Adsorption Distribution Coefficients Research Articles

Phosphorus Sorption Characteristics and External Phosphorus Requirement of Bulle and Wonago Woreda, Southern Ethiopia

Determination of the P-sorption characteristics of soils is important for economic fertilizer application and to recommend appropriate management strategies for high P-fixing soils. Thus, the objectives of this study were to evaluate P-sorption characteristics of soils occurring in some areas of southern Ethiopia and identify factors contributing to P sorption. Composite surface (0-20 cm) soil samples from 6 sites of two locations were collected. The results revealed that the P-sorption data were fitted well with both Langmuir and Freundlich models with r2 values of 0.99. But later model was found to better in describing P-sorption data than the former model. The adsorption maxima (Xm) and distribution coefficient (Kf) values of soils ranged from 909-2000 mg PKg-1 and 245-487 mg PKg-1 based on Langmuir and Freundlich models respectively. The corresponding SPR values ranged between 57-196 mg P kg-1 and 71.8-211 mg P kg-1 based on Langmuir and Freundlich models respectively. Bonding energy constant (K) of Langmuir model and Freundlich constant (b) ranged from 0.15-1.4 and 0.54-0.66 Lmg-1 respectively. The bonding energy constant (K) of Langmuir model was found to be more valuable than Xm in discriminating the study soils as high and low P sorbing soils. Based on both models soils of Bulle had SPR values >150 mg PKg-1 and then were classified as high P-fixing soils while soils of Wonago had SPR values <150 mgPKg-1 were classified as low P-fixing. The result of path analysis revealed that exchangeable Al and Clay had direct effect on P-sorption parameters of both models. It is concluded that P-sorption models can effectively be used to discriminate soils based on P-fixation ability. However, validation of both models through real time experiments in greenhouse and field is recommended before the models used for large scale.

Removal and recovery of lead (Pb2+) from industrial effluent using indigenous and tailor-made Aureobasidium sp. RBSS-303.

The objective of this study was to assess the removal and recovery of Pb-II from industrial wastewater using a locally isolated strain of Aureobasidium sp. RBSS-303. The initial Pb2+ concentration of 600 mg/L resulted in maximum uptake capacity (Qmax 235.1±0.3 mg/g). The biosorbent revival was attained by contacting with HCl (0.01 M), with 75.3% recovery of Pb2+. The Freundlich isotherm best explains the Pb2+ sorption performances. Maximum adsorption distribution coefficient of 1,309.6 mg metal/mL was observed at initial Pb2+ concentration value of 100 mg/L. Evaluation of nine kinetic models showed the removal rate of Pb2+ was reliant on diffusion control pseudo-second-order and saturation-mixed-order kinetic models with a high correlation coefficient value (R=0.99). Fourier transform infrared spectroscopy analysis showed the major contribution of -NH2 and -CN ligands of Aureobasidium sp. RBSS-303 in the sorption phenomenon of Pb2+. The biosorption assays carried out with effluent of the paint industry showed 76.8% efficiency for Pb2+ removal by the candidate biosorbent, regardless of the complex composition of the industrial effluent.

Parameters describing nonequilibrium transport of polycyclic aromatic hydrocarbons through contaminated soil columns: Estimability analysis, correlation, and optimization

The soil and groundwater at former industrial sites polluted by polycyclic aromatic hydrocarbons (PAHs) produce a very challenging environmental issue. The description of PAH transport by means of mathematical models is therefore needed for risk assessment and remediation strategies at these sites. Due to the complexity of release kinetics and transport behavior of the PAHs in the aged contaminated soils, their transport is usually evaluated at the laboratory scale. Transport parameters are then estimated from the experimental data via the inverse method. To better assess the uncertainty of optimized parameters, an estimability method was applied to firstly investigate the information content of experimental data and the possible correlations among parameters in the two-site sorption model. These works were based on the concentrations of three PAHs, Acenaphthene (ACE), Fluoranthene (FLA) and Pyrene (PYR), in the leaching solutions of the experiments under saturated and unsaturated flow conditions. The estimability results showed that the experiment under unsaturated flow conditions contained more information content for estimating four transport parameters than under the saturated one. In addition, whatever the experimental conditions for all three PAHs the fraction of sites with instantaneous sorption, f, was highly correlated with the adsorption distribution coefficient, Kd. The very strong correlation between the two parameters f and Kd suggests that they should not be simultaneously calibrated. Transport parameters were optimized using HYDRUS-1D software with different scenarios based on the estimability analysis results. The optimization results were not always reliable, especially in the case of the experiment under saturated flow conditions because of its low information content. In addition, the estimation of transport parameters became very uncertain if two parameters f and Kd were optimized simultaneously. The findings of the current work can suggest some reasons behind the optimization problems and indicate the type of experimental information additionally needed for parameter identification. To overcome the parameterization issues of PAH non-equilibrium transport, the experimental design, timescale, and model refinement need further improvement. The conclusions presented in this paper are not limited necessarily to PAHs, but may also be relevant to other organic contaminants with similar leaching behavior.

Removal of uranium(VI) from aqueous solutions using nanoporous ZnO prepared with microwave-assisted combustion synthesis

The adsorption of the uranyl ions from aqueous solutions on the nanoporous ZnO powders has been investigated under different experimental conditions. The adsorption of uranyl on nanoporous ZnO powders were examined as a function of the contact times, pH of the solution, concentration of uranium(VI) and temperature. The ability of this material to remove U(VI) from aqueous solution was followed by a series of Langmuir and Freunlinch adsorption isotherms. The adsorption percent and distribution coefficient for nanoporous ZnO powders were 98.65 % ± 1.05 and 7,304 mL g−1, respectively. The optimum conditions were found as at pH 5.0, contact time 1 h, at 1/5 Zn2+/urea ratio, 50 ppm U(VI) concentration and 303 K. The monomolecular adsorption capacity of nanoporous ZnO powders for U(VI) was found to be 1,111 mg g−1 at 303 K. Using the thermodynamic equilibrium constants obtained at different temperatures, various thermodynamic parameters, such as ΔG°, ΔH° and ΔS°, have been calculated. Thermodynamic parameters (ΔH° = 28.1 kJ mol −1, ΔS° = 160.30 J mol−1 K−1, ΔG° = −48.54 kJ mol−1) showed the endothermic and spontaneous of the process. The results suggested that nanoporous ZnO powders was suitable as sorbent material for recovery and adsorption of U(VI) ions from aqueous solutions.

Sorption Characteristics of Cu ( II ) and Pb ( II ) onto Syrian Modified Bentonite

Syrian bentonite clay has been modified by sodium aluminate, and we studied exchange adsorption capacities, removal efficiency, distribution coefficients, and adsorption kinetics of Cu(II) and Pb(II) ions from aqueous solutions over a concentration range of 0.0125- 0.1 mol/L, shaking time of 72 hrs, and modified bentonite mass from 1.0 to 3 g. The sorption process of both cations follows the pseudo second-order kinetics, and the removal efficiency of about 100% was observed, and the maximum exchange adsorption capacities were 3.10 mmol/g and 2.10 mmol/g for Cu(II) and Pb(II) ions respectively, whereas the distribution coefficients were 307 mg/L for copper and 175 mg/L for lead ions.

Numerical modeling of contaminant transport in a stratified heterogeneous aquifer with dipping anisotropy

The combined influence of dip angle and adsorption heterogeneity on solute transport mechanisms in heterogeneous media can be understood by performing simulations of steady-state flow and transient transport in a heterogeneous aquifer with dipping anisotropy. Reactive and non-reactive contaminant transport in various types of heterogeneous aquifer is studied by simulations. The hydraulic conductivity (K) of the heterogeneous aquifer is generated by HYDRO_GEN with a Gaussian correla- tion spectrum. By considering the heterogeneity of the adsorption distribution coefficient (Kd), a perfect negative correlation between lnK and lnKd is obtained by using the spherical grains model. The generated K and Kd are used as input to groundwater flow and transport models to investigate the effects of dipping sedimentary heterogene- ity on contaminant plume evolution. Simulation results showed that the magnitude of the dip angle strongly controls the plume evolution in the studied anisotropic and heterogeneous aquifer. The retarded average pore-water velocity (v/R) of the adsorption model significantly controls the horizontal spreading of the plume. The bottom plume is intensively retarded in the zones between the dipping lenses of lower hydraulic conductivity and the no-flow bottom boundary. The implications of these findings are very important for the management of contaminated heterogeneous aquifers.

Pesticide leaching from two Swedish topsoils of contrasting texture amended with biochar

The use of biochar as a soil amendment has recently increased because of its potential for long-term soil carbon sequestration and its potential for improving soil fertility. The objective of this study was to quantify the effects of biochar soil incorporation on pesticide adsorption and leaching for two Swedish topsoils, one clay soil and one loam soil. We used the non-reactive tracer bromide and the pesticides sulfosulfuron, isoproturon, imidacloprid, propyzamid and pyraclostrobin, substances with different mobility in soil. Adsorption was studied in batch experiments and leaching was studied in experiments using soil columns (20 cm high, 20 cm diameter) where 0.01 kg kg(-1) dw biochar powder originating from wheat residues had been mixed into the top 10 cm. After solute application the columns were exposed to simulated rain three times with a weekly interval and concentrations were measured in the effluent water. The biochar treatment resulted in significantly larger adsorption distribution coefficients (Kd) for the moderately mobile pesticides isoproturon and imidacloprid for the clay soil and for imidacloprid only for the loam soil. Relative leaching of the pesticides ranged from 0.0035% of the applied mass for pyraclostrobin (average Kd=360 cm3 g(-1)) to 5.9% for sulfosulfuron (average Kd=5.6 cm3 g(-1)). There were no significant effects of the biochar amendment on pesticide concentrations in column effluents for the loam soil. For the clay soil concentrations were significantly reduced for isoproturon, imidacloprid and propyzamid while they were significantly increased for the non-mobile fungicide pyraclostrobin suggesting that the transport was facilitated by material originating from the biochar amendment.

Removal mechanisms and kinetics of trace tetracycline by two types of activated sludge treating freshwater sewage and saline sewage

Understanding the removal mechanisms and kinetics of trace tetracycline by activated sludge is critical to both evaluation of tetracycline elimination in sewage treatment plants and risk assessment/management of tetracycline released to soil environment due to the application of biosolids as fertilizer. Adsorption is found to be the primary removal mechanism while biodegradation, volatilization, and hydrolysis can be ignored in this study. Adsorption kinetics was well described by pseudo-second-order model. Faster adsorption rate (k 2 = 2.04 × 10−2 g min−1 μg−1) and greater adsorption capacity (q e = 38.8 μg g−1) were found in activated sludge treating freshwater sewage. Different adsorption rate and adsorption capacity resulted from chemical properties of sewage matrix rather than activated sludge surface characteristics. The decrease of tetracycline adsorption in saline sewage was mainly due to Mg2+ which significantly reduced adsorption distribution coefficient (K d) from 12,990 ± 260 to 4,690 ± 180 L kg−1. Species-specific adsorption distribution coefficients followed the order of K_{mathrm{d}}^{{ + 00}} gg K_{mathrm{d}}^{{ + - 0}} > K_{mathrm{d}}^{{ + - - }} . Contribution of zwitterionic tetracycline to the overall adsorption was >90 % in the actual pH range in aeration tank. Adsorption of tetracycline in a wide range of temperature (10 to 35 °C) followed the Freundlich adsorption isotherm well.Electronic supplementary materialThe online version of this article (doi:10.1007/s11356-012-1213-5) contains supplementary material, which is available to authorized users.

Sorption Behaviour of 137Cs on Kaolinit

The aim of this study was to carry out a systematic investigation of the adsoption of 137Cs on to Kaolinite clay mineral from Balikesir region which is west of Turkey. The adsorption behavior of kaolinite mineral was studied by means of a batch method using 137Cs as a radio tracer. Experiments were carried out for clay size of 30.00 μm and six different initial concentrations of 137Cs. In experiments, solid/ liquid ratio and contact time were determined to be 250 mL/g and 60 minutes, respectively. Adsorption percent (Ads%) and distribution coefficient (Kd) values were calculated according to the adsorption experiment results. After Langmuir Isotherm was applied, the clay adsorption capacity was calculated using Least Squares Method. It was observed that Ads% and Kd values decreased with increasing the liquid phase concentrations ranging from 1.68x10-4 M to 5.88x10-4 M. The constants depending on adsorption energy (b), adsorption capacity (Xm), and removal efficiency (R) were determined to be 17.56×103 mg/kg, 0.038 L/g and 93%, respectively. Kaolinite was found to be having both a good adsorption capacity and a rapid adsorption rate for 137Cs.

Adsorption of tetracycline on soil and sediment: Effects of pH and the presence of Cu(II)

Tetracycline (TC) is frequently detected in the environment, however, knowledge on the environmental fate and transport of TC is still limited. Batch adsorption experiments of TC by soil and sediment samples were conducted. The distribution of charge and electrostatic potential of individual atoms of various TC species in the aqueous solution were determined using MOPAC version 0.034 W program in ChemBio3D Ultra software. Most of the adsorption isotherms on the soil, river and marine sediments were well fitted with the Freundlich and Polanyi-Manes (PMM) models. The single point organic carbon (OC)-normalized adsorption distribution coefficients ( K OC) and PMM saturated adsorption capacity ( Q OC 0) values of TC were associated with the mesopore volume and clay content to a greater extent, indicating the mesopore volume of the soil and sediments and their clay content possibly influenced the fate and transport of TC in the natural environment. The adsorption of TC on soil and sediments strongly depended on the pH and presence of Cu(II). The presence of Cu(II) facilitated TC adsorption on soil and sediments at low pH (pH < 5), possibly due to the metallic complexation and surface-bridging mechanism by Cu(II) adsorption on soil and sediments. The cation exchange interaction, metallic complexation and Coulombic interaction of mechanisms for adsorption of TC to soils and sediments were further supported by quantum chemical calculation of various TC species in different pH.

NUMERICAL MODELING OF CONTAMINANT TRANSPORT IN FRACTURED POROUS MEDIA USING MIXED FINITE-ELEMENT AND FINITEVOLUME METHODS

A mathematical model for contaminant species passing through fractured porous media is presented. In the numerical model, we combine two locally conservative methods, i.e. mixed finite element (MFE) and the finite volume methods. Adaptive triangle mesh is used for effective treatment of the fractures. A hybrid MFE method is employed to provide an accurate approximation of velocities field for both the fractures and matrix which are crucial to the convection part of the transport equation. The finite volume method and the standard MFE method are used to approximate the convection and dispersion terms respectively. The model is used to investigate the interaction of adsorption with transport and to extract information on effective adsorption distribution coefficients. Numerical examples in different fractured media illustrate the robustness and efficiency of the proposed numerical model.

Adsorption and isothermal models of atrazine by zeolite prepared from Egyptian kaolin

The adsorption behavior of Atrazine on zeolites, prepared from Egyptian kaolin, has been studied in order to consider the application of these types of zeolites in water purification. The batch mode has been employed, using atrazine solution of concentration ranging from 2 to 10 mg /l. The adsorption capacity and distribution coefficients ( K d) were determined for the adsorption system as a function of sorbate concentration. It was found that, under the studies concentrations, the percent of adsorbed atrazine on both zeolites match to Langmuir and Freundlich adsorption models. The constants of each model were calculated to assess the adsorption behavior of atrazine on each type of zeolite. According to the equilibrium studies, adsorption of atrazine on zeolite X at lower concentrations is much better than that on zeolite A. The application of Dublin–Kaganer–Radushkevich model revealed physisorption endothermic adsorption process for both zeolites. These results show that natural zeolites hold great potential to remove hazardous materials such as atrazine from water.

Sorption of the antiparasitic drug eprinomectin in three soils

Batch equilibrium studies were conducted to determine eprinomectin partitioning behavior in three Greek soils (agricultural, pastoral and riparian soil). An analytical method was developed to quantify eprinomectin in aqueous 0.01 M CaCl 2. Recovery was 95% and limits of detection and quantification were both 0.005 mg L −1. An existing method for its quantification in soil was successfully tested in this study. Mass balance determinations showed that we accounted for 89–98% of the eprinomectin spiked in 5 g soil/25 mL 0.01 M CaCl 2. The concentration specific adsorption distribution coefficient ( K d ads ) ranged from 6.4 to 21.4 L kg −1 while concentration specific desorption distribution coefficient ( K d des ) ranged from 23.2 to 124.6 L kg −1. The Freundlich model adequately described adsorption and desorption with n values from 0.6 to 1.07. Hysteresis between adsorption and desorption was observed in two (agricultural and pastoral) soils. Moreover, eprinomectin binding to the clay mineral vermiculite and natural peat was tested. The drug binds to both materials. Hydroxyl groups and the nitrogen group present in eprinomectin are probably responsible for the binding to vermiculite. Coefficient K d ads significantly correlated with cation exchange capacity (CEC), Fe and Cu content of the soils when data for eprinomectin and data for ivermectin and abamectin were combined. These could be evidence that eprinomectin fate is related not only to organic matter (lipophilic binding) but also to clay content and other charged inorganic groups typically present in the soil environment.

Adsorption of Glutaric Acid and Glyoxylic Acid onto Weakly Basic Ion-Exchange Resin: Equilibrium and Kinetics

Adsorption equilibria of glutaric acid and glyoxylic acid on a weakly basic ion-exchanger which has a tertiary amine functional group were investigated experimentally and theoretically in this study. Amberlite IRA-67 was used as the ion-exchange resin. The time to reach an equilibrium state, effects of amount of adsorbent, temperature, and initial acid concentrations on adsorption efficiency and distribution coefficient of acid adsorption were investigated, experimentally. The Langmuir, Freundlich, and Temkin adsorption isotherms were calculated. The equilibrium isotherms were significantly dependent on initial acid concentration. The Langmuir isotherm was found to best represent the data for both acids. The adsorption of both acids followed pseudosecond-order kinetics. Diffusion is not the only rate-controlling step.

Adsorption, desorption and dissipation of metolachlor in surface and subsurface soils

Variations in soil properties with depth influence retention and degradation of pesticides. Understanding how soil properties within a profile affect pesticide retention and degradation will result in more accurate prediction by simulation models of pesticide fate and potential groundwater contamination. Metolachlor is more persistent than other acetanilide herbicides in the soil environment and has the potential to leach into groundwater. Reasonably, information is needed about the dissipation and eventual fate of metolachlor in subsoils. The objectives were to evaluate the adsorption and desorption characteristics and to determine the dissipation rates of metolachlor in both surface and subsurface soil samples. Adsorption of metolachlor was greater in the high-organic-matter surface soil than in subsoils. Lower adsorption distribution coefficient (K(ads)) values with increasing depth indicated less adsorption at lower depths and greater leaching potential of metolachlor after passage through the surface horizon. Desorption of metolachlor showed hysteresis, indicated by the higher adsorption slope (1/n(ads)) compared with the desorption slope (1/n(des)). Soils that adsorbed more metolachlor also desorbed less metolachlor. Metolachlor dissipation rates generally decreased with increasing soil depth. The first-order dissipation rate was highest at the 0-50 cm depth (0.140 week(-1)) and lowest at the 350-425 cm depth (0.005 week(-1)). Degradation of the herbicide was significantly correlated with microbial activity in soils. Metolachlor that has escaped degradation or binding to organic matter at the soil surface might leach into the subsurface soil where it will dissipate slowly and be subject to transport to groundwater.

Removal of some heavy metal cations by synthetic resin purolite C100

The discharge of heavy metals into aquatic ecosystems has become a matter of concern over the last few decades. These pollutants are introduced into the aquatic systems significantly as a result of various industrial operations. This paper describes the adsorption behaviour of cation exchange resin purolite C100 with respect to Ce 4+, Fe 3+ and Pb 2+ in order to consider its application to purify metal finishing wastewaters. The batch method has been employed, using metal concentrations in solution ranging from 2.65 to 265 mg/L. The adsorption percentages (%) and distribution coefficient ( K d) were determined for the adsorption system in the aqueous media as a function of sorbate concentration. The experimental isotherm data were analyzed using the Langmuir, Freundlich, and Dubinin–Kaganer–Radushkevich (DKR) equations. It was found that the adsorption phenomena depend on charge density and hydrated ion diameter. According to the equilibrium studies, the metal ions sequence can be given as Ce 4+ > Fe 3+ > Pb 2+. These results show that cation exchange resin purolite C100 holds great potential to remove cationic heavy metal species from polluted wastewater.

Adsorption of sulfur dioxide on natural clinoptilolite chemically modified with salt solutions

Various ion exchange forms of preliminary partly decationised zeolite (hydrogen forms) were obtained by indirect modification with metal salt solutions, as well as by direct treatment of natural clinoptilolite taken from Bulgarian deposits. Direct modification leads to a higher extent of samples enrichment with corresponding ion. Independently of the conditions, the alkaline and alkaline earth metal ions (especially sodium and calcium) were inserted at a greater extent, while the transitional metals—at a comparatively lower extent. The cationic forms of clinoptilolite were used for adsorption and desorption experiments. The breakthrough adsorption curves and the concentration curves at temperature-programmed desorption were obtained and compared. The breakthrough and saturation times, the adsorption capacity, the distribution coefficient, the adsorbed SO 2, the portions desorbed as SO 2 and SO 3, respectively, as well as the not desorbed portion of SO 2, were determined using these curves. It was established that a definite quantity of undesorbed SO 2 has remained in the zeolite forms modified with transitional metal cations. This statement was proved not only by the comparison between the adsorbed and desorbed quantities, but also by three-cycle adsorption–desorption experiments for the Cu 2+-form. The results demonstrate a decrease in the capacity for each following cycle in an extent similar to the undesorbed SO 2 quantity. It was not observed a visible difference in the values of the distribution coefficients for adsorption on identical cation forms, directly or indirectly obtained. However, the breakthrough time of the samples obtained by ion exchange of the hydrogen form was longer in all cases. Definite quantities of desorbed SO 3 were registered for all forms, except for the natural clinoptilolite and the samples enriched with alkaline and alkaline earth metal cations.

Adsorption studies of the herbicide simazine in agricultural soils of the Aconcagua valley, central Chile

Simazine is a s-triazine herbicide that has been applied worldwide for agriculture. This herbicide is the second most commonly detected pesticide in surface and groundwater in the United States, Europe and Australia. In this study, simazine adsorption behaviour was studied in two agricultural soils of the Aconcagua valley, central Chile. The two studied soils were soil A (loam, 8.5% organic matter content) and soil B (clay-loam, 3.5% organic matter content). Three times higher simazine adsorption capacity was observed in soil A (68.03 mg kg −1) compared to soil B (22.03 mg kg −1). The simazine adsorption distribution coefficients ( K d) were 9.32 L kg −1 for soil A and 7.74 L kg −1 for soil B. The simazine adsorption enthalpy in soil A was −21.0 kJ mol −1 while in soil B the adsorption enthalpy value was −11.5 kJ mol −1. These results indicate that simazine adsorption process in these soils is exothermic, governing H bonds the adsorption process of simazine in both the loam and clay-loam soils. These results and the potentiometric profiles of both soils, suggest that simazine adsorption in soil A is mainly governed by simazine–organic matter interactions and in soil B by simazine–clay interactions. The understanding of simazine sorption–desorption processes is essential to determine the pesticide fate and availability in soil for pest control, biodegradation, runoff and leaching.

Factors impacting on pharmaceutical leaching following sewage application to land

Sewage effluent application to land is a treatment technology that requires appropriate consideration of various design factors. Soil type, level of sewage pre-treatment and irrigation rate were assessed for their influence on the success of soil treatment in removing pharmaceuticals remaining after conventional sewage treatment. A large scale experimental site was built to assess treatment performance in a realistic environment. Of the factors investigated, soil type had the biggest impact on treatment performance. In particular, carbamazepine was very efficiently removed (>99%) when irrigated onto a volcanic sandy loam soil. This was in contrast to irrigation onto a sandy soil where no carbamazepine removal occurred after irrigation. Differences were likely caused by the presence of allophane in the volcanic soil which is able to accumulate a high level of organic matter. Carbamazepine apparent adsorption distribution coefficients ( K d) for both soils when irrigated with treated sewage effluent were determined as 25 L kg −1 for the volcanic soil and 0.08 L kg −1 for the sandy soil. Overall, a volcanic soil was reasonably efficient in removing carbamazepine while soil type was not a major factor for caffeine removal. Removal of caffeine, however, was more efficient when a partially treated rather than fully treated effluent was applied. Based on the investigated pharmaceuticals and given an appropriate design, effluent irrigation onto land, in conjunction with conventional sewage treatment may be considered a beneficial treatment for pharmaceutical removal.

Development of a Method for Chromium Speciation by Selective Solid Phase Extraction and Preconcentration on Alumina-Functionalized Thiosemicarbazide

A speciation method is developed for Cr(III) and Cr(VI) at selected medium pH range via solid phase extraction on three designed and synthesized chelating inorganic solid sorbents based on adsorption of thiosemicarbazide, as the nitrogen and sulfur containing chelating compound, on alumina surface [Al-TSC (I–III)]. The influence of various parameters including medium pH, time of contact, and interference of matrix and coexistent elements on the speciation and selective extraction processes of chromium species are studied and evaluated on the basis of determination of the metal adsorption capacity, distribution coefficient, and separation factor. Quantitative recovery of Cr(VI) was accomplished by [Al-TSC (I–III)] at pH = 1.0, while Cr(III) was found to be recovered on these sorbents at pH = 7.0 with minimal or no interference between these two species under the studied buffering conditions. The proposed method has been successfully applied for speciation, selective extraction, and preconcentration of Cr(III) and Cr(VI) in water samples with a preconcentration factor of 200.