Removal of Pb(Ⅱ) ions from aqueous solution using activated tea waste:Adsorption on a fixed-bed column

摘要

An inexpensive and effective adsorbent was developed from waste tea leaves for the dynamic uptake of Pb(Ⅱ). Characterization of the adsorbents showed a clear change between physico-chemical properties of activated tea waste and simply tea waste. The purpose of this work was to evaluate the potential of activated tea waste in continuous flow removal of Pb(Ⅱ) ions from synthetic aqueous effluents. The performance of the system was evaluated to assess the effect of various process variables, viz., of bed height, hydraulic loading rate and initial feed concentration on breakthrough time and adsorption capacity. The shape of the breakthrough curves was determined for the adsorption of Pb(Ⅱ) by varying different operating parameters like hydraulic loading rate (2.3-9.17 m~3/h m~2), bed height (0.3-0.5 m) and feed concentration (2-10 mg/l). An attempt has also been made to model the data generated from column studies using the empirical relationship based on the Bohart-Adams model. There was an acceptable degree of agreement between the data for breakthrough time calculated from the Bohart-Adams model and the present experimental study with average absolute deviation of less than 5.0%. The activated tea waste in this study showed very good promise as compared with the other adsorbents available in the literature. The adsorbent could be suitable for repeated use (for more than four cycles) without noticeable loss of capacity.