Analysis of the efficiency of industrial water purification from heavy metals with a carbon-containing sorbent

The article presents the results of determining the efficiency of removing heavy metals from industrial wastewater by the sorption method using the “charge”, which is a waste of a coal mining enterprise, as well as activated carbon. Also, in addition to experimental data, the research material contains photographic materials of the sorbent surface and the result of its X-ray spectroscopy.

Obtaining and research of aluminosilicate sorbent

A technological scheme for the synthesis of an aluminosilicate sorbent in laboratory conditions using clay from the Semilukskoye deposit has been developed. When the sorbent sample is heated in the range of 30-225 ° C, a loss of free moisture occurs, in the temperature range of 405-550 ° C, bound water begins to evaporate and decomposition of organic substances occurs. The sorption of sodium sulfide by the sorbent surface has been studied. The constants ? and n are determined in the Freundlich equation A = 1.38 ? C1.19. Formed specific surface area S = 12.8 m2 / g. A comparative study of the acid-base properties of the surface of the synthesized aluminosilicate sorbent and diatomite Celite 545 60/80 MESH by the indicator method has been carried out. The adsorption on the acid-base centers of the synthesized aluminosilicate sorbent surface is higher than the adsorption on the diatomite surface. On the surface of the synthesized aluminosilicate sorbent, there are both acidic (pK = 1.7; 3.46) and basic (pK = 18.8; 9.2) Bronsted centers The pore volume of the synthesized aluminosilicate sorbent corresponds to 0.25 cm3 / g. This value is less than the pore volume of diatomite 1.86 cm3 / g.

Silver-coated monolitic silica column for separation of benzo[a]pyrene from petroleum

Monolithic silica solid-phase extraction column has been successfully applied for the rapid fractionation and subsequent gas chromatographic analysis of benzo[a]pyrene from the diesel and oil matrix. Due to π-π electronic interactions between silver nanoparticles on the sorbent surface and aromatic analyte specific retention was achieved. It was demonstrated that only 0.2 g of the sorbent and 6 ml of the organic solvent are enough for such separation.

Design and Properties of Magnetically Controlled Sorbents

In this work, the main parameters and advantages of magnetically controlled sorbents are considered. A large surface of nanodispersed magnetically controlled sorbents adsorbs large amounts of toxins, therefore, the consumption of magnetically controlled sorbents in each operation is insignificant. The ability to quickly replace the spent magnetically controlled sorbents in the detoxification apparatus with a new portion of magnetically controlled sorbents increases the reliability, simplicity and ease of use of the method under consideration. The small thickness of the sorbent layer and the availability of the sorbent surface provide almost instantaneous establishment of equilibrium concentrations, which significantly reduces the required processing time for the biofluid and increases the productivity of the purification process.

Studying electric double layer under sorption of gold on activated carbons from thiocarbamide solutions

The purpose of the article is to research the mechanism of gold-thiocarbamide complex sorption by activated carbons by studying the properties of the resulting electric double layer. The study of the electric double layer of coal sorption surface is conducted using a polar conductometric method based on the simultaneous use of polarization dependences on direct current and conductometric measurements on alternating current. It is shown that the sorption of thiocarbamide complexes of gold occurs more intensively at the cathodic values of sorbent potentials. Dependence of the adsorption value on the potential is actually linear in the negative region from 0.05 to 0.2 V. The absolute value of goldthiocarbamide sorption at the negative sorbent potential of 0.2 V coincides with the maximum values of the polarization current for direct current and conductivity for alternating current. The electrochemical reduction reaction of thiocarbamide compounds results in the formation of neutral thiocarbamide molecules, it might be the reason for gold deposition in a metallic form on the surface of the carbon sorbent. Neutralization of active compounds in the electric double layer creates conditions for the activation of positively charged gold ions directing to the negatively charged sorbent surface. The anodic region of sorbent polarization is characterized by the maximum values of gold ion sorption at the positive potential of 0.2 V. In this case the sorbent surface should be recharged, since in the same region of the potential the maximum AC conductivity is observed. Such conditions should lead to the destruction of the thick part of the electric double layer and, consequently, create favorable sorption conditions. The conducted studies allowed to derive a conclusion that the sor ption of gold-thiocarbamide complexes by activated carbons is significantly influenced by the sorbent potential. The use of the polar conductometric method for studying the electric double layer makes it possible to explain the features of given compound sorption on activated carbons.

Separation of Rhodamine B Dye from Aqueous Media Using Natural Pomegranate Peels

Natural pomegranate peels (PPs) ground powder was proved as effective natural biomass for the separation of RhB from different aqueous media by batch adsorption experiments. Several parameters that affect the maximum adsorption capacity toward RhB dye, e.g., the pH solution, initial dye concentration, adsorbent dosage, shaking time, and solution temperature in the sorption behavior, were studied. Adsorption of RhB dye from aqueous media of pH ≈ 5 reached equilibrium in 10 min and was independent of the initial concentration of RhB. RhB dye sorption followed pseudo-second order kinetic with an overall rate constant (k2) of 0.04 g mg–1 min–1. Furthermore, the sorption isotherm was found 31.95 ± 0.02 mg g–1 for the sorption capacity of RhB onto PPs. The thermodynamic parameters (ΔH, ΔS, and ΔG) of RhB retention by the sorbent were calculated. The positive value of ΔH confirms the endothermic behavior of the adsorption of RhB by PPs from aqueous solution. The positive value of entropy (ΔS = 42.17 J mol–1 K–1) of the sorption of RhB onto the sorbent surface may be attributed to the increase in the degree of freedom of the RhB molecules is more restricted in the PPs structure than in solution.