Browsing by Author "Pitawala, H.M.J.C."
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Item Agar-Based Gel Polymer Electrolyte with KI and Tetrapropylammonium Iodide Salts for Dye-Sensitized Solar Cell(Uva Wellassa University of Sri Lanka, 2020) Nirodha, M.D.; Nishshanke, G.B.M.M.M.; Pitawala, H.M.J.C.; Bandara, T.M.W.J.At present, energy consumption is rising predominantly, thus low cost, renewable, and environmentally benign energy resources drag attraction extensively. Although many researches have been done on polymer electrolytes, there is a captivating direction to explore bio-polymer electrolytes in a quasi-solid state. In the present work, a novel gel polymer electrolyte was prepared by a hot press method utilizing tetrapropylammonium iodide (Pr4NI) and potassium iodide (KI) as the binary iodide salt system. Agar bio polymer was combined with the glycerol and formaldehyde solvents to obtain the quasisolid state polymer plasticizer matrix. The KI and tetrapropylammonium iodide weight ratio in the electrolyte was altered while keeping the masses of other ingredients constant to optimize the solar cell performance. Gel electrolytes displayed quite high viscosity while retaining a gel-like consistency at ambient temperature. Fourier transform infrared spectroscopy results indicate a peak heightens gradually at 750 cm-1 with increasing Pr4NI salt amount. Electrical impedance spectroscopy was used to deduce the ionic conductivity of each electrolyte. The highest ionic conductivity of 3.39 mS cm−1 is achieved by the electrolyte sample only with KI at 26 °C as the contribution for ionic conductivity from small K+ cation is higher compared to the bulky Pr4N+ cation. The uniform shape of cyclic voltammetry curves of each electrolyte during 12 consecutive cycles with 5 min time steps revealed the stability of electrolytes. A dye-sensitized solar cell was assembled by inserting the highest conducting gel polymer electrolyte having Glass/FTO/TiO2/N719-Dye/GPE/Pt/Glass configuration. The dye-sensitized solar cell fabricated with the highest conducting electrolyte displayed an efficiency of 0.36% with JSC of 1.31 mA cm−2 , VOC of 0.4 V, and fill factor of 0.68. Keywords: Biopolymer, Gel polymer electrolyte, Agar, Tetrapropylammonium iodide, Dye-sensitized solar cellItem Ceramic Waste-Based Natural Rubber Composites: An Exciting Way for Improving Mechanical Properties(Uva Wellassa University of Sri Lanka, 2018) Kondrage, Y.G.; Pitawala, H.M.J.C.; Thangavel, K.; Edirisinghe, D.; Etampawala, T.N.B.Large amounts of fired ceramic waste produced in ceramic industry do not have a proper method to reuse and dumped into landfills. These solid wastes have a major environmental and economic concern. Thus, a proper management of such solid wastes is eminent. Since fired ceramics have already been sintered, their utilization as a raw material is limited. This research is dedicated to evaluating the possibility of using such ceramic waste as a low-cost filler material in the manufacture of natural rubber based composites. Ceramic particles smaller than 125 µm were selected for the preparation of our initial composites. For the latter part of the study, particles in submicrometer length scales were used. Elemental analysis and composition of the phases of the ceramic particles were determined by x-ray fluorescence and diffraction, respectively. The average particle size was characterized by scanning electron microscope (SEM) and digital particle size analyzer. The surfaces of the sub micrometer size ceramic particles were modified using Silane69 coupling agent and Oleic acid. The surface modification was confirmed by fourier-transform infrared spectroscopy, thermogravimetric analysis and SEM coupled with energy-dispersive x-ray spectroscopy. Natural rubber based composites were prepared with different levels of ceramic filler loadings. The mechanical properties of the composites such as hardness, resilience, compression set, abrasion volume loss and tensile properties were evaluated. These properties of the composites were compared with those of the composites prepared according to the same formulation except the ceramic filler (pristine rubber sample). The composites were found to have an exciting enhancement of mechanical properties with respect to the pristine rubber sample. The mechanical property improvement is higher when the ball milled sub-micrometer size ceramic filler is used and it is even better when surface modified ceramic particles are used.Item Characterisation and Implications for Potential Environmental Applications of Montmorillonite Extracted from Clay Deposits in Murunkan, Sri Lanka(Uva Wellassa University of Sri Lanka, 2019) Piyasena, K.L.R.I.; Rathnayake, S.I.; Pitawala, H.M.J.C.Montmorillonite (MMT) is one of the most commonly used smectite clay as a low‒cost adsorbent in water purification due to its ubiquitous nature, high cation exchange capacity, surface area and porosity. Although high purity MMT deposits are absent in Sri Lanka, MMT‒rich clay can be found in arid regions such as Murunkan, Mannar. Cadmium (Cd2+) is a known human carcinogenic heavy metal deemed as a high priority water pollutant by the USEPA. This study is focused on investigating the potential environmental applications of MMT as a low‒cost adsorbent for the removal of Cd2+. MMT was extracted using clay collected from Murunkan area by both wet and dry sieve methods. Wet sieve method resulted in higher percentage (14%) of fine clay fraction (<63 µm) compared to dry sieve method (3.8%). X‒ray Diffraction and Fourier Transform Infrared Spectroscopy revealed the beneficiation of montmorillonite in <63 µm fraction and main impurities were identified as quartz and feldspar. Upon sedimentation, impurity content was minimised and montmorillonite rich portion (MMT‒Ex) in <63 µm fraction was separated. The optimum adsorbent amount for effective Cd2+ removal was investigated by varying the amount of MMT-Ex (0.5‒4 g). The adsorbent was mixed with 25 ml of Cd2+ solution (5 mg L-1, pH 7.3) and agitated for 24 hrs at room temperature. The supernatant was separated by centrifugation and analysed using Atomic Absorption Spectroscopy. MMT‒Ex resulted 98% of Cd2+ adsorption with a low adsorbent dose (0.5 g). Overall, this study describes effective methods to extract MMT from MMT‒rich clay and shows its potential application as an economic and effective adsorbent for inorganic contaminants in wastewater treatment and environmental remediation.Item Characterisation of “Dummala” Origin in Sri Lanka by XRF, XRD and FTIR(Uva Wellassa University of Sri Lanka, 2019) Subasinghe, H.C.S.; Bandara, T.G.T.A.; Christopher, W.A.P.P.; Hewathilake, H.P.T.S.; Pitawala, H.M.J.C.The term Dummala is a traditional name given to the naturally occurring substance that can be found, either at uppermost crustal levels, mostly under the freshwater swampy areas or as a dried resin like gums from the Dummala tree (Shorea oblongifolia), which is endemic to Sri Lanka. The history of Dummala is dated back to more than 2000 years, where it was used in ayurvedic medication and to make flares in exorcisms and processions. Dummala which is taken out from ground, physically appears as peat-like carbonaceous matter with agglomerated coarse-grained particles. Though, this variety of Dummala is naturally occurring material found in Sri Lanka a firm scientific analysis has not yet been conducted. Therefore, this study aims to characterise the Dummala extracted from the ground, in order to investigate the chemical composition and special properties that might be suitable for the advanced applications. Initially, natural Dummala was dried and 50 g of sample (<53 µm) was obtained by mechanical sieving. X-Ray Fluorescence (XRF) spectroscopic analysis were conducted to identify the chemical composition. Further, Dummala was characterised with X-Ray Diffraction (XRD) analysis for the phase identification and the results showed that this material is partially crystalline. XRF data together with XRD analysis confirmed that Dummala which is taken out from the ground is composed mainly with Magnesium Carbonate, Silica and Sulphur. Further, the present study suggests a carbon content analysis in order to interpret the origin of Dummala.Item Characterization of Hydroxyapatite Synthesized from Commonly Available Saccostrea cucullata (Rock Oyster) Shells in Sri Lanka: Identification of a Commercial Application of Bivalve Shells(Uva Wellassa University of Sri Lanka, 2020) Peiris, M.S.D.; Thushari, G.G.N.; Pitawala, H.M.J.C.Biological shells with simple components result in outstanding properties compared to the man-made materials. Bivalve shells can be reused as a low-cost raw material for different industrial applications. This study was focused on the characterization of Saccostrea cucullata (Rock Oyster) shells collected from the Southern coastal zone in Sri Lanka and identification the potential of synthesizing commercial products from oyster shells. Collected oyster shells from Dickwella coastal belt were subjected to prepare shell powder after sieving the crushed shells using a metal sieve with 600 micron of mesh size. Shell powder samples were sintered at 1000◦C for two hours in the muffle furnace for removal of moisture, gases, and other remnants. Raw oyster shells and prepared shell powder samples were characterized using Fourier Transform Infrared Radiation (FT-IR), X-ray Diffraction (XRD) and X-Ray Fluorescence (XRF) Spectroscopy. After analysis of shell structure, functional groups, and composition, two wet precipitation techniques were employed to synthesize Hydroxyapatite (HA): (Ca10(PO4)6(OH)2). The first method includes converting shell CaCO3 into CaO as starting material, reacting with Nitric acid, Phosphate provider & NH4OH at pH 10 and sintering. The second method consists of converting calcined shell CaCO3 into Ca(OH)2, reacting with Phosphoric acid & NH4OH at pH 10, and sintering. Based on characterization results, the oyster shell is mainly composed of CaCO3 (98%), and extracted CaCO3 powder is compatible with properties of commercial CaCO3 product. Based on XRF, the oyster shell also consists of trace elements such as Zr, MgO, SO3, SiO2, and Sr. CaO level of shell powder was 97.9 % after thermal decomposition of CaCO3 during firing. HA produced from the second method recorded characteristic peak with high intensity at 2 theta value of 31.79◦ by signifying the crystalline phase only for HA compound in XRD analysis. XRD and XRF results revealed that HA powder which was produced from the second method using Ca(OH)2 as starting material & sintering at a temperature of 900oC recorded similar composition (CaO>77%, P2O5>20%) to the commercially available HA. In conclusion, rock oyster shells act as environmentally friendly, value-added by-products to manufacture HA for medical applications with the technical possibility to replace commercial HA. Keywords: Bivalve shells, Shell characterization, Fourier transform infrared radiation, Xray diffraction, X-Ray fluorescence, Industrial applications, HydroxyapatiteItem Development of a Novel Dental Filling Material Using Hydroxyapatite Derived from Waste Oyster Shells(Uva Wellassa University of Sri Lanka, 2020) Uresha, M.T.S.; Pitawala, H.M.J.C.The present study aimed at developing a novel zinc phosphate based dental cement by adding Pentacalcium hydroxide triphosphate (hydroxyapatite) as a reinforcing filler to investigate the mechanical and elution properties of the prepared specimens. Here waste oyster shells of Crassostrea madrasensis were calcined to obtain Oxocalcium. The Calcium dihydroxide precursor for the synthesis of hydroxyapatite by wet precipitation method at room temperature was prepared by dissolving Oxocalcium in water. Synthesized hydroxyapatite was added into zinc phosphate powder in seven different ratios and specimens were fabricated. X-ray fluorescence spectroscopy results of oyster shells showed that Oxocalcium (88.5%) was the major oxide while Silicon dioxide and Iron (Ⅲ) oxide were present in trivial amounts. The stoichiometric calcium/phosphorus ratio of synthesized hydroxyapatite was close to 1.7. Both Fourier Transform Infrared spectroscopy and X-ray Diffraction results of unsintered and sintered hydroxyapatite were compatible with the results of the commercial compound. The particle size of the sintered hydroxyapatite was 1.518×10-6 m. Zinc phosphate cement with 10% hydroxyapatite was identified as the ideal percentage that showed the best mechanical and chemical properties with the highest compressive and diametral tensile strengths which were 66.85×106 Nm-2 are 18.88 Nm-2 respectively. Further, it showed the lowest elution percentage in pH 3 and 5 aqueous 2-Hydroxypropanoic acid and water. Hence hydroxyapatite synthesized from waste can be used as reinforcing filler in zinc phosphate dental cement. Keywords: Zinc phospate dental cement, Hydroxyapatite, Crassostrea madrasensis, oystersItem Development of a Simple Non-toxic Scale-up Method for Extracting Crude Collagen from Yellowfin Tuna (Thunnus albacares) Skin(Uva Wellassa University of Sri Lanka, 2020) Jayasundara, J.M.S.S.; Wimalarathne, W.; Pitawala, H.M.J.C.; Ekanayake, R.M.T.C.B.; Abeyrathne, E.D.N.S.During processing, a greater quantity of fish is dumped as waste which causes a major environmental impact. Therefore, it is crucial to investigate possible ways to minimize the waste and use of these wastes at the industrial level. Thus, the current study was aimed to develop a simple, non-toxic, and scale-up method to extract crude collagen from yellowfin tuna (Thunnus albacares) skin. Collagen extraction was carried out through a pre-treatment process where the skin was agitated with 0.1 N NaOH for 48 hours. Two different acid types, lactic acid (0.4 M, 0.5 M, 0.6 M) and acetic acid (0.5 M, as in the previous study) were compared. Sodium chloride (10% w/v) was used to precipitate crude collagen. Extracted collagens were lyophilized and yield was calculated. For the agitation purpose, specially prepared agitator (30 L capacity and 50 rpm) was used. Then, 10% SDS-PAGE (sodium dodecyl sulfate and polyacrylamide gel electrophoresis) analysis and FTIR (Fourier-transform infrared spectroscopy) analysis were carried out for the identification of the extracted crude collagen. The highest yield of collagen was obtained from 0.6 M lactic acid-treated fish skin compared to the rest and it was 14.46 ± 0.56 % based on the wet weight of the skin (p < 0.05). All the crude collagen extracts of different concentrations exhibited Amide A, Amide B, Amide i, Amide ii, and Amide iii which are the characteristic spectra of collagen in the FTIR spectrum. Based on the SDS-PAGE analysis it was revealed that the crude collagen extracts have two α-bands and one β-band which is a characteristic of type I collagen. Thus, this study revealed the tuna skin is a good source to extract type I collagen for the commercial and industrial uses. Keywords: Fish collagen, Thunnus albacares, Lactic acid, Acetic acid, ExtractionItem Development of an Efficient Transdermal Drug Delivery System Based on a Novel Biopolymer Matrix(Uva Wellassa University of Sri Lanka, 2020) Jaliyabandara, K.M.S.P.; Premarathne, E. P.N.; Pitawala, H.M.J.C.Transdermal Drug Delivery Systems can be defined as a capacitor that can hold and can release a discrete dosage of a therapeutic drug that will deliver drugs through the skin and it has taken a higher consideration in the present due to its control drug-releasing mechanism. However, there are some major downsides in sustaining a controlled and slow release rate of the drug to the structural circulation. Hence developing a novel polymer matrix to enhance the biocompatibility, controlled and continuous drug-releasing became a key objective. Therefore, as a solution a transdermal drug delivery system has developed using a horse gram and corn starch based novel biopolymer which contains Diclofenac Sodium as a model drug. This novel biopolymer films were obtained with a different particle size of horse gram (<63 µm, <125 µm, <150 µm) and horse gram/corn starch ratio (25%, 50%, 100% w/w). Surface morphology, functional group analysis, water vapor transmission rate, transparency, folding endurance, and moisture content were used in characterizing the novel drug loaded biopolymer. UV–visible spectroscopy was used to analyse the releasing kinetics of the drug loaded polymer. 8.97 x 10-3 g m-2 h - 1 value of WVTR rate was observed for composition 1(100 %<63 µm Horse gram). Percentage moisture absorbance was maximum in composition 3(25 % <63 µm Horse gram) (25.78%) and percentage moisture loss was maximum composition 2(50 % <63 µm Horse gram) (18.82%). A dialysis tube test with a pH 7.44 buffer solution indicated that the bio polymer matrix with particle size is less than 63µm and contains 100% horse gram shows significantly higher releasing kinetics than the other formulations. Diclofenac Sodium release models from the polymer matrix demonstrate two diffusions, approaching a first order and Fickian controlled-diffusion model for 8 h. Hence this new biodegradable polymer matrix shows significant potential as a delivery platform in the cosmetics and pharmaceutical industries. Keywords: Controlled release, Drug delivery, Release kinetics, Biopolymer, Diclofenac sodiumItem Development of Novel Bricks Using Ceramic Waste(Uva Wellassa University of Sri Lanka, 2016) Alahakoon, A.A.D.D.C.B.; Ranasinghe, S.; Pitawala, H.M.J.C.The major ceramic waste found in the ceramic industry is called filter cake. This is a semi¬solid material and mainly generated during the processes of tile glazing and shaping. It is estimated that 15 to 30% waste is produced from the total raw materials used. However, there are no popular methods to reuse this waste. Therefore we study and develop novel bricks using above ceramic waste. Different types of proto type brick samples were fabricated using pure filter cake and also mixing shaping waste, kiln roller waste, rice husk, red clay and cement into the filter cake. The mechanical properties of the samples were carried out using Universal Tensile Machine (UTM). The density, water absorption and pH of different samples were also obtained during this study. The results showed that red clay incorporated samples have high mechanical properties and very low water absorption compared to pure filter cake, pure red clay, and other investigated mixtures. However, the density of red clay incorporated filter cake mixture is higher compared to pure filter cake. The chemical composition of the filter cake and red clay was obtained using XRF analysis in order to determine the major elements present in these two materials. Our analysis showed that filter cake consists of SiO, (55.83%), A1,03 (17.41%), and CaO (7.72%) whereas red clay consists of SiO, (60.67%), A1,03 (15.18%), and Fe20, (7.61%) as major compounds. These values clearly indicate both filter cake and red clay have quit similar chemical compositions and can be obtained as homogenous mixtures. Therefore, addition of red clay into ceramic waste and develop novel bricks would be a very good solution compared to using ceramic waste alone, to reuse the ceramic waste in Sri Lankan ceramic industry. Also, high abundance of red clay in Sri Lanka will lower the production cost. Keywords: Ceramic waste, Filter cake, Red clay, Mechanical properties, XRF analysisItem Development of Poly Urethane based Composite using Plastic Waste of PET Bottles and Agro Waste(Uva Wellassa University of Sri Lanka, 2019) Kirushanthi, T.; Pitawala, H.M.J.C.; Edirisinghe, D.; Ratnaweera, D.R.; Etampawala, T.N.B.In general, more than 75% of the materials which are daily used by a human being are made out of polymers. But most of them are very hazardous to the environment and human health. If these polymers are recyclable at least waste problems can be mitigated. Most of the plastic products contain fillers in order to minimize the production cost. Silica is one of the commonly used filler which is mostly produced from the sand rich with silica. The silica production involves hazardous chemicals too. We found that silica can be effectively extracted from the rice husk ash using precipitation method. This silica may be used as a filler to improve the mechanical properties of the polymer. Also, we are mainly focusing to give a solution to waste management of Poly Ethylene Terephthalate (PET) based plastics and rice husk. Specifically, in this work we degrade PET waste using glycolysis method to get hydroxyl terminated-PET (h-PET) molecules that can be used as a precursor to make polyurethanes (PUs) with commercially available diisocyanates. Further, the synthesized PU is reinforced by introducing silica extracted from rice husk ash. Series of PU samples were made from varying the wt% ratio of hydroxyl terminatedPET molecules and methylene diphenyl diisocyanate (MDI). Formulated PUs were characterized using Fourier transform infrared spectroscopy (FT-IR). The optimum ratio of MDI to h-PET was found to be 1:1 which was confirmed by the results of FT-IR. Extracted silica was characterized using FT-IR, X- ray diffractometry, X-ray fluorescence spectrometry and scanning electron microscopy. Different wt% of extracted silica was incorporated to the synthesized PU. Interestingly, we found that the free diisocyanate of MDI form new chemical bonds with silanol groups present in extracted silica which was confirmed from FT-IR analysis. Thus, the enhanced mechanical properties in the composite were accounted due to the formation of well mixed silica particles in the PU matrix.Item Development of Polylactic Acid Incorporated Hydroxyapatite Composite for Bio-medical Applications(Uva Wellassa University of Sri Lanka, 2019) Ekanayake, E.M.D.K.; Pitawala, H.M.J.C.; Wijesekara, K.B.Hydroxyapatite (HA) is one of the extensively used materials for bone replacements and tooth fillings because of its chemical and structural similarity to the main mineral component of human bone and teeth. However, poor mechanical properties such as load bearing ability limits the applications of pure hydroxyapatite. Developing new composite materials incorporating polymer into porous pure hydroxyapatite could significantly improve the mechanical properties of HA enabling it to be used in more load bearing applications. Polylactic acid (PLA) is a widely used biopolymer in biomedical engineering due to its excellent biocompatibility and biodegradability. In this study, we have developed a polymer-HA composite by incorporating PLA into hydroxyapatite matrix derived from Sri Lankan rock phosphate. This was done at room temperature. PLA was dissolved in dichloromethane and mixed with hydroxyapatite by constant stirring. Then the mixtures were left for drying at room temperature for 24 hrs. The developed material was then characterized by Fourier Transform Infrared (FTIR) spectroscopy, XRay diffraction (XRD) and Differential Scanning Calorimetry (DSC). FTIR results indicated that PLA has successfully incorporated into the HA matrix to form a stable composite. XRD spectra confirmed that the PLA-HA composite has a crystalline structure. DSC analysis showed that the developed PLA-HA composite has a higher thermal stability. The composite developed in this study has the potential of using in various biomedical applications and would bring more economic value to Sri Lankan rock phosphate.Item Effect of Boomi Tree (Litsea glutinosa) Wax on Internal Quality and Sensory Attributes of Chicken Eggs Stored Under Room Temperature(Uva Wellassa University of Sri Lanka, 2021) Rathnayake, H.M.N.C.; Pitawala, H.M.J.C.; Abeyrathne, E.D.N.S.Shell eggs having a short shelf life at room temperature. Surface coatings can be used to extend the shelf life and minimize economic losses. Edible mineral oil is used as a coating material but several drawbacks are associated. Waxes are most commonly used hydrophobic film forming materials. Boomi tree (Litsea glutinosa) is found throughout Sri Lanka and its bark mucilage consists of hetero-polysaccharide used in ayurvedic medicine. However, information on boomi tree wax coating on egg quality attributes does not exit. Hence, this study was done to check the effect of boomi tree wax as an external coating material on shelf life, internal quality and sensory attributes of chicken eggs stored under room temperature. Total of 270 freshly laid brown, medium sized, clean eggs were purchased from a layer farm in Demodara. Eggs were individually weighed and coated with boomi wax and mineral oil separately while non-coated eggs were used as the negative control and kept in room temperature. Weight loss, air sac volume, Haugh unit, yolk color, albumen and yolk pH, yolk index, FTIR analysis, Salmonella test and sensory attributes were weekly determined. Albumen and yolk pH were increased. But the increment in the mineral oil coated was significantly lower than the other two (p<0.05). Haugh unit (75.0 to 53.6) and yolk index (0.44 to 0.22) decreased during storage in wax coated and non-coated eggs (p<0.05). Grades of non-coated and boomi wax coated, eggs changed from AA to B within 04 weeks whereas those of mineral oil coated eggs remained in AA. Weight loss of wax coated eggs were significantly higher compared to mineral oil coated eggs (p<0.05). Salmonella sp. were detected in several weeks during storage conditions showing permeability of the microorganisms. FTIR analysis revealed that no chemical changes occurred due to the wax. Increase of air sac was higher in noncoated eggs (5.39±0.3mm) after 42 days compared to wax (4.59±0.2mm) and mineral oil (1.19±0.3mm) coated eggs. In 3 week of storage sensory data was showed significant in sensory parameters. In conclusion, this study showed that Boomi wax is not a suitable coating material for chicken eggs. Keywords: Boomi tree wax; Chicken egg; Haugh unit; Yolk index; Mineral oilItem Effect of Solvent Type and Extraction Time on Yield and Purity of Lotus (Nelumbo nucifera)Leaf Wax(Uva Wellassa University of Sri Lanka, 2018) Prasadika, H.K.A.E.; Liyanage, N.P.P.; Pitawala, H.M.J.C.; Senevirathna, J.D.M.This study was conducted with the main objective of extracting lotus leaf wax using a simple methodology and to analyze the wax yield and purity of the extracted wax corresponding to different time treatments. Past studies have found that lotus plant leaf wax contains a mixture of aliphatic compounds mainly nonacosanol and nonacosanediols. Fresh, cleaned lotus leaves with 1 cm2 in surface area were exposed to three organic solvents (methanol, acetone and chloroform) and time taken for the presence of light green colour (due to the extraction of chlorophyll) in the medium was recorded to find out the most efficient organic solvent. Further, contact angle measurements of water drops placed on each of the leaf samples treated with different solvents were calculated to find out the efficiency of wax extraction. Based on the results obtained from this study leaf samples with surface area of 72.41 cm2 were exposed to chloroform by changing the dipping time duration ranging from two seconds to 30 minutes with time intervals of two seconds for the first five treatments ,15 seconds for the next three and five minutes for the last seven treatments. Extracted wax was subjected to the FTIR analysis to find out the purity of the wax. According to the results it was revealed that green colour was appeared in methanol within the first five minutes and there was no color change in the chloroform and acetone for about 30 minutes. Moreover, least change of the contact angle was shown by the leaf sample which was treated with acetone and it reveals that wax extraction was not done in an efficient manner. Chloroform is the best solvent to extract lotus leaf wax among three organic solvents used. The highest mean yield gives out by the time treatment with the dipping time of 20 minutes. And it shows that the purity decreases with the increase of the dipping time duration. KeywordsItem Effect of TiO2 nano-filler on ionic conductivity of poly (ethylene oxide) based gel polymer electrolyte for magnesium ion batteries(Uva Wellassa University of Sri Lanka, 2015) Jayarathna, R.A.; Pitawala, H.M.J.C.; Dissanayake, M.A.K.L.Gel polymer electrolytes (GPEs) have been identified as novel materials for magnesium ion rechargeable batteries. Among different polymers, poly(ethylene oxide) (PEO) based systems are the most studied candidates due to their solvation power, complexion ability, and proper (Dissanayake et al., 2012). However, ionic conductivity of PEO based polymer electrolytes at ambient temperature is not high enough for most practical applications. In order to improve the ionic conductivity, the addition of nano sized oxide fillers into the PEO-salt matrix have been regarded as the most promising method (Agrawal et al., 2013). We here present the synthesis and characterization of PEO based Mg ion conducting GPE by incorporating titanium dioxide nano filler (TiO 2). Methodology PEO (Mw~1×10 ), magnesium triflate (MgTf) (purity˃97%), ethylene carbonate (EC) (purity ˃99%), propylene carbonate (PC) (purity ˃99%) were purchased from sigma Aldrich and used as starting materials along with titanium dioxide (TiO2) nano-filler. Prior to use, polymer, salt and TiO2 were vacuum dried using appropriate temperatures. Nano composite polymer electrolytes were prepared by adding different amounts of TiO2 (2,5,7.5,10,15 wt.%) in the PEO:MgTf :EC/PC (1:1) mixture with weights of 0.20 g, 0.12 g, 0.30 g and 0.30 g respectivel y. The mixtures were heated to 80 C and magnetically stirred for 12 hours without heating until a homogenous gel was formed. The cathode film was prepared using vanadium pentoxide (V 2O5), carbon black and polyvinylidene fluoride (PVdF) with the weight percentages of 76%, 14% and 10% respectively with the solvent of 1-methyl -1, 2-dipyrrolidine using doctor blade method. The prepared electrolytes were characterized in order to obtain their ionic conductivity using complex impedance spectroscopy whereas electrochemical tests were performed using the cells, Mg/electrolyte/V2O5:C. DC polarization tests were done using both blocking (stainless steel) and non-blocking (Mg) electrodes. Microscopic images of the electrolytes were taken using the polarization microscope to investigate the change of crystallinity with the addition of nano-filler. Figure 01(a) shows the temperature dependence of ionic conductivity for the GPEs, PEO:MgTf:EC/PC (1:1), incorporating different wt. % of nano-sized TiO2 filler. Among studied systems, highest ionic conductivity is observed for the GPE with 5 wt. % filler content. Figure 01(b) shows the variation of conductivity with different wt. % TiO2 at various temperatures (conductivity isotherms) for the PEO:MgTf:EC /PC (1:1) GPEs. This plot also shows that the 5 wt.% filler containing electrolyte has the highest ionic conductivity in the studied temperature range. A possible explanation to this effect could be the availability of extra hopping sites for migrating ionic species due to formation of Lewis acid-base type interactions of ionic species with O/OH surface groups on TiO2 nano filler (Pitawala et al., 2008).Item The Effectiveness of the Particle Sizes of Rice Husk Powder and Clearing Nut Seed Powder for Removal Efficiency of Cd (II) from Wastewater(Uva Wellassa University of Sri Lanka, 2020) Tharshigah, K.; Henagamage, A.P.; Pitawala, H.M.J.C.Biomaterials are considered as efficient removers of heavy metals from wastewater through biosorption. The main goal of this study was to investigate the effect of particle sizes of Rice Husk Powder (RHP) and Clearing Nut Seed (Strychnos potatorum) Powder (CNSP) for the removal efficiency of Cd (II) in synthetic wastewater. Rice husks collected from the Badulla area were thermally treated at 200°C for 3 hours and clearing nut seeds collected from the same area were dried at room temperature for 7 days and powdered. Batch experiments were conducted to study the effect of particle sizes of biomaterials (0.5-1.0 mm, 150-500 µm, <63 µm) and contact time (2, 4, 6 hours) in removal efficiency by keeping other factors at constant (Adsorbent dosage = 1.5 g, pH = 5, Cd(II) initial concentration = 100 ppm, Cd(II) volume = 50 ml, Temperature = 25±2°C, Agitation speed = 150 rpm). The characterization of the materials before and after treating with Cd (II) was analyzed using SEM, FT-IR, XRD, and XRF. The characterization analysis revealed that both are fibrous in nature and rich in SiO2. The results of the study showed a linear positive strong correlation between removal efficiency and reducing particle size for both materials (p < 0.05). The lowest particle size (<63 µm) of RHP and CNSP showed higher removal efficiency except for the mixture of materials and they were 84.12% & 78.74% respectively. The highest removal efficiency (85.12%) was obtained for 1:1 mixture of the materials with the particle size <63 µm at the contact time of 4 hours. The reduction of FT-IR peak intensity for Si-O after the treatment confirms the participation of functional groups in metal binding. SEM images confirmed the changes in surface morphology of materials after the treatment. In conclusion, a decrease in particle size causes an elevation in removal efficiency of Cd (II) due to the presence of large surface area for biosorption and 1:1 mixture of RHP and CNSP is an efficient biomaterial for Cd (II) removal. Keywords: Rice husk powder, Clearing nut seed powder, Particle size, Cadmium, Removal efficiencyItem Effects of Hik Tree (Lannea coromandelica) Wax on Internal and Sensory Attributes of Chicken Eggs Stored Under Room Temperature(Uva Wellassa University of Sri Lanka, 2019) Pushpakumara, P.M.U.; Pitawala, H.M.J.C.; Abeyrathne, E.D.N.S.To increase the shelf life and to preserve the nutrient content under room temperature mineral oil used as an external coating material for eggs. But it is very expensive and dry slowly than other coating materials. Hik tree (Lannea coromandelica) is a tropical tree grown in dry zone in Sri Lanka and its wax has film forming properties. However, information on Hik tree wax coating on egg quality attributes does not exist. Therefore, this study was done to check the effect of Hik tree wax as an external coating material on shelf life, internal quality and sensory attributes of chicken eggs during storage under room temperature. Total of 306 white, medium sized, clean eggs were purchased from a commercial layer farm in Mahiyanganaya. Eggs were individually weighed and arranged under completely randomized design to 03 different coating treatments as Hik wax (HW), mineral oil (MO), and non-coated (NC) and stored under room temperature (27±2°C) for 6 weeks. Weight losses, Haugh unit (HU), albumen and yolk pH, air sack volume and microbial analysis for Salmonella sp. were determined weekly with 03 replicates. Sensory attributes of eggs were measured using 30 untrained panelists. FTIR analysis was conducted to analyze the structural changes in egg albumen. Results revealed that weight losses were minimum in MO coated eggs than in other treatments (p<0.05). HU decreased from 88.00 to 57.34 significantly in NC eggs compared with HW or MO (p<0.05). Albumen and yolk pH values increased during the storage in all treatments (p>0.05) and air sack volume increased from 0.41 cm to 0.71 cm during storage (p>0.05). However, grade of coated eggs reduced from AA to B within 04 weeks. All coated eggs were negative for Salmonella test during the study period. Color of the egg yolk did not change due to coating material (p>0.05). FTIR data confirmed that no chemical changes occurred due to wax coating. In conclusion, the present study confirmed that Hik tree wax can be used as an external coating material replacing MO.Item Evaluation of Physiochemical Changes in Raw Chicken Eggs Stored at Room Temperature(Uva Wellassa University of Sri Lanka, 2018) Pathirana, H.H.R.; Aruppala, A.L.Y.H.; Pitawala, H.M.J.C.; Abeyrathne, E.D.N.S.Chicken eggs are widely used in the world, due to perishability which undergoes deterioration with the time. This affects with egg processing industry and to economic losses. In this study, physiochemical changes of raw chicken eggs (RCE) stored at room temperature (28-31 °C) were determined. A total of 60 medium sized white shelled RCE obtained from 61-wk old Hyline White hens were analyzed for weight loss (%), yolk color, Haugh unit, USDA grade, pH of egg yolk and egg white and Fourier transform infrared (FTIR) spectrums at 0, 1, 4, 8, 12, 16, 20, 24, and 29 days Microbial analysis for Salmonella was checked at 0 and 29 days of storage. Weight loss (%) and pH of egg white and yolk increased whereas Haugh unit and USDA grade decreased at 29th day. Yolk color significantly increased (p < 0.05) from 12 to 14 and weight loss (%) increased (p < 0.05) from 0 to 6.27 with the storage time. However, Haugh unit showed a significant decrease (p < 0.05) from 85.13 to 40.33 and USDA grade significantly decreased (p < 0.05) from AA grade to B grade during 29 days of storage. Albumin pH and yolk pH significantly increased (p < 0.05) from 8.81 to 9.59 and from 5.77 to 6.43, respectively. Salmonella was not observed in RCE during storage at room temperature. FTIR spectrums indicated changes occurred in bonds of Amide A (3304 cm-1), Amide I (1637 cin-1), Amide II (1547 cm'), Amide III (1238 cm'), Amide IV (594 cm l), Asymmetric CH3 Stretching (2925 cm') and Symmetric CH2 Stretching (3304 cm-1). Moreover, secondary structural changes were detected in protein in RCE during the storage. In conclusion, RCE showed significant physiochemical changes in weight loss, Haugh unit, albumin pH, yolk pH and chemical structures during the storage period upto 29 days at room temperature. KeywordsItem Fabrication & Characterization of a Novel Soap Material Based on the selected Value- Added Sri Lankan Clay Minerals with Extracted Saponin from Dry Fruit of Sapindus emerginata(Uva Wellassa University of Sri Lanka, 2021) Delpechithra, N.T.; Premarathne, E.P.N.; Pitawala, H.M.J.C.Soap referred to as stain removal material as a result of a saponification reaction between lye solution and fat/oil. In some soap industries clay minerals are used as a filler material which facilitate the structure and riser attribute of soap. Instead of that these clay minerals have the ability to remove stain and exfoliate the dead skin and act as a moisturizer. There are many clay types that can be found locally which are related to kaolin. However, those clay types do not showcase some qualities such as anti-bacterial effect, anti-fungal effect, moisturizing effect, foaming effect related to skin care. Therefore, those natural clay types have not been used previously for cosmetic purposes. Under this investigation, a non-ionic natural bio surfactant called saponin which was extracted from the dry fruit of Sapindus emerginata (soapnut) was used to improve above mentioned lacking qualities. Saponin makes skin soft and acts as moisturizing agent, gentle foaming agent, natural exfoliant, and very good anti- fungal and anti-bacterial agent. Four clays were used for this investigation. Except montmorillonite clay, other three were obtained from different areas of Sri Lanka i.e; kaolin clay from Meetiyagoda, kirimati from Kandy, Makulu clay from Wadduwa. From each clay type, three samples were prepared by varying the clay amount as 2g (6.7 wt%), 4g (13.3 wt%) and 6g (20 wt%) by maintaining the temperature of the solution as 30 °C in order to find out the best clay species for soap production. Each of the sample were tested for the TFM value, total alkalinity content, moisture content, foam height and pH value. These values were compared with the international standards of soaps. Almost all the parameters of prepared soap samples were within the standard ranges. As per the results, Meetiyagoda clay and Makulu clay were the best clays for soap production and the best composition is 20 wt% which contain 6g of clay. Keywords: Kaolin; Sapindus emerginata; saponin, montmorillonite; SaponificationItem Integrated Wastewater Treatment Using Water Hyacinth (Eichhornia crassipes) and Blue Swimming Crab (Portunus pelagicus) Shell Waste(Uva Wellassa University of Sri Lanka, 2018) Samarasinghe, U.S.; Thushari, G.G.N.; Abegunawardana, A.P.; Liyanage, N.P.P.; Pitawala, H.M.J.C.Natural compounds and biotic structures are used as low cost, eco-friendly methods to treat industrial wastewater by phytoremediation and adsorption/biosorption. Objective of this study was to assess applicability of readily available blue swimming crab (P. pelagicus) shell waste and water hyacinth (E. crassipes) for removing of heavy metals, organic and inorganic pollutants from wastewater. Integrated waste water systems (IWWS) with 10 different treatments of crab shell powder + water hyacinth (Shell powder as dry weight + water hyacinth as wet weight basis: 2 g & 100 g/ 2 g & 200 g/4 g & 100 g/4 g & 200 g/6 g & 100 g/6 g & 200 g/8 g & 100 g/8 g & 200 g/10 g & 100 g/10 g & 200 g) were subjected to analyse efficiency of each treatment. Efficacy of improved rate of Dissolved oxygen, removal capacity of COD, pH, TS, TDS and P03-4 was tested in each treatment for 6-day retention period. Removal capacity of Cr, Cd and Cu levels was assessed in each treatment for 4-day contact period. According to results, both blue swimming crab shell powder levels and water hyacinth weight significantly affect on water quality improvement (p < 0.05). pH in all treated systems improved at 7.0, indicating optimum levels. The 4 g of crab shell powder with 200 g of water hyacinth recorded highest DO (4.1 ± 0.16), while removal rate of COD (95% ), TS (72%), TDS (61%) and PO3-4 (65 - 55% for 1 - 3ppm of PO3-4 levels) were most effective at same treatment. Integrated system with 4 g crab shell +200 g water hyacinth had 92 - 78%, 86 - 77% and 96 - 86% of maximum removal efficiency for Cr, Cu and Cd respectively indicating suitability of crab shell and water hyacinth for IWWS. Metal adsorption capacity depends on adsorbent dosage, pH level, metal ion charge, initial heavy metal concentration, and ionic radius of metal. This study implies novel approach in wastewater treatment as a cost effective, environmentally acceptable method, while controlling freshwater invasive alien species load and value addition to crab shell residues.Item Ionic Liquid Based Gel Polymer Electrolyte for Magnesium Ion Batteries(Uva Wellassa University of Sri Lanka, 2016) Rathnayake, R.R.D.V.; Dissanayake, M.A.K.L.; Pitawala, H.M.J.C.We present here the synthesis and characterization of ionic liquid incorporated poly (ethylene oxide) (PEO) based Mg2+ ion conducting gel polymer electrolyte for magnesium- ion rechargeable batteries. In this work magnesium triflate Mg(TO,was used as the salt in order to facilitate the Mg2+ ion conduction and N-butyl-N¬methylpyrrolidinium bis(triflouromethylsulfonAimide (PyR14TFSI) ionic liquid was used as an additive to increase the transport properties of the electrolyte. The Complex impedance spectroscopy was used in order to measure the ionic conductivity whereas D.C. polarization test was used in order to obtain the transference numbers of the electrolyte. The polymer-ion and ionic liquid-ion interactions were investigated using FT¬IR spectroscopy. Our results shows that the maximum ionic conductivity (1.021x10-4 Sem¬' at room temperature) can be obtained with the electrolyte having PEO: Mg(TO, is 15:1 molar ratio. The addition of ionic liquid into the parent electrolyte shows the further improvement in ionic conductivity with the highest value of 3.204x 10-4 Scmi for the 20wt.% ionic liquid. The electronic transference number of the electrolyte without ionic liquid is 0.129 and the electrolyte with l Owt.% of ionic liquid is 0.024. Our FTIR results show minor changes of the interactions of PEO and Me when addition of ionic liquid. Thus, this structural modification after addition of ionic liquid has a major influence for the transport properties of the parent polymer electrolyte. Keywords: Gel polymer electrolyte, Ionic liquid, Poly (ethylene oxide),Magnesium Triflate