Table 2.

Factors and levels of single factor experiment.

Factors	Level
Mass of carrier (g/L)	8	12*	16	20
pH	3	4	5	6	7*	8	9
Metal ions concentration (mmol)	0*	5	10	15	20
Reaction time (min)	5	10	15	30*	45	60	90
Temperature (°C)	27*	40	45	50

^*the levels kept constant when other factors were investigated.