Browsing by Author "Kalpage, C.S."

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    Equilibrium Isotherm Analysis of Methylene Blue Adsorption by Natural Sri Lankan Ball Clay
    (Uva Wellassa University of Sri Lanka, 2019-02) Nawarathna, T.N.T.K.; Kalpage, C.S.
    Synthetic dyes are used in the textile industry production as raw materials. Excess and dye-containing wastewater are released to the environment without proper treatments. Consequently, textile wastewater creates environmental hazards. In Sri Lanka, textile industry cannot release their wastewater without treating upto industrial discharge limits stipulated by Central Environmental Authority. The main objective of this study was to Sri Lankan ball clay has been investigated as low cost and eco-friendly adsorbent for the removal methylene blue from aqueous solution. The powder X-ray diffraction (XRD) analysis was carried out to find the structure and the type of clay mineral present in the bulk clay sample. Batch system experiments were carried observing an effect of the adsorbent dosage, contact time and initial concentration. Equilibrium isotherm of the clay materials was studied Freundlich and Langmuir model. According to the results of the influence of adsorbent dose, the removal percentage and adsorption capacity almost became constant at the dose of 6.8 g/100 ml. Therefore, it was considered the best dosage of adsorbent. As a result of contact time, it was found that the adsorption tends to attain the equilibrium in near 270 min (4.5 h). It was considered the saturation time. The results indicated that increasing adsorption capacity with increasing concentration. The equilibrium of the ball clay was found the Freundlich isotherm model was more suitable than the Langmuir model. Since the high value of the Freundlich correction coefficient (R2 = 0.9730) than the Langmuir correction coefficient (R2 = 0.9266). A conclusion is Sri Lankan ball clay can be employed as the low-cost alternative for removing the dye from industrial wastewater.
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    Processing of a Novel Low-Cost Adsorbent by Co-granulation of Egg-Shells and Tea Waste
    (Uva Wellassa University of Sri Lanka, 2019-02) Priyadarshana, V.N.; Kalpage, C.S.
    In this work, egg shells and tea waste were used during the co-granulation process with different mass fractions for the production of low cost efficient adsorbents to remove Methylene Blue (MB) from aqueous solutions. The main aim of this research was to process novel low-cost adsorbent by co-granulation of egg shells and tea waste. Specific objectives were to optimize color removal conditions by varying different mixing ratios of tea waste and egg shell and pH, to develop adsorption isotherm and adsorption kinetic model. Seven types of co-granules were produced by mixing mass fractions of tea waste and egg shells as 1.0:0.0, 0.8:0.2, 0.6:0.4, 0.5:0.5, 0.6:0.4, 0.8:0.2, 0.0:1.0 respectively. UV/Vis spectrometer (DR6000-HACH®) was used to measure concentrations. Maximum wave length of MB was 665nm. The adsorption data were fitted to Langmuir and Freundlich isotherms and adsorption parameters were determined using Newtons least square method. Equilibrium concentration data were fitted to the Langmuir isotherm model with high R-square value than Freundlich isotherm model. Therefore, Langmuir isotherm is the best fitted model for this adsorption process. Type 1 (tea to egg shell ratio is as 1.0:0.0) granules showed the maximum adsorption capacity. For type 1 co-granules, the Langmuir constants qm and b were determined as 0.21 mg/g and 6.73 L/mg and Freundlich constants KF and (1/n) were 0.16 ((mg/g) (l/mg)0.49) and 0.26 respectively. When mass fraction of tea waste increases, density decreases and specific surface area increases. Pseudo first order kinetic model is best for some types of co-granules and second order kinetic model is best for other types. When pH of initial solution increases, adsorption capacity increases. The zero-point charge (pHzpc) for tea waste was determined around 5.0. Surface of tea waste is negatively charged at higher pH values creating electroststic attraction between negatively charged surfce and MB cationic ions.