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     

Removal of 4‐chlorophenol from contaminated water using coconut shell waste pretreated with chemical agents

BACKGROUND: At concentrations higher than 1 mg L^?1, 4‐chlorophenol (4‐CP) is very toxic to living organisms, and if ingested beyond the permitted concentration it causes health disorders such as cancer and mutation. This laboratory study investigates treatment of contaminated water laden with 4‐CP using coconut shell charcoal (CSC) waste. Batch studies were conducted to study the effects of dose, pH, and equilibrium time on 4‐CP removal. To improve 4‐CP removal, surface modification of the adsorbent with TiO₂, HNO₃, and/or NaOH was undertaken. RESULTS: At an initial 4‐CP concentration of 25 mg L^?1 under optimized conditions (dose 13.5 g L^?1, pH 2.0; agitation speed 150 rpm and 50 min equilibrium time), the NaOH‐treated CSC demonstrated a greater removal of 4‐CP (71%) than those oxidized with HNO₃ (40%) and/or coated with TiO₂ (52%). The adsorption capacity of the NaOH‐treated CSC (54.65 mg g^?1) was higher than those treated with HNO₃ (23.13 mg g^?1) or coated with TiO₂ (48.42 mg g^?1). CONCLUSION: Although treatment results using the NaOH‐treated CSC alone were promising, the treated effluents were still unable to meet the required limit of less than 1 mg L^?1. Therefore, subsequent treatments are still required to complement the removal of 4‐CP from the wastewater. Copyright © 2010 Society of Chemical Industry     

Adsorption and heat‐energy‐aid desorption of cationic dye on a new thermo‐sensitive adsorbent: Methyl cellulose/calcium alginate beads

The adsorption and heat‐energy‐aid desorption of methylene blue (MB) on a thermo‐sensitive adsorbent of methyl cellulose/calcium alginate beads (MC/CABs) has been studied. The addition of methyl cellulose intensified the desorption ability of adsorbent, and boosted the difference of adsorption capacity of adsorbent between low temperature and high temperature. At the mass ratio of methyl cellulose to sodium alginate of 2:1, the difference of adsorption capacity of MC/CABs between 20 and 60°C reached 20.48 mg g^?1. The effects of temperature, time and initial MB concentration on adsorption performance were investigated in detail. The MB adsorption on MC/CABs followed the pseudo‐second‐order kinetic model. The equilibrium data was fitted well with Langmuir isotherm. The maximum adsorption capacity of 336.70 mg g^?1 exhibited MC/CABs had a good adsorption capability. Thermodynamic analyses showed high temperature was not favorable to MB adsorption, and MC/CABs had a distinct superiority in desorption of adsorbate with heat‐energy‐aid. Lastly, the possible mechanisms involving in adsorption and heat‐energy‐aid desorption were presented. POLYM. ENG. SCI., 56:1382–1389, 2016. © 2016 Society of Plastics Engineers     

Preparation of a surface molecular‐imprinted adsorbent for Ni2+ based on Penicillium chrysogenum

A new chitosan molecular‐imprinted adsorbent was prepared from the mycelium of waste biomass. The results showed that an adsorbent using Penicillium chrysogenum mycelium as the core material was better than one derived from peanut coat. The adsorption capacity of the surface‐imprinted adsorbent for Ni²⁺ was enhanced by increasing the chitosan concentration in the imprinting process. Epichlorohydrin was better than glutaraldehyde as a cross‐linking agent; the optimal imprinted Ni²⁺ concentration for preparing the surface‐imprinted adsorbent was 2 mg (Ni²⁺) g^?1 of mycelium. The adsorption capacity of the surface‐imprinted adsorbent was 42 mg g^?1 (at 200 mg dm^?3 initial metal ions concentration) and twice that of the mycelium adsorbent. The surface‐imprinted adsorbent can be reused for up to 15 cycles without loss of adsorption capacity. Copyright © 2005 Society of Chemical Industry     

Novel type of alginate gel‐based adsorbents for heavy metal removal

Various alginate gel‐based adsorbents were investigated for the removal of heavy metals: alginate beads, alginate capsules, and alginate gel‐coated adsorbent. Of these, alginate capsules showed the greatest Pb²⁺ uptake capacity of 1560 mg g^?1 of dry sodium alginate, and the alginate gel‐coated adsorbent, prepared simply by forming a thin alginate film on an inert matrix, achieved rapid adsorption equilibrium within 10 min. Adsorbed metals were readily removed from the alginate gel‐based adsorbents using eluents such as HNO₃ and could be reused for up to 10 adsorption–desorption cycles without marked loss of metal uptake capacity. Alginate gel‐coated adsorbents could be prepared in a dried state and have great application potential for the removal of heavy metals from contaminated water. Copyright © 2004 Society of Chemical Industry     

Cibacron Blue F3GA‐attached magnetic poly(2‐hydroxyethyl methacrylate) beads for human serum albumin adsorption

An affinity dye ligand, Cibacron Blue F3GA, was covalently attached onto magnetic poly(2‐hydroxyethyl methacrylate) (mPHEMA) beads for human serum albumin (HSA) adsorption from both aqueous solutions and human plasma. The mPHEMA beads, in the size range of 80 to 120 µm, were prepared by a modified suspension technique. Cibacron Blue F3GA molecules were incorporated on to the mPHEMA beads. The maximum amount of Cibacron Blue F3GA attachment was obtained as 68.3 µmol g^?1. HSA adsorption onto unmodified and Cibacron Blue F3GA‐attached mPHEMA beads was investigated batchwise. The non‐specific adsorption of HSA was very low (1.8 mg g^?1). Cibacron Blue F3GA attachment onto the beads significantly increased the HSA adsorption (94.5 mg g^?1). The maximum HSA adsorption was observed at pH 5.0. Higher HSA adsorption was observed from human plasma (138.3 mg HSA g^?1). Desorption of HSA from Cibacron Blue F3GA‐attached mPHEMA beads was obtained by using 0.1 M Tris/HCl buffer containing 0.5 M NaSCN. High desorption ratios (up to 98% of the adsorbed HSA) were observed. It was possible to re‐use Cibacron Blue F3GA‐attached mPHEMA beads without any significant decreases in their adsorption capacities. Copyright © 2004 Society of Chemical Industry     

Preparation and characteristics of a dummy molecularly imprinted polymer for phenol

A dummy molecularly imprinted polymers (DMIP) for phenol was synthesized by a thermal polymerization method with acrylamide as the functional monomer, ethylene dimethacrylate as the crosslinker, 2,2‐azobisisobutyronitrile as the free‐radical initiator, acetonitrile as the porogenic solvent, and sulfadiazine, a phenol analogue, as the template. In comparison to other adsorbents, the synthesized DMIP showed a higher capacity and rate of adsorption. The adsorption amount of the DMIP adsorbents for phenol reached 6.09 ± 0.15 mg/g, and the adsorption rate of the DMIP was about 0.406 ± 0.01 mg g^?1·min^?1. The results indicate that the Freundlich model fit the adsorption model of DMIP for phenol. The adsorption model of DMIP for phenol was multilayer adsorption. This showed that the DMIP synthesized by bulk polymerization could be used as a novel adsorbent for the removal of phenol from contaminated water. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Improved synthesis of a branched poly(ethylene imine)‐modified cellulose‐based adsorbent for removal and recovery of Cu(II) from aqueous solution

This study focuses on an improved synthesis of a branched poly (ethylene imine) (PEI)‐modified cellulose‐based adsorbent (Cell‐g‐PGMA‐PEI). We aim to improve the adsorbent capacity by reducing side reaction of epoxide ring opening during graft copolymerization of glycidyl methacrylate (GMA) onto cellulose which increases the content of epoxy groups, anchors to immobilize branched PEI moieties. FTIR spectra provided the evidence of successful graft copolymerization of GMA onto cellulose initiated by benzoyl peroxide (BPO) and modification with PEI. The amount of epoxy groups of Cell‐g‐PGMA was 4.35 mmol g^?1 by epoxy titration. Subsequently, the adsorption behavior of Cu(II) on cell‐g‐PGMA‐PEI in aqueous solution has been investigated. The data from the adsorption kinetic experiments agreed well with pseudo‐second‐order model. The adsorption isotherms can be interpreted by the Langmuir model with the maximum adsorption capacity of 102 mg g^?1 which was largely improved compared with the similar adsorbent reported. The dynamic adsorption capacity obtained from the column tests was 119 mg g^?1 and the adsorbent could be regenerated by HCl of 0.1 mol L^?1. Results indicate that the novel pathway for the synthesis of Cell‐g‐PGMA‐PEI exhibits significant potential to improve the performance of adsorbents in removal and recovery of Cu(II) from aqueous solution. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation of crosslinked β‐cyclodextrin polymer beads and their application as a sorbent for removal of phenol from wastewater

BACKGROUND: Phenols are commonly encountered in aqueous effluents from various manufacturing processes such as oil refineries, coke plants, and phenolic resin plants, and are toxic substances that should be removed from the aquatic environment. This paper reports on the preparation of beaded crosslinked β‐CyD polymers, and the removal of phenol by the β‐CyD adsorbent from raw industrial wastewater discarded from phenolic resin processing. RESULTS: Crosslinked β‐CyD prepolymer was synthesized by treatment of β‐CyD with hexamethylene diisocyanate (HDI) at a molar ratio of 1:8. The suspension of the resulting powdery prepolymer in aqueous sodium alginate was added dropwise into an aqueous calcium chloride solution to precipitate the spherical β‐CyD prepolymer gels. The spherical prepolymer gel was lyophilized and re‐crosslinked with HDI to provide the β‐CyD polymer beads. The physical properties of the beads were as follows: average diameter: 3.4 mm; average compressive strength: 2.17 MPa; porosity: 47.0%; specific surface area: 3.48 m² g^?1. The removal of phenol from raw industrial phenolic wastewater with the β‐CyD polymer beads was carried out in either a shaker or an upflow column at 25 °C. After seven episodes of accumulated adsorption, the initial phenol concentration of 89000 ppm decreased to as low as 350 ppm in the shaker and 490 ppm in the upflow column. CONCLUSION: Adsorbent [β‐CyD/HDI(1/8)]/HDI polymer beads having a good regular shape and high mechanical stability were newly prepared by a stepwise crosslinking method. The results of sorption experiments show that the beads exhibit high sorption capacities for phenolics in raw industrial wastewater. Copyright © 2008 Society of Chemical Industry     

Removal of aqueous phenolic compounds from a model system by oxidative polymerization with turnip (Brassica napus L var purple top white globe) peroxidase

Turnip roots, which are readily available in Mexico, are a good source of peroxidase, and because of their kinetic and biochemical properties have a high potential as an economic alternative to horseradish peroxidase (HRP). The efficiency of using turnip peroxidase (TP) to remove several different phenolic compounds as water‐insoluble polymers from synthetic wastewater was investigated. The phenol derivatives studied included phenol, 2‐chlorophenol, 3‐chlorophenol, o‐cresol, m‐cresol, 2,4‐dichlorophenol and bisphenol‐A. The effect of pH, substrate concentration, amount of enzyme activity, reaction time and added polyethylene glycol (PEG) was investigated in order to optimize reaction conditions. A removal efficiency ≥85% was achieved for 0.5 mmol dm^?3 phenol derivatives at pH values between 4 and 8, after a contact time of 3 h at 25 °C with 1.28 U dm^?3 of TP and 0.8 mmol dm^?3 H₂O₂. Addition of PEG (100–200 mg dm^?3) significantly reduced the reaction time required (to 10 min) to obtain >95% removal efficiency and up to 230% increase in remaining TP activity. A relatively low enzyme activity (0.228 U dm^?3) was required to remove >95% of three phenolic solutions in the presence of 100–200 mg dm^?3 PEG. TP showed efficient and fast removal of aromatic compounds from synthetic wastewaters in the presence of hydrogen peroxide and PEG. These results demonstrate that TP has good potential for the treatment of phenolic‐contaminated solutions. © 2002 Society of Chemical Industry     

Enhanced Cometabolic Transformation of 4‐Chlorophenol in the Presence of Phenol by Granular Activated Carbon Adsorption

Substrate inhibitions that manifest within the cometabolism system of 4‐chlorophenol (4‐cp) and phenol were alleviated through the application of granular activated carbon (GAC) in batch biodegradation. It was found that 4‐cp was preferentially adsorbed over phenol by the GAC and that 50% to 70% of the adsorption was achieved within the first two hours of contact. The kinetics of 4‐cp adsorption was also much faster than that of phenol, even when the co‐existing phenol was of a significantly higher initial concentration. As a result, competitive inhibition between the two compounds was minimized. Adsorption also caused a lowering of the phenol concentration in solution with a concomitant reduction in the substrate inhibition effect on cell growth. The addition of GAC benefited the biotransformation process through shortening the total degradation time for 600 mg L^?1 phenol and 100 mg L^?1 4‐cp from 42 h to 12 h; and it also made it possible for cells to survive and transform 600 mg L^?1 phenol and as high as 400 mg L^?1 4‐cp in free suspension cultures. Repeated operations in which GAC was reused showed that GAC could be regenerated by the cells, thus rendering the GAC incorporated process amenable to long term operations.     

Equilibrium and dynamic studies of the removal of As(III) and As(V) from contaminated aqueous systems using a functionalized biopolymer

BACKGROUND: A study of the removal of arsenic from a sample of actual groundwater using crosslinked xanthated chitosan is described. RESULTS: Removal of As(III) and As(V) was studied at pH 7.5 under equilibrium and dynamic conditions. The equilibrium data were fitted to Langmuir and Freundlich adsorption models and the various model parameters evaluated. The monolayer adsorption capacity from the Langmuir model for xanthated chitosan flakes (XCF) (As(V) 20.0 ± 0.56 mg g^?1; As(III) 33.0 ± 0.32 mg g^?1) were lower than obtained for xanthated chitosan granules (XCB) (As(V) 36.0 ± 0.52 mg g^?1; As(III) 48.0 ± 0.45 mg g^?1). Adsorption of As (V) was unaffected by the presence of other anions while in the case of As(III) the presence of sulfate and silicate caused a 26.5–50.9% decrease in adsorption. A sample (940 bed volumes) of a groundwater spiked with 200 µg L^?1 As(V) treated with XCF in column experiments reduced the arsenic concentration to < 10 µg L^?1. The adsorbent was also successfully applied for the removal of total inorganic arsenic down to < 10 µg L^?1 from real samples of arsenic‐contaminated groundwater. CONCLUSION: Xanthated chitosan was an efficient adsorbent for the removal of both forms of arsenic from groundwater under near neutral conditions. The presence of sulfur and the amino groups resulted in increased adsorption capacity of the sorbent. Copyright © 2012 Society of Chemical Industry     

Synthesis and characterization of magnetic beads containing aminated fibrous surfaces for removal of Reactive Green 19 dye: kinetics and thermodynamic parameters

BACKGROUND: Poly(HEMA‐co‐MMA) beads were prepared from 2‐hydroxyethyl‐methacrylate (HEMA) and methylmethacrylate (MMA) in the presence of FeCl₃. Thermal co‐precipitation of Fe(III) ions containing beads with Fe(II) ions was carried out under alkaline conditions. The magnetic beads were grafted with poly(glycidylmethacrylate; p(GMA)), and the epoxy groups of the grafted p(GMA) brushes were converted into amino groups by reaction with ammonia. RESULTS: The magnetic beads were characterized by surface area measurement, electron spin resonance (ESR), Mössbauer spectroscopy and scanning electron microscopy (SEM). The maximum adsorption of Reactive Green‐19 (RG‐19) dye on the p(GMA) grafted and amine modified magnetic beads was around pH 3.0. The adsorption capacity of magnetic beads was 84.6 mg dye g^?1. The effects of adsorbent dosage, ionic strength and temperature have also been reported. Batch kinetic sorption experiments showed that a pseudo‐second‐order rate kinetic model was applicable. CONCLUSION: The p(GMA) grafted and amine modified magnetic beads (adsorbent) were expected to have the advantage of mobility of the grafted chains in the removal of acidic dyes from aqueous solutions. The magnetic beads have potential as an adsorbent for removal of pollutants under various experimental conditions without significant reduction in their initial adsorption capacity. Copyright © 2011 Society of Chemical Industry     

Experimental improvement of preparation of acrylic acid‐modified middle deacetylated chitosan and its application in absorbing paraquat

Chitosan with 45% deacetylation (CS45) grafted poly (acrylic acid) (CS45‐g‐PAA) was synthesized and characterized as an adsorbent of paraquat. CS45‐g‐PAA copolymers were prepared using H₂O_2(aq) as an initiator and NH₄OH_(aq) as a promoter. The highest grafting percentage of 44.2% was obtained using the traditional kinetic method. However, a maximum grafting percentage of 52.6% was calculated for the central composite design (CCD). Experimental results based on the reaction conditions that were predicted from the CCD are consistent with theoretical calculations. The grafted copolymer was characterized by FTIR, BET, and SEM. A representative CS45‐g‐PAA copolymer was hydrolyzed to a salt type (CS45‐g‐PANa) and used in the adsorption of paraquat. The adsorption equilibrium data correlate more closely with the Langmuir isotherm than with the Freundlich equation. The maximum adsorption capacity of CS45‐g‐PANa is 396.7 mg/g‐adsorbent. This value clearly exceeds that of Fuller's earth and the activated carbon which is the most commonly used binding agent for paraquat. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Sorption capacity of a new generation granular activated carbon—Bio‐Sep® bead—and its use in a suspended growth bioreactor

BACKGROUND: A new generation granular activated carbon—Bio‐Sep® beads—consist of 25% polymer (Nomex) and 75% powdered activated carbon. The porous structure and high surface area of these beads make them suitable for sorbent in adsorption columns, and for immobilization media in bioreactors. The aim of this study was to study the sorption characteristics of Bio‐Sep® beads for methyl t‐butyl ether (MTBE) and t‐butyl alcohol (TBA), and to demonstrate the advantage of their usage in a suspended growth bioreactor. RESULTS: The maximum uptake capacity of Bio‐Sep® beads for MTBE and TBA, in the studied concentration range (10–100 mg L^?1), was observed to be 9.73 and 6.23 mg g^?1, respectively. A 52 h desorption experiment resulted in 13.6–42.2% MTBE and 33–53% TBA desorption corresponding to the initial solid phase concentrations of 1.68–9.73 mg g^?1 and 1.41–6.23 mg g^?1, respectively. The sorption of TBA on the Bio‐Sep® beads was significantly hindered by the presence of MTBE. The addition of 10 g Bio‐Sep® beads (dry weight) in a suspended growth bioreactor was able to eliminate the inhibitory effect of 150 mg L^?1 MTBE. CONCLUSIONS: At an equilibrium aqueous phase concentration (C_e) of 1 mg L^?1, the solid phase concentration (q_e) on Bio‐Sep® beads were observed as 1.44 and 0.47 mg g^?1 for MTBE and TBA, respectively. The results obtained in this study indicate that Bio‐Sep® beads have reasonable sorption and desorption characteristics, which can be successfully exploited for the removal/degradation of toxic organic pollutants in high rate bioreactors. Copyright © 2007 Society of Chemical Industry     

Preparation of gel resins and removal of copper and lead from water

A series of gel resins were prepared by polymerizing glycidyl methacrylate (GMA) and 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) and functionalizing with ammonia (NH₃) and tetraethylenepentamine (TEPA). The aminated gel resins were then used as an adsorbent for the removal of heavy metal ions (Cu²⁺ and Pb²⁺). These gel resins containing amino groups and chelating amino groups had excellent adsorptive properties for Cu²⁺ and Pb²⁺. The adsorption process reached equilibrium in 40 min, and the adsorption capacities of Cu²⁺ and Pb²⁺ were 75.0 mg g^?1 and 266.6 mg g^?1 for the NH₃‐aminated gel resins and 57.5 mg g^?1 and 330.6 mg g^?1 for the TEPA‐aminated gel resins, respectively. After five adsorption–desorption processes, the adsorption capacities only decreased slightly. Thus, these aminated gel resins can be used as effective adsorbents for aqueous heavy metal ions (Cu²⁺ and Pb²⁺). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44466.     

A new synthetic biofiltration material: poly(vinyl alcohol)/pig manure compost composite beads

Poly(vinyl alcohol) (PVA)/pig manure compost composite beads proved suitable as a biofilter material in a biofiltration process. The composite bead is a porous spherical particle with a diameter between 2.4 and 6.0 mm and a density of 0.96 g cm^?3. It contains 9.43 mg P g^?1 dry solid and 12.1 mg N g^?1 dry solid. The equilibrium moisture contents of the PVA/compost composite beads bed for adsorption and holding experiments are 50.5% and 54.6% by wet basis, respectively, which correspond to the optimal filter material required and could sustain the biological activity. The PVA/pig manure compost composite beads bed has higher moisture‐holding capacity and compression strength than the pig manure compost bed. The PVA/compost composite beads have buffer capacity and could keep the filter bed at pH 6.9–7.2 during operating. The percentage of ethyl acetate removed could stay at over 99% for 40 days of operation as the PVA/pig manure compost composite beads adsorbed inorganic nitrate nutrient. The maximum elimination capacity of the PVA/pig manure compost composite beads filters at the loading rate of 0.71 kg ethyl acetate m^?3‐bed h^?1 is 0.71 kg ethyl acetate m^?3‐bed h^?1. Copyright © 2005 Society of Chemical Industry     

Activated carbon derived from macadamia nut shells: an effective adsorbent for phenol removal

In this study, activated carbon based on the waste macadamia nut shells (MAC) was investigated for potential use as an adsorbent for phenol removal. The pseudo second-order kinetic model best described the adsorption process. The extent of the phenol adsorption was affected by the pH solution and the adsorbent dosage. Equilibrium data fitted well to the Langmuir model with a maximum adsorption capacity of 341 mg g^?1. The calculated thermodynamic parameters suggested that the phenol adsorption onto MAC was physisorptive, spontaneous and exothermic in nature. Phenol desorption from loaded adsorbent was achieved by using 0.1 mol L^?1 NaOH, ethanol (100 %) and deionized water.     

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     

Human serum albumin adsorption on poly[(glycidyl methacrylate)‐co‐(methyl methacrylate)] beads modified with a spacer‐arm‐attached L‐histidine ligand

Poly(GMA/MMA) beads were synthesized from glycidyl methacrylate (GMA) and methyl methacrylate (MMA) in the presence of a cross‐linker (i.e. ethyleneglycol dimethacrylate) (EGDMA) via suspension polymerization. The epoxy groups of the poly(GMA/MMA) beads were converted into amino groups with either ammonia or 1,6‐diaminohexane (i.e. spacer‐arm). An L ‐histidine ligand was then covalently immobilized on the aminated (poly(GMA/MMA)‐AH) and/or the spacer‐arm attached (poly(GMA/MMA)‐SAH) beads using glutaric dialdehyde as a coupling agent. Both affinity adsorbents were used in human serum albumin (HSA) adsorption/desorption studies under defined pH, ionic strength or temperature conditions in a batch reactor. The spacer‐arm attached affinity adsorbent resulted in an increase in the adsorption capacity to HSA when compared to the aminated counterpart (i.e. poly(GMA/MMA)‐AH). The maximum adsorption capacities of the affinity adsorbents were found to be significantly high, i.e. 43.7 and 80.2 mg g^?1 (of the beads), while the affinity constants, evaluated by the Langmuir model, were 3.96 × 10^?7 and 9.53 × 10^?7 mol L^?1 for poly(GMA/MMA)‐AH and poly(GMA/MMA)‐SAH, respectively. The adsorption capacities of the affinity adsorbents were decreased for HSA by increasing the ionic strength, adjusted with NaCl. The adsorption kinetics of HSA were analysed by using pseudo‐first and pseudo‐second‐order equations. The second‐order equation fitted well with the experimental data. Copyright © 2005 Society of Chemical Industry