University of Peradeniya

About: University of Peradeniya is a education organization based out in Kandy, Sri Lanka. It is known for research contribution in the topics: Population & Poison control. The organization has 5970 authors who have published 7388 publications receiving 197002 citations.

Effective adsorption of toxic brilliant green from aqueous solution using peat of Brunei Darussalam: isotherms, thermodynamics, kinetics and regeneration studies

Abstract: Peat, a natural adsorbent, has been successfully used for the removal of the hazardous water-soluble cationic dye, brilliant green (BG). Characterization of peat was carried out by determining its physical and chemical compositions such as moisture, ash, carbon%, hydrogen%, nitrogen%, and sulphur% (CHNS), crude protein and crude fat. X-ray fluorescence (XRF) was used for the determination of the percentage of elements present in peat. Functional groups present in peat were analyzed using Fourier transform infra-red (FTIR). Changes in the surface morphology of peat before and after treatment with BG were studied using Scanning Electron Microscopy (SEM). The optimization time required for establishment of an adsorption equilibrium is determined to be 2.0 h. The ambient pH of BG was used throughout the study. Adsorption isotherm models such as Langmuir, Freundlich, Halsey, Temkin, Redlich–Peterson (R–P) and Sips were simulated to fit with the experimental equilibrium data. Based on linear regression, simulated isotherm models and error analyses, the R–P isotherm fitted well for the adsorption of BG by peat. Adsorption kinetics was found to follow the pseudo second order model, with a rate constant of 0.39 g mmol−1 min−1. BG-loaded peat was successfully regenerated using 0.01 M sodium hydroxide (NaOH) solution for up to 5 consecutive cycles, while maintaining high adsorption ability of 98% even after the 5th cycle.

Unfertilized ovary: a novel explant for coconut (Cocos nucifera L.) somatic embryogenesis.

Abstract: Unfertilized ovaries isolated from immature female flowers of coconut (Cocos nucifera L.) were tested as a source of explants for callogenesis and somatic embryogenesis. The correct developmental stage of ovary explants and suitable in vitro culture conditions for consistent callus production were identified. The concentration of 2,4-dichlorophenoxyacetic acid (2,4-D) and activated charcoal was found to be critical for callogenesis. When cultured in a medium containing 100 μM 2,4-D and 0.1% activated charcoal, ovary explants gave rise to 41% callusing. Embryogenic calli were sub-cultured into somatic embryogenesis induction medium containing 5 μM abscisic acid, followed by plant regeneration medium (with 5 μM 6-benzylaminopurine). Many of the somatic embryos formed were complete with shoot and root poles and upon germination they gave rise to normal shoots. However, some abnormal developments were also observed. Flow cytometric analysis revealed that all the calli tested were diploid. Through histological studies, it was possible to study the sequence of the events that take place during somatic embryogenesis including orientation, polarization and elongation of the embryos.