Kinetics of Nickel-Fulvate Reaction in Sewage EffluentsIrrigated Soils

摘要

The kinetics of nickel-fulvate (Ni-FA) reaction with sewage effluents irrigated soils between 0 to 144 h conformed to first order reaction. As predicted by kinetic model, the kinetic constant for the loss of Ni from Ni-fulvate varied from 1105 to 1887mol h~(-1) (av. 1424 mol h~(-1) ) at 15 °C, from 1179 to 1828 mol h~(-1) (av. 1555 mol h~(-1)) at 30 °C and from 1175 to 2317 mol h~(-1) (av. 1709 mol h~(-1)) at 45 °C. These results revealed that rate of Ni-fulvate reaction in soils increased with increasing temperature indicating rates of Ni-FA reaction were temperature dependent. The rate of loss of Ni from Ni-FA by competing ions was positively and significantly correlated with organic carbon (r = 0.512*). The half life of residence of Ni-FA reaction in soils ranged from 3.7x10~(-4) to 6.3x10~(-4) h (av. 4.98x10~(-4) h) at 15 °C, from 3.6x10~(-4) to 5.9x10~(-4)h (av. 4.53x10~(-4) h) at 30 °C and from 3.0 x 10~(-4) to 6.9x10~(-4) h (av. 4.55x10~(-4) h) at 45 °C. The half life time of residence of Ni-FA in soil decreased with increasing temperature. The average diffusion coefficient of Ni increased from 4.58 x 10~(-6) to 7.04x10~(-6) cm~2 sec~(-1) with increasing temperature from 15 to 45 °C indicating that diffusion is temperature controlled reaction.