Functionalization of Zeolite NaP1 for Simultaneous Acid Red 18 and Cu(II) Removal

The efficiency of azo dye Acid Red 18 (AR18) and Cu(II) ions simultaneous removal from an aqueous solution on NaP1CS and NaP1H was investigated, taking into account the effect of the phase contact time, pH, initial concentration, temperature, and interfering ions presence. Zeolite denoted as NaP1CS was modified by chitosan (CS) and zeolite denoted as NaP1H was modified by hexadecyltrimethylammonium bromide (HDTMA). In order to characterize sorption properties of NaP1CS, the obtained sorbent was characterized using Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption/desorption (ASAP). The kinetic parameters were determined by means of the pseudo first order (PFO), pseudo second order (PSO), and intraparticle diffusion (IPD) kinetic models. To present the adsorption data, three different isotherm models (Langmuir, Freundlich and Dubinin-Radushkevich) were used. The desorption process was also examined. It was found that for sorbent NaP1CS the pseudo second order (PSO) kinetic model and the Langmuir isotherm fitted best the experimental data. Moreover, it was noted that the acidic pH is appropriate to achieve the best sorption properties of NaP1CS for Cu(II) and NaP1H for AR18 and Cu(II). The thermodynamic parameters indicate an endothermic process. The most effective solution for the desorption process was found to be 1 M HCl. The results indicate that simultaneous removal of dye AR18 and Cu(II) on modified zeolite NaP1CS or NaP1H is possible and proceeds with a very good efficiency. The obtained zeolites could effectively adsorb AR18 an Cu(II) simultaneously, but their adsorption abilities were rather different.

Removal of Heavy Metal Ions from One- and Two-Component Solutions via Adsorption on N-Doped Activated Carbon

This paper deals with the adsorption of heavy metal ions (Cu2+ and Zn2+) on the carbonaceous materials obtained by chemical activation and ammoxidation of Polish brown coal. The effects of phase contact time, initial metal ion concentration, solution pH, and temperature, as well as the presence of competitive ions in solution, on the adsorption capacity of activated carbons were examined. It has been shown that the sample modified by introduction of nitrogen functional groups into carbon structure exhibits a greater ability to uptake heavy metals than unmodified activated carbon. It has also been found that the adsorption capacity increases with the increasing initial concentration of the solution and the phase contact time. The maximum adsorption was found at pH = 8.0 for Cu(II) and pH = 6.0 for Zn(II). For all samples, better fit to the experimental data was obtained with a Langmuir isotherm than a Freundlich one. A better fit of the kinetic data was achieved using the pseudo-second order model.

Influence of Electrolyte Impurities from E-Waste Electrorefining on Copper Extraction Recovery

In order to reflect possible issues in future sole e-waste processing, an electrolyte of complex chemical composition reflecting system of sole e-waste processing was obtained by following a specially designed pyro-electrometallurgical method. The obtained non-standard electrolyte was further used for the purpose of comprehensive metal interference evaluation on the copper solvent extraction (SX) process. Optimization of the process included a variation of several process parameters, allowing determination of the effect of the most abundant and potentially the most influential impurities (Ni, Sn, Fe, and Zn) and 14 other trace elements. Moreover, comparing three commercial extractants of different active chelating groups, it was determined that branched aldoxime reagent is favorable for Cu extraction from the chemically complex system, as can be expected in future e-waste recycling. The results of this study showed that, under optimal conditions of 20 vol.% extractant concentration, feed pH 1.5, O/A ratio 3, and 10-min phase contact time, 88.1% of one stage Cu extraction was achieved. Co-extraction of the Fe, Zn, Ni, and Sn was under 8%, while Pb and trace elements were negligible. Optimal conditions (H2SO4 180 g/L, O/A = 2, and contact time 5 min) enabled 95.3% Cu stripping and under 6% of the most influential impurities. In addition, an impurity monitoring and distribution methodology enabled a better understanding and design of the process for the more efficient valorization of metals from e-waste.

Sorption of As (III) and Se (IV) from aqueous solutions for subsequent determination by total reflection X-ray fluorescence

An approach to the simultaneous isolation of As (III) and Se (IV) from solutions on a new S,N-containing sorbent followed by determination of the analyte in the sorbent phase using total reflection X-ray fluorescence (TXRF) has been proposed. To match the goal, a sorbent with a branched structure was synthesized on the base of polyacrylamide modified with formaldehyde and hydrogen sulfide. This is a heteroatomic copolymer containing sulfide bridges in the chain and crosslinking by a tertiary amine. Conditions for the quantitative co-extraction of As (III) and Se (IV), i.e., sorption in solutions of 1 M HNO3 with calcium ions present, heating to 60°C and phase contact time of 1 h were determined. The mechanism of sorption interaction of the analytes under specified conditions is discussed. It is shown that a 100-fold excess of iron, zinc and copper does not interfere with the extraction of analytes, thus providing the possibility of As (III) and Se (IV) isolation from different types of raw materials and processed products using the synthesized sorbent. A method for the direct XRF quantification of arsenic and selenium with sr 0.09 and 0.08, respectively, in the sorbent phase has been developed. The correctness of the results was confirmed by the ICP-MS method in analysis of aqueous reference solution after dissolution of the sorbate in HNO3 (1:1).

Carbon-Silica Composite as Adsorbent for Removal of Hazardous C.I. Basic Yellow 2 and C.I. Basic Blue 3 Dyes

Treatment of wastewaters containing hazardous substances such as dyes from the textile, paper, plastic and food industries is of great importance. Efficient technique for the removal of highly toxic organic dyes is adsorption. In this paper, adsorptive properties of the carbon-silica composite (C/SiO2) were evaluated for the cationic dyes C.I. Basic Blue 3 (BB3) and C.I. Basic Yellow 2 (BY2). The sorption capacities were determined as a function of temperature (924.6–1295.9 mg/g for BB3 and 716.3-733.2 mg/g for BY2 at 20–60 °C) using the batch method, and the Langmuir, Freundlich and Temkin isotherm models were applied for the equilibrium data evaluation using linear and non-linear regression. The rate of dye adsorption from the 100 mg/L solution was very fast, after 5 min. of phase contact time 98% of BB3 and 86% of BY2 was removed by C/SiO2. Presence of the anionic (SDS), cationic (CTAB) and non-ionic (Triton X-100) surfactants in the amount of 0.25 g/L caused decrease in BB3 and BY2 uptake. The electrokinetic studies, including determination of the solid surface charge density and zeta potential of the composite suspensions in single and mixed adsorbate systems, were also performed. It was shown that presence of adsorption layers changes the structure of the electrical double layer formed on the solid surface, based on the evidence of changes in ionic composition of both surface layer and the slipping plane area. The greatest differences between suspension with and without adsorbates was obtained in the mixed dye + SDS systems; the main reason for this is the formation of dye-surfactant complexes in the solution and their adsorption at the interface.

OBTAINING HIGH QUALITY LITHIUM CARBONATE FROM NATURAL LITHIUM-CONTAINING BRINES

The aim of this work is to develop a new effective technology for producing high-quality lithium carbonate from natural lithium-containing brines. Freshly deposited aluminum hydroxide was used to separate lithium from the trace amounts of sodium and calcium. It was found that the completeness of lithium extraction from brines purified from magnesium depends on the sorbent dosage, phase contact time, mineralization, pH, and brine temperature. To extract lithium from brines with a mineralization of less than 100 g/dm3, it is necessary to introduce 4 mol of aluminum hydroxide per 1 mol of lithium in the brine. For brines with a mineralization greater than 200 g/dm3, the consumption of the sorbent providing the extraction of lithium more than 96% is 2.5 mol of aluminum hydroxide. Desorption of lithium chloride from lithium-aluminum concentrate is carried out by processing 4-5 canopies of concentrate in a Soxlet type apparatus with the same volume of distilled water. The resulting concentrated solution of lithium chloride is purified from calcium impurities in contact with a saturated solution of lithium carbonate. From a heated aqueous solution of lithium chloride purified from calcium impurities, lithium carbonate is precipitated by dosing a stoichiometric amount of a saturated solution of sodium carbonate into it. The precipitate of lithium carbonate is separated from the mother solution, washed with three portions of a saturated solution of lithium carbonate at a ratio of solid to liquid by weight equal to one to five, in order of decreasing the concentration of sodium in each portion of the wash water. The dried product contains at least 99.6% Li2CO3.

Sorption of Se (IV) from aqueous solutions with subsequent determination by X-ray fluorescence analysis

An approach to sorptive separation of Se (IV) from solutions on a novel S,N-containing sorbent with subsequent determination of the analyte in the sorbent phase by micro-x-ray fluorescence method is presented. The sorbent copolymethylenesulfide-N-alkyl-methylenamine (CMA) was synthesized using «snake in the cage» procedure and proven to be stable in acid solutions. Conditions for quantitative extraction of Se (IV) were determined: sorption in 5 M HCl or 0.05 M HNO3 solutions when heated to 60°C, phase contact time being 1 h. The residual selenium content in the solution was determined by inductively coupled plasma mass spectrometry (ICP-MS) using 82Se isotope. The absence of selenium losses is proved and the mechanism of sorption interaction under specified conditions is proposed. The method of micro-x-ray fluorescence analysis (micro-RFA) with mapping revealed a uniform distribution of selenium on the sorbent surface. The possibility of determining selenium in the sorbent phase by micro-RFA is shown. When comparing the obtained results with the results of calculations by the method of fundamental parameters, it is shown the necessity of using standard samples of sorbates to obtain correct results of RFA determination of selenium in the sorbent phase.

Recovery of Lanthanum(III) and Nickel(II) Ions from Acidic Solutions by the Highly Effective Ion Exchanger

The recovery of La(III) and Ni(II) ions by a macroporous cation exchanger in sodium form (Lewatit Monoplus SP112) has been studied in batch experiments under varying HNO3 concentrations (0.2–2.0 mol/dm3), La(III) and Ni(II) concentrations (25–200 mg/dm3), phase contact time (1–360 min), temperature (293–333 K), and resin mass (0.1–0.5 g). The experimental data revealed that the sorption process was dependent on all parameters used. The maximum sorption capacities were found at CHNO3 = 0.2 mol/dm3, m = 0.1 g, and T = 333 K. The kinetic data indicate that the sorption followed the pseudo-second order and film diffusion models. The sorption equilibrium time was reached at approximately 30 and 60 min for La(III) and Ni(II) ions, respectively. The equilibrium isotherm data were best fitted with the Langmuir model. The maximum monolayer capacities of Lewatit Monoplus SP112 were equal to 95.34 and 60.81 mg/g for La(III) and Ni(II) ions, respectively. The thermodynamic parameters showed that the sorption process was endothermic and spontaneous. Moreover, dynamic experiments were performed using the columns set. The resin regeneration was made using HCl and HNO3 solutions, and the desorption results exhibited effective regeneration. The ATR/FT-IR and XPS spectroscopy results indicated that the La(III) and Ni(II) ions were coordinated with the sulfonate groups.

PROBABILITY-DETERMINED DESIGN PLANNING FOR DECOMPOSITION OF SILICON-CONTAINING SAMPLES

An alternative method of acid leaching of silicon-containing metallurgical samples using ultrasonic vibrations is proposed in order to extract Si quantitatively from the solid phase into the solution. The effect of ultrasonic vibration, leaching temperature, phase contact time, weight of the sample, particle size, fraction of hydrofluoric acid in the reaction mixture was investigated. The results of laboratory studies showed that acid leaching assisted by ultrasonic vibrations is an efficient, safe and economically profitable way of sample preparation of silicon-containing metallurgical samples.

Development of Extraction Method of Polycyclic Aromatic Hydrocarbons from Sunflower Oil

Polycyclic aromatic hydrocarbons (PAHs) adsorption extraction process from sunflower oil on activated carbon was studied. Specific adsorption values on activated charcoal-xenobiotic system for compounds of benzo(a)anthracene, benzo(a)pyrene, benzo(e)pyrene, chrysene, benzo(b)fluoranthene and their mixtures were investigated. Influence of phase contact time of system, ratio of components on degree of PAHs extraction under isothermal conditions (25 ± 0.01ºC) was studied. Degree of oil purification was controlled by method of high performance liquid chromatography with fluorescence detector (HPLC/FLD). Leaning on patterns found, optimal conditions for purification of raw sunflower oil from PAHs using activated charcoal and obtaining the matrix of sunflower oil proposed.