Novel and highly efficient functionalized bentonite for elimination of Cu2+ and Cd2+ from aqueous wastes

The aim of this study was to synthesize novel and highly efficient functionalized material (BNMPTS) for selective elimination of Cu²⁺ and Cd²⁺ from aqueous waste. The detailed insights of solid/solution interactions were investigated by X-Ray photoelectron spectroscopic analyses. The grafting of silane caused for significant decrease in specific surface area of bentonite from 41.14 to 4.65 m²/g. The functionalized material possessed significantly high sorption capacity (12.59 mg/g for Cu²⁺ and 13.19 mg/g for Cd²⁺) and selectivity for these cations. The material showed very high elimination efficiency at a wide range of pH ~2.0 to 7.0 for Cu²⁺, ~3.0 to 10.0 for Cd²⁺ and concentration (1.0 to 25.0 mg/L) for Cu²⁺ and Cd²⁺. A rapid uptake of these two cations achieved an apparent equilibrium within 60 minutes of contact. The increased level of background electrolyte concentrations (0.0001 to 0.1 mol/L) did not affect the elimination efficiency of these two cations by BNMPTS. Moreover, the common coexisting ions did not inhibit the removal of these toxic ions. Furthermore, high breakthrough volumes i.e., 1.4 and 3.69 L for Cu²⁺, 2.6 and 6.64 L for Cd²⁺ was obtained using 0.25 and 0.50 g of BNMPTS respectively in a fixed-bed column operations.

Eco-Friendly Ferrimagnetic-Humic Acid Nanocomposites as Superior Magnetic Adsorbents

Recyclable, cheap, eco-friendly, and efficient adsorbent materials are very important for the removal of pollution. In this work, we report the design and implementation of ferrimagnetic-humic acid nanocomposites as superior magnetic adsorbent for heavy metals. Ferrimagnetic and ferrimagnetic-humic acid nanocomposite particles with different morphologies were prepared using the coprecipitation method and hydrothermal synthesis method, respectively. The results show that the morphology of the nanoparticles prepared by the coprecipitation method is more uniform and the size is smaller than that by the hydrothermal synthesis method. Adsorption experiments show that the ferrimagnetic-humic acid nanoparticles prepared by the coprecipitation method has high sorption capacity for cadmium, and the maximum adsorption capacity is about 763 μg/g. At the same time, magnetic technology can be used to realize the recycling of ferrimagnetic-humic acid adsorbents.

The development of a method for obtaining strontium-based metal-organic framework materials applicable in bionanotechnology

The work proposes a solvothermal method for obtaining metal-organic framework structures (MOF) based on strontium formate, which have a high sorption capacity and an actively developed porous surface. The effect of the ratio of zinc nitrate to formic acid precursors on the structure, shape and size of MOF has been studied — these properties make it possible to use MOF for biomedical purposes. In addition, studies were carried out to determine the antibacterial properties of the obtained MOF.

Physical and Chemical Study of the Structure and Activity of Biopolymer Matrices Based on a Complex of Redox Enzymes

The paper presents experimental results on an effective method of using a complex of redox enzymes of the oxidoreductase class: glucooxidase (CF 1.1.3.4) and peroxidase (CF 1.11.1.7). Literature data confirming an increase in the potential of the redox reaction with the additional introduction of peroxidase, which decomposes hydrogen peroxide during the reaction used in the production of biofuel elements, are presented. The enzyme complex was included in polymer matrices of polyvinylpyrrolidone and acetylcellulose, which have a large number of functional groups, such as amide, hydroxyl, and carboxyl, capable of forming strong covalent bonds with enzymes, as well as a high sorption capacity to proteins. The paper presents a comparative characteristic of the activities of biopolymer complexes. The data of the Fourier-IR spectroscopy prove the formation of strong covalent bonds between the functional groups of enzymes and the matrix used.

Sorption Properties of Thermal Insulation Composed of Flax or Hemp Fibers

This paper deals with the sorption characteristics of thermal insulation materials based on flax and hemp. The added value of these materials is a positive impact on healthy and sustainable housing. Flax and hemp, which are classified as organic, have a high sorption capacity. Changes in the properties of these materials at a relative air humidity of 20% – 95% allow us to determine their advantages and disadvantages as well as whether the insulation is suitable for incorporation into a building structure. The article describes an experiment during which hygroscopic and thermal-technical properties were monitored. The most important indicators were the change in the coefficient of thermal conductivity and the change in the equilibrium moisture content.

Prospects for the application of lignin containing sorbents in veterinary medicine

Vaccines against colibacillosis are mainly used, containing only one specific variant of pathogenic E. coli with a preventive purpose among the livestock of stationary dysfunctional farms in conditions of Krasnoyarsk region. For therapeutic purposes, veterinarians usually use wide range of antimicrobial preparations to combat outbreaks of gastrointestinal infections. Many researchers point to the high variability of E. coli bacteria. Use of such preparations, in addition to the formation of high resistance in opportunistic microorganisms to the latter, provoke the accumulation of antibacterial drugs in animal products. Authors conducted studies of the possibility of the practical use of lignin-containing sorbents for therapeutic and prophylactic purposes in field of veterinary medicine in the period from 2001 to 2020. Authors proposed to use the residues after extraction, formed during the complex processing of larch bark, as an enterosorbent. Authors studied the therapeutic and prophylactic effect of enterosorbent from larch bark in case of gastrointestinal infections in experiments in vivo. It was found that the use of the sorbent for therapeutic purposes for 2 days ensured the safety of laboratory animals in the acute form of colibacillosis infection. Preservation was ensured by preventing the penetration of microbial toxins into the tissues of the gastrointestinal tract. The prophylactic and therapeutic efficacy of the investigated type of enterosorbent is associated with angioprotective, antitoxic effects due to the high sorption capacity of the drugs.

Carbon nanomaterials based on plant biopolymers as radionuclides sorbent

The technogenic human activities associated with the operation of nuclear power facilities lead to the contamination of natural water bodies and soils with radioactive substances, including heavy radionuclides, such as uranium and thorium. Purification of natural water bodies is a pressing environmental issue. A study of the adsorption capacity for heavy U238 and Th232 radionuclides by the samples of new carbon nanomaterials was conducted. Nanocarbon materials was synthesized based on vegetal polymers, such as technical lignin, starch and from lignocellulosic material—the bark. It was established that the investigated samples have different sorption indices in relation to radionuclides, which is determined by their chemical composition, as well as by the surface-capillary properties of carbonized materials. It is shown that the content of mobile and fixed forms of radionuclides on the investigated sorbents are significantly different. High sorption capacity of the carbonated lignin sample with respect to uranium are shown. A sample of nanocarbon materials synthesized based on the lignocellulosic complex of the bark exhibits high sorption properties in relation to thorium. The possibility of using the carbonic nanomaterial as the sorbents of radionuclides is shown.

The efficiency of a flocculent consisting of saw dust and bentonite clay in the removal of Fe and Ni from AMD

Sets of experiments were conducted by pouring 200 mL of synthetic acid mine drainage (AMD) into five 500 mL glass beakers, dosed with varying quantities of bentonite clay and saw dust interchangeably, mixed at 250 and 100 rpm for 2 and 10 mns respectively. The samples settled for 1 hour after which the pH, concentration, oxidation reduction potential (ORP) and percentage removal of heavy metals were measured. The results show that the removal efficiency of a flocculent on Ni and Fe is effective. The results show that saw dust does not affect the conductivity of a solution. The ORP of the samples with a flocculent with increasing bentonite clay exhibits a higher rate oxidation than that of a flocculent with increasing saw dust. The crystal morphology of the SEM micrographs with 1.5 g bentonite clay and 1.5 g saw dust show three types of structures, i.e. round flocs, elongated and clustered agglomerates which is indicative of high sorption capacity.