Adsorption characteristics of Cu(II) and Pb(II) onto expanded perlite from aqueous solution

The adsorption characteristics of Cu(II) and Pb(II) onto expanded perlite (EP) from aqueous solution were investigated with respect to the changes in pH of solution, adsorbent dosage, contact time and temperature of solution. For the adsorption of both metal ions, the Langmuir isotherm model fitted to equilibrium data better than the Freundlich isotherm model. Using the Langmuir model equation, the monolayer adsorption capacity of EP was found to be 8.62 and 13.39 mg/g for Cu(II) and Pb(II) ions, respectively. Dubinin-Radushkevich (D-R) isotherm model was also applied to the equilibrium data and the mean free energies of adsorption were found as 10.82 kJ/mol for Cu(II) and 9.12 kJ/mol for Pb(II) indicating that the adsorption of both metal ions onto EP was taken place by chemical ion-exchange. Thermodynamic functions, the change of free energy (DeltaG degrees ), enthalpy (DeltaH degrees ) and entropy (DeltaS degrees ) of adsorption were also calculated for each metal ions. These parameters showed that the adsorption of Cu(II) and Pb(II) ions onto EP was feasible, spontaneous and exothermic at 20-50 degrees C. Experimental data were also evaluated in terms of kinetic characteristics of adsorption and it was found that adsorption process for both metal ions followed well pseudo-second-order kinetics.     

Equilibrium, kinetic and thermodynamic studies of adsorption of Pb(II) from aqueous solution onto Turkish kaolinite clay

The adsorption of Pb(II) onto Turkish (Bandirma region) kaolinite clay was examined in aqueous solution with respect to the pH, adsorbent dosage, contact time, and temperature. The linear Langmuir and Freundlich models were applied to describe equilibrium isotherms and both models fitted well. The monolayer adsorption capacity was found as 31.75 mg/g at pH 5 and 20 degrees C. Dubinin-Radushkevich (D-R) isotherm model was also applied to the equilibrium data. The mean free energy of adsorption (13.78 kJ/mol) indicated that the adsorption of Pb(II) onto kaolinite clay may be carried out via chemical ion-exchange mechanism. Thermodynamic parameters, free energy (deltaG degrees ), enthalpy (deltaH degrees ) and entropy (deltaS degrees ) of adsorption were also calculated. These parameters showed that the adsorption of Pb(II) onto kaolinite clay was feasible, spontaneous and exothermic process in nature. Furthermore, the Lagergren-first-order, pseudo-second-order and the intraparticle diffusion models were used to describe the kinetic data. The experimental data fitted well the pseudo-second-order kinetics.     

Clarified sludge (basic oxygen furnace sludge) – an adsorbent for removal of Pb(II) from aqueous solutions – kinetics, thermodynamics and desorption studies

The basic oxygen furnace waste generated in steel plant has been used as a low cost adsorbent for the removal of Pb(II) from aqueous solution. The effect of pH, adsorbent dosage, initial metal ion concentration, contact time and temperature on adsorption process was studied in batch experiments. Results of the equilibrium experiments showed that the solution pH was the key factor affecting the adsorption characteristics. Optimum pH for the adsorption was found to be 5 with corresponding adsorbent dosage level of 5 g/L. The equilibrium was achieved within 1 h of contact time. Kinetics data were best described by pseudo second order model. The effective particle diffusion coefficient of Pb(II) is the order of 10⁻¹⁰ m²/s. The maximum uptake was 92.5 mg/g. The adsorption data can be well fitted by Freundlich isotherm. The result of the equilibrium studies showed that the solution pH was the key factor affecting the adsorption. External mass transfer analysis was also carried out for the adsorption process. The thermodynamic studies indicated that the adsorption is spontaneous and endothermic. The sorption energy (10.1745 kJ/mol) calculated from Dubinin–Radushkevich isotherm indicated that the adsorption process is chemical in nature. Desorption studies were carried out using dilute mineral acids to elucidate the mechanism of adsorption. Application studies were carried out considering the economic viewpoint of wastewater treatment plant operations.     

Removal of Pb(II) ions from aqueous solutions by sulphuric acid-treated wheat bran

Sulphuric acid-treated wheat bran (STWB) was used as an adsorbent to remove Pb(II) ions from aqueous solution. It was observed that the adsorption yield of Pb(II) ions was found to be pH dependent. The equilibrium time for the process was determined as 2h. STWB gave the highest adsorption yield at around pH 6.0. At this pH, adsorption percentage for an initial Pb(II) ions concentration of 100mg/L was found to be 82.8 at 25 degrees C for contact time of 2h. The equilibrium data obtained at different temperatures fitted to the non-linear form of Langmuir, Freundlich and Redlich-Peterson and linear form of Langmuir and Freundlich models. Isotherm constants were calculated and compared for the models used. The maximum adsorption capacity (q(max)) which was obtained linear form of Langmuir model increased from 55.56 to 79.37mg/g with increasing temperature from 25 to 60 degrees C. Similar trend was observed for other isotherm constants related to the adsorption capacity. Linear form of Langmuir isotherm data was evaluated to determine the thermodynamic parameters for the process. Thermodynamic parameters show that adsorption process of Pb(II) ions is an endothermic and more effective process at high temperatures. The pseudo nth order kinetic model was successfully applied to the kinetic data and the order (n) of adsorption reaction was calculated at the range from 1.711 to 1.929. The values of k(ad) were found to be 5.82x10(-4) and 21.81x10(-4)(min(-1))(mg/g)(1-n) at 25 and 60 degrees C, respectively. Activation energy was determined as 29.65kJ/mol for the process. This suggest that the adsorption Pb(II) ions by STWB is chemically controlled.     

Adsorption equilibrium and kinetics of polyvinyl alcohol from aqueous solution on powdered activated carbon

In this study, powdered activated carbon (PAC) was used to remove polyvinyl alcohol (PVA) from the aqueous PVA solution. The adsorption kinetics has been studied pertaining to various initial PVA concentration and PAC dosage. The rates of adsorption were found to conform to the second-order kinetics with good correlation. Boyd plot confirmed that external mass transfer was the rate-limiting step in the sorption process. The adsorption isotherm obtained resembled with H-type of isotherm, which indicated a high affinity of the solute for the sorption sites. The Freundlich model appeared to fit the isotherm data better than the Langmuir model. The thermodynamic parameters such as Delta H degrees , Delta S degrees and Delta G degrees were evaluated from the slope and intercept of linear plot of log Kc against (1/T) x 1000. The change in entropy (DeltaS degrees ) and heat of adsorption (Delta H degrees ) of PAC was estimated as 1.45 kJ mol(-1)K(-1) and 365 kJ mol(-1), respectively. The free energy of the adsorption at all temperatures was negative indicating a spontaneous process. The maximum PVA removal of 92% was obtained at a pH of 6.3 and contact time of 30 min for an adsorbent dose of 5 g/L.     

Surface adsorption of poisonous Pb(II) ions from water using chitosan functionalised magnetic nanoparticles

In this study, chitosan functionalised magnetic nano‐particles (CMNP) was synthesised and utilised as an effective adsorbent for the removal of Pb(II) ions from aqueous solution. The experimental studies reveal that adsorbent material has finer adsorption capacity for the removal of heavy metal ions. Parameters affecting the adsorption of Pb(II) ions on CMNP, such as initial Pb(II) ion concentration, contact time, solution pH, adsorbent dosage and temperature were studied. The adsorption equilibrium study showed that present adsorption system followed a Freundlich isotherm model. The experimental kinetic studies on the adsorption of Pb(II) ions exhibited that present adsorption process best obeyed with pseudo‐first order kinetics. The maximum monolayer adsorption capacity of CMNP for the removal of Pb(II) ions was found to be 498.6 mg g⁻¹. The characterisation of present adsorbent material was done by FTIR, energy disperse X‐ray analysis and vibrating sample magnetometer studies. Thermodynamic parameters such as Gibbs free energy (ΔG °), enthalpy (ΔH °) and entropy (ΔS °) have declared that the adsorption process was feasible, exothermic and spontaneous in nature. Sticking probability reported that adsorption of Pb(II) ions on CMNP was favourable at lower temperature and sticking capacity of Pb(II) ions was very high.Inspec keywords: adsorption, lead, wastewater treatment, monolayers, Fourier transform infrared spectra, X‐ray chemical analysis, magnetometers, pHOther keywords: poisonous Pb(II) ions surface adsorption, chitosan functionalised magnetic nanoparticle, CMNP, Pb(II) ions removal, aqueous solution, finer adsorption capacity, heavy metal ion removal, contact time, solution pH, adsorbent dosage, adsorption equilibrium, Freundlich isotherm model, pseudofirst order kinetics, monolayer adsorption capacity, FTIR, energy disperse X‐ray analysis, vibrating sample magnetometer study, thermodynamic parameter, sticking probability, Pb(II) ions sticking capacity, initial Pb(II) ion concentration     

Adsorption thermodynamics of stearic acid onto bentonite

Adsorption equilibrium of stearic acid onto natural bentonite with Turkish origin was studied at the temperatures of 298, 308 and 318 K. SEM and XRD analysis show that the bentonite used as adsorbent is composed of microcrystal and porous structure. The specific surface area was determined by BET method as 38.6 m(2)/g. The adsorption of stearic acid onto bentonite was conformed to the Langmiur and Freundlich isotherms. The equilibrium parameter, R(L) revealed that the bentonite is a good adsorbent for stearic acid. The sorption capacity of bentonite studied decreases with increasing temperature. However, it is concluded that the adsorption capacity of bentonite for the stearic acid under the same experimental conditions is in comparable level in terms of that of the rice husk ash given in literature. Thermodynamic parameters, DeltaG(ads) degrees , was calculated to be between -21.8 and -22.8 kJ mol(-1). DeltaH(ads) degrees and DeltaS(ads) degrees were found to be -9.2 kJ mol(-1) and 42.4 J mol(-1)K(-1), respectively. These parameters obtained as a function of temperature indicate that the adsorption of stearic acid onto bentonite was a spontaneous and an exothermic process. An FT-IR study on the adsorbed material was used to verify the interaction of the stearic molecule with bentonite after adsorption process.     

Pyridine sorption from aqueous solution by rice husk ash (RHA) and granular activated carbon (GAC): parametric, kinetic, equilibrium and thermodynamic aspects

The present study deals with the adsorption of pyridine (Py) from synthetic aqueous solutions by rice husk ash (RHA) and commercial grade granular activated carbon (GAC) and reports on the kinetic, equilibrium and thermodynamic aspects of Py sorption. Batch sorption studies were carried out to evaluate the effect of various parameters, such as adsorbent dose (m), initial pH (pH0), contact time (t), initial concentration (C0) and temperature (T) on the removal of Py. The maximum removal of Py is found to be approximately 96% and approximately 97% at lower concentrations (<50 mg dm(-3)) and approximately 79.5% and approximately 84% at higher concentrations (600 mg dm(-3)) using 50 kg m(-3) and 30 kg m(-3) of RHA and GAC dosage, respectively, at 30+/-1 degrees C. Adsorption of Py is found to be endothermic in nature and the equilibrium data can be adequately represented by Toth and Redlich-Peterson isotherm equations. Py can be recovered from the spent adsorbents by using acidic water and 0.1 N H2SO4. The overall adsorption of Py on RHA and GAC is found to be in the order of GAC>RHA. Comparative assessment of adsorbents used by various investigators available in literature showed the effectiveness of BFA and RHA over other adsorbents. Spent RHA can simply be filtered, dried and used in the boiler furnaces/incinerators. Thus, its heating value can be recovered.     

Characterization of mesoporous rice husk ash (RHA) and adsorption kinetics of metal ions from aqueous solution onto RHA

The present study deals with the characterization of low-cost rice husk ash (RHA) for its various physico-chemical properties and adsorption characteristics of metal ions. The average particle size of RHA was 150.47mum. Proximate analysis showed the presence of high amount of ash in RHA. Bulk density and the heating value of RHA were 104.9kg/m(3) and 9.68MJ/kg, respectively. The pore size distribution results showed that the RHA was predominantly mesoporous. The BET surface area was 36.44m(2)/g. The average pore diameter by BET was 42.603A. The BJH pore area showed 80% of the pore area due to the mesopores. The polar groups present on the RHA surface imparted considerable cation exchange capacity to it. RHA was found to be an effective adsorbent for the removal of cadmium (Cd(II)), nickel (Ni(II)) and zinc (Zn(II)) metal ions from aqueous solutions. The pH(0) approximately 6.0 is found to be the optimum for the removal of individual cations from the aqueous solutions by RHA at an optimum dose of 10kg/m(3). The kinetics of adsorption showed that the metal ions adsorption on RHA is a gradual process with quasi-equilibrium being attained in 5h. The pseudo-second-order kinetics represents the equilibrium data well. The effective diffusion coefficient of the cations onto the RHA is of the order of 10(-13)m(2)/s.     

Biosorption of Pb(II) and Cd(II) from aqueous solution using green alga (Ulva lactuca) biomass

The biosorption characteristics of Pb(II) and Cd(II) ions from aqueous solution using the green alga (Ulva lactuca) biomass were investigated as a function of pH, biomass dosage, contact time, and temperature. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm of the metal ions by U. lactuca biomass. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The monolayer biosorption capacity of U. lactuca biomass for Pb(II) and Cd(II) ions was found to be 34.7mg/g and 29.2mg/g, respectively. From the D-R isotherm model, the mean free energy was calculated as 10.4kJ/mol for Pb(II) biosorption and 9.6kJ/mol for Cd(II) biosorption, indicating that the biosorption of both metal ions was taken place by chemisorption. The calculated thermodynamic parameters (DeltaG degrees , DeltaH degrees and DeltaS degrees ) showed that the biosorption of Pb(II) and Cd(II) ions onto U. lactuca biomass was feasible, spontaneous and exothermic under examined conditions. Experimental data were also tested in terms of biosorption kinetics using pseudo-first-order and pseudo-second-order kinetic models. The results showed that the biosorption processes of both metal ions followed well pseudo-second-order kinetics.     

Removal of lead from aqueous solution by hybrid precursor prepared by rice hull

Use of low-cost hybrid precursor, prepared from rice hull has been studied as a sorbent for the removal of Pb(2+) from aqueous solutions. Effect of contact time, initial concentration, pH and temperature has been studied. The effect of temperature (30, 40, 50 and 60 degrees C) on adsorption phenomena has been studied and data have been analyzed using Langmuir isotherm. The change in enthalpy (Delta H) (-14.6179 kJ/mol), free energy (Delta G) and entropy (DeltaS) has also been evaluated. The negative values of Delta G and Delta H indicate the adsorption of lead ions on the surface of hybrid precursor to be spontaneous and exothermic under the experimental condition.     

Adsorption of Pb(II) and Cd(II) metal ions from aqueous solutions by mustard husk

The adsorption of Pb(II) and Cd(II) metal ions on mustard husk has been found to be concentration, pH, contact time, adsorbent dose and temperature dependent. The adsorption parameters were determined using Langmuir and Freundlich isotherm models. The adsorption isotherm studies clearly indicated that the adsorptive behavior of Pb(II) and Cd(II) metal ions on mustard husk satisfies not only the Langmuir assumptions but also the Freundlich assumptions, i.e. multilayer formation on the surface of the adsorbent with an exponential distribution of site energy. Ion exchange and surface complexation are the major adsorption mechanisms involved.

The applicability of Lagergren kinetic model has also been investigated. Thermodynamic constant (k_ad), free energy change (ΔG), enthalpy change (ΔH) and entropy change (ΔS) were calculated for predicting the nature of adsorption. The results indicate the potential application of this method for effluent treatment in industries and also provide strong evidence to support the adsorption mechanism proposed.     

Fly ash-based geopolymer for Pb removal from aqueous solution

The aim of this work was to synthesis highly amorphous geopolymer from waste coal fly ash, to be used as an adsorbent for lead Pb(II) removal from aqueous wastewater. The effect of various parameters including geopolymer dosage, initial concentration, contact time, pH and temperature on lead adsorption were investigated. The major components of the used ash in the current study were SiO(2), Al(2)O(3) and Fe(2)O(3) representing 91.53 wt% of its mass. It was found that the synthesized geopolymer has higher removal capacity for lead ions when compared with that of raw coal fly ash. The removal efficiency increases with increasing geopolymer dosage, contact time, temperature, and the decrease of Pb(2+) initial concentration. The optimum removal efficiency was obtained at pH 5. Adsorption isotherm study indicated that Langmuir isotherm model is the best fit for the experimental data than Freundlich model. It was found also that the adsorption process is endothermic and more favorable at higher temperatures.     

Biosorption of Pb(II) ions by modified quebracho tannin resin

In this study, the effect of temperature, pH and initial metal concentration on Pb(II) biosorption on modified quebracho tannin resin (QTR) was investigated. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to investigate QTR structure and morphology. Besides, the specific BET surface area and zeta-potential of the QTR were analysed. Thermodynamic functions, the change of free energy (DeltaG degrees), enthalpy (DeltaH degrees) and entropy (DeltaS degrees) of Pb adsorption on modified tannin resin were calculated as -5.43 kJ mol(-1) (at 296+/-2K), 31.84 kJ mol(-1) and 0.127 J mmol(-1) K(-1), respectively, indicating the spontaneous, endothermic and the increased randomness nature of Pb(2+) adsorption. The kinetic data was tested using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion model. The results suggested that the pseudo-second-order model (R(2)>0.999) was the best choice among all the kinetic models to describe the adsorption behavior of Pb(II) onto QTR. Langmuir, Freundlich and Tempkin adsorption models were used to represent the equilibrium data. The best interpretation for the experimental data was given by the Langmuir isotherm and the maximum adsorption capacity (86.207 mg g(-1)) of Pb(II) was obtained at pH 5 and 296 K.     

Fixed bed column study for heavy metal removal using phosphate treated rice husk

This paper reports the results of the study on the performance of low-cost adsorbent such as raw rice husk (RRH) and phosphate treated rice husk (PRH) in removing the heavy metals such as lead, copper, zinc and manganese. The adsorbent materials adopted were found to be an efficient media for the removal of heavy metals in continuous mode using fixed bed column. The column studies were conducted with 10 mg/l of individual and combined metal solution with a flow rate of 20 ml/min with different bed depths such as 10, 20 and 30 cm. The breakthrough time was also found to increase from 1.3 to 3.5 h for Pb(II), 4.0 to 9.0 h for Cu(II), 12.5 to 25.4h for Zn(II) and 3.0 to 11.3 h for Mn(II) with increase in bed height from 10 to 30 cm for PRH. Different column design parameters like depth of exchange zone, adsorption rate, adsorption capacity, etc. were calculated. It is found that the adsorption capacity and adsorption rate constant were increased and the minimum column bed depth required was reduced when the rice husk is treated with phosphate, when compared with that of RRH.     

Removal of copper(II) and lead(II) from aqueous solution by manganese oxide coated sand I. Characterization and kinetic study

The preparation, characterization, and sorption properties for Cu(II) and Pb(II) of manganese oxide coated sand (MOCS) were investigated. A scanning electron microscope (SEM), X-ray diffraction spectrum (XRD) and BET analyses were used to observe the surface properties of the coated layer. An energy dispersive analysis of X-ray (EDAX) and X-ray photoelectron spectroscopy (XPS) were used for characterizing metal adsorption sites on the surface of MOCS. The quantity of manganese on MOCS was determined by means of acid digestion analysis. The adsorption experiments were carried out as a function of solution pH, adsorbent dose, ionic strength, contact time and temperature. Binding of Cu(II) and Pb(II) ions with MOCS was highly pH dependent with an increase in the extent of adsorption with the pH of the media investigated. After the Cu(II) and Pb(II) adsorption by MOCS, the pH in solution was decreased. Cu(II) and Pb(II) uptake were found to increase with the temperature. Further, the removal efficiency of Cu(II) and Pb(II) increased with increasing adsorbent dose and decreased with ionic strength. The pseudo-first-order kinetic model, pseudo-second-order kinetic model, intraparticle diffusion model and Elovich equation model were used to describe the kinetic data and the data constants were evaluated. The pseudo-second-order model was the best choice among all the kinetic models to describe the adsorption behavior of Cu(II) and Pb(II) onto MOCS, suggesting that the adsorption mechanism might be a chemisorption process. The activation energy of adsorption (E(a)) was determined as Cu(II) 4.98 kJ mol(-1) and Pb(II) 2.10 kJ mol(-1), respectively. The low value of E(a) shows that Cu(II) and Pb(II) adsorption process by MOCS may involve a non-activated chemical adsorption and a physical sorption.     

Studies on the removal of Pb(II) from wastewater by activated carbon developed from Tamarind wood activated with sulphuric acid

The low-cost activated carbon were prepared from Tamarind wood material by chemical activation with sulphuric acid for the adsorption of Pb(II) from dilute aqueous solution. The activated carbon developed shows substantial capacity to adsorb Pb(II) from dilute aqueous solutions. The parameters studied include physical and chemical properties of adsorbent, pH, adsorbent dose, contact time and initial concentrations. The kinetic data were best fitted to the Lagergren pseudo-first-order and pseudo-second order models. The isotherm equilibrium data were well fitted by the Langmuir and Freundlich models. The maximum removal of lead(II) was obtained 97.95% (experimental) and 134.22 mg/g (from Langmuir isotherm model) at initial concentration 40 mg/l, adsorbent dose 3g/l and pH 6.5. This high uptake showed Tamarind wood activated carbon as among the best adsorbents for Pb(II).     

Comparative study of adsorption properties of Turkish fly ashes. I. The case of nickel(II), copper(II) and zinc(II)

The objective of this study was to compare two different Turkish fly ashes (Afsin-Elbistan and Seyitomer) for their ability to remove nickel [Ni(II)], copper [Cu(II)] and zinc [Zn(II)] from an aqueous solution. The effect of contact time, pH, initial metal concentration and fly ash origin on the adsorption process at 20+/-2 degrees C were studied. Batch kinetic studies showed that an equilibrium time of 2h was required for the adsorption of Ni(II), Cu(II) and Zn(II) on both the fly ashes. The maximum metal removal was found to be dependent on solution pH (7.0-8.0 for Ni(II), 5.0-6.0 for Cu(II) and 6.0-7.0 for Zn(II)) for each type of fly ash. With an increase in the concentrations of these metals, the adsorption of Ni(II) and Zn(II) increased while the Cu(II) adsorption decreased on both the fly ashes. Adsorption densities for the metal ions were Zn(II)>Cu(II)>Ni(II) for both the fly ashes. The effectiveness of fly ash as an adsorbent improved with increasing calcium (CaO) content. Adsorption data in the range of pH values (3.0-8.0) using Ni(II) and Cu(II) concentrations of 25+/-2mg/l and Zn(II) concentration of 30+/-2mg/l in solution were correlated using the linear forms of the Langmuir and Freundlich equations. The adsorption data were better fitted to the Langmuir isotherm since the correlation coefficients for the Langmuir isotherm were higher than that for the Freundlich isotherm. The fly ash with high calcium content (Afsin-Elbistan) was found to be a metal adsorbent as effective as activated carbon and, therefore, there are good prospects for the adsorptions of these metals on fly ash with high calcium content in practical applications in Turkey.     

Adsorption of Pb(II) and Pb(II)-citric acid on sawdust activated carbon: Kinetic and equilibrium isotherm studies

The removal of Pb(II) and Pb(II)-citric acid (Pb(II)-CA) from aqueous solutions by sawdust activated carbon (SDAC) was investigated. The higher adsorptive removal of Pb(II) from aqueous solutions containing Pb(II)-CA than Pb(II) only was observed due to the presence of CA in the former system. The mechanism of adsorption process was studied by conducting pH as well as kinetic studies. Batch adsorption experiments were conducted to study the effect of adsorbent dose, initial concentration and temperature for the removal of Pb(II) from Pb(II) only and Pb(II)-CA aqueous systems. The adsorption was maximum for the initial pH in the range of 6.5-8.0 and 2.0-5.0 for Pb(II) and Pb(II)-CA, respectively. The solution pH, zero point charge (pH(zpc)) and species distribution of Pb(II) and Pb(II)-CA were found to play an important role in the adsorption of Pb(II) and Pb(II)-CA onto SDAC from water and wastewaters. SDAC exhibited very high adsorption potential for Pb(II) ions in presence of CA than when Pb(II) ions alone were present. The kinetic and equilibrium adsorption data were well modeled using pseudo-first-order kinetics and Langmuir isotherm model, respectively.     

Removal of heavy metal ions from aqueous solutions using carbon aerogel as an adsorbent

The removal of Cd(II), Pb(II), Hg(II), Cu(II), Ni(II), Mn(II) and Zn(II) by carbon aerogel has been found to be concentration, pH, contact time, adsorbent dose and temperature dependent. The adsorption parameters were determined using both Langmuir and Freundlich isotherm models. Surface complexation and ion exchange are the major removal mechanisms involved. The adsorption isotherm studies clearly indicated that the adsorptive behaviour of metal ions on carbon aerogel satisfies not only the Langmuir assumptions but also the Freundlich assumptions, i.e. multilayer formation on the surface of the adsorbent with an exponential distribution of site energy. The applicability of the Lagergren kinetic model has also been investigated. Thermodynamic constant (K(ad)), standard free energy (DeltaG(0)), enthalpy (DeltaH(0)) and entropy (DeltaS(0)) were calculated for predicting the nature of adsorption. The results indicate the potential application of this method for effluent treatment in industries and also provide strong evidence to support the adsorption mechanism proposed.