The potential of water hyacinth—Eichhornia crassipes biomass immobilized in calcium alginate for the adsorption of Ni(II) from water was studied using the Langmuir and Freundlich adsorption models. The equilibrium ad...The potential of water hyacinth—Eichhornia crassipes biomass immobilized in calcium alginate for the adsorption of Ni(II) from water was studied using the Langmuir and Freundlich adsorption models. The equilibrium adsorption data were obtained at different initial Ni(II) concentrations = 0.05-2 mg/L, temperature = 30℃?± 0.2℃, agitation rate = 150 rpm, equilibration time = 3 hr, biosorbent dose =4 g/L, and pH range = 4-7.4. Langmuir isotherms gave monolayer sorption capacities (qm) of 26.5, 44.3 and 53.0 mg/g for the removal of Ni(II) in the presence of methanol, without added organic substance, and in the presence of acetonitrile, respectively. These findings were also confirmed by the trend in the Freundlich isotherm parameter (1/n? 1). Interpretation of the sorption data in terms of the separation factor, SF, suggested that the removal of Ni(II) from water mainly occurred through a chemisorption mechanism. Desorption experiments to recover Ni(II) from the adsorbent showed that highest amounts of the metal could be removed from the adsorbent when previously adsorbed in the presence of 1-(2-Thiazolylazo)-2-naphtol (TAN) (>90%). The results from these studies indicated that E. crassipes fixed on calcium alginate beads is a viable metal enrichment media that can be used freely immersed in solution to achieve very high adsorption capacities and possible preconcentration of Ni(II) in aquatic environments.展开更多
文摘The potential of water hyacinth—Eichhornia crassipes biomass immobilized in calcium alginate for the adsorption of Ni(II) from water was studied using the Langmuir and Freundlich adsorption models. The equilibrium adsorption data were obtained at different initial Ni(II) concentrations = 0.05-2 mg/L, temperature = 30℃?± 0.2℃, agitation rate = 150 rpm, equilibration time = 3 hr, biosorbent dose =4 g/L, and pH range = 4-7.4. Langmuir isotherms gave monolayer sorption capacities (qm) of 26.5, 44.3 and 53.0 mg/g for the removal of Ni(II) in the presence of methanol, without added organic substance, and in the presence of acetonitrile, respectively. These findings were also confirmed by the trend in the Freundlich isotherm parameter (1/n? 1). Interpretation of the sorption data in terms of the separation factor, SF, suggested that the removal of Ni(II) from water mainly occurred through a chemisorption mechanism. Desorption experiments to recover Ni(II) from the adsorbent showed that highest amounts of the metal could be removed from the adsorbent when previously adsorbed in the presence of 1-(2-Thiazolylazo)-2-naphtol (TAN) (>90%). The results from these studies indicated that E. crassipes fixed on calcium alginate beads is a viable metal enrichment media that can be used freely immersed in solution to achieve very high adsorption capacities and possible preconcentration of Ni(II) in aquatic environments.
