Presence Of Cadmium Ions Research Articles

Comparative analysis of three immunochromatographic test strips for rapid detection of cadmium ion in Asparagus

SummaryCurrently, there is increasing concern regarding the presence of cadmium ion (Cd2+) residues in Asparagus, necessitating the development of a rapid, sensitive and effective detection method. Immunochromatographic detection techniques offer a swift and efficient primary screening approach, significantly reducing labour and material resources compared to traditional detection methods. In this study, we aimed to construct and optimise an immunochromatographic test strip method for precise determination of Cd2+ content in Asparagus. To achieve this, monoclonal cadmium antibody (4A9) was prepared and conjugated with colloidal gold nanoparticles (AuNPs), latex microspheres (LM) and polydopamine (PDA) to create immunoprobes for test strip construction. We optimised key factors, such as probe parameters, strip assembly conditions and sample pretreatment methods. The sensitivity and detection capabilities of the three test strips were evaluated using actual Asparagus samples. The results demonstrated that all three immunochromatographic test strips exhibited high sensitivity, efficiency and rapidity in detecting Cd2+ levels in Asparagus. Notably, the LM‐based and PDA‐based test strips showed outstanding performance, with a visual limit of detection (vLOD) of 0.1 ng mL−1 and an elimination value of 2.0 ng mL−1. These findings underscore the promising potential of these test strips for practical cadmium detection in Asparagus samples.

Exploration of the Interaction of Cadmium and Aptamer by Molecular Simulation and Development of Sensitive Capillary Zone Electrophoresis-Based Aptasensor

The presence of cadmium ions (Cd2+) in environmental samples demands a fast, sensitive, and selective analytical method that can measure toxic levels. Biosensors based on aptamers (aptasensors) have been developed, but some of them suffer from poor sensitivity and specificity due to the immobilization of aptamers. Here, we employed circular dichroism, molecular docking, and molecular dynamics simulation to reveal that the aptamer gradually undergoes significant conformational changes upon Cd2+ binding. This fact highlights the advantages of biosensors based on free aptamers. So, keeping these results, an analytical method was established for the detection of Cd2+ by utilizing capillary zone electrophoresis (CZE), which is adapted for the free aptamer. So, CZE equipped with aptamer as a detection probe can detect Cd2+ within 4 min in the range from 5 to 250 nM with R2 = 0.994, limit of detection 5 nM (signal-to-noise ratio = 3), and recovery from 92.6 ± 1.6 to 107.4 ± 1.0% in river water samples. Furthermore, the detected concentration in water samples is below the harmful levels (267 nM) recommended by World Health Organization standards in drinking water. This method displays a high sensitivity and specificity for Cd2+. It is found to be superior to existing methods, which use immobilized aptamers, and can be readily expanded to design aptasensors for other targets.

Correlation of micro-structure with the opto-electronic properties of the sol-gel derived powder Sn1-xCdxO2 nanoparticles

Powdered cadmium substituted tin oxide (Sn1-xCdxO2) nanoparticles (NPs) with various Cd2+ ion concentrations (0%–30%) were synthesized via sol-gel route. The X-ray diffraction (XRD) and high resolution transmission electron microscopic (HRTEM) results justified the nanocrystallinity of the samples as the mean crystallite sizes were found within 16 nm–38 nm. The Williamson – Hall (W – H) analysis was employed for determining the relation between the lattice strain and crystallite size of the powder NPs. The monotonous decrease of lattice strain is consistent with the increase of crystallite size by increase in Cd2+ substitution concentration. The substitution of Sn4+ with Cd2+ caused an increase of particle size with the increase of Cd2+ concentration. The energy dispersive X-ray spectroscopic (EDS) studies indicated the presence of cadmium ion in the Cd-substituted SnO2 powder NPs. Further, the Fourier-transform infrared (FT-IR) spectra of the powder samples registered the distinct absorbance band dips highlighting the atomic vibrations. The optical absorption (OA) spectra revealed that the band gap energies (Eg) decreased with the increase in Cd2+ substitution levels. The positron annihilation lifetime (PAL) spectroscopic analysis based on the vacancy type defects which were present in abundance in the powder NPs and played vital roles to modify their properties. The photo-induced luminescence properties were studied by fluorescence (FL) spectroscopy based on defects and/or oxygen vacancies associated with the emission transitions. The results suggested the feasibility of tailoring the characteristics of Cd-substituted SnO2 NPs synthesized through sol-gel route for various technological applications.

The modulation effect of auxiliary ligands on photochromic properties of 3D naphthalene diimide coordination polymers.

Two novel naphthalene diimide (NDI) coordination polymers (CPs), [Cd(NicNDI)(4,4'-SBC)] (1) and [Cd(NicNDI)(2,2'-BPC)] (2) (NicNDI = (3-pyridylacylamino)-1,4,5,8-naphthalene diimide, 4,4'-SBC = 4,4'-stilbene dicarboxylic acid, 2,2'-BPC = 2,2'-biphenyl dicarboxylic acid), were designed and prepared by the combination of electron-deficient NicNDI and electron-rich aromatic carboxylic acid ligands in the presence of cadmium ions. The usage of aromatic carboxylic acid ligands with different conjugation degrees, sizes, shapes and charge densities leads to the generation of distinct interpenetrated three-dimensional (3D) frameworks. Interestingly, photochromism of 1 and weak photoactivity of 2 should be attributed to the introduction of different auxiliary ligands and consequently the formation of distinct interfacial contacts of electron donors (EDs)/electron acceptors (EAs) (dπ-π = 3.427 Å, infinite -ED-EA-ED-EA- for 1vs. dπ-π = 3.634 Å, discrete ED-EA-ED for 2), suggesting a subtle modulating effect of auxiliary ligands on interfacial contacts, photoinduced intermolecular electron transfer (PIET) and photoresponsive behaviors.

Novel Hydrazone Chromophore Sensor for Metallochromic Determination of Cadmium Ions

For the detection of Cd(II) in aquatic media, a novel dicyanomethylene dihydrofuran hydrazone(DCDHFH)-based colorimetric chemosensor was developed. DCDHFH was prepared by an azo-coupling process involving the diazonium chloride of 2, 4-dichloroaniline and a dicyanomethylene dihydrofuran heterocyclic moiety bearing an active methyl group. The DCDHFH chromophore showed strong solvatochromism depending on solvent polarity due to electronic delocalization. The pH sensory effects of the DCDHFH chromophore were also explored. DCDHFH could be used to identify Cd(II) in the presence of other competitive metals, as indicated by variations in color and absorbance spectra. In the presence of cadmium ions, the synthesized DCDHFH probe with hydrazone recognition moiety exhibited a significant sensitivity and selectivity to cadmium ions at the ppm concentration level (10–250 ppm). A DCDHFH-immobilized paper test strip was also prepared and effectively used for the detection of cadmium in aqueous media at various concentrations. According to CIE Lab’s criteria, colorimetric strength (K/S), and the UV–Vis absorbance spectra, the cadmium detection abilities of the DCDHFH-immobilized paper strips were evaluated. The optimal pH range for the determination of Cd(II) was monitored in the area of 5.5–6.3, with a fast chromogenic change from yellow to red relying on the Cd(II) concentration. The deposition of dicyanomethylene dihydrofuran hydrazone onto the paper strip’s surface was studied by scanning electron microscopy (SEM).

Equilibrium and Kinetic Analysis on Cadmium Ion Sequestration from Aqueous Environment by Impregnated Chicken Feather Alkaline Biosorbent

The presence of cadmium ions in the environment is dangerous to a human being because of its chronic and acute health syndromes such as hypertension, testicular atrophy, and skeletal fetus malformation. To eliminate cadmium ions from the environment, cheap, non-toxic, and environmental-friendly biosorbents, an alkaline impregnated adsorbent, were prepared in this study. Alkaline impregnated chicken feather biosorbents (AICFB) were synthesized and characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis. The AICFB prepared was employed for the cadmium sequestration from simulated wastewater. AICFB quantity, cadmium ion concentration, and temperature are parameters with significant effects on the metal ion sequestration process. Models by Langmuir, Freundlich, and Redlich-Peterson were assigned to analyse the adsorption isotherms. Experimental data seem good with all tested models, and best with the Redlich-Peterson model. The maximum sorption capacity of AICFB toward cadmium ion was 122.07 mg/g as monolayer entrapment at pH 6.5, 0.1 g of AICFB, 120 minutes contact time, and 298 K. The linear pseudo-first-order and pseudo-second-order kinetic models were applied for the analysis of kinetic data. The pseudo-second-order model suitably describes the cadmium ion uptake by AICFB, indicating the chemisorption process. The prepared AICFB demonstrates efficient cadmium metal sequestration from aqueous environments.

Removal of cadmium(II) ions using Saccharomyces cerevisiae and Leuconostoc mesenteroides immobilized in silica materials by two processing methods

Two processing methods for preparation of microbial biomass-silica biosorbent to remove cadmium ions from aqueous solution were developed. The first method involved a slow addition of sulphuric acid into previously prepared dispersion of viable Saccharomyces cerevisiae or Leuconostoc mesenteroides biomass in sodium silicate solution. The obtained material was mesoporous with irregular shape and size between 1 and 10 μm. The second method for the immobilization of microbial biomass by silica gel entrapment was developed in order to restrict desorption of microbial cells and to obtain larger particles with uniform size. The obtained particles were spherical with average particle size of 1.5 mm. Both materials with viable L. mesenteroides cells displayed higher removal efficiency compared the efficiency of materials that containing viable S. cerevisiae cells. Infrared spectra revealed an intensive secretion of dextran by Leuconostoc mesenteoides cells in the presence of cadmium ions. EDS maps clearly showed the dispersion of cadmium in the cross-section of microbial biomass-silica biosorbent. The maximum theoretical binding adsorption capacity for the silica-alginate-S. cerevisiae composite was 54 mg/g. The adsorption capacity for the silica-alginate-L. mesenteroides composite obtained after 24 cycles was about 93 mg/g. The extracellular secretion of dextran by L. mesenteroides cells immobilized in silica-alginate composite enabled efficient removal of cadmium ions. The efficiency of Cd(II) removal by microbial composite was not affected by the presence of co-existing ions at initial cadmium concentration of 1 and 4 mmol/L.

Ranking of cadmium low amount measurement systems according to economic, environmental, and functional indicators using ELECTRE analytical method

Cadmium is one of the transition metals, known by the scientific name Cd. One of its main characteristics is the high toxicity, even in very little amounts. Cadmium is often released through industrial effluents, pesticides, chemical fertilizers, and the burning of fossil fuels. Since the presence of cadmium ions in the living organisms’ body, especially humans, can cause serious damage to the liver and pancreas, and also because its role in causing cancer has been proven, measuring very low amounts of this metal is of high importance. In the first step, this study has reviewed and analyzed common laboratory methods for measuring small amounts of cadmium. Then, according to economic, environmental, feasibility, speed, and accuracy factors, all available methods were evaluated using the ELECTRE technique. The results showed that the extraction methods using Dowex Optipore V-493 resin and extraction system in Triton X-114 surfactant, placed in the first and second positions.

The effect of cadmium and growth regulator «epin-extra» on rice plants (Оryza Sativa L.) growth and biomass accumulation

Cadmium is a highly toxic metal. Under certain conditions, cadmium ions, having great mobility in soils, easily pass into plants, accumulate in them and then enter the body of animals and humans. Anthropogenic sources of cadmium entering the environment are industrial complexes producing or using cadmium, as well as thermal power plants and mineral fertilizers. The cadmium that entered the soil is mainly present in it in a mobile form, which has negative ecological significance.Various strategies are being developed to reduce the toxic effects of cadmium. The use of growth regulators can also affect the phytotoxic effects of cadmium. The aim of this work was to study the effect of the growth of the regulator “Epin-extra” under the action of cadmium on rice plants. The effect of cadmium and the growth of the regulator “Epin-extra” on the growth and biomass of aboveground organs and roots of different varieties of rice in the presence of cadmium ions in the substrate was studied. Variants without cadmium with the use of “Epin-extra” for seed soaking (“Epin1-control”) and with the addition to the growing substrate (“Epin2-control”) served as a control.The use of the growth regulator “Epin-extra” led to an increase in the growth parameters of aerial organs and roots in the absence and in the presence of cadmium ions in the growing substrate, increasing the resistance of plants. A different effect was found depending on the form of application of the growth regulator, and varietal differences were also observed, which indicates a genetic difference in plant re- sponses to the action of a toxicant and growth regulators, which is due to various complex mechanisms of the signaling system in different genotypes under stress conditions with the involvement of the hormonal system of plants.   Key words: rice, cadmium, tolerance, growth, growth regulator, “Epin-extra”.

Callusogenesis and morphogenesis in wheat culture in the presence of cadmium ions

Callusogenesis and morphogenesis in wheat culture in the presence of cadmium ions

Highly Electroconductive Metal-Organic Framework: Tunable by Metal Ion Sorption Quantity.

This study has developed a simple and innovative approach to design a metal-organic framework (MOF) with tunable conductivity. The in situ amine functionalized TMU-60 [Zn(OBA)(L*)·DMF] has the potential of converting to a conductor due to the selective and fast sorption of cadmium ion. In order to precisely monitor the cadmium penetration to the framework pores, in addition to full kinetic and thermodynamic studies of sorption, the time-dependent effects of Cd(II) penetration to MOF pores was taken by fluorescence and electrochemical methods. The results obviously prove that the conductivity of the structure can be adjusted by changing the Cd exposure time and the quantity of ion sorption. The presence of cadmium ions can enhance the ability of the framework to pass electrons through its constituents. Even though the porosity of the structure remains to a certain extent, the achieved tunable and highly stable electrical conductivity is provided by sorption of metal ions. More importantly, the conductivity has been improved from 53 × 10-6 to 1.8 × 10-2 S·cm-1 for TMU-60 and TMU-60-Cd compressed pellet (room temperature), respectively. The mechanism of charge transport through the pellet is proposed to be a hopping mechanism between metal nodes and localized Cd(II) after sorption, which is supported by chronoamperometry measurement. A fit of the time-dependent data to the Cottrell equation gave a charge-transport diffusion coefficient of 1.6 × 10-10 cm2/s throughout the structure. This novel approach not only enhances the conductivity of the MOF but also allows adjusting the conductivity according to the desired applications.

Solvent-Free Synthesis of Phosphonic Graphene Derivative and Its Application in Mercury Ions Adsorption.

Functionalized graphene was efficiently prepared through ball-milling of graphite in the presence of dry ice. In this way, oxygen functional groups were introduced into material. The material was further chemically functionalized to produce graphene derivative with phosphonic groups. The obtained materials were characterized by spectroscopic and microscopic methods, along with thermogravimetric analysis. The newly developed material was used as an efficient mercury adsorbent, showing high adsorption efficiency. The adsorption isotherms were fitted using Freundlich and Langmuir models. The adsorption kinetics were fitted with pseudo-first order and pseudo-second order models. Adsorption selectivity was determined in the presence of cadmium ions and nickel ions. The presence of mentioned bivalent ions in the solution did not affect mercury adsorption efficiency.

Metal complexation by histidine-rich peptides confers protective roles against cadmium stress in Escherichia coli as revealed by proteomics analysis.

The underlying mechanism and cellular responses of bacteria against toxic cadmium ions is still not fully understood. Herein, Escherichia coli TG1 expressing hexahistidine-green fluorescent protein (His6GFP) and cells expressing polyhistidine-fused to the outer membrane protein A (His-OmpA) were applied as models to investigate roles of cytoplasmic metal complexation and metal chelation at the surface membrane, respectively, upon exposure to cadmium stress. Two-dimensional gel electrophoresis (2-DE) and two-dimensional difference in gel electrophoresis (2D-DIGE) in conjunction with mass spectrometry-based protein identification had successfully revealed the low level expression of antioxidative enzymes and stress-responsive proteins such as manganese-superoxide dismutase (MnSOD; +1.65 fold), alkyl hydroperoxide reductase subunit C (AhpC; +1.03 fold) and DNA starvation/stationary phase protection protein (Dps; −1.02 fold) in cells expressing His6GFP in the presence of 0.2 mM cadmium ions. By contrarily, cadmium exposure led to the up-regulation of MnSOD of up to +7.20 and +3.08 fold in TG1-carrying pUC19 control plasmid and TG1 expressing native GFP, respectively, for defensive purposes against Cd-induced oxidative cell damage. Our findings strongly support the idea that complex formation between cadmium ions and His6GFP could prevent reactive oxygen species (ROS) caused by interaction between Cd2+ and electron transport chain. This coincided with the evidence that cells expressing His6GFP could maintain their growth pattern in a similar fashion as that of the control cells even in the presence of harmful cadmium. Interestingly, overexpression of either OmpA or His-OmpA in E. coli cells has also been proven to confer protection against cadmium toxicity as comparable to that observed in cells expressing His6GFP. Blockage of metal uptake as a consequence of anchored polyhistidine residues on surface membrane limited certain amount of cadmium ions in which some portion could pass through and exert their toxic effects to cells as observed by the increased expression of MnSOD of up to +9.91 and +3.31 fold in case of TG1 expressing only OmpA and His-OmpA, respectively. Plausible mechanisms of cellular responses and protein mapping in the presence of cadmium ions were discussed. Taken together, we propose that the intracellular complexation of cadmium ions by metal-binding regions provides more efficiency to cope with cadmium stress than the blockage of metal uptake at the surface membrane. Such findings provide insights into the molecular mechanism and cellular adaptation against cadmium toxicity in bacteria.

Heavy Metal-Induced Expression of PcaA Provides Cadmium Tolerance to Aspergillus fumigatus and Supports Its Virulence in the Galleria mellonella Model.

Most of the metal transporters in Aspergillus fumigatus are yet uncharacterized. Their role in fungal metabolism and virulence remains unclear. This paper describes the novel PIB-type cation ATPase PcaA, which links metal homeostasis and heavy metal tolerance in the opportunistic human pathogen A. fumigatus. The protein possesses conserved ATPase motif and shares 51% amino acid sequence identity with the Saccharomyces cerevisiae cadmium exporter Pca1p. A pcaA deletion, an overexpression and a gfp-pcaA complementation strain of A. fumigatus were constructed and their heavy metal susceptibilities were studied. The pcaA knock out strain showed drastically decreased cadmium tolerance, however, its growth was not affected by the exposure to high concentrations of copper, iron, zinc, or silver ions. Although the lack of PcaA had no effect on copper adaption, we demonstrated that not only cadmium but also copper ions are able to induce the transcription of pcaA in A. fumigatus wild type Af293. Similarly, cadmium and copper ions could induce the copper exporting ATPase crpA. These data imply a general response on the transcriptomic level to heavy metals in A. fumigatus through the induction of detoxification systems. Confocal microscopy of the gfp-pcaA complementation strain expressing functional GFP-PcaA supports the predicted membrane localization of PcaA. The GFP-PcaA fusion protein is located in the plasma membrane of A. fumigatus in the presence of cadmium ions. Virulence assays support a function of PcaA for virulence of A. fumigatus in the Galleria mellonella wax moth larvae model, which might be linked to the elimination of reactive oxygen species.

Wpływ kwasów organicznych na fitotoksyczność oraz akumulację kadmu przez rośliny słonecznika

The paper presents results of a study on the impact of low molecular organic acids on phytotoxicity and efficiency of cadmium uptake and translocation by sunflower plants (Helianthus annuus L.). The cadmium-contaminated substrate (100 mg Cd · kg–1) was treated with solutions of citric or oxalic acid at concentrations of 25 or 50 mmol · dm–3. It was found that the presence of cadmium ions in the substrate caused a slight reduction in the biomass of shoots, but their elongation growth was strongly limited. There was no significant effect of the applied cadmium dose on the content of photosynthetic pigments in the leaves. Application of organic acids to the contaminated substrate did not usually  have a negative effect the growth of plants and the level of photosynthetic pigments, but resulted in a significant reduction of cadmium content in shoots, especially under the influence of a higher dose of acids used. It was shown that oxalic acid was more effective in reducing the translocation of cadmium to the aboveground parts of sunflower than citric acid.

Facile synthesis of ternary TiO2 NP/Rh & Sb-codoped TiO2 NR/titanate NT composites photocatalyst: Simultaneous removals of Cd2+ ions and Orange (II) dye under visible light irradiation (λ ≥ 420 nm)

In this study, rhodium and antimony doped nanorod (RS-TONR) was prepared by a molten salt solid state chemical reaction, and TiO2 nanorod and titanate nanotube (RS-TONR/TiNT) composite photocatalyst was synthesized by a hydrothermal method for different reaction times. The structural and chemical analyses of nanomaterials were performed by FE-SEM, XRD, UV-DRS and surface BET characterizations. The XRD and HR-TEM data confirmed that the as-synthesized material had mixed phase of TiO2 nanorod and Titanate nanotube (RS-TONR/TiNT). The photocatalytic activity of the composite photocatalyst was observed over the degradation of Orange (II) dye under visible light irradiation. Acid treatment and copper loading was conducted to enhance the surface property of RS-TONR/TiNT sample. The formation of TiO2 nanoparticle with anatase phase was observed by TEM and XRD analysis. The TEM mapping data also confirmed that copper oxide nanoparticles were well dispersed on the surface of titanate nanotubes. These dispersed nanoparticles were observed by XPS and STEM characterizations. The higher removal efficiency of Cd2+ ions was observed over the acid treated and untreated Cu3-TNP/TiNT/RS-TONR in the presence of Orange (II) dye. A higher photocatalytic activity of acid treated and Cu3-TNP/TiNT/RS-TONR was simultaneously obtained in the presence of cadmium ions during the degradation of Orange (II) dye.

Photophysical and ion-binding studies of a tetranuclear alkynylgold(I) isonitrile complex

A number of polyamide-containing multinuclear alkynylgold(I) isonitrile complexes have been designed, synthesized and characterized. The tetranuclear gold(I) complex is found to show spectroscopic responses in the presence of cadmium ions. The photophysical properties of the complex can be modulated via the suppression of photo-induced electron transfer (PET) and intramolecular Au⋯Au interactions. The binding mode of the complex has also been investigated by 1H NMR spectroscopy. The complex is found to be highly selective towards cadmium ions as well as zinc ions.

The Activity of Cell-Wall Modifying β-1,3-Glucanases in Soybean Grown in Presence of Heavy Metals

AbstractCell walls represent the first barrier that can prevent the entrance of toxic heavy metals into plants. The composition and the flexibility of the cell wall are regulated by different enzymes. The ß-1,3-glucanases control the degradation of the polysaccharide callose as a flexible regulation mechanism of cell wall permeability and/or its ability to bind metals under stress conditions. The profile and activity of ß-1,3-glucanases in the presence of heavy metals, however, has rarely been studied. Here we studied these enzymes in four soybean varieties (Glycine max) grown in the presence of cadmium ions. These analyses revealed three acidic and one basic enzyme isoforms in each soybean variety, but only two of the acidic isoforms in the variety Moravians were substantially responsive to the presence of Cd2+. Since the responses of certain glucanases were detected mainly in the varieties sensitive to metal and accumulating high amounts of metals, we assume their role in the defense rather than strategic metal sequestration.

Improved ethanol production in the presence of cadmium ions by a Saccharomyces cerevisiae transformed with a novel cadmium-resistance gene DvCRP1

ABSTRACTThe DvCRP1 gene obtained from Dunaliella viridis is a cadmium-resistance gene that induces cadmium accumulation in microbial and plant cells. In the present study, Saccharomyces cerevisiae was used as a model system to investigate the effect of DvCRP1 on both cadmium detoxification and ethanol production. Inhibitory effects of cadmium (50–300 µmol/L) on growth (29–92%), glucose consumption (23–89%), and ethanol production (17–92%) were observed at 24 h by S. cerevisiae. DvCRP1 alleviated the inhibitory effect of cadmium, with increase in the ethanol production. The established mathematical model showed that the initial inoculation concentration, cadmium concentration, and transformation of DvCRP1 were the most important factors for cell growth, glucose consumption, and ethanol production. Cadmium detoxification of yeast was also enhanced by increasing the initial concentration of yeast cells. Transforming with DvCRP1 further enhanced detoxification, especially at high cadmium concentrations. Transforming with DvCRP1 further enhanced detoxification, especially at high cadmium concentrations (200 µmol/L). The present results evidenced the potential of the insertion of the DvCRP1 gene into yeast for use in bio-refineries during fermentation of heavy metals-contaminated substrates. In addition, this is a promising method for phytoremediation of agricultural soils highly contaminated by heavy metals.

A novel modification and selective route for the adsorption of Pb2+ by oak charcoal functionalized with glutaraldehyde

Oak activated carbon was modified and used for the removal of lead ions from water. A new modification route was performed using glutaraldehyde as the active complexing ligand. The fictionalization was done through a two step modification route. The particle size distribution was determined by Granulometric analysis and the functional groups were identified by FT-IR spectroscopy. This modification method was found to be very efficient for lead adsorption. The effects of contact time, pH and initial lead concentration were investigated. The experimental kinetic data were well fitted by the pseudo-second order kinetic model and Langmuir isotherm with a maximum adsorption capacity up to 137mgg−1. The selectivity for lead ions was examined as well in the presence of cadmium ions. The mechanism of lead removal by the modified carbon was also studied.