Presented by: iram shahzadi
Roll no: 19008






Chrome plating is technique of electroplating a thin layer of chromium
on metal object for decorative and protective purposes
Wastewaters generated from plating process contain high
concentrations of Cr(VI) and low concentrations of soluble forms of
various metal salts.
Due to its high toxicity Cr(VI) must be removed or reduced to Cr(III) in
order to meet the permissible limits to discharge.
Traditional plating wastewater treatments include two main steps: Cr(VI)
reduction and precipitation of Cr(III) and other metal ions as hydroxides.
Electrochemical methods, electro-dissolution of iron and different kind
of electrodes (carbon, graphite copper) are used for Cr(VI) reduction.
wastewater treatment by ion exchange resins is effective and
convenient, they are too expensive to be used by the developing
countries.






Biosorption is the ability of biological materials to accumulate
heavy metals from wastewater through metabolically
mediated or physico-chemical pathways of uptake.
Biosorption uses biomass raw materials that are either
abundant e.g., seaweeds or wastes from other industrial
operations e.g., fermentation wastes.
Biomass derived from several industrial fermentations may
provide an economical source of biosorptive materials.
Coffee is the world second most popular beverage after
water.
The exhausted ground coffee waste, by product of soluble
coffee industry used as biosorbent.
Exhausted coffee has proved to be an efficient sorbent for
the removal of Cr(VI) from both single solutions and binary
mixtures with divalent metals

the aim was to discover
new and low cost
sorbents for Cr(VI)
removal by sorption.
Material






Exhausted coffee
K2Cr2O7(s)
CuCl2·2H2O
HCl
FeCl3
Al2(SO4)3




53.33 g of with 8 L of
samples in a 10 L batch
reactor.
Sampling was done every 5
min at the beginning of the
process.
Experiments persisted
within the interval of 72–
168 h.
Solid particles were
separated by filtration and
the treated wastewater was
stored until it underwent
flocculation/precipitation
treatment.



Alkalization of solution.
Addition of 0-4ml of Al2(SO4)3·18H2O and FeCl3 solution.
After flocs formation, Solids were separated by filtration.
Analytical technique



The pH measured by a pH meter
Chromium and metals concentration in samples was analysed by flame
atomic absorption spectroscopy(FAAS)
Hexavalent chromium was analysed by colorimetric 1,5diphenylcarbazide method by using a sequential injection system (SIA).



Exhausted coffee is highly
efficient to reduce Cr(VI) to
trivalent form.
Fe(III)
present
in
the
effluents partially removed
(15–30%).
Fe(III) and Fe(II) can be
removed by the phenols
and
tannins
of
bio
sorbents,
due
to
the
richness
in
hydroxyl,
carbonyl
and
amine
functional groups of these
compounds





influence of presence of
other metal ions on Cr(VI)
sorption efficiency two
synthetic solution.
S1;- a single Cr(VI)
solution and S2 ;a binary
mixture of Cr(VI), Cu(II).
industrial effluents
matrixes affect rate but
not the amount of Cr(VI)
removed
Cr(III) concentration is
around 2 folds higher
than the one in the
synthetic solutions
Fe(III) can compete with
Cr(III) for sorbent active
sites. .



correlation between Cr(VI)
and Cr(III) concentration in
solution and conductivity and
pH data.
The highest correlation
coefficients (R2> 0.99) were
found between conductivity
and Cr(VI) sorption
experimental data
conductivity or pH or both
parameters can be used to
follow bio-sorption evolution
and as indicator of end of
process.
 The main advantage of using FeCl3 as flocculating agent is its stability
in reaction mixture and good performance for color and turbidity
removal.
 filtration is performed for the removal of sludge and treated water is
discharged in to nearby pounds.




EC proved to be active reducing agent for the
elimination of Cr(VI).
The main advantage of Elimination of Cr (VI)
by bio-sorption method is cost effective, low
electricity consumption and no additional
reducing agent .
the future technology can readily to be
functional for the treatment of chromium
contaminated wastewater
Bio-sorption is eco-friendly process,
suggests the recycling of byproduct instead
of discarding by landfill.

Nuria Fiol, Jordi Poch, Isabel Villaescusa “A new
technology for the treatment of chromium
electroplating wastewater based on bio-sorption
“doi.org/10.1016/j.jwpe.2016.05.002
2214-7144/©
2016 Elsevier Ltd.