Cornulaca monacantha (CM) a desert plant has been utilized as adsorbent material for the removal of Hg (II) ions from contaminated water after treatment with acrylamide in alkaline medium to form carbamoylethylated Co...Cornulaca monacantha (CM) a desert plant has been utilized as adsorbent material for the removal of Hg (II) ions from contaminated water after treatment with acrylamide in alkaline medium to form carbamoylethylated Cornulaca monacantha (CECM). Three levels of CECM having different nitrogen content were prepared. The CECM samples were characterized by estimating the nitrogen content. The ability of CECM to adsorb Hg (II) was investigated by using batch adsorption procedure. The data of the adsorption isotherm was tested by the Langmuir, Freundlich and Temkin models. The removal of Hg (II) onto CECM particles could be well described by the pseudo-second order model. The adsorption rate of mercury was affected by the initial Hg (II) ion concentration, initial pH, adsorbent concentration and agitation time as well as extent of modification. The adsorption experiments indicated that the CECM particles have great potential for the removal of Hg (II) from contaminated water. The maximum adsorption capacity, Qmax of the CECM towards Hg (II) ions was found to be 384.6 mg/g at 30?C. Similarly, the Freundlich constant, n was found to be 2.03 at 30°C.展开更多
Influence of Hg(II) and Pb(II) ions on C-Phycocyanin (C-PC) from cyanobacteria Spirulina platensis was investigated using Fluorescence spectroscopy. Fluorescence measurements demonstrate quenching of C-PC emission by ...Influence of Hg(II) and Pb(II) ions on C-Phycocyanin (C-PC) from cyanobacteria Spirulina platensis was investigated using Fluorescence spectroscopy. Fluorescence measurements demonstrate quenching of C-PC emission by Hg(II) and Pb(II), and blue shifts in the fluorescence spectra. The effect of DNA on the fluorescence of Hg(II)-and Pb(II)-C-PC (from Spirulina platensis) complexes was also studied. It was shown that the fluorescence intensity of Hg-C-PC after addition of DNA gave rise to the fluorescence buildup. At the same time, addition of DNA to the Pb(II)-C-PC complexes showed no such effect. In the case of Hg(II)-C-PC, fluorescence intensity significantly decreases in time, while for Pb(II)-C-PC, decrease of the fluorescence intensity is not significant, but blue shift of the peak takes place.展开更多
The present work deals with the equilibrium adsorption of Hg(II) onto carbonized Rosmarinus officinalis leaves (ACROL) as a new adsorbent from aqueous solution and it has been investigated. ACROL samples were prepared...The present work deals with the equilibrium adsorption of Hg(II) onto carbonized Rosmarinus officinalis leaves (ACROL) as a new adsorbent from aqueous solution and it has been investigated. ACROL samples were prepared by physical carbonization at 773 K for 1 h. Titration method was used to determine the concentration of Hg(II) before and after adsorption onto ACROL by ethylenediaminetetraacetic acid, EDTA, as chelating agent. Batch equilibrium studies were carried out under different experimental conditions such as Hg(II) concentration and temperature. The relationship between the amount of Hg(II) onto ACROL can be described using four tow-parameter isotherm models. The equilibrium sorption data were analyzed using Freundlich, Langmuir, Dubinin-Radushkevich (DRK) and Temkin isotherms. The experimental results were found to fit the Langmuir isotherm model with a monolayer adsorption capacity of 588.2 mg/g at 318 K, while they were found to fit the Freundlich isotherm model at 298 K. The KL was decreased with increasing temperature, indicating a bond strength between Hg(II) and ACROL decreased with increasing temperature and sorption is exothermic. From DRK isotherm, free energy, E, was higher than 31 kJ/mol suggesting the Hg(II) adsorption onto ACROL chemical sorption. The thermodynamic studies revealed that the process is spontaneous nature of Hg(II) adsorption by ACROL and exothermic. The findings from this research show that ACROL has capability to remove Hg(II) from aqueous solutions.展开更多
Porous cellulose beads modified by histidine (PCBH) were prepared. The adsorption capacity of PCBH for divalent Mg(II), Cu(II), Pb(II) and Hg(II) ions were determined. The effects of the temperature, the initial pH va...Porous cellulose beads modified by histidine (PCBH) were prepared. The adsorption capacity of PCBH for divalent Mg(II), Cu(II), Pb(II) and Hg(II) ions were determined. The effects of the temperature, the initial pH value, the concentration of metal ion and PCBH ligand on the adsorption of Cu(II) Hg (II) were discussed. The adsorption process fitted to Freundlich adsorption isotherms for both metal ions. Adsorption rate constants were also found.展开更多
文摘Cornulaca monacantha (CM) a desert plant has been utilized as adsorbent material for the removal of Hg (II) ions from contaminated water after treatment with acrylamide in alkaline medium to form carbamoylethylated Cornulaca monacantha (CECM). Three levels of CECM having different nitrogen content were prepared. The CECM samples were characterized by estimating the nitrogen content. The ability of CECM to adsorb Hg (II) was investigated by using batch adsorption procedure. The data of the adsorption isotherm was tested by the Langmuir, Freundlich and Temkin models. The removal of Hg (II) onto CECM particles could be well described by the pseudo-second order model. The adsorption rate of mercury was affected by the initial Hg (II) ion concentration, initial pH, adsorbent concentration and agitation time as well as extent of modification. The adsorption experiments indicated that the CECM particles have great potential for the removal of Hg (II) from contaminated water. The maximum adsorption capacity, Qmax of the CECM towards Hg (II) ions was found to be 384.6 mg/g at 30?C. Similarly, the Freundlich constant, n was found to be 2.03 at 30°C.
文摘Influence of Hg(II) and Pb(II) ions on C-Phycocyanin (C-PC) from cyanobacteria Spirulina platensis was investigated using Fluorescence spectroscopy. Fluorescence measurements demonstrate quenching of C-PC emission by Hg(II) and Pb(II), and blue shifts in the fluorescence spectra. The effect of DNA on the fluorescence of Hg(II)-and Pb(II)-C-PC (from Spirulina platensis) complexes was also studied. It was shown that the fluorescence intensity of Hg-C-PC after addition of DNA gave rise to the fluorescence buildup. At the same time, addition of DNA to the Pb(II)-C-PC complexes showed no such effect. In the case of Hg(II)-C-PC, fluorescence intensity significantly decreases in time, while for Pb(II)-C-PC, decrease of the fluorescence intensity is not significant, but blue shift of the peak takes place.
文摘The present work deals with the equilibrium adsorption of Hg(II) onto carbonized Rosmarinus officinalis leaves (ACROL) as a new adsorbent from aqueous solution and it has been investigated. ACROL samples were prepared by physical carbonization at 773 K for 1 h. Titration method was used to determine the concentration of Hg(II) before and after adsorption onto ACROL by ethylenediaminetetraacetic acid, EDTA, as chelating agent. Batch equilibrium studies were carried out under different experimental conditions such as Hg(II) concentration and temperature. The relationship between the amount of Hg(II) onto ACROL can be described using four tow-parameter isotherm models. The equilibrium sorption data were analyzed using Freundlich, Langmuir, Dubinin-Radushkevich (DRK) and Temkin isotherms. The experimental results were found to fit the Langmuir isotherm model with a monolayer adsorption capacity of 588.2 mg/g at 318 K, while they were found to fit the Freundlich isotherm model at 298 K. The KL was decreased with increasing temperature, indicating a bond strength between Hg(II) and ACROL decreased with increasing temperature and sorption is exothermic. From DRK isotherm, free energy, E, was higher than 31 kJ/mol suggesting the Hg(II) adsorption onto ACROL chemical sorption. The thermodynamic studies revealed that the process is spontaneous nature of Hg(II) adsorption by ACROL and exothermic. The findings from this research show that ACROL has capability to remove Hg(II) from aqueous solutions.
文摘Porous cellulose beads modified by histidine (PCBH) were prepared. The adsorption capacity of PCBH for divalent Mg(II), Cu(II), Pb(II) and Hg(II) ions were determined. The effects of the temperature, the initial pH value, the concentration of metal ion and PCBH ligand on the adsorption of Cu(II) Hg (II) were discussed. The adsorption process fitted to Freundlich adsorption isotherms for both metal ions. Adsorption rate constants were also found.
