Redox-mediated polymerization and removal of benzidine from model wastewater catalyzed by immobilized peroxidase

Peroxidase from Momordica charantia was highly effective, active and stable for the oxidation of benzidine from model wastewater. There was no oxidative polymerization of benzidine without any redox mediator. Various experimental parameters were standardized for the maximum oxidation of benzidine by peroxidase. The maximum oxidation of this pollutant was observed in the presence of 0.05 mM phenol, 0.75 mM H2O2 and 0.2 U mL-1 bitter gourd peroxidase (BGP) in a buffer of pH 5.0 at 40°C. Comparative study was performed by soluble as well as surface immobilized bitter gourd peroxidase on Con A layered calcium alginate-starch beads for the degradation of benzidine from model wastewater. Immobilized bitter gourd peroxidase was used for the successful and effective removal of water polluted with benzidine in batch as well as in continuous reactor. The effect of detergents and some water miscible organic solvent was also reported for the oxidation of benzidine from polluted water. Oxidation of benzidine in batch process by soluble and immobilized peroxidase was highly effective and it could remove 72 and 100% benzidine by soluble and immobilized bitter gourd peroxidase, respectively. The reactor filled with immobilized enzyme retained more than 45% benzidine removal efficiency even after 30 days of its continuous operation. The absorption spectra of the treated benzidine exhibited a marked difference in absorption at its λmax as compared to untreated benzidine polluted water.Keywords: Alginate, bitter gourd peroxidase, concanavalin A, removal, immobilizatio

Inhibitive behaviour of corrosion of aluminium alloy in NaCl by mangrove tannin

Anticorrosion potential of mangrove tannins on aluminium alloys AA6061 in NaCl solution has been studied using potentiodynamic polarisation method and scanning electron microscopy (SEM). The study was carried out in different pH of corrosive medium in the absence and presence of various concentrations of tannin. The corrosion inhibition behaviour of the mangrove tannin on AA6061 aluminium alloy corrosion was found to be dependant on the pH of NaCl solution. Our results showed that the inhibition efficiency increased with increasing tannins concentration in chloride solution at pH 6. Treatment of aluminium alloy 6061 with all concentrations of mangrove tannins reduced the current density, thus decreased the corrosion rate. Tannins behaved as mixed inhibitors at pH 6 and reduction in current density predominantly affected in cathodic reaction. Meanwhile, at pH 12, addition of tannins shifted the corrosion potential to more cathodic potentials and a passivating effect was observed in anodic potentials. SEM studies have shown that the addition of tannins in chloride solution at pH 12 reduced the surface degradation and the formation of pits

4,4′,6,6′-Tetra-tert-butyl-2,2′-[1,2-phenyl­enebis(nitrilo­methyl­idyne)]diphenol acetone solvate

In the Schiff base mol­ecule of the title compound, C36H48N2O2·C3H6O, the central benzene ring makes dihedral angles of 46.64 (10) and 49.34 (10)° with the two outer benzene rings, and the two outer benzene rings form an angle of 39.13 (8)°. There are two intra­molecular O—H⋯N hydrogen bonds involving the two hydr­oxy groups, which generate S(6) ring motifs. In the crystal structure, the Schiff base mol­ecules are linked into a chain along the a axis by C—H⋯π inter­actions. The acetone solvent mol­ecules are attached to the chain via C—H⋯O hydrogen bonds

Rust Phase Transformation In The Presence Of Mangrove Tannins.

The transformation of rust in the presence of 5 g L-1 tannins extracted from mangrove barks was studied

2-((E)-{2-[(E)-2,3-Dihydroxy­benzyl­ideneamino]-5-methyl­phen­yl}iminiometh­yl)-6-hydroxy­phenolate

The asymmetric unit of the title Schiff base compound, C21H18N2O4, consists of four independent zwitterions (A, B, C and D) with similar conformations. In each independent mol­ecule, the methyl group is disordered over two positions; the occupancies of the two positions are 0.819 (5) and 0.181 (5) in mol­ecule A, 0.912 (5) and 0.088 (5) in B, 0.734 (5) and 0.266 (5) in C, and 0.940 (6) and 0.060 (6) in D. The dihydroxy­phenyl and the hydroxy­phenolate rings in mol­ecule A form dihedral angles of 17.36 (12) and 13.30 (12)°, respectively, with the central benzene ring, whereas the respective angles for mol­ecules B, C and D are 30.22 (11)/7.46 (11), 35.26 (12)/11.01 (12) and 39.89 (12)/4.29 (12)°. In all independent mol­ecules, intra­molecular N—H⋯O and O—H⋯N hydrogen bonds generate S(6) ring motifs. The four independent mol­ecules are linked into two pairs, viz. A–B and C–D, by inter­molecular O—H⋯O hydrogen bonds. These pairs are linked into a two-dimensional network parallel to the ab plane by C—H⋯O hydrogen bonds. In addition, C—H⋯π and π–π [centroid–centroid distance = 3.5153 (14)–3.7810 (15) Å] inter­actions stabilize the crystal structure

A new insight to the physical interpretation of activated carbon and iron doped carbon material: sorption affinity towards organic dye

To enhance the potential of activated carbon (AC), iron incorporation into the AC surface was examined in the present investigations. Iron doped activated carbon (FeAC) material was synthesized and characterized by using surface area analysis, energy dispersive X-ray (EDX), temperature programmed reduction (TPR) and temperature programmed desorption (TPD). The surface area of FeAC (543 m2/g) was found to be lower than AC (1043 m2/g) as a result of the pores widening due to diffusion of iron particles into the porous AC. Iron uploading on AC surface was confirmed through EDX analysis, showing up to 13.75 wt.% iron on FeAC surface. TPR and TPD profiles revealed the presence of more active sites on FeAC surface. FeAC have shown up to 98% methylene blue (MB) removal from the aqueous media. Thermodynamic parameters indicated the spontaneous and exothermic nature of the sorption processes

6,6′-Di-tert-butyl-2,2′-[1,2-phenyl­ene­bis(nitrilo­methyl­idyne)]diphenol

The mol­ecule of the title Schiff base compound, C28H32N2O2, has a twisted geometry, the dihedral angles between the central benzene ring and the other two benzene rings being 29.12 (14) and 26.01 (14)°. Four intra­molecular C—H⋯O hydrogen bonds and two intra­molecular O—H⋯N hydrogen bonds stabilize the mol­ecular structure. In the crystal packing, mol­ecules are stacked along the a axis and stabilized by π–π inter­actions [centroid–centroid distance = 3.6724 (17) Å]. The crystal studied was found to be a non-merohedral twin, the refined ratio of twin components being 0.374 (5):0.626 (5)

Docking Of Different Enzymes With Quercetin

Flavonoids are a group of polyphenols that widely exists as colourful pigment for fruits,vegetables and herbs. Quercetin is one of the major components of flavonoids

Chlorido{4,4′,6,6′-tetra-tert-butyl-2,2′-[o-phenyl­enebis(nitrilo­methyl­idyne)]diphenolato-κ4 O,N,N′,O′}manganese(III)

The asymmetric unit of the title Schiff base complex, [Mn(C36H46N2O2)Cl], comprises two crystallographically independent mol­ecules. The MnIII centre in each mol­ecule adopts a distorted square-pyramidal geometry. Each MnIII ion is coordinated by the N2O2 atoms of the tetra­dentate Schiff base ligand forming the basal plane and the coordinated chloride anion occupies the apical position. Four bifurcated intra­molecular C—H⋯O contacts stabilize the mol­ecular structure. In the crystal packing, mol­ecules are linked into dimers via inter­molecular C—H⋯Cl contacts and further stabilized by C—H⋯π inter­actions. The crystal studied was a non-merohedral twin, the refined ratio of the twin components being 0.441 (1):0.559 (1)