Chelation ion‐exchange properties of copolymer resin derived from 4‐hydroxyacetophenone,oxamide, and formaldehyde

A copolymer (4‐HAOF) prepared by condensation of 4‐hydroxyacetophenone and oxamide with formaldehyde in the presence of an acid catalyst proved to be a selective chelating ion‐exchange copolymer for certain metals. Chelating ion‐exchange properties of this copolymer were studied for Fe³⁺, Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺, Cd²⁺, Pb²⁺, and Hg²⁺ ions. A batch equilibrium method was employed in the study of the selectivity of metal‐ion uptake involving the measurements of the distribution of a given metal ion between the copolymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The copolymer showed a higher selectivity for Fe³⁺ ions than for Co²⁺, Zn²⁺, Cd²⁺, Pb²⁺, Cu²⁺, Ni²⁺, and Hg²⁺ ions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 787–790, 2003     

Synthesis of resin IV: Salicylic acid,diaminonaphthalein, and formaldehyde terpolymer and its ion exchange

This article reports the synthesis, characterization, and ion exchange properties of a terpolymer. The terpolymer resin salicylic acid‐diaminonaphthalein‐formaldehyde (SDNF) was synthesized by the condensation of salicylic acid and diaminonaphthalein with formaldehyde in the presence of a hydrochloric acid catalyst. Terpolymer resin was characterized by elemental analysis, infrared (IR) spectroscopy, nuclear magnetic resonance spectroscopy, and UV–Visible spectral studies. The number average molecular weight of the resin was determined by nonaqueous conductometric titration. Chelation ion exchange properties have also been studied for Fe³⁺, Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺, Cd²⁺, Pb²⁺ ions employing a batch equilibrium method. It was employed to study the selectivity of metal ion uptake involving the measurements of distribution of a given metal ion between the polymer sample and a solution containing the metal ion. The study was carried out over wide pH range and in a media of various ionic strengths. The terpolymer showed higher selectivity for Fe³⁺, Cu²⁺, and Ni²⁺ions than for Co²⁺, Zn²⁺, Cd²⁺, and Pb²⁺ ions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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.     

Facilitated Transport of Cadmium Ions from Hydrochloric Acid Solutions through a Liquid Membrane Containing Dicyclohexyl‐18‐Crown‐6 as Extractant‐Carrier

Abstract

The transport of cadmium ions from hydrochloric acid solutions across a bulk liquid membrane by using dicyclohexyl‐18‐crown‐6 (DC18C6) dissolved in dichloromethane has been studied at 25°C. The effect of the fundamental parameters influencing the transport, e.g., hydrochloric acid concentration in the feed phase, DC18C6 concentration and the type of diluent used in the membrane and time of transport have been investigated. The transported amount of the cadmium ions (initial concentration 0.001 M) from a 6 M hydrochloric acid solution across a dichloromethane solution of DC18C6 (0.05 M) into distilled water (receiving phase) was found to be 98.3 (±1.8) percent after 6 h. The selectivity and efficiency of the method toward cadmium ions were tested by performing the competitive transport experiments on the mixtures containing Cd²⁺, Ni²⁺, Mn²⁺, Co²⁺, Zn²⁺, Pb²⁺, and Fe²⁺ ions. The best selectivity was found for the recovery of the cadmium ions from its mixture with Ni²⁺, Mn²⁺, Co²⁺, and Pb²⁺ ions. Thus, the method can be proposed for the application in cadmium recovery from the sources containing these ions such as spent rechargeable nickel‐cadmium batteries.     

Binding of heavy metal ions by formaldehyde-polymerized peanut skins

Peanut skin, when treated with formaldehyde to polymerize tannins, is a highly efficient substrate for removal of many heavy metal ions from aqueous waste solutions. The ions Ag¹⁺, Cd²⁺, Cr⁶⁺, Cu²⁺, Hg²⁺, Ni²⁺, Pb²⁺, Zn²⁺, as well as Ca²⁺ and Mg²⁺, were contacted with formaldehyde-treated peanut skin. Quantitative removal could be achieved with Ag¹⁺, Cd²⁺, Cu²⁺, Hg²⁺, Pb²⁺, and Zn²⁺. Capacity of the substrate for ions was promising for Pb²⁺ (2.1 meq/g substrate), Cu²⁺ (3.0 meq/g), and Cd²⁺ (1.3 meq/g). Sorption from a solution containing Cd²⁺, Cu²⁺, Hg²⁺, Ni²⁺, Pb²⁺, Zn²⁺, on a packed column of formaldehyde-treated peanut skin indicated that Hg²⁺, Pb²⁺, and Cu²⁺ were rapidly and completely bound to the packing, while Cd²⁺, Ni²⁺, and Zn²⁺ were poorly bound until the preferred ions had been removed from solution.     

Equilibrium,kinetic and isotherm of some metal ion biosorption

Trichoderma reesei was used as a biosorbent for the removal of Co²⁺, Cu²⁺, Ni²⁺, Pb²⁺ and Zn²⁺ ions. The influence of factors such as pH, mass of biomass, contact time and temperature on biosorption efficiency was optimized. To calculate the isotherm parameters for the biosorption of Co²⁺, Cu²⁺, Ni²⁺, Pb²⁺ and Zn²⁺ ions at optimized conditions, the experimental equilibrium data were fitted to Langmuir and Freundlich models. The calculated thermodynamic parameters, ΔG°, ΔH° and ΔS° showed that the biosorption of Co²⁺, Cu²⁺, Ni²⁺, Pb²⁺ and Zn²⁺ ions onto T. reesei biomass was feasible, spontaneous and endothermic at the optimized conditions. The results of kinetic analysis showed that the biosorption of the selected metal ions onto T. reesei biomass obeys pseudo second order kinetics.     

Chelation ion‐exchange study of copolymer resin derived from 8‐hydroxyquinoline 5‐sulphonic acid,oxamide, and formaldehyde

Copolymers (8‐HQ5‐SAOF) were synthesized by the condensation of 8‐hydroxyquinoline 5‐sulphonic acid (8‐HQ5‐SA) and oxamide (O) with formaldehyde (F) in the presence of acid catalyst. Four different copolymers were synthesized by using varied molar proportion of the reacting monomers. Copolymer resin composition has been determined on the basis of their elemental analysis and average molecular weights of these resins were determined by conductometric titration in nonaqueous medium. Viscometric measurement in dimethyl sulphoxide (DMSO) has been carried out with a view to ascertain the characteristic functions and constants. Electronic spectra, FTIR, and proton nuclear magnetic resonance spectra were studied to elucidate the structures. The newly synthesized copolymer proved to be a selective chelating ion‐exchange copolymer for certain metals. The chelating ion‐exchange properties of this synthesized copolymer was studied for different metal ions such as Fe³⁺, Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺, Cd²⁺, and Pb²⁺. A batch equilibrium method was used in the study of the selectivity of metal ion uptake involving the measurements of the distribution of a given metal ion between the copolymer sample and a solution containing the metal ion only for representative copolymer 8‐HQ5‐SAOF‐I due to economy of space. The study was carried out over a wide pH range, shaking time, and in media of various ionic strengths. The copolymer showed a higher selectivity for Fe³⁺, Cu²⁺, and Ni²⁺ ions than for Co²⁺, Zn²⁺, Cd²⁺, and Pb²⁺ ions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Selective and Efficient Liquid Membrane Transport of Thallium (III) Ion by Potassium‐dicyclohexyl‐18‐crown‐6 as Specific Carrier

Abstract

Potassium‐dicyclohexyl‐18‐crown‐6 was used as a selective and efficient carrier for the uphill transport of thallium (III) ion as [TlCl₄]^? complex ion through a chloroform bulk liquid membrane. By using oxalate anion as a metal ion acceptor in the receiving phase, the amount of thallium (III) transported across the liquid membrane after 120 min was 96±2%. The selectivity and efficiencies of thallium transport from aqueous solutions containing Cu²⁺, Zn²⁺, Ni²⁺, Cd²⁺, Pb²⁺, Co³⁺, Mn²⁺ _, Cr³⁺, Mg²⁺, Ca²⁺, K⁺, Na⁺, and Fe³⁺ ions were investigated. In the presence of Na₃PO₄ (0.01 M) at pH=3 as a suitable precipitation agent in the source phase, the interfering effect of Pb²⁺ ion were diminished drastically.     

Liquid-liquid extraction of metal ions,DFT and TD-DFT analysis for some pyrane derivatives with high selectivity for Fe(II) and Pb(II)

Liquid-liquid extraction of metal ions using pyrane derivatives was studied. Fe²⁺, Zn²⁺, Cu²⁺, Co²⁺, Cd²⁺, Ni²⁺, and Pb²⁺ were extracted from the aqueous phase into the organic phase and the extractability for each metal was determined by atomic absorption. Interestingly, a competitive extraction was also investigated and then examined at different pH in order to explore the effect of the different substituent groups on metal extraction. We found high selectivity towards Fe²⁺ (91.8%) and Pb²⁺ (90.7%). In addition, geometry optimizations of the ground and excited-states of the selective ligands in order to get better insight into the geometry and the electronic structure were carried out by DFT and TD-DFT calculations.     

Sorption Studies of Terpolymers Based on p-Nitrophenol,Triethylenetetramine, and Formaldehyde

Terpolymer resins have been synthesized by condensation of p-nitrophenol, triethylenetetramine, and formaldehyde in the presence of 2 M NaOH as a catalyst with different molar proportions of monomers. Newly synthesized terpolymers were proved to be selective chelation ion exchangers for metal ions like Fe³⁺, Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺, Cd²⁺, Hg²⁺, and Pb²⁺. A batch equilibrium study was carried out over a wide pH range, shaking time, and in media of various ionic strengths of different electrolytes and shows higher selectivity for Hg²⁺, Cd²⁺, and Pb²⁺. Distribution ratios of metal ions were found to be increased by increasing pH of solutions; hence the resins can be used to recover certain metals from waste solutions and removal of iron from boiler water.     

Synthesis of a highly selective bis-rhodamine chemosensor for naked-eye detection of Cu ions and its application in bio-imaging

A bis-rhodamine based fluorescent chemosensor for naked-eye detection of Cu²⁺ with enhanced sensitivity as compared to mono-rhodamine derivative has been synthesized, and its selectivity for Cu²⁺ in the presence of other competitive metal ions (Li⁺, Na⁺, K⁺, Cs⁺, Mg²⁺, Ca²⁺, Sr²⁺, Cr³⁺, Mn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Zn²⁺, Cd²⁺, Hg²⁺, and Pb²⁺), and application in bio-imaging are demonstrated.     

Synthesis of a highly selective bis-rhodamine chemosensor for naked-eye detection of Cu2+ ions and its application in bio-imaging

A bis-rhodamine based fluorescent chemosensor for naked-eye detection of Cu²⁺ with enhanced sensitivity as compared to mono-rhodamine derivative has been synthesized, and its selectivity for Cu²⁺ in the presence of other competitive metal ions (Li⁺, Na⁺, K⁺, Cs⁺, Mg²⁺, Ca²⁺, Sr²⁺, Cr³⁺, Mn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Zn²⁺, Cd²⁺, Hg²⁺, and Pb²⁺), and application in bio-imaging are demonstrated.     

Sorption behavior of ion-exchange terpolymer resin with environmental impact: synthesis,characterization and isotherm models

A novel terpolymer acts as an effective chelating ion exchanger which was synthesized using 2-amino-6-nitro-benzothiazole and semicarbazide with formaldehyde (BSF) by solution condensation technique. Its ion exchange properties was determined against certain metal ions viz. Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺ and Pb²⁺ using batch equilibrium technique with different electrolyte concentrations, pH ranges and time intervals. The results of batch studies revealed that the separation of the selected metal ions from the aqueous solution by the terpolymer is found to be excellent compared to the available commercial resins and earlier reported resins. The order of metal ion uptake at higher concentrations by the BSF terpolymer at lower pH is Cu²⁺ > Ni²⁺ > Fe³⁺ and at lower concentration at higher pH is Zn²⁺ > Co²⁺ > Pb²⁺. The reusability of the resin was also reported for its effective ion-exchange behaviour for several cycles. The adsorption isotherm model was evaluated and the results are in good agreement with each other. The order of kinetics was also determined and the resin follows pseudo-second-order kinetics. Moreover, the physico-chemical analysis gives strong evidence for the effective metal ion removal compared with the earlier reported and commercial resins. Earlier, the structure and the properties of the synthesized novel chelating resin were clearly elucidated by elemental, FTIR, UV–Vis, ¹H & ¹³C NMR spectra, GPC, SEM and XRD.     

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.     

SORPTION PROCESSES OF NATURAL IRANIAN BENTONITE EXCHANGED WITH CD2+, CU2+, NI2+, AND PB2+ CATIONS

Experimental studies on the retention of cadmium (Cd²⁺), copper (Cu²⁺), nickel (Ni²⁺), and lead (Pb²⁺) by bentonite samples from Iran were conducted using single- and multiple-component solutions. Based on the sorption capacity of bentonite the following order was obtained for single- and multiple-component solutions: Pb²⁺ > Cd²⁺ > Ni²⁺ > Cu²⁺. The maximum adsorption capacities of bentonite with metals in single- and multiple-component solutions were 29.5%, 22.5%, 19.2%, and 17.1% and 13.5%, 13.4%, 12.1%, and 9.1% for Pb²⁺, Cd²⁺, Ni²⁺, and Cu²⁺, respectively. Desorption isotherms of Cd²⁺, Cu²⁺, Ni²⁺, and Pb²⁺ deviated significantly from the sorption isotherms, thereby indicating irreversible or very slowly reversible sorption. Finally, soil solution saturation indices and metal speciation were assessed using the Visual MINTEQ 2.6 program and the probability of mineral precipitation was supported by scanning electron microscopy.     

Highly Selective and Efficient Membrane Transport of Copper as Cu(SCN)2− 4 Ion Using K+-Dicyclohexyl-18-crown-6 as Carrier

Abstract

Potassium-Dicyclohexyl-18-Crown-6 Complex Was Used As A Highly Efficient Carrier For The Uphill Transport Of Copper As Cu(SCN)^2? ₄ Complex Ion Through A Chloroform Bulk Liquid Membrane. By Using Histidine As A Metal Ion Acceptor In The Receiving Phase At The Optimum Ph Of 7.4, The Amount Of Copper Transported Across The Liquid Membrane After 2 Hours Was 90.2 ± 1.0%. The Selectivity And Efficiency Of Copper Transport From Aqueous Solutions Containing Equimolar Mixtures Of Ag⁺, Cd²⁺, Zn²⁺, Ni²⁺, Fe²⁺, Co²⁺, Pb²⁺, Mn²⁺, Fe³⁺, Bi³⁺, And Cr³⁺ Ions Were Investigated. In The Presence Of Pyrophosphate As A Suitable Masking Agent In The Source Phase, The Interfering Effects Of Co²⁺, Zn²⁺, Pb²⁺, And Cd²⁺ Ions Were Completely Eliminated.     

Treatment of industrial wastewater using zeolitite and sepiolite,natural microporous materials

This work investigates the ability of natural microporous materials, such as a zeolite-rich tuff (zeolitite) and a modulated phyllosilicate (sepiolite), to remove heavy-metal ions from simulated inorganic polluted industrial wastewater. Fixed beds of sepiolite and zeolitite were percolated by a solution of Co²⁺, Cu²⁺, Zn²⁺, Cd²⁺, and Pb²⁺ (concentration of each cation, 2 ? 10^?3 N; total concentration, 10^?2 N) and were regenerated with a 2 ? 10^?3 N Na⁺ solution. The order of decreasing affinity was, for sepiolite: Cu²⁺ > Zn²⁺ > Cd²⁺ > Pb²⁺ ? Co²⁺, and, for zeolitite: Pb²⁺ “Cd²⁺ > Cu²⁺ > Zn²⁺ > Co²⁺. After regeneration with Na⁺ solution, a fraction of the retained heavy metals was quickly released by the beds as follows: sepiolite, Co²⁺ ? Pb²⁺ > Cd²⁺ > Zn²⁺ > Cu²⁺; zeolitite, Cd²⁺ > Cu²⁺ ? Zn²⁺ > Co²⁺ > Pb²⁺. XRD and DTA-TGA analyses examined structural changes in the natural and final materials.     

Competitive Adsorption of Ag+, Pb2+, Ni2+, and Cd2+ Ions on Vermiculite

Competitive adsorption of Ag⁺, Pb²⁺, Ni²⁺, and Cd² ions on vermiuculite in a binary, ternary, and quaternary mixture was investigated in batch experiments. The effects of the presence of Ag⁺, Ni²⁺, and Cd²⁺ ions on the adsorption of Pb²⁺ ions were investigated in terms of the equilibrium isotherm. Experimental results indicated that Pb²⁺ ions always favorably adsorbed on vermiculite over Ag⁺, Ni²⁺, and Cd²⁺ ions. The adsorption equilibrium data of Pb²⁺ ions better fitted the Langmuir model than the Freundlich model. The results showed that the pseudo-second-order kinetics model was in good agreement with the experimental results for all metal ions, and the adsorption rate among the metal ions followed Ag⁺ > Pb²⁺ > Ni²⁺ > Cd²⁺. The desorption and regenration study indicated that vermiculite can be used repeatedly and be suitable for the design of a continuous process.     

Toxic metal ion removal by terpolymer ion-exchanger from aqueous environments: synthesis,thermal degradation,batch separation,kinetic and isotherm studies

A novel chelating resin was synthesized and characterized by elemental, physico-chemical, GPC, NMR, and SEM analyses. Batch separation was adopted to study the recovery of selected metal ions with respect to the pH, time, concentrations, and electrolytes. From the results, it was observed that the order of the rate of metal ion uptake by the resin was Fe³⁺ > Cu²⁺ > Zn²⁺ > Ni²⁺ > Co²⁺ > Pb²⁺ ions. The adsorption kinetics follows first order, and isotherm models were also found to fit each other. The resin showed three-step thermal degradation, and its kinetic and thermodynamic parameters were also evaluated.     

Adsorption characteristics of metal ions by CO2-fixing Chlorella sp. HA-1

Single and binary metal systems were employed to investigate the removal characteristics of Pb²⁺, Cu²⁺, Cd²⁺, and Zn²⁺ by Chlorella sp. HA-1 that were isolated from a CO₂ fixation process. Adsorption test of single metal systems showed that the maximum metal uptakes were 0.767 mmol Pb²⁺, 0.450 mmol Cd²⁺, 0.334 mmol Cu²⁺ and 0.389 mmol Zn²⁺ per gram of dry cell. In the binary metal systems, the metal ions on Chlorella sp. HA-1 were adsorbed selectively according to their adsorption characteristics. Pb²⁺ ions significantly inhibited the adsorption of Cu²⁺, Zn²⁺, and Cd²⁺ ions, while Cu²⁺ ions decreased remarkably the metal uptake of Cd²⁺ and Zn²⁺ ions. The relative adsorption between Cd²⁺ and Zn²⁺ ions was reduced similarly by the presence of the other metal ions.