Abstract:
The efficiency of extracellular polysaccharides (EPS)
extracted from Rhizobium BIVr 12 in the adsorption of
Cr’ from industrial wastewater was investigated.
Wastewater containing Cr’ concentrations from a
semiconductor company was obtained. It was then diluted
to 1.0 ppm Cr’* concentration. It was divided into three
sets, each adjusted at different pH level — pH 3, 6 and 9.
Two types of adsorbent were made — sand alone and sand
with EPS. Several 250 mL Erlenmayer flasks containing
100 mL aliquot of wastewater samples were prepared. Each
adsorbent was submerged in the flask containing
wastewater solutions. Flasks were placed in a shaker and
were observed at different time intervals. Collected
samples were then acidified and analyzed using Atomic
Absorption Spectrophotometric (AAS) method. General
Factorial Design and Duncan’s Multiple Range Test
(DMRT) were used to evaluate the data. Results showed
that adsorbent with EPS yielded significant reduction of
Cr" concentrations from the wastewater samples. This
suggests the efficiency of Rhizobium BJVr 12 EPS in the
adsorption process. Maximum reduction of Cr’* using EPS
was achieved after 48 hours at pH 3. The lowest residual
Cr concentration obtained in the experiment was within
the limit set by the Department of Environment and Natural
Resources (DENR).
