Kinetic and Equilibrium Modelling on Copper(II) Removal by Live and Dead Cells of Trichoderma asperellum and the Impact of Pre-Treatments on Biosorption

In this study, the approach is to evaluate the use of Trichoderma asperellum biomass as a biosorbent for Cu²⁺ removal. Both live and dead cells are investigated. The feasibility of T. asperellum as biosorbent is further explored by pre-treating the cells and evaluating their subsequent Cu²⁺ removal efficacy. Results revealed that dead cells of T. asperellum attained biosorption equilibrium within the first 10 min of contact with Cu²⁺ while live cells reached equilibrium after 20 min. Dead cells also absorbed significantly higher amounts of Cu²⁺ (12.42 mg g^?1) compared to live cells (5.69 mg g¹). The biosorption mechanism for both live and dead cells of T. asperellum complied with the Langmuir isotherm and pseudo second-order kinetic, suggesting monolayer sorption. Pre-treatment of dead cells with alkali solutions (NaOH and laundry detergent) further improved sorption efficacy.     

Sorption Studies of Uranium on Novel Imino Diacetamide Grafted Styrene Divinyl Benzene Polymeric Resin

Imino diacetamide styrene divinyl benzene (IDAA SDVB) resin was evaluated for the sorption of uranium from sulphuric acid medium. Uranium sorption on to the resin was fast, the kinetic data fitted well in pseudo second order kinetics model. Sorption of uranium was found to increase with the increase in initial concentration of uranium in aqueous feed solution, the sorption isotherm data fitted closely in to Langmuir isotherm model. The sorption of uranium is observed to decrease with the increase in initial feed acidity thereby, allowing sorption and desorption at lower (0.1 M H₂SO₄) and higher (1.0 M H₂SO₄) acidities, respectively.     

Selective Separation of Uranium using Alizarin Red S (ARS)-Modified Anion-Exchange Resin or by Flotation of U-ARS Chelate

ABSTRACT

An alizarin red S (ARS)-modified anion-exchange resin was prepared by a simple reaction of ARS with the anion exchanger Doulite A101 and used for the efficient sorption of uranium from aqueous media. The effect of various parameters on the sorption of U(VI) (pH effect, sorption kinetics, resin capacity and breakthrough curves) was investigated. The modified resin sorbs U(VI) over a wide range of pH (2·8–5) with a maximum sorption capacity of 0·68 mmol.g^?1 at pH 3·2 to 4·0. Iron (III), Zr(IV), Ti(IV), Cu(II), and Th(IV) ions are also sorbed to different extents, but Be(II), Bi(III), Ca(II), Mg(II), Pb(II), Hg(II), Zn(II), Cd(II), AI(III), Mn(II), Co(II) and Ni(II) are not sorbed; thus, conditions for separating U(VI) from these metal ions have been identified. For eluting U(VI) from the resin, 0·2 mol.L^?1 HCl was used and the recovery recorded was as high as 99.9%. The use of ARS is extended to float uranium quantitatively and selectively from aqueous media at pH = 4 by using oleic acid as a surfactant. The different parameters affecting the flotation process have also been investigated. Uranium(VI) has been effectively separated from natural water samples and certified uranium ores using both procedures.     

Sorption of cadmium and lead ions on modified groundnut (Arachis hypogea) husks

The removal of cadmium and lead ions from aqueous solutions by groundnut husks modified by reaction with EDTA (% N = 12.05) was examined by equilibrium sorption studies at 29°C. The maximum metal ion binding capacity of the EDTA-modified husk determined from the sorption isotherm from solutions of pH 6.8 was found to be 0.36 mmol g^?1 and 0.19 mmol g^?1 for Cd(II) and Pb(II) ions, respectively. It was found that the rate of sorption was particle-diffusion controlled, and the particle-diffusion control rate coefficient was determined to be of the order of 10^?2 min^?1.     

Extraction and Adsorption Behavior of Co(II) on HTTA-Impregnated Polyurethane Foam

Abstract

The batch extraction of Co(II) from aqueous solutions with open cell polyethertype HTTA-loaded polyurethane (PU) foam has been studied using a radiotracer technique. The effect of pH, shaking time, and loading capacity has been investigated. The membrane properties of loaded PU foam sorbent offer unique advantage of adsorption. The fundamental studies of adsorption show that the classical Freundlich and Langmuir isotherms are followed in the entire concentration range of a 10^?5 to 10^?2 M solution of cobalt. The sorption mean free energy from the Dubinin-Radushkevich isotherm is found to be 13.8 kJ·mol^?1 and the loading capacity 4.44 mg·g^?1, suggesting that the ion-exchange or chemisorption mechanism operates. The kinetic parameters of adsorption also support a chemisorption mechanism and the first-order rate law. The rate constants and activation energies of sorption and desorption have been evaluated. The thermodynamic function of adsorption of ΔH, ΔS, ΔG, and equilibrium constant K _c have been calculated. The process of adsorption is established to be endothermic and chemisorption, stabilized through thermodynamic functions.     

Biosorption of phenolic compounds by the brown alga Sargassum muticum

Phenol, 2‐chlorophenol (2‐CP), and 4‐chlorophenol (4‐CP) biosorption on Sargassum muticum, an invasive macroalga in Europe, has been investigated. The efficiency of this biosorbent was studied measuring the equilibrium uptake using the batch technique. A chemical pre‐treatment with CaCl₂ has been employed in this study in order to improve the stability as well as the sorption capacity of the algal biomass. The influence of pH on the equilibrium binding and the effect of the algal dose were evaluated. The experimental data at pH = 1 have been analysed using Langmuir and Freundlich isotherms. It was found that the maximum sorption capacity of chlorophenols, q_max = 251 mg g^?1 for 4‐CP and q_max = 79 mg g^?1 for 2‐CP, as well as that of a binary mixture of both chlorophenols, q_max = 108 mg g^?1, is much higher than that of phenol, q_max = 4.6 mg g^?1. Moreover, sorption kinetics have been performed and it was observed that the equilibrium was reached in less than 10 h. Kinetic data have been fitted to the first order Lagergren model, from which the rate constant and the sorption capacity were determined. Finally, biosorption of the phenolic compounds examined in the present study on Sargassum muticum biomass was observed to be correlated with the octanol‐water partitioning coefficients of the phenols. This result allows us to postulate that hydrophobic interactions are the main responsible for the sorption equilibrium binding. Copyright © 2006 Society of Chemical Industry     

Biosorption of palladium and platinum by sulfate‐reducing bacteria

The biosorption capacities of palladium and platinum were studied in three different species of Desulfovibrio: Desulfovibrio desulfuricans, Desulfovibrio fructosivorans and Desulfovibrio vulgaris. The influence of several parameters such as pH, acidic background and competitor anions on biosorption equilibria and biosorption kinetics were evaluated. Differences were observed between the three strains of Desulfovibrio with respect to the optimum biosorption parameters of both metals, suggesting differences in the metal speciation–dependent sorption mechanisms involved. The most promising Pd and Pt biosorption results were obtained using D desulfuricans with rapid achievement of equilibrium (90% of total sorption was achieved in 5–15 min) and a maximum value of 190 mg g^?1 dry biomass and 90 mg g^?1 dry biomass for Pd and Pt accumulation respectively, at pH 3. Copyright © 2003 Society of Chemical Industry     

Removal of lead (II) and cadmium (II) from aqueous solutions using spent Agaricus bisporus

The sorption of Pb and Cd from aqueous solutions by spent Agaricus bisporus was investigated. The effects of contact time, pH, ionic medium, initial metal concentration, other metal ions presence and ligands were studied in batch experiments at 25°C. Maximum sorption for both metals was found to occur at an initial pH of around 5.5. The equilibrium process was well described by the Langmuir isotherm model, with maximum sorption capacities of 0.2345 and 0.1273 mmol g^?1 for Pb and Cd respectively. Kinetic data followed the pseudo‐second‐order kinetic model. The presence of NaCl and NaClO₄ caused a reduction in Cd sorption, while Pb sorption was not remarkably affected. The presence of other metals did not affect Pb removal, while the Cd removal was much reduced. HCl or EDTA solutions were able to desorb Cd from the spent Agaricus bisporus (SAB) completely, while an approximately 60% and 15% desorption yield was obtained for Pb when HCl 0.01 mol L^?1 or EDTA 0.001 mol L^?1 were used, respectively. The results of FTIR, SEM and EDX analysis indicated that other mechanisms, such as surface complexation and electrostatic interactions, must be involved in the metal sorption in addition to ion exchange. © 2012 Canadian Society for Chemical Engineering     

Biosorption of methylene blue from aqueous solution by softstem bulrush (Scirpus tabernaemontani Gmel.)

BACKGROUND: The removal of methylene blue from aqueous solution was studied using softstem bulrush (Scirpus tabernaemontani Gmel.) as the biosorbent. The effects of various parameters including contact time, biosorbent dosage, ionic strength and solution pH on the biosorption were investigated. RESULTS: The sorption capacity increased with an increase in biosorbent dosage and a decrease in ionic strength. The equilibrium time was found to be 240 min for full equilibration. Pseudo‐first‐order, pseudo‐second‐order, Bangham equation and intraparticle diffusion models were applied to fit the kinetic data, and the results showed that the sorption process followed the pseudo‐second‐order model. Equilibrium data conformed to Langmuir and Redlich–Peterson isotherm models, with a maximum monolayer biosorption capacity of 53.8 mg g^?1 for the Langmuir isotherm at 18 °C. The value of ΔG was estimated to be ? 29.24 kJ mol^?1, indicating the spontaneous nature of the biosorption. The biosorption process was strongly pH‐dependent and favourable at alkaline pH. CONCLUSION: Softstem bulrush, which is readily available and inexpensive, could be employed as a promising biosorbent for the removal of dye. Copyright © 2008 Society of Chemical Industry     

Adsorptive removal of anionic and non‐ionic surfactants from aqueous phase using Posidonia oceanica (L.) marine biomass

BACKGROUND: In this study, the capability of low‐cost, renewable and abundant marine biomass Posidonia oceanica (L.) for adsorptive removal of anionic and non‐ionic surfactants from aqueous solutions have been carried out in batch mode. Several experimental key parameters were investigated including exposure time, pH, temperature and initial surfactant concentration. RESULTS: It was found that the highest surfactant adsorption capacities reached at 30 °C were determined as 2.77 mg g^?1 for anionic NaDBS and as 1.81 mg g^?1 for non‐ionic TX‐100, both at pH 2. The biosorption process was revealed as a thermo‐dependent phenomenon. Equilibrium data were well described by the Langmuir isotherm model, suggesting therefore a homogeneous sorption surface with active sites of similar affinities. The thermodynamic constants of the adsorption process (i.e. ΔG°, ΔH° and ΔS°) were respectively evaluated as ? 8.28 kJ mol^?1, 48.07 kJ mol^?1 and ? 42.38 J mol^?1 K^?1 for NaDBS and ? 9.67 kJ mol^?1, 95.13 kJ mol^?1 and ? 174.09 J mol^?1 K^?1 for TX‐100. CONCLUSION: Based on this research, valorization of highly available Posidonia oceanica biomass, as biological adsorbent to remove anionic and non‐ionic surfactants, seems to be a promising technique, since the sorption systems studied were found to be favourable, endothermic and spontaneous. Copyright © 2007 Society of Chemical Industry     

Biosorption of thorium from aqueous solution by Ca-pretreated brown algae Cystoseira indica

The potential use of a biosorbent, Cystoseira indica, obtained from the Persian Gulf was investigated for the removal of Th (IV) ions from aqueous solutions by considering equilibrium, kinetic and thermodynamic aspects. The FT-IR spectra of unloaded and Th-loaded biomass indicated various functionalities on the biomass surface including hydroxyl, amide and carboxyl groups, which are responsible for the binding of thorium ions. Th (IV) uptake by C. indica was pH dependent. An increase in biosorbent dosage up to 1 g/L caused an increase in the Th (IV) percentage removal. Biosorption process at all studied initial Th (IV) ion concentrations follows the pseudo-second order kinetic model. The biosorption data could be well described by Redlich-Peterson isotherm in comparison to Langmuir and Freundlich isotherms. The maximum sorption capacity of Th (IV) by Langmuir isotherm was estimated to be 169.49 mg/g at 45 °C with pH of 3. The thermodynamic parameters indicated the biosorption of Th on the biomass was a feasible, spontaneous and endothermic process. Th sorption capacity remained unaffected or slightly affected (<10% inhibition) in the presence of several interfering ions such as uranium (VI), nickel (II) and copper (II). The reusability of the biomass was also determined after five sorption-desorption cycles.     

Biosorption of Strontium Ions by Magnetically Modified Yeast Cells

The sorption of Sr²⁺ ions from aqueous solutions on magnetically modified fodder yeast (Kluyveromyces fragilis) cells and their subsequent desorption were studied. The Sr²⁺ sorption increased with increasing pH and reached a plateau between pH 4.0 and 7.0. The changes of temperature slightly influenced the sorption process. The sorption values were 19.5 mg g^?1 and 53.5 mg g^?1 for 10 mg L^?1 and 40 mg L^?1 Sr²⁺ solutions respectively after 20 min incubation at a pH higher than 4. The Langmuir isotherm was successfully used to fit experimental data; the maximum adsorption capacity was 140.8 mg g^?1 under optimal conditions. The adsorbed Sr²⁺ ions can be desorbed with nitric acid (0.1 mol L^?1).     

Nickel and cobalt sorption on anaerobic granular sludges: kinetic and equilibrium studies

The kinetics and equilibria of sorption of the divalent metal ions cobalt and nickel onto anaerobic granular sludge are described. Single component and binary equimolar systems were studied at different pH values (pH 6, 7 and 8). The kinetic modelling of metal sorption by anaerobic granular sludge has been carried out using Lagergren equations. On fitting the experimental kinetic data both in first‐ and pseudo‐second‐order equations, the regression analysis of a pseudo‐second‐order equation gave a higher r² value, indicating that both external mass transfer and intra‐particle diffusion are involved in the sorption process. The experimental isotherm data were analysed using the Langmuir, Freundlich and Redlich–Peterson equations. The Redlich isotherm, a combination of the Langmuir and Freundlich equations, was found to have the highest regression correlation coefficients at pH 7. At pH 8, the Langmuir mechanism dominated for cobalt and nickel adsorption. In contrast, at pH 6, the Freundlich equation gave a better correlation coefficient which suggests a more heterogeneous adsorption at that pH. The maximal adsorption capacity of the granular sludge, as determined by the Langmuir equation, for cobalt or nickel in single systems (8.92 mg g^?1 Co TSS; 9.41 mg g^?1 Ni TSS, pH 7) compared with binary systems (8.06 mg g^?1 Co TSS; 8.43 mg g^?1 Ni TSS, pH 7) showed no great difference in the accumulation of these metals onto granular sludge. Copyright © 2004 Society of Chemical Industry     

Adsorption of uranium from sulfate leach liquor using rice straw impregnated with chlorophenyl hydrazinyl pyrazoloquinazolinon

The impregnation of rice straw with 2-amino-3-(2-(4-chlorophenyl)hydrazinyl)-8,8-dimethyl-8,9-dihydropyrazolo[1,5-a]quinazolin-6(7H)-one (CPHPQ) has been used for the recovery of uranium from sulfate leach liquor. The uranium adsorption and elution of solvent impregnated mercerized rice straw (SIMRS) were carried out using a batch technique. The uranium adsorption controlling factors include pH, initial uranium concentration, contact time, S/L ratio, and temperature. Thermodynamic characteristics showed that the adsorption process is exothermic with enthalpy change ΔH = ?152.1 kJ/mol. The kinetics data fit well with a pseudo-second-order model. The equilibrium data fit well with the Langmuir isotherm. Uranium cake was obtained from the eluate solution using hydrogen peroxide as UO₄.2H₂O precipitate.     

Haematoxylin sorption onto yak hair: kinetic and thermodynamic studies

The kinetic and thermodynamic behaviours of haematoxylin sorption onto yak hair as a model system were investigated. It was found that the sorption kinetics of haematoxylin on hair followed a pseudo‐second‐order kinetic model. The equilibrium sorption capacity increased as the temperature increased from 303 to 313 K, but dropped gradually as the temperature increased beyond 313 K. The maximum equilibrium sorption capacity was 24.04 mg g^?1 at T = 313 K. Meanwhile, the sorption isotherm data were ingood agreement with the Freundlich isotherm, presenting high coefficients (R² > 0.99). The free energy change (ΔG), enthalpy change (ΔH), and entropy change (ΔS) terms for haematoxylin dyeing were also determined, the negative values of ΔG and ΔH obtained indicated that the haematoxylin dye sorption process is a spontaneous and an exothermic one. Also, positive values of ΔS showed an increase in disorder of the system of haematoxylin sorption onto hair. Haematoxylin could be a good candidate as a natural green dye for hair fibre.     

Nickel removal characteristics of an immobilized macro fungus: equilibrium,kinetic and mechanism analysis of the biosorption

BACKGROUND: An immobilized new biosorbent was prepared from macro fungi Lactarius salmonicolor for the effective removal of nickel ions from aqueous media. Operating conditions were optimized as functions of initial pH, agitation time, sorbent amount and dynamic flow rate. Immobilization and biosorption mechanism were examined and the developed biosorbent was tested for the removal of nickel ions from real wastewater. RESULTS: Biosorption performance of the biomass continuously increased in the pH range 2.0–8.0. The coverage of the biosorbent surface by silica gel resulted in a significant increase in biosorption yield of nickel ions. The highest nickel loading capacity was obtained as 114.44 mg g^?1 using a relatively small amount of immobilized biosorbent. Biosorption equilibrium time was recorded as 5 min. Experimental data were analyzed by different isotherm and kinetic models. Infrared spectroscopy, scanning electron microscopy and X‐ray energy dispersive analysis confirmed the process. The sorbent exhibited relatively good recovery potential in dynamic flow mode studies. Biosorption capacity of immobilized biosorbent was noted as 14.90 mg g^?1 in real wastewater. CONCLUSION: Silica gel immobilized biomass of L. salmonicolor is to be a low cost and potential biosorbent with high biosorption capacity for the removal of contaminating nickel from aqueous media. © 2012 Society of Chemical Industry     

Sorption studies for Cd(II) sequestration from aqueous solution on chemically modified Albizia lebbeck

In the present work, a new sorbent was successfully prepared by chemically modifying pods of Albizia lebbeck (AL) by Fenton’s reagent, followed by sodium silicate. Sorption studies were carried out by batch process. The optimum pH was found to be 6. Equilibrium isotherm data were analysed by non-linear curve fitting analysis, to fit Langmuir, Freundlich and Temkin isotherm models. Based on the Langmuir isotherm model, maximum monolayer sorption capacity (qm) was found to be 21.22 mg.g^?1 at 50°C. Breakthrough and exhaustive capacities were found to be 10 and 50 mg.g^?1, respectively. Desorption study showed 95% recovery of Cd(II) ions.     

Biosorption of heavy metals from aqueous solution using modified activated carbon: comparison of linear and nonlinear methods

BACKGROUND: Biosorption of heavy metals from aqueous solution by modified activated carbon with Phanerochaete chrysosporium immobilised in Ca‐alginate beads was investigated using a batch system and comparison of linear and nonlinear methods. RESULTS: The amount of Cu(II), Zn(II) and Pb(II) ion sorption by the beads was as follows: activated carbon with P. chrysosporium immobilised in Ca‐alginate beads (ACFCA) (193.4, 181.8, 136.6 mg g^?1) > activated carbon immobilised in Ca‐alginate beads (ACCA) (174.8, 162.0, 130.7 mg g^?1) > P. chrysosporium (F) (148.8, 125.6, 120.4 mg g^?1) > activated carbon (AC) (138.8, 112.3, 109.3 mg g^?1) > plain Ca‐alginate beads (PCA) (125.4, 105.2, 98.2 mg g^?1). The widely used Langmuir and Freundlich isotherm models were utilised to describe the biosorption equilibrium process. CONCLUSION: The results of this study suggest that the immobilisation of modified activated carbon with P. chrysosporium in Ca‐alginate beads is suitable for a batch system. The isotherm parameters were estimated using linear and nonlinear regression analyses. The surface charge density of the biosorbents varied with the pH of the medium; the maximum biosorption of heavy metal ions on the biosorbents was obtained when the pH was between 5.6 and 7.4. Copyright © 2008 Society of Chemical Industry     

Sorption of Natural Uranium on Weakly Basic Anion Exchangers

The effects of the sorption of naturally occurring uranium on weakly basic anion exchangers (WBA) have been investigated. Systematic investigations on the effects of various parameters show in general three important factors influencing the adsorption equilibrium. First, the sorption depends on the presence of competing anions, with sulfates showing the greatest influence. Second, the speciation of uranium (VI), which in carbonate-containing waters in a pH range between 6.5 and 9 exists mainly as anionic complexes UO₂(CO₃)₂^2- and UO₂(CO₃)₃^4-, is changed by calcium and bicarbonates. Calcium forms neutral complexes with uranium and carbonate, and with these complexes no ion exchange occurs. On the other hand, increasing concentrations of carbonate species support the formation of anionic uranyl complexes of higher charge, and an increased uranium uptake arises. Third, the effective capacity of WBA depends on the pH. With increasing pH, the amount of protonated functional groups decreases and the sorption capacity decreases.

It has been demonstrated that WBA sorb uranium very selectively out of drinking water. WBA Amberlite IRA 67 reached the uranium loading of 10 mg/g at the uranium concentration of 10 µg/L by sorption out of tap water at pH 7.     

Studies on the removal of Cobalt(II) from aqueous solutions by adsorption with Ficus benghalensis leaf powder through response surface methodology

Suitability of Ficus benghalensis leaf powder for the adsorptive removal of Cobalt(II) from aqueous solutions is exhaustively studied and is reported in this article. Experimentation based on response surface methodology is conducted to understand the interaction among the variables—metal ion concentration, adsorbent dosage, initial solution pH and temperature that are of significance in the treatment. A 20?mg?L^?1 of Cobalt(II) solution, treated with 25?g?L^?1 of adsorbent at a pH of 5.0 and a temperature of 303?K, yielded 98.73% removal of Cobalt(II). Langmuir isotherm proved to be a better model representation of the equilibrium. Adsorption kinetics is of pseudo second rate form. Maximum sorption capacity of F. benghalensis leaf powder, q_max, is found to be 5.65?mg?g^?1. Adsorption is endothermic and spontaneous in nature. Study on surface morphology is included in the study.