Browsing by Author "Premachandra, B.A.J.K."

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Catalytically induced pyrolysis of LDPE to liquid fuel
(Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Wickramaarachchi, W.A.A.S.; Premachandra, B.A.J.K.; De Silva, D.S.M.
Plastics are used in a wide range of applications because of their durability, lightweight, easy fabrication, and desired chemical and physical properties. Usually, plastic products are discarded after use to the environment as solid waste. Therefore, the low degradability of plastics and the high demand for plastic products have created a serious environmental issue. Recycling is one of the methods used in plastic waste management. As a recycling method, energy recycling or producing fuel oil from plastic waste has gained a promising interest. In this study, it was expected to convert selected used plastics to fuel oils through a pyrolysis process using a catalyst. A laboratory-scale pyrolysis system was developed and a low-cost conversation process for plastics to fuel oil was investigated in an environmentally friendly manner. Initially, virgin low-density polyethylene (LDPE) was used in this conversion as the control sample. Then waste wrapping materials made of LDPE were subjected to pyrolysis. A two-neck round bottom flask was used as the reactor while the heat was supplied by a LP gas burner. To control overheating and possible heat losses, the reactor was dipped in a soil bath during heating. A constant heating rate and a constant inert gas flow rate to the reactor were maintained throughout the experiment. The gases evolved by the pyrolysis were condensed. The distillate was collected while the uncondensed fraction was trapped first in a non-polar organic solvent and further in a basic aqueous solution to prevent possible hazardous emissions. A locally abundant mineral was tested as a possible catalyst for the pyrolysis to improve the quality of the resulting products. It was observed that the purity of the resulting fuel oil had been improved with the use of the catalyst. The resultant liquid fraction was conveyed for factional distillation and the fractions were characterized with GC-MS and FTIR techniques. According to the GC-MS analysis, the major constituents in the fraction obtained from virgin LDPE through uncatalyzed pyrolysis were decane, undecane and 1-tetradecene. The major constituents obtained through the catalytic pyrolysis of virgin LDPE were cyclopropane, 1- decene, undecane and pentadecane. The pyrolysis of waste LDPE resulted in cyclopentane, decane, undecane and 1-pentadecene as fractional distillates. The mineral tested as the catalyst has given significant improvement in the purity of the oil fractions produced. The combustion characteristics and viscosities of the resultant oils are to be determined and those will be compared with the commercially available fuel oils. The study will be extended for other plastic waste types including mixed waste.
Development of a Solvent System for Effective Leaching of Extractable Proteins in Dipped Product Surfaces
(4th International Conference on Advances in Computing and Technology (ICACT ‒ 2019), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka, 2019) Kulathilaka, C.U.N.; Jayasuriya, C.K.; Premachandra, B.A.J.K.
Allergic conditions caused by natural rubber latex (NRL) proteins have become a vast problem in the natural rubber latex industry. Leaching is one of the protein removal methods which have been used in the industry. The objective of this study was developing a leaching solvent system to remove surface NRL proteins from dipped product surfaces using urea and sodium dodecyl sulphate (SDS). In this research NRL samples were prepared and leached using 4 different solvent systems namely distilled water, urea, SDS and a mixture of urea and SDS. At a time, one sample set (3 latex sheets to triplicate the results) was leached in previously mentioned solvent systems for a particular time and then washed with flowing water. Nine sample sets were used for the study. One sample set was kept without leaching. After leaching, Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) was used for qualitative determination of remaining surface protein content and modified Lowry method was used for quantitative determination of surface proteins. Antigenic proteins on sample surfaces were quantified using enzyme linked immunosorbent assay (ELISA) which is determined by reactions between specific NRL antibodies and NRL antigenic proteins. Without leaching, the average remaining extractable protein content was above the detection limit (> 200 µg/g). Therefore, water leached sample set was used as the control. When the urea concentration in leaching was increased, the removal efficiency of surface proteins was higher when a mixture of urea and SDS was used compared to when urea alone was used. This was observed in all the concentrations of urea: SDS ratios used. The maximum removal efficiency (74.36%) was observed for the leaching solvent mixture containing urea: SDS ratio 3:1. This could be due to the fact that both urea and SDS influence in deproteination and that increases the solubility of extractable proteins. In addition, ELISA suggested that after leaching, the antigenic protein content was below the detection limit for all the solvent systems used. However, since the removal of extractable protein content was maximized when mixture of urea and SDS was used it is expected that the antigenic protein content might also be further reduced compared to other solvents used.
Finding an efficient solution system for leaching extractable proteins from natural rubber gloves
(Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Dikella, D.G.W.N.; Jayasuriya, C.K.; Premachandra, B.A.J.K.
Natural rubber latex (NRL) is used to manufacture a large number of useful products such as gloves. Allergy to NRL gloves is caused by latex proteins extractable into sweat. Extractable proteins (EP) come in contact with the skin causing allergic reactions. The protein allergy caused by latex products has become an acute problem to human health. Certain proteins or peptides eluting from NRL products can cause immediate hypersensitivity reactions (Type I allergy) in people sensitized to those proteins. The amount of total EPs in NRL gloves was assumed to reflect their corresponding amount of allergenic proteins. The major objective of this research was to develop an economical method to reduce EPs in finished NRL gloves. The current study was focused on developing a leaching solution system to remove the extractable NRL proteins from the gloves using CaCl2 solution and sodium dodecyl sulphate (SDS) solution. Rubber films were leached with varying aqueous CaCl2 (5%, 10%, 15%, w/v%) concentrations followed by leaching with SDS (5%, w/v%). After leaching, the water extractable proteins were analyzed by the analytical methodology based on the modified Lowry method according to ASTM D5712. Distilled water leached samples were used as the reference. When CaCl2 concentration in leaching was increased, the removal efficiency of EPs was increased. When the samples were leached with CaCl2 followed by SDS, they illustrated a further reduction of EPs. Thus, the amount of remaining EPs in the product decreased considerably. A maximum removal efficiency could be seen when the rubber films were leached with CaCl2 (15%, w/v%) followed by SDS (5 %, w/v%). The effect of leaching solvents on the final product was analyzed by measuring the mechanical properties such as tensile strength, tear strength and aging resistance. Distilled water leached samples were used as the reference. The mechanical properties did not change to a greater extent when rubber films were leached with CaCl2 followed by SDS when compared to that of water leached samples. Therefore, leaching rubber gloves with CaCl2 (15%, w/v%) followed by SDS (5%, w/v%) may be an efficient method for reducing EP content of the final product and thus reducing the allergenic conditions of sensitized people for NRL gloves.