Table 2. Langmuir and Freundlich Isotherms Parameters for the Adsorption of Phenol Red on OSNP.

	parameters	values
Langmuir	Qm	175.44 mg/g (0.46 mmol/g)
	b	0.04 L/mg (15.05 L/mmol)
	RL	0.26
	R2	0.9977
Freundlich	Kf	10.74 mg/g (0.03 mmol/g)
	1/n	0.47
	R2	0.9392