RESUMEN
This study evaluated the potential use of brown seaweed Sargassum sp to sequester lead and copper (Pb(II) and Cu(ll)) from urban runoff based on batch as well as column experiments. The equilibrium data exhibited Langmuir isotherms. The adsorption capacity of this seaweed was found to be 196.1 mgg(-1) and 84.0 mg g(-1) for Pb(ll) and Cu(ll), respectively, which are in good agreement with those values obtained for the aqueous solution (188.6 mg g(-1) for Pb(ll) and 86.9 mg g(-1) for Cu(II)). The functional group analysis of the seaweed using FTIR demonstrated that the carboxyl functional groups are mainly responsible for biosorption. The cation exchange capacity of the biosorbent was 2.25 meq/g. This observation suggested that ion exchange mechanism is predominantly responsible for the metal ion uptake. The column study showed that the highest bed height and the lowest flow rate result in a substantial enhancement of the metals uptake with the biosorption uptake capacities being 264.3 mg Pb(ll) g(-1) and 86.0 mg Cu(ll) g(-1). In the binary system, the biosorption capacity was observed to be 208.7 mg Pb(ll) g(-1) and 61.0 mg Cu(II) g(-1). The predicted breakthrough curves by the Thomas adsorption model gave a good fit of the experimental data with r2 ranging from 0.92 to 0.99.
Asunto(s)
Cobre/metabolismo , Plomo/metabolismo , Lluvia/química , Sargassum/metabolismo , Cationes Bivalentes/metabolismo , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
Antihistaminic activity of 3 or 6 mg dimethindene maleate was compared with that of placebo and 12 mg chlorpheniramine maleate in 60 healthy volunteers in a randomized, crossover study. Activity of each drug was assessed by measuring 2 micrograms histamine-induced weal and flare areas. Compared with placebo, both doses of dimethindene and chlorpheniramine significantly (P less than 0.001) reduced weal area. Both doses of dimethindene (P less than 0.001) and chlorpheniramine (P less than 0.05) also significantly reduced flare area. Dimethindene (6 mg) brought about the maximum reduction in weal area (28.8%) and flare area (39.1%). Dimethindene (6 mg) also reduced weal area significantly (P less than 0.01) compared with chlorpheniramine and reduced flare area significantly (P less than 0.05) compared with 3 mg dimethindene. Using a 100 mm visual analogue scale for assessment of weal and flare intensities, 6 mg dimethindene again produced the maximum response. The study confirmed that the antihistamine activity of dimethindene was better than that of chlorpheniramine.