Effect of contamination sources on the rate of zinc, copper and nickel release from various soil ecosystems

Bulletin of the National Research Centre

Table 5 Rate constants describing Zn desorption release from the soils

Soil	Kombora				Abo Rawash				Kafr-Elsheikh
Soil	a	b	R²	SE	a	b	R²	SE	a	b	R²	SE
Modified Freundlich equation
UC*	0.31	0.77	0.93**	0.31	0.21	0.76	0.88**	0.18	0.35	0.79	0.96**	0.17
C*	0.26	0.39	0.90**	0.26	0.26	0.85	0.88**	0.15	0.24	0.61	0.98**	0.23
Elovich equation
UC*	3.89	7.02	0.93**	3.89	2.27	5.10	0.94	4.23	3.95	6.37	0.94**	3.16
C*	2.62	5.86	0.93**	3.62	3.96	6.81	0.94	3.63	2.99	1.57	0.97**	2.46
Parabolic diffusion equation
UC*	0.32	18.02	0.75*	0.32	0.33	16.06	0.71*	8.91	0.26	14.63	0.70*	6.77
C*	0.30	16.07	0.74*	0.30	0.27	16.00	0.70*	7.59	0.24	9.62	0.76*	6.11
First-order equation
UC*	− 0.42	− 0.47	0.81**	− 0.42	− 0.45	− 0.43	0.82**	0.33	− 0.49	− 0.45	0.87**	0.30
C*	− 0.53	− 0.44	0.83**	− 0.43	− 0.52	− 0.50	0.82**	0.38	− 0.52	− 0.35	0.87**	0.30