INTERNATIONAL JOURNAL OF CHEMICAL AND PHYSICAL SCIENCES

Number 6, 2013

1-5
Mössbauer and Thermal Studies of Sodium Ferrite Synthesized from Sodium / Potassium Hexakis (Trimethylacetato) Ferrate (III) Complexes

Authors: LANJEWAR R. B. AND LANJEWAR M. R.

Abstract

View in PDF

Number of views: 418

The thermal analysis of sodium and potassium hexakis (trimethylacetato) ferrate (III) complexes has been carried out in flowing air atmosphere from ambient temperature to 500 oC. Various physicochemical techniques i.e. TGA-DTG, IR and M ssbauer spectroscopy etc have been carried out to characterize the intermediate and end products. After dehydrations, the anhydrous complexes undergo decomposition to yield -Fe2O3 and metal oxalate in the temperature range 200-500oC. A subsequent oxidative decomposition of metal oxalates leads to the formation of respective alkali metal carbonate/oxides in successive stages. Finally, nanosized ferrites have been obtained as result of solid state reaction between -Fe2O3 and fraction of MCO/ MCO3. The temperature of ferrite formation is much lower than possible in the conventional ceramic method.

6-19
Adsorption of Heavy Metal (Cu2+, Ni2+ and Zn2+) from Synthetic Waste Water by Tea Waste Adsorbent

Authors: LOKENDRA SINGH THAKUR, MUKESH PARMAR

Abstract

View in PDF

Number of views: 442

Industrial waste constitutes the major source of various kinds of metal pollution in natural water. There are at least 20 metals which cannot be degraded or destroyed. The important toxic metals are Cu, Ni and Zn. There are numerous methods currently employed to remove and recover the metals from our environment and many physicochemical methods have been proposed for their removal from wastewater. Adsorption is one of the alternatives for such cases and is an effective purification and separation technique used in industry especially in water and wastewater treatments. Cost is an important parameter for comparing the adsorbent materials. Therefore, there is increasing research interest in using alternative low-cost adsorbents. The use of tea waste as the low-cost adsorbents was investigated as a replacement for current costly methods of removing heavy metal ions from aqueous solutions. The experiment results showed that maximum removal of Nickel ion by tea waste is 94% and for Copper & Zinc ion are 89% & 90% respectively at optimum condition.

20-27
Analysis of WASA Supplied Drinking Water Around Dhaka City from Laboratory Analysis Perspective

Authors: MURSHED SABRINA1, ALI MOHAMMAD HASAN2, FARUQUE MOHAMMAD OMOR3, CHOUDHURY SUBHAGATA4

Abstract

View in PDF

Number of views: 434

To investigate the toxic chemicals and microbial pathogens in Dhaka WASA drinking water, 25 sampling area was chosen from different thana of Dhaka city depending on the WASA supplied drinking water. Toxic metals were analyzed by Atomic absorption spectrophotometer, Phenolic compounds were analyzed by HPLC followed by solid phase extraction method and separated Bacteriological quality of water was determined by drop plate method for total bacterial counts and fecal coliform counts. The concentration of toxic metals was below the value of WHO guide line. Pentachlorophenol (PCP), content in all areas exceeded (0.08-0.22mg/L) the maximum level of WHO guide line value (0.001mg/L). Total coliform count (c.f.u/100mL) in the water sample of Bangshal, ShagunBagichaa, Jatrabari, Mohammadpur, Panthapath and Lalbagh areas were <1. Fecal coliform count (c.f.u/100mL) in the water collected from Dhaka University, Dhaka Medical Collage Hospital, SegunBagichaa, Jatrabari, Mohammadpur, Panthapath, Lalbagh and BIRDEM Hospital areas were <1. But total bacterial count in all areas were exceeded (5.0x 103- 5.2x 10 6 c.f.u/100mL) the maximum level of Bangladesh EQ Standard ECR, 1997 Guideline Value 10 c.f.u/100mL. In conclusion the Dhaka WASA drinking water quality was assessed as deteriorate to the existed pathogenic bacterial contamination and in addition of toxic PCP contamination which is alarming to the public health.

28-40
CFD Modeling and Validation of Oxy-Fired and Air-Fired Entrained Flow Gasifiers

Authors: PRAVIN NAKOD

Abstract

View in PDF

Number of views: 445

Environmental drivers like carbon capture and other emission controls are creating a great opportunity for growth and adoption of clean coal technologies. Gasification is one of the more established and matured clean coal technologies and numerical simulations are playing crucial role in its development. Different models and approaches have been proposed and discussed in the literature. In the present work, a step by step approach is proposed to evaluate the fractions of different species as a result of volatile break-up during gasification. The volatile component of a given solid fuel like coal or biomass consists of Carbon, Hydrogen, Oxygen, Nitrogen and Sulfur. Mass of these elements in the evaluated species is balanced with their individual masses in the original solid fuel composition. CFD simulations for ConocoPhillips' EGas technology based gasifier and Mitsubishi Heavy Industries (MHI) research scale two stage air blown gasifierare performed including volatile break-up evaluated using current approach in ANSYS FLUENT 14.5. The reaction rates are computed using the Finite rate/Eddy dissipation reaction model. The Discrete Ordinates radiation model with Weighted Sum of Gray Gas Model (WSGGM) for gas absorption coefficient along with particle radiation interaction is employed in these simulations. The predicted syngas composition and exit temperature are compared with the experimental results. The simulation predictions are within 10% of accuracy compared to the experimental measurements