Cost-Effective and Eco-Friendly Method for Decolorization of Malachite Green …
279
used during the study were obtained from Merck, Germany. A stock solution of MG
was prepared at a final concentration of 100 mg l
−1 . An inoculum of 1.2% (v/v) was
used.
2.2 Dye Decolorization Study
Dye decolorization study by live cells of K. marina DAGII was performed in UV–Vis
spectrophotometer (TECHCOMP UV 2310) by using the formula given in Eq. 1:
C o − C t
C o
∗ 100 = Dyeremoval%
( 1 )
where C o is the initial concentration of MG (mg l
−1 ) and C t is the final concentration
of MG (mg l
−1 ).
2.3 Malachite Green Removal in Continuous Study
In batch study concentration of decolorized dye by K. marina DAGII cells was
measured at an equal interval of one hour for 8 h. Samples were taken and centrifuged
at 10,000 rpm for 10 min. The supernatant was collected and absorbance was
measured at 617 nm. In column study adsorbent was prepared by immobilizing whole
live cells of Kocuria marina DAGII in alginate with dropwise addition in calcium
chloride solution was done (100 mM, Merck) as described (Bera et al. 2016). Fixed
bed column of 1.5 cm diameter and length 30 cm was used during the study. Treated
MG solution was collected at an outlet at regular time intervals and the concentration was measured at 617 nm. All experiments were carried out at ambient room
temperature (25 °C).
2.4 Optimization of Column Parameters Using RSM
Design-Expert Software (Version 8.0.7.1, Stat-Ease, Minneapolis (USA) was used
for optimization and screening. Based on changing one variable at a time (COVT)
experiment response surface methodology (RSM) was conducted to identify significant factors for an optimal response of MG removal by K. marina DAGII cells. The
four independent factors studied were alginate concentration (A) (2.5–3.5%), column
bed height (B) (10–15 cm), influent flow rate of MG solution (C)(0.5–1 ml min
−1 ),
and initial MG concentration (D) (30–50 mg l
−1 ).The variables were set at fixed levels
279
used during the study were obtained from Merck, Germany. A stock solution of MG
was prepared at a final concentration of 100 mg l
−1 . An inoculum of 1.2% (v/v) was
used.
2.2 Dye Decolorization Study
Dye decolorization study by live cells of K. marina DAGII was performed in UV–Vis
spectrophotometer (TECHCOMP UV 2310) by using the formula given in Eq. 1:
C o − C t
C o
∗ 100 = Dyeremoval%
( 1 )
where C o is the initial concentration of MG (mg l
−1 ) and C t is the final concentration
of MG (mg l
−1 ).
2.3 Malachite Green Removal in Continuous Study
In batch study concentration of decolorized dye by K. marina DAGII cells was
measured at an equal interval of one hour for 8 h. Samples were taken and centrifuged
at 10,000 rpm for 10 min. The supernatant was collected and absorbance was
measured at 617 nm. In column study adsorbent was prepared by immobilizing whole
live cells of Kocuria marina DAGII in alginate with dropwise addition in calcium
chloride solution was done (100 mM, Merck) as described (Bera et al. 2016). Fixed
bed column of 1.5 cm diameter and length 30 cm was used during the study. Treated
MG solution was collected at an outlet at regular time intervals and the concentration was measured at 617 nm. All experiments were carried out at ambient room
temperature (25 °C).
2.4 Optimization of Column Parameters Using RSM
Design-Expert Software (Version 8.0.7.1, Stat-Ease, Minneapolis (USA) was used
for optimization and screening. Based on changing one variable at a time (COVT)
experiment response surface methodology (RSM) was conducted to identify significant factors for an optimal response of MG removal by K. marina DAGII cells. The
four independent factors studied were alginate concentration (A) (2.5–3.5%), column
bed height (B) (10–15 cm), influent flow rate of MG solution (C)(0.5–1 ml min
−1 ),
and initial MG concentration (D) (30–50 mg l
−1 ).The variables were set at fixed levels