BiFeO3 immobilized within liquid natural rubber-based hydrogel with enhanced adsorption-photocatalytic performance.

Semiconductor materials have shown a good photocatalytic behaviour for the photodegradation of organic pollutants. In this work, maleated liquid natural rubber (MLNR) based hydrogel supported bismuth ferrite (BiFeO3) as photocatalyst was successfully synthesized by crosslinking with acrylic acid (AAc) assisted by the ultrasonication method to study the efficiency for the removal of methylene blue (MB) dye in wastewater. Response surface methodology (RSM) was used to optimize the parameters for adsorption of the methylene blue (MB) dye compound, whereby the effects of the initial concentration of MB and the adsorption time were examined to obtain a quadratic model for the respective hydrogel composite. The prepared composite sample was characterized by Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) and X-ray Diffraction (XRD) analysis. Remarkable improvement for removal of methylene blue (99% removal) was found within 3 h adsorption time with a MLNR/AAc-BiFeO3 hydrogel composite as compared to the pristine hydrogel. A synergistic mode of dye removal by adsorption and photodegradation is proposed. Based on the isotherm and kinetic study conducted, it was found that Freundlich isotherm model and a pseudo second-order kinetic model was best fitted for adsorption of MB dye. The MLNR/AAc-BiFeO3 composite maintains its removal efficiency after 5 cycles without the necessity of post-treatment separation. Therefore, it is crucial to note that the resultant low-cost MLNR/AAc-BiFeO3 hydrogel composite in this study offers excellent potential for water and wastewater treatment applications with improved recyclability and recovery.

Crystal structure of 4-fluoro-N-[2-(4-fluoro-benzo-yl)hydra-zine-1-carbono-thio-yl]benzamide.

In the title compound, C15H11F2N3O2S, the dihedral angle between the fluoro-benzene rings is 88.43 (10)° and that between the central semithiocarbazide grouping is 47.00 (11)°. The dihedral angle between the amide group and attached fluoro-benzene ring is 50.52 (11)°; the equivalent angle between the carbonyl-thio-amide group and its attached ring is 12.98 (10)°. The major twists in the mol-ecule occur about the C-N-N-C bonds [torsion angle = -138.7 (2)°] and the Car-Car-C-N (ar = aromatic) bonds [-132.0 (2)°]. An intra-molecular N-H⋯O hydrogen bond occurs, which generates an S(6) ring. In the crystal, the mol-ecules are linked by N-H⋯O and N-H⋯S hydrogen bonds, generating (001) sheets. Weak C-H⋯O and C-H⋯F inter-actions are also observed.

N-[Eth-yl(2-hy-droxy-eth-yl)carbamo-thio-yl]-3-fluoro-benzamide.

In the title compound, C12H15FN2O2S, the mol-ecule adopts a cis configuration of the fluoro-benzoyl group with respect to the thiono group about their C-N bond. The dihedral angle between the fluoro-benzoyl group and the thio-urea N2CS fragment is 69.60 (11)°. An intra-molecular N-H⋯O hydrogen bond occurs. In the crystal, mol-ecules form chains along the b-axis direction via O-H⋯S and C-H⋯O hydrogen bonds.

N-[Eth-yl(2-hy-droxy-eth-yl)carbamo-thio-yl]-2-methyl-benzamide.

The title compound, C13H18N2O2S, adopts a cis conformation between the methyl-benzoyl and thiono groups across their thio-urea C-N bond. However, the methyl-benzoyl group and N2CS thio-urea moiety are twisted by 15.03 (3)°. In the molecule there is an N-H⋯O hydrogen bond. In the crystal, mol-ecules are linked by O-H⋯O inter-actions, generating chains extending along the c-axis direction.

N-(2-Chloro-5-nitro-phen-yl)-N'-(3-chloro-propion-yl)thio-urea.

The title compound, C10H9Cl2N3O3S, adopts a trans-cis conformation with respect to the position of chloropropionyl and chloronitrobenzene groups respectively, against the thiono about their C-N bonds. The conformation is stabilized by an intra-molecular N-H⋯O hydrogen bond. In the crystal, there is a short Cl⋯Cl contact with a distance of 3.386 (13) Å.

1-(4-Chlorophenyl)-3-(3-chloro-pro-pionyl)thio-urea.

In the title compound, C10H10Cl2N2OS, the mol-ecule adopts a trans-cis conformation with respect to the position of the carbonyl group and the chloro-phenyl groups relative to the thiono group across the C-N bonds. The mol-ecule is stabilized by an N-H⋯O hydrogen bond. In the crystal, mol-ecules are linked by N-H⋯S and C-H⋯O hydrogen bonds, forming zigzag chains along the b-axis direction. C-H⋯π inter-actions are also present.

(4-Fluoro-phen-yl)thio-urea-1,10-phenanthroline (1/1).

Refluxing a mixture of 1,10-phenanthroline, (4-fluoro-phen-yl)thio-urea and cadmium(II) chloride did not produce the expected mixed-ligand complex but formed a co-crystal of the two ligands, C12H8N2·C7H7FN2S. The asymmetric unit consists of two pairs of the co-crystal mol-ecules. In each (4-fluoro-phen-yl)thio-urea mol-ecule, the planes of the N2CS thio-urea units are almost perpendicular to the corresponding fluoro-benzene rings, subtending angles of 76.53 (7) and 85.25 (7)°. In the crystal, N-H⋯N and N-H⋯S hydrogen bonds form inversion dimers from the co-crystal pairs. A weak π-π inter-action between the phenanthroline rings [centroid-centroid distance = 3.7430 (15)Å] is also observed.

4-Chloro-anilinium thio-cyanate.

In the title compound, C(6)H(7)ClN(+)·NCS(-), the benzene ring and the protonated amine and chloro substituents are nearly planar, with a maximum deviation of 0.002 (2) Šfor the N atom. In the crystal, the mol-ecules are linked by N-H⋯N and N-H⋯S hydrogen bonds into a chain along the b axis.

3-Nitro-N-[(pyrrolidin-1-yl)carbothioyl]benzamide.

In the mol-ecule of the title compound, C(12)H(13)N(3)O(3)S, the pyrrolidine ring adopts a half-chair conformation and the dihedral angle formed by the nitro group with the benzene ring is 15.18 (18)°. In the crystal, mol-ecules are linked by N-H⋯S and C-H⋯O inter-molecular hydrogen bonds into chains parallel to the c axis.