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

Bulletin of the National Research Centre

Table 7 Rate constants describing Ni 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*	0.39	0.39	0.95**	0.03	0.22	0.58	0.97**	0.06	0.42	0.67	0.98**	0.03
C*	0.30	0.29	0.98**	0.12	0.30	0.30	0.98**	0.12	0.32	0.45	0.99**	0.11
Elovich equation
UC*	2.11	2.53	0.94**	2.22	1.90	3.76	0.94**	2.13	3.30	0.86	0.96**	1.21
C*	1.99	1.50	0.96**	1.87	1.94	1.64	0.95**	1.96	2.13	0.51	0.97**	0.87
Parabolic diffusion equation
UC*	0.18	8.34	0.72**	4.69	0.17	9.09	0.70*	4.42	0.11	4.39	0.75*	0.78
C*	0.17	6.88	0.75**	4.18	0.16	6.94	0.73*	4.22	0.10	3.50	0.75*	2.21
First-order equation
UC*	− 0.34	− 0.33	0.81**	0.27	− 0.43	− 0.47	0.90**	0.34	− 0.26	− 0.30	0.83**	0.28
C*	− 0.45	− 0.38	0.89**	0.24	− 0.45	− 0.36	0.87**	0.28	− 0.28	− 0.35	0.86**	0.24