Browsing by Author "Abesekara, MS"

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    item: Conference-Extended-Abstract
    Adsorption and desorption studies of heavy metals on to coconut shell char
    (Department of Chemical and Process Engineering, University of Moratuwa, 2019) Abesekara, MS; Kosvinna, KNR; Amarasinghe, BMWPK; Rathnasiri, PG
    Heavy metals in wastewater can be removed by several methods including adsorption. Activated carbon (AC) is widely used, but expensive adsorbent. Since AC derived from coconut shell (CS) is a good adsorbent, coconut shell char (CSC) as well might be an effective low-cost adsorbent. It was studied the possibilities of using CSC as an adsorbent. Results showed that, CSC has 13% and 12% removal efficiencies for Zn2+ and Ni2+ from solutions of 50 mg/l. Furthermore, desorption abilities of H2SO4, NaOH, Distilled water and NaCl as desorbing agents were analysed and found H2SO4 to be the most effective desorbing agent.
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    item: Conference-Full-text
    Study on fluidization behaviour of raw and dry Sri Lankan black pepper
    (IEEE, 2020-07) Abesekara, MS; Dissanayake, DMKNL; Jayatunga, GK; Amarasinghe, BMWPK; Weeraddana, C; Edussooriya, CUS; Abeysooriya, RP
    Fluidized bed drying of Sri Lankan black pepper is commercially feasible due to short drying time and uniform heating. Knowledge on the fluidization behavior is important in dryer design and performance calculations. Despite the fact, that the theoretical minimum fluidization velocity (Umf) is a constant for a given solid-fluid system, recent studies have shown that Umf is a function of the bed weight. In this study, fluidization behavior of both raw and dry black pepper at various bed weights was studied. Both raw and dry pepper found to exhibit aggregative fluidization and belong to group D of Geldart classification of solids. An empirical mathematical correlation was developed to relate Reynolds number at minimum fluidization velocity (Remf) and the bed weight per unit bed cross section for pepper. Additionally, Burke-Plummer equation of minimum fluidization was modified, and correlation coefficients were determined. Results thus obtained show that Umf is a function of bed weight per unit cross section to the power 0.25 and 0.35 for raw and dry black pepper, respectively. Furthermore, it was observed that during drying of pepper from moisture content 465% to 13%, true density, bulk density and Umf decrease by 54%, 36% and 32%, respectively.