Adsorption Of Divalent Metal Ions Research Articles

Origin for superior adsorption of metal ions and efficient control of heavy metals by montmorillonite: A molecular dynamics exploration

Ion adsorption/exchange at charged solid/water interfaces plays a central role during a broad spectrum of chemical, environmental and engineered processes. Almost all clay minerals are featured by strong charge heterogeneity (ChHg), and in this study, critical importance and regulatory mechanisms of ChHg during adsorption/exchange of metal ions and control of heavy metals at montmorillonite interfaces have been unraveled. Although increase of charge densities promotes adsorption of metal ions, inner-sphere (InS) Pb2+ appears only at very high charge densities (1.50 e/uc); In contrast, ChHg causes considerable InS(Pb2+) at 0.75 e/uc. Compared to InS(Ca2+), InS(Pb2+) emerges at much lower ChHg: 0.03 vs. 0.11 C/m2, and is apparently superior regarding both amount and stability; Moreover, stronger ChHg further promotes InS adsorption; e.g., at 0.11 C/m2, InS(Pb2+) and InS(Ca2+) have adsorption densities of 0.34 and 0.06 μmol/m2 and potential energies of -121.3 and -81.5 kJ/mol, respectively. Pb2+ dominates InS adsorption of binary Pb2+/Ca2+ systems, and impacts of co-ions are consistent for all ChHg and magnified at stronger ChHg: Pb2+ always suppresses Ca2+ adsorption whereas Ca2+ always promotes Pb2+ adsorption. Selectivity coefficients amount to 0.87, 1.06 and 1.16 when ChHg equals 0.00, 0.05 and 0.11 C/m2, respectively. Increase of ChHg causes the switch from Ca2+-selectivity to Pb2+-selectivity, and adds kinetic difficulty of Pb2+ exchange by Ca2+. Accordingly, ChHg within montmorillonite becomes source for efficient adsorption of divalent metal ions and control of heavy metals. Results rationalize experimental observations at molecular level, and provide new insights about adsorption/exchange of metal ions and control of heavy metals at clay/water interfaces that are significantly beneficial to screening and synthesis of efficient clay-based adsorbents.

Kinetika adsorpcije dvovalentnih metala na aminofunkcionalizovanom ugljeničnom nanomaterijalu

The subject of this study was to investigate the adsorption behavior of selected divalent metals (Cu (II), Cd (II), Pb (II)) on amino-functionalized multiwalled carbon nanotubes, MWCNT-NH2, at four selected pH values (3; 4.5, 6, 11), in order to estimate the possibility of using MWCNT-NH2 to remove ion metal from aqueous solutions at relatively low concentrations (0.01-0.1 mg L-1). The focus of the study was to determine the adsorption mechanism at the experimental conditions. The adsorption of divalent metal ions on MWCNT-NH2 was best described by the pseudo-second order kinetics model, which indicates that adsorption can be attributed to the chemical interactions between the adsorbates and the binding groups on the surface of the adsorbent. Modeling the adsorption rate by the Weber-Morris diffusion model indicated that intra-particle diffusion, although a slower step than external diffusion, is not the only limiting step in the adsorption process, and that the interaction of the investigated ions with the binding sites on the adsorbent surface also control the adsorption rate. Assessment of the impact of pH on the adsorption rate has shown that the pH value, in the investigated range, has the highest effect on the adsorption efficiency of Cu (II) and the lowest for the removal of Cd (II).

The Adsorption of Divalent Metal Ions from Aqueous Media Using Unmodified Orange Peel (Musa sapientum) as Adsorbent

Water is one of the world’s most valuable resources, which is under constant threat due to climate change, drought, explosive population growth and waste. A wide variety of heavy metal species enters the aquatic compartment through atmospheric deposition, lixiviation of mining areas and cultivated fields, and industrial discharges. These activities follow an upward curve in response to the world’s ever growing population and its needs. Therefore, there is need to discover non-toxic adsorbent from natural source to combat the menace of water pollution. Orange peel is a non-toxic and environmentally friendly fruit, adsorbent potentials. The present study investigates the adsorption of divalent metal ions from aqueous media using unmodified orange peel as adsorbent. The orange peels for the adsorption experiment was cut, washed, dried and ground into fine powder. The powdered material was characterized using Fourier Transform Infrared (FT-IR) spectrophotometer and Scanning Electron Microscope (SEM). Determination of heavy metals adsorbed was performed on Perkin Elmer model 214 Atomic Absorption Spectrometry (AAS). The effect of pH, contact time, initial metal ion concentration and adsorbent dosage in the removal of heavy metals from aqueous media were evaluated. The Orange peel showed high metal uptake for the tested metal ions Co2+ (97.8%), Cu2+ (95.5%) and Zn2+ (97.0%). The optimum pH for Orange peel was 3, the optimum contact time for the dehydration method of the orange peel was 150 min, and the optimum adsorbent dosage for the Orange peel was 2 g while the orange peel biosorbent optimum initial metal ion concentration was 40 ppm. Adsorption data fitted well with Freundlich and Langmuir equilibrium adsorption isotherms. The maximum adsorption capacity Q value for Langmuir model for the initial metal ion concentration were in the order Cu2+>Co2+>Zn2+. Conclusively, the effective adsorbent properties displayed by the orange peels in the removal of divalent ion from aqueous media studies indicate their potentials in the treatment of water pollution.

Graphene oxide/cellulose membranes in adsorption of divalent metal ions

In this paper, graphene oxide/cellulose membranes were prepared in order to perform effective adsorption of heavy metal ions: cobalt, nickel, copper, zinc, cadmium and lead.

Second-order kinetic model for the adsorption of divalent metal ions on Sida acuta leaves

The removal of metal ions from effluents is of importance to many countries of the world both environmentally and for water re-use. A comparison was made of the linear least-squares method of the widely used pseudo-second order kinetic model for the sorption of some divalent metal ions onto Sida acuta leaves. Four pseudo-second order kinetic linear equations were used for this study. The results obtained from the experimental data for S. acuta leaves of 1.0 g with particle size range of 0.25 to 0.5 mm and at 300 rpm with initial concentrations of 5.0, 4.0, 20 and 2.5 mg/dm3 for Cu2+, Ni2+, Pb2+ and Zn2+ ions, respectively showed that when the four pseudo-second order kinetic linear equations were compared, the Type 2 model with regression values for Cu2+, Ni2+, Pb2+ and Zn2+ ions as 0.979, 0.995, 0.991 and 0.965 respectively showed best fit for the sorption onto S. acutaleaves. This provided the evidence that the divalent metal ions sorption unto S. acutafollowed the pseudo-second – order kinetic expression. Key words: Sida acuta, sorption, divalent metal ions, kinetic model, effluents .

Adsorption of divalent metal ions from aqueous solutions using graphene oxide

The adsorptive properties of graphene oxide (GO) towards divalent metal ions (copper, zinc, cadmium and lead) were investigated. GO prepared through the oxidation of graphite using potassium dichromate was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FT-IR). The results of batch experiments and measurements by flame atomic absorption spectrometry (F-AAS) indicate that maximum adsorption can be achieved in broad pH ranges: 3-7 for Cu(II), 5-8 for Zn(II), 4-8 for Cd(II), 3-7 for Pb(II). The maximum adsorption capacities of Cu(II), Zn(II), Cd(II) and Pb(II) on GO at pH = 5 are 294, 345, 530, 1119 mg g(-1), respectively. The competitive adsorption experiments showed the affinity in the order of Pb(II) > Cu(II) ≫ Cd(II) > Zn(II). Adsorption isotherms and kinetic studies suggest that sorption of metal ions on GO nanosheets is monolayer coverage and adsorption is controlled by chemical adsorption involving the strong surface complexation of metal ions with the oxygen-containing groups on the surface of GO. Chemisorption was confirmed by XPS (binding energy and shape of O1s and C1s peaks) of GO with adsorbed metal ions. The adsorption experiments show that the dispersibility of GO in water changes remarkably after complexation of metal ions. After adsorption, the tendency to agglomerate and precipitate is observed. Excellent dispersibility of GO and strong tendency of GO-Me(II) to precipitate open the path to removal of heavy metals from water solution. Potential application of GO in analytical chemistry as a solid sorbent for preconcentration of trace elements and in heavy metal ion pollution cleanup results from its maximum adsorption capacities that are much higher than those of any of the currently reported sorbents.

Particle concentration effect: Adsorption of divalent metal ions on coffee grounds

The adsorption of divalent metal ions Cu 2+, Pb 2+, Zn 2+, and Cd 2+ on coffee grounds as a function of coffee grounds concentration was studied in which adsorption density decreased as the concentration of coffee grounds ( C s) increased. Adsorption studies were conducted by equilibrating aqueous solutions of each metal ion at concentrations in the range 19–291 μmol L −1 with coffee suspensions in the concentration range 0.971–8.738 g L −1, with the initial pH adjusted to 5.0 ± 0.1 using NaOH or HNO 3. Metastable Equilibrium Adsorption theory did not adequately explain the adsorption phenomenon, except at low concentrations of coffee grounds and trace metal ions. Instead the results indicated that flocculation might reduce the surface availability thus reducing the adsorption density. The flocculation theory was confirmed after a further experiment adding dispersant sodium hexa-meta-phosphate (NaHMP) to the suspension.

Synthesis and Characterization of Phosphonate Ester/Phosphonic Acid Grafted Styrene−Divinylbenzene Copolymer Microbeads and Their Utility in Adsorption of Divalent Metal Ions in Aqueous Solutions

In this paper the preparation and characterization of some chelating resins, phosphonate grafted on polystyrene−divinylbenzene supports, are reported. The resins were prepared by an Arbuzov-type reaction between chloromethyl polystyrene−divinylbenzene copolymers and triethylphosphite, yielding the phosphonate ester copolymer (resin A). This can be hydrolyzed by HCl to yield the phosphonate/phosphonic acid copolymer (resin B). The phosphonate resins A and B were characterized by determination of the phosphorus content, infrared spectrometry, and thermal analysis. The total sorption capacity of the phosphonate ester functionalized resin (A) and phosphonate/phosphonic acid functionalized resin (B) for divalent metal ions such as Ca2+, Cu2+, and Ni2+ was studied in aqueous solutions. Resin A retains ∼3.25 mg of Ca2+/g of copolymer and 2.75 mg of Cu2+/g of copolymer, but retains no Ni2+ at pH 1. On the other hand, resin B retains 8.46 mg of Ca2+/g of copolymer, 7.17 mg of Cu2+/g of copolymer, and no Ni2+ at pH 1. Efficient Ni2+ retention was observed at pH 7 only for the phosphonate/phosphonic acid functionalized resin (B) at the level of 19 mg of Ni2+/g of polymer B. Polymer A was incapable of retaining Ni2+ at pH 7.

Preparation of alginate–chitosan hybrid gel beads and adsorption of divalent metal ions

Naturally occurring polysaccharides such as alginic acid and chitosan have been recognized as one of the most effective adsorbents to eliminating low levels of heavy metal ions from waste water stream. The present study intended to use alginic acid and chitosan simultaneously, which are expected to form a rigid matrix structure of beads due to electrostatic interaction between carboxyl groups on alginic acid and amino groups on chitosan, and to prepare alginate–chitosan hybrid gel beads. This could be achieved for the first time by using water-soluble chitosan, which was obtained by deacetylating chitin to 36–39% degree. The water-soluble chitosan dissolved in water could remain in solution in the presence of sodium alginate, and the homogeneous solution of chitosan and alginate was dispensed into a CuCl 2 solution to give gel bead particles. The resultant beads were then reinforced by a cross-linking reaction of aldehyde groups on glutaraldehyde with amine groups on the chitosan. The cross-linking reaction made the beads durable under acidic conditions. The adsorption of Cu(II), Co(II), and Cd(II) on the beads was significantly rapid and reached at equilibrium within 10 min at 25 °C. Adsorption isotherms of the metal ions on the beads exhibited Freundlich and/or Langmuir behavior, contrary to gel beads either of alginate or chitosan showing a step-wise shape of adsorption isotherm.

Direct evidence for two interaction modes in adsorption of divalent metal ions to iminodiacetate-type chelating resins.

The adsorption curves of divalent metal ions (M2+) to an iminodiacetate(IDA)-type chelating resin (-L2-) under the condition of metal ions in excess against IDA groups clearly indicated the difference in contribution between two species. Copper and nickel are adsorbed only as [(-L)M(II)], while cadmium and calcium are adsorbed as [(-L)M(II)] and [(-LH)2M(II)]. Addition of salts may enhance the deprotonation of IDA groups, interfere with the adsorption as [(-LH)2M(II)], and yield remarkable changes in adsorption curves, depending on the metal ions.

Adsorption of divalent metal ions by succinylated and oxidized corn starches

Corn starch was succinylated (degree of substitution, DS 0.03–0.07) with succinic anhydride in an aqueous alkaline medium (pH 10), or oxidized (DS 0.13–0.29) with sodium hypochlorite in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) and sodium bromide, and the adsorption properties of the starches for Cu 2+, Zn 2+, Pb 2+, and Cd 2+ in their aqueous salt solutions were investigated under various conditions. Regardless of the metal type, the adsorption capacity of both ionic starches reached a state of equilibrium within 5–10 min for starch dispersion in metal solutions. The succinylated starch was most effective in binding Pb 2+, whereas the oxidized starch was effective for Cu 2+ among the tested metal ions. Cd 2+ was least effective in binding either to the succinylated or to the oxidized starch. However, the oxidized starch was partially soluble in aqueous solutions, and thus the starch dissolution resulted in reduced metal-adsorption efficiency. The metal-adsorption of both ionic starches followed the Langmuir adsorption isotherm. The maximum adsorption capacity ( Q) and Langmuir constant ( b) for a succinylated starch (DS 0.07) for Pb 2+ were 0.534 mmol g −1 and 2.276×10 −3 ppm −1, respectively. These values were higher than those of Cu 2+, Zn 2+, and Cd 2+. The Q and b values for an oxidized starch (DS 0.29) for Cu 2+ were significantly higher (1.245 mmol g −1 and 14.98×10 −3 ppm −1, respectively) than those of Pb 2+, Zn 2+, and Cd 2+. Therefore, among the tested ions, Pb 2+ was adsorbed most effectively by the succinylated starch, and Cu 2+ by the oxidized starch.

The role of electrolyte anions (ClO 4 (super -) , NO 3 (super -) , and Cl (super -) ) in divalent metal (M (super 2+) ) adsorption on oxide and hydroxide surfaces in salt solutions

Adsorption of divalent metal ions (M{sup 2+}) onto oxide and hydroxide surfaces from solutions of strong electrolytes has typically been inferred to take place without the involvement of the electrolyte anion. Only in situations where M{sup 2+} forms a strong enough aqueous complex with the electrolyte anion (for example, CdCl{sup +} or PbCl{sup +}) has it been frequently suggested that the metal and the electrolyte anion adsorb simultaneously. A review of experimental data for the adsorption of Cd{sup 2+}, Pb{sup 2+}, Co{sup 2+}, UO{sub 2}{sup 2+}, Zn{sup 2+}, Cu{sup 2+}, Ba{sup 2+}, Sr{sup 2+}, and Ca{sup 2+} onto quartz, silica, goethite, hydrous ferric oxide, corundum, {gamma}-alumina, anatase, birnessite, and magnetite, from NaNO{sub 3}, KNO{sub 3}, NaCl, and NaClO{sub 4} solutions over a wide range of ionic strengths (0.0001 M-1.0 M), reveals that transition and heavy metal adsorption behavior with ionic strength is a function of the type of electrolyte. In NaNO{sub 3} solutions, metal adsorption exhibits little or no dependence on the ionic strength of the solution. However, in NaCl solutions, transition and heavy metal adsorption decreases strongly with increasing ionic strength. In NaClO{sub 4} solutions, metal adsorption decreases strongly with increasing ionic strength. In NaClO{sub 4} solutions, metal adsorptionmore » exhibits little dependence on ionic strength but is often suggestive of an increase in metal adsorption with increasing ionic strength. Analysis of selected adsorption edges was carried out using the extended triple-layer model and aqueous speciation models that included metal-nitrate, metal-chloride, and metal-hydroxide complexes.« less

Comment on “Nonreversible Adsorption of Divalent Metal Ions (MnII, CoII, NiII, CuII, and PbII) onto Goethite: Effects of Acidification, FeII Addition, and Picolinic Acid Addition”

ADVERTISEMENT RETURN TO ISSUEPREVCorrespondence/Rebut...Correspondence/RebuttalNEXTComment on “Nonreversible Adsorption of Divalent Metal Ions (MnII, CoII, NiII, CuII, and PbII) onto Goethite: Effects of Acidification, FeII Addition, and Picolinic Acid Addition”Colin G. Ong and James O. LeckieView Author Information Department of Civil Engineering Stanford University Stanford, California 94305Cite this: Environ. Sci. Technol. 1996, 30, 4, 1411Publication Date (Web):March 26, 1996Publication History Published online26 March 1996Published inissue 1 March 1996https://doi.org/10.1021/es950835nCopyright © 1996 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views194Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (89 KB) Get e-AlertsSUBJECTS:Adsorption,Mathematical methods,Multicomponent reactions,Sorption,Theoretical and computational chemistry Get e-Alerts

Response to Comment on “Nonreversible Adsorption of Divalent Metal Ions (MnII, CoII, NiII, CuII, and PbII) onto Goethite: Effects of Acidification, FeII Addition, and Picolinic Acid Addition”

ADVERTISEMENT RETURN TO ISSUEPREVCorrespondence/Rebut...Correspondence/RebuttalResponse to Comment on “Nonreversible Adsorption of Divalent Metal Ions (MnII, CoII, NiII, CuII, and PbII) onto Goethite: Effects of Acidification, FeII Addition, and Picolinic Acid Addition”Alan T. Stone and Barbara R. CoughlinView Author Information Department of Geography and Environmental Engineering G. W. C. Whiting School of Engineering The Johns Hopkins University Baltimore, Maryland 21218Cite this: Environ. Sci. Technol. 1996, 30, 4, 1412Publication Date (Web):March 26, 1996Publication History Published online26 March 1996Published inissue 1 March 1996https://doi.org/10.1021/es9510119Copyright © 1996 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views252Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (117 KB) Get e-AlertsSUBJECTS:Adsorption,Ions,Nuclear magnetic resonance spectroscopy,pH Get e-Alerts

Nonreversible Adsorption of Divalent Metal Ions (MnII, CoII, NiII, CuII, and PbII) onto Goethite: Effects of Acidification, FeII Addition, and Picolinic Acid Addition

Differences in the coordination chemistry of divalent metal ions affect their adsorption onto goethite (a-FeOOH) surfaces and their subsequent release by acidification, Fe II addition, and picolinic acid addition. Equilibrium constants for adsorption onto FeOOH (goethite) decrease in the order : Cu II > Pb II > Ni II Co II > Mn II . Equilibrium constants for picolinic acid complexation follow the Irving-Williams series ; complex formation with Pb II and Mn II is nearly negligible. Divalent metal ion release 24 h following acidification or picolinic acid addition is typically less than the amount predicted using an equilibrium speciation model, indicating adsorption/desorption hysteresis. Experiments performed under strict exclusion of O 2 reveal a slight increase in Co II , Ni II , and Cu II adsorption upon the addition of 1000 μM Fe II . Fe II interferes with the ability of picolinic acid to cause divalent metal ion release.

Effects of composition and structure of alginates on adsorption of divalent metals

Results of a series of experiments (on the adsorption of divalent metal ions by dried alginic acid, Na and Ca alginates of different composition and block structure) conducted in this systematic study of the effects of the composition and structure of alginates on the static adsorption equilibrium of divalent metal ions indicate that the properties of alginate adsorption to divalent metal ions are highly different, depending not only on the cations used, but also on the form and structure of the alginates. There is close correlation between the adsorption properties and the structure of the alginates. The selectivity coefficient of Na alginate for Cd-Sr ion exchange tends to increase with the increase of theM/G ratio in alginate, whereas the adsorption capacity of Ca alginate for Cu2+ ion decrease with the increase of the G-block or the average length of the G-block $$(\bar N_G )$$ and the total adsorption capacity of alginic acid is found to vary in the same order as theF MM(diad frequency) in alginate in the mixed solution of Sr2+, Ba2+ and Cd2+.

An equilibrium study of adsorption of divalent metal ions onto a metal oxide adsorbent.

Equilibrium adsorption behavior of divalent metal ions onto hydrous titanium (IV) oxide (HTO) was studied. A general equilibrium adsorption equation was derived from three simultaneous equilibrium reactions: (1) hydrolysis of metal ions to the hydroxides, (2) deprotonation of hydroxyl groups (adsorption sites) on HTO’s surface and (3) complexation, of the hydroxides with the deprotonated sites. The theoretical equilibrium adsorption equation was confirmed by several experimental results under acidic or basic conditions using uranium, lead, cadmium and zinc ions as the adsorbates. It is demonstrated that two parameters within the equation provide information about the adsorption capacity and the selectivity of adsorbent for target metal ions. The HTO employed here had available sites of 7.15 × 10–4 mol·g–1 for all experiments. Metal ions were adsorbed preferentially on the HTO in the following sequence: Zn2+ 2+ 2+ 22+.

The Rates of Adsorption of Divalent Metal Ions on Polyacryloylacetone.

The Rates of Adsorption of Divalent Metal Ions on Polyacryloylacetone.

Properties of polyacryloylacetone for adsorption of divalent metal ions

Polyacryloylacetone (PAA) was prepared by polymerizing acryloylacetone in a sealed tube, and examined as an adsorbent of divalent metal ions. The dissociation constant of PAA and overall binding constants of PAA-metal complexes were determined from experimental data on pH titration. The adsorptions of metal ions on PAA were in the order Hg( ii) ⪢ Cu( ii) > Ni( ii) > Co( ii) > Cd( ii) , showing high selectivity for Hg( ii). The adsorption depended significantly on the pH of the solution. The uses of a PAA column for separation and concentration of metal ions were also examined.

Interaction of nickel ions with a γ-Al 2O 3 support during deposition from aqueous solution

The interaction of nickel ions with a γ-Al 2O 3 support was studied using potentiometric titration during deposition from aqueous solution and temperature-programmed reduction of calcined samples. It was found that in calcined samples of low nickel content, nickel is present exclusively as a “surface aluminate.” With higher metal loadings a separate NiO phase was detected. From potentiometric titration experiments it was concluded that a precursor of the surface spinel, viz., a mixed hydroxide surface compound, is already formed in aqueous solution. The initial interaction of nickel ions with the alumina support is discussed in terms of specific adsorption of divalent metal ions.