Ammonia removal from real wastewater using a LEWATIT S 108 H resin: A batch process and fixed-bed column

ABSTRACT

The ammonia component represents a sizable portion of pollutants in mining wastewater (MW) and because of its high selectivity toward ammonia, a LEWATIT resin was tested in the batch adsorption using different masses with 22.7 mg/L NH₃ ? N and in the continuous adsorption using two fixed-bed columns. Also, resin regeneration was achieved using diluted HCl. The results show the adsorption follows Freundlich isotherm in the batch study and was characterized by both the Bohart–Adams and Thomas models in the fixed-bed column. HCl can be used to regenerate LEWATIT with efficiency 40% and 70% for the small and large column, respectively.     

Hydrometallurgy Wastewater Split-Up by Fluidized-Bed Ion-Exchange Continuous Equipment

ABSTRACT

A proposed operation of a semicontinuous fluidized-bed ion-exchange system was studied. The system splits a liquid current into two currents, one being more concentrated and the other more depleted. This operating technique has been used to split up a mixture of alkaline ions (Na⁺, K⁺) using a strongly acidic resin. The equipment operates simultaneously in two multistage columns, one for loading and the other for elution of the resin. The experimetal testing system employs a hydrometallurgy wastewater containing cobalt and copper as heavy metallic ions, and the resin used was of the chelating iminodiacetic type, Lewatit TP-207. At cyclic steady state, the equipment can split up the wastewater, producing an effluent concentrated in cobalt in the outlet stream of the loading column, and a concentrated stream of copper in the effluent of the elution column. The hydrodynamics and approach to the stationary state of the system were analyzed, and the selective recovery of metals was subsequently tested experimentally. This behavior presents certain similarities with a parametric pumping operation of the system, with the two columns operating at different pH values or temperatures.     

Cyclic Separation Processes

Abstract

This review covers cyclic separation methods used for adsorption, ion exchange, and chromatographic separation processes where the cyclic parameter is a thermodynamic variable which changes the equilibrium distribution coefficients of the solutes. The cyclic methods reviewed include heatless or pressure-swing adsorption, parametric pumping, and cycling zone adsorption. These cyclic techniques have been studied as a possible preparative chromatographic separation method or for continuous production from adsorption or ion exchange columns.     

Separation and Recovery of Silver(I) Ions from Base Metal Ions by Melamine‐formaldehyde‐thiourea (MFT) Chelating Resin

Abstract

Melamine‐formaldehyde‐thiourea (MFT) chelating resin were prepared using melamine (2,4,6‐triamino‐1,3,5‐triazine), formaldehyde, and thiourea and this resin has been used for separation and recovery of silver(I) ions from copper(II) and zinc(II) base metals and calcium(II) alkaline‐earth metal in aqueous solution. The MFT chelating resin was characterized by elemental analysis and FT‐IR spectra. The effect of pH, adsorption capacity, and equilibrium time by batch method and adsorption, elution, flow rate, column capacity, and recovery by column method were studied. The maximum uptake values of MFT resin were found as 60.05 mg Ag⁺/g by batch method and 11.08 mg Ag⁺/g, 0.052 mg Zn²⁺/g, 0.083 mg Cu²⁺/g and 0.020 mg Ca²⁺/g by column method. It was seen that MFT resin showed higher uptake behavior for silver(I) ions than base and earth metals due to chelation.     

Theory of Isotope Separation by Electrochemical Parametric Pumping

Abstract

Electrochemical parametric pumping is a novel separation process in which cycles of reversible electrochemical processes on high surface area electrodes are conducted in synchronization with cycles of solution flow through the separating column. In the present work, isotope separation by electrochemical parametric pumping is studied theoretically. The proposed model is based on the similarity between the parametric pumping and the countercurrent processes and on the division of the separating column to “cells” when dispersion processes are neglected. Steady-state isotopic concentration gradients are calculated and process optimization is performed with respect to system parameters such as the fraction of the isotopes bound to the electrode, the solution displacement volume, and the fraction of the isotopes withdrawn as product. The model may also be applicable to other types of parametric pumping.     

Metal-Metal Chelating Ion-Exchange Processes on 8-Hydroxyquinoline and 8-Hydroxyquinaldine Resins

Abstract

The metal capacity vs pH contours and the separation ratios for copper, zinc, and aluminum have been studied for an oxine-containing, chelating ion-exchange resin. Metal-metal exchange studies on this resin involving the three metals have demonstrated that this is not a simple substitution process, sorption and desorption of the ions being controlled by solution concentration. The sterically hindered ligand, 8-hydroxyquinaldine, incorporated in a resin, demonstrated much greater selectivity for other metals over aluminum and confirmed published solvent extraction data for this ligand.     

Ion Exchange on LIX 65N and Kelex 100 Impregnated Foams

Abstract

The metal capacity vs pH contours and the separation ratios for copper, zinc, and aluminum have been studied for an oxine containing, chelating ion-exchange resin. Metal-metal exchange studies on this resin involving the three metals have demonstrated that this is not a simple substitution process, sorption and desorption of the ions being controlled by solution concentration. The sterically hindered ligand, 8-hydroxyquinaldine, incorporated in a resin, demonstrated much greater selectivity for other metals over aluminum and confirmed published solvent extraction data for this ligand.     

Performance of a synthetic resin for lithium adsorption in waste liquid of extracting aluminum from fly-ash

In this study, we investigated the performance of a synthetic resin for the adsorption of Li from pre-desilicated solution which is the waste liquid produced by extracting aluminum from fly ash. The adsorption kinetics and isotherms of the resin were obtained and analyzed. The saturated adsorption sites of the resin were in agreement with the quasi-second-order kinetic model. Then, the pore diffusion model (PDM) was applied to represent the lithium adsorption kinetics which confirming that the external mass is the limiting step. Moreover, we evaluated the adsorption properties of this resin in fixed-bed mode. We established a feasible extraction process for Li from strong alkaline solutions with low Li concentrations. The process parameters, such as the flow rate, initial adsorption solution concentration, water washing process, desorption agent concentration, and flow rate were studied. The desorption rate of the Li⁺ ions was directly proportional with the concentration of the desorption agent. The time required to accumulate Li decreased as the hydrochloric acid concentration and flow rate increased. Time of the peak appeared increased from 0.5 bed volume (BV) to 2.5 BV as the concentration was increased from 1 to 3 mol·L^-1, and the peak increased from 231 to 394 mg·L^-1. The resin presented good selectivity for Li⁺ ions and could effectively separate impurity ions from the pre-desilication solution.     

Modeling of Size Exclusion Parametric Pumping

Abstract

Sephadex G and Biogel P, well-known gels in size exclusion chromatography, show a large change in their elution behaviors as temperature changes. These phenomena were exploited to separate the binary model solutes Blue Dextran 2000 and nickel nitrate. A series of batch size exclusion parametric pumping experiments in the direct thermal mode was carried out previously to separate binary mixtures. In this paper the experimental separations in batch size exclusion parametric pumping are compared with the predictions of both a local equilibrium model and a dispersion model. The dispersion model, which includes an axial dispersion term, gives a better fit of the experimental data. Experimentally obtained adsorption isotherms are used in the dispersion model to predict the separation performance of nickel nitrate in the Sephadex gel column. The resulting simultaneous partial differential equations are solved by quasilinearization of the equations followed by numerical integration. For both models, all parameters were estimated independently.     

Separation and Recovery of Silver(I) Ions from Base Metal Ions by Thiourea- or Urea-Formaldehyde Chelating Resin

Abstract

In the present work, thiourea-formaldehyde (TF) and urea-formaldehyde (UF) chelating resins have been synthesized and they have been used in the adsorptions of Ag(I), Cu(II), and Zn(II) metal ions by batch and column methods. The effect of initial acidity of Ag(I) solution and the adsorption capacities of TF and UF resins by batch method and the separation of Ag(I) ions from Cu(II) and Zn(II) base metal ions by the column method were examined experimentally. The adsorption capacities of TF and UF resins were found as 58.14 and 47.39 mg Ag(I)/g by batch method and 30.7 and 4.66 mg Ag(I)/g, 0.80 and 0.121 mg Cu(II)/g, and under 0.002 mg Zn(II)/g by the column method, respectively. It was found that Ag(I) ions showed higher affinity towards TF resin than UF resin, compared with Cu(II) or Zn(II) ions, and Ag(I) could be separated more effectively by TF resin from Cu(II)and Zn(II) ions.     

Adsorption equilibrium,kinetics, and dynamic separation of Ca2+ and Mg2+ ions from phosphoric acid-nitric acid aqueous solution by strong acid cation resin

The separation of Ca²⁺ and Mg²⁺ ions from phosphoric acid-nitric acid aqueous solution is very significant for the neutralization process of nitrophosphate fertilizer. This paper studied the adsorption equilibrium, kinetics, and dynamic separation of Ca²⁺ and Mg²⁺ ions by strong acid cation resin, and the effects of phosphoric acid and nitric acid on the adsorption process were investigated. The results reveal that the adsorption process of Ca²⁺ and Mg²⁺ ions in pure water on resin is in good agreement with the Langmuir isotherm model and their maximal adsorption capacities are 1.86 mmol·g^-1 and 1.83 mmol·g^-1, respectively. The adsorption kinetics of Ca²⁺ and Mg²⁺ ions on resin fits better with the pseudo-first-order model, and the adsorption equilibrium in pure water is reached within 10 min contact time, while at the present of phosphoric acid, the adsorption rate of Ca²⁺ and Mg²⁺ ions on resin will go down. The dynamic separation experiments demonstrate that the designed column adsorption is able to undertake the separation of metal ions from the mix acids aqueous solution, but the dynamic operation should control the flow rate of mix acid solution. Besides nitric acid solution was proved to be effective to completely regenerate the spent resin and achieve the recyclable operation of separation process.     

Concentration Effects on Separation Selectivity in Foam Fractionation

Abstract

Removal of cadmium, copper, and nickel ions from aqueous solution by foam fractionation has been studied using a chelating surfactant, 4-dodecyl-diethylenetriamine. The rate of removal is a function of concentration of both metallic ions and surfactant. In the low concentration range for the metallic ions compared to that of the surfactant, the order of removal was found to be Cd²⁺ > Ni²⁺ > Cu²⁺. However, at higher concentrations of ions, the order becomes inverse, Cu²⁺ > Ni²⁺ > Cd²⁺. A selectivity coefficient for the separation of a specified ion from one or more ions using a chelating surfactant is shown to be dependent on the surface tension of the complex and the chelation constants. The relationship between separation selectivity of the removal of the metallic ions and concentration of both surfactant and metallic ions is discussed     

Separation of gold(III) ions from copper(II) and zinc(II) ions using thiourea–formaldehyde or urea–formaldehyde chelating resins

Thiourea–formaldehyde (TF) and urea–formaldehyde (UF) chelating resins were synthesized and these resins were used in the separation of gold(III) ions from copper(II) and zinc(II) base metal ions. In the experimental studies, the effect of acidity on gold(III) uptake and gold(III) adsorption capacities by batch method, and loading and elution profiles of gold(III) ions, gold(III), copper(II), and zinc(II), dynamic adsorption capacities and the stability tests of TF and UF resins by column method were examined. By batch method, the optimum acidities were found as pH 2 and 0.5M HCl, and gold(III) adsorption capacities in the solutions including copper(II) and zinc(II) ions were obtained as 0.088 and 0.151 meq Au(III)/g for UF and TF resins, respectively. On the other hand, by column method, the dynamic adsorption capacities were calculated as 0.109 meq Au(III)/g with TF, 0.023 meq Au(III)/g with UF, 0.015 meq Cu(II)/g with TF, 0.0057 meq Cu(II)/g with UF, and under 6.1 × 10^?5 meq Zn(II)/g with TF or UF. TF resin was more effective in the separation and the concentration of gold(III) ions from copper(II) and zinc(II) ions than UF resin. It was seen that sulfur atoms contributed the gold(III) adsorption comparing with oxygen atoms. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Photo isomerization of cis-cyclooctene to trans-cyclooctene: Integration of a micro-flow reactor and separation by specific adsorption

Liquid-phase adsorption has hardly been established in micro-flow, although this constitutes an industrially vital method for product separation. A micro-flow UV-photo isomerization process converts cis-cyclooctene partly into trans-cyclooctene, leaving an isomeric mixture. Trans-cyclooctene adsorption and thus separation was achieved in a fixed-bed micro-flow reactor, packed with AgNO₃/SiO₂ powder, while the cis-isomer stays in the flow. The closed-loop recycling-flow has been presented as systemic approach to enrich the trans-cyclooctene from its cis-isomer. In-flow adsorption in recycling-mode has hardly been reported so that a full theoretical study has been conducted. This insight is used to evaluate three process design options to reach an optimum yield of trans-cyclooctene. These differ firstly in the variation of the individual residence times in the reactor and separator, the additional process option of refreshing the adsorption column under use, and the periodicity of the recycle flow.     

Adsorption and desorption behaviors of S-adenosyl-L-methionine in a fixed-bed ion-exchange column

S-adenosyl-L-methionine (SAM) is one of most versatile molecules in nature and has wide medical applications. The ion-exchange separation process of SAM of the extract of yeast cells has many advantages over selective precipitation by picrolonic acid. Experiments of the dynamic column process of SAM on JK110 resin were carried out in a fixed-bed ion-exchange column. The effects of different operation parameters on the adsorption and desorption behaviors of SAM were investigated. The results show that the ion-exchange adsorption of SAM is successfully implemented at 2BV/h, 10 g/L, pH 5.0; the adsorbed SAM in the ion-exchanged bed is efficiently desorbed by 0.2 N H₂SO₄ solution at the flow rate of 2BV/h. According to material balance, the recovery yield of SAM for this ion-exchange process is 90.1%. Finally, this ion-exchange process was successfully scaled up to separate SAM at high yield and purity.     

Adsorption mechanism of heavy-metal ion by microspherical tannin resin

The spherical tannin resin (STR) resulting from the reaction between Mimosa (Acacia Mollissima) tannin (condensed-type tannin) and formaldehyde was very porous. The specific surface area of the STR made from 37.5% of tannin was 139.2 m²/g (1 g of the resin in this is wet resin corresponding to 1 g of dried resin). Properties such as specific surface area and average pore radius could be controlled by adjusting the tannin concentration. The apparent activation energy of Cu²⁺ ion adsorption by STR was 3 kcal/mol, and that of Cr⁶⁺ ion was 2 kcal/mol. Since the energy was small, we concluded that the adsorption of metal ions was not influenced significantly by the adsorption temperature. The heat of adsorption for Cu²⁺ ions was only 1.6 kcal/mol, which suggests that the adsorption was a physical phenomenon. It was thought that the diffusion of heavy-metal ions into the porous resin was the rate-determining step of the adsorption since the elution profile of the column method was analogous to the profile of active carbon, which adsorbs physically, the heavy metal ions gradually leaking through the column. The surface and cross section of the STR were observed before and after Cu²⁺ ion adsorption with the scanning electron microscope. The pores of the spherical resin were clogged with adsorbed copper, suggesting that the Cu²⁺ ions were adsorbed during the formation of a multimolecular layer. The adsorption may therefore have been due to physical attractive forces. The rate of adsorption and adsorption isotherms of Cu²⁺ ions from copper salts having various anions was found to vary depending on the type of anion. These phenomena were not thought to be due to the properties of the spherical resin but to differences in the hydration state of copper ions.     

PREPARATION AND ADSORPTION PROPERTIES OF THE POLYSTYRENE RESIN HAVING DIETHYLENETRIAMINE-N,N′- BIS(METHYLENEPHOSPHONATE) GROUP

Styrene-divinylbenzene copolymer beads containing diethylenetriamine-N,N′-bis(methylenephosphonate) group have been synthesized. The adsorption properties, of the present resin for some trivalent and bivalent metal ions have been examined. The selectivity sequence of the present resin at pH lower than 2.0 is as follows: Ga(III)> A1(III)> Sm(III)>Cu(II)>Co(II)>Zn(II)>Ca(II). The present resin reveals remarkable selectivity for the trivalent metal ions. The selective concentration of In(III) Ga(III) and Sm(III) from an acidic aqueous solution has been demonstrated by using a column of the present resin.     

Selective separation and concentration of Pd(II) from Fe(III), Co(II), Ni(II), and Cu(II) ions using thiourea‐formaldehyde resin

Thiourea‐formaldehyde (TUF), a well‐known chelating resin, has been synthesized and it was used in the adsorption, selective separation, and concentration of Pd(II) ions from Fe(III), Co(II) Ni(II), and Cu(II) base metal ions. The composition of the synthesized resin was determined by elemental analysis. The effect of initial acidity/pH and the adsorption capacity for Pd(II) ions were studied by batch technique. The adsorption and separation of Pd(II) were then examined by column technique. FTIR spectra and SEM/EDS analysis were also recorded before and after the adsorption of Pd(II). The optimum pH was found to be 4 for the adsorption. The adsorption data fitted well to the Langmuir isotherm. The maximum adsorption capacity of the TUF resin for Pd(II) ions was found to be 31.85 mg g⁻¹ (0.300 mmol g⁻¹). Chelating mechanism was effective in the adsorption. Pd(II) ions could be separated efficiently from Fe(III), Cu(II), Ni(II), and Co(II) ions using TUF resin. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis,structure, and selective separation behavior of copper‐imprinted microporous polymethacrylate beads

Metal ion‐imprinted polymethacrylate beads with sizes ranging from 100 to 300 μm were prepared by suspension polymerization for the application of selective separation of target metal ions. The metal ion contacting area of the beads was enlarged via pore formation (BET 425 m²/g) using toluene as a porogenic agent. The synthesis of the copper‐imprinted porous beads was verified using FTIR, SEM, and ESCA. Separation capacity and selectivity were investigated carrying out column separation experiments. The selective adsorption behavior of the imprinted beads was significantly affected by flow rate, pH, and metal ion concentration in the solution. Adsorption of the copper ion, the template metal ion, onto the beads was highly selective, compared with other ions such as nickel and zinc, with the selective coefficients at approximately 5–10. The microporous particles possessing such high selectivity has a potential application as novel column packing materials especially requiring high selective efficiency, which is usually not achievable by commercial ion exchange resins. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Selective Recovery of Platinum Group Metals from Spent Automobile Catalyst by Integrated Ion Exchange Methods

Selective recovery of platinum group metals (PGMs), such as Pd, Pt, and Rh, from spent automobile catalyst has been investigated by integrated ion exchange method using dihexyl sulfide (DHS) impregnated resin and commercial weak anion exchange resin (Diaion WA-21) as adsorbents. Batchwise adsorption revealed that the DHS impregnated resin possesses the selective adsorption ability for Pd and WA-21 possesses selectivity for all PGMs, especially Rh. Chromatographic separation of Pd with column packed with DHS impregnated resin can be selectively achieved. The chromatographic separation of Pd and Pt with a column packed with WA-21 is effectively progressed, while that of Rh is insufficient yield due to a slow adsorption rate. Separation of Rh from other two PGMs can therefore be achieved by switching the eluent. Both adsorbents show almost no adsorption abilities for other heavy metals containing in the spent automobile catalyst. Sequential chromatographic operation of the column packed with DHS impregnated resin followed by the column packed with WA-21 can be finally achieved to recover mutual PGM from leaching solution of spent automobile catalyst.