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We report the stabilization of ferrofluid in oleic acid synthesized by ultrasonication of nanosized Fe 3 O 4 particle and grafts of poly-dimethylsiloxane (PDMS) with acrylic acid and methacrylic acid. The nanosized polymers were prepared by microwaveassisted copolymerizaion of PDMS chain with 0.029 mol of acrylic acid and 0.023 mol of methacrylic acid. The stability of the prepared materials was characterized by Fourier Transform Infrared (FTIR) spectroscopy, thermal analysis (TG-DTA-DTA), 1 H NMR and transmission electron microscope (TEM). The result indicate that the ferrofluid have nanometric size with high thermal stability. A comparison of both the nanomagnetic fluids has been discussed. The structure of the fluids has been proposed on the basis of the experimental results.

Viscosity ƞ and density ρ of aqueous concentrated perchloric acid 1.0moldm −3 to 9.0moldm −3 were measured at 297.65K. The viscosity data were used to calculate the value of A and B-coefficient of Jones-Dole equation. The value of B-coefficient is positive which suggests the strong ion-solvent interaction in aqueous perchloric acid. The three concentration regions of perchloric acid having value of B-coefficient (measure of ion-solvent interaction or structure making capacity) in the order 1.0 to 4.0moldm −3 < 4.0 to 6.0moldm −3 < 6.0 to 9.0moldm −3 has been proposed.

In the present study, removal efficiency (%) of Rubus ellipticus leaves (REL) as an adsorbent for the removal of Pb(II), Cu(II) and Cd(II) ions was investigated. Different parameters i.e., pH, contact time, temperature, adsorbent dose and initial metal ion concentration were investigated to obtain the optimum adsorption efficiency. At pH 4, a maximum adsorption was 84.6, 80.2 and 74.5 % for Pb(II), Cu(II) and Cd(II) ions, respectively. The maximum adsorption of all the three metal ions obtained at contact time (75 min), initial metal ion concentration (10 mg/L), temperature (25 ºC) and adsorbent dose (5.0 g). The equilibrium adsorption of Pb(II), Cu(II) and Cd(II) ions at different temperature was described by Langmuir, Freundlich and Temkin isotherms. The equilibrium data fitted well the Langmuir adsorption isotherm. Thermodynamic parameters like Gibb′s free energy (ΔGº), enthalpy (ΔHº) and entropy (ΔSº) were also calculated. The calculated parameters indicated that adsorption of Pb(II), Cu(II) and Cd(II) ions onto Rubus ellipticus leaves (REL) was spontaneous (ΔGº < 0), endothermic (ΔGº > 0). The feasibility of the process was evident from the positive value of ΔSº.