Effect of variation of sodium silicate content on microstructure and mechanical properties of thermally cured fly ash-slag based geopolymer composites

Ghosh Kushal and Ghosh Partha

Page No. 1-9

The effect of varying amount of silica content and its effect on microstructure, mechanical properties and reaction products of alkali activated fly ash/slag geopolymer composites has been studied. The percentage of silica content has been varied from 4% to 14% in the form of 6 different mix formulations. All specimens have been subjected to a curing temperature of 60◦C. The mechanical properties e.g. compressive strength, bulk density, apparent porosity and water absorption when measured were found to be increasing with the addition of silica content up to an optimum amount of 12 percent.

Beyond the optimum content if silica was added, it proved detrimental to the development of mechanical characteristics of the specimen. The microstructural features of each of the mix specimens which were studied by SEM, EDAX, XRD and TGA analysis gave corroborative evidence for the change in mechanical behavior.

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Synthesis and Characterization of Silver-doped Aniline-formaldehyde Nanocomposite: Spectroscopic and Microscopic Studies

Chaudhary Jyoti, Tailor Giriraj and Kumar Deepak

Page No. 10-14

In order to get the nanocomposite of silver-doped resin, we treated aniline with dil. HCl and formaldehyde solution (40%) with constant stirring and got polymer metal complex, then we calcinated this complex at 9000C in Muffle furnace for 45 min. The structure and chemical properties of Ag- doped resin were confirmed by IH NMR and IR spectroscopic techniques. The morphological study of this decomposed polymer metal nanocomposite had been done by SEM, AFM and TEM.

Polymer nanocomposites of metals represent an important field for fundamental studies which offer a wide range of engineering and biomedical applications. The prepared polymer Ag-doped aniline formaldehyde nanocomposites are widely used as photosensitive components, catalysts, photo-catalyst and in surface enhanced Raman spectroscopy as well as chemical analysis.

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Characterization and Release Kinetics of Red Ginger Oleoresin Encapsulation based on the effect of Glutaraldehyde Concentration as Crosslinking Agent

Jayanudin, Moh. Fahrurrozi, Sang Kompiang Wirawan and Rochmadi

Page No. 15-25

Glutaraldehyde has been proved as a good cross-linking agent. The aim of this research was to determine glutaraldehyde concentration in toluene and its effect toward a characteristic and release kinetics of red ginger oleoresin microcapsule. The method used for red ginger oleoresin encapsulation was the emulsion crosslinking with glutaraldehyde saturated toluene (GST) as a crosslinking agent. The change of concentration in toluene was affected by the mixing time and the initial concentration of the gluataraldehyde solution. The concentration of glutaraldehyde in the toluene would affect the characterization and release kinetics of the red ginger oleoresin microcapsules. The results showed that the highest concentration of glutaraldehyde in toluene was obtained from the mixing for 180 minutes. The yield of red ginger oleoresin microcapsules was ranging from 66.3 to 95.8% and encapsulation efficiency in range of 62.8 to 81.7%. The average particle sizes were 118.46 ± 21.54-152.47 ± 20.68 m. The microcapsule had perfectly spherical shape with a smooth surface.

Fourier Transform Infrared (FT-IR) analysis showed that crosslinking interaction between chitosan and glutaraldehyde occurred in absorbance of 1582 cm-1. The highest cumulative release was 64.7% and the lowest was 44.36%. The Korsmeyer-Peppas model was the best model for all proposed model (zero model, first model, Higuchi model and Hixon-Crowell model) in this study because it could simulate the release kinetics with the highest linearity value (R2 = 0.93 to 0.96).

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Synthesis, characterization and biochemical studies of metal complexes derived from 2-aminobenzoimidazole derivative

Kokila Rani B., Princess R., Johnson Raja S. and Suman A.

Page No. 26-35

In the present investigations, the bioactive Schiff base was obtained from the refluxing of indole-2-carboxaldehyde and 2-aminobenzoimidazole. The Schiff base was reacted with metal (II) ion giving a chelate. The synthesized Schiff base and its metal (II) chelates were subjected to various physico-chemical techniques such as elemental analyses, molar conductivity, IR, electronic, 1HNMR, EPR and mass spectra. The molar conductance studies of the complexes in DMSO solution at the range of 10-3 M concentration indicate their non-electrolytic nature.

The synthesized chelate acts as a univalent bidentate ligand and the complexes were assigned to have a 1:1 stoichiometry (M:L). A square planar geometry was arrived for the chelates on the basis of electronic absorption spectra of the complexes showing intra-ligand charge transfer and the d-d transitions. Thermal studies showed the presence of bound acetate ions in the metal complexes. The bonding and structures of the complexes are discussed in detail on the basis of the results of the above physico-chemical studies. The antioxidant properties of the compounds were explored by DPPH assay and it was found that the copper complex possesses better free radical scavenging effect than the complexes. Antibacterial activities of these compounds were investigated and were found to be active.

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Copper(II)-Silver(I) Heterobimetallic Complexes of Schiff base Ligands derived from Diethylenetriamine: Synthesis, Surface Morphology and Spectroscopic Studies

Anjum Afreen, Kumar Manoj, Paswan Sikandar and Dubey Raj Kumar

Page No. 36-44

Some new mixed metal complexes of Cu(II)-Ag(I) with linear potentially pentadentate Schiff base ligands derived from diethylenetriamine (DETA) and substituted salicylaldehyde have been synthesized by reacting Schiff base, copper(II) chloride and silver(I) nitrate in 2:2:1 molar ratio(s). The general formula of the complexes was found to be [(sb)2Cu2Ag]NO3, where sbH2= SaldienH2 (N,N’-bis-(salicylidene) diethylenetriamine) 1, VandienH2 (N,N’-bis-(3-methoxysalicylidene) diethylenetriamine) 2 and NapdienH2 (N,N’-bis-(napthlidene)diethylenetriamine) 3.

The elemental analyses, IR, UV, ESR, PXRD and mass spectrometry were used to characterize the isolated ligand and its metal complexes. The surface morphology was determined by SEM analysis. The ligand acts as dibasic with N3O2 pentadentate sites and can coordinate with metal ions to form complexes. The bonding sites are the nitrogen atoms of the azomethine and amine groups and the oxygen atoms of the phenolic groups. Square pyramidal geometry was proposed tentative around copper atom whereas silver atom shows octahedral geometry.

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Decolorization and Bioremediation of Textile Dye Effluent by Bioreactors containing Novel Bacterial Consortium (KDDBO4, KDDBO5, KDDBO8 and KDDB11) and its effect on Phytotoxicity

Karpagam P., Manikandan R. and Selvakumar S.

Page No. 45-49

In this study, fifteen bacteria strains were isolated and identified by using standard microbiological techniques. Among these 15 isolates, four bacterial strains (KDDBO4, KDDBO5, KDDBO8 and KDDB11) were selected for decolourizing of textile dye effluents.

During the treatment period 13%, 37% and 38% of decolourization were observed at 5th, 10th and 15th day respectively. The treated dye effluents and untreated dye effluents were assessed to phytotoxicity study of green gram (Vigna radiate) plant. The shoot and root lengths were increased with treated dye effluents compared to untreated dye effluent treatments. These results indicated that microbial treated dye effluents are able to be used for agriculture irrigation purpose. These results suggested that isolated strains have impressive dye degrading capability and they can be used as excellent bivalents for the bioremediation of toxic dyes.

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Variation in Fe, Mn, Zn and Cu Contents in Common Fruits from Local Market over 13 Years

El Fouly Mohamed M. and Salama Zeinab A.

Page No. 50-55

This study proceeded to investigate Fe, Mn, Zn and Cu contents in fruits between 1998 and 2011. The concentration of micronutrients was examined in nineteen fruits to describe the distinction of micronutrients for 13 years. There were decreases in Fe content in three fruits; increases in eight and no change in four over time.

There were decreases in Mn content in seven fruits; increases in twelve; decreases in five crops in Zn content; increases in four; decreases in Cu content in four crops and increases in fifteen crops. The decrease over time was greatest in Cu followed by Zn, Mn and Fe. Red dates exhibited consistent decreases in metals and cantaloupe displayed consistent increases for all micronutrients.

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Unripe Arecanut Seed Extract as a Natural Corrosion Inhibitor for Mild Steel (MS) in Acid and Alkali Media

Narasimha Raghavendra and Jathi Ishwara Bhat

Page No. 56-64

The inhibition activity of unripe arecanut seed extract for the mild steel (MS) corrosion in both acid and alkali media has been examined through mass loss and Tafel plot methods. The different amounts of unripe arecanut seed extract, contact period and temperature on the protection efficiency of green inhibitor have been examined through mass loss technique. It is observed from weight loss technique that protection efficiency depends on the plant extract amount, time and temperature of the system.

Nature of inhibition of corrosion mode of the unripe arecanut seed extract on the surface of the MS was analysed through electrochemical Tafel curves. Further, morphological studies by Scanning Electron Microscopy (SEM) technique evidenced the existence of tenacious film on MS surface in inhibiting solution.

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Synthesis, characterization and analytical applications of novel electroactive material based on Chromium (III)tungstophosphate

Dogra Pernita, Sharma Harish and Parmar Anju

Page No. 65-76

The simple epoxy-based membrane containing Chromium (III) tungstophosphate was examined as a new sensor for Cu (II) ions. Chromium (III) tungstophosphate has been synthesized by sol-gel method and the characterization of the electro-active sensor was done by FTIR, EDS, SEM and X-Ray Diffraction studies. The potential response was linear within the concentration range of 1.0×10-1–1.0×10-6 M, with a near-Nernstian slope of 21.7±0.5mV/decade and response time of the sensor was less than 8s. The electrode does not show any change in response within a pH range of 2.43-8.79 and it performed well in partially non-aqueous medium up to 30% v/v ethanol, methanol and acetone.

The electro active material had excellent reproducibility and a relatively longer life time of about 6 months. Analytical applicability of membrane sensor was evaluated by using it as an indicator electrode in potentiometric titration of Cu (II) ions against EDTA / Oxalic acid. The electrode was successfully used for the analysis of Cu (II) ions in the sample of Indian brands of green tea and in sea water. The results obtained were in good agreement with that obtained from AAS. The sensor exhibited excellent selectivity for Cu (II) ion over a number of cations like Sm (III), Mn (II), Ni (II), Co (II), Pb (II), La (III), Cu (II), Cd (II), Hg (II) and As (III).

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Comparative study on Extraction process for Pullulan Production from Aureobasidium pullulans

Farjana Begum A. and Ashok kumar A.

Page No. 77-82

Pullulan, an important biodegradable polymer, has been found to be more attractive for commercial and industrial applications in many fields like food science, healthcare, pharmacy due to its material properties. Considering the economics of pullulan production, efforts have been put forward to enhance the production. In this research, microwave assisted extraction of extracellular polysaccharides pullulan from Aureobasidium pullulans is investigated as an alternative to conventional extraction process. The hypothesis to be tested is that the microwave’s selective heating ability leads to the high inter-friction with water molecules near the cell wall; in turn cell wall would be ruptured at different fragmentation and will release the cellular contents.

The yield of pullulan by microwave assisted extraction was 31.42 g/L and 26.16 g/L by conventional extraction respectively. The pullulan yield is higher when compared to conventional extraction process. Effect of microwave extraction time, microwave power on the yield of pullulan was also investigated. This study positively suggests that MW treatment was found to alter activity of microbes and thus EPS production significantly increased.

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Eco-friendly activation of charcoal for purification of water from colored organic pollutants

Ahmed Ibrahim Abd-Elhamid, Ahmed Salah Doma, Aref Mohamed El-syed and El-Refaie Kenawy

Page No. 83-95

This research reports a novel and eco-friendly trend for activation of the charcoal. The wet attrition technique was used for activation of the charcoal (p-AC) and distilled water added as milling medium and activating agent. The obtained active charcoal (m-AC) as well as (p-AC) were characterized using SEM, XRD and FTIR. It is indicated that the properties of m-AC were enhanced such as the reduction of particle size, crystallinity, hydrophilicity and the dispersion in water rather than p-AC. The removal of organic substance (methylene blue (MB) and crystal violet (CV)) from aqueous was used as application to determine the efficiency of the wet attrition technique as activation tool.

The p-AC was found inactive towards removal of MB and CV-dye from the aqueous solution, in contrary, m-AC showed high removal efficient. Consequently, various experimental parameters affecting the removal process such as contact time, dye concentration, pH, m-AC dose, temperature and NaCl dose were investigated. Furthermore, the kinetic studies indicated that the pseudo-second order model was well fitting the adsorption kinetic data for both MB and CV dyes. Moreover, both two dyes MB and CV preferred to adsorb as a monolayer onto the m-AC proved by Langmuir model.

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Surfactant based hybrid ion exchangers

Somya Amita

Page No. 96-106

Hybrid ion exchangers are of recent origin in the field of ion exchange chemistry. They have shown excellent chemical, mechanical and thermal stability conversant to both organic and inorganic counterparts.Very recently, new class of ion exchangers has been studied by combining surfactants and inorganic exchangers. This study highlights the salient features of ion exchangers, various development stages with the modifications with an emphasis on the recent developments in the field of analytical chemistry, particularly surfactant based hybrid fibrous and non-fibrous ion exchangers.

Surfactants or surface-active agents when present in the matrix of inorganic ion-exchangers not only enhance their ion-exchange capacity but also the selective adsorption of metal ions. Therefore, these materials are of great importance in industrial and environmental applications.

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