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Advisor(s)
Abstract(s)
Industrialization increases the number of heavy
metals released into the environment. Lead ( Pb
2 + ) , nickel
( Ni
2 + ) and chromium ( Cr
6 + ) are among these toxic metals
and cause irreversible e ff ects on ecosystems and human
health due to their bio - accumulative potential. The
decontamination through adsorption processes using
lignocellulosic wastes from agricultural and/or forestry
processes is a viable solution. Hence, this work aimed
at studying the e ff ect of pH on the biosorption of the
metal ions using four di ff erent by - product materials:
walnut shell, chestnut shell, pinewood and burnt pine -
wood. These experiments were conducted with solutions
of the three heavy metals in which the adsorbents were
immersed to measure the rate of adsorption. A range of
pH values from 3.0 to 7.5 was used in the experiments,
and the concentrations were determined by atomic
absorption. The results showed di ff erent behaviour of
the biosorbent materials when applied to the di ff erent
metals. The lead adsorption had an ideal pH in the range
of 5.5 – 7.5 when the walnut shell was used as an adsor -
bent, corresponding to values of adsorption greater than
90%, but for the other materials, maximum adsorption
occurred for a pH of 7.5. For the adsorption of chromium,
the pH was very heterogeneous with all adsorbents, with
optimal values of pH varying from 3.0 ( for chestnut shell )
to 6.5 ( for walnut shell and wood ) . For nickel, the best pH
range was around pH 5, with di ff erent values according to
the lignocellulosic material used. These results indicate that the tested biosorbents have the potential to decon -
taminate wastewater in variable extensions and that by
controlling the pH of the solution; a more e ffi cient
removal of the heavy metals can be achieved.
Description
Keywords
Biosorption Chromium Nickel Lead Chestnut shell Burnt wood
Citation
Cruz-Lopes LP, Macena M, Esteves B, Guiné RPF. (2021) Ideal pH for the adsorption of metal ions Cr6+, Ni2+, Pb2+ in aqueous solution with different adsorbent materials. Open Agriculture, 6(1), 115-123.