Removal of toxic metals from aqueous mixtures. Part 1: Biosorption

The biosorption of toxic metals from an aqueous mixture containing zinc, copper and nickel, in the presence of calcium and sodium ions (usual co‐existing cations in related systems) has been investigated. Industrial biomass samples of different origin have been examined batchwise as effective sorbents, including bacteria (Streptomyces rimosus), fungi (Penicillium chrysogenum) and yeasts (Saccharomyces carlsbergensis and Saccharomyces cerevisiae). The effect of solution pH was evaluated in the range of 3–11.5. Selectivity was observed, particularly for the removal of copper. The observed removal of metals by the application of biosorption was also compared in laboratory experiments with other more conventional separation techniques (filtration, centrifugation and flotation). © 1999 Society of Chemical Industry     

The interaction between Cu,Pb, Zn and Ni in their biosorption onto polyurethane‐immobilised Sphagnum moss

The uptake of Cu(II), Pb(II), Zn(II) and Ni(II) was investigated both individually and from mixed metal ion solutions using Sphagnum moss biomass immobilised in a polyurethane support. The data were evaluated using the Langmuir isotherm equation, and sorption capacities were calculated for different concentration ranges. It was concluded that care must be taken in presentation and interpretation of results when this modelling approach is applied at low concentrations. Repeated metal loading cycles also gave lower values for sorption capacity compared with the maximum potential value, due to equilibrium effects. The uptake capacity for the different metals on a weight basis was in the order lead > copper > zinc > nickel, but on a molar basis this changed to copper > lead > nickel > zinc. Sorption from a multi‐component metal system showed that lead and copper competed equally for binding sites and much more effectively than zinc and nickel. Equations were derived to predict the percentage effect on a given metal ion of other metals in a multi‐metal system based their behaviour in the relevant single and binary systems. Copyright © 2005 Society of Chemical Industry     

Treatment of wastewater containing copper,zinc, nickel and cobalt using Duolite ES‐467

Duolite ES‐467 was used to treat wastewater containing heavy metal ions. Sorption experiments were carried out at varying pH values, agitation speeds, reaction times, and metal ion and sorbent concentrations. Each of the parameters affects the sorption behaviour of individual metal ions. Copper sorption was greater compared with other metal ions such as zinc, nickel and cobalt. The presence of other metal ions affects copper sorption. Equilibrium isotherm curves were developed. These were used to predict that the metal ion concentration would be reduced from 100 to less than 1 mg dm^?3. Fixed bed tests were conducted to investigate the efficiency of Duolite ES‐467 for the selective removal of copper ions from multi‐metal solutions. Breakthrough curves were obtained using Duolite ES‐467 for solutions containing copper, nickel and copper, zinc, nickel and cobalt. Elution studies were also carried out using sulfuric acid. © 2002 Society of Chemical Industry     

Determination of Copper,Iron, Nickel,and Zinc in Ethanol Fuel by Flame Atomic Absorption Spectrometry Using On‐Line Preconcentration System

Abstract

In this work, an on‐line system for preconcentration and determination of copper, iron, nickel, and zinc at µg L^?1 level by flame atomic absorption spectrometry (FAAS) has been developed. Amberlite XAD‐4 functionalized with 3,4‐dihydroxybenzoic acid packed in a minicolumn was used as metal sorbent. The retained metals can be quickly eluted from sorbent material, with the eluent stream consisting of hydrochloric acid solution, directly to the nebulizer burner system of the FAAS. Analytical parameters were evaluated and the results demonstrated that all studied metals can be determined, using borate buffer to adjust the sample pH at 8.0. The results showed that the proposed method is simple and rapid. The limits of detection were estimated as 2.3, 5.0, 7.8, and 0.1 µg L^?1 for copper, iron, nickel, and zinc, respectively, using a preconcentration time of 60 s and a sample flow rate of 5.5 mL min^?1. Enrichment factors of 22, 15, 12, and 54 and coefficients of variations of 3.5, 4.4, 4.4, and 3.2% were obtained in the determination of copper, iron, nickel, and zinc, respectively. The system presented an analytical throughput of 10 samples per hour and was successfully applied in the determination of metals in ethanol fuel.     

Nickel and copper removal from aqueous solution by an immature coal (leonardite): effect of pH,contact time and water hardness

The removal of Ni(II) and Cu(II) from aqueous solutions by a low cost sorbent (leonardite) was studied. The metal uptake was pH‐dependent and the maximum sorption for two metals was obtained at around pH 5–6. Batch kinetic studies showed that equilibrium time was reached after 2 h of contact time. Equilibrium isotherms were obtained for the adsorption data of the two metals in single and binary systems. Equilibrium data were fitted to Langmuir and Freundlich models and the maximum adsorption capacities were found to be 0.33 mmol of copper and 0.26 mmol of nickel per gram of leonardite. In binary solutions containing the two metals an important reduction of nickel uptake was observed while the sorption of copper was less affected. The presence of Ca²⁺ affected the removal of both copper and nickel ions, although the adsorption of nickel was reduced more than that of copper. Copyright © 2005 Society of Chemical Industry     

Solvent extraction with LIX 973N for the selective separation of copper and nickel

LIX 973N diluted with Iberfluid was used to co‐extract copper and nickel from ammoniacal/ammonium carbonate aqueous media. The influence of equilibration time, temperature, equilibrium pH and extractant concentration on the extraction of both metals has been studied. It was observed that neither copper nor nickel extraction is sensitive to temperature and equilibrium pH, however nickel extraction equilibrium is reached at a longer contact time (20 min) than that of copper (5 min), in addition nickel extraction depends greatly on the extractant concentration in the organic phase. For a solution containing 3 g dm⁻³ each of copper and nickel and 60 g dm⁻³ ammonium carbonate, conditions were established for the co‐extraction of both metals, ammonia scrubbing and selective stripping (with H₂SO₄) of nickel and copper. Using the appropriate extractant concentration the yield (extraction stage) for both metals is near 100%, whereas the percentage of nickel and copper stripping is also almost quantitative. © 1999 Society of Chemical Industry     

Metal ion separation and recovery from environmental sources using various flotation and sorption techniques

Flotation is a gravity separation process that originated from processing of minerals, and has nowadays found wide application, for instance, in industrial waste‐water treatment. It is also useful in the concentration of a variety of dissolved chemical species often following a sorption process. The present review paper focuses on the removal of heavy metal ions from aqueous solution. The process mechanisms involved are either sorptive flotation where metal bonding agents, including biosorbents, are added and the subsequent complexes are separated downstream by flotation or other conventional flotation techniques, such as ion flotation are used. In the laboratory experiments described in this paper, zinc has been used as an example, but in addition copper, nickel, arsenic, etc. are considered. A new hybrid flotation–microfiltration cell is also introduced. Copyright © 2010 Society of Chemical Industry     

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     

Bioremoval of Metal Ion and Water Treatment in a Hybrid Unit

Abstract

Several biomass types, such as yeast (in the present Saccharomyces, a brewery waste), have been reported to remove heavy metals (i.e., zinc) from aqueous solution. The separation of metal-loaded biomass and hence, the production of a clean water stream using a hybrid flotation-microfiltration unit were investigated. The hybrid cell consisted of a microfiltration module submerged directly into a flotation cell. Air bubbling, constituting the transport medium during flotation, meanwhile has been used in order to limit the membranes fouling. The effects of air sparging, the solid particle content, and the type and concentration of flotation reagents on the performance of the hybrid process were the main examined parameters.     

Sensing of toxic metals through pH changes using a hybrid sorbent material: Concept and experimental validation

This article reports a new hybrid sorbent material that is capable of detecting trace concentration of toxic metals, such as zinc, lead, copper, nickel, etc., through pH changes only. The material is essentially a composite granular material synthesized through rapid fusion of a mixture of amorphous hydrated ferric oxide (HFO) and akermanite or calcium magnesium silicate (Ca₂MgSi₂O₇). When a water sample is rapidly passed through a mini‐column containing this hybrid material, effluent pH at the exit always remains alkaline (≈9.0) because of slow hydrolysis of akermanite and steady release of hydroxyl (OH^?) ions. This exit solution turns pink through the addition of a phenolphthalein indicator. Commonly encountered electrolytes containing sodium, calcium, chloride, and sulfate have no impact on the exit pH from the mini‐column. However, when trace concentration of a heavy metal (say lead) is present in the sample water, a considerable drop in pH (>2 units) is observed for the exiting solution. At this point, the solution turns colorless through the addition of a phenolphthalein indicator. Moreover, the change in the slope of pH, i.e., ?dpH/dBV, provides a sharp, noticeable peak for each toxic metal where BV is the bed volumes of solution fed. The technique allowed detection of zinc and lead through pH swings in synthesized samples, spiked Bethlehem City water, and also in Lehigh River water in the presence of phosphate and natural organic matter (NOM). Using a simple preconcentration technique, lower than 10 μg/l of lead was detected with a significant peak. From a mechanistic viewpoint, high sorption affinity of HFO surface sites toward toxic metal cations, ability of akermanite to maintain near‐constant alkaline pH for a prolonged period through slow hydrolysis and labile metal‐hydroxy complex formation causing dissipation of OH^? ions from the aqueous phase provide a synergy that allows detection of toxic metals at concentrations well below 100 μg/l through pH changes. Nearly all previous investigations pertaining to toxic metals sensing use metal‐selective enzymes or organic chromophores. This simple‐to‐operate technique using an inexpensive hybrid material may find widespread applications in the developing world for rapid detection of toxic metals through pH changes. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Removal of Molybdate and Arsenate from Aqueous Solutions by Flotation

Abstract

Ion flotation and adsorbing colloid flotation have been studied in this paper for the effective removal of molybdenum(VI) and arsenic(V) from dilute aqueous solutions. These different flotation methods were also compared. Ion flotation using a cationic surfactant (dodecylamine) as collector, as well as adsorbing colloid flotation using ferric hydroxide as coprecipitant (or sorbent) and an anionic surfactant (sodium dodecyl sulfate) as collector were examined. Laboratory-scale experiments were conducted in order to assess the effects of the following parameters on the efficiency of the process: pH value, dosages of chemical reagents, initial concentrations of arsenic and molybdenum, and the presence of foreign anions, such as Cl^- and SO² ₄ ^-. In practical applications, ion flotation or adsorbing colloid flotation may be selected according to the concentration of arsenic, molybdenum, and also the initial [Mo]/[As] molar ratios in solution.     

Dissolved-Air Flotation of Metal Ions

Abstract

Metal ions (copper, nickel, zinc, and ferric ions) were separated from dilute aqueous solutions by dissolved-air flotation. The ions were either precipitated as sulfides or floated (as ions) by xanthates. Copper and nickel were selectively separated; promising results were obtained with single, binary, and ternary mixtures. The effect of several parameters (solution pH, addition of chemical reagents at varying concentrations, and the presence of other ions) on the removal of ions was studied. The collectorless flotation of copper ions was also investigated.     

Ni(ll) biosorption by Rhizopus arrhizus Env 3: the study of important parameters in biomass biosorption

BACKGROUND: The removal of toxic metals from wastewaters by biosorption, based on the metal‐binding capacities of various biological materials, has attracted much interest. However, the success of this approach depends on economic feasibility, which can be obtained by optimisation of the environmental conditions. In this study, Ni(II) biosorption experiments were carried out using a preformed biomass of Rhizopus arrhizus. A pure culture of previously isolated R. arrhizus Env 3 was used for maximum biosorption of nickel metal from nickel‐electroplating industrial effluent. RESULTS: Various environmental factors such as nickel concentration, pH, temperature, mycelial pellet weight, pretreatment of fungal biomass, dead and living fungal biomass and time course of biosorption by R. arrhizus Env 3 were optimised for maximum removal of nickel from the effluent. The maximum nickel removal rate of 618.5 mg g^?1 was observed with living biomass at pH 8, temperature 35 °C, nickel concentration 500 mg L^?1, pellet size 3 g wet weight and shaker velocity 150 rpm. Maximum nickel biosorption was obtained after 72 h. CONCLUSION: Statistical analysis of different factors such as temperature, pH, mycelial pellet size, concentration of nickel in effluent and residual nickel level showed that all these factors had significant effects on the biosorption of nickel metal by R. arrhizus Env 3 from nickel‐electroplating industrial effluent. Copyright © 2008 Society of Chemical Industry     

Liquid-liquid distribution of metals in systems with trioctylmethylammonium dinonyl naphthalenesulfonate

The extraction of copper, nickel, cobalt, zinc, and iron chlorides by the solutions of trioctylmethylammonium dinonyl naphthalenesulfonate in toluene depending on the acidity of aqueous phase was studied. In the range of relatively high acidity (from 3 to 1 M HCl), an increase in the D _M values is observed with a growth in the concentration of hydrogen ions in aqueous phase; that corresponds to the principles of the binary extraction of chloro complex metal-containing acids. With a decrease in the acidity of aqueous phase, an increase in the distribution coefficients of metals is observed due to the change in the extraction mechanism and increase in the fraction of the complexes extracted as metal dinonyl naphthalenesulfonates. In the acidic range, the extractability of metals is mainly determined by the stability of complex metal-containing anions and qualitatively corresponds to the following order: Fe(III) > Cu(II) > Co(II) > Ni(II).     

Biosorption of Naphthalene from Refinery Simulated Waste-Water on Blank Alginate Beads and Immobilized Dead Algal Cells

Abstract

The potential use of blank alginate beads and immobilized dead algal cells for the removal of naphthalene from aqueous solutions was investigated in this study. The effects of contact time, solution pH, and naphthalene concentration on the sorption of naphthalene on blank alginate beads or immobilized dead algal cells were studied. The effect of the presence of other pollutants on the sorption of naphthalene on immobilized dead algal cells was also studied.

Batch adsorption experiments showed that the removal of naphthalene on both sorbents was pH dependent and significant removal of naphthalene was obtained at pH 4. Dynamic sorption experiments revealed that the biosorption of naphthalene on either sorbent was rapid where the equilibrium uptake occurred within 10 minutes, and the biosorption of naphthalene on either sorbent followed the pseudo-second order kinetics. Analysis of the equilibrium sorption data showed that naphthalene sorption on either sorbent could be fitted to the Langmuir, Freundlich, and Dubinin-Radushkevich (D–R) isotherm equations. Competitive biosorption experiments showed that biosorption of naphthalene on immobilized dead algal cells was adversely affected by the presence of either heavy metals such as copper and nickel, and chelating agents such as citric acid.     

Biosorption of heavy metals (Cd,Cu, Ni,Pb, Zn) by chemically-reinforced biomass of marine algae

Particles of two different sizes (0·105–0·295 mm and 0·84–1.00 mm diameter) of two marine algae, Sargassum fluitans and Ascophyllum nodosum, were crosslinked with formaldehyde (FA), glutaraldehyde (GA) or embedded in polyethylene imine (PEI), followed by glutaraldehyde crosslinking. They were used for equilibrium sorption uptake studies with cadmium, copper, nickel, lead and zinc. The metal uptake by larger particles (0·84–1·00 mm) was higher than that by smaller particles (0·105–0·295 mm). The order of adsorption for S. fluitans biomass particles was Pb > Cd > Cu > Ni > Zn, for A. nodosum copper and cadmium change places. Uptakes of metals range from q_max = 378 mg Pb g^?1 for S. fluitans (FA, big particles), to q_max = 89 mg Zn g^?1 for S. fluitans (FA, small particles) as the best sorption performance for each metal. Generally, S. fluitans is a better sorbent material for a given metal, size and modification, although there were several exceptions in which metal sorption by A. nodosum was higher. The metal uptake for different chemical modifications showed the order GA > FA > PEI. A comparison of different sorption models revealed that the Langmuir sorption model fitted the experimental data best.     

A New Hybrid Flotation—Microfiltration Cell

Abstract

The investigated hybrid cell combines the advantages of both flotation and membrane separation, while overcoming their limitations and having as an outcome clean water from a industrial wastewater. Hence, metals recovery from dilute aqueous solutions was a promising application of this innovative process, further to solid/liquid separation. The specific objective was to apply the process for the efficient separation of effluents containing metals (here, zinc). The main examined parameters were the following: the metal initial concentration, flotation surfactant applied, and air flowrate. The successful contribution of precipitate flotation was highlighted, while the observed metal removals were of the order of ～100%.     

Removal of Heavy Metals from Aqueous Solutions Using Microgas Dispersions

Abstract

Flotation by means of microgas dispersions was used to remove copper, chromium, nickel, lead, and zinc from aqueous solutions, including an industrial plating effluent. Metal removals of up to 100% were obtained from solutions of the metals ranging in concentration from 2 to 20 ppm.     

Biosorptive Flotation in Metal Ions Recovery

Abstract

Heavy metals can be removed from dilute aqueous solutions in many ways. Among the innovative ones may be classified a process consisting of biosorption followed by flotation. A metal cation, cadmium, was examined; the metal was abstracted by microorganisms belonging to the Actinomycetes, i.e., Streptomyces clavuligerus and Streptomyces griseus, which have a filamentous morphology, and hence present a flocculent character. Dissolved-air flotation was the technique applied on a laboratory scale without the addition of any flotation surfactant. The parameters investigated in the batch mode were contact time, recycle ratio, solution pH, Cd concentration, biomass addition, and use of a frother (ethanol). Promising results were obtained; in certain cases an almost quantitative cadmium abstraction, followed by higher than 90% biomass recovery, was found.     

The extraction of anionic complexes of divalent manganese,cobalt, nickel and copper from aqueous thiocyanate solutions by tricaprylmethylammonium chloride

The extraction of divalent manganese, cobalt, nickel and copper-thiocyanato anionic species from aqueous solutions by tricaprylmethylammonium chloride (R₃R′NCl) in benzene has been investigated under different conditions. Both the aqueous and organic phases have been examined by spectrophotometry. Infrared spectro-photometry and measurements of water content, apparent molecular weight and magnetic moment have been applied to the organic extracts, and electron spin resonance experiments to the organic manganese(II)- and copper(II)-complexes. The mechanism of the extractions and the structures of the extracted complexes are discussed on the basis of the results obtained. As a result, it is found that although the extraction efficiency follows the order Co > Cu > Mn > Ni, the extraction of divalent transition metals is expressed as [M(NCS)₄]²-(aq) + 2R₃R′NNCS(org)→(R₃R′N)₂-[M(NCS)₄](org) + 2NCS-(aq) in which M = Mn, Co, Ni and Cu. The extracted species of divalent manganese, cobalt and nickel give a tetrahedral T_d symmetry, and the copper(II) species is in a distorted tetrahedron (point group D_2d symmetry). In addition the species of nickel (II) extracted at low aqueous concentration exists as a complex (R₃R′N)₂[Ni(NCS)₄(H₂O)₂] in an octahedral arrangement.