This study deals with eco-compatible solutions for the reuse of the waste material of leaves that accumulate on the beach due to both human activities and to storms at sea. The use of dried and re-hydrated biomass of marine macrophytes was investigated as an alternative and low-cost biomaterial for removal of arsenic (V), vanadium(III) and molybdenum(V) from wastewaters. Full factorial experiments were realized for arsenic, where the main factors were the macrophyte species (brown algae: Cystoseira, Dictyopteris, Eisenia; green algae: Caulerpa, Ulva; red algae: Ceramium, Gracilaria, Porphyra; seagrass: Zostera), equilibrium pH (in the range 1 to 8), under relatively high (10 mg/L) and relatively low (100 ?g/L) arsenic concentration. For vanadium and molybdenum, the combined effects on biosorption performance by Posidonia oceanica waste biomass of equilibrium pH and metal concentrations were investigated in an ideal single-metal system and in more real-life multicomponent systems. There were either with one metal (vanadium or molybdenum) or with the two metals (vanadium and molybdenum). All species exhibited arsenic significant adsorption: red, green, brown algae and seagrasses. Indeed, they showed a good performance, with the highest observed value of about 1.3 ± 0.1 mg/g for the red algae Ceramium and the seagrass Zostera, comparable with those of activated carbon and other low-cost adsorbents reported in the literature under similar experimental conditions. Moreover, red algae known in the literature to be bad cationic metal sorbents, showed very good arsenic sorption performance. For the single-metal solutions containing either vanadium or molybdenum, the optimum was at pH 3, where a significant proportion of vanadium was removed (ca. 70%) while there was about 40% adsorption of molybdenum. The data obtained from the more real-life multicomponent systems showed that biosorption of one metal was improved both by the presence of the other metal, suggesting a synergistic effect on biosorption rather than competition. Overall, the results suggest that such waste biomass can be used as an efficient biosorbent for removal of arsenic, vanadium(III) and molybdenum(V) from aqueous solutions.
Recycling of waste biomass of marine macrophytes as arsenis, vanadium, molybdenum biosorbents
Stefano UBALDINI;
2013
Abstract
This study deals with eco-compatible solutions for the reuse of the waste material of leaves that accumulate on the beach due to both human activities and to storms at sea. The use of dried and re-hydrated biomass of marine macrophytes was investigated as an alternative and low-cost biomaterial for removal of arsenic (V), vanadium(III) and molybdenum(V) from wastewaters. Full factorial experiments were realized for arsenic, where the main factors were the macrophyte species (brown algae: Cystoseira, Dictyopteris, Eisenia; green algae: Caulerpa, Ulva; red algae: Ceramium, Gracilaria, Porphyra; seagrass: Zostera), equilibrium pH (in the range 1 to 8), under relatively high (10 mg/L) and relatively low (100 ?g/L) arsenic concentration. For vanadium and molybdenum, the combined effects on biosorption performance by Posidonia oceanica waste biomass of equilibrium pH and metal concentrations were investigated in an ideal single-metal system and in more real-life multicomponent systems. There were either with one metal (vanadium or molybdenum) or with the two metals (vanadium and molybdenum). All species exhibited arsenic significant adsorption: red, green, brown algae and seagrasses. Indeed, they showed a good performance, with the highest observed value of about 1.3 ± 0.1 mg/g for the red algae Ceramium and the seagrass Zostera, comparable with those of activated carbon and other low-cost adsorbents reported in the literature under similar experimental conditions. Moreover, red algae known in the literature to be bad cationic metal sorbents, showed very good arsenic sorption performance. For the single-metal solutions containing either vanadium or molybdenum, the optimum was at pH 3, where a significant proportion of vanadium was removed (ca. 70%) while there was about 40% adsorption of molybdenum. The data obtained from the more real-life multicomponent systems showed that biosorption of one metal was improved both by the presence of the other metal, suggesting a synergistic effect on biosorption rather than competition. Overall, the results suggest that such waste biomass can be used as an efficient biosorbent for removal of arsenic, vanadium(III) and molybdenum(V) from aqueous solutions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
