Fitting parameters of the pseudo-first-order and pseudo-second-order kinetics models that describe Cd(ii) adsorption on different biochars^a.

Biochars	Q exp (mg g−1)	Pseudo-first-order			Pseudo-second order
		Q e (mg g−1)	k 1 (min−1)	R 2	Q e (mg g−1)	k 2 (g mg−1 min−1)	R 2
PC300	24.84	24.43	0.0663	0.8466	25	0.0079	0.9903
PC500	24.10	22.83	0.0352	0.8156	23.92	0.0027	0.9895
PC700	25.00	24.94	0.1293	0.7641	25.06	0.0542	0.9914
SC300	24.83	24.19	0.0673	0.7464	24.75	0.0081	0.9935
SC500	24.91	24.42	0.0769	0.7710	24.81	0.0110	0.9911
SC700	24.96	24.94	0.1694	0.6893	24.94	0.1748	0.9913

^aSpent Pleurotus ostreatus substrate biochar (PC) and spent shiitake substrate biochar (SC).