Phragmites karka as a Biosorbent for the Removal of Mercury Metal Ions from Aqueous Solution: Effect of Modification

Table 2

Langmuir isotherm, Freundlich isotherm, and D-R model parameters for the biosorption of mercury ions on the surface of natural P. karka and treated P. karka.

Biosorbent material	Langmuir isotherm	Freundlich isotherm	D-R (Dubinin-Radushkevich) model
Natural P. karka	= 2.1175 + 0.5594	= 0.4506	= + 0.3135
	= 0.978	= 0.987	= 0.8373
	(L/mg) = 0.264	= 2.219	(mg/g) = 1.36
	(mg/g) = 1.787	= 0.429	(kJ/mol) = 1.00
	= (0.274–0.059)	1/ = 0.451
Treated P. karka	= 1.8715 + 0.4409	= 0.5784	= + 0.4599
	= 0.991	= 0.996	= 0.7853
	(L/mg) = 0.235	= 1.729	(mg/g) = 1.58
	(mg/g) = 2.268	= 0.439	(kJ/mol) = 1.118
	= (0.298–0.066)	1/ = 0.578