Oxidized multiwalled carbon nanotubes modified with 2-(2-hydroxy-5-nitrophenyl)-4,5-diphenyl imidazole for solid phase extraction and preconcentration of some metal ions

In this work, a new procedure for the enrichment of the trace amount of Cu²⁺, Ni²⁺, Co²⁺, Pb²⁺, Fe²⁺, and Zn²⁺ ions based on the utilization of multiwalled carbon nanotubes (MWCNT) modified with 2-(2-hydroxy-5-nitrophenyl)-4,5-diphenyl imidazole as chelating agent prior to their determination by flame atomic absorption spectrometry has been described. The influence of effective parameters including pH, amount of ligand and MWCNT, composition of eluent, and coexisting ions on recoveries of understudy metal ions was examined. At the optimum pH of 5.0, all metal ions were quantitatively sorbed onto the proposed solid phase and completely desorbed with 8?mL of 5.0?mol?L^?1 HNO₃. The detection limit of Cu²⁺, Co²⁺, Ni²⁺, Pb²⁺, Fe²⁺, and Zn²⁺ ions was 1.7, 2.4, 2.3, 2.9, 2.8, and 1.4?µg?L^?1, while the preconcentration factor was 63 for Cu²⁺ and 94 for the other metal ions and relative standard deviations between 1.8 less than 3.0%. The proposed procedure was applied for the analysis of various samples.     

Retention of 137cesium in acid sulphate soils of South Central Thailand

Adsorption and desorption of ¹³⁷Cs by acid sulphate soils from the Nakhon Nayok province, South Central Plain of Thailand located near the Ongkarak Nuclear Research Center (ONRC) were investigated using a batch equilibration technique. The influence of added limestone (12 and 18 tons ha^?1) on ¹³⁷Cs adsorption–desorption was studied. Based on Freundlich isotherms, both adsorption and desorption of ¹³⁷Cs were nonlinear. A large portion (98.26–99.97%) of added ¹³⁷Cs (3.7?×?10³?7.03?×?10⁵ Bq l^?1) was sorbed by the soils with or without added lime. The higher lime treatments, however, favoured stronger adsorption of ¹³⁷Cs as compared with soil with no lime, which was supported by higher K _ads values. The addition of lime, the cation exchange capacity and pH of the soil increased and hence favoured the stronger adsorption of ¹³⁷Cs. Acid sulphate soils with a high clay content, medium to high organic matter, high CEC, and predominant clay types consisting of a mixture of illite, kaolinite, and montmorillonite were the main soil factors contributing to the high ¹³⁷Cs adsorption capacity. Competing cations such as NH₄ ⁺, K⁺, Na⁺, Ca²⁺, and Mg²⁺ had little influence on ¹³⁷Cs adsorption as compared with liming, where a significant positive correlation between K _ads and soil pH was observed. The ¹³⁷Cs adsorption–desorption characteristics of the acid sulphate soils studied exhibited a very strong irreversible sorption pattern. Only a small portion (0.09–0.58%) of ¹³⁷Cs adsorbed at the highest added initial ¹³⁷Cs concentration was desorbed by four successive soil extractions. Results clearly demonstrated that Nakhon Nayok province acid sulphate soils have a high ¹³⁷Cs adsorption capacity, which limits the ¹³⁷Cs bioavailability.     

Systematic characterization and chemical treatment of olive oil mill wastewater

Classic and centrifugal olive oil mill wastewater volumes of 1.18 and 1.68m³/Mg olives and corresponding polluting loads of 37 and 53 Kg BOD₅ and 82 and 121 Kg COD/Mg olives were established in a systematic study of 15 mills. Lime treatment at an optimum pH level near 11 requiring a dose less than 10g/l effected COD removals from 15 to 22% for classic and from 33 to 46% for centrifugal mill waste. The volume of resulting sludge was large and could not be adequately handled by sedimentation; the sludge had good dewatering characteristics and was amenable to simple straining. Excess lime treatment using up to 50 g/l lime offered little additional benefit.     

Carbon isotope effects during precipitation of barium carbonate: implications for environmental studies

Here we demonstrate that precipitation of dissolved inorganic carbon (DIC) to at pH 10.26, 11.38 and 12.11 does not cause measurable carbon isotope fractionation. However, NaOH solution prepared under standard laboratory procedure and used to increase pH value for precipitation of BaCO₃ can be contaminated by atmospheric CO₂. In our experiment, δ¹³C value in the contaminant DIC was −24.30‰, which resulted in decrease in the δ¹³C(DIC) value by 0.03, 0.07 and 0.22 at pH 10.26, 11.38 and 12.11, respectively.     

Acute toxicity of copper oxide nanoparticles to Daphnia magna under different test conditions

The acute toxicity of monodispersed 6 nm and <100 nm poly-dispersed copper oxide nanoparticles toward Daphnia magna was assessed using 48 h immobilization tests. CuSO₄ was used as a reference. Four different exposure conditions were tested, to study whether the toxicity of the nanoparticle suspensions changed in a way similar to what is known for dissolved Cu: first in ISO standard test conditions (pH 7.8), second with slight acidity (pH 6.5), third in the presence of citric acid, and fourth in the presence of humic acid. For all four exposure conditions, the toxicity of Cu employed in the three forms followed the same sequence, i.e., CuSO₄ > monodispersed 6 nm CuO ? poly-dispersed CuO. The toxicity of all Cu forms decreased from pH 6.5, ? pH 7.8, > pH 7.8 + citric acid, to ? pH 7.8 + humic acid. This pattern is in agreement with concentrations of Cu²⁺ calculated using the equilibrium model MINTEQ. These findings show that the acute toxicity of copper oxide nanoparticles is governed by test water composition and the chemical species Cu²⁺.     

Experimental determination of Cd2+ adsorption mechanism on low-cost biological waste

Carbonate shells have an astonishing ability in the removal of Cd²⁺ in a short time period with emphasis on being a low cost adsorbent. In the present study, the sorption capacity of carbonate shells was studied for Cd²⁺ in batch experiments. The influence of different carbonate shell sizes and physico-chemical factors were evaluated and the results were analyzed for its correlation matrices by using Predictive Analytics Software (PASW). The mineralogy state of aqueous solution regarding the saturation index was simulated using PHREEQC to identify the Cd²⁺ uptake mechanism. The Cd uptake rates were calculated as well as Ca²⁺, HCO ₃ ^? concentration, pH, ambient humidity and temperature were measured. Cd²⁺ removal of 91.52% was achieved after 5 h adsorption. The adsorption efficiencies were significantly influenced by pH as they increased with the increase of pH from acidic solution (5.50±0.02) to slightly alkaline (7.60±0.05). In addition, the mineralogy state of aqueous solution calculated from PHREEQC confirmed that the increment of Ca²⁺ and HCO ₃ ^? concentrations in solution was attributed to the dissolution of carbonate shells. Moreover, the ion exchange adsorption mechanism of Cd²⁺ toward Ca²⁺ was identified as the process involved in Cd²⁺ uptake.     

Use of zeolitized coal fly ash in the simultaneous removal of ammonium and phosphate from aqueous solution

Discharge of wastewater containing nitrogen and phosphate can cause eutrophication. Therefore, the development of an efficient material for the immobilization of the nutrients is important. In this study, a low calcium fly ash and high calcium fly ash were converted into zeolite using the hydrothermal method. The removal of ammonium and phosphate that coexist in aqueous solution by the synthesized zeolites were studied. The results showed that zeolitized fly ash could efficiently eliminate ammonium and phosphate at the same time. Saturation of zeolite with Ca²⁺ rather than Na⁺ favored the removal of both ammonium and phosphate because the cation exchange reaction by the NH₄ ⁺ resulted in the release of Ca²⁺ into the solution and precipitation of Ca²⁺ with PO₄ ^3? followed. An increase in the temperature elevated the immobilization of phosphate whereas it abated the removal of ammonium. Nearly 60% removal efficiency for ammonium was achieved in the neutral pH range from 5.5 to 10.5, while the increase or decrease in pH out of the neutral range lowered the adsorption. In contrast, the removal of phosphate approached 100% at a pH lower than 5.0 or higher than 9.0, and less phosphate was immobilized at neutral pH. However, there was still a narrow pH range from 9.0 to 10.5 favoring the removal of both ammonium and phosphate. It was concluded that the removal of ammonium was caused by cation exchange; the contribution of NH₃ volatilization to immobilization at alkaline conditions (up to pH level of 11.4) was limited. With respect to phosphate immobilization, the mechanism was mainly the formation of precipitate as Ca₃(PO₄)₂ within the basic pH range or as FePO₄ and AlPO₄ within acidic pH range.     

Attenuation of metal species in acidic solutions using bentonite clay: implications for acid mine drainage remediation

A laboratory batch experimental study has been carried out to evaluate the adsorption capacity of selected metal species in acid mine drainage (AMD) by bentonite clay. Bentonite clay was mixed with simulated AMD at specific solid–liquid (S/L) ratios and agitated in a reciprocating shaker and adsorption of selected toxic metals assessed over time. Cation exchange capacity varied from 1140 to 1290 meq kg^?1. Contact of AMD with bentonite leads to increase in pH and a possible reduction in electrical conductivity and total dissolved solids. At constant agitation time of 60 min, the pH increased with dosage of bentonite. Removal of Mn²⁺, Al ³⁺, and Fe³⁺ was observed to be greatest at 60 min of agitation. Bentonite clay exhibits high adsorption for Al³⁺ and Fe³⁺ at concentration less than 300 mg L^?1, while the capacity for Mn²⁺ was observed to be lower. Adsorption capacity for SO₄^2? was low with a great percentage of the SO₄^2? remaining in solution. Adsorption capacity of bentonite with more complex formulated AMD and gold tailing leachates was low for Fe³⁺, Al³⁺, and Mn²⁺. This indicates that optimum adsorption of bentonite clay is dependent on the chemistry of the AMD and its application might be site specific.     

Purification and some properties of β-N-acetyl-D-glucosaminidase from prawn (<Emphasis Type="Italic">Penaeus vannamei</Emphasis>)

The -N-acetyl-D-glucosaminidase (NAGase, EC 3.2.1.52) from prawn (Penaeus vannamei) was purified by extraction with 30% ethanol solution and ammonium sulfate fractionation, then chromatographed on Sephadex G-100 followed by DEAE-cellulose (DE-32) columns. The purified enzyme determined to be homogeneous by polyacrylamide gel electrophoresis (PAGE) and SDS-PAGE. The specific activity of the purified enzyme was 1,560 U mg^–1. Enzyme molecular weight was determined to be 105,000 Da; it contained two subunits of the same mass (45,000 Da). The pI value was calculated to be 4.8 by isoelectric focusing. The optimum pH and optimum temperature of the enzyme for the hydrolysis of pNP--D-GlcNAc (enzyme substrate) were determined to be pH 5.2 and 45°C, respectively. The behavior of the enzyme during hydrolysis of pNP--D-GlcNAc followed Michaelis–Menten kinetics, with K_m=0.254 mM and V_m=9.438 M min^–1, at pH 5.2 and 37°C. The stability of the enzyme was investigated, and the results showed that the enzyme was stable in a pH range from 4.2 to 10.0 and at temperatures <40°C. The effects of metal ions on the enzyme were also studied. Li⁺, Na⁺ and K⁺ had no influence on enzyme activity. Mg²⁺, Ca²⁺ and Mn²⁺ activated the enzyme, while Ba²⁺, Zn²⁺, Co²⁺, Cd²⁺, Hg²⁺, Pb²⁺ Cu²⁺, Fe³⁺ and Al³⁺ showed various degrees of inhibitory effects on the enzyme.Communicated by O. Kinne, Oldendorf/Luhe     

Effect of temperature on seawater desalination-water quality analyses for desalinated seawater for its use as drinking and irrigation water

The effect of feed seawater temperature on the quality of product water in a reverse osmosis process was investigated using typical seawater at Urla Bay, Izmir region, Turkey. The tests were carried out at different feed seawater temperatures (11–23°C) using two RO modules with one membrane element each. A number of variables, including pH, conductivity, total dissolved solids, salinity, rejection percentage of a number of ions (Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl⁻, HCO₃ ⁻, and SO₄ ²⁻), and the levels of boron and turbidities in collected permeates, were measured. The suitability of these permeates as irrigation and drinking water was checked by comparison with water quality standards.     

A Petrographic Investigation of two Sequential Extraction Techniques Applied to Anaerobic Canal Bed Mud

The application of sequential extraction procedures to determine metal speciation in sediments is fraught with uncertainty regarding what is actually dissolving or re-precipitating at each stage. In order to choose an appropriate scheme for the investigation of contaminated anaerobic mud two different sequential extraction procedures (Kersten and Förstner, 1986; Quevauviller, 1998) were investigated using a Cryogenic SEM (CryoSEM) technique coupled with energy dispersive X-ray analysis (EDXA). This enabled assessment of the degree of reagent selectivity and any re-precipitation associated with the respective methods. Analysis of the non-leached sediment revealed the most abundant authigenic minerals in order of decreasing abundance to be Fe²⁺-phosphate vivianite (Fe₃(PO₄)₂·8H₂O), mixed Fe, Zn, Cu sulphides, pyrite and calcite. After each stage of the sequential extraction the sediment residue was examined using CryoSEM. After extraction of the exchangeable fraction no obvious evidence of mineral dissolution was observed. Calcite was not completely dissolved during the carbonate extraction stage of either procedure. Vivianite began to dissolve in the carbonate extraction stage of both procedures and was completely dissolved by oxide extraction stage of both procedures. The sediment leached by acidified ammonium oxalate, contained abundant Fe oxalate crystals, suggesting that a large proportion of the Fe released from the vivianite has been re-precipitated. The Fe oxalate was then dissolved with the subsequent sulphide fraction. The technique used to extract the sulphide and organic fraction is the same in both schemes and no sulphide or metal rich organic matter was found in either residue.     

Application of Zr(IV) tungstate for removal of metal ions from aqueous solutions

A heteropolyacid Zr(IV) tungstate-based cation exchanger has been synthesized. An amorphous sample, prepared at pH 1.2 and having a Na⁺ ion exchange capacity of 0.92?meq?g^?1, was selected for further studies. Its physicochemical properties were determined using Fourier transform infrared spectrometer, X-ray diffraction, thermogravimetric, and scanning electron studies. To understand the cation exchange behavior of the material, distribution coefficients (K _d) for metal ions in various solvent systems were determined. Some important binary separations of metal ions, namely Mg²⁺–Bi³⁺, Cd²⁺–Bi³⁺, Fe³⁺–Bi³⁺, Th⁴⁺–Bi³⁺, and Fe³⁺–Zn²⁺, were achieved on such columns. The practical utility of these separations was demonstrated by separating Fe³⁺ and Zn²⁺ ions quantitatively in commercial pharmaceutical formulation. The cation exchanger has been successfully applied also for the treatment of industrial wastewater and a synthetic mixture. All the results suggests that Zr(IV) tungstate has excellent potential for the removal of metals from aqueous systems using packed columns of this material.     

Hydrogeochemistry study and groundwater quality assessment in the north of Isfahan,Iran

This study presents the groundwater quality assessment in the north of Isfahan, Iran. In the study area, assessment and measurement of groundwater hydrochemical parameters such as pH, total dissolved solids (TDS), electrical conductivity (EC), sodium absorption ratio (SAR), total hardness, major cations (K⁺, Na⁺, Ca²⁺ and Mg²⁺) and major anions (Cl^?, \({\text{HCO}}_{ 3}^{ - } ,{\text{CO}}_{3}^{2 - }\) and \({\text{SO}}_{4}^{2 - }\)) concentrations were performed. Accordingly, the 66 water samples from different locations were collected during April and May 2015. Water samples collected in the field were analyzed in the laboratory for cations and anions using the standard methods. In this research, the analytical results of physiochemical parameters of groundwater were compared with the standard guideline values as recommended by the world health organization (WHO) for drinking and public health purposes. The pH values of groundwater samples varied from 7.05 to 8.95 with a mean of 7.78, indicating a neutral to slightly alkaline water. TDS values showed that 14% of the samples exceeds the desirable limit given by WHO. EC values varied from 213 to 4320 µS/cm, while 23% of the samples were more than the standard limit. Gibbs diagram had shown that 90% of the samples in the study area fall in the rock weathering zone, and this means that chemical weathering of rock-forming minerals is the main factor controlling the water chemistry in the study area. Irrigation suitability and risk assessment of groundwater are evaluated by measuring EC, %Na, SAR and RSC. According to the dominant cations and anions, five types of water were identified in the water samples: Ca-HCO₃, Ca-SO₄, Na-Cl, Na-HCO₃ and Na-SO₄. The results show that the majority of samples (30 samples, 45%) belongs to the mixed Na-SO₄ water type. Correlation analysis and principal component analysis was used to identify the relationship between ions and physicochemical parameters. Results indicated that 18 stations of the study area had the best quality and can be used for irrigation and drinking purposes in the future.     

Solid phase extraction of trace metals from environmental samples using Amberlite XAD-7 loaded with 2-hydroxy-propiophenone-4-phenyl-3-thiosemicarbazone and determination by inductively coupled plasma–atomic emission spectrometry

A method for the solid phase extraction of trace metals, namely Co, Cu, Pb, Ni and Zn, from environmental and biological samples using column Amberlite XAD-7 loaded with 2-hydroxy-propiophenone-4-phenyl-3-thiosemicarbazone (HPPPTSC) and determination by inductively coupled spectrometry (ICP–AES) has been developed. The reagent has the capacity to form chelate complexes with the metals because of three binding sites in the reagent molecule. The optimum experimental conditions for the quantitative sorption of five metals, pH, effect of flow rate, concentration of eluent, sorption capacity and the effect of diverse ions on the preconcentration of analytes have been investigated. The sorption capacity of the resin has 83, 127, 35, 88 and 85?µmol?g^?1 for Co²⁺, Cu²⁺, Pb²⁺, Ni²⁺ and Zn²⁺, respectively. The preconcentration factors for Co²⁺, Cu²⁺, Pb²⁺, Ni²⁺ and Zn²⁺ were 100, 110, 120, 140 and 150, respectively. The accuracy of the proposed procedure was evaluated by standard reference materials. The achieved results were in good agreement with certified values. The proposed method was applied for the determination of trace metals in river water and plant leaves.     

Removal of Eu3+, Ce3+, Sr2+, and Cs+ ions from radioactive waste solutions by modified activated carbon prepared from coconut shells

As a biomass agricultural waste material, coconut shells were used for the preparation of high-quality modified activated carbon. Chemical modification of the surface of the prepared activated carbon is done by oxidation using H₂O₂ and HNO₃, respectively. The surface area and pore volume of the coconut shells activated carbon are increased by the chemical modification, and followingly the removal of the metals is improved. The structural morphology and composition of the modified activated carbon coconut shells (MACCS) were evaluated by Fourier transform infrared (FTIR) spectra, thermogravimetric analysis–differential thermal analysis (TGA-DTA), scanning electron microscope (SEM), X-ray diffraction (XRD), surface area analysis (SAA), X-ray fluorescence (XRF), and carbon, hydrogen, nitrogen, and sulfur (CHNS) elemental analysis. The prepared MACCS has reasonably good chemical stability. The influence of solution pH, contact time, adsorbent dosage, adsorption temperature, initial metal concentrations, and interfering ions on the adsorption performance of the investigated ions onto the prepared sorbent was examined by a batch method. The selectivity sequence for sorption of Eu³⁺, Ce³⁺, Sr²⁺, and Cs⁺ ions on MACCS was found to be Eu^3+?>?Ce^3+?>?Sr^2+?>?Cs⁺. The saturation capacities of MACCS for the studied metal ions were found to be 136.84, 85.55, 69.85, and 60.00?mg?g^?1 for Eu³⁺, Ce³⁺, Sr²⁺, and Cs⁺ ions, respectively. The thermodynamic parameters, ΔH°, ΔS°, and ΔG° were also evaluated.     

Study on degradation process of famotidine hydrochloride in aqueous samples

The kinetics of famotidine (FAM) transformation under the influence of various factors, important from the environmental point of view, was investigated in aqueous solutions. The degradation processes using UV, H₂O₂, UV/H₂O₂, H₂O₂/Fe²⁺, and UV/H₂O₂/Fe²⁺ were studied. Direct photolysis and H₂O₂-assisted photolysis showed a pseudo-first-order kinetics, while the Fenton and the photo-Fenton processes fit second-order kinetics. The provided experiments proved a high resistance of FAM to direct photolysis. Its stability depends highly on the pH of the reaction solutions. The rate of FAM direct photolysis in acidic solutions was almost negligible. The reaction rate of FAM photolysis at pH 8–9 was 3.7 × 10^?3 min^?1 with DT₅₀ about 3 h 7 min. It was found that the presence of H₂O₂ in the reaction environment enhances the rate of photolysis of FAM. The observed rates of reaction were 5.1 × 10^?3 min^?1 and 3.7 × 10^?3 min^?1 in acidic and basic solutions, respectively. The used Fenton systems appeared to be the most efficient in FAM removal. The rate of reaction depends on concentration of Fe²⁺ and H₂O₂. It was observed that the presence of UV-light enhances the reaction rate by two to six times in comparison to the classical Fenton system. Additionally, FAM behavior in natural water under solar irradiation was examined. The irradiation experiments were carried out in batch experiments with simulated sunlight.     

Studies on the content and nature of the phycocolloid from Corynomorpha prismatica (Rhodophyta,Cryptonemiales)

The phycocolloid from the red seaweed Corynomorpha prismatica J. Agardh (Cryptonemiales, Crateloupiaceae) has been investigated and found to show positive optical rotation ([] _D ²⁵ + 83^o), to be soluble in potassium chloride solution, to have a total sulphate content of 18.6±1.2% in unmodified gel and 15.0±0.9% in gel modified with lime. Total phycocolloid yields of 17.6±1.6% and 32.2±3.0% were obtained in gel extraction without lime and with lime added, respectively. The infrared spectra of the phycocolloid showed a broad absorption band at 860 to 800 cm^-1 and lacked single sharp peaks at 805 cm^-1. The phycocolloid was concluded to be a carrageenan akin to the lambda-type.     

The mechanism of calcification and its relation to photosynthesis and respiration in the scleractinian coral <Emphasis Type="Italic"> Galaxea fascicularis</Emphasis>

The mechanism of calcification and its relation to photosynthesis and respiration were studied with Ca²⁺, pH and O₂ microsensors using the scleractinian coral Galaxea fascicularis. Gross photosynthesis (Pg), net photosynthesis (Pn) and dark respiration (DR) were measured on the surface of the coral. Light respiration (LR) was calculated from the difference between Pg and Pn. Pg was about seven times higher than Pn; thus, respiration consumes most of the O₂ produced by the algal symbiont's photosynthesis. The respiration rate in light was ca. 12 times higher than in the dark. The coupled Pg and LR caused an intense internal carbon and O₂ cycling. The resultant product of this cycle is metabolic energy (ATP). The measured ATP content was about 35% higher in light-incubated colonies than in dark-incubated ones. Direct measurements of Ca²⁺ and pH were made on the outer surface of the polyp, inside its coelenteron and under the calicoblastic layer. The effects on Ca²⁺ and pH dynamics of switching on and off the light were followed in these three compartments. Ca²⁺ concentrations decreased in light on the surface of the polyp and in the coelenteron. They increased when the light was switched off. The opposite effect was observed under the calicoblastic layer. In light, the level of Ca²⁺ was lower on the polyp surface than in the surrounding seawater, and even lower inside the coelenteron. The concentration of calcium under the calicoblastic layer was about 0.6 mM higher than in the surrounding seawater. Thus Ca²⁺ can diffuse from seawater to the coelenteron, but metabolic energy is needed for its transport across the calicoblastic layer to the skeleton. The pH under the calicoblastic layer was more alkaline compared with the polyp surface and inside the coelenteron. This rise in pH increased the supersaturation of aragonite from 3.2 in the dark to 25 in the light, and brought about more rapid precipitation of CaCO₃. When ruthenium red was added, Ca²⁺ and pH dynamics were inhibited under the calicoblastic layer. Ruthenium red is a specific inhibitor of Ca-ATPase. The results indicated that Ca-ATPase transports Ca²⁺ across the calicoblastic layer to the skeleton in exchange for H⁺. Addition of dichlorophenyldimethylurea completely inhibited photosynthesis. The calcium dynamics under the calicoblastic layer continued; however, the process was less regular. Initial rates were maintained. We conclude that light and not energy generation triggers calcium uptake; however, energy is also needed.     

A simple ligandless microextraction method based on ionic liquid for the determination of trace cadmium in water and biological samples

A simple and efficient ionic liquid-based ligandless microextraction method has been developed for preconcentration of cadmium ions (Cd²⁺) as a step prior to its determination by flame atomic absorption spectrometry (FAAS) with a micro-sample introduction system. In this approach, the ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [C₄mim][PF₆] and ethanol were used as extractant and dispersive solvents to preconcentrate the Cd²⁺ in different waters, acid digested scalp hair, and nail samples. Some analytical parameters influencing the extraction efficiency of Cd²⁺ and its subsequent determination, including pH, IL volume, dispersant solvent volume, sample volume, temperature, incubation time, and matrix effect, were optimized. Under optimal conditions, the limit of detection (LOD), limit of quantification (LOQ), and enhancement factor (EF) were 0.4 μg L^?1, 1.3 μg L^?1, and 50, respectively. The relative standard deviation (RSD) of 100 μgL^?1 Cd²⁺ was 4.3% (n = 6). The validity of the proposed method was checked by determining Cd²⁺ in certified reference material (TM-25.3 fortified water) and standard addition; the results showed sufficient recovery (>98%) of Cd²⁺ within the certified value. The method was applied for preconcentration and determination of cadmium in waters and biological samples.