Rani Bushra

Synthesis, Characterization, and Analytical Applications of a New Composite Cation Exchange Material Acetonitrile Stannic(IV) Selenite: Adsorption Behavior of Toxic Metal Ions in Nonionic Surfactant Medium

A composite cation exchange material acetonitrile stannic(IV) selenite was prepared under different experimental conditions. The ion exchange capacity of the material was improved from 0.75 to 1.83 meq g−1 in comparison to its inorganic counterpart, stannic selenite. The material was characterized on the basis of X-ray, TGA, FTIR, and SEM studies. Ion-exchange capacity, pH titration, elution behavior, and distribution studies were also carried out to determine the preliminary ion-exchange properties of the material. Furthermore, it was investigated that this ion exchange material has a good reusability after 8 times regeneration. The sorption behavior of metal ions was studied in nonionic surfactants namely triton x-100 and tween. On the basis of distribution coefficient studies, several binary separations of metal ions viz- Pb2+-Th4+, Ni2+-Th4+, Ni2+-Zn2+, Cu2+-Ce4+, Al3+-Bi3+, and Al3+Zn2+ was achieved on the packed column of this ion exchange material. The practical applicability of this cation-exchanger was demonstrated in the separation of Th4+ from a synthetic mixture of Th4+, Ca2+, Sr2+, Ni2+, and Mg2+ as well as Cu2+ and Zn2+ from a brass alloy sample. Thus, all the studies suggest that acetonitrile stannic(IV) selenite has excellent potential for the removal of metal ionic pollutant species from aqueous media effectively.

Synthesis and characterization of nano-composite ion-exchanger; its adsorption behavior

A novel organic-inorganic nanocomposite cation-exchanger has been synthesized via sol-gel method. It was characterized on the basis of FTIR, XRD, SEM, TEM, AFM and Raman studies. The structural studies reveal semi-crystalline nature of the material with the particle size ranging from 1-5 nm. Physiochemical properties such as ion-exchange capacity, chemical and thermal stability of composite material have also been determined. Bifunctional behavior of the material has been indicated by its pH titrations curves. The nanocomposite material exhibits improved thermal stability, higher ion-exchange capacity and better selectivity for toxic heavy metals. The ion-exchange material shows an ion-exchange capacity of 1.8 meq g(-1) for Na(+) ions. Sorption behavior of metal ions on the material was studied in different solvents. The cation exchanger was found to be selective for Pb(II), Hg(II) and Zr(IV) ions. The limit of detection (LOD) and the limit of quantification (LOQ) for Pb(II) ion was found to be 0.85 and 2.85 μg L(-1). Analytically important separations of heavy metal ions in synthetic mixtures as well as industrial effluents and natural water were achieved with the exchanger. The practical utility of polyanilineZr(IV)sulphosalicylate cation exchanger has been established for the analysis and recovery of heavy metal ions in environmental samples.

Synthesis, characterization, antimicrobial activity and applications of polyanilineTi(IV)arsenophosphate adsorbent for the analysis of organic and inorganic pollutants

A novel polyaniline based composite cation exchange material has been synthesized by simple chemical route and characterized on the basis of sophisticated techniques. XRD and SEM analyses reveal the amorphous morphology of the material. The partition coefficient studies of different metal ions on the material were performed in DMW and diverse concentrations of HClO4 solutions. On the basis of high Kd values some significant separations of heavy toxic metal ions were achieved from synthetic mixtures as well as tap water samples by using columns of this exchanger. For the optimum adsorption of dye on the material, the effect of various parameters along with Langmuir and Freundlich adsorption isotherm were examined. The observed result of conducting measurement indicates that the material covers semiconductor range. The photochemical degradation of industrial dyes and antimicrobial activity were also investigated which show significant results than some of the known antibiotics. On the basis of good ion exchange capacity along with photochemical degradation and microbial activity, polyanilineTi(IV)arsenophosphate can be considered as an excellent conducting material for the treatment metal ions and degradation of organic pollutants.

A New Hybrid EDTA–Zirconium Phosphate Cation-Exchanger: Synthesis, Characterization and Adsorption Behaviour for Environmental Monitoring

EDTA–zirconium phosphate has been synthesized as a new amorphous hybrid cation-exchanger by the combination of the inorganic ion-exchanger zirconium phosphate and EDTA, thereby providing a new class of organic–inorganic hybrid ion-exchanger with better mechanical and granular properties, a good ion-exchange capacity (2.40 mequiv/g dry exchanger for Na+), good reproducibility, and a higher stability and selectivity towards heavy metal ions. It has been characterized using FT-IR, TGA/DTA, X-ray and SEM methods, in addition to ion-exchange studies such as the determination of its ion-exchange capacity, elution and distribution behaviour, to provide a better understanding of the ion-exchange behaviour of the material. On the basis of distribution studies, the material was found to be highly selective towards Th(IV) and its selectivity was examined by achieving some important binary separations such as Cd(II)–Th(IV), Ni(II)–Th(IV), Hg(II)–Th(IV), Zn(II)–Th(IV), Pb(II)–Th(IV) and Al(III)–Th(IV) by column means, indicating its utility in environmental pollution control in one way or other.

Synthesis, characterization, photolytic degradation, electrical conductivity and applications of a nanocomposite adsorbent for the treatment of pollutants

A new semi-crystalline nanocomposite cation exchanger has been synthesized by the sol–gel method and characterized on the basis of FTIR, XRD, SEM, TEM, TGA and CHNO analysis. The ion-exchange material was synthesized at pH 1.0 and shows an ion exchange capacity of 1.37 meq g−1 for Na+ ions. The composite material exhibits improved ion exchange capacity along with chemical and thermal stability. It can be used at up to 300 °C, with 98% retention of its initial ion-exchange capacity. The conductivity of different samples of composite material was found to be in the semiconducting range, which indicates that the conductivity of the samples is highly dependent on the % of inorganic precipitate. The photochemical degradation of industrial dye was also investigated using this composite. The distribution coefficient studies of metal ions on the material were performed in different concentrations of surfactants (Tween 80, CPC) and on mixtures (solvent + surfactant). On the basis of Kd values the material was found to be selective for Hg(II), Bi(III), Zr(IV) and Pb(II) ions. Some analytically important separations of metal ions in synthetic mixtures and real samples were achieved on the column of this exchanger. The limits of detection for Pb(II), Zn(II) and Hg(II) were found to be 0.32, 0.92 and 0.50 μg L−1 and the limits of quantification were found to be 1.07, 3.08 and 1.69, respectively. Besides the ion-exchanger, polyaniline Ti(IV)As composite material has been successfully applied for the photochemical degradation of industrial dye as well as a conducting material.

A comparative study for the characterization of polyaniline based nanocomposites and membrane properties

Polyaniline (PANI) based novel nanocomposites have been fabricated by using a simple sol–gel method. The experimental conditions including mixing volume ratio of reactants, pH and temperature were established for their synthesis. For the comparative studies, characterizations were performed by using FTIR, TGA, SEM, TEM and XRD analyses. The structural studies reveal the amorphous and semi-crystalline natures with the particle sizes in the nano range. PANI supported nanocomposites exhibit improved conducting behavior, higher ion uptake capacity along with chemical and thermal stability. Membrane potentials of monovalent electrolytes namely KCl, NaCl and LiCl have been studied at different concentrations to examine the relationship between effective fixed charge density and transport properties of the membrane. The present study revealed that among Li+, K+ and Na+ ions, the PANI–Zr(IV)sulphosalicylate nanocomposite membrane shows more cation-selective behaviour towards K+ ions. Effective fixed charge densities were found to follow the order K+ > Na+ > Li+.

Development of PANI/MWCNTs decorated with cobalt oxide nanoparticles towards multiple electrochemical, photocatalytic and biomedical application sites

In the present work, a ternary nanocomposite of Co3O4doped/PANI/MWCNTs (cobalt oxide-doped polyaniline multi-walled carbon nanotubes) was synthesized via the in situ oxidative polymerization of aniline. The composite was fully characterized using instrumental analysis, and further tested for its potential in electrochemical, photocatalytic and biomedical applications. The Co oxide nanoparticles were first synthesized using the sol–gel approach in the presence of starch as a capping agent so as to prevent agglomeration and characterized using Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), EDX, elemental mapping and high-resolution transmission electron microscopy (HRTEM). For the measurement of electrochemical activity, the electrodes were synthesized with MWCNTs and functionalized with a conducting polymer (PANI). For the composite, the Co metal oxide provides a pseudo-capacitance which, in general, improves the performance characteristics of the electrode and has been the focus of many researchers. Further, the specific capacitance of the prepared composite was tested using cyclic voltammetry (CV) and impedance spectroscopy. The capacitive studies reveal that the composite has a synergistic effect and is observed to have the highest specific capacitance of 382 F g−1 run at a scan rate of 10 mV s−1. The composite was also found to have excellent photocatalytic degradation properties and outstanding antibacterial activity against both Gram positive and Gram negative bacterial strains. The minimum MIC (6.25 μg mL−1) and MBC (12.5 μg mL−1) values against E. coli and maximum values against B. amyloliquefaciens (25 and 50 μg mL−1) at fourth dilution were observed. Furthermore, the anticancer efficiency of the composite was tested by making use of two different cancer cell types (MCF-7 and MDA-MB-231) confirming the importance of its biological activity for biomedical applications.

Application of Zr(IV) tungstate for removal of metal ions from aqueous solutions

A heteropolyacid Zr(IV) tungstate-based cation exchanger has been synthesized. An amorphous sample, prepared at pH 1.2 and having a Na+ ion exchange capacity of 0.92 meq g−1, was selected for further studies. Its physicochemical properties were determined using Fourier transform infrared spectrometer, X-ray diffraction, thermogravimetric, and scanning electron studies. To understand the cation exchange behavior of the material, distribution coefficients (K d) for metal ions in various solvent systems were determined. Some important binary separations of metal ions, namely Mg2+–Bi3+, Cd2+–Bi3+, Fe3+–Bi3+, Th4+–Bi3+, and Fe3+–Zn2+, were achieved on such columns. The practical utility of these separations was demonstrated by separating Fe3+ and Zn2+ ions quantitatively in commercial pharmaceutical formulation. The cation exchanger has been successfully applied also for the treatment of industrial wastewater and a synthetic mixture. All the results suggests that Zr(IV) tungstate has excellent potential for the removal of metals from aqueous systems using packed columns of this material.

Immobilization of β-galactosidase on surface modified cobalt/multiwalled carbon nanotube nanocomposite improves enzyme stability and resistance to inhibitor

The present study aimed to work out a high yield procedure for immobilization of Aspergillus oryzae β-galactosidase on polyaniline cobalt multiwalled carbon nanotubes nanocomposite (PANI/Co/MWCNTNC) by physical adsorption and covalent attachment via glutaraldehyde. The binding was confirmed by scanning and transmission electron microscopy along with Fourier transform-infrared spectroscopy. The immobilization yields obtained for adsorbed and cross-linked enzymes were 93% and 97%, respectively. The covalently immobilized enzyme was remarkably more stable at extremes of pH and temperature compared to native and adsorbed enzymes. The Ki values were found to increase ten-folds for covalently immobilized β-galactosidase indicating that this immobilized enzyme was markedly more resistant to galactose inhibition. The covalently attached enzyme retained 92% activity after its 10th successive reuse compared to the adsorbed β-galactosidase which exhibited 74% of its initial activity. Furthermore, no significant change was noticed in the band intensity of pBR322 plasmid when exposed to free and bound nanocomposite. The covalently bound enzyme exhibited superiority in terms of stability and reusability when compared to the adsorbed and native β-galactosidase. The results, presented here demonstrate an efficient method of immobilization of β-galactosidase on PANI/Co/MWCNTNC in order to construct a convenient and novel biosensor for the detection of lactose concentration.

Ion exchangers as adsorbents for removing metals from aquatic media.

Abstract A polyaniline-based composite cation-exchange material was synthesized by way of sol–gel method and studied to explore its analytical and environmental applications. It was characterized by using instrumental analyses [Fourier transform infrared (spectrometer), X-ray, thermogravimetric analysis/differential thermal analysis, standard electron microscopy, and transmission electron microscopy]. Physicochemical studies, such as ion-exchange capacity, pH titrations, and chemical stability, along with effect of eluent concentration and elution, were also performed to exploit the ion-exchange capabilities. pH titration studies showed that the material presents monofunctional strong cation-exchange behavior. This nanocomposite material is semicrystalline in nature and exhibits improved thermal and chemical stability. The partition coefficient studies of different metal ions in the material were performed in demineralised water and different surfactant media, and it was found to be selective for Pb(II) and Hg(II) ions. To exploit the usefulness of the material as an adsorbent, some important quantitative binary separations of metal ions were performed on polyaniline Zr(IV) molybdophosphate columns. This composite cation exchanger can be applied for the treatment of polluted water to remove heavy metals.