Adsorptive Performance of Ni(II) from Aqueous Solutions Using Biochar Made of Phragmites australis by Adding Ammonium Polyphosphate as Flame Retardant

Table 2

Langmuir and Freundlich constants related to the adsorption isotherms of Ni(II) for the BCs samples.

Samples number	Langmuir			Freundlich
	(mg/g)	(L/mg)			(g^−1)
BC-300-0	9.7466	0.0451	0.8714	0.3942	1.4126	0.8888
BC-300-0.25	15.408	0.3169	0.9872	0.1071	9.4480	0.8983
BC-300-0.5	9.4787	0.3748	0.9975	0.0879	6.3414	0.8093
BC-300-1.0	7.1174	0.5569	0.9998	0.0957	4.7841	0.8950
BC-400-0	9.0090	0.2054	0.9917	0.1390	4.7119	0.9102
BC-400-0.25	19.231	0.4948	0.9979	0.1473	10.770	0.9567
BC-400-0.5	15.898	0.4565	0.9983	0.1216	9.6253	0.9766
BC-400-1.0	14.859	0.1760	0.9658	0.1438	7.4076	0.7877
BC-500-0	10.142	0.3728	0.9978	0.1427	5.6305	0.9224
BC-500-0.25	15.528	0.6002	0.9982	0.1328	9.3008	0.8772
BC-500-0.5	15.244	0.8200	0.9964	0.1098	10.046	0.7865
BC-500-1.0	14.025	0.2094	0.9932	0.1920	6.1398	0.9652