The Accumulation of Zn(II) Ions onto Haro River Sand from Aqueous Solutions

摘要

The accumulation of Zn(II) ions onto Haro river sand has been studied using radiotracer (~(65)Zn) and batch techniques, optimizing nature and composition of electrolyte, concentration of Zn(II) ions (2.34 X 10~(-5) - 9.38 X 10~(-4) M), amount of sand (10-2000 mg), shaking time (1-90 min) and temperature (15-55 deg C) to achieve maximum sorption (approx 78 percent). The sorption data follow Freundlich and Dubinin-Radushkevich (D-R) isotherms. Freundlich parameters 1 = 0.39 +- 0.03 and C_m = 0.36 +- 0.11 mmole g~(-1) and D-R constants beta=-0.003l2+-0.00027 kJ~2 mole~(-1) and X_m=54+-10 mumole g~(-1) and E=12.6+-0.5 kJ mole~(-1) have been estimated. The values of DELTA H=48.8+-2.3 kj mole~(-1), DELTA S=-174.5+-7.7 J mole~(-1) K~(-1) and DELTA G=-3.3+-0.2 kJ mole~(-1) at 298 K have been evaluated. Among the ions tested, ascorbate, tartrate, oxalate, citrate, Pb(II), Y(III) and Al(III) reduce the sorption (3-25 percent), whereas Zr(IV) and Cr(III) enhance the sorption significantly. Cd(II), Cr(III), I(I) and Ce(III) have low sorption. This cheaper material appears to have potential applications in analytical separation/preconcentration, in industrial effluent treatment and in water purification.