Determination of iron, cobalt and nickel ions from aqueous media using the alkali modified miswak

This paper describes a simple, rapid, inexpensive method for the preparation of a new

biosorbent based on the modification of miswak fibers by NaOH (AT-Miswak-F). The synthesized

AT-Miswak-F sorbent was utilized as an efficient sorbent for the extraction and preconcentration

of iron group metal ions from various water samples. In this study, it was found that Fe(III), Co(II)

and Ni(II) ions were completely extracted (100%) at pH range of 3–7 and flow rate of 0.3–

2.0 mL min1. Also, the sorption capacity of AT-Miswak-F for Fe(III), Co(II) and Ni(II) are

0.54, 0.24 and 0.15 mmol g1, respectively. Equilibrium was best described by Freundlich isotherm

model (R2 =0.793) and the initial rate constants were 0.077, 0.054 and 0.035 mmol g1 min1,

respectively. Under the optimized conditions, the method exhibited a detection limit of 1.4, 2.8

and 2.1 ng mL1 for Fe(III), Co(II) and Ni(II) ions in water samples with relative standard deviations

of 2.6% (n= 4). The method was successfully applied for the determination of Fe(III), Co(II)

and Ni(II) ions in sea, ground and contaminated water samples.