Bentonite has been subjected to modification through ion-exchange reaction by 1-cetylpyridinum chloride. The modified samples were studied by X-ray diffraction (XRD) technique, Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The basal spacing of unmodified bentonite, determined by XRD was 14.99 Å and after modification it increased up to 16.97 Å and 16.22 Å at 1CEC and 2CEC. The FT-IR studies revealed structural differences between the modified and unmodified bentonite samples. The IR spectra of the modified bentonite showed the C-C stretching bands (1465 and 1462 cm -1 ) and C-H vibrations (near 2926 and 2852; 2854 cm -1 ). Results of the SEM study revealed a tendency towards lump formation and agglomeration of the organomodified clay particles of bentonite. The possibility of the use of new organoclay to adsorb oils from aqueous solution will be explored. Key words:Organoclay; Adsorption; Surfactant; Cation exchange capacity Available online at www.banglajol.info Bangladesh J. Sci. Ind. Res. 50(1), [65][66][67][68][69][70] 2015 *Corresponding author: E-mail: shanta_samina@yahoo.com Materials and methods MaterialsThe materials used for the synthesis of organoclay are bentonite from local market, 1-cetylpyridinum chloride, hydrochloric acid, acetic acid, sodium bicarbonate, ethanol, sodium chloride, sodium dithionite and hydrogen peroxide (30%) from Merck Germany. The surfactant used in this study is 1-cetylpyridinum chloride (CPC) with a purity of >96%. All the chemicals were used as received without any further purification. Organic solvents for the synthesis and characterization were AR grade and were obtained from Merck Germany. MethodBentonite clay sample was dried, grind and stored in a bottle. Purification of clay was done by the method of Tributh and Lagaly (Tributh and Lagaly, 1986). The cation exchange capacity (CEC) of the clay defined as the total amount of exchangeable cations that the soil can adsorb was estimated by Kjeldahl method (Cuadros and Linares, 1995). The CEC of purified bentonite was 110 meq/100g. Organoclay preparation and characterizationPurification of clay was done respectively by sodium-acetate acetic acid buffer, citrate buffer, sodium dithionite, sodium chloride, hydrochloric acid, sodium chloride and at last distilled water.For synthesis, 5g of purified bentonite was dispersed in 400 mL of water under continuous stirring for 1 h. The amount of surfactant added was calculated with the CEC value (110 meq/100 g clay) of bentonite. Desired amount of 1-cetylpyridinium was added to 200 mL of water in the separate container slowly. The reaction mixture was stirred for 4 hours at 80ºC. The resulting product was separated by filtration and washed with distilled water for 3 times. Then the product was washed with ethanol. Synthesized organoclay was dried in an oven at 80ºC for 48 hours and grind into powder. The concentrations of CPC were 1 CEC and 2 CEC of bentonite, respectively and labeled as OM1 and OM2.In Figure 1, chemical structure ...

Due to the increasing demand of cost-effective tiles in Bangladesh, using the locally available raw materials five different batches of tiles have been prepared and their physical properties (firing shrinkage, bending strength, water absorption, bulk density etc.) as well as chemical properties were studied in order to evaluate the quality of the products. The present investigation revealed that various properties of the produced tiles are similar to those present in commercial tiles which are available in the local market.

Considering the demand of ceramic stain colours in Bangladesh, an attempt has been taken to develop iron-chromium-zinc pigment based ceramic stain colour of red-brown shade which could be used as an import substitute material in the local ceramic industries. The desired shade of red-brown stain was synthesized from an equimolar mixture of pure chromium oxide (Cr2O3), iron oxide (Fe2O3) and zinc oxide (ZnO). The developed stain was characterized by X-ray diffraction (XRD) technique. The characteristic of the stain complied with the chemical durability. Moreover, chromium leaching was below the permissible exposure limit which makes it as a promising ceramic stain to be used in our ceramic industries. DOI: http://dx.doi.org/10.3329/bjsir.v48i3.17334 Bangladesh J. Sci. Ind. Res. 48(3), 213-216, 2013

The term composite is a combination of two materials with different physical and chemical properties. When combined, they create a specialised material to do a certain job, for instance, to become stronger, lighter or resistant to electricity. They can also improve strength and stiffness. Metal matrix composites have much improved properties, including high tensile strength, toughness, hardness, low density and good wear resistance compared to alloys or any other metal. Aluminium alloys are becoming important today, especially in the automobile, space and electrical industries. Unfortunately, due to poor wear resistance, aluminium alloy can deteriorate quickly. So the present investigation aims at developing Aluminium 356 alloy (AA356) composites reinforced with 5 wt.% Zirconium Silicate (ZrSiO4) with better wear resistance. The composites have been fabricated using the ‘stir-casting’ method in which the particles were added to molten metal during the stirring process at a rotating speed of 700 rpm. A wear test has been performed on a pin on the disc apparatus. Three process parameters have been considered: normal load, sliding velocity, and sliding distance at three different levels. An experimental plan has been made using Taguchi’s L9 orthogonal array table. The output responses such as wear rate and coefficient of friction have been considered for the investigation. Regression models have been generated for each output response. Using the generated regression models, one can predict the value of the output parameters even without actually performing the experimentation within the range of input factor combinations.