Photocatalytic Degradation Studies of Organic Dyes over Novel Cu/Ni Loaded Reduced Graphene Oxide Hybrid Nanocomposite: Adsorption, Kinetics and Thermodynamic Studies.

Nowadays, for environmental remediation, photocatalytic process involving graphene-based semiconductors is considered a very promising oxidation process for water treatment. In the present study, nanocomposite (Cu/Ni/rGO) has been synthesized by Dypsis lutescens leaf extract. Characterization of the sample was carried out by UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Different parameters like contact time, nanocatalyst amount, dye concentration, effect of temperature. and pH factor were optimized to examine the maximum removal efficiency for dyes rhodamine B and alizarine R with and without visible light source. In both cases, i.e., with or without light, maximum removal was observed at 20 mg of nanocatalyst for 5 ppm concentration of both dyes at 45 °C temperature and pH 10 for rhodamine B and pH 4 for alizarine R, respectively with a 20 min contact time. Maximum removal of dyes 93% rhodamine B and 91% alizarine R were observed under a tungsten lamp as compared to without a tungsten lamp, i.e., 78% of RhB and 75% of AR from mixture solution of these dyes. To assess the rate of reaction, spontaneity, and nature of reaction thermodynamics, kinetics and adsorption isotherms were studied. Thermodynamic values indicated that both dyes depicted endothermic and spontaneous degradation processes. Isotherm data fitted best to a Freundlich isotherm, while results of kinetic studies of both dyes followed the pseudo 2nd order kinetic equation. In the end, scavenging radical studies concluded that hydroxyl radicals were the main active specie involved in the photocatalytic degradation process, and regeneration experiments resulted that Cu/Ni/rGO nanocomposites were re-utilized for about four times.

Sulfate and phosphate ions removal using novel nano-adsorbents: modeling and optimization, kinetics, isotherm and thermodynamic studies.

Many compounds containing sulfur and phosphorous are present in wastewater of various industries like food processing, paper making, etc. The higher level of phosphate and sulfate ions causes many problems in everyday life. Based on this, nickel monometallic and nickel-cobalt bimetallic nanoparticles were synthesized using leaves extract of Coix lacryma-jobi L. and applied for sulfate and phosphate ions removal. UV-Vis. spectroscopy, fourier transformed infrared spectroscopy; scanning electron microscopy; X-ray diffraction, and energy-dispersive X-ray spectroscopy were used as characterizing techniques for synthesized nanoparticles. UV spectra for Ni nanoparticles showed the absorption band in the 380-400 nm range, while for Ni-Co bimetallic nanoparticles was noticed at 396 nm and 513 nm. Different functional groups were observed in FTIR spectra of leaves extract which acted as reducing and capping agents to form stable NPs. Different factors like adsorbent dosage, pH, temperature, adsorbate concentration, and time were optimized for maximum removal of sulfate and phosphate anions. The antioxidant potential of prepared nanoparticles was assessed by three different methods. The kinetics, thermodynamics, and adsorption isotherms were also studied for these ions removal. In the current study, the green approach was easy, time-saving and proved to be beneficial to remove sulfate and phosphate anions from wastewater.

The leaves extract of Coix lacryma-jobi L. were employed for the synthesis of nickel monometallic and nickel-cobalt bimetallic nanoparticles and employed for the removal of sulfate and phosphate ions from aqueous solution. Antioxidant potential of biosynthesized nanoparticles was also assessed. Hence, the biosynthesized nanomaterial found to be novel adsorbent for removal of sulfate and phosphate from waste water. This research work has not been previously reported in literature.

Antioxidant and lipoxygenase inhibiting new iridoid glucosides from Caryopteris odorata.

The phytochemical investigation of the ethylacetate-soluble fraction of Caryopteris odorata (Ham. ex Roxb.) led to the isolation of four new iridoid glucosides (1-4): 8-O-trans-cinnamoyl caryoptoside (1), 8-O-trans-cinnamoyl shanzhiside methylester (2), 8-O-trans-cinnamoyl mussaenoside (3) and 8-O-cafeoyl massenoside (4). The structures of these compounds were determined by FAB-MS, IR, 1D and 2D-NMR spectroscopy and by comparing with the published data of the closely related compounds. The antioxidant potential of the isolated iridoids (1-4) was evaluated relative to conventionally used standards and these molecules exhibited good antioxidant potential. Moreover, their inhibitory potential was also screened against three enzymes, namely acetyl cholinesterase, butyrylcholinesterase and lipoxygenase. These iridoid glucosides were found to be inactive against acetyl and butyrylcholinesterases but active against lipoxygenase.

Cotinus coggyria: a rich source of antioxidants.

Methanolic extract of Cotinus coggyria Scop. was mixed in distilled water and partitioned first with the n-hexane, then with chloroform, then ethyl acetate and at the end with n-butanol. The phytochemical screening of plant showed presence of the phenolics, cardiac glycosides and flavonoides in large amount in the chloroform, n-butanol and ethyl acetate soluble fraction. Antioxidant activity of these four fractions and the left behind aqueous fraction was measured by four methods such as: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, ferric thiocyanate assay, ferric reducing antioxidant power (FRAP) assay and total antioxidant activity. Total phenolics were also measured. Noteworthy antioxidant potential was shown by the chloroform, n-butanol and ethyl acetate soluble fraction showed. Ethyl acetate fraction showed highest % inhibition of the DPPH radical when compared with the other studied fractions i.e. 81.64 ± 1.29% inhibition of the DPPH radical at the concentration of 30 µg/ml. Its IC(50) value was found to be 15.58 ± 0.09 µg/ml, comparative to the butylated hydroxytoluene (BHT), which has IC(50) value 12.6 ± 0.85µg/ml. This fraction also showed the highest lipid peroxidation inhibition (61.41 ± 1.16%), as well as highest values of FRAP (697.76 ± 1.98 µg of trolox equivalents) total antioxidant activity (1.02 ± 0.09) and total phenolic contents (229.34 ± 0.57) comparative to the other studied fractions. The chloroform and n-butanol soluble fraction also showed good results for all the studied antioxidant assays.

In vitro assessment of relief to oxidative stress by different fractions of Boerhavia procumbens.

Methanolic extract of Boerhavia procumbens Bank ex Roxb. was partitioned with n-hexane, chloroform, ethyl acetate and n-butanol sequentially after dissolving in distilled water. Phytochemical screening showed presence of phenolics, flavonoides and cardiac glycosides in large amount in chloroform, ethyl acetate and n-butanol soluble fraction. The antioxidant activity of all these fractions and the remaining aqueous fraction was evaluated by four methods such as: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, ferric reducing antioxidant power (FRAP) assay, total antioxidant activity and ferric thiocyanate assay. Total phenolics were also determined. Some fractions showed noteworthy antioxidant activity. The results of the antioxidant activity revealed that the ethyl acetate soluble fraction showed the highest value of percent inhibition of DPPH (82.54 ± 0.62) at the concentration of 125 µ g/ml. The IC(50) of this fraction was 37.11± 0.23 µg/ml, compared with butylated hydroxytoluene (BHT), which have IC(50) of 12.1 ± 0.92 µ/mL. It also showed the highest FRAP value (251.08 ± 1.46 µg of trolox equivalents) as well as the highest value of lipid peroxidation inhibition (57.21 ± 52%), the highest total antioxidant activity (0.549 ± 0.08) and also the highest total phenolic contents (77.1 ± 0.6) as compared to the studied fractions. Phytochemical screening showed high percentage of phenolics, flavonoides and cardiac glycosides in this fraction.

6-Hydroxy-methyl-4-meth-oxy-2H-pyran-2-one (Opuntiol).

The title compound, C(7)H(8)O(4), isolated from Opuntia dillenii Haw (Cacta-ceae), is almost planar [maximum deviation of 0.027 (2) Å] except for the H atoms of the methylene and methyl groups. The crystal packing is stabilized by C-H⋯O and O-H⋯O inter-molecular hydrogen bonds, resulting in the formation of a three-dimensional network.