Use of an activated carbon from antibiotic waste for the removal of Hg(II) from aqueous solution

Porous carbon has been prepared from waste antibiotic material by a chemical activation method using K(2)CO(3) as an activating reagent. Carbon was studied systematically by the adsorption of nitrogen and iodine. It was found that the process parameters such as activation temperature and activation time are crucial for preparing high-quality activated carbon. The proper choice of the preparation conditions allows to produce microporous activated carbon with a micropore volume up to 0.492 cm(3)/g and a BET surface area of 1260 m(2)/g. Adsorption of mercury(II) from an aqueous solution on antibiotic carbon was investigated under the varying conditions of agitation time, metal ion concentration and pH. The adsorption capacity of the carbon is 129 mg/g.     

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

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 m³/h m²), 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.     

Competitive effects and interactions during sorption of SMP fractions on activated carbon: response surface approach for visualization of sorption profiles

The objectives of this study were to investigate the significance of the effects and interactions for during competitive sorption of soluble microbial products (SMP). Batch experiments were conducted to assess the competitive sorption characteristics and individual affinity of glucose (carbohydrate) and bovine serum albumin (BSA) (protein) as two representative fractions of SMP. The influence of surface availability was investigated by using carbon particles with different particle sizes (5-75 μm, 75-850 μm, and 850-1000 μm) and different carbon amounts. Competitive effects and interactions were evaluated for each adsorbate and surface availability. Competitive sorption mechanisms were quantified in relation to surface affinity of the SMP fractions. Sorption capacity profiles of the SMP fractions at equilibrium were developed using second-degree polynomial models for the experimental data and compared with the estimates obtained from the modified Langmuir-like model which uses single parameter sorption data to estimate competitive sorption profiles of systems with two adsorbates. Adequacy limitations of the modified Langmuir-like model for each SMP fraction were evaluated based on the significance of the synergistic and antagonistic effects between the two SMP fractions and the carbon surface availability.