The advantage of using an available and abundant residual biomass

such as lignin

as a raw material for activated carbons is that it provides additional economical interest to the technical studies.In the current investigation

a more complete understanding of adsorption of Cr(VI) from aqueous systems onto H

3

PO

4

-acid activated lignin has been achieved via microcolumns

which were operated under various process conditions.The practice of using microcolumn is appropriate for defining the adsorption parameters and for screening a large number of potential adsorbents.The effects of solution pH(2-8)

initial metal ion concentration(0.483-1.981 mmol·L

-1

)

flow rate(1.0-3.1 cm

3

·min

-1

)

ionic strength(0.01-0.30 mmol·L

-1

) and adsorbent mass(0.11-0.465 g) on Cr(VI) adsorption were studied by assessing the microcolumn breakthrough curve.The microcolumn data were fitted by the Thomas model

the modified Dose model and the BDST model.As expected

the adsorption capacity increased with initial Cr(VI) concentration.High linear flow rates

pH values and ionic strength led to early breakthrough of Cr(VI).The model constants obtained in this study can be used for the

design of pilot scale adsorption process.