ADSORBENTS FOR CD REMOVAL FROM WATER WASTE: A SHORT REVIEW OF THE RECENT DEVELOPMENT - Management of Hazardous Residues Containing Cd - page 27

Activated carbon
prepared from
Phaseolus aureus
hulls

325 15.7 1h 8 72.3 30 [103]

Activated carbon
prepared from
olive stone

790.25 1.85 90min >6 - 20 [113]

Unmodified
activated carbon

725 207.3 120 8 - 30 [106]

Triton X-100-
modified carbon

792.5 232.9 120 8 - 30 [106]

SDS-modified
carbon

805.3 263.2 120 8 - 30 [106]

CTAB-modified
carbon

814.2 279.5 120 8 - 30 [106]

Activated carbon
derived from
bagasse

960 38.03 12h 4.5 - 25 [114]

The biosorption abilities of Rhodococus opacus , a unicellular gram
positive bacterium with amphoteric properties, were studied by Vásquez et al.
[117]. The amphoteric behavior of the cell surface of the R. opacus is caused
by the polysaccharides, carboxylic, lipid and micolic acid groups presented on
the surface cell wall. The Cd 2+ adsorption process followed a pseudo second
order kinetic model, suggesting a chemisorption behavior. The maximum
adsorption capacity was 1.56 mg g -1 .
The Cd 2+ removal from aqueous solution by Sphingomonas paucimobilis ,
a gram negative bacterium, was studied by Tangaromsuk et al. [118]. The
highest percentage of the cadmium removal by live cells of the Sphingomonas
paucimobilis was about 84 % at pH 6, while the highest percentage from pH 5
solutions using dead cells of the Sphingomonas paucimobilis was only 28 %.
Zhou et al. [119] used exopolysaccharide, which is secreted by mesophilic
bacterium ( Wangia profunda ), as a low cost natural adsorbent for removing
Cd 2+ from aqueous solution. FTIR studies indicated that some functional
groups, such as -OH, -COO and C-O-C, were responsible for metal binding.
The monolayer capacity of exopolysaccharide was 116.28 mg g -1 .
The capacity of Eleocharis acicularis biomass to adsorb Cd 2+ from
aqueous solution was evaluated by Miretzky et al. [120]. The maximum
adsorption capacity for Cd 2+ was 33.71 mg g -1 and the efficiency was higher