Arsenic and antimony desorption in water treatment processes: Scaling up challenges with emerging adsorbents.

The metalloids arsenic (As) and antimony (Sb) belong to the pnictogen group of the periodic table; they share many characteristics, including their toxic and carcinogenic properties; and rank as high-priority pollutants in the United States and the European Union. Adsorption is one of the most effective techniques for removing both elements and desorption, for further reuse, is a part of the process to make adsorption more sustainable and feasible. This review presents the current state of knowledge on arsenic and antimony desorption from exhausted adsorbents previously used in water treatment, that has been reported in the literature. The application of different types of eluents to desorb As and Sb and their desorption performance are described. The regeneration of saturated adsorbents and adsorbate recovery techniques are outlined, including the fate of spent media and possible alternatives for waste disposal of exhausted materials. Future research directions are discussed, as well as current issues including the lack of environmental impact analysis of emerging adsorbents.

Efficient removal of arsenic from aqueous solution by continuous adsorption onto iron-coated cork granulates.

The search for low-cost technologies for arsenic removal from water is in high demand due to its human toxicity, even at low concentrations. Adsorption can be a cost-effective water treatment technique if applied with inexpensive materials. Arsenic continuous removal by adsorption onto an alternative modified biosorbent, iron-coated cork granulates (ICG), was investigated in this work. Results showed that most experimental parameters of breakthrough curves (BTC) depend on flow rate, bed height, pH, and initial arsenic concentration. The temperature did not significantly affect arsenate removal in continuous mode; however, the adsorption capacity was affected in batch mode. The thermodynamic parameters suggest that the adsorption process is spontaneous and endothermic. The maximum adsorption capacity of ICG for As(V) removal at pH 3 was 4.2 ±â€¯0.3 mg g-1, calculated by Yan model fit (R2 = 0.981), and for As(III) at pH 9 was 1.6 ±â€¯0.2 mg g-1 (R2 = 0.994). ICG were able to treat As(V) from 100 µg L-1 to under 10 µg L-1 and 50 µg L-1 for 895 and 1633 bed volumes, and As(III) for 569 and 861 bed volumes, respectively, both at pH 7. The application of ICG in arsenic oxyanions remediation was found to be effective under various conditions.

Tannin-based coagulants: Current development and prospects on synthesis and uses.

Population growth, industrialization, urbanization, and agriculture lead to a decrease in the availability of clean water. Coagulation/flocculation is one of the most common operations in water, urban wastewater, and industrial effluents treatment systems. Usually, this process is achieved using conventional coagulants that have their performance affected by pH, are poorly biodegradable, produce a huge volume of sludge, and are associated with degenerative diseases. As a substitute for these chemicals, natural coagulants have been highly researched for the last ten/fifteen years, especially the tannin-based (TB) ones. This review paper highlights the advantages of using these greener products to treat different types of water, wastewater, and effluents, especially from dairy, cosmetics, laundries, textile, and other industries. TB coagulants can successfully remove turbidity, color, suspended solids, soluble organic (chemical/biochemical oxygen demand) and inorganic matter (total phosphate, and heavy metals), and microorganisms. TB coagulants are compatible with other treatment technologies and can be used as coagulant-aid to reduce the consumption of chemicals. TB coagulants can reduce operating costs of water treatment due to less alkalinity consumption, as pH adjustment is sometimes unnecessary, and the production of a smaller volume of biodegradable sludge. TB coagulants can be synthesized by valorizing wastes/by-products, from the bark of some specific trees and skins/pomace of different fruits and vegetables. The strengths, weaknesses, opportunities, and threats (SWOT) on TB coagulants are discussed. The progress of TB coagulants is promising, but some threats should be overcome, especially on tannin extraction and cationization. The market competition with conventional coagulants, the feasibility of application in real waters, and the reluctance of the industries to adapt to new technologies are other weaknesses to be surpassed.

Antimony removal from water by pine bark tannin resin: Batch and fixed-bed adsorption.

Antimony is present in water by natural causes but is also mobilized in the environment by anthropogenic activities, particularly mining. Considering its toxicological behavior, antimony removal from contaminated groundwater and mine effluents is necessary. In this work, Sb(III) and Sb(V) removal from aqueous solution was studied using a resin prepared from pine bark tannins. Subsequent iron loading of the tannin resin was tested, but this chemical modification was shown not to improve adsorptive properties. Tannin resin (unmodified form) presented a good ability to uptake antimony, with maximum adsorption capacities, evaluated in batch mode, of 30-33 mg g-1 (Sb(III), pH 6) and 16-47 mg g-1 (Sb(V), pH 2), depending on the particle size. The performance of the adsorbent was not affected by high levels of sulfate, which characterize most mining-impacted waters, but depending on Sb-load of the water it could be moderately affected by metal cations coexisting in solution. The applicability of the tannin resin on Sb(III) uptake was confirmed in continuous fixed-bed experiments. Breakthrough curves were obtained for different inlet adsorbate concentrations, bed heights, flow rates and aqueous media (distilled water and a simulated mine effluent). The adsorptive capacity of the tannin resin was practically maintained and adsorbent usage rates as low as 0.11 kg m-3 were determined to treat efficiently (90% removal) 1 mg-Sb(III) L-1 contaminated water. Overall, tannin resin is a bio-derived sorbent that shows affinity for antimony in both redox states, being stable in pH conditions commonly found in Sb-contaminated waters.

Establishing the state-of-the-art on the adsorption of coexisting pnictogens in water: A literature review.

The occurrence of pnictogens, namely phosphorus, arsenic, and antimony, can be observed in soils, sediments and mining areas, and their coexistence requires a multifaceted approach to the design of adsorption systems to maximize their simultaneous removal efficiency. Therefore, this work aims to provide an extensive literature review of P, As, and Sb adsorption in multicomponent systems and the statistical treatment of the quantitative results. Binary As-P systems have been the most studied in the literature. The oxidation state did not significantly affect the P influence in As adsorbed amount (p = 0.955), but this influence was correlated with the As:P ratio (p < 0.05). A few works have explored As-Sb and Sb-P systems, demonstrating that effective treatments for As do not always reveal a good removal efficiency of the other pnictogens. The Sb adsorbed amount was significantly less affected in the trivalent than in the pentavalent state in both As-Sb and Sb-P systems (p < 0.05). Most of the interactions were competitive, with a few studies reporting synergistic effects for Sb due to the presence of the other elements. Many topics have been identified as lacking in-depth research: ternary As-Sb-P systems, the effect of concentration ratios, pH, and redox conditions (namely those that lead to trivalent species' prevalence), the surface interactions with materials other than iron oxides, and the influence of other aqueous components. This review provides a first step in gathering the relevant literature and approaching the study of adsorption treatment methodology as a complex subject involving many factors.

Multicomponent adsorption of pentavalent As, Sb and P onto iron-coated cork granulates.

The assessment of multicomponent adsorption of pentavalent metalloids is important since they are often found together in groundwaters and mining runoff. For this purpose, adsorption of As(V), Sb(V) and P(V) onto iron-coated cork granulates was studied in binary and ternary systems. Data from equilibrium and kinetic studies revealed that uptake of these contaminants is a multilayer, heterogeneous process well described by Freundlich, extended Freundlich and Elovich models. Most of the observed interactions are competitive and were related to the chemical structure and aqueous behaviour of each anion. Sb(V) adsorption was found to be most impaired and P(V) uptake the least affected by the presence of other pentavalent anions. The aggravation in the reduction of adsorbed amount from binary to ternary solution was more prominent for As(V) than Sb(V). Sb(V) adsorption outweighed that of the other pnictogens in acidic solutions, but in neutral conditions As(V) or P(V) adsorption may predominate instead. P(V) adsorption was the most sensitive to electrolyte addition, namely Ca salts, which may promote precipitation of calcium phosphates. This work provides useful insights regarding the design of adequate adsorption treatment systems for the simultaneous treatment of pentavalent metalloids.

Tannin-Adsorbents for Water Decontamination and for the Recovery of Critical Metals: Current State and Future Perspectives.

Biosorption is known as an effective way to clean-up water from organic and inorganic contaminants and has also emerged as a promising technology to recover critical substances. Tannins are renewable materials, coming from multiple vegetable sources. A variety of biosorbents have been developed from tannins, including tannin resins, rigid foams, composites with mesoporous silica, cellulose, collagen, and magnetic adsorbents. These materials have shown an excellent ability to uptake heavy-metal cations (Cd(II), Cu(II), Pb(II), Ni(II), Cr(III)), owning to the chelating ability provided by the plentiful adjacent hydroxyl groups. In addition, tannin-adsorbents have shown exceptional ability to remove Cr(VI), and to uptake Au(III) and Pd(II) from strong acidic solutions, which has evident application in the recovery of precious metals from e-wastes leaching. The fact that tannin-adsorbents can reduce the oxidation state of these adsorbates to Cr(III) and to elemental species of Au and Pd is interesting. Adsorption of dyes, surfactants, pharmaceuticals and antimony is also feasible, but the removal of certain metalloid species, such as arsenic and phosphate, seems to be limited even after applying chemical modifications. This article presents a systematic review on the preparation of tannin-adsorbents and their application in water decontamination and in the recovery of critical metals.

Bioadsorptive removal of Pb(II) from aqueous solution by the biorefinery waste of Fucus spiralis.

In the context of developing the circular economy that enables a more sustainable use of the available resources and minimum waste generation, marine macroalgae have attracted the attention of researchers and industry due to its potential as a renewable resource. The current work aims to contribute to the design of a complete biorefinery processing, using Fucus spiralis seaweed (brown division) as starting material, and to determine the potential of the derived waste as biosorbent of heavy metals in aqueous solution. The macroalgae waste was obtained after the sequential separation of polyphenols, fucoidan and alginate extracts from F. spiralis. The capacity of F. spiralis waste for Pb(II) removal was successfully tested through biosorption tests. The uptake of Pb(II) was found to be very fast (few hours to achieve equilibrium). Tests performed with an initial metal concentration of 20 mg/L established the best adsorbent dosage (0.50 g/L) and an optimum pH of 4.5. In these conditions, lead was almost completely removed from the aqueous solution. Maximum adsorption capacity predicted by Langmuir model was 132 ±â€¯14 mg/g (pH 4.5 ±â€¯0.5, 20 °C). Desorption studies were conducted with different possible eluents. The best results were obtained with EDTA 0.1 mol/L, generating a 95 ±â€¯4% desorption. F. spiralis biomass can therefore be submitted to a complete biorefinery processing and design in the attempt to fulfil the "zero-waste" concept.

Arsenate and arsenite adsorption onto iron-coated cork granulates.

There is a growing demand for low-cost, effective adsorbents for arsenic removal from water intended for human consumption in affected rural areas. This work presents a novel adsorbent based on the coating of cork granulates with iron (oxy)hydroxides for the removal of As(III) and As(V) from aqueous matrices. A 26-3 fractional factorial design was used to determine the optimal conditions for the iron coating procedure. The optimal adsorbent was produced by coating low-density cork granulates with iron (oxy)hydroxides precipitated from a 0.05 mol L-1 FeCl3 solution at pH 7, 20 °C temperature and 20 g L-1 S/L ratio, in a single coating cycle. Arsenic adsorption was found to be dependent on pH, with inverse trends for As(III) and As(V). The iron leaching from the adsorbent was also taken into account to select the optimum pH, which was pH 9 for As(III) and pH 3 for As(V). Adsorption kinetics were better described by the pseudo-second-order model for As(III) and the Elovich model for As(V). Equilibrium was reached in 16 h for As(III) at pH 9 and 48 h for As(V) at pH 3. The isotherm models indicated different adsorption behaviours for As(III) and As(V), with better fits by Langmuir and Freundlich models, respectively. The Langmuir maximum adsorption capacity of iron-coated cork adsorbent for As(III) at pH 9 was 4.9 ±â€¯0.3 mg g-1. However, at low equilibrium concentrations, As(V) adsorption was higher than As(III) (e.g. 2.1 ±â€¯0.2 mg g-1 in equilibrium with 0.16 ±â€¯0.03 mg L-1). Speciation studies and XPS analyses indicated that no substantial oxidation of As(III) to As(V) occurred during the adsorption process. The study shows that iron coating can enhance both arsenate and arsenite adsorption capacity of cork materials, leading to an innovative natural adsorbent with high resilience and stability, with possible application in arsenic remediation.

Arsenic removal from water using iron-coated seaweeds.

Arsenic is a semi-metal element that can enter in water bodies and drinking water supplies from natural deposits and from mining, industrial and agricultural practices. The aim of the present work was to propose an alternative process for removing As from water, based on adsorption on a brown seaweed (Sargassum muticum), after a simple and inexpensive treatment: coating with iron-oxy (hydroxides). Adsorption equilibrium and kinetics were studied and modeled in terms of As oxidation state (III and V), pH and initial adsorbate concentration. Maximum adsorption capacities of 4.2 mg/g and 7.3 mg/g were obtained at pH 7 and 20 °C for arsenite and arsenate, respectively. When arsenite was used as adsorbate, experimental evidences pointed to the occurrence of redox reactions involving As(III) oxidation to As(V) and Fe(III) reduction to Fe(II), with As(V) uptake by the adsorbent. The proposed adsorption mechanism was then based on the assumption that arsenate was the adsorbed arsenic species. The most relevant drawback found in the present work was the considerable leaching of iron to the solution. Arsenite removal from a mining-influenced water by adsorption plus precipitation was studied and compared to a traditional process of coagulation/flocculation. Both kinds of treatment provided practically 100% of arsenite removal from the contaminated water, leading at best in 12.9 µg/L As after the adsorption and precipitation assays and 14.2 µg/L after the coagulation/flocculation process.

Water quality modelling of Lis River, Portugal.

The aim of the study was to predict the impact of flow conditions, discharges and tributaries on the water quality of Lis River using QUAL2Kw model. Calibration of the model was performed, based on data obtained in field surveys carried out in July 2004 and November 2006. Generally the model fitted quite well the experimental data. The results indicated a decrease of water quality in the downstream area of Lis River, after the confluence of Lena, Milagres and Amor tributaries, as a result of discharges of wastewaters containing degradable organics, nutrients and pathogenic organisms from cattle-raising wastewaters, domestic effluents and agricultural runoff. The water quality criteria were exceeded in these areas for dissolved oxygen, biochemical oxygen demand, total nitrogen and faecal coliforms. Water quality modelling in different scenarios showed that the impact of tributaries on the quality of Lis River water was quite negligible and mainly depends on discharges, which are responsible by an increase of almost 45, 13 and 44 % of ultimate carbonaceous biochemical oxygen demand (CBOD(u)), ammonium nitrogen and faecal coliforms, for winter simulation, and 23, 33 and 36 % for summer simulation, respectively, when compared to the real case scenario.

Use of cork powder and granules for the adsorption of pollutants: a review.

Cork powder and granules are the major subproducts of the cork industry, one of the leading economic activities in Portugal and other Mediterranean countries. Many applications have been envisaged for this product, from cork stoppers passing through the incorporation in agglomerates and briquettes to the use as an adsorbent in the treatment of gaseous emissions, waters and wastewaters. This paper aims at reviewing the state of the art on the properties of cork and cork powder and their application in adsorption technologies. Cork biomass has been used on its original form as biosorbent for heavy metals and oils, and is also a precursor of activated carbons for the removal of emerging organic pollutants in water and VOCs in the gas phase. Through this literature review, different potential lines of research not yet explored can be more easily identified.

Water quality in Lis river, Portugal.

In the past 30 years, the Lis river basin has been subjected to constant ecological disasters mainly due to piggery untreated wastewater discharges. The aim of this study was to evaluate the effect of existing domestic, agricultural, and industrial activities on the water quality, and to propose a watershed plan to protect and manage surface water resources within the Lis river basin. For this purpose, 16 monitoring stations have been strategically selected along the Lis river stretch and its main tributaries to evaluate the water quality in six different sampling periods (2003­2006). All samples were characterized in terms of organic material, nutrients, chlorophyll, and pathogenic bacteria. Generally, the Lis river presents poor water quality, according to environmental quality standards for surface water, principally in terms of dissolved oxygen, biochemical oxygen demand, total nitrogen, and fecal coliform, which can be associated mainly with the contamination source from pig-breeding farms.

A review of the use of red mud as adsorbent for the removal of toxic pollutants from water and wastewater.

Red mud (an aluminium industry waste) has received wide attention as an effective adsorbent for water pollution control, showing significant adsorption potential for the removal of various aquatic pollutants. In this review, an extensive list of red-mud-based adsorbents has been compiled and their adsorption capacities (maximum uptake value of the adsorbent for the pollutant or adsorbate being removed) for various aquatic pollutants (metal ions, dyes, phenolic compounds, inorganic anions) are presented. The review provides a summary of recent information obtained using batch studies and deals with the adsorption mechanisms involved. It is evident from the literature survey that red mud has been found to be efficient for the removal of various aquatic pollutants, especially arsenic and phosphate. However, there is still a need to investigate the practical utility of these adsorbents on a commercial scale.

Application of the Nernst-Planck approach to lead ion exchange in Ca-loaded Pelvetia canaliculata.

Ca-loaded Pelvetia canaliculata biomass was used to remove Pb(2+) in aqueous solution from batch and continuous systems. The physicochemical characterization of algae Pelvetia particles by potentiometric titration and FTIR analysis has shown a gel structure with two major binding groups - carboxylic (2.8 mmol g(-1)) and hydroxyl (0.8 mmol g(-1)), with an affinity constant distribution for hydrogen ions well described by a Quasi-Gaussian distribution. Equilibrium adsorption (pH 3 and 5) and desorption (eluents: HNO(3) and CaCl(2)) experiments were performed, showing that the biosorption mechanism was attributed to ion exchange among calcium, lead and hydrogen ions with stoichiometry 1:1 (Ca:Pb) and 1:2 (Ca:H and Pb:H). The uptake capacity of lead ions decreased with pH, suggesting that there is a competition between H(+) and Pb(2+) for the same binding sites. A mass action law for the ternary mixture was able to predict the equilibrium data, with the selectivity constants alpha(Ca)(H)=9+/-1 and alpha(Ca)(Pb)=44+/-5, revealing a higher affinity of the biomass towards lead ions. Adsorption (initial solution pH 4.5 and 2.5) and desorption (0.3M HNO(3)) kinetics were performed in batch and continuous systems. A mass transfer model using the Nernst-Planck approximation for the ionic flux of each counter-ion was used for the prediction of the ions profiles in batch systems and packed bed columns. The intraparticle effective diffusion constants were determined as 3.73x10(-7)cm(2)s(-1) for H(+), 7.56x10(-8)cm(2)s(-1) for Pb(2+) and 6.37x10(-8)cm(2)s(-1) for Ca(2+).

Coconut-based biosorbents for water treatment--a review of the recent literature.

Biosorption is an emerging technique for water treatment utilizing abundantly available biomaterials (especially agricultural wastes). Among several agricultural wastes studied as biosorbents for water treatment, coconut has been of great importance as various parts of this tree (e.g. coir, shell, etc.) have been extensively studied as biosorbents for the removal of diverse type of pollutants from water. Coconut-based agricultural wastes have gained wide attention as effective biosorbents due to low-cost and significant adsorption potential for the removal of various aquatic pollutants. In this review, an extensive list of coconut-based biosorbents from vast literature has been compiled and their adsorption capacities for various aquatic pollutants as available in the literature are presented. Available abundantly, high biosorption capacity, cost-effectiveness and renewability are the important factors making these materials as economical alternatives for water treatment and waste remediation. This paper presents a state of the art review of coconut-based biosorbents used for water pollution control, highlighting and discussing key advancement on the preparation of novel adsorbents utilizing coconut wastes, its major challenges together with the future prospective. It is evident from the literature survey that coconut-based biosorbents have shown good potential for the removal of various aquatic pollutants. However, still there is a need to find out the practical utility of such developed adsorbents on commercial scale, leading to the superior improvement of pollution control and environmental preservation.

Copper removal by algal biomass: biosorbents characterization and equilibrium modelling.

The general principles of Cu(II) binding to algal waste from agar extraction, composite material and algae Gelidium, and different modelling approaches, are discussed. FTIR analyses provided a detailed description of the possible binding groups present in the biosorbents, as carboxylic groups (D-glucuronic and pyruvic acids), hydroxyl groups (cellulose, agar and floridean starch) and sulfonate groups (sulphated galactans). Potentiometric acid-base titrations showed a heterogeneous distribution of two major binding groups, carboxyl and hydroxyl, following the quasi-Gaussian affinity constant distribution suggested by Sips, which permitted to estimate the maximum amount of acid functional groups (0.36, 0.25 and 0.1 mmol g(-1)) and proton binding parameters (pK(H)=5.0, 5.3 and 4.4; m(H)=0.43, 0.37, 0.33), respectively for algae Gelidium, algal waste and composite material. A non-ideal, semi-empirical, thermodynamically consistent (NICCA) isotherm fitted better the experimental ion binding data for different pH values and copper concentrations, considering only the acid functional groups, than the discrete model. Values of pK(M) (3.2; 3.6 and 3.3), n(M) (0.98, 0.91, 1.0) and p (0.67, 0.53 and 0.43) were obtained, respectively for algae Gelidium, algal waste and composite material. NICCA model reflects the complex macromolecular systems that take part in biosorption considering the heterogeneity of the biosorbent, the competition between protons and metals ions to the binding sites and the stoichiometry for different ions.

Copper removal by algae Gelidium, agar extraction algal waste and granulated algal waste: kinetics and equilibrium.

Biosorption of copper ions by an industrial algal waste, from agar extraction industry has been studied in a batch system. This biosorbent was compared with the algae Gelidium itself, which is the raw material for agar extraction, and the industrial waste immobilized with polyacrylonitrile (composite material). The effects of contact time, pH, ionic strength (IS) and temperature on the biosorption process have been studied. Equilibrium data follow both Langmuir and Langmuir-Freundlich models. The parameters of Langmuir equilibrium model were: q(max)=33.0mgg(-1), K(L)=0.015mgl(-1); q(max)=16.7mgg(-1), K(L)=0.028mgl(-1) and q(max)=10.3mgg(-1), K(L)=0.160mgl(-1) respectively for Gelidium, algal waste and composite material at pH=5.3, T=20 degrees C and IS=0.001M. Increasing the pH, the number of deprotonated active sites increases and so the uptake capacity of copper ions. In the case of high ionic strengths, the contribution of the electrostatic component to the overall binding decreases, and so the uptake capacity. The temperature has little influence on the uptake capacity principally for low equilibrium copper concentrations. Changes in standard enthalpy, Gibbs energy and entropy during biosorption were determined. Kinetic data at different solution pH (3, 4 and 5.3) were fitted to pseudo-first-order and pseudo-second-order models. The adsorptive behaviour of biosorbent particles was modelled using a batch reactor mass transfer kinetic model, which successfully predicts Cu(II) concentration profiles.

Effect of Cu(II), Cd(II) and Zn(II) on Pb(II) biosorption by algae Gelidium-derived materials.

Biosorption of Pb(II), Cu(II), Cd(II) and Zn(II) from binary metal solutions onto the algae Gelidium sesquipedale, an algal industrial waste and a waste-based composite material was investigated at pH 5.3, in a batch system. Binary Pb(II)/Cu(II), Pb(II)/Cd(II) and Pb(II)/Zn(II) solutions have been tested. For the same equilibrium concentrations of both metal ions (1 mmol l(-1)), approximately 66, 85 and 86% of the total uptake capacity of the biosorbents is taken by lead ions in the systems Pb(II)/Cu(II), Pb(II)/Cd(II) and Pb(II)/Zn(II), respectively. Two-metal results were fitted to a discrete and a continuous model, showing the inhibition of the primary metal biosorption by the co-cation. The model parameters suggest that Cd(II) and Zn(II) have the same decreasing effect on the Pb(II) uptake capacity. The uptake of Pb(II) was highly sensitive to the presence of Cu(II). From the discrete model it was possible to obtain the Langmuir affinity constant for Pb(II) biosorption. The presence of the co-cations decreases the apparent affinity of Pb(II). The experimental results were successfully fitted by the continuous model, at different pH values, for each biosorbent. The following sequence for the equilibrium affinity constants was found: Pb>Cu>Cd approximately Zn.

Biosorption of copper by marine algae Gelidium and algal composite material in a packed bed column.

Marine algae Gelidium and algal composite material were investigated for the continuous removal of Cu(II) from aqueous solution in a packed bed column. The biosorption behaviour was studied during one sorption-desorption cycle of Cu(II) in the flow through column fed with 50 and 25 mg l(-1) of Cu(II) in aqueous solution, at pH 5.3, leading to a maximum uptake capacity of approximately 13 and 3 mg g(-1), respectively, for algae Gelidium and composite material. The breakthrough time decreases as the inlet copper concentration increases, for the same flow rate. The pH of the effluent decreases over the breakthrough time of copper ions, which indicates that ion exchange is one of the mechanisms involved in the biosorption process. Temperature has little influence on the metal uptake capacity and the increase of the ionic strength reduces the sorption capacity, decreasing the breakthrough time. Desorption using 0.1M HNO(3) solution was 100% effective. After two consecutive sorption-desorption cycles no changes in the uptake capacity of the composite material were observed. A mass transfer model including film and intraparticle resistances, and the equilibrium relationship, for adsorption and desorption, was successfully applied for the simulation of the biosorption column performance.