Biosorption of copper(II) by nonliving lichen biomass of Cladonia rangiformis hoffm

Biosorption of heavy metals can be an effective process for the removal of heavy metal ions from aqueous solutions. In this study, the adsorption properties of lichen biomass of Cladonia rangiformis hoffm. for copper(II) were investigated by using batch adsorption techniques. The effects of initial metal ion concentration, initial pH, biosorbent concentration, stirring speed and contact time on biosorption efficiency were studied. In the experiments the optimum pH value was found out 5.0 which was the native pH value of solution. The experimental adsorption data were fitted to the Langmuir adsorption model. The highest metal uptake was calculated from Langmuir isotherm and found to be 7.6923 mg Cu(II)/g inactivated lichen at 15 degrees C. The results indicated that the biomass of C. rangiformis is a suitable biosorbent for removing Cu(II) from aqueous solutions.     

Biosorption of heavy metal ions from aqueous solution by red macroalgae

Biosorption is an effective process for the removal and recovery of heavy metal ions from aqueous solutions. The biomass of marine algae has been reported to have high biosorption capacities for a number of heavy metal ions. In this study, four species of red seaweeds Corallina mediterranea, Galaxaura oblongata, Jania rubens and Pterocladia capillacea were examined to remove Co(II), Cd(II), Cr(III) and Pb(II) ions from aqueous solution. The experimental parameters that affect the biosorption process such as pH, contact time and biomass dosage were studied. The maximum biosorption capacity of metal ions was 105.2mg/g at biomass dosage 10 g/L, pH 5 and contact time 60 min. The biosorption efficiency of algal biomass for the removal of heavy metal ions from industrial wastewater was evaluated for two successive cycles. Galaxaura oblongata biomass was relatively more efficient to remove metal ions with mean biosorption efficiency of 84%. This study demonstrated that these seaweeds constitute a promising, efficient, cheap and biodegradable sorbent biomaterial for lowering the heavy metal pollution in the environment.     

Adsorption properties of Congo Red from aqueous solution onto surfactant-modified montmorillonite

A series of surfactant-modified montmorillonites (MMT) were prepared using octyltrimethylammonium bromide (OTAB), dodecyltrimethylammonium bromide (DTAB), cetyltrimethylammonium bromide (CTAB) and stearyltrimethylammonium bromide (STAB), and the organification of MMT was proved by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron micrographic (SEM) and transmission electron microscope (TEM). The adsorption of Congo Red (CR) anionic dye from aqueous solution onto surfactant-modified MMT was carried out. Compared with MMT, the adsorption capacity of surfactant-modified MMT for CR was greatly enhanced and MMT modified with CTAB (2.0 CEC) exhibited the higher adsorption capacity. The effects of pH value of the dye solution, adsorption temperature, adsorption time and the initial dye concentration on the adsorption capacity of CR on CTAB-MMT have been investigated. The results showed that the adsorption kinetic of CR on CTAB-MMT could be best described by the pseudo-second-order model and that the adsorption isotherm of CR was in good agreement with the Langmuir equation. The IR spectra and SEM analysis also revealed that the adsorption of CTAB-MMT was a chemical adsorption process between CTAB and the NH(2), -N=N- and SO(3) groups of CR.     

Biosorption of methylene blue from aqueous solution by rice husk in a fixed-bed column

In this study, the ability of rice husk to adsorb methylene blue (MB) from aqueous solution was investigated in a fixed-bed column. The effects of important parameters, such as the value of initial pH, existed salt, the flow rate, the influent concentration of MB and bed depth, were studied. The Thomas model was applied to adsorption of MB at different flow rate, influent concentration and bed depth to predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design using non-linear regression. The bed-depth/service time analysis (BDST) model was also applied at different bed depth to predict the breakthrough curves. The two models were found suitable for describing the biosorption process of the dynamic behavior of the rice husk column. All the results suggested that rice husk as adsorbent to removal MB from solution be efficient, and the rate of biosorption process be rapid. When the flow rate was 8.2ml min(-1) and the influent concentration of MB was 50mgl(-1), the equilibrium adsorption biomass reached 4.41mgg(-1) according to Thomas model.     

Biosorption of methylene blue from aqueous solution by fallen phoenix tree's leaves

A new adsorbent, the fallen phoenix tree's leaf, has been investigated in order to remove methylene blue (MB) from aqueous solutions. Variables of the system, including contact time, leaf dose, solution pH, salt concentration and initial MB concentration, were adopted to study their effects on MB biosorption. The results showed that as the dose of leaf increased, the percentage of MB sorption increased accordingly. There was no significant difference about the quantity of MB adsorbed onto leaf as the pH was within the range 4.5-10.0. The salt concentration has negative effect on MB removal. The equilibrium data were analyzed using the Langmuir and the Freundlich isotherms. The results of non-linear regressive analysis are that the Langmuir isotherm is better fit than the Freundlich isotherm at different temperature according to the values of determined coefficients (R(2)) and chi(2)-statistic (SS). The Langmuir monolayer saturation capacities of MB adsorbed onto leaf are 80.9, 83.8, 89.7mgg(-1) at 295, 309 and 323K, respectively. Using the equilibrium concentration contents obtained at different temperatures, various thermodynamic parameters, such as DeltaG degrees , DeltaH degrees and DeltaS degrees , have been calculated. The thermodynamics parameters of MB/leaf system indicate spontaneous and endothermic process. It was concluded that an increase in temperature be advantage to adsorb MB onto leaf.     

Biosorption of uranium(VI) from aqueous solution using calcium alginate beads

In this paper, sorption potentials of uranium ions were studied using alginate polymer beads in diluted aqueous solutions. The ability of alginate beads to adsorb uranium(VI) from aqueous solution has been studied at different optimized conditions of pH, U(VI) concentration, contact time, biomass dosage and temperature. In order to determine the adsorption characteristics, Langmuir, Freundlich, and Dubinin–Radushkevich adsorption isotherms were applied to the adsorption data. The thermodynamic parameters such as variations of enthalpy ΔH, entropy ΔS and variation of Gibbs free energy ΔG were calculated from the slope and intercept of ln K_d vs. 1/T plots. The results suggested that alginate beads could be suitable as a sorbent material for adsorption and removal of uranium ions from dilute aqueous solutions.     

Biosorption of copper(II) and lead(II) from aqueous solution by chaff in a fixed-bed column

In this article, the ability of chaff to adsorb heavy metal ions from aqueous solution was investigated in a fixed-bed column. The effect of important parameters, such as the value of pH, the flow rate, the influent concentration of solution and the effect of coexistence ions, was studied. Also the adsorption/desorption recycles of chaff were shown, and the results indicated that chaff could be recycled to remove heavy metal ions. The Thomas model was applied to adsorption of copper and lead at different flow rate and different influent concentration to predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design. The model was found suitable for describing the biosorption process of the dynamic behavior of the chaff column. All the results suggested that chaff as adsorbent to removal heavy metal ions from solution prove efficient, and the rate of biosorption process is speedy. Furthermore, the efficiency of adsorption is high. When the flow rate was 3.6 ml min(-1) and the influent concentration of copper and lead was 14.82 mg l(-1) and 50.12 mg l(-1) respectively, the equilibrium adsorption biomass reached 1.98 mg g(-1) and 6.72 mg g(-1), respectively. The competitive adsorption for lead and copper was studied. Moreover the total adsorbing capability of chaff did not decrease when there were both copper(II) and lead(II) in solution.     

Biosorption of Cr(III) from aqueous solution using algal biomass spirogyra spp

In the present investigation, a fresh water green algae spirogyra spp. was used as an inexpensive and efficient biosorbent for Cr(III) removal from aqueous solution. The algal biomass was treated with 0.1M NaOH, 0.2M CaCl(2) and 5% HCHO. The biosorption efficiency was compared with untreated biomass. The effects of various physico-chemical parameters were studied, e.g. pH 3.0-6.0, initial metal ions concentration 20-150mgL(-1), algal dose 1.0-3.0gL(-1), and contact time 15-180min, respectively. Biosorption of Cr(III) is highly pH dependent. Maximum 81.02% adsorption of Cr(III) was observed with 0.2M CaCl(2) treated biomass at pH 5.0. Removal of Cr(III) was more than 70% in 45min of contact time with different treated and untreated algal biomass at concentration 30mgL(-1). Maximum metal uptake (Q(max)) was observed as 30.21mgg(-1) with 0.2M CaCl(2) treated algal biomass indicate good biosorbents than other treated and untreated biomass. The high values of correlation coefficient (r(2)<0.90) indicate equilibrium data of treated and untreated form of algal biomass well fitted in Freundlich than Langmuir isotherms model equations.     

Removal of cationic dyes from aqueous solution by adsorption on peanut hull

The potential feasibility of peanut hull particle for removal of three cationic dyes (methylene blue, brilliant cresyl blue and neutral red) from aqueous solution was investigated. The effects of various experimental parameters were examined and optimal experimental conditions were decided. Above the value of initial pH 4, three dyes studied could be removed effectively. The isothermal data fitted the Langmuir model or Freundlich model. The adsorption processes followed the pseudo-first-order rate kinetics. The results in this study indicated that peanut hull was an attractive candidate for removing cationic dyes from dye wastewater.     

Biosorption of mercury from aqueous solutions by powdered leaves of castor tree (Ricinus communis L.)

A new biosorbent produced from castor leaves powder [Ricinus communis L.] was used to remove mercury(II) from aqueous solutions. The initial mercury concentrations, contact time and initial pH were evaluated. The ability of castor leaves to remove mercury at various pH (2-8) was studied. The maximum capacity (Qmax) of biomass was found to be 37.2mg Hg(II)/g at pH 5.5. Biosorption equilibrium was established in approximately 1h. The equilibrium data were described well by Langmuir and Freundlich models. The adsorbed mercury on biomass was desorbed using 10 ml of 4M HCl solution. The biomass could be reused for other biosorption assays. The ability of biomass to adsorb mercury(II) in a column was investigated. These studies consider the possibility of using leaves of castor tree as an inexpensive adsorbent for the removal of Hg(II) from contaminated chemical and mining industry wastewaters. It is also suggested that the dried biomass might be simply kept and used in a very low cost metal ion removal system.     

Biosorption of Hg from aqueous solutions by crab carapace

Carapace from the edible crab was assessed for the biosorption of Hg from aqueous solutions. Batch adsorption studies were used to determine the effects of contact time, pH, concentration, particle size and Cu(II) as a co-ion. The removal of Hg was fast and efficient, attaining >80.0% from 500 mg/L by 60 min. Specific uptake increased from 0.1 to 13.0mg/g as initial concentration increased from 0.5 to 1000 mg/L while the removal efficiency decreased from 100.0% over the 0.5-10.0mg/L range to 65.0% at 1000 mg/L. As particle size decreases from >2.5 to <0.15 mm, the Hg uptake increased from 1.4 to 8.3mg/g. In binary metal solutions, Cu(II) reduced the Hg removal by 80.0% while the presence of Hg increased Cu(II) removal by approximately 7.0%. Crab carapace is a readily available alkaline waste and easily processed into durable granular forms. Therefore, it offers potential as a low-cost alternative to commercial adsorbents or as a complimentary polishing process for the removal of Hg from acidic solutions.     

Synthesis,characterization and kinetic of a surfactant-modified bentonite used to remove As(III) and As(V) from aqueous solution

In this study, organobentonites were prepared by modification of bentonite with various cationic surfactants, and were used to remove As(V) and As(III) from aqueous solution. The results showed that the adsorption capacities of bentonite modified with octadecyl benzyl dimethyl ammonium (SMB3) were 0.288 mg/g for As(V) and 0.102 mg/g for As(III), which were much higher compared to 0.043 and 0.036 mg/g of un-modified bentonite (UB). The adsorption kinetics were fitted well with the pseudo-second-order model with rate constants of 46.7 × 10⁻³ g/mg h for As(V) and 3.1 × 10⁻³ g/mg h for As(III), respectively. The maximum adsorption capacity of As(V) derived from the Langmuir equation reached as high as 1.48 mg/g, while the maximum adsorption capacity of As(III) was 0.82 mg/g. The adsorption of As(V) and As(III) was strongly dependent on solution pH. Addition of anions did not impact on As(III) adsorption, while they clearly suppressed adsorption of As(V). In addition, this study also showed that desorbed rates were 74.61% for As(V) and 30.32% for As(III), respectively, after regeneration of SMB3 in 0.1 M HCl solution. Furthermore, in order to interpret the proposed absorption mechanism, both SMB3 and UB were extensively characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analyses.     

The adsorption of cationic dye from aqueous solution onto acid-activated andesite

The adsorption of cationic dye (i.e., methylene blue) onto acid-activated andesite in aqueous solution was studied in a batch system with respect to its kinetics as a function of agitation speed, initial adsorbate concentration, pH, and adsorbent mass. It was found that the resulting acid-activated adsorbent possessed a mesoporous structure with BET surface areas at around 60m(2)/g. The surface characterization of acid-activated andesite was also performed using the zeta-potential measurements, indicating that the charge sign on the surface of the andesite should be negative in a wide pH range (i.e., 3-11). Furthermore, a simplified kinetic model, pseudo-second-order, was tested to investigate the adsorption behaviors of methylene blue onto the clay samples treated under different process conditions. It was found that the adsorption process could be well described with the model. The adsorption capacity parameter of the model obtained in the present work was significantly in line with the process parameters.     

Biosorption of Cu(II) from aqueous solutions by mimosa tannin gel

The biosorption of Cu(II) from aqueous solutions by mimosa tannin resin (MTR) was investigated as a function of particle size, initial pH, contact time and initial metal ion concentration. The aim of this study was to understand the mechanisms that govern copper removal and find a suitable equilibrium isotherm and kinetic model for the copper removal in a batch reactor. The experimental isotherm data were analysed using the Langmuir, Freundlich and Temkin equations. The equilibrium data fit well in the Langmiur isotherm. The experimental data were analysed using four sorption kinetic models -- the pseudo-first- and second-order equations, and the Elovich and the intraparticle diffusion equation -- to determine the best fit equation for the biosorption of copper ions onto mimosa tannin resin. Results show that the pseudo-second-order equation provides the best correlation for the biosorption process, whereas the Elovich equation also fits the experimental data well. Thermodynamic parameters such as the entropy change, enthalpy change and Gibb's free energy change were found out to be 153.0 J mol(-1)K(-1), 42.09 kJ mol(-1) and -2.47 kJ mol(-1), respectively.     

Biosorption of 2,4-dichlorophenol from aqueous solution by Phanerochaete chrysosporium biomass: isotherms, kinetics and thermodynamics

The biosorption of 2,4-dichlorophenol (2,4-DCP) from aqueous solution on non-living mycelial pellets of Phanerochaete chrysosporium was studied with respect to pH, initial concentration of 2,4-DCP, temperature and pellet size. The fungal biomass exhibited the highest sorption capacity of 4.09 mg/g at an initial pH of 5.0, initial 2,4-DCP concentration of 50.48 mg/l, 25 degrees C and a pellet size of 1.0-1.5 mm in the investigated pH 2.0-11.0, initial concentrations of 5-50 mg/l, temperature 25-50 degrees C, and pellet size of 1.0-2.5 mm. The Freundlich model exhibited a slightly better fit to the biosorption data of 2,4-DCP than the Langmuir model. The biosorption of 2,4-DCP to biomass followed pseudo second-order adsorption kinetics. The second-order kinetic constants decreased with increasing temperature, and the apparent activation energy of biosorption was estimated to be -16.95 kJ/mol. The thermodynamic analysis indicates that the biosorption process was exothermic and that the adsorption of 2,4-DCP on P. chrysosporium might be physical in nature. Both intraparticle diffusion and kinetic resistances might affect the adsorption rate and that their relative effects varied with operation temperature in the biosorption of 2,4-DCP by mycelial pellets.     

Biosorption of total chromium from aqueous solution by red algae (Ceramium virgatum): equilibrium, kinetic and thermodynamic studies

This study focused on the biosorption of total chromium onto red algae (Ceramium virgatum) biomass from aqueous solution. Experimental parameters affecting biosorption process such as pH, contact time, biomass dosage and temperature were studied. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models were applied to describe the biosorption isotherms. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The biosorption capacity of C. virgatum biomass for total chromium was found to be 26.5 mg/g at pH 1.5 and 10 g/L biomass dosage, 90 min equilibrium time and 20 °C. From the D–R isotherm model, the mean free energy was calculated as 9.7 kJ/mol, indicating that the biosorption of total chromium was taken place by chemisorption. The calculated thermodynamic parameters (ΔG°, ΔH°and ΔS°) showed that the biosorption of total chromium onto C. virgatum biomass was feasible, spontaneous and exothermic at 20–50 °C. Kinetic evaluation of experimental data showed that the biosorption processes of total chromium followed well pseudo-second-order kinetics.     

Biosorption of palladium(II) from aqueous solution by moss (Racomitrium lanuginosum) biomass: equilibrium, kinetic and thermodynamic studies

Arsenite (As(III)) and arsenate (As(V)) removal by direct contact membrane distillation (DCMD) were investigated with self-made polyvinylidene fluoride (PVDF) membranes in the present work. Permeability and ion rejection efficiency of the membrane were tested before the arsenic removal experiments. A maximum permeate flux 20.90 kg/m(2)h was obtained, and due to the hydrophobic property, the PVDF membrane had high rejection of inorganic anions and cations which was independent of the solution pH and the temperature. The experimental results indicated that DCMD process had higher removal efficiency of arsenic than pressure-driven membrane processes, especially for high-concentration arsenic and arsenite removal. The experimental results indicated that the permeate As(III) and As(V) were under the maximum contaminant limit (10 microg/L) until the feed As(III) and As(V) achieved 40 and 2000 mg/L, respectively. The 250 h simultaneous DCMD performance of 0.5mg/L As(III) and As(V) solution was carried out, respectively. The permeate arsenic was not detected during the process which showed the PVDF membrane had stable arsenic removal efficiency. Membrane morphology changed slightly after the experiments, however, the permeability and the ion rejection of the membrane did not change.     

Chromium(VI) adsorption from aqueous solution onto Moroccan Al-pillared and cationic surfactant stevensite

Batch adsorption of the chromium(VI) onto Moroccan stevensite pillared by Keggin aluminium hydroxypolycation (Al-stevensite) and cationic surfactant cetyltrimethylammoniumbromide (CTA-stevensite) was investigated. The results showed that the CTA-stevensite has a higher affinity than that of Al-stevensite for chromium(VI) adsorption. The adsorption capacities for natural stevensite, Al-stevensite and CTA-stevensite calculated according to the Dubinin-Kaganer-Radushkevich isotherm (DKR) are 13.7, 75.4 and 195.6mmolkg(-1), respectively. The study of the pH effect showed that the optimal range corresponding to the Cr(VI) maximum adsorption on Al-stevensite is pH 3.5-6 and that on CTA-stevensite is pH 2-6. The adsorption rates evaluated according to the pseudo-second-order model are 7.2, 207.2 and 178.5mmolkg(-1)min(-1) for the natural stevensite, Al-stevensite and CTA-stevensite, respectively. The low values of the adsorption energy calculated by (DKR) suggest that anion exchange is the main mechanism that governs the chromate adsorption.     

Biosorption of Cr (VI) from aqueous solutions by biomass of Agaricus bisporus

In this study, biosorption of Cr (VI) ion was investigated by using biomass of Agaricus bisporus (a species of mushroom) in a temperature and shaking speed controlled shaker. The effect of shaking speed, biomass concentration, initial metal ion concentration and initial pH on biosorption yield was determined and the fitness of biosorption data for Freundlich and Langmuir adsorption models was investigated. Optimum biosorption conditions were found to be pH 1, C0=50 mg/l, m=10 g/l, shaking speed=150 rpm, T=20 degrees C Cr (VI), respectively. It was found that biosorption of Cr (VI) ions onto biomass of A. bisporus was better suitable to Freundlich adsorption model than Langmuir adsorption model. The correlation coefficients for the second-order kinetic model obtained were found to be 0.999 for all concentrations. These indicate that the biosorption system studied belongs to the second-order kinetic model.     

Biosorption of cadmium(II) from aqueous solution by red algae (Ceramium virgatum): equilibrium, kinetic and thermodynamic studies

The biosorption characteristics of Cd(II) ions using the red alga (Ceramium virgatum) were investigated. Experimental parameters affecting the biosorption process such as pH, contact time, biomass dosage and temperature were studied. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherms. The biosorption capacity of C. virgatum biomass for Cd(II) ions was found to be 39.7 mg/g. From the D-R isotherm model, the mean free energy was calculated as 12.7 kJ/mol, indicating that the biosorption of Cd(II) the metal ions was taken place by chemisorption. The calculated thermodynamic parameters (DeltaG degrees , DeltaH degrees and DeltaS degrees ) showed that the biosorption of Cd(II) ions onto C. virgatum was feasible, spontaneous and exothermic at 293-323 K. Evaluation of experimental data in terms of biosorption kinetics showed that the biosorption of Cd(II) C. virgatum followed well pseudo-second-order kinetics.