M.Phil.

Effect of Surfactant on Formation of Hydroxyapatite under Reverse Micelle Condition

2018-12-23T00:00:00Z

Effect of Surfactant on Formation of Hydroxyapatite under Reverse Micelle Condition Yeasmin, Fargana Hydroxyapatite, (HAp), Ca10(PO4)6(OH)2, is a naturally occurring material found in the inorganic component of human bone and enamel. The constituent elements of HAp are primarily calcium and phosphorous, with a stoichiometric calcium to phosphorous ratio is 1.667 capable of promoting intimate bone growth onto femoral implants. The performance, lifespan and quality of the resultant biological coating in vivo is largely dependent on the coating morphology, phase composition, particle size and crystallinity of the powders pre-coating application. The present study focused on preparing Hydroxyapatite nanoparticles (HAp-NPs) through chemical precipitation technique using mixed micelle core as a nanoreactor. Mixed micelle core was used to control morphology such as crystallinity, particle size, particle shape, particle size. Anionic (sodium dodecyl sulphate (SOS)) and cationic (Cetyl trimethyl ammonium bromide (CTAB)) surfactants were used to prepare the mixed micellar core. 18 : 2 ratio of propanol-1 : water system experimentally selected for the formation of reverse micelle for the afore mentioned surfactants. Compositions of both surfactants were varied to control the morphology of HAp-NPs under the same experimental condition. Several techniques such as FTIR, XRD, TOA and SEM were used to characterize the prepared HAp-NPs. Appearance of peaks at various position of the FTIR spectrum shows the PO vibrations of PO;- which are characteristics of hydroxyapatite. In addition, the diffraction pattern of the prepared HAp-NPs are in well agreement with the standard published by the International Centre for Diffraction Data. However, the diffractogram indicates the presence of crystalline as well as amorphous phase. No significant weight loss was observed for the prepared HAp-NPs. SEM result reveals significant morphological variation of the prepared HAp-NPs by changing the amount of two surfactants. Variation of the ratio of surfactants SOS and CT AB allow the variation in the morphology of the prepared particles. This thesis is submitted to the Department of Chemistry, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Masters of Philosophy in Chemistry, December 2018.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 57-61).

Studies on Low cost Bio-Adsorbent in Wastewater Treatment

2018-05-01T00:00:00Z

Studies on Low cost Bio-Adsorbent in Wastewater Treatment Amin, Md. Ruhul Environmental pollution is a great concern in now a day. In modern time, with civilization and industrialization environmental pollution increases. Effluents of textile and dyeing industries pollute the environment directly and indirectly as well. Adsorption is one of the versatile techniques of removing waste. In the present investigation LBS Lima Bean Seed (LBS) (locally known as Rukuri in northern zone of Bangladesh) powder has been used as adsorbent for the removal of three textile reactive dyes, namely Reactive Magenta HB (RMHB), Active Orange P2R (AOP2R) and Reactive Red ME6BL (RRME6BL). It is observed that removal efficiency of RMHB, AOP2R and RRME6BL is high at lower pH (acidic medium). Though AOP2R and RRME6BL adsorbed at pH 2.0 and pH 3.0 respectively but in case of RMHB, it adsorbed relatively at higher pH, 6.0. Effect of concentration, adsorbent dose and contact time on adsorption process was observed. Removal of dyes increases with amount of adsorbent and time. But at in case of lower initial dye concentration dye removal rate was faster. Equilibrium time for the adsorption process was about 120 min. From the isotherm study it is observed that the applicability of the linear form of Langmuir and Freundlich model to LBS was confirmed by the high correlation coefficient R2 > 0.97. This suggests that the Langmuir isotherm and Freundlich models both provide good model of the sorption system. The value of 1/n was lower than 1, (n is greater than 1) indicating that studied dyes were favorably adsorbed by LBS. During the kinetics study it is seen that the plot of pseudo-first order has a high correlation coefficient than the plot of pseudo-second order. It should be mentioned, in both cases the value of R2 is close to the unity. More over the values of amount of adsorbate at equilibrium, qe dramatically differ from the experimental values in case of pseudo-second order. So, the adsorption of tested dyes on LBS is more appropriately followed the pseudofirst order model when compared with that of the pseudo-second order model. Study of Intraparticle diffusion model suggested that Intraparticle diffusion is not only Solo Rate Limiting Step. This thesis is submitted to the Department of Chemistry, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Philosophy in Chemistry, May 2018.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 105-115).

Studies on Volumetric and Viscometric Properties of Nitrobenzene and Alkanols Mixtures

2015-12-01T00:00:00Z

Studies on Volumetric and Viscometric Properties of Nitrobenzene and Alkanols Mixtures Islam, A.K.M. Nasimul Densities and viscosities of binary mixtures of Ethanol + Nitrobenzene (NB), n-Propanol + Nitrobenzene (NB), /so-Propanol + Nitrobenzene(NB), n-Butanol + Nitrobenzene (NB), iso- Butanol + Nitrobenzene (NB), n-Amyl alcohol + Nitrobenzene (NB), iso-Amyl alcohol + Nitrobenzene (NB) and Propylene glycol + Nitrobenzene (NB) have been studied over the entire range of composition (0 < x2 < I) at 298.15- 323.15K with an interval of 5K. The density of alcohols in pure state was found to be in the order of Propylene glycol> n-Amyl alcohol > n-Butanol > n-Propanol > Ethanol and iso-Amyl alcohol> iso-Butanol > iso-Propanol The values of densities of Alkanols + NB at equi-mole fraction systems has been found to be in the order of Ethanol+NB> n-Propanol+NB > n-Butanol+NB > n-Amyl alcohol +NB> Propylene glycol NB and iso-Propanol+NB> iso-Butanol+NB> iso-Amyl alcohol+NB The value of density of Alkanols in NB decreases with the increasing of composition of the Alkanols. The decrease of density with composition of Alkanols can be attributed to solute-solvent interaction. The densities of all Alkanols in pure state increase with the increasing of carbon number which may depend on the molecular weight of alcohols, structural formula and H-bonding of alcohols. The densities decrease regularly with the increasing of temperature. This is due to the thermal agitation and hence the weaker the dipole-dipole interaction or dissociation of H-bonding are occurred. At the 0.5 mole fraction, the density of Ethanol+NB is higher than other higher chain or branched chain Alkanols indicating that the nature of association of NB mostly disrupted in higher or branched chain Alkanols. The excess molar volume, VE for all the systems are positive over the entire range of composition, showing maxima at 0.5-0.8 mole fraction of Alkanols. The values of maxima of VE of Alkanols in NB solutions was found to be in the order of Propylene glycol+NB > n-Amyl alcohol+NB > n-Butanol+NB > n-Propanol+NB > Ethanol+NB and iso-Amyl alcohol+NB > iso-Butanol+N13 > iso-Propanol+NB and iso-Amyl alcohol+NB > n-Amyl alcohol+NB and iso-Butanol+NB > n-Butanol+NB and iso-Propanol+NB > n-Propanol+NB The increasing of VE with carbon chain length of Alkanols may be related to increase of the size of Alkanols. The values of VE for the studied Alkanols increase with the increase of temperature. The observed values of VE for the mixtures have been explained in terms of physical, chemical and geometrical contributions. The viscosity coefficients, ƞ of Alkanols + NB mixtures at six different temperatures have also been determined. The viscosities decrease initially slowly up to ~0.5-0.8 mole fraction of Ethanol, n-Propanol, iso-Propanol, n-Butanol, iso-Butanol, n-Amyl alcohol, iso-Amyl alcohol and Propylene glycol and later on, the viscosity increases sharply until the pure alcohol is reached. The viscosity of NB + Alkanols mixture at 0.5 mole fraction has been found to be in the order of Propylene glycol + NB> n-Amyl alcohol+ NB> n-Butanol >n-Propanol+ NB > Ethanol+ NB and iso-Amyl alcohol+ NB> iso-Butanol + NB > iso-Propanol+ NB and iso- Amy1 alcohol + NB > n- Amy1 alcohol + NB and iso-Butanol + NB> n-Butanol + NB and iso-Propanol + NB > n-Propanol + NB There is a marked decrease in the viscosity with increase of temperature for all the studied alcohols. This ascribed that the Alkanols + NB solutions are less stable at higher temperature. The increasing of viscosity with carbon number of Alkanols or branched chain Alkanols ascribed that the solution resistance increases with the increase of carbon chain length or branched chain. The linear dependence of lnƞ against 1/T shows for the all studied Alkanols + NB mixtures. The branched chain isomers are less stable than linear chain isomer at higher temperature. The excess viscosity, ƞ E values are found to be negative indicating that the Alkanols + NB system are non ideal. Excess viscosities are negative at all the temperatures over the entire range of composition for all the systems with minima occurring between 0.6-0.8 mole fractions. The negative excess viscosity, ƞ E of all the studied Alkanols + NB indicate that the dissociation of components through dispersive forces or steric hindrance. The position of minima virtually does not change remarkably with the variation of temperature. The values of the minima are in the order: Propylene glycol+NB> n-Amyl alcohol+NB > n-Butanol+NB > n-Propanol+NB > thanol+NB and iso-Amyl alcohol+NB> iso-Butanol+NB > iso-Propanol±NB and iso-Amyl alcohol+NB > n - Arnyl alcohol+NB and iso-Butanol±NB > n-Butanol+NB and iso-Propanol+NB > n-Propanol+NB The hydrophobic effect increases with the increasing of carbon chain length of alcohols. This indicates that the ƞ E decreases with the decrease of carbon number. The positive VE, negative ƞ E and negative interaction parameter (ɛ) for the studied Alkanols + NB systems indicate that dispersion force is dominant. Some disruptive force causing volume expansion may be present and it is more than compensated by volume contraction. The thermodynamic parameters such as free energy (∆G*), enthalpy (∆G*), and entropy (∆S*) change of activation for the viscous flow for these systems were examined for the entire range of composition. The free energy (∆G*) were found to be positive in magnitude indicating that the kinetic species involved in forming cavities or holes in the liquid medium is given by the work required in forming the hole against surface tension of the solution. The negative excess free energy, ∆G*E indicate that the strong dispersion force in Alkanols+ NB solution is dominant. The ∆H* values are positive for all the systems indicate that positive work has to be done to overcome the energy barrier for the flow process. The ∆S* values are found to be very small for all the studied systems indicating that the effects of ∆S* are negligible. The excess properties (VE, ƞ E, ∆G*E) data have been fitted by the least square method to the four parameters Redlich-Kister equation and the values of the parameter ai and standard deviation have been reported. The volumetric properties are fully consistent with viscometric and thermodynamic properties. This thesis is submitted to the Department of Chemistry, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Philosophy in Chemistry, December 2015.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 159-166).

Studies on the Application of Antibiotics as External Preservatives of Mango Cultivar of Fazli

2015-06-01T00:00:00Z

Studies on the Application of Antibiotics as External Preservatives of Mango Cultivar of Fazli Khondokar, Md. Arifuzzaman The application of various antibiotics at different concentrations (10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 ppm) for the extension of storage life and quality of fazli mango was studied. The physical properties such as appearance, colour, flavor, taste and texture of all antibiotics treated mangoes were more attractive than those of control one. The storage life of treated mango was prolonged significantly as compared to that of control one. The weight loss control capacity of antibiotics treated mango at 20 ppm of etracycline, amoxicillin 50 ppm, co-trimoxazole 20 and 30 ppm, cefradine 50 ppm, zithromycin 20 ppm was higher than that from control mango. The superior treatment tetracycline 20 ppm, co-trymoxazole 20 & 30 ppm and cefradin 50 ppm reduced the physiological loss in weight 15.79% to 33.62% with respect to control at 14th day. But at 15th day the treatments tetracycline 20 ppm, co-trymoxazole 20 ppm and cefradin 50 ppm reduced the physiological loss in weight 29.34% to 34.33% with respect to control mango. The nutritional qualities of mango were also affected remarkably after treatment with antibiotics. At the last edible stage chemical analysis of mango pulp from antibiotics treated mango at tetracycline 20 ppm, amoxicillin 50 ppm, co-trymoxazole 20 and 30 ppm, ciprofloxacin 20 ppm, cefradin 30 ppm, azithrornycin 20 ppm, cefixime 20 and 30 ppm showed higher pH (5.25, 5.25, 6.20, 6.25, 6.15, 6.32, 5.65, 6.31 and 5.24), total soluble solids (TSS) (12.0%, 11.5%, 15.0%, 19.0%, 18.5%, 17.0%, 15.0%, 14.0% and 13.5%), total sugar (9.79, 6.59, 8.96, 9.77, 11.53, 9.99, 12.39, 9.80 and 10.32 g/100g), protein (0.79%, 1.03%, 0.38%, 0.54%, 0.49%, 0.39%, 0.46%, 0.60% and 0.50%), and iron ( 0.9344, 1.0529, 0.4602, 0.6204, 0.4010, 0.7858, 1.2985, 0.6909 and 0.7572 mg/100g) in comparison to control mango (pH = 5.19, TSS = 10%, total sugar = 10.9 g/l00g, protein = 0.57% and iron = 0.7218 mg/100g). In comparison to control mango it is evident that the antibiotic treated mangoes might be in superior quality as it contains higher vitamin A, vitamin C, total soluble solids, total sugar, iron (Fe) and pH than those of control one. This thesis is submitted to the Department of Chemistry, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Chemistry, June 2015.; Cataloged from PDF Version of Thesis.; Includes bibliographical references (pages 58-63).