Colloidal Compounds Research Articles

The Testing Results of ACORGA, LIX Extractants and CR60 Crud Mitigation Reagent Influence during SX-EW Copper Extraction

Research analysis reveals factors influencing third-phase crud formation and composition during metal extraction, including solution composition, solid suspensions, organic compounds, colloidal compounds (e.g., silicic acid), and extractant purity. Compositional analysis of copper-containing sulfuric acid solutions (1.25 g/dm3 copper) identifies principal sulfate-forming components. Copper extraction was studied using extractants LIX 984N, ACORGA M5774, and M5640 at different ratios of the organic phase to the aqueous O:A (from 1:2 to 1:10). Suppressive impact of 10 vol.% CR60 additive on third-phase crud formation during copper extraction with LIX 984N, ACORGA M5774, and M5640 is analyzed, with ACORGA M5774 being the most effective. Physicochemical analysis characterizes CR60’s active substance as poly(sodium 4-styrenesulfonate) with steel-suppression properties, and its structural formula is determined. Optimal copper extraction conditions establish ACORGA M5640’s 24% efficiency, followed by ACORGA M5774 at 15%. CR60 reduces crud formation, with 5 cm3 of ACORGA CR60 added to sulfuric acid solution reducing interfacial crud formation by 2–3 times. Optimal extraction parameters include 1:2 O:A ratio, 20 ± 5 °C temperature, 5 cm3 CR60 additive, 5 min process duration, and 1-day settling time. ACORGA M5774 (10 vol.% in kerosene) is recommended as an extractant, with 2–3 stages of countercurrent extraction.

Building a simple multivariable filtration model to predict irreversible fouling when directly filtering municipal wastewater

This paper describes a simple generic model designed to predict membrane fouling in municipal wastewater (MWW) treatment. The work was conducted using data from a direct membrane filtration demo-system (middle/long-term filtration periods of about 35 – 124 days) to calibrate the model. Two influents were treated by the demo-system: raw pre-treated MWW and primary settler supernatant from a full-scale MWW treatment plant. A resistance-in-series mathematical model structure was proposed considering fouling due to two different mechanisms: persistent cake layer formation (from suspended material) and pore blocking (from soluble and colloidal compounds). The proposed model represented transmembrane pressure dynamics at different operating solids concentrations (around 1, 2.6, 6 and 11 gL−1) using 7 model parameters, achieving 7–28 mbar differences between the experimental data and model predictions in all cases (calculated as the root mean square error). The model was also able to match the results from two different influents (raw MWW and primary settler supernatant) by modifying 3 of the 7 parameters while low uncertainties were obtained in long-term filtrations, demonstrating its robustness. This model thus provides a good potential to generate reasonable membrane fouling predictions while its simple and open structure makes it easy to implement with complementary materials. Further research will be carried out to enhance the model’s precision and validate its potential for optimizing filtration and fouling control processes.

Efektivitas Ferrofluid dalam Penurunan Parameter Limbah Laundri

One of the new applications of ferrofluid, a colloidal compound containing magnetic nanoparticles, is the removal of microplastics from water. Laundry waste has a high concentration of microplastics, but this wastewater contains other substances besides microplastics, such as TSS, COD, surfactants, etc. Therefore, it is necessary to analyze the effectiveness of this method directly from wastewater to determine the total amount. The following is the highest percentage reduction obtained for each parameter: microplastic content of 66.16% is reduced. Then for the TSS parameter, ferrofluid reduces TSS by 70%. As for TDS, the ferrofluid method has the highest percentage reduction of 50.3%. Furthermore, for surfactants or detergents, the highest decrease in ferrofluid was only 10.37%. Lastly, in COD, the biggest decline reached 30%.

Volcanic Soils: Their Characteristics, Management Practices, and Potential Sollution for Water Pollution

Volcanic soils are formed from materials originating from volcanic eruptions, and with various pedogenic processes occurring, volcanic soils have unique physical, chemical, and biological characteristics. This paper aims to review the characteristics of volcanic soils, constraints, management practices, and their potential as adsorbents for contaminants. The paper was based on secondary information using a systematic review. The studies carried out include identifying manuscripts, analyzing report data, critically assessing the topic, and combining the results of relevant published manuscripts. The issues raised include data on volcanic soils, management practices, water pollution, and using volcanic soils as an environmentally friendly adsorbent. Colloidal compounds in the clay fraction of volcanic soils generally contain active Al and Fe compounds, allophane, imogolite, ferrihydrite, or Al/Fe-humus complex, and together with opaline silica. The volcanic soil material produces a pool of Al and Fe solid phases with high reactivity, which contributes to the unique physicochemical properties of Andisol. The main problem chemically is the high adsorption of phosphate and nitrate ions which causes the fertilization process to be inefficient. The main problem affects the adsorption of phosphate and nitrate on agricultural lands, so fertilization becomes inefficient. However, the high reactivity of volcanic soils can be used as a basic pollutant adsorbent. This is quite a promising opportunity, given the wide distribution of volcanic soils, so this resource is a very prospective candidate as an adsorbent material in water purification.

Perovskite-Based Solar Cells: Some Problems and Ways of their Solution

The fundamental aspects of the perovskite absorber formation of solar irradiation for two generally accepted one- and two-step technologies are considered. For the on-step variant, two stages of perovskite formation, called “through solution” and “intermediate colloid compounds of precursors”, were identified. The successive deposition of precursors is described in terms of thermodynamics and the Ostwald ripening model. The optimal conditions for the concentration and temperature for the spinning solution of methylammonium iodide to obtain various sizes of perovskite crystallites are presented. Examples are given for some other approaches that are used in the formation of high-quality perovskite films with high optoelectronic characteristics for a conversion rate of perovskite based solar cells on them.

The use of a composite mix to remove metals from acidic drainage waters at tailings facilities

This paper describes various studies on the possibility of using MSW incineration waste for treating acidic drainage waters at tailings facilities. It has been shown that the required water purity for its recycling into the process is observed when using a composite mix containing MSW incineration waste and quicklime at the ratio of 10 to 1. The kinetics of sedimentation of suspended solids and the resulting colloidal compounds indicates that the acceptable particle concentration is achieved after 2–3 minutes. The expected economic effect of using this composite mix consists in the prevention of the general environmental damage from pollution of the aquatic environment, land, and bioresources with metals, as well as from the impact of waste storage sites during MSW incineration on various components of the natural environment. The settled sludge may then be disposed into the tailings facilities to ensure the storage of respective valuable components for subsequent recovery. The use of MSW incineration waste as part of the composite mix for the treatment of acidic drainage waters at mining enterprises solves a set of urgent problems:— enables environmentally efficient treatment to prevent environmental damage caused by the ingress of acidic drainage waters contaminated with metals into the ground and natural watercourses;— ensures cost-effective use of MSW incineration waste;— reduces the volume of accumulated MSW incineration waste and ensures conservation of natural resources;— enables the storage of valuable components for subsequent recovery through disposal of the settled sludge in the tailings facilities.

Structure of a subnanometer-sized semiconductor Cd14Se13 cluster

Structure of a subnanometer-sized semiconductor Cd14Se13 cluster

Combined iron oxides and gypsum fouling of reverse osmosis membranes during desalination process

Fouling is an inherent challenge in the Reverse Osmosis (RO) desalination process. Inorganic and colloidal compounds are frequently encountered on RO membrane surfaces. Although fouling is the topic of various studies, combined fouling notably by gypsum and iron oxides and their interaction is not yet studied. Therefore, the aim of this work is to study the combined fouling by gypsum and iron oxides and their interaction with the surface of the RO membrane. Gypsum and iron scaling were compared, and it was demonstrated that gypsum scaling caused severe water flux decline and induced membrane wetting. An important flux decline was also observed for iron scaling when the pH of feed solution is close to 6. Flux decline caused by combined fouling was compared with an individual fouling. A membrane fouling trials showed a synergistic effect between the dissolved calcium sulfate and iron oxide particles, which aggravated and accentuated RO the membrane fouling. The drop in normalized flux, caused by the combined fouling, was compared to the two-individual fouling (with gypsum and iron oxides), it appears that the combined one was 50% higher. The molecular interactions between iron oxides and gypsum as well as the properties of the formed crystals were determined by SEM/EDX and X-Ray Diffraction.

A Two-Pathway Model for the Evolution of Colloidal Compound Semiconductor Quantum Dots and Magic-Size Clusters.

A fundamental understanding of formation pathways is critical to the controlled synthesis of colloidal semiconductor nanocrystals. As ultrasmall-size quantum dots (QDs) sometimes emerge in reactions along with magic-size clusters (MSCs), distinguishing their individual pathway of evolution is important, but has proven difficult. To decouple the evolution of QDs and MSCs, an unconventional, selective approach has been developed, along with a two-pathway model that provides a fundamental understanding of production selectivity. For on-demand production of either ultrasmall QDs or MSCs, the key enabler is in how to allow a reaction to proceed in the time prior to nucleation and growth of QDs. In this prenucleation stage, an intermediate compound forms, which is the precursor compound (PC) to the MSC. Here, the two-pathway model and the manipulation of such PCs to synthesize either ultrasmall QDs or binary and ternary MSCs are highlighted. The two-pathway model will assist the development of nucleation theory as well as provide a basis for a mechanism-enabled design and predictive synthesis of functional nanomaterials.

ЗАЩИТА РЕЗЬБОВЫХ СОЕДИНЕНИЙ ОТ ТЕРМООКИСЛИТЕЛЬНОГО СХВАТЫВАНИЯ

Modern industry places a number of stringent requirements to the performance properties of fasteners. All fastening elements made of metal are subject to corrosion-mechanical wear. Their disassembling is a time-consuming process which is often accompanied by destruction of the part. Damage to threaded connections can be prevented by applying a special thread lubricant to the part. Based on theoretical and experimental research, the authors have developed a formulation of high-temperature thread compound “Udar”, which contains the following components: molybdenum disulphide (70 wt.%), titanium dioxide (3 wt.%), colloidal graphite compound (70 wt.%), aluminium (powder) (5 wt.%), OMIK “TELAZ” (10 wt.%), thickener (petrolatum), and industrial oil I-40A. The lubricant efficiency in protecting fasteners against atmospheric corrosion and corrosion setting was tested on six specimens representing a pair of “bolt-nut”. The results of comparative laboratory tests of the developed composition with foreign-made greases have shown that the developed thread lubricant is able to protect threaded joints from thermal-oxidative setting occurring at up to 9000C. Application of this composition will considerably reduce the equipment disassembling time due to reduction of the absolute value of torque when disassembling fasteners, and prevent thermochemical and corrosion “seizure” of threaded joints.

Metallization of colloidal crystals

Colloidal crystals formed by size-asymmetric binary particles coassemble into a wide variety of colloidal compounds with lattices akin to ionic crystals. Recently, a transition from a compound phase with a sublattice of small particles to a metal-like phase in which the small particles are delocalized has been predicted computationally and observed experimentally. In this colloidal metallic phase, the small particles roam the crystal maintaining the integrity of the lattice of large particles, as electrons do in metals. A similar transition also occurs in superionic crystals, termed sublattice melting. Here, we use energetic principles and a generalized molecular dynamics model of a binary system of functionalized nanoparticles to analyze the transition to sublattice delocalization in different coassembled crystal phases as a function of temperature ($T$), number of grafted chains on the small particles, and number ratio between the small and large particles ${n}_{s}:{n}_{l}$. We find that ${n}_{s}:{n}_{l}$ is the primary determinant of crystal type due to energetic interactions and interstitial site filling, while the number of grafted chains per small particle determines the stability of these crystals. We observe first-order sublattice delocalization transitions as $T$ increases, in which the host lattice transforms from low- to high-symmetry crystal structures, including A20 $\ensuremath{\rightarrow}$ bct $\ensuremath{\rightarrow}$ bcc, ${\mathrm{A}}_{\mathrm{d}}$ $\ensuremath{\rightarrow}$ bct $\ensuremath{\rightarrow}$ bcc, and bcc $\ensuremath{\rightarrow}$ bcc/fcc $\ensuremath{\rightarrow}$ fcc transitions and lattices. Analogous sublattice transitions driven primarily by lattice vibrations have been seen in some atomic materials exhibiting an insulator-metal transition also referred to as metallization. We also find minima in the lattice vibrations and diffusion coefficient of small particles as a function of ${n}_{s}:{n}_{l}$, indicating enhanced stability of certain crystal structures for ${n}_{s}:{n}_{l}$ values that form compounds.

Analysis of the Features of the Behavior of Track Membrane Filters during their Use

Changes in the properties of a FiTreM track membrane filter with a 0.45 μm pore diameter during water filtration and changes in filtration rate during continuous water filtration were studied. It was established during the experiments that the decrease in filtration rate through a track membrane filter depends both on the occurrence of suspensions and colloid compounds, as well as on the physical properties of the filter. This is also due to the change in membrane permeability due to partial destruction of a filter, its compaction during use, as well as the accumulation of a negative charge on the pore surface due to the dissociation of COOH groups.

The impact of air pollution on the rate of degradation of the fortress of Florianópolis Island, Brazil

The study of the prevalence of agglomerated nanoparticles (ANPs) containing potentially hazardous elements (PHEs) in the atmosphere is an emerging field of research. As such, the development of effective analytical procedures for the documentation of ANPs in air dust is vital for the evaluation of human health consequences. X-ray powder diffraction (XRD), Raman spectroscopy (RS), Mossbauer spectroscopy (MS) and advanced microscopy (AM) analyses of levels of pollutant concentration have been completed for many years in buildings worldwide. The chemical and mineralogical features of the Fortress of Nossa Senhora da Conceição de Araçatuba in the Brazilian state of Santa Catarina were utilized to catalog the geologic makeup of the structure’s raw materials. Analyses of diverse categories of historical building were developed and performed to show the incidence of normal and anthropogenic compounds with PHEs. These geochemical effects and the subsequent fate and transport of nanoparticulate and colloidal (1–1000 nm) compounds in the atmosphere have remained a focus of study for many years. However, the data published in the scientific literature is nowhere near adequate to generate an exhaustive standard of the performance, fate, and transport of natural and anthropogenic ANPs in the atmosphere. Studies to date do provide a preliminary argument for the human health risk calculations from historical buildings due to ANPs. Thus, the geochemical makeup of ANPs and their position in collected nanomineral–organic accumulations may offer some insight into their source. Our ability to detect such ANPs may decrease over time due to the tendency of historical buildings to accrete sludge over the years. The occurrence of PHEs in atmospheric ANPs has not formerly been recognized on the island environment examined in this study. However, it has been shown that it presents a clear and present danger to the preservation of historical monuments.

Inverse transition of labyrinthine domain patterns in ferroelectric thin films.

Phase separation is a cooperative process, the kinetics of which underpin the orderly morphogenesis of domain patterns on mesoscopic scales1,2. Systems of highly degenerate frozen states may exhibit the rare and counterintuitive inverse-symmetry-breaking phenomenon3. Proposed a century ago4, inverse transitions have been found experimentally in disparate materials, ranging from polymeric and colloidal compounds to high-transition-temperature superconductors, proteins, ultrathin magnetic films, liquid crystals and metallic alloys5,6, with the notable exception of ferroelectric oxides, despite extensive theoretical and experimental work on the latter. Here we show that following a subcritical quench, the non-equilibrium self-assembly of ferroelectric domains in ultrathin films of Pb(Zr0.4Ti0.6)O3 results in a maze, or labyrinthine pattern, featuring meandering stripe domains. Furthermore, upon increasing the temperature, this highly degenerate labyrinthine phase undergoes an inverse transition whereby it transforms into the less-symmetric parallel-stripe domain structure, before the onset of paraelectricity at higher temperatures. We find that this phase sequence can be ascribed to an enhanced entropic contribution of domain walls, and that domain straightening and coarsening is predominantly driven by the relaxation and diffusion of topological defects. Computational modelling and experimental observation of the inverse dipolar transition in BiFeO3 suggest the universality of the phenomenon in ferroelectric oxides. The multitude of self-patterned states and the various topological defects that they embody may be used beyond current domain and domain-wall-based7 technologies by enabling fundamentally new design principles and topologically enhanced functionalities within ferroelectric films.

Study of reverse osmosis membranes fouling by inorganic salts and colloidal particles during seawater desalination

Abstract Fouling phenomenon is considered among the major reasons that cause significant increase of operating cost of desalination plants equipped with reverse osmosis (RO) membranes. This phenomenon is studied in the present work in the case of RO polyamide aromatic membranes using model seawater containing inorganic salts and colloidal compounds. Different solubility conditions of CaCO3 and CaSO4 were applied to study RO performances with and without colloid presence. During experiments, the membrane permeate fluxes were continuously monitored. Moreover, studies of chemical composition, structure, and morphology of the materials deposited on the membrane surface were conducted using energy dispersive microanalysis (EDS) X-ray diffraction and scanning electronic microscopy (SEM). Results show that in conditions of calcium carbonate oversaturation there is a reduction in the permeate flow of 11.2% due to fouling of the membrane by the precipitation of this compound. While in the same conditions of calcium sulphate oversaturation the reduction of the flow is 5%, so we can conclude that in conditions of oversaturation of both salts, calcium carbonate produces a greater fouling of the membrane that in its view causes greater decrease in the flow of permeate. All this based on the results of the test with both salts in oversaturated conditions. Resulting in the formation of calcite and gypsum crystals onto the membranes as XRD analyses stated. Additional presence of colloidal silica in those conditions intensifies strongly the fouling, leading until to 24.1% of permeate flux decrease.

DINAMISASI DAN PRODUKTIVITAS PRIMER SUNGAI CITARUM PROVINSI JAWA BARAT

Monitoring the quality of the river is essentially to know the status of the periodic quality of the river. Good assessment of river water quality should use a combination of physical, chemical and biological parameters. One way that can be done to describe water quality in an area is the primary productivity in the water. Primary productivity is the amount of organic material produced by autotrophic organisms with the help of sunlight. Perifiton as a river microorganism, will provide dissolved oxygen (DO) through photosynthesis to maintain most of the life of the surrounding water, then Periphyton can respond quickly to environmental changes, this is an indicator of changing conditions (Gaiser 2008 and Lakewatch, 2000) in Brown and Wright (2016) Chemical reactions that occur in the aquatic environment also involve interactions between ions and other phases. Some important interactions in the waters are the occurrence of photosynthesis by algae and the exchange of dissolved solids with dissolved gases in water. The same exchange occurs when bacteria degrade organic matter (often in the form of particles) in water. Some important elements move around in aquatic systems as colloidal chemical compounds or are absorbed into soil particles. The equilibrium of physical chemical reactions in waters involves sediment, gas, and water. Sediment is a layer of material or material that covers the bottom of small rivers, lakes, reservoirs, bays, and oceans. Sediments contain fine mixtures and subtle minerals, including clay, silt, and sand, which mix with organic materials. These materials may experience changes in composition from pure mineral ingredients to main organic ingredients. Sediments contain biological ingredients, chemicals, and pollutants in water.
 Keywords: Primary Productivity; citarum river ; sediment; water test parameter

Formation of mineral–mineral and organo–mineral composite building units from microaggregate‐forming materials including microbially produced extracellular polymeric substances

Structures of colloidal compounds in soil, including organo–mineral and mineral–mineral associations, are considered as composite building units (CBUs) that may combine into soil microaggregates. Despite the ubiquitous occurrence of CBUs, the major formation mechanisms are rather obscure and little is known about whether they form primarily during weathering of the parent rocks or by aggregation processes from the soil suspension. We studied the formation of CBUs from suspensions composed of minerals and organic matter typical for temperate soils (i.e. quartz, goethite, illite and extracellular polymeric substances [EPS]). Without EPS, we found CBUs formed as mineral–mineral associations by hetero coagulation of illite and quartz that is bridged by goethite. The presence of EPS, in contrast, led to the formation of a stable suspension of clay‐sized CBUs with no involvement of quartz. We explained this by the rapid formation of organo–mineral CBUs made of EPS‐associated goethite and EPS‐associated illite. The sorption of EPS to goethite screened its surface charge, thereby reducing the electrostatic attraction between goethite and illite. This interaction effectively impeded the formation of mineral–mineral CBUs. Moreover, interactions of EPS with goethite resulted in a marked decrease of the phosphorus/carbon ratio in the suspension. This suggested a preferred adsorption of phosphorus‐containing EPS constituents to goethite and in turn to a compositional fractionation of EPS constituents between the solid and liquid phase as shown by Fourier‐transform infrared spectroscopy with attenuated total reflection (FTIR–ATR). Laser light diffraction measurements revealed a shift from the fine silt fraction to that of the fine sand that also supports the role of EPS as a ‘binding’ agent.Highlights Composite building units (CBUs) form in suspensions with different mineral and organic components. Both, hetero mineral–mineral and organo–mineral CBUs were formed. The initial composition of the suspension controls type and properties of resulting CBUs. Depending on the mineral surfaces, EPS may serve as a separation or binding agent.

УСЛОВИЯ СОВМЕСТНОГО УДАЛЕНИЯ СОЕДИНЕНИЙ КРЕМНИЯ И ГУМИНОВЫХ ВЕЩЕСТВ ИЗ ПРИРОДНЫХ ВОД В ПРИСУТСТВИИ ПРОДУКТОВ ТЕРМИЧЕСКОЙ ОБРАБОТКИ МАГНЕЗИТА

Актуальность. Подземные воды Западно-Сибирского региона характеризуются повышенным содержанием ионов железа, силикат ионов и органических веществ гумусового происхождения. Эти примеси способствуют образованию устойчивой коллоидной системы. При использовании природной воды в качестве теплоносителя на поверхности труб формируются силикатные отложения за счет связывания катионов кальция, магния, алюминия, железа. Совместное присутствие силикатов и органических примесей приводит к снижению эффективности очистки воды с применением существующих технологий водоподготовки. Цель: определение концентрационных и температурных условий образования соединений кремния с гуминовыми веществами и скорости их осаждения в присутствии продуктов термической обработки магнезита (каустического магнезита). Объекты: природные воды и модельные растворы, содержащие соединения кремния и растворенные гуминовые вещества, каустический магнезит. Методы: фотоколориметрия, рН-метрия, титриметрия, атомно-эмиссионная спектрометрия с индуктивно связанной плазмой (ICAP-6000). Результаты. Установлен интервал массовых соотношений растворимых гуминовых веществ и силикатов ГВ:SiO32–=0,8–4, в котором гуминовые вещества и SiO32–-ионы при совместном присутствии в интервале рН=5…9 связываются в органо-минеральные комплексы. В природных высокоцветных водах (содержание органических веществ до 30 мгО/л) до 40 % силикат ионов может быть связано в такие комплексы. Размер образующихся коллоидных частиц составил порядка 200 нм, значение ζ-потенциала составило –38 mV. При использовании каустического магнезита в качестве реагента-осадителя взаимодействие в системе «силикат–гуминовые вещества» протекает в две стадии, определяющие технологическую целесообразность одновременного удаления из воды силикатов и гуминовых веществ.

Cytotoxicity of 5-ALA-conjugated bismuth oxidenanoparticles on KB cell line

Introduction: In recent years, bismuth-based nanomaterials have been widely used in medical researches as imaging, drug delivery and x-ray radiosensitizing agents. Due to their anti-microbial effects against Helicobacter pylori (HP), bismuth colloidal compounds are used to treat various types of diseases such as chronic gastritis. Despite their advantages, bismuth-based compounds have shown many toxic effects in humans. There are few studies on cytotoxicity effects of bismuth (ΙΙΙ) oxide (Bi2O3) nanoparticles (NPs). Based on the natural high affinity of folate for the folate receptor protein (FR), which is commonly expressed on the surface of many human cancers, folate-drug conjugates bind tightly to the FR and trigger cellular uptake via endocytosis. Therefore, we aimed to investigate the cytotoxicity effects of 5-ALA-conjugated Bi2O3 NPs, 5-ALA-folate-conjugated Bi2O3 NPs and free 5-ALA on oral squamous carcinoma cell line (KB cells) for the first time. 5-ALA is used in photo dynamic detection and photodynamic surgery of cancer. Being a precursor of a photosensitizer, 5-ALA is also used as an add on agent for photodynamic therapy. Materials and Methods: Bi2O3 NPs were synthesized and conjugated with folate and 5- aminolevulinic acid (5-ALA). KB cells were cultured monolayer and incubated with 10, 20, 50, 100 and 200 μg/ml concentrations of free 5-ALA, 5-ALA-folate-conjugated Bi2O3 NPs and 5-ALA-conjugated Bi2O3 NPs for 24 hours. The survival of the cells obtained after 24 h of incubation with the materials using MTT assay. Results: Bi2O3 NPs were synthesized (~20 nm) and conjugated to folate and (5-ALA). Results indicated that the significant cellular death were noted at the concentrations more than of 50 μg/ml for all compounds that cell viability reduced to 37%, 49% and 63% in groups receiving 5-ALA-folate-conjugated NPs, 5-ALA-conjugated Bi2O3 NPs and free 5-ALA, respectively. The cytotoxicity of the materials on KB cells also increased with increasing concentrations of synthesized NPs. Conclusion:5-ALA-folate-conjugated NPs, 5-ALA-conjugated Bi2O3 NPs and free 5-ALA were easily taken up by the cells and showed cytotoxic effects at high concentrations. Folic acid conjugation facilitates selective targeting of the KB cells with the overexpression of the folate receptors and improves internalization of the drugs through receptor-mediated endocytosis

Wastewater treatment from heavy metals using extracts of wood processing waste (oak bark)

The paper considers the issues of using extracts from wood processing industry waste (oak bark) for wastewater treatment from heavy metal ions (Cr+6) are considered. The principle of purification is the formation of aggregates, formed by the contact of organic colloidal compounds (tannins) with positively charged heavy metal ions. It is established that the maximum formation of a precipitate is observed in acid media (pH = 2.5). This is due to the fact that during the oxidation of the substance the compounds of hexavalent chromium pass to the salts of trivalent chromium, which forms a precipitate. To improve the efficiency of treatment, oak bark was crushed on a shredder and a hammer mill with the subsequent production of an alkaline extract.