Removal of Heavy Metal Ions from Water by Cross-Linked Potato Di-Starch Phosphate Polymer

Potato di-starch phosphate polymer was synthesized by cross-linking potato starch with phosphorus oxy-chloride in basic medium and was then dispersed (0.2-1%) in aqueous solutions of divalent heavy metal ions (Cu²⁺, Ni²⁺, Zn²⁺, and Pb²⁺), to investigate their removal efficiency by the starch and was found to increase with increase in the polymeric starch content and increase in the heavy metal ion concentration. The removal order was found to be Pb²⁺ (78.1%) > Cu²⁺ (58.5%) > Zn²⁺ (20.5%) > Ni²⁺ (17.3%) against the constant polymeric starch content. UV-Visible, Fluorescence, FT-IR, SEM, and CHN techniques were used for characterization of different complexes formed.     

Appraisal of microwave-assisted ion-exchange in mordenite by crystal structure analysis

Transition metal-containing mordenite have been prepared by solid state ion exchange with microwave irradiation of mechanical mixtures of CoCl₂·6H₂O, NiCl₂·6H₂O and CuCl₂·2H₂O with mordenite at 750?W microwave power and for 10?C20?min treatment time. The prepared transition metal-mordenite were characterized by X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FT-IR), simultaneous TG and DTA thermal analyses (TG/DTA), surface area measurement (BET), and diffuse reflectance spectroscopy (DRS). The results show that Co²⁺, Ni²⁺, and Cu²⁺ metal ions are actually incorporated into mordenite pores. The extra-framework locations of metal cations were determined Rietveld refinement of XRD data, performed in the Cmcm space group for all three samples. Three metal sites were located: the first site is in an almost perfect boat-shaped coordination with framework oxygen??s, the second site is poorly coordinated while the third metal cation site was found at the center of mordenite cage in six-fold coordination to water molecules.     

Chelating polymer bearing triazolylazophenol moiety as the functional group

The chelating polymer-bearing triazolylazophenol moiety as the functional group was synthesized, its metal adsorption properties for 6 divalent heavy metal ions; Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, and Pb²⁺ were investigated. The capacity of the polymer for Cu²⁺ achieved 8.7 mEq/g in pH 5.3 solution. The polymer showed remarkable color changes from orange to red violet or blue violet with its chelations to the heavy metal ions. The metal adsorption rates of the polymer were rapid in performing complete capacity saturation of heavy metal ions in about 30 min. The capacities varied little the presence of alkali or alkaline earth metal ions in solutions. The perfect elimination of metals from the polymer–M²⁺ chelates were performed with mineral acid solutions. The metal ions; Cu²⁺ and Ni²⁺ in plating-process solutions were effectively removed by the chelating polymer, and the polymer can be practically used for the removal of these ions from waste water.     

The preparation and properties of chelates of transition metal ions with the homopolymer and copolymers of p-vinylbenzoylacetone

p-Vinylbenzoylacetone (VBA) was prepared by the condensation of p-vinylacetophenone and ethyl acetate. This monomer was homopolymerized and copolymerized with acrylamide or maleic anhydride to produce polymers which would chelate substantial amounts of transition metal ions such as Cu²⁺, Ni²⁺, Co²⁺, Eu³⁺, and VO²⁺. In the case of the Cu²⁺ and Ni²⁺ chelates, about 80–90% of the metal ion could be eluted by dilute mineral acids. The resulting eluted products apparently have a somewhat porous structure because they are capable of rechelating these ions from water solution, even though the solid homopolymer which had not been chelated and eluted is too hydrophobic to chelate very much metal ion from water solution. The eluted Cu²⁺ chelate readily reaccepted Cu²⁺ ions from water solution and discriminated against Ni²⁺ almost completely. However, the eluted Ni²⁺ chelate would reaccept both Cu²⁺ and Ni²⁺ ions, but exhibited a strong preference for Cu²⁺ ions in competitive batch experiments. The VO²⁺ chelate was an effective heterogeneous phase catalyst for the epoxidation of allyl alcohols such as geraniol with tert-butylhyroperoxide. The chelate was stable under these oxidative conditions and could be recovered unchanged and reused.     

Selectivity of heavy metal ions at acidic supramolecular surfaces

Langmuir monolayers containing surface carboxylic acid head groups were examined in order to characterize their selectivity to metal ion adsorption. Experimental data of ion adsorption obtained by surface isotherms and FTIR spectroscopy were analyzed using a thermodynamic-and-electrochemical model. Among bivalent ions examined (Cr²⁺, Pb²⁺, Cu²⁺, Cd²⁺, Zn²⁺, Ca²⁺, Ni²⁺, and Ba²⁺), Langmuir monolayers showed the highest selectivity to chromium ions. In addition, it was found that adsorption constants of the surface ions are quite different from binding constants of the bulk ions. The results show important implications to sensing and separating metal ions by the use of acidic supramolecular materials.     

Formation of thermosensitive water‐soluble copolymers with phosphinic acid groups and the thermosensitivity of the copolymers and copolymer/metal complexes

Thermosensitive and water‐soluble copolymers were prepared through the copolymerization of acryloyloxypropyl phosphinic acid (APPA) and N‐isopropyl acrylamide (NIPAAm). The thermosensitivity of the copolymers and copolymer/metal complexes was studied. The APPA–NIPAAm copolymers with less than 11 mol % APPA moiety had a lower critical solution temperature (LCST) of approximately 45°C, but the APPA–NIPAAm copolymers with greater than 21 mol % APPA moiety had no LCST from 25 to 55°C. The APPA–NIPAAm copolymers had a higher adsorption capacity for Sm³⁺, Nd³⁺, and La³⁺ than for Cu²⁺, Ni²⁺ and Co²⁺. The APPA–NIPAAm (10:90) copolymer/metal (Sm³⁺, Nd³⁺, or La³⁺) complexes became water‐insoluble above 45°C at pH 6–7, but the APPA–NIPAAm (10:90) copolymer/metal (Cu²⁺,Ni²⁺, or Co²⁺) complexes were water‐soluble from 25 to 55°C at pH 6–7. The temperature at which both the APPA–NIPAAm copolymers and the copolymer/metal complexes became water‐insoluble increased as the pH values of the solutions increased. The APPA–NIPAAm copolymers were able to separate metal ions from their mixed solutions when the temperature of the solutions was changed; this was followed by centrifugation of the copolymer/metal complexes after the copolymers were added to the metal solutions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 116–125, 2004     

REMOVAL OF Cd2+, Cu2+, AND Ni2+ METALS FROM SIMULATED WASTEWATER IN SINGLE AND COMPETITIVE SYSTEMS USING LOCAL IRAQI PHOSPHATE ROCKS

The equilibrium uptake of cadmium (Cd²⁺), copper (Cu²⁺), and nickel (Ni²⁺) ions, both singly and in combination, by local Iraqi phosphate rocks (PR) was studied in a batch system. The phosphate rock was characterized using BET, FT-IR, XRD, and SEM techniques. Adsorption isotherms were developed for both the single and ternary-component systems and expressed by the mono- and multicomponent Langmuir, Freundlich, Redlich-Peterson, and Dubinin-Radushkevich adsorption models; model parameters were estimated by the nonlinear regression method using STATISTICA version 6 software. To understand the action of metals uptake, factors influencing the adsorption of the heavy metals including pH, initial metal ion concentration, weight of the adsorbent, mixing speed, contact time, and temperature were investigated. It was found that the mono- and multicomponent adsorption equilibrium data fitted very well to the Langmuir model with high determination coefficient (R ²). The maximum loading capacities (q _max) were 70.852, 53.372, and 48.045 mg/g for Cd²⁺, Cu²⁺, and Ni²⁺ respectively. However, in the ternary system the loading capacity decreased because of competition between ions to binding sites of the adsorbent. Adsorption data were modeled using the pseudo-first- and pseudo-second-order kinetic and intraparticle diffusion models. It was seen that the pseudo- first-order kinetic equation could best describe the adsorption kinetics. Thermodynamic parameters showed that the adsorption of investigated heavy metals onto PR was endothermic and spontaneous in nature and the process is physiosorption. Fourier transform-infrared spectroscopy (FT-IR) analysis indicated that carboxylic (C?O), phosphine (p-H), and hydroxyl (–OH) groups in PR played an important role in the adsorption process. In conclusion, PR was found suitable as an abundant adsorbent for removal of the selected metal ions from aqueous solutions.     

Synthesis,characterization, metal sorption,and biological activity of poly(N‐heterocylic acrylamide)

N‐heterocyclic acrylamide monomers were prepared and then transferred to the corresponding polymers to be used as an efficient chelating agent. Polymers reacted with metal nitrate salts (Cu²⁺, Pb²⁺_, Mg²⁺, Cd²⁺, Ni²⁺, Co²⁺_, Fe²⁺) at 150°C to give metal‐polymer complexes. The selectivity of the metal ions using prepared polymers from an aqueous mixture containing different metal ion sreflected that the polymer having thiazolyl moiety more selective than that containing imidazolyl or pyridinyl moieties. Ion selectivity of poly[N‐(benzo[d]thiazol‐2‐yl)acrylamide] showed higher selectivity to many ions e.g. Fe³⁺, Pb²⁺, Cd²⁺, Ni²⁺, and Cu²⁺. While, that of poly[N‐(pyridin‐4‐yl)acrylamide] is found to be high selective to Fe³⁺ and Cu²⁺ only. Energy dispersive spectroscopy measurements, morphology of the polymers and their metallopolymer complexes, thermal analysis and antimicrobial activity were studied. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42712.     

Characterization of Adsorptive Capacity and Investigation of Mechanism of Cu2+, Ni2+ and Zn2+ Adsorption on Mango Peel Waste from Constituted Metal Solution and Genuine Electroplating Effluent

Abstract

The present study reports the potential of mango peel waste (MPW) as an adsorbent material to remove Cu²⁺, Ni²⁺, and Zn²⁺ from constituted metal solutions and genuine electroplating industry wastewater. Heavy metal ions were noted to be efficiently removed from the constituted solution with the selectivity order of Cu²⁺ > Ni²⁺ > Zn²⁺. The adsorption process was pH-dependent, while the maximum adsorption was observed to occur at pH 5 to 6. Adsorption was fast as the equilibrium was established within 60 min. Maximum adsorption of the heavy metal ions at equilibrium was 46.09, 39.75, and 28.21 mg g for Cu²⁺, Ni²⁺, and Zn²⁺, respectively. Adsorption data of all the three metals fit well the Langmuir adsorption isotherm model with 0.99 regression coefficient. Release of alkali and alkaline earth metal cations (Na⁺, K⁺, Ca²⁺, Mg²⁺) and protons H⁺ from MPW, during the uptake of Cu²⁺, Ni²⁺, and Zn²⁺, and EDX analysis of MPW, before and after the metal sorption process, revealed that ion exchange was the main mechanism of sorption. FTIR analysis showed that carboxyl and hydroxyl functional groups were involved in the sorption of Cu²⁺, Ni²⁺, and Zn²⁺. MPW was also shown to be highly effective in removing metal ions from the genuine electroplating industry effluent samples as it removed all the three metal ions to the permissible levels of discharge legislated by environment protection agencies. This study indicates that MPW has the potential to effectively remove metal ions from industrial effluents.     

Adsorption and equilibrium adsorption modeling of bivalent metal cations on viscose rayon succinate at different pHs

A viscose rayon succinate (VRS) was studied as a chelating fiber for the removal of metal ions from an aqueous solution. VRS was synthesized successfully from viscose rayon (VR) and succinic anhydride in the presence of dimethylsulfoxide (DMSO), and was characterized by C¹³ nuclear magnetic resonance ¹³C NMR, scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) analysis. The maximum bivalent metal ion adsorption capacity of the VRS was 6.2 meq/g. Studies on the adsorption behaviour of VRS and its ability to remove bivalent trace metals such as Cu²⁺, Zn²⁺, Pb²⁺, and Ni²⁺ from an aqueous solution were performed both by FT-IR and quantitative analyses at different pHs. The results showed that the adsorption of metals on VRS increased as pH increased, and furthermore, that the adsorption capacity of metal ions could be classified as Cu²⁺ > Zn²⁺ > Ni²⁺ > Pb²⁺. The adsorption modeling for the interpretation of empirical data was carried out by assuming a probability factor, P(A), and a degree of protonation, χ. Surface potential, Ψ₀, and an effective ratio of surface equilibrium constants, K_effect, were obtained using the model.     

Metal ion permeation properties of silk fibroin/chitosan blend membranes

Silk fibroin/chitosan (SF/CS) blend membranes were prepared and characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy. It was found that SF and CS were compatible in the blend membranes and that the membranes were dense without microscopic phase separation. Swelling experiments showed that the swelling ratio of the blend membranes increased with CS content and reached the highest value when CS content was 70 wt%. Experiments indicated that the permeability coefficient of K⁺ through the blend membrane was 2–4 times higher than that of pure CS membrane, and 10 times higher than that of pure SF membrane. The permeation rate of K⁺ increased linearly with CS content in the blend membrane for the lower concentration feeding solution. For different metal ions, the permeability through SF/CS blend membranes was in the sequence K⁺ > Ca²⁺ > Cd²⁺ > Pb²⁺ > Cu²⁺ > Ni²⁺. Copyright © 2006 Society of Chemical Industry     

Concentration and separation of aqueous solutions of Cu2+, Ni2+, Fe3+ by dextran

The effects of water-soluble polymers on the concentration and separation of the aqueous solutions of the metal ions have been studied. The separation of metal ions can be possible by ultrafiltration-complexation process. The effect of Dextran, which is a water-soluble polymer, on the concentration and separation of metal ions (Cu²⁺, Ni²⁺, Fe³⁺) have been investigated by using EC-PEG 4000 alloy membranes. The permeability of these membranes for metal ions has been rrecorded at constant pressure but different pH values. It has been notices that the highest water-permeable membrane is also permeable towards Cu²⁺ and Ni²⁺, but has shown a considerable retention for Fe³⁺ as a result of the hydrolysis of Fe³⁺. The retentions of metallic ions and metallic-ion-Dextran couples have been determined at constant pressure but different pH and polymer concentration values. It has been shown that Fe³⁺/Ni²⁺ and Fe³⁺/Cu²⁺ couples can be separated by using Dextran. © 1995 John Wiley & Sons, Inc.     

Overcoming the inhibition effects of metal ions in the degradation of benzene and toluene byalcaligenes xylosoxidans y234

The effects of metal ions on the biodegradation of benzene and toluene were investigated. Among 12 tested metal ions, Cu²⁺, Ni²⁺, Co²⁺ and A⁺ _g inhibited the degradation of benzene and toluene severely byAlcaligenes xylosaxidans Y234. Cu²⁺ was found to inhibit catechol 1,2-dioxygenase in the degradation of benzene and toluene. Co²⁺ and Ni²⁺ were supposed to inhibit benzoate 1,2-dioxygenase, while Ag⁺ was supposed to inhibit benzaldehyde dehydrogenase in the degradation of toluene. The inhibition effect caused by these metal ions could be overcome both by microbial adaptation and by adding specific aromatic compounds to the broth.     

Studies of Retention and Reusable Capacities of Melamine Formaldehyde Based Terpolymer Against Some Toxic Metal Ions by Batch Equilibrium Method

Chelating terpolymer resin was synthesized and characterized by elemental, physico-chemical, spectral, SEM, XRD, and GPC to elucidate the structure and properties of the terpolymer. Ion-exchange analysis involving evaluation of metal ion uptake in different electrolyte concentrations, pH, and time have been studied to assess the retention capacities of the terpolymer for the metal ions viz. Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, and Pb²⁺. The adsorption isotherm was evaluated using the Langmuir and Freundlich isotherms models and the results were found best fitting with each other. The resin can be successfully used in the field of recovery of metal ions from effluents and contaminated water.     

Nickel(III) and Copper(III) Complexes with 13- and 14-membered Tetra-aza Macrocycles. Ring-size and Medium Effects on the MIII/MII Redox Couple Potentials

The one-electron oxidation of the Ni^II and Cu^II complexes with 13- and 14-membered macrocycles 1 and 2 to produce authentic Ni^III and Cu^III species has been electrochemically investigated and the E_1/2 values associated to the reversible M^III/M^II redox couple have been determined by means of the Differential Pulse Voltammetry technique. The 13-membered ring favours the attainment of the Cu^III state, whereas the 14-membered ring favours the formation of the Ni^III complex. This opposite behaviour is satisfactorily interpreted in terms of size of the metal ions and aperture of the macrocyclic cave. Moreover the effect of the concentration of the inert electrolyte (NaClO₄, 0.1–7.0 M) on the E_1/2(M^III/M^II) values has been investigated: the increase of the NaClO₄ concentration favours the formation of the Cu^III complexes and disfavours the formation of the Ni^III species. This behaviour is ascribed to the destabilization of Ni^III and Cu^II complexes induced by perchlorate ion through the formation of hydrogen bonds with water molecules axially coordinated to the metal ions.     

Preparation of aminoalkyl celluloses and their adsorption and desorption of heavy metal ions

Aminoalkyl celluloses (AmACs) were prepared from 6-chlorodeoxycellulose and aliphatic diamines H₂N(CH₂)_mNH₂ (m = 2, 4, 6, 8). Their adsorption and desorption of divalent heavy metal ions such as Cu²⁺, Mn²⁺, Co²⁺, Ni²⁺ and their mixtures were also investigated in detail. Adsorption of metal ions on AmACs was remarkably affected by the pH of the solution, the metal ion and its initial concentration, and also the number of methylene units in the diamines. No adsorption of metal ions occurred on AmACs in strongly acidic solutions. However, metal ions were adsorbed rapidly on AmACs from weakly acidic solutions and the amount of adsorption increased with increasing pH. The effectiveness of AmACs as adsorbents decreased with increasing length of the methylene moiety, and AmACs from ethylenediamine (m = 2) was most effective. The adsorption of metal ions on AmACs was in the order Cu²⁺ > Ni²⁺ > Co²⁺ > Mn²⁺. Accordingly, their behavior followed the Irving-Williams series and Cu²⁺ ions were preferentially adsorbed from solutions containing metal ion mixtures. The adsorbed ions were easily desorbed from the AmACs by stirring in 0.1 M HCl.     

Synthesis and properties of hydrophilic polymers, 5. Viscosimetric study on poly(acrylamide-co-4-vinylpyridine) and its interaction with metal ions in aqueous solution

Poly(acrylamide-co-4-vinylpyridine) synthesized by radical bulk polymerization behaves in water as a typical polyelectrolyte. According to the viscosimetric studies, the addition of strong electrolytes, like KNO₃ (0.1 M), completely suppressed the polyelectrolyte effect. The interactions between this copolymer and a number of metal ions were also studied by viscosimetry in aqueous solution. The reduced viscosity decreased with an increase of the copper(II) concentration due to an intrapolymeric complex formation. It was shown that the reduced viscosity of the polymer-metal complexes depends on the pH. It decreased for a constant ratio between the copolymer and the metal ions Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺. Among these cations, Cu²⁺ showed the strongest effect. These results were compared with the corresponding data of both homopolymers.     

Synthesis and study of the chelating properties of 3-carboxy-4-hydroxyacetophenone-formaldehyde resins

3-Carboxy-4-hydroxyacetophenone (CHAP) was polycondensed with various proportions of formaldehyde using alcoholic alkali as catalyst. The resin samples, designated as CHAP-F, have been characterized by elemental analyses and IR spectroscopy, by estimation of their number average molecular weights (M?_n), by measurement of intrinsic viscosity, and by TGA. Polymeric metal chelates of one CHAP-F sample with Cu²⁺, Fe³⁺, Co²⁺, Ni²⁺, and UO₂²⁺ ions have been prepared and characterized. Ion-exchanging properties of one CHAP-F resin sample for Fe³⁺, Cu²⁺, and Ni²⁺ metal ions are studied by the application of the batch-equilibration method.     

Synthesis,characterization, and metal ion uptake studies of chelating resins derived from formaldehyde/furfuraldehyde condensed phenolic schiff base of 4,4′‐diaminodiphenylmethane and o‐hydroxyacetophenone

The synthesis, characterization, and metal ion uptake studies of two chelating resins with multiple functional groups are reported. The chelating resins were synthesized by condensing a phenolic Schiff base derived from 4,4′‐diaminodiphenylmethane and o‐hydroxyacetophenone with formaldehyde or furfuraldehyde. The resins readily absorbed transition metal ions, such as Cu²⁺ and Ni²⁺, from dilute aqueous solutions. The Schiff base, resins, and metal polychelates were characterized by various instrumental techniques, such as elemental‐analysis, ultraviolet–visible spectroscopy proton and carbon‐13 nuclear magnetic resonance spectroscopy (¹H‐NMR and ¹³C‐NMR, respectively), X‐ray diffraction (XRD), and thermogravimetric–differential thermogravimetric analyses (TG–DTG). The ¹H‐NMR and ¹³C‐NMR studies were used to determine the sites for aldehyde condensation with the phenolic moiety. Fourier transform infrared data provided evidence for metal–ligand bonding. Thermogravimetric analysis was employed to compare the relative thermal stabilities of the resins and the polychelates. The TG data were fitted into different models and subjected to computational analysis to calculate the kinetic parameters. The XRD data indicate that the incorporation of metal ion into the resin matrix significantly enhanced the degree of crystallinity of the material. The extent of metal‐ion loading into the resins was studied in competitive and noncompetitive conditions, varying the time of contact, metal ion concentrations, and pH of the reaction medium in a suitable buffer medium. The furfuraldehyde‐condensed resin was more effective in removing metal ions than the formaldehyde‐condensed resins. The resins were selective for Cu²⁺, resulting in separation of Cu²⁺ and Ni²⁺ from the mixture at pH 5.89. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 570–581, 2003     

Competitive Metal Ion Binding to a Silicate-Immobilized Datura innoxia Biomaterial

Abstract

Metal ion binding with a flowing system to a biosorbent comprised of cultured cell-wall fragment within a polysilicate matrix has been investigated. Solutions containing 0.10 mM Pb²⁺, Cu²⁺, Ni²⁺, Cd²⁺, and Zn²⁺ were exposed to the material in combinations of two, three, and five metals while simultaneously monitoring the concentration of all metals in the effluent stream. A relative affinity order of Pb²⁺ > Cu²⁺ >> Zn²⁺ ≈ Cd²⁺ > Ni²⁺ was determined when all five metal ions were exposed to the material. Lower-affinity metal ions were exposed to the material sequentially. Both metal-specific and common binding sites were observed for each metal ion. The presence of both binding sites that are common to all metal ions investigated and sites that appear to be unique for each metal ion could significantly impact the utility of single-metal ion studies on the application of such biosorbents for the selective removal of metal ions from natural water.