastewater by metal-organic frameworks (MOFs) remains a great challenge, due to their poor stability and lack of rich anion-exchange sites. To enhance the uptake capacity, kinetics and recyclability of MOFs, a series of imidazolium-based ionic liquids (ILs) were encapsulated into the pores of UiO-66, and then via in situ cross-linking polymerization of ILs, to yield PILs/UiO-66 composites. Of great interest, these positive-charged polymers played the role of anion-exchange sites as inside filler and protective layers as outside coating of UiO-66. As a result, the top optimized composites exhibited outstanding stability (pH ​= ​0), fast sorption kinetics (within 1 ​min), superior uptake capacity (787 ​mg ​g−1, 5 times of UiO-66), high distribution coefficient (1.7 ​× ​105 ​mL ​g−1-, 4276 times of UiO-66), and good recyclability (>10 cycles), in the sequestration of dichromate from water solution. This established strategy provided a universal approach to promote the MOFs-based sorbents in sequestration of anion pollutants.

Correction: A Computational Study on Iron Oxide Magnetite Nanoparticles As Adsorbents of Anionic Pollutants

Correction: A Computational Study on Iron Oxide Magnetite Nanoparticles As Adsorbents of Anionic Pollutants

Bioinspired 3D Hierarchical UiO-66-NH2 Nanoparticle/γ-AlO(OH) Nanowire for Simultaneous Detection and Removal of Fluoride Ions

Excessive fluorine can cause a serious threat to human health. It is significant but challenging to develop a straightforward and rapid way to simultaneously detect and remove excess F– from water. Herein, we presented a three-dimensional (3D) hierarchical UiO-66-NH2 nanoparticle/γ-AlO(OH) nanowire hybrid synthesized by a facile biotemplate route for simultaneous detection and removal of F– from water. We elaborately assembled two kinds of materials in a bioinspired 3D hierarchical structure as a functional unit to achieve detection and removal of dual functions. The outer UiO-66-NH2 nanoparticles served as a fluorescent sensor to detect and capture F– via a strong fluorescence enhancement effect caused by the electron transfer from F– and γ-AlO(OH) and acted as the capture unit of F–. The inner γ-AlO(OH) nanowire layer served as a F– absorbent through ion exchange between F– and γ-AlO(OH). The resulting UiO-66-NH2 nanoparticle/γ-AlO(OH) nanowire hybrid displayed excellent selectivity and sensitivity for F– detection (the detection range was 0–5 mM and the limit of detection was as low as 0.77 μM) and high capacity for F– removal (the maximum equilibrium adsorption capacity qmax was as high as 87.0 mg g–1). This dual-function material provided a strategy for simultaneously selective sensing and efficient removal of anionic pollutants from water.

Improved SERS detection of anionic pollutant with Ag Nanoparticles-decorated ZnAl layered double hydroxide nanosheets array

Enrichment is a valuable strategy to further improve the detection limit. In this work, ZnAl-layered double hydroxide (ZnAl-LDH) nanosheets array in situ synthesized on Al foil was used as the enrichment frame for surface-enhanced Raman spectroscopy (SERS) substrate to further improve the detection limit of anionic pollutant. High density of Ag nanoparticles (Ag-NPs) with an average diameter of 29 nm sputtered onto the surface of the ZnAl-LDH could create localized electromagnetic field enhancement for SERS detection. The as-prepared Ag-NPs@ZnAl-LDH composite substrates showed improved sensitivity to anionic pollutants methyl orange and erythrosin B, demonstrating the promising potentials to improve the detection limit of anion analytes based on SERS spectroscopy.

Mechanochemical synthesis of bismuth-based anion exchange materials to immobilize arsenic pollution - Prospects for advanced treatment of anion-containing wastewater

Many types of anionic pollutants exit in the aqueous environment including the group containing halogen (F-, I-, IO3-, BrO3-, ClO3−), the group containing heavy metals (VO43−, AsO33−, CrO42−, AsO43−), and eutrophic elements resulting from agricultural, aquacultural, urban and industrial activities (NO3−, PO43−). Except for layered double hydroxide, anionic exchangeable resin, few choices are available to work for the treatment of the anionic pollutants. In this study, a new type of anion exchangeable compound was reported as an alternative. Sulfate-based layered bismuth oxide with the formula of Bi2O(OH)2SO4 as a clear crystalline phase was prepared simply by ball milling Bi oxide and sulfate together. Several analytical methods such as XRD, XPS, FTIR were used to characterize the products after the As (V) adsorption to understand the ions exchange mechanism. The excellent performance to fix arsenate anion reaching over 99.9% of As(V) removal percentage with Bi2O(OH)AsO4 as adsorption product was understood probably due to the synergistic effect of several exchangeable anions inside the prepared sample. This research may open a promising way to effectively remove toxic and harmful anions by the newly prepared anion exchangeable materials.

Synthesis of cationic biomass lignosulfonate hydrogel for the efficient adsorption of Cr(VI) in wastewater with low pH

ABSTRACT In the present study, we synthesized a cationic lignosulfonate hydrogel (LS-g-P (AM-co-DAC)) by grafting acrylamide (AM) and acryloxyethyl trimethyl ammonium chloride (DAC) onto sodium lignosulfonate (LS) via free radical copolymerization. The solution pH, contact time, initial concentration, and temperature were comprehensively investigated through the static adsorption method for the adsorption behaviours of Cr(VI) by the hydrogel. The experimental results show that the best conditions were a temperature of 30°C, a dosage of 0.1 g, pH = 3, a concentration of 50 mg / L, and contact time = 2 h with removal efficiencies of above 70% and adsorption capacity of 18.14 mg·g−1. The adsorption process followed the Langmuir isothermal model, indicating monolayer adsorption, and the maximum adsorption capacity was 58.86 mg·g−1. Adsorption kinetics results show that the pseudo-second-order kinetic model dominated the adsorption process, and the adsorption activation energy was 5.489 kJ·mol−1. In addition, the adsorption involved spontaneous exothermic and entropy reduction. The combination of FT-IR, SEM, and XRD was used to characterize the structure and properties of the prepared hydrogel, and the adsorption mechanism was the result of electrostatic attraction, physical and chemical adsorption, and hydrogen bond. The hydrogel has good regenerative properties after desorption. Overall, this work synthesized an environmentally friendly biomass lignin-based hydrogel, which can be used as an adsorbent for the treatment of anionic pollutants, and explored a new method for the high-value utilization of industrial lignin. Highlights Novel cationic lignosulfonate hydrogel (LS-g-P (AM-co-DAC)) was synthesized by a free radical method. SEM and XRD results confirmed the surface of the obtained hydrogel shows a 3D network structure and does not have a crystal structure. LS-g-P (AM-co-DAC) hydrogel adsorbent can selectively adsorb Cr6+ at pH 3.0. The adsorption conditions and the adsorption mechanism were studied in detail. Electrostatic interaction plays a key role in the adsorption of Cr6+.