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This work aims to decorate carbon nanotubes with oxygenated functional groups for effective removal of Cadmium ions from aqueous media. For that purpose Carbon nanotubes (CNT) was oxidized by nitric acid to give MCNT-HNO 3 . The CNT and MCNT-HNO 3 were characterized by SEM, TEM, FT-IR, Boehm titration, nitrogen adsorption-desorption analysis, point of zero charge and surface pH. The adsorption experiments of Cd(II) onto sorbents were studied using the batch technique and factors affecting the adsorption capacities of Cd(II) were investigated and discussed. The isotherm data were analyzed using Langmuir and Freundlich equations. The equilibrium data fitted well Langmuir isotherm for both CNT and MCNT-HNO 3 . The kinetic results were analyzed using pseudo-first order, pseudo-second order, intraparticle diffusion and the Boyd equations. The rate constants, equilibrium capacities and related correlation coefficients (R 2 ) for each kinetic model were calculated and discussed. Highest values of R 2 were obtained on applying the pseudo second-order with both carbons. Although intraparticle diffusion plays impotent role in rate-controlling step in the adsorption process of Cd(II) onto the investigated sorbents, film diffusion is also controlling this process. The thermodynamic parameters including ΔG°, ΔH° and ΔS° for the adsorption processes of Cd(II) on the carbons were calculated, and the negative value of ΔG° indicated the spontaneous nature of adsorption. The desorption studies revealed that the regeneration of MCNT-HNO 3 can be easily achieved.

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A series of novel superabsorbents Fe 3 O 4 /poly(Acrylamide-co-sodium acrylate) core shell magnetic nanogel based on crosslinked poly (sodium acrylate-co-acrylamide) are investigated for the removal of methylene blue from aqueous solutions. The superabsorbents are characterized by FTIR, HR-TEM and SEM. The adsorbents exhibited high sorption capacities toward basic dyes, viz.: 2167.802-2765.893 mg g -1 . The adsorption kinetics followed a pseudo-second order equation. Equilibrium isotherm data are analyzed according to Langmuir and Freundlich equations. The thermodynamic parameters including ΔG°, ΔH° and ΔS° for the adsorption processes of MB on the nanocomposite hydrogel were also calculated, and the negative value of ΔG° indicated the spontaneous nature of adsorption. PreparationsSuperparamagnetic Fe 3 O 4 nanoparticles were prepared by chemical co-precipitation of iron (III) and iron (II) in an alkaline solution and then treating it under hydrothermal condition. In a typical experiment, 5.2 g of FeCl 3 .6H 2 O, 2 g of FeCl 2 .4H 2 O and 0.85 ml HCl (12 mol/L) were dissolved in 25 ml of DDW (degassed with nitrogen gas before use) to prepare a stock solution. 250 ml of 1.5 mol/L NaOH solution was heated to 80°C in a beaker. The stock solution was added drop wise under nitrogen gas protection and vigorous stirring. After the reaction, the mixture was cooled to room temperature with stirring, and the resulting magnetic Fe 3 O 4 nanoparticles were separated magnetically and washed with DDW four times to remove excess NaOH and finally dispersed in 100 ml DDW to be used for nanogel preparation.Core shell poly(acrylamide-co-sodium acrylate) magnetic nanogel was prepared by solution polymerization. In a typical experiment, 1.52 g acrylamide, 1.54 g acrylic acid and 0.198 g MBA (3 mol% with respect to total monomer amount) were dissolved in 72 ml DDW in an ice cooled bath followed by addition of drops of 10 M NaOH till pH=9. The reaction system was bubbling nitrogen gas to exclude the air inside the flask for 20 minute, Then 75 ml of magnetite ferrofluid (10 mg/ml) was added under vigorous stirring. Afterwards, 3 ml aqueous Research Article

Three olive stones-derived activated carbons (ACOS) with different chemical characteristics, appropriate for the removal of iron and manganese in groundwater are prepared. The steam activated carbon is obtained from carbonized olive stones in the presence of nitrogen in the temperature range from 700 to 900°C and modified by HNO 3 and ammonium persulphate. The structure of the activated carbons was characterized by N 2 adsorption at 77 K, scan electron microscopy and FTIR. B.E.T and α-methods are used to deduce the effective surface areas. The parameters (such as initial pH, temperature, etc) affecting the adsorption capacity of ACOS toward iron and manganese cations removal from aqueous solutions are investigated using batch experiments. The study of kinetic models including pseudo first order and pseudo second-order are carried out. Langmuir adsorption isotherm is investigated. Equilibrium adsorption data fitted the Langmuir adsorption isotherm well with R 2 >0.9908. The maximum adsorption capacities of ACOS for the removal of iron and manganese cations are calculated. The results obtained revealed that the sample activated by HNO 3 has the highest adsorption capacity followed by ammonium persulphate and steam activated samples. The mechanism of adsorption is proposed.