4 research outputs found
Biodegradation of Methyl Orange by alginate-immobilized Aeromonas sp. in a packed bed reactor: external mass transfer modeling
Azo dyes are recalcitrant and xenobiotic nature
makes these compounds a challenging task for continuous
biodegradation up to satisfactorily levels in large-scale. In
the present report, the biodegradation efficiency of alginate
immobilized indigenous Aeromonas sp. MNK1 on Methyl
Orange (MO) in a packed bed reactor was explored. The
experimental results were used to determine the external
mass transfer model. Complete MO degradation and COD
removal were observed at 0.20 cm bead size and 120 ml/h
flow rate at 300 mg/l of initial dye concentration. The
degradation of MO decreased with increasing bead sizes
and flow rates, which may be attributed to the decrease in
surface of the beads and higher flux of MO, respectively.
The experimental rate constants (kps) for various beads
sizes and flow rates were calculated and compared with
theoretically obtained rate constants using external film
diffusion models. From the experimental data, the externaL mass transfer effect was correlated with a model JD =
K Re-(1 - n)
. The model was tested with K value (5.7) and
the Colburn factor correlation model for 0.20, 0.40 and
0.60 bead sizes were JD = 5.7 Re-0.15, JD = 5.7 Re-0.36
and JD = 5.7 Re-0.48, respectively. Based on the results,
the Colburn factor correlation models were found to predict
the experimental data accurately. The proposed model was
constructive to design and direct industrial applications in
packed bed reactors within acceptable limits
Design and Synthesis of π-Extended Resveratrol Analogues and In Vitro Antioxidant and Anti-Inflammatory Activity Evaluation
The research on resveratrol (1) has been conducted intensively over a long time due to its proven antioxidant activity and disease-fighting capabilities. Many efforts have also been made to increase these biological effects. In the present study, six new extended aromatic resveratrol analogues containing naphthalene (2) and its bioisosteres quinoline (3 and 4), isoquinoline (5) quinoxaline (6) and quinazoline (7) scaffolds were designed and synthesized using an annulation strategy. The antioxidant and anti-inflammatory activities of these compounds were investigated. All compounds showed better antioxidant activity than resveratrol in ABTS assay. As for the anti-inflammatory test, 5 and 7 exhibited better activity than resveratrol. It is worth noting that nitrogen substitution on the extended aromatic resveratrol analogues has a significant impact on cell viability. Taking the antioxidant activities and NO inhibition activities into consideration, we conclude that isoquinoline analogue 5 may qualify for the further investigation of antioxidant and anti-inflammatory therapy. Furthermore, our study results suggest that in order to improve the biological activity of polyphenolic compounds, extended aromaticity and nitrogen substitution strategy could be a viable method for the design of future drug candidates