Browsing by Author "Jayasundara, U. K."

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Comparison study of the oxalate content in commonly used green leafy vegetables
(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Liyanage, J. V.; Jayasundara, U. K.
Consumption of large amount of oxalate could be harmful because of the formation of calcium oxalate deposits in vital tissues or organs of the body. Patients with kidney stone problems are advised to limit dietary oxalate intake to 40-50 mg per day. In this study, commonly consumed green leafy vegetables (GLVs) such as spinach, Gotukola, cup leaves, Mukunuwanna, leeks, Kangkung, Hathawariya, Minchi, Kathurumurunga, Thebu, curry leaves, Bulath, manioc, cabbage and salad leaves were studied gravimetrically to determine the oxalate content. Edible portion of plant material was air dried, homogenized, refluxed for 12 hours, filtered, extracted with analytical grade diethyl ether, saturated with a calcium solution and then separated. The diluted and acidified solution with distilled water was titrated with standard KMnO4 assuming oxalate was the only oxidizable species. The experiments were carried out in triplicate for each species. Only a very few related studies are available in literature and the results were comparable. The results revealed that oxalate contents in GLVs ranged from (556.04 ± 1.60) mg to (3.20 ± 2.45) mg per 20 g of raw GLV portion. Also, the results confirmed that the GLVs can be divided into four categories based on the oxalate content as high (> 200 mg), medium (199 mg – 100 mg), low (99 – 10 mg) and undetectable (< 10 mg). Hathawariya, spinach, curry leaves and Kankung showed the highest amount of oxalate ranging from 556.04 ± 1.60 to 238.04 ± 1.84 mg per 20 g, while cabbage, salad leaves and leeks showed undetectable amount of oxalate ranging from 7.47 ± 1.84 to 3.20 ± 2.45 mg. It is interesting to note that commonly consumed GLVs by Sri Lankans have detectable amount of oxalate content which exceeds the minimum advisable level according to American Diabetes Association. Adding such GLVs to meal along with calcium supplements may worsen the health condition of kidney stone patients.
Safety culture and safety compliance in some chemical laboratories in Sri Lanka.
(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Nishadya, S. M. S.; Samaranayake, A. D. A. I.; Jayasundara, U. K.
Chemical laboratories are dangerous work places if proper safety practices are not implemented. There have been a number of incidents, including fatalities, reported from chemical laboratories in Sri Lanka and worldwide due to lack of safety compliance and poor safety culture which are integral parts of occupational health and safety. Therefore, the goal of this study was to examine the safety culture and the level of safety compliance that exists in chemical laboratories in Sri Lanka. A survey was administered through the industrial placement and scientific training course participants to their supervisors in 2019 in which some questions were adapted from the 2012 international safety culture study. None of the participants were below 20 years of age and majority were in the age range of 31-40 years. The results demonstrated a potential gap between how safety is managed at the participating institutions. For instance, more than 89% of participants state that they have received their safety training from respective supervisors which could be suspicious as all the supervisors were not safety officers. About 7% said they do not conduct any form of risk assessment prior to their assigned work and 57 % said they always wear personal protective equipment when performing laboratory work. About 76% of the participants believe that the safety rules and regulations have positive impact on productivity and 46% believe the safety has equal importance as other lab priorities. Though 39% of the participants think that safety procedures are stringent, 33% claims the safety procedures should be more stringent. A majority believes that the safety in their laboratories could have been improved during the past years. Even though results suggest that laboratories do have proper safety measures, they still have compliance issues due to lack of a national law and positive safety culture.
Study of adsorption efficiencies of acid-modified banana pseudo stem biomass (BPSB) using methylene blue and rhodamine B as industrial dyes
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Mendis, C. V. J.; Jayasundara, U. K.
The research explores the adsorptive removal of Methylene Blue (MB) and Rhodamine B (RhB), two industrial dyes, using both dried and acid-modified BPSB. BPSB was chosen as the adsorbent cause it is very cheap to prepare, and banana trees are readily available in Sri Lanka. The investigation, conducted through batch sorption studies, varied operational variables (dye concentration, pH, contact time, temperature and adsorbent dosage) to determine the optimal conditions for maximum dye adsorption. The highest adsorption capacity for MB was observed at a pH of 7 (pH range taken as pH 3–11) and a temperature of 40 °C (temperature range taken as 20–70 oC), with an acid-modified BPSB dosage of 0.3 g (dosage rage was taken 0.1– 0.5 g). The adsorption equilibrium was reached within 2 hours at a dye concentration of 500 ppm (concentration range taken from 100–2500 ppm) (0.1 M HCl acid-modified BPSB 0.3 g used and the adsorption capacity was 487.1 mg/g; 0.1 M HNO3 acidmodified BPSB 0.3 g used and the adsorption capacity was 492.3 mg/g). In contrast, the adsorption capacity of RhB was less influenced by pH variations (pH range taken as pH 3–11), with the most efficient removal occurring at 40 °C (temperature range taken as 20–70 oC) and a similar BPSB dosage and contact time, but at a reduced dye concentration of 300 ppm (concentration range taken from 100– 500 ppm). After running three replicas and calculating the median value, obtained the most accurate results. The adsorbents were characterized using Scanning Electron Microscopy (SEM), which provided detailed imagery of the biomass's surface morphology. Unfortunately, there were no observed changes in surface morphology before and after the adsorption process. The kinetic data fits the pseudosecond-order model very well. The thermodynamic data correlated well with the Langmuir, Freundlich, and Temkin Adsorption Isotherms. The findings of this study highlight the potential of BPSB as an effective and environmentally friendly adsorbent for the treatment of dye-contaminated water. The adaptability of BPSB to various operational conditions, coupled with its low manufacturing costs, instils optimism about its economic feasibility and positions it as a promising candidate for large-scale applications in water purification. BPSB is a natural substance and environmentally friendly. This leads to a green method for water purification. This research adds to the broader conversation on sustainable environmental management by promoting the use of agricultural waste to address water pollution. This finding showcases the innovative progress in water treatment and the continuous endeavours to protect our planet's most crucial resource.