This paper presents the biosorption of chromium onto red seaweed (Polysiphonia nigrescens). Batch mode experiments were performed to determine experimental parameters affecting sorption process such as pH, contact tim...This paper presents the biosorption of chromium onto red seaweed (Polysiphonia nigrescens). Batch mode experiments were performed to determine experimental parameters affecting sorption process such as pH, contact time, initial metal ion concentration and biomass dosage. The Cr(III) sorption was dependent on pH and adsorbent dosage. The adsorption kinetic data could be fitted with a pseudo-second-order model and the equilibrium data with a Langmuir model. The maximum sorption capacity was of 16.11 mg/g at pH 4 and 10 g/L of biomass dosage. 0.1 M H2SO4 showed good desorption efficiency (>80%). Spectroscopy analysis showed that Cr(III) sorption on seaweed was mainly through the ion-exchange mechanism. This report indicates that P. nigrescens is an effective and economical sorbent for removal of Cr(III) from wastewaters.展开更多
Orange peel (OP) and rice husk (RH) were tested as low-cost biosorbents for Cr(III) removal from aqueous solutions. Dynamics of the biosorption process indicated that intraparticle mass transfer represents the rate-li...Orange peel (OP) and rice husk (RH) were tested as low-cost biosorbents for Cr(III) removal from aqueous solutions. Dynamics of the biosorption process indicated that intraparticle mass transfer represents the rate-limiting step in the system that attained equilibrium at 120 min. While the OP sorbent material was capable of taking up 39.11 mg Cr(III)/g at the optimum pH 4.4, RH immobilized 3.20 mg Cr(III)/g at the optimum pH 3.0. The fitting of different sorption isotherms models resulted in the best fit with the Langmuir isotherm model. The mean free energy of the metal sorption process was in the range of 8-16 kJ/M. Abiotic Cr(VI) reduction was observed at various contact times and Cr-laden biomass was characterized by XPS, XAFS and EPR spectroscopy. These instrumental analyses confirmed that Cr(VI) removed from the solution was reduced and bound to the biomass as Cr(III). Results indicated that OP and RH materials are efficient biosorbents for eliminating Chromium from aqueous solutions.展开更多
文摘This paper presents the biosorption of chromium onto red seaweed (Polysiphonia nigrescens). Batch mode experiments were performed to determine experimental parameters affecting sorption process such as pH, contact time, initial metal ion concentration and biomass dosage. The Cr(III) sorption was dependent on pH and adsorbent dosage. The adsorption kinetic data could be fitted with a pseudo-second-order model and the equilibrium data with a Langmuir model. The maximum sorption capacity was of 16.11 mg/g at pH 4 and 10 g/L of biomass dosage. 0.1 M H2SO4 showed good desorption efficiency (>80%). Spectroscopy analysis showed that Cr(III) sorption on seaweed was mainly through the ion-exchange mechanism. This report indicates that P. nigrescens is an effective and economical sorbent for removal of Cr(III) from wastewaters.
文摘Orange peel (OP) and rice husk (RH) were tested as low-cost biosorbents for Cr(III) removal from aqueous solutions. Dynamics of the biosorption process indicated that intraparticle mass transfer represents the rate-limiting step in the system that attained equilibrium at 120 min. While the OP sorbent material was capable of taking up 39.11 mg Cr(III)/g at the optimum pH 4.4, RH immobilized 3.20 mg Cr(III)/g at the optimum pH 3.0. The fitting of different sorption isotherms models resulted in the best fit with the Langmuir isotherm model. The mean free energy of the metal sorption process was in the range of 8-16 kJ/M. Abiotic Cr(VI) reduction was observed at various contact times and Cr-laden biomass was characterized by XPS, XAFS and EPR spectroscopy. These instrumental analyses confirmed that Cr(VI) removed from the solution was reduced and bound to the biomass as Cr(III). Results indicated that OP and RH materials are efficient biosorbents for eliminating Chromium from aqueous solutions.
