Volume 3 Issue 2
Authors: Hirokjyoti Bora; Swapnali Hazarika
Abstract: Adsorptive interaction of racemic compound with chiral polymers has been analysed from a study on the adsorption in liquid phase. Adsorption affinity which is expressed as the slope of the linear region of the isotherm for S and R isomer of the racemic compound is found to be different for different chiral polymers used as adsorbent systems. The adsorptive interaction computed from frontier orbital theory seems to correlate well with the experimentally measured adsorption affinity of different isomers. Electronic states of adsorbent and adsorbate were calculated by the semiempirical molecular orbital (MO) method exploiting HOMO/LUMO interaction using PM5 wave function through a geometric optimization method. The experimentally measured adsorption affinity, enthalpy of adsorption for different isomers and selectivity seems to correlate well with the adsorptive interaction energy computed from molecular orbital theory. The result of the investigation provides an implication to design suitable chiral polymer for resolution of racemic compounds.
Keywords: Chiral Polymer; Adsorption Affinity; HOMO; LUMO; Interaction Energy
Authors: Mohamed Magdy Khalil; Rehab Khaled Mahmoud; Saif Elden Babiker
Abstract: The second-stage dissociation constant pK2 of 2-Aminoethanesulfonic acid (taurine) was determined in aqueous solution at different ionic strengths and different temperatures, using pH- metric technique. The thermodynamic quantities (ΔG°, ΔH°, and ΔS°) were studied and discussed. The protonation equilibria for the Taurine in nonaqueous solutions were studied by pH-potentiometry. The dissociation constants, pKa, of taurine and the thermodynamic parameters for the successive and overall protonation processes of taurine were derived at different temperatures in three different mixtures of water and dioxane (mole fractions of dioxane were 0.083, 0.174 and 0.33). Titrations were also carried out in (water + dioxane) with ionic strengths of 0.15, 0.20 and 0.25 mol・dm−3 NaNO3, and the resulting dissociation constants are reported in this paper. A detailed thermodynamic analysis of the effects of organic solvent, dioxane, temperature and ionic strength on the protonation processes of taurine is presented and discussed to determine the factors that control these processes.
Keywords: Protonation Constants; Taurine; Potentiometry; Solution Studies
Authors: Daisuke Kobayashi; Mizuki Mitsuhashi; Tomoki Takahashi; Katsuto Otake; Atsushi Shono
Abstract: Increasing the quantities of nutrient salts from the inflow of wastewater in enclosed waters generate the phytoplankton microcystis, which causes an offensive odor. Thus, establishing a microcystis treatment method is required to improve such aqueous environments. In this study, a new technique that combines microbubbles and ozone was applied to a wastewater treatment process. The effects of microcystis removal on the water samples taken from the outer moat of the Tokyo Imperial Palace were investigated. In addition, a mechanism for a microcystis degradation process using ozone microbubbles is proposed.
Keywords: Microbubbles; Ozone; Microcystis; Waste Water Treatment; Gas Flow Rate