The adsorption of Pb(II) onto Turkish (Bandırma region) kaolinite clay was examined in aqueous solution with respect to the pH, adsorbent dosage, contact time, and temperature. The linear Langmuir ...and Freundlich models were applied to describe equilibrium isotherms and both models fitted well. The monolayer adsorption capacity was found as 31.75
mg/g at pH 5 and 20
°C. Dubinin–Radushkevich (D–R) isotherm model was also applied to the equilibrium data. The mean free energy of adsorption (13.78
kJ/mol) indicated that the adsorption of Pb(II) onto kaolinite clay may be carried out via chemical ion-exchange mechanism. Thermodynamic parameters, free energy (Δ
G°), enthalpy (Δ
H°) and entropy (Δ
S°) of adsorption were also calculated. These parameters showed that the adsorption of Pb(II) onto kaolinite clay was feasible, spontaneous and exothermic process in nature. Furthermore, the Lagergren-first-order, pseudo-second-order and the intraparticle diffusion models were used to describe the kinetic data. The experimental data fitted well the pseudo-second-order kinetics.
► A solid phase extraction procedure for allura red in water samples was presented. ► Analytical conditions like pH, flow rates, resin amount were investigated. ► The interference effect of some ...cations and anions was also studied. ► The validation of the procedure was performed by the method of standard addition.
A new, simple, rapid and sensitive solid phase extraction procedure based on separation and preconcentration of trace levels of allura red in water samples on MCI GEL CHP20P column system has been established. Optimal analytical conditions including pH, amount of allura red, flow rates of sample and eluent solutions, resin amount, sample volumes, etc. were investigated. The interference effect of some cations and anions was also studied. Preconcentration factor was found as 250. The detection limit (3 sigma) of the reagent blank for allura red was 2.35μgL−1. The determination of allura red levels in samples was performed by using spectrophotometry at 506nm. The relative standard deviations of the procedure were below 7%. The validation of the presented procedure was performed by the method of standard addition. The procedure was successfully applied to the determination of trace levels of allura red in tap water and waste water samples.
The equilibrium, thermodynamics and kinetics of the biosorption of Hg(II) onto moss (
Drepanocladus revolvens) biomass from aqueous solution were investigated. Optimum experimental parameters were ...determined to be pH 5.5, contact time 60
min, biomass concentration 4
g
L
−1 of solution, and temperature 20
°C. From the Langmuir model the maximum biosorption capacity of the moss biomass was found to be 94.4
mg
g
−1. The mean free energy value (10.2
kJ
mol
−1) evaluated by using the Dubinin–Radushkevich (D–R) model indicated that the biosorption of mercury ions onto
D. revolvens was taken place by chemical ion-exchange. The kinetic studies indicated that the biosorption process of mercury ions followed well pseudo-second-order model. The calculated thermodynamic parameters (Δ
G°, Δ
S°, Δ
H°) showed the biosorption to be exothermic and spontaneous with decreased randomness at the solid–solution interface. The recovery of the Hg(II) from
D. revolvens biomass was found to be 99% using 1
M HCl. It was concluded that the
D. revolvens biomass can be used as biosorbent for the treatment of wastewaters containing Hg(II) ions.
This paper presents the adsorption of Pb(II) and Cr(III) from aqueous solution on Celtek clay. Batch experiments were carried out as a function of the adsorbent dosage, solution pH, shaking time, and ...temperature. The equilibrium data of fitted well with the linear Langmuir and Freundlich models. Dubinin–Radushkevick (D–R) isotherm model was applied to describe the nature of the adsorption of the metals, and found that it occurred physically. Thermodynamic parameters, the change in Gibbs free energy change (Δ
G°), enthalpy (Δ
H°) and entropy (Δ
S°) were also calculated. These parameters indicated that the adsorption of Pb(II) and Cr(III) on Celtek clay was feasible, spontaneous and exothermic process in nature. Based on the results, it was concluded that Celtek clay had a significant potential for removing Pb(II) and Cr(III) from wastewater using adsorption method.
In this issue, Co(II), Pb(II), and Pd(II) were separated using an economical and green microextraction technique. The air agitation was used as a green co-factor with dispersive liquid–liquid ...microextraction solidified floating organic drop (AA-DLLME-SFO), which addresses the major drawbacks of the previous techniques. The procedure involved the use of folic acid, 1-undecanol and acetone as chelating agent, extraction solvent and disperser, respectively. Co(II), Pb(II), and Pd(II) detection limits were 0.042, 0.022, and 0.055 µg L
−1
, respectively. The preconcentration factors were 100 for all ions. For all metal ions investigated, the linearity has a wide range (0.5–100 µg L
−1
). The increased sensitivity depends on lower detection limits and higher preconcentration factors. Standard reference materials were used to ensure the accuracy of this approach. The selected procedure was used to measure trace quantities of heavy metals in river water and wastewater samples using flame atomic absorption spectrometry with great success. Finally, the greenness of the applied technique was assessed using two tools, the Green Analytical Procedure Index (GAPI) and Analytical Greenness Metric (AGREE). The GAPI graphic has eight green boxes, four yellow boxes, and three red boxes, and the AGREE index yields a total score of 0.78. The AA-DLLME-SFO approach is an environmentally friendly and sustainable procedure.
Graphical abstract
Polycyclic aromatic hydrocarbons (PAHs) are hazardous organic micropollutants that are ubiquitous as well as recalcitrant to degradation. They are generally found in wastewater bodies with proximity ...to gas production, oil exploration, and other processing industries. Therefore, their clean-up and removal techniques are of high importance. In this work, a novel adsorbent was developed by modification of palm date seed-derived activated carbon (AC) with acrylic acid-co-crotonic acid polymer. The effectiveness of the produced polymer-modified AC (PM-AC) in the simultaneous aquatic removal of naphthalene and fluorene was studied systematically. The physicochemical characteristics of the developed PM-AC adsorbent were assessed by FTIR, SEM, and EDX. The equilibrium data are well in agreement with the Langmuir isotherm model and the adsorption capacity of the PM-AC was determined as 2.76 mg g
−1
by considering this model. The adsorption mechanism of both PAHs onto the PM-AC adsorbent was well described by the pseudo-second-order kinetic model. The thermodynamic Δ
G
parameter showed the increased spontaneity of the PAHs adsorption with raising the temperature as the Δ
H
value confirmed the endothermic nature of the adsorption process. The π–π interactions were the key mechanisms of PAHs adsorption onto the prepared adsorbent. The PM-AC also demonstrated good adsorption performance in the case of a model wastewater sample containing some toxic heavy metals. The obtained findings revealed that the prepared PM-AC composite could be a promising adsorbent for developing cost-effective filters for the removal of PAHs from urban wastewaters. The PAHs levels were determined by using gas chromatography tandem mass spectrometry (GC–MS/MS). Recovery values were found nearly quantitative (≥ 95%).
The biosorption characteristics of As(III) and As(V) from aqueous solution using the macrofungus (
Inonotus hispidus) biomass were investigated as a function of pH, biomass dosage, contact time, and ...temperature. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models were applied to describe the biosorption isotherm of the metal ions by
I. hispidus biomass. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The biosorption capacity of
I. hispidus for As(III) and As(V) was found to be 51.9
mg/g and 59.6
mg/g, respectively at optimum conditions of pH 6 for As(III) and pH 2 for As(V), contact time of 30
min and temperature of 20
°C. The metal ions were desorbed from
I. hispidus using both 1
M HCl and 1
M HNO
3. The high stability of
I. hispidus permitted 10 times of adsorption–elution process along the studies with a decrease about 11–28% in recovery of As(III) and 10–25% for As(V). The mean free energy values evaluated from the D–R model indicated that the biosorption of As(III) and As(V) onto
I. hispidus biomass was taken place by chemical ion-exchange. The calculated thermodynamic parameters showed that the biosorption of As(III) and As(V) ions onto
I. hispidus biomass was feasible, spontaneous and exothermic under examined conditions. Kinetic examination of the experimental data were showed that the biosorption processes of both As(III) and As(V) followed well pseudo-second-order kinetics.
The biosorption potential of
Racomitrium lanuginosum as aquatic moss biosorbent for the removal of Pd(II) from aqueous solution was investigated. The effects of pH, biomass dosage, contact time, and ...temperature on the biosorption processes were systematically studied. Experimental data were modeled by Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherms. Langmuir isotherm model (
R
2
=
0.994) fitted the equilibrium data better than the Freundlich isotherm model (
R
2
=
0.935). The monolayer biosorption capacity of
R. lanuginosum biomass for Pd(II) was found to be 37.2
mg/g at pH 5. The mean free energy was calculated as 9.2
kJ/mol using the D–R isotherm model (
R
2
=
0.996). This result indicated that the biosorption of Pd(II) was taken place by chemical ion-exchange. The calculated thermodynamic parameters, Δ
G°, Δ
H° and Δ
S° showed that the biosorption of Pd(II) on
R. lanuginosum biomass was feasible, spontaneous and exothermic under examined conditions. Experimental data were also tested using the biosorption kinetic models. The results showed that the biosorption processes of Pd(II) on
R. lanuginosum followed well pseudo-second-order kinetics at 20–50
°C (
R
2
=
0.999).
We synthesized the poly(methyl methacrylate-co-2-aminoethyl methacrylate (PMaema) amphiphilic copolymer in a form of solid phase adsorbent. Then it was used for separation, preconcentration and ...determination of trace amount of As(III) ions from foods and waters with hydride generation atomic absorption spectrometry. The PMaema was characterized by fourier transform infrared spectrometer and nuclear magnetic resonance spectrometer. The adsorption of As(III) to the PMaema was also supported using computational chemistry studies. The experimental parameters (pH, PMaema amount, adsorption time and ethanol volume) were optimized using a three-level Box-Behnken design with four experimental factors. We observed linear calibration curve for the PMaema amount in the 10-500 ng L
range (R
= 0.9956). Limit of detection, preconcentration factor and sorbent capacity of PMaema were equal to 3.3 ng L
, 100 and 75.8 mg g
, respectively. The average recoveries (spiked at 50 ng L
) changes in the range of 91.5-98.6% with acceptable relative standard deviation less than 4.3%. After validation studies, the method was successfully applied for separation, preconcentration and determination of trace amount of As(III) from foods and waters.
A solid phase extraction method was developed for the preconcentration and separation of trace amounts of chromium, manganese, iron, cobalt, copper, cadmium and lead from environmental samples by ...complexation with alpha-benzoin oxime followed by adsorption onto Diaion SP-850-solid phase extraction column. One molar per liter HNO
3 was used as eluent. The recoveries of analytes at pH 8.0 with 700
mg of resin were greater than 95% without interference from alkaline, earth alkaline and some metal ions. The detection limits by three sigma for analyte ions were 0.65
μg
l
−1 for Cr(III), 0.42
μg
l
−1 for Mn(II), 0.28
μg
l
−1 for Fe(III), 0.73
μg
l
−1 for Co(II), 0.30
μg
l
−1 for Cu(II), 0.47
μg
l
−1 for Cd(II) and 0.50
μg
l
−1 for Pb(II). The validation of the procedure was performed by the analysis of the certified standard reference materials. The presented procedure was applied to the determination of analytes in tap, river and sea waters, rice, wheat, canned tomato and coal samples with successfully results (recoveries greater than 95%, R.S.D.'s lower than 8%).
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