Adsorption Properties For Metal Ions Research Articles

Multifunctional bacterial cellulose-bentonite@polyethylenimine composite membranes for enhanced water treatment: Sustainable dyes and metal ions adsorption and antibacterial properties

Developing multifunctional materials for water treatment remains a significant challenge. Bacterial cellulose (BC) holds immense potential as an adsorbent with high pollutant-binding capacity, hydrophilicity, and biosafety. In this study, N-acetylglucosamine was used as a carbon source to ferment BC, incorporating amide bonds in situ. Bentonite, renowned for its adsorption properties, was added to the culture medium, resulting in BC-bentonite composite membranes via a one-step fermentation process. Polyethyleneimine (PEI) was crosslinked with amide bonds on the membrane via glutaraldehyde through Schiff base reactions to enhance the performance of the composite membrane. The obtained membrane exhibited increased hydrophilicity, enhanced active adsorption sites, and enlarged specific surface area. It not only physically adsorbed contaminants through its unique structure but also effectively captured dye molecules (Congo red, Methylene blue, Malachite green) via electrostatic interactions. Additionally, it formed stable complexes with metal ions (Cd²⁺, Pb²⁺, Cu²⁺) through coordination and effectively adsorbed their mixtures. Moreover, the composite membrane demonstrated the broad-spectrum antibacterial activity, effectively inhibiting the growth of tested bacteria. This study introduces an innovative method for fabricating composite membranes as adsorbents for complex water pollutants, showing significant potential for long-term wastewater treatment of organic dyes, heavy metal ions, and pathogens.

Unlocking the potential of phenolated kraft lignin as a versatile feed additive

Lignin, a renewable natural antioxidant and bacteriostat, holds promise as a versatile, cost-effective feed additive. However, traditional industrial lignin faces limitations, including low reactivity, poor uniformity, and unstable properties, necessitating chemical modification. Complex modification methods pose economic and toxicity challenges, so this study adopted a relatively simple alkali-catalyzed phenolization approach, using phenol, catechol, and pyrogallol to modify kraft lignin, and characterized the resulting products using various techniques. Subsequently, their antioxidant, antibacterial, adsorption properties for heavy metal ions and mycotoxins, growth-promoting properties, and antiviral abilities were assessed. The phenolation process led to lignin depolymerization and a notable increase in phenolic hydroxyl content, particularly in pyrogallol-phenolated lignin (Py-L), rising from 3.08 to 4.68 mmol/g. These modified lignins exhibited enhanced antioxidant activity, with over 99 % inhibition against E. coli and S. aureus, and remarkable adsorption capacities for heavy metal ions and mycotoxins. Importantly, Py-L improved the growth performance of mice and reduced influenza mortality. Furthermore, density functional theory calculations elucidated the mechanism behind the enhanced antioxidant properties. This study presents a promising avenue for developing versatile feed additives to address challenges related to animal feed antioxidant supplementation, bacterial control, and growth promotion.

Effects of ZIF-L Morphology on PI@PDA@PEI/ZIF-L Composite Membrane's Adsorption and Separation Properties for Heavy Metal Ions.

Composite polymolecular separation membranes were prepared by combining multi-branched ZIF-L with high-porosity electrospinning nanofibers PI. Meanwhile, PDA and PEI were introduced into the membrane in order to improve its adhesion. The new membrane is called the "PI@PDA@PEI/ZIF-L-4" composite membrane. Compared with the PI@PDA@PEI/ZIF-8 composite membrane, the new membrane's filtration rates for heavy metal ions such as Cd2+, Cr3+, and Pb2+ were increased by 7.0%, 6.6%, and 9.3%, respectively. Furthermore, the new membrane has a permeability of up to 1140.0 L·m-2·h-1·bar-1, and displayed a very stable performance after four repeated uses. The separation mechanism of the PI@PDA@PEI/ZIF-L composite membrane was analyzed further in order to provide a basis to support the production of separation membranes with a high barrier rate and high flux.

Preparation of covalent organic framework with carboxy and triazine for efficient removal of Pb2+ ions

Recently, the development of high-selectivity porous materials has attracted much attention due to the long-term accumulation of heavy metals in the aquatic environment. Covalent organic frameworks (COFs) show great potential as sustainable porous materials, possessing several properties that make them suitable for sewage purification and rapid adsorption. In this paper, two novel COFs containing triazine and carboxyl bifunctional groups, DAA-TFPT-COF and PDA-TFPT-COF, were developed. The DAA-TFPT-COF and PDA-TFPT-COF have high specific surface areas and good metal ion adsorption properties. Moreover, they have behaved good metal ion adsorption ability in not only acidic but also alkaline environments, which is superior to ordinary adsorption materials. The maximum adsorption amount of the DAA-TFPT-COF was up to approximately 128 mg g−1 for Pb2+ ions. Additionally, the results of the simulation indicated that both COFs were consistent with the Langmuir adsorption model and the pseudo-second-order kinetic model, confirming the chemical adsorption process that occurs within the COFs. The strong adsorption effect in the COFs can be attributed to the electrostatic interactions between the COF and Pb2+ ions. This also shows that the active affinity sites in the system play a crucial role in the metal ion capture process. DAA-TFPT-COF has a high partition coefficient, and exhibited fast adsorption kinetics, which makes it an excellent candidate for metal ion adsorption.

Construction of carboxylated-GO and MOFs composites for efficient removal of heavy metal ions

Two-dimensional graphene oxide (GO) and metal–organic frameworks (MOFs) have great potential applications as high-performance adsorption materials. In this work, carboxylated-GO and MOFs have been successfully integrated to form nanocomposites (GO-COOH/MOF-808) with the combination of advantages of both and then demonstrated the excellent adsorption properties of heavy metal ions. The adsorption capacity of GO-COOH/MOF-808 and the influencing factors of the adsorption process are explored. The analysis shows that the adsorption equilibrium of heavy metal ions Pb(II), Cd(II), Co(II), Ni(II), and Cu(II) by GO-COOH/MOF-808 composites can be reached in 20 min under condition of the initial concentration of 100 mg/L and pH value of 5.5. Pb(II), Cd(II), Co(II), Ni(II), and Cu(II) have higher adsorption efficiencies, which are 157.78 mg/g, 135.96 mg/g, 82.35 mg/g, 90.99 mg/g, and 91.49 mg/g, respectively. Furthermore, the entire adsorption process followed the Langmuir isotherm model and the pseudo-second-order rate equation, suggesting that ion exchange and chemical adsorption are dominant. The synergistic effect of ion exchange, electrostatic adsorption, chemisorption, π-π interactions, and coordination complexation is attributed to the possible mechanisms of heavy metal ion adsorption. This research suggests that GO-COOH/MOF-808 is a promising and efficient adsorbent for heavy metal ion removal.

Synthesis of Crosslinked Poly(Vinylphosphonic Acid) Particles by Water-in-Oil (W/O) Suspension Polymerization Method and Their Adsorption Properties of Metal Ions

Crosslinked poly(vinylphosphonic acid) (PVPA) particles were successfully synthesized from vinylphosphonic acid and a crosslinker by water-in-oil (W/O) suspension polymerization using three silicone oils. The structure, morphology, and size of the PVPA particles were confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, and optical microscopy. The surface of the spherical particles was wrinkled, and their size ranged from 5 – 260 µm. The adsorption of divalent and trivalent metal ions (Cu2+, Zn2+, La3+, Tb3+, Lu3+) from aqueous solutions was studied using the synthesized PVPA particles under batch conditions at various metal ion concentrations and pHs for the first time. For all metal ions, pH-dependent adsorptions were observed. Partial charge neutralization of metal ions occurred because the PVPA particles are highly hydrophilic. The extraction efficiencies of La3+, Tb3+, and Lu3+ are higher than those of Cu2+ and Zn2+. The separation ability for La3+, Tb3+, and Lu3+ is not so high, but they can be used for the group extraction of these metal ions.

Research progress in the removal of heavy metals by modified chitosan

Abstract Chitosan and its modifiers have been widely studied for their good biocompatibility and excellent adsorption properties for heavy metal ions. The synthesis and application of modified chitosan, the effects of process variables (such as pH, amount of adsorbent, temperature, contact time, etc.), adsorption kinetics, thermodynamics and the adsorption mechanism on the removal of heavy metal ions are reviewed. The purpose is to provide the latest information about chitosan as adsorbent and to promote the synthesis of modified chitosan and its application in the removal of heavy metals.

Preparation of Functional Attapulgite Composite and Its Adsorption Behaviors for Congo Red

Heavy metal ion wastewater poses a serious threat to human health and the environment. The adsorption method is an important method to remove heavy metal ions from heavy metal wastewater. Magnetic attapulgite (ATP) composite nanomaterials with excellent adsorption properties were prepared by grafting the Fe3O4 nanoparticles and using 3-aminopropyl triethoxy silane (APTES) modification. The prepared ATP-Fe3O4-APTES materials were used as adsorbents and applied to the treatment of heavy metal ion wastewater. The structure and surface properties of the materials were characterized by FT-IR, XRD, SEM, TEM, and BET characterization, Zeta potential, and VSM. The effects of pH, adsorption time, adsorption temperature, and initial concentration of Pb2+ on the adsorption properties of the ATP-Fe3O4-PEI materials were investigated. The results show that the maximum adsorption capacity of the materials for Pb2+ was 129.32 mg·g-1 under optimum conditions. The adsorption process conformed to the pseudo second order kinetic model and Langmuir adsorption isotherm, which indicates that the adsorption of Pb2+ is a monolayer chemical adsorption and a spontaneous endothermic process. The driving force of adsorption mainly comes from the coordination between the amino group (-NH2) on the ATP-Fe3O4-APTES surface and Pb2+. These results indicate that the functionalized magnetic attapulgite adsorbent has good adsorption properties for heavy metal ions and is expected to be used in the treatment of heavy metal ion wastewater.

Polyvinyl Alcohol Polymer Functionalized Graphene Oxide Decorated with Gadolinium Oxide for Sequestration of Radionuclides from Aqueous Medium: Characterization, Mechanism, and Environmental Feasibility Studies.

Uranium (U(VI)) and thorium (Th(IV)) ions produced by the nuclear and mining industries cause water pollution, thereby harming the environment and human health. In this study, gadolinium oxide-decorated polyvinyl alcohol-graphene oxide composite (PGO–Gd) was developed using a simple hydrothermal process to treat U(VI) and Th(IV) ions in water. The developed material was structurally characterized by highly advanced spectroscopy and microscopy techniques. The effects of pH, equilibration time and temperature on both radionuclides (U(VI) and Th(IV)) adsorption by PGO–Gd were examined. The PGO–Gd composite adsorbed both metal ions satisfactorily, with adsorption capacities of 427.50 and 455.0 mg g−1 at pH 4.0, respectively. The adsorption properties of both metal ions were found to be compatible with the Langmuir and pseudo–second-order kinetic models. Additionally, based on the thermodynamic characteristics, the adsorption was endothermic and spontaneous. Furthermore, the environmental viability of PGO–Gd and its application was demonstrated by studying its reusability in treating spiked surface water. PGO–Gd shows promise as an adsorbent in effectively removing both radionuclides from aqueous solutions.

Preparation and adsorption performance of cellulose nanofibrils/polyvinyl alcohol composite gel spheres with millimeter size

Wastewater treatment is a huge problem facing human beings. The development of recyclable and efficient adsorption materials is of great benefit to solve the problem. Based on the biodegradable cellulose nanofibers (CNFs) derived from biomass resources, the large sized CNFs/PVA composite hydrogel spheres (CV-HSs, 1–3 mm) were successfully prepared by the inverse suspension pellet-forming technology using the polymers as raw materials, and another hydrophobic CNFs/PVA composite aerogel spheres (HCV-ASs) were also obtained by lyophilization and followed silylation of as-prepared CV-HSs. The CV-HSs showed excellent adsorption properties for simulated pollutants, including Cu2+, phenol and aniline in water. The maximum absorption capacity of CV-HSs was 17.22 mmol/g for Cu2+, 176.72 mg/g for phenol and 341.93 mg/g for aniline respectively. The HCV-ASs exhibited good absorption properties for weak polar organic solvents, such as petroleum ether, ethyl acetate and toluene. In summary, two kinds of large-sized CNFs/PVA composite gel spheres were successfully fabricated, and exhibited good adsorption properties for organic pollutants and heavy metal ions, indicating their potential for wastewater treatment.

Modified graphene oxide composite aerogels for enhanced adsorption behavior to heavy metal ions

Exploiting adsorbents with high adsorption activity, good durability and low cost is still the core focus of water pollution treatment. In this study, sodium alginate (SA), graphene oxide (GO), and β-cyclodextrin (βCD) were used as raw materials to frame a composite aerogel with an orderly 3D network structure by a sol-gel and freeze-drying method. The incorporation of (graphene oxide)-β-cyclodextrin (GO-βCD) could make SA molecules have higher cohesion and create more active sites for adsorbates. The temperate ratio of GO-βCD and SA to be integrated was also discussed in this work. When GO-βCD was 4 wt% (i.e., SA/GO-βCD-4), the compress performance of the composite aerogel could be 37.97% higher than the original pure SA aerogel, and the saturated adsorption capacity for Cu2+ and Cd2+ reached up 148.49 and 174.85 mg/g. It shows that SA/GO-βCD-4 composite aerogels have excellent adsorption properties for metal ions. The test data was fitted to reveal the adsorption mechanism. The adsorption kinetics of the pseudo-second-order kinetic model and Langmuir isotherm models were identified to coincide with the adsorption behavior of the modified aerogel. Comprehensively, the synthesis of the samples could pave a new way for versatile adsorbents.

Preparation of Chitosan/Calcium Alginate/Bentonite Composite Hydrogel and Its Heavy Metal Ions Adsorption Properties.

In order to avoid the secondary pollution of the toxic residue of chemical crosslinking agent accompanied by chemical hydrogel adsorbent and enhance the adsorption performance of physical hydrogel, chitosan/calcium alginate/bentonite (CTS/CA/BT) composite physical hydrogel was constructed. The formation mechanism and structure of the composite hydrogel were determined by FTIR, XRD and SEM. Adsorption performances of the hydrogel toward Pb2+, Cu2+ and Cd2+ in water under different condition as well as multi-ion competitive sorption were investigated. The adsorption processes were described with the canonical adsorption kinetics and isotherms models. With the utilization of XPS analysis and adsorption thermodynamics analysis, it was found that the adsorptions were spontaneous physico-chemical adsorptions. The results showed that the maximum adsorption capacity of the hydrogel for Pb2+, Cu2+ and Cd2+ reached up to 434.89, 115.30 and 102.38 mg·g−1, respectively, better than those of other physical hydrogels or chitosan/bentonite composite. Moreover, the composite hydrogel improved the collectability of bentonite and showed a good reusability. The modification of bentonite and the formation of hydrogel were completed simultaneously, which greatly simplifies the operation process compared with the prior similar works. These suggest that the CTS/CA/BT composite hydrogel has promising application prospects for removal of heavy metal ions from water.

Development of a novel cathodic deposition method for thin-film metal azolate frameworks toward Cd2+ adsorption

Metal-Organic Frameworks (MOFs) have attracted much attention due to its large specific surface, flexible porosity and unsaturated coordination bonds. Cathodic deposition is a unique in-situ potential-driven synthesis method for the deposition of thin film MOFs; however, the gradually consumption of reactants during cathodic deposition might lead to unstable and uncontrollable reaction during thin-film MOF deposition. Herein, oxygen is selected as the initial reactant for the formation of OH−, which can result in gradually and successive formation of thin-film MAF-66 (Metal azolate framework-66), and the particle size and film thickness of the MAF-66 film can be easily tuned by the deposition time. Furthermore, the cathodic deposited thin-film MAF-66 show good adsorption property for heavy metal ions, with Cd2+ as a representative species. The adsorption capacity can reach 32.3 ​mg/g (removal ratio: 69%) and the deposited MAF-66 film can achieve a satisfactory recovery degree with structural and morphological stability. In this way, a novel, environmental-friendly, and controllable cathode deposition method is developed for preparation of thin-film MAF-66, which also show great promise as a candidate for heavy metal ions adsorbent.

Syntheses, characterization, and adsorption properties for metal ions of silica-gel functionalized by poly[8-methacroyloxy-quinoline

By mean of heterophase polymerization on the silica gel surface has been made in situ immobilization of poly [8-methacroyloxy-quinoline], has been received new organic-mineral composite material. Infrared and mass spectroscopy as well as termogravimetry (TG) analysis have been used to elucidate the structure of immobilized polymer. An adsorption capacity of the synthesized composite toward Cu(ІІ), Pb(ІІ), Mn(ІІ), Fe(ІІІ), Cd(ІІ) ions has been estimated. Adsorption activity to microquantities of Cu(ІІ), Mn(ІІ), Fe(ІІІ), Cd(ІІ) in a neutral aqueous medium has been observed.

A silsesquioxane-porphyrin-based porous organic polymer as a highly efficient and recyclable absorbent for wastewater treatment

Effective capture of pollutants from wastewater is crucial for protecting the environment and human health. An azo-based porous organic polymer (AzoPPOP) containing porphyrin and inorganics cage polyhedral oligomeric silsesquioxane units was synthesized via a catalyst-free coupling reaction. Results showed that AzoPPOP possess a high surface area, a hierarchically porous structure, good thermal stability, abundant adsorption sites, and an electronegative nature. Based on these properties, AzoPPOP had an extremely high adsorption capacity (1357.58 mg g−1) for RhB, a fast adsorption rate, and good selectivity. Study of the mechanism revealed that in addition to electrostatic interactions, the high specific surface area, existence of -NH2, and the strong π-π interaction between AzoPPOP and RhB also play important roles for the adsorption of RhB. AzoPPOP also displayed excellent adsorption properties for heavy metal ions (230.45, 192.24 and 162.11 mg g−1 for Ag+, Hg2+, and Pb2+, respectively). More importantly, simulation of the purification experiment of waste water and the recycling regeneration experiment revealed that AzoPPOP has good high-level recyclability and could remove multi-pollutants in one pass through a simple adsorption column.

Bio-Template Synthesis of Strontium Titanate and Application for Heavy Metal Adsorption in Wastewater

Heavy metal ions, such as chromium, cadmium, mercury, nickel, copper, and zinc, cause severe pollution to water bodies as well as enormous harm to people and the biosphere. Adsorption and removal of heavy metal pollution in water is a low-cost and straightforward method. Researchers are currently looking for materials that are cheap and readily available, and have high adsorption and enrichment properties for heavy metal ions. Strontium titanate is a new type of ceramic material, and there have been few related research reports. The work reported a new method for the synthesis of strontium titanate adsorbent by the sol-gel biotemplate method. A sol-gel method, using different types of straws as biological templates, was selected to prepare nano-strontium titanate adsorption materials. In this experiment, chelate formed using tetra-n-butyl titanate and strontium nitrate as raw materials, and acetic acid as a chelating agent, thereby forming a sol. Then, corn straw and sunflower straw immersed in the sol and aged for a period. After drying and calcination, a strontium titanate adsorbent with a biofilm microstructure was obtained. Besides, the structure of strontium titanate synthesized was characterized by SEM and XRD. In this experiment, zinc ions were used as adsorbed ions to investigate the adsorption capacity of the synthesized strontium titanate adsorbents for heavy metal ions in water. Studies have shown that strontium titanate synthesized by the biological template method was a porous material retaining some of the natural tissue structure characteristics of the biological template. Compared with the strontium titanate obtained without using the biological template, the adsorption capacity of the strontium titanate powder synthesized by the biological template method to zinc ion was significantly improved. We studied the influence of the selection and adsorption of biological templates and pH conditions on the ability of strontium titanate to adsorb zinc ions.

Preparation of a Novel Polystyrene-Poly(hydroxamic Acid) Copolymer and Its Adsorption Properties for Rare Earth Metal Ions.

In this study, a novel polystyrene-poly(hydroxamic acid) copolymer was synthesized as an effective adsorbent for the treatment of rare earth elements. Through the use of elemental analysis as well as FTIR, SEM, XPS, and Brunauer-Emmett-Teller (BET) surface area measurement, the synthesized polymer was found to have a specific surface area of 111.4 m2·g−1. The adsorption performances of rare metal ions were investigated under different pH levels, contact times, initial concentrations of rare earth ions, and temperatures. The adsorption equilibrium for La3+, Ce3+, and Y3+ onto a polystyrene-poly(hydroxamic acid) copolymer is described by the Langmuir model, which confirms the applicability of monolayer coverage of rare earth ions onto a polystyrene-poly(hydroxamic acid) copolymer. The amount of adsorption capacities for La3+, Ce3+, and Y3+ reached 1.27, 1.53, and 1.83 mmol·g−1 within four hours, respectively. The adsorption process was controlled by liquid film diffusion, particle diffusion, and chemical reaction simultaneously. The thermodynamic parameters, including the change of Gibbs free energy (∆G), the change of enthalpy (∆H), and the change of entropy (∆S), were determined. The results indicate that the adsorption of resins for La3+, Ce3+ and Y3+ was spontaneous and endothermic. The polymer was also used as a recyclable adsorbent by the desorption experiment.

Facile preparation of multiphosphonic acid functionalised multi‐walled carbon nanotubes for enhanced adsorption properties for heavy metal ions from wastewaters

This work presents facile preparation processes of multiphosphonic acid functionalised multi-walled carbon nanotubes (HEDP-MWCNTs and ATMP-MWCNTs), which have been characterised by FT-IR, XPS, X-ray diffraction, TGA, and SEM, and have employed for heavy metal ions adsorption. The adsorption properties of MWCNTs, HEDP-MWCNTs, and ATMP-MWCNTs for gold ions, cadmium ions, copper ions, lead ions, nickel ions, cobalt ions, zinc ions, and chromium ions have been investigated, the experimental results reveal that the functionalised samples HEDP-MWCNTs and ATMP-MWCNTs have excellent adsorption properties for Pb(II) and Au(III), respectively. The investigation results on their adsorption selectivity represent that in the binary heavy metal ion systems, HEDP-MWCNTs/ATMP-MWCNTs has displayed a strong affinity for Pb(II)/Au(III) and even could exhibit 100% selectivity while coexisting with copper ions, nickel ions, cobalt ions, zinc ions, chromium ions, or cadmium ions. Furthermore, the adsorption kinetics of HEDP-MWCNTs for Pb(II) and ATMP-MWCNTs for Au(III) have also been studied at different solution temperatures. All these research work results show that two novel functionalised adsorbents HEDP-MWCNTs and ATMP-MWCNTs have shown excellent adsorption properties for heavy metal ions and they can be used in wastewater treatment, especially for lead/gold ions removal.

First-principles calculations of stability of graphene-like BC3 monolayer and its high-performance potassium storage

With increasing demand for renewable energy, graphene-like BC3 monolayer as high performance electrode materials for lithium and sodium batteries are drawing more attention recently. However, its structural stability, potassium storage properties and strain effect on adsorption properties of alkali metal ions have not been reported yet. In this work, phonon spectra, AIMD simulations and elastic constants of graphene-like BC3 monolayer are investigated. Our results show that graphene-like BC3 monolayer possesses excellent structural stability and the maximum theoretical potassium storage capacity can reach up to 1653mAh/g with the corresponding open circuit voltages 0.66V. Due to potassium atom can be effectively adsorbed at the most energetically favorable h−CC site with obvious charge transfer, making adsorbed graphene-like BC3 monolayer change from semiconductor to metal which is really good for electrode utilization. Moreover, the migrations potassium atom on the graphene-like BC3 monolayer is rather fast with the diffusion barriers as low as 0.12eV, comparing lithium atom with a relatively large diffusion barrier of 0.46eV. Additionally, the tensile strains applied on the graphene-like BC3 monolayer have marginal effect on the adsorption and diffusion performances of lithium, sodium and potassium atoms.

Preparation of graphene oxide/chitosan complex and its adsorption properties for heavy metal ions

AbstractGraphene oxide hydrosol was added dropwise to the surface of chitosan (CS) to successfully obtain graphene oxide/chitosan composite (GC). The composite material was characterized by scanning electron microscopy and X-ray diffraction. The prepared adsorbent was used to simulate the static adsorption of copper, lead, and cadmium ions from 100 mL of 50 mg/L simulated wastewater samples. When the pH of the simulated wastewater is 6, initial dosage is 70 mg, adsorption time is 90 min, and temperature is 20°C; the adsorption capacities for copper, lead, and cadmium are 60.7, 48.7, and 32.3 mg/g, respectively. The adsorption and desorption cycle experiments show that the adsorption capacity of GC for copper ions can reach 86% of the initial adsorption capacity after ten cycles. The adsorption of lead ions on the composite conforms to the Freundlich adsorption isotherm model.