Ion Exchange Distribution Research Articles

Cellulose acetate-Sn(IV) molybdophosphate: A biopolymer supported composite Exchanger for the removal of selected heavy metal ions

Cellulose acetate-tin(IV) molybdophosphate (CATMP) composite exchanger was prepared by mixing biopolymer celluloseacetate with its inorganic counterpart tin(IV) molybdophosphate (TMP) using sol‑gel method. The physical characterization of the as synthesized exchanger was carried out by FTIR, XRD, BET, TGA-DTG and SEM-EDX techniques. Chemical properties such as ion exchange capacity, chemical stability, pH and distribution behavior were carried out. The average IEC of the composite material, as determined by batch equilibrium, was found to be 2.43 meq/g for Na+ ion; higher than its inorganic counterpart, i.e. 1.41 meq/g. This exchanger was also found to be stable in water, acids and organic solvents, but unstable in basic medium. The distribution study (Kd) of the exchanger in different solvent systems showed promising separation potential of the exchanger towards metal ions of analytical interest from a given mixture of toxic heavy metal ions. The sorption studies revealed that the material was selective for Cr(III) and Cd(II) ions and moderately selective for Co(II) ion in solvents employed in this work. Its selectivity was examined by achieving some important binary separations of metal cations on its column indicating its promising application in environmental pollution abatement.
 
 KEY WORDS: Cation exchanger, Biopolymer, Organic-inorganic hybrid, Sol–gel method, Binary distribution
 
 Bull. Chem. Soc. Ethiop. 2020, 34(2), 259-276
 DOI: https://dx.doi.org/10.4314/bcse.v34i2.5

Rapid and selective removal of Cs+ from water by layered potassium antimony thiostannate

137Cs is radioactive and highly hazardous to human health and the environment and its efficient removal from water is still challenging. In this study, potassium antimony tin sulfide (KATS-2) was synthesized using a hydrothermal method and utilized for the first time for cesium removal from water. KATS-2 showed a high maximum ion exchange capacity (358 mg g−1) and distribution coefficient (1.59 × 105 mL g−1) toward Cs+. In particular, KATS-2 showed rapid ion exchange kinetics and reached the adsorption equilibrium within 5 min with 99% removal efficiency. The adsorption was good at a wide active pH range (1–12) even in extreme alkaline conditions (Kd = 3.26 × 104 mL g−1 at pH 12). The effect of coexisting ions was also investigated, and a high selectivity toward Cs+ was maintained even in artificial seawater (Kd = 3.28 × 103 mL g−1). Powder X-ray diffraction and thermogravimetric analysis demonstrated that KATS-2 was chemically and thermally stable. The results showed that owing to its excellent adsorption performance as well as chemical and thermal stability, KATS-2 is a promising adsorbent for Cs+ removal from contaminated water.

Synergistic effect of organic-inorganic hybrid nanocomposite ion exchanger on photocatalytic degradation of Rhodamine-B dye and heavy metal ion removal from industrial effluents

Present work reports the synthesis of Chitosan-Gelatin @ zirconium (IV) selenophosphate nanocomposite (CH-GEL/ZSPNC) ion exchanger. CH-GEL/ZSPNC was characterized by different characterization techniques using Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FE-SEM), Energy dispersive X-ray spectroscopic studies (EDX), High resolution-transmission electron microscopy (HRTEM), powdered X-ray diffraction (PXRD) and Thermal gravimetric analysis (TGA). Physicochemical properties like ion exchange capacity (IEC), thermal stability, elution behaviour, eluent concentration, pH titration, chemical stability and distribution coefficient (Kd) of (CH-GEL/ZSPNC) ion exchanger were investigated. The ion exchange capacity of the synthesized nanocomposite was improved by one and half order (2.4 mequiv/g) as compare to its inorganic moiety (1.6 mequiv/g) and highest among a number of nanocomposite ion exchangers already reported in the literature. CH-GEL/ZSPNC ion exchanger was found to be thermally stable and retained 58.3% ion exchange capacity (IEC) of its original IEC value at 400 °C. Pb (II) and Cu (II) was found to possess the highest values of Kd. Binary separation of divalent heavy metal ions has been conducted on the basis of Kd values. Photocatalytic degradation of the Rhodamine-B (RD-B) dye was explored with CH-GEL/ZSPNC in the solar radiations. It has been investigated that 84% of the RD-B dye was degraded after 160 min of photo exposure. Photodegradation of the RD-B follows the pseudo-first-order kinetics. Thus, the synthesized CH-GEL/ZSPNC ion exchanger is found to be a superior advanced nanocomposite photocatalyst for environmental remediation of dye pollutants, heavy metal ion removal, the binary separations and possessed tremendous reusability potential.

Chitosan–Gelatin @ Tin (IV) Tungstatophosphate Nanocomposite Ion Exchanger: Synthesis, Characterization and Applications in Environmental Remediation

The present study reported the synthesis of novel organic–inorganic hybrid nanocomposite by incorporating tin (IV) based ion exchanger into the hybrid polymer network of chitosan and gelatin prepared under vacuum for the efficient removal of heavy metal ions and toxic dyes from an aqueous fluid. The physicochemical studies such as ion exchange capacity (IEC), chemical stability, thermal stability, pH titration and distribution behaviour studies were also carried out to determine the cation exchange behaviour of the material. The surface morphology and structural properties were studied by the techniques such as FTIR, FESEM, EDS, TEM and XRD. Distribution studies confirmed the synthesized CG/STPNC had the highest selectivity for Pb2+ ions (85.3 mL/g). Maximum adsorption of methylene blue (82%) was achieved within 240 min at 500 mg of adsorbent dose, 10 mg/L of the initial concentration of dye, pH of 7 and 30 °C of temperature. Adsorption kinetic data fitted well with pseudo-second order rate model with R2 = 0.995. The correlation value 0.95 and favourable RL = 0.21 of adsorption data suggested better fit for Langmuir adsorption. Thus the synthesized nanocomposite ion exchanger was found to be a promising cation exchanger as well as an adsorbent for heavy metal ion and dye removal from textile industrial effluents.

Heavy Metal Separation from Industrial Effluent and Synthetic Mixtures using Newly Synthesized Composite Material

A stable composite cation exchange adsorbent for the treatment of heavy metal ions has been synthesized by sol-gel method and characterized by FTIR, XRD, SEM, TGA and TEM analysis. Ion-exchange capacity, pH titration, elution behavior and distribution studies have been also carried out to determine the primary ion-exchange characteristics of the composite. The material shows exchange capacity of 1.49 meq g-1 (for Na+). The composite material exhibits improved ion-exchange capacity, chemical and thermal stability. It can be used up to 300°C with 87.5% retention of initial ion-exchange capacity. The pH titration data reveals bifunctional behaviour of composite. On the basis of distribution coefficient (Kd), the material has been selective for Cd(II), Ba(II), Hg(II) and Pb(II) ions. A number of important and analytically difficult quantitative separations of metal ions have been achieved using columns packed with this exchanger. The composite cation exchanger has been applied for the treatment of sewage water and synthetic mixture successfully.

Preparation and Properties of Novel Quaternized Metal–Polymer Matrix Nanocomposites

A new class of PANI/Sn(II)SiO3/FCNTs nanocomposite was synthesized by mixing polyaniline into the gel of Sn(II)SiO3 followed by FCNTs (Polyaniline/Sn(II)SiO3/Functionalized Carbon nanotubes). The physico-chemical characterization was carried out by scanning electron microscope, XRD (X-ray Diffraction), FTIR (Fourier Transform Infrared Spectroscopy), ultraviolet–visible spectroscopy, and simultaneous thermogravimetric analysis studies. The ion-exchange capacity (1.2 meq/g) and distribution studies were also determined to understand the ion-exchange capabilities. The DC electrical conductivity studies revile it in the range of 3–5 × 10−3 S/cm. On the basis of distribution studies, ion-selective membrane electrode was designed for Hg(II). The analytical utility of this membrane was established by using it as an indicator electrode in electrometric titrations.

Synthesis, characterization and analytical application of cellulose acetate-tin (IV) molybdate nanocomposite ion exchanger: binary separation of heavy metal ions and antimicrobial activity

A novel cellulose acetate-tin (VI) molybdate nanocomposite (CA/TMNC) exchanger was synthesized by sol-gel method and characterized using techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and thermal analysis. Transmission electron microscopy (TEM) results indicated the formation of particles of nanodimensions. The ion exchange capacity, pH titration, elution behavior, and distribution coefficient were also investigated. CA/TMNC showed enhanced ion exchange capacity as compared to its inorganic counterpart. The distribution coefficient (K d ) values for different toxic heavy metal ion such as Pb+2, Cd+2, Mg+2, Zn+2, Co+2, Cu+2, Mn+2, Cr+3, Ni+2, and Fe+2 has been studied in double-distilled water by batch process. On the basis of K d values, four binary separation of the metal ions have been achieved on the column of CA/TMNC. The material is found to be selective for Pb2+ and Cd2+ ions; about more than 94 % of Pb2+ and 93 % of Cd2+ ions were recovered in each separation. The antibacterial activity of CA/TMNC was explored against Escherichia coli. The results confirmed the bacteriostatic nature of the CA/TMNC.

A biopolymer-based hybrid cation exchanger pectin cerium(IV) iodate: synthesis, characterization, and analytical applications

Pectin cerium(IV) iodate (PcCeI) and cerium(IV) iodate (CeI) cation ion exchange materials were synthesized via sol–gel methods. The materials were characterized by using Fourier transform infrared spectroscopy, X-ray diffractometer, thermogravimetric analysis, and scanning electron microscopy. The ion exchange capacity (IEC), thermal stability, distribution coefficient (Kd), and pH titrations were investigated to recognize the cation exchange behavior of the materials. The IEC of pectin-cerium(IV) iodate (PcCeI and cerium(IV) iodate CeI were reported as 1.80 meq/g and 0.92 meq/g, respectively. The higher distribution coefficient values of 250.01 and 219.14 mg/L confirmed the selectivity of pectin-cerium(IV) iodate hybrid ion exchanger for As3+ and Zn2+. The antibacterial activity of synthesized ion exchangers was explored for E. coli bacteria and observed relatively higher for PcCeI as compared to CeI.

Sorption of the antitumor drug prospidinum on microgels of polysaccharide phosphates

The intermolecular interaction of prospidinum with gel-forming dextran and starch phosphates has been studied. The sorption equilibria have been studied for cytostatic and the biodegradable hydrogels of polysaccharide phosphates. The concentration coefficients of ion exchange equilibrium and distribution coefficients of prospidinum have been calculated at different degrees of microgel phase filling with the cytostatic, and the relations between the coefficients and the degree of hydrogel swelling have been determined. The ion-exchange and nonexchange contributions to sorption values have been found. The analysis of the distribution coefficients has demonstrated that the concentration of prospidinum sorbed through the nonexchange mechanism is higher than its concentration in an external solution due to the van der Waals interactions between prospidinum cations and macromolecules of polysaccharide phosphates. The Na form of polysaccharide phosphates is the optimal carrier for prospidinum, because this form has a higher density of the total negative charge than their H form has.

Synthesis of silver embedded poly(o-anisidine) molybdophosphate nano hybrid cation-exchanger applicable for membrane electrode.

Poly(o-anisidine) molybdophosphate was expediently obtained by sol-gel mixing of Poly(o-anisidine) into the inorganic matrices of molybdophosphate, which was allowed to react with silver nitrate to the formation of poly(o-anisidine) molybdophosphate embedded silver nano composite. The composite was characterized by Fourier Transform Infrared Spectroscopy, X-ray powder diffraction, UV-Vis Spectrophotometry, Fluorescence Spectroscopy, Scanning Electron Microscopy/Energy-dispersive X-ray Spectroscopy and Thermogravimertic Analysis. Ion exchange capacity and distribution studies were carried out to understand the ion-exchange capabilities of the nano composite. On the basis of highest distribution studies, this nano composite cation exchanger was used as preparation of heavy metal ion selective membrane. Membrane was characterized for its performance as porosity and swelling later on was used for the preparation of membrane electrode for Hg(II), having better linear range, wide working pH range (2–4.5) with fast response in the real environment.

Styrene–tin (IV) phosphate nanocomposite for photocatalytic degradation of organic dye in presence of visible light

Styrene–tin (IV) phosphate nanocomposite (ST/TPNC) ion exchanger was used as efficient photocatalyst for the degradation of methylene blue dye from aqueous system in the presence of solar light. ST/TPNC exhibited a high efficiency in heterogeneous photocatalytic process for the removal of MB from the water system. The degradation efficiency after 2h illumination was 80%. The degradation of MB follows the pseudo-first-order kinetics with rate constant 0.00702min−1. The nanocomposite ion exchanger was explored for its ion exchange capacity, pH titration, elution behavior, elution concentration and distribution coefficient (Kd). ST/TPNC exhibited a higher ion exchange capacity (1.83meg/g) compared to its inorganic counterpart (0.55meg/g). ST/TPNC was characterized using some techniques such as Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and thermogravimetric analysis (TGA).

Synthesis, characterization and antibacterial activity of cellulose acetate–tin (IV) phosphate nanocomposite

Cellulose acetate–tin (IV) phosphate nanocomposite (CA/TPNC) was prepared using simple method at 0–1 pH. The nanocomposite ion exchanger was characterized using some techniques such as Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and thermogravimetric analysis (TGA/DTA/DSC). The nanocomposite material was explored for different properties such as ion exchange capacity, pH titration, elution behavior, thermal stability, and distribution coefficient. The ion exchange capacity of CA/TPNC was found higher compared to their inorganic counterpart. The distribution coefficient studies of nanocomposite ion exchanger were investigated for different metal ions. On the basis of distribution coefficient studies CA/TPNC material was found more selective for Cd2+ and Mg2+. CA/TPNC ion exchange was explored for antibacterial activities against E. coli bacteria.

A new way of synthesis nanohybrid cation-exchanger applicable for membrane electrode

A novel polymeric composite namely, PANI-PW/Ag (silver doped polyaniline phosphotungstate) was expediently obtained by sol-gel method. PANI-PW/Ag was characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, UV–vis spectrophotometry, scanning electron microscopy, and thermogravimertic analysis. On the basis of ion exchange capacity and distribution studies, PANI-PW/Ag, highly selective and sensitive to Cu(II), was used for the preparation of ion selective membrane for Cu(II). The electrode exhibits good potentiometric response for Cu(II) over a wide concentration range (1.0 × 10−1−5.0 × 10−6 mol) with Nernstian slope of 27.8 mV per decade. Response time of the electrode is 9 s and it could be used for a period of 3 month and exhibits good selectivity toward Cu2+ in comparison to alkali, alkaline earth, transition, and heavy metal ions, with no interference caused by other heavy metals. POLYM. COMPOS., 35:1436–1443, 2014. © 2013 Society of Plastics Engineers

Pectin–cerium (IV) tungstate nanocomposite and its adsorptional activity for removal of methylene blue dye

Pectin–cerium (IV) tungstate composite (Pc/CT) has been prepared by sol gel method at room temperature. The composite ion exchanger has been characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and Fourier infrared spectroscopy. The ion exchange capacity, pH titrations, thermal stability and distribution coefficient of composite ion exchanger were investigated. The Na+ ions exchange capacity of the Pc/CT has been observed higher (1.4 meq g−1) as compared to its inorganic counterpart (0.8 meq g−1). Pc/CT composite ion exchanger was thermally stable and retained about 60 % of its ion exchange capacity up to 400 °C. The distribution study has inferred more selective the Pc/CT for Zn2+ as compared to other metal ions. The adsorption efficiency of Pc/CT was tested for methylene blue removal dye from aqueous phase. The removal of dye followed pseudo-second-order kinetics.

Preparation and characterization of 5-sulphosalicylic acid doped tetraethoxysilane composite ion-exchange material by sol–gel method

In this manuscript, we report the preparation and characterization of sulphosalicylic doped tetraethoxysilane (SATEOS), composite material by sol–gel method as a new ion exchanger for the removal of Ni(II) from aqueous solution. The fine granular material was prepared by acid catalyzed condensation polymerization through sol–gel mechanism in the presence of cationic surfactant. The material has an ion exchange capacity of 0.64mequiv./g(dry) for sodium ions, 0.60mequiv./g(dry) for potassium ions, 1.84mequiv./g(dry) for magnesium ions, 1.08mequiv./g(dry) for calcium ions and 1.36mequiv./g(dry) for strontium ions. Its X-ray diffraction studies suggest that it is crystalline in nature. The material has been characterized by SEM, IR, TGA and DTG so as to identify the various functional groups and ion exchange sites present in this material. Quantum chemical computations at DFT/B3LYP/6-311G (d,p) level on model systems were performed to substantiate the structural conclusions based ion instrumental techniques. Investigations into the elution behaviour, ion exchange reversibility and distribution capacities of this material towards certain environmentally hazardous metal ions are also performed. The material shows good chemical stability towards acidic conditions and exhibits fast elution of exchangeable H+ ions under neutral conditions. This material shows remarkable selectivity for Ni(II) and on the basis of its Kd value (4×102 in 0.01M HClO4) some binary separations of Ni(II) from other metal ions are performed.

Cellulose acetate–zirconium (IV) phosphate nano-composite with enhanced photo-catalytic activity

Cellulose acetate-zirconium (IV) phosphate nanocomposite (CA/ZPNC) was synthesized by sol-gel technique at pH 0-1 and was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, Fourier infrared spectroscopy (FTIR) and thermal analysis (TGA/DTA/DSC). Ion exchange capacity, pH titration, elution concentration, elution behaviour, thermal stability and distribution coefficient were investigated to explore ion exchange behaviour of CA/ZPNC. The nanocomposite showed an ion-exchange capacity of 1.4 mequiv. g(-1) for Na(+) and was highly selective for Pb(2+) and Zn(2+) over many other metal ions. The photocatalytic activity of the CA/ZPNC was explored for degradation of a model Congo red dye from aqueous phase. 90% of dye was removed in 60 min of irradiation. Simultaneous adsorption and photocatalysis had synergetic effect on dye degradation.

Synthesis and Characterization of Bismuth (III) Tungustosilicate A New Inorganic Cation Exchanger

In the present work, synthesis of a new inorganic Cation exchanger is done & the synthesized exchanger is characterized by determining its ion exchange capacity, thermal stability, chemical stability and distribution studies. It has also been characterized by IR, TGA and XRD studies. The state of the exchanger is found to be semicrystalline. The ion exchange capacity of the synthesized ion exchanger has been found 0.80 meq/g. The exchanger has a high stability against temperature and chemicals. Kd Values were also calculated. The inorganic ion exchanger has the maximum Kd value for zinc and minimum for lead ions. As an application part binary separations and removal of toxic metal ions were done.

Thermal Studies and Analytical Applications of a Newly Synthesized Composite Material “Polyaniline Stannic Molybdate”

Polyaniline stannic molybdate—an organic-inorganic composite material, was prepared via sol-gel mixing of organic polymer polyaniline into matrices of inorganic precipitate of stannicmolybdate. The composite material synthesized at pH 1.2 showed an ion exchange capacity 1.8 meq/g for Na+ ions. Ion exchange capacity, pH titration and distribution studies were carried out to determine the preliminary ion exchange properties of the material. The distribution studies showed the selectivity of Hg(II) ions by this material. The effect of temperature on the ion exchange capacity of the material at different temperatures had been studied. The sorption behavior of metal ions was also explored in different surfactant media.

Simultaneous sorption recovery of platinum and rhodium from sulfate–chloride solutions

The present work is devoted to simultaneous ion exchange recovery of platinum(II, IV) and rhodium(III) from sulfate–chloride solutions, freshly prepared and stored over 3months, on commercial macroporous anion exchangers with different chemical structures. The sorption was carried out from solutions with 2.0; 0.1 and 0.01mol/L HCl and H2SO4. The initial concentrations of platinum and rhodium in contacting solutions were 0.05–5.0mmol/L. Sorption and kinetic properties of selected anion exchangers were investigated and the basic parameters of ion exchange capacity, recovery, distribution coefficients, separation factors, process rate, diffusion coefficients and half-exchange times were calculated. It was shown that the anion exchangers possess high sorption ability towards platinum and rhodium during their recovery from freshly prepared and stored sulfate–chloride solutions. The optimal molar ratio of hydrochloric and sulfuric acids was determined as 1:1. It was shown that freshly prepared sulfate–chloride systems have the same efficiency during simultaneous Pt/Rh recovery as chloride solutions. In case of stored systems, the sulfate–chloride solutions compare favorably with chloride ones.

Development of nano-composite adsorbent for removal of heavy metals from industrial effluent and synthetic mixtures; its conducting behavior

A semi-crystalline stable composite cation exchange adsorbent for the treatment of heavy metal ions has been synthesized at pH 1.0 by sol–gel method which was characterized by FTIR, XRD, SEM, TGA and TEM analysis. Ion exchange capacity, pH titration, elution behavior and distribution studies were also carried out to determine the primary ion-exchange characteristics of the material. The material shows exchange capacity of 1.47meqg−1 (for Na+ ions). The composite material exhibits improved ion-exchange capacity, chemical and thermal stability. It can be used up to 200°C with 88% retention of initial ion-exchange capacity. pH titration data reveal its bifunctional behavior. The distribution coefficient values (Kd) of metal ions have been determined in various solvent systems. On the basis of Kd values the material was selective for Ba(II), Hg(II), and Pb(II) ions. The limit of detection (LOD) and the limit of quantification (LOQ) for Pb(II) was found to be 0.97 and 2.93μgL−1, respectively. A number of important and analytically difficult quantitative separations of metal ions have been achieved using columns packed with this exchanger. The composite cation exchanger is applied for the treatment of sewage water and synthetic mixture successfully and can be used as a conducting material.