Removal of Copper(II) and Zinc(II) Ions From Aqueous Solution by Chemical Treatment of Coal Fly Ash

The aim of this study was to investigate the chemical modifications of coal fly ash (CFA) treated with HNO3 or ammonium acetate (AcNH4) or NaOH or sodium diethyldithiocarbamate (NaDDTC) as an adsorbent for the removal of copper(II) and zinc(II) ions from aqueous solution. The morphology of fly ash grains before and after modification was examined via X-ray diffraction (XRD) and images of scanning electron microscope (SEM). Adsorption of copper(II) and zinc(II) ions was conducted under batch process at different duration, concentrations and temperature of the suspension. Equilibrium experiments shows that the selectivity of CFA-NaOH nanoparticles towards Cu(II) ions is greater than that of Zn(II) ions, which is related to their hydrated ionic radius and first hydrolysis equilibrium constant. The adsorption isotherms were described by Langmuir and Freundlich models. Kinetic data revealed that the adsorption fits well by the pseudo-second-order rate model with high regression coefficients. Thermodynamic parameters suggested that the immobilization Cu(II) and Zn(II) ions onto CFA-NaOH is a spontaneous process. Results demonstrated that the treating coal fly ash with alkaline solution was a promising way to enhance Cu(II) and Zn(II) ions adsorption

EVALUATION OF THE CONTENT OF SELECTED HEAVY METALS IN SAMPLES OF POLISH HONEYS

This paper presents the result of the determination of the total content of Cu, Pb and Zn by the method of atomic absorption spectrometry with atomization in an air-acetylene flame in Polish honeys samples. The research material was a honeydew, monofloral honey and buckwheat honey. For the mineralization of samples, the following solutions were applied: 1) HNO3(conc), 2) HNO3(conc) and H2O2(conc) in the volume ratio equal to 4:1 and 3:1. On the basis of the results and recommended food standards the percentage of the recommended dietary allowances (RDA) in connection with the consumption of 100 g of product were estimated. To verify the results validation of analytical method used was carried out. It was included defining the following validation parameters values: the limit of detection and quantification; linearity and measurement range; repeatability and accuracy of the results. The contamination of the analyzed honeys by Pb is higher than the acceptable level of contamination of this element. The highest contents of Cu and Zn were characterized by monofloral honeys

Comparison of adsorption of Cd(II) and Pb(II) ions on pure and chemically modified fly ashes

The study investigates chemical modifications of coal fly ash (FA) treated with HCl or NH4 HCO3 or NaOH or Na2 edta, based on the research conducted to examine the behaviour of Cd(II) and Pb(II) ions adsorbed from water solution on treated fly ash. In laboratory tests, the equilibrium and kinetics were examined applying various temperatures (293 - 333 K) and pH (2 - 11) values. The maximum Cd(II) and Pb(II) ions adsorption capacity obtained at 293 K, pH 9 and mixing time 2 h from the Langmuir model can be grouped in the following order: FA-NaOH > FA-NH 4 HCO 3 > FA > NaOH2edta > FA-HCl. The morphology of fly ash grains was examined via small-angle X-ray scattering (SAXS) and images of scanning electron microscope (SEM). The adsorption kinetics data were well fitted by a pseudo-second-order rate model but showed a very poor fit for the pseudo- first order model. The intra-particle model also revealed that there are two separate stages in the sorption process, i.e. the external diffusion and the inter-particle diffusion. Thermodynamics parameters such as free energy, enthalpy and entropy were also determined. A laboratory test demonstrated that the modified coal fly ash worked well for the Cd(II) and Pb(II) ion uptake from polluted waters

Effect of chemical modification of the coal fly ash onto adsorption of lead(ii) ions in the presence of cadmium(ii) ions in a singleand bi-component system

Celem badań było określenie wpływu modyfikacji chemicznej odpadowego lotnego popiołu węglowego (FA) za pomocą roztworów HNO3, CH3COONH4 (AcNH4), NaOH oraz dietyloditiokarbaminianu sodu (NaDDTC) na adsorpcję jonów ołowiu(II) w obecności jonów kadmu(II) w układzie jedno- i dwuskładnikowym. Analizowano modele izoterm adsorpcji w układzie jednoskładnikowym, m.in.: Freundlicha, Langmuira, Redlicha-Petersona, Jovanoviča, Fumkina- Fowlera-Guggenheima, Fowlera-Guggenheima-Jovanoviča-Freundlicha oraz Halseya, a także w układzie dwuskładnikowym za pomocą rozszerzonego modelu Langmuira, Langmuira- Freundlicha oraz Jaina-Snoeyinka. W testach laboratoryjnych badano równowagę oraz kinetykę adsorpcji. Adsorpcję jonów Pb(II) i Cd(II) w układzie jednoskładnikowym za pomocą FA, FA-NaOH i FA-AcNH4 dobrze opisuje model Langmuira oraz Redlicha-Petersona. Najwyższą wartość maksymalnej pojemności adsorpcyjnej uzyskano w przypadku FA-NaOH, która wynosiła 220 mg·g–1 s.m. oraz 55 mg·g–1 s.m. odpowiednio dla jonów Pb(II) i Cd(II). Badania wykazały, że FA-NaOH posiadają większą selektywność względem jonów Pb(II) niż względem jonów Cd(II), co jest związane z wielkością promienia uwodnionego jonu metalu i wartością pierwszej stałej równowagi reakcji hydrolizy. Otrzymane dane kinetyczne adsorpcji zostały dobrze wyrażone za pomocą modelu pseudo-drugiego rzędu (R2 = 0,998), natomiast wykazały bardzo słabe dopasowanie do modelu pseudo-pierwszego rzędu (R2 3, CH3COONH4 (AcNH4), and sodium diethyldithiocarbamate (NaDDTC) as an adsorbent for the removal of lead(II) and cadmium(II) ions in single- and bi-component system. In laboratory tests, the equilibrium and kinetic adsorption were examined. The adsorption isotherm models in single-component system were analysed, among others Freundlich, Langmuir, Redlich-Peterson, Jovanovič, Fumkin-Fowler-Guggenheim, Fowler-Guggenheim-Jovanovič-Freundlich, and Halsey, as well as in bi-component system by means of extended Langmuir, Langmuir-Freundlich, and Jain-Snoeyink models. The maximum Pb(II) and Cd(II) ions adsorption capacity obtained from the Langmuir model can be grouped in the following order: FA-NaOH > FA-AcNH4 > FA > FA-NaDDTC > FA-HNO3. Adsorption of Pb(II) and Cd(II) ions in single-component system, both the Langmuir and Redlich-Peterson models for the FA, FA-NaOH, and FA-AcNH4 could be fitted to experimental data. The maximum monolayer adsorption capacity of the FA-NaOH was found to be 220 mg·g–1 dry mass and 55 mg·g–1 dry mass for Pb(II) and Cd(II) ions respectively. Equilibrium experiments shows that the selectivity of FA-NaOH towards Pb(II) ions is greater than that of Cd(II) ions, which is related to their hydrated ionic radius and first hydrolysis equilibrium constant. The adsorption kinetics data were well fitted by a pseudo-second-order rate model (R2 = 0.998) but showed a very poor fit for the pseudo-first order model (R2 < 0.8). The Elovich and intra-particle model were analysed, also revealed that there are two separate stages in the sorption process, namely, the external diffusion and the inter-particle diffusion. It was found that the chemical enhancement of coal fly ash by NaOH treatment yields an effective and economically feasible material for the treatment of Pb(II) and Cd(II) ions-containing effluents

Wieloskładnikowa sorpcja oraz utylizacja odpadu stałego do jednoczesnego usuwania barwnika zasadowego i metalu ciężkiego z układu wodnego

The presented work introduces a simple modification of coal fly ash (FA) with 30% solution of H2O2, used as a new efficient sorbent for the removal of organic dye crystal violet (CV) in the presence of Cu(II) ions in single- and bi-component systems Cu(II)-CV. FT-IR, TG, SEM-EDS, and XRD suggested that the mechanism of Cu(II) and CV sorption onto FA-H2O2 includes ion-exchange and surface adsorption process. Comparing the values of the reduced chi-square test (χ2/DoF) and the determination coefficient R2 obtained for CV of the considered isotherms, the fitting degree follows the sequence: Jovanović > Langmuir > Elovich > Freundlich > Redlich-Peterson (R-P) > Tóth > Halsey > BET. Sorption of Cu(II) ions in a single system by means of FA-H2O2 was well fitted by the Langmuir and R-P model. The studies of equilibrium in a bi-component system by means of extended Langmuir (EL), extended Langmuir-Freundlich (ELF), and Jain-Snoeyink (JS) models were analysed. The estimation of parameters of sorption isotherms in a bi-component system Cu(II)-CV has shown that the best of fit calculated values of experimental data for both sorbates have been the EL model and the JS model, but only in the case of a CV dye. The sorption kinetic of Cu(II) and CV onto FA-H2O2 was discussed by means of the PFO, PSO, and intra-particle diffusion models.W pracy przedstawiono prostą modyfikację popiołu lotnego węglowego (FA) za pomocą 30% roztworu H2O2 oraz wykorzystanie go jako nowego skutecznego sorbentu do usuwania barwnika organicznego fioletu krystalicznego (CV) w obecności jonów Cu(II) w układzie jedno- i dwuskładnikowym Cu(II)-CV. Badania FT-IR, TG, SEM-EDS i XRD potwierdziły, że mechanizm sorpcji Cu(II) i CV na FA- H2O2 obejmuje proces wymiany jonowej i adsorpcji powierzchniowej. Porównując wartości zredukowanego testu chi-kwadrat (χ2/DoF) i współczynnika determinacji R2 uzyskane dla rozpatrywanych izoterm CV, stopień dopasowania odpowiednich modeli odpowiada następującej kolejności: Jovanović > Langmuir > Elovich > Freundlich > Redlich-Peterson (RP) > Tóth > Halsey > BET. Sorpcja jonów Cu(II) w układzie jednosładnikowym za pomocą FA-H2O2 została dobrze opisana za pomocą modelu Langmuira i R-P. Przeanalizowano badania równowagi w układzie dwuskładnikowym wykorzystując rozszerzony model Langmuira (EL), rozszerzony Langmuira-Freundlicha (ELF) i Jain-Snoeyinka (JS). Estymacja parametrów izoterm sorpcji w układzie binarnym Cu(II)-CV wykazała, że najlepsze dopasowanie wartości obliczonych do danych doświadczalnych dla obu sorbatów posiada model EL oraz model JS, ale tylko w przypadku barwnika CV. Kinetykę sorpcji Cu(II) i CV na FA-H2O2 przeanalizowano za pomocą modeli PFO, PSO i dyfuzji wewnątrzziarnowej