Concentrations Of Organic Compounds Research Articles

Reactivity of hydrogen sulfide toward organic compounds with sulfur-sulfur bonds

The presence of organic molecules containing sulfur-sulfur bonds was documented in the water columns and sediments of the natural aquatic systems as well as in fossil fuels. These compounds range from small molecules of volatile organic compounds to polysulfide cross-linked macromolecules in the sediments. While processes leading to formation of these compounds were intensively studied during the last decades, kinetics and mechanisms of reactions which lead to their decomposition are poorly understood. In this work, the kinetics and products of the reactions of dimethyl disulfide, dimethyl trisulfide, and cyclic polysulfide lenthionine (1,2,3,5,6-pentathiepane) with hydrogen sulfide at the environmental pH and temperature ranges were studied. It was shown that at pH ≥ 5, the reaction of bisulfide anion (HS–) rather than that of hydrogen sulfide controls the overall reaction rates. The activation energy and the order of the reaction with respect to bisulfide anion is dimethyl disulfide– < dimethyl trisulfide < lenthionine, while the order of the reaction with respect to organosulfur compounds is lenthionine < dimethyl trisulfide < dimethyl disulfide. The obtained results suggest that bisulfide anion is responsible for fast decomposition of organosulfur compounds in aphotic natural aquatic systems. This observation leads to the conclusion that sulfurization of sedimentary organic matter during the early diagenesis is not an unidirectional but a dynamic process, and concentrations of organic compounds with sulfur-sulfur bonds are controlled by the polysulfide to sulfide sulfur concentrations ratio in the sedimentary pore waters. In addition, the cyclic polysulfides were shown to be more stable than their linear analogs that results in preferential preservation of these compounds during the maturation process.

Process-specific volatile organic compounds emission characteristics, environmental impact and health risk assessments of the petrochemical industry in the Beijing-Tianjin-Hebei region.

Volatile organic compounds (VOCs) concentration, source profiles, O3 and SOA formation, and health risks were investigated in the petrochemical industry in Beijing-Tianjin-Hebei. The results showed that total VOCs concentrations were 547.1-1956.5μg·m-3, and alkanes were the most abundant group in all processes (31.4%-54.6%), followed by alkenes (20.6%-29.2%) and aromatics (10.1%-25.1%). Moreover, ethylene (11.3%), iso-pentane (7.1%), n-hexane (5.1%), benzene (4.9%) and 2,2-dimethylbutae (4.8%) were identified as the top five species released for the whole petrochemical industry. The coefficient of divergence between the source profiles from different processes was 0.49-0.73, indicating that most source profiles must not be similar. Moreover, because of the different raw materials and technologies used, the source profiles in this study are significantly different from those of other regions. The ozone and secondary organic aerosol formation potentials (OFPs and SOAPs) were evaluated, suggesting that ethylene, propylene, 1-butene, m,p-xylene, and 1,3-butadiene should be preferentially controlled to reduce OFPs. That benzene, toluene, ethylbenzene, m,p-xylene, isopropylbenzene, o-ethyltoluene, and 1,3,5-trimethylbenzene should be priority control compounds for SOAPs. Additionally, the total hazard ratio for non-cancer risk ranged from 0.9 to 7.7, and only living area was unlikely to be related to adverse health effects. Cancer risks associated with organic chemicals, rubber synthesis, oil refining, and wastewater collection and treatment have definite risks, whereas other processes have probable risks. This study provides a scientific basis for VOCs emission control and management and guides human health in the petrochemical industry.

Concentration and health risk assessment of volatile organic compounds from a closed solid waste landfill site: The role of flaring system

Volatile organic compounds (VOCs) are emitted from landfills, posing health risks to landfill workers as well as nearby residents. This study aimed to assess the health risks associated with the Kuchino landfill near Moscow. The site was closed in 2017, and currently, reclamation and rehabilitation activities are underway by extracting the landfill gases and flaring them.The concentrations of VOCs were measured at the landfill site before flaring and at the edge of the nearby residential area after flaring. The measurements were performed by an accredited laboratory on a quarterly basis during 2020, adhering to relevant Russian and international standards. Measurements were conducted once each during the four seasons. Thirty VOCs were identified at the site and 20 at the nearby residential area. Risk calculations revealed that the workers at the landfill site were exposed to high carcinogenic (1.7 × 10−1) and non-carcinogenic risks (1.1 × 103). Carbon tetrachloride was the main contributor to both carcinogenic and non-carcinogenic risks, with 73.5% and 61% contributions, respectively. Regarding the health risks posed to the residents after flaring, the VOCs were found to exceed the acceptable limit for carcinogens (1.13 × 10−4) and remain within acceptable limits for non-carcinogens (9.23 × 10−1). Chloroform contributed 80% to potential carcinogenic risks and xylene contributed 57% to non-carcinogenic risks—both were principal contributors in their respective categories. The findings suggest the need for urgent mitigation actions to protect the health of workers and residents. Flaring is not a magical solution for VOCs emission; rather, flaring itself produces certain harmful VOCs.

Intensification of processes of biological wastewater treatment

Purification of urban wastewater traditionally takes place at biological treatment plants, which were built in the 60s and 70s of the last century and are still being operated in populated areas of Ukraine. Today's wastewater contains high concentrations of surfactants, organic compounds, biogenic substances and other pollutants from enterprises that exceed the permissible concentrations at the entrance to treatment plants, which leads to ineffective treatment in traditional biological treatment schemes. It was this fact that became one of the main reasons for exceeding concentrations of nitrogen and phosphorus compounds in water sources. Therefore, in order to intensify wastewater treatment, it is necessary to choose more effective methods of wastewater treatment and to design structures that will ensure their proper treatment. The work considers the microbiological processes that will take place in the proposed design of the bioreactor.

Exploration of 5-Azacytidine and Trichostatin A in the modulation of postharvest quality of 'Shine Muscat' grape berries

Grapes have excellent commercial characteristics and high nutritional value, but postharvest storage inevitably reduces their quality. Previously, we studied the regulatory mechanisms of methylation for grape ripening. To further investigate the effects of epigenetic modifications on postharvest quality of grape berries, Transcriptome deep sequencing (RNA-seq) and metabolome sequencing were performed on 5-Azacytidine (5azaC) or Trichostatin A (TSA) treated grape berries. TSA delayed the depletion of soluble sugar and organic acid content in postharvest grapes compared to controls, while 5azaC had the opposite effect. In addition, TSA and 5azaC affected the content and composition of volatile organic compounds (VOCs) in the berries, of which the decrease in linalool content may be directly responsible for the reduction of muscat flavor in the berries. RNA-Seq analysis showed that 626 and 2253 differentially expressed genes (DEGs) were generated by 5azaC and TSA treatments, respectively. GO and KEGG enrichment analyses revealed significant differences in the biological pathways involved in the two collections of DEGs. Metabolomic analyses further clarified the marker metabolites induced by TSA and 5azaC related to fruit quality. In addition, the results of HDAC activity and transcript levels of acetylation-related genes suggest that VvHDA15 may acetylation modification affects the key regulators of postharvest fruit quality. This study not only provides abundant data information, but also offers new insights into the regulation of fruit quality by epimodification.

Utilization of Spent Coffee Grounds as a Sustainable Resource for the Synthesis of Bioplastic Composites with Polylactic Acid, Starch, and Sucrose

Polylactic Acid (PLA) is a biodegradable polymer, but the cost of PLA is not competitive compared to polyolefins. The development of bioplastic composites by blending PLA with spent coffee grounds (SCG) and thermoplastic starch (TPS) is an effective way to reduce the cost of PLA. This study aimed to investigate and evaluate the feasibility of using SCG to develop bioplastic composite materials with a blend of PLA and TPS. Bioplastics were fabricated with various SCG contents (5, 10, 15 wt%). The physical and mechanical characteristics of the bioplastic composite decreased as the SCG content increased owing to the higher aggregation caused by SCG dust. However, the bioplastics manufactured with the addition of SCG exhibited enhanced crystallinity, resulting in enhanced thermal properties compared to the composites without SCG. The best characteristics of bioplastics, obtained with a 5% SCG addition, were as follows: water vapor transmission rate of 1276 g d/m2, water vapor permeability (WVP) of 1.86256 × 10−7 g/ms Pa, Young’s modulus of 420 MPa, elongation of 2.59%, and tensile strength of 5 MPa. Based on the results obtained, it can be concluded that the addition of SCG is not recommended for improving the physical and mechanical properties of bioplastics. However, owing to its large content of organic compounds, SCG represents a promising and low-cost functional material that can be exploited in the development of various value-added products.

Efficient degradation of soybean protein B3 subunit in soy sauce by ultrasound-assisted prolyl endopeptidase and its primary mechanism.

Prolyl endopeptidase can partially degrade soybean protein B3 subunit and alleviate soy sauce secondary precipitate. In this study, the influences of ultrasound-assisted prolyl endopeptidase on the degradation of soybean protein B3 subunit of soy sauce and primary mechanism were investigated using SDS-PAGE, MALDI-TOF-MS, circular dichromatic spectrometer, fluorescence spectra, etc. Results showed that ultrasound-assisted prolyl endopeptidase enhanced 72% degradation rate of B3 subunit and reduced soy sauce secondary precipitate remarkably, meanwhile significantly increased content of organic taste compounds of soy sauce compared with control (p<0.05). Sonication markedly reduced percentage of α-helix and increased percentage of random coil, made hydrophobic amino acids inside prolyl endopeptidase exposed to its surface and enhanced its flexibility, which facilitated the binding of prolyl endopeptidase active center with B3 subunit and finally enhanced the latter's degradation rate and appearance quality of soy sauce. This work laid a foundation for solving soy sauce secondary precipitate.

A Comprehensive Study of Variation in Water Quality Parameters to Design a Sustainable Treatment Plant

In this paper, greywater samples are collected from the kitchens of different types of buildings (residential and commercial) located in different districts within the city of Jeddah, Saudi Arabia. The collected samples are analyzed and compared with the potable water from the same region. The parameters investigated are pH, conductivity, total solids (TS), total dissolved solids (TDS), total suspended solids (TSS), total hardness, temporary hardness, permanent hardness, alkalinity, chloride, and biochemical oxygen demand (BOD). It was found that the amount of total suspended solids is very high in the greywater samples. It shows the presence of both temporary and permanent hardness. Their alkalinity values are greater than hardness. It may be due to the number, lifestyle, age of the occupants, presence of children, and social and cultural behavior of residents. The concentration of BOD level is very low, which shows that the greywater samples have lower concentrations of organic compounds. Design details of the greywater treatment plant are suggested based on the results of the analysis. This includes a screening chamber, grit chamber, settling tank, and filtration unit. The treated greywater is recommended for reuse for gardening, landscaping, and toilet flushing purposes.

Effect of wastewater temperature and concentration of organic compounds on the efficiency of ammonium nitrogen removal in a household treatment plant servicing a school building

Effect of wastewater temperature and concentration of organic compounds on the efficiency of ammonium nitrogen removal in a household treatment plant servicing a school building

Correlations between organic pollution indicators in municipal wastewater

The paper presents the results of a study of parameters used for determining the amount of organic pollutants in wastewater flowing into a collective wastewater treatment plant with a population equivalent of about 120 000 PE. The plant constituted part of a sewage system. Assays were performed for biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), permanganete index (CODMn) and total organic carbon (TOC). In addition, the pH of wastewater and its alkalinity were determined. Sampling of incoming wastewater and measurement of physicochemical parameters were performed once a week, in the spring. A total of 44 samples of wastewater were collected. The correlations between the individual parameters and the correlations between the ratios of these parameters were determined. It was found that it was possible to estimate, with suffi cient accuracy, the values of selected parameters for determining the concentrations of organic compounds in municipal wastewater, knowing the values of other parameters in this group. Moreover, it was shown that, knowing the relationship between the analyzed parameters, one can find multiple regression equations for a given type of wastewater, which allow one to calculate the remaining relationships with a good fit, i.e. a determination factor R2greater than 0.6

Changes in biodiversity impact atmospheric chemistry and climate through plant volatiles and particles

Climate extremes in tandem with biodiversity change affect plant emissions of biogenic volatile organic compounds, as a result, the formation of biogenic secondary organic aerosols. The resulting biogenic secondary organic aerosols can have a wide variety of impacts, such as on Earth’s radiative balance or cloud- and precipitation formation. However, at present, it is unclear how changing biodiversity will lead to changes in biogenic volatile organic compound emissions, biogenic secondary organic aerosols and their corresponding effects. We present a conceptual framework of the relationships between biodiversity and biogenic volatile organic compound emissions based on our current mechanistic understanding and combining knowledge from the fields of biology and atmospheric chemistry. Parts of this framework are tested in a case study using a tree diversity experiment. The relative differences in tree monocultures and mixtures show that the overall concentration of biogenic volatile organic compounds decreases with increasing biodiversity, but results for biogenic secondary organic aerosols are mixed and overall non-significant. A deeper understanding of how changing biodiversity influences biogenic organic compound emissions and biogenic secondary organic aerosol formation requires in-depth investigations of microclimate conditions, accurate monitoring of above- and below-ground biotic and abiotic stress, and manipulating stress conditions across long-term biodiversity experiments.

Phthalate Concentration Estimation and Exposure Assessment and Health Risk Assessment in Indoor Organic Film

Organic films act as passive air samplers and can be employed to assess the concentration of semivolatile organic compounds (SVOCs), such as phthalates, in the gas phase over a defined period using the kinetic adsorption model. Consequently, indoor organic films have been identified as effective media for evaluating human exposure to SVOCs. This study proposed an organic film-based method for assessing SVOC exposure in the indoor environment. Exposure assessments of various phthalate pathways were conducted on children and adults. Organic films were collected for analysis from 110 residential dwellings in metropolitan areas over a two-month period. The exposure assessments were categorized into inhalation, oral, and dermal exposure pathways. Diethyl phthalate was highest in inhalation exposure, dibutyl phthalate represented the highest dermal exposure, and bis(2-ethylhexyl) phthalate was identified as the highest contributor to oral exposure. For children, the primary exposure pathways included dermal absorption of DBP, DEP, diisobutyl phthalate (DiBP), butylbenzyl phthalate (BBP), and di-n-hexyl phthalate (DNHP); dust ingestion of DEHP and di-n-octyl phthalate (DNOP); and inhalation of dimethyl phthalate (DMP). The ECR and HQ for inhalation, dermal, and ingestion did not exceed the threshold in children and adults at all pollutants, suggesting no potential health impact. In contrast, the primary routes of exposure for adults were dermal absorption of DBP, DMP, DEP, DiBP, BBP, and DNHP, along with dust ingestion of DEHP and DNOP. The findings of this study provide valuable baseline data for future research in health risk and SVOC exposure assessments utilizing indoor organic films.

Volatile organic compounds produced by some synthetic essential oils as biological fumigants against Botrytis cinerea on apples

BackgroundGray mold, attributed to Botrytis cinerea, poses a substantial threat to food security in fruit-growing regions impacted by global climate change. Addressing this disease requires the utilization of either resilient plant varieties or advanced technological interventions. In this study, the research focused on examining the volatile organic compounds (VOCs) emitted by synthetic essential oils, namely thymol, eugenol, 1,8-cineol, and their combination, as potential biological fumigants against B. cinerea on Golden Delicious apples.ResultsIn this study, a total of 53 compounds were identified and categorized into six distinct classes, which included (1) terpenes, (2) esters, (3) C6 compounds, (4) alcohols, (5) acids, and (6) aldehydes. The results we obtained revealed significant variations in the volatile compounds present in apples after harvest when treated with different essential oils to combat B. cinerea. Among the VOCs found in the fruits, the most abundant ones were pentanal, nerol, and ethyl octanoate. The essential oil combination of thymol, eugenol, and 1,8-cineol (Thy + Eug + Fun) had the most significant impact on the volatile compound content in the fruits. Conversely, both B. cinerea and the essential oils were observed to increase the volatile organic compound content in the fruits after harvest.ConclusionThe findings from this study underscore the significance of essential oils as effective biological fumigants for countering Botrytis cinerea on apples. Furthermore, the study suggests that these essential oils have the potential to influence the composition of volatile organic compounds in postharvest apples. This research offers valuable insights into the intricate interplay between volatile organic compounds and essential oils in apples, emphasizing the critical role of essential oils in preserving fruit quality during the post-harvest period.Graphical abstract

Applying S(IV)-Fe(II) binary activation of permanganate as ultrafiltration pretreatment for fouling mitigation: Performance, influencing factors, and mechanism

The widespread implementation of ultrafiltration (UF) technology, which has gained popularity for drinking water treatment, has been impeded by rising operational costs and shortened membrane lifespans resulting from membrane fouling. Here, an integrated pretreatment technique combining oxidation, adsorption, and coagulation was developed using the S(IV)–Fe(II) binary activated permanganate (PM) system, S(IV)–Fe(II)/PM. The efficacy of S(IV)–Fe(II)/PM pretreatment in mitigating UF membrane fouling was investigated for various raw water sources, including lakes, rivers, and seawater. The operational parameters of S(IV)–Fe(II)/PM pretreatment were optimized, and the underlying mechanisms for fouling alleviation were explored. Relative to conventional pretreatment methods, S(IV)–Fe(II)/PM pretreatment reduced reversible fouling-induced resistance by 13%–92% and irreversible fouling-induced resistance by 11%–86%. The S(IV)–Fe(II)/PM system exhibited optimal mitigation of membrane fouling at a PM:S(IV):Fe(II) dosage ratio of 2:3:3, with Grapid × Trapid = 45948, Gslow × Tslow = 12480, and a settling time of 30 min (where G is the velocity gradient and T is contact time). The effectiveness of S(IV)–Fe(II)/PM pretreatment in controlling UF membrane fouling can be attributed to the following mechanisms: 1) modification of feed water quality in terms of organic compound characteristics and concentration, colloidal particle quantity and size distribution, and microbial activity and quantity; and 2) adjustment of the membrane surface deposition environment, resulting in reduced polysaccharide and protein content, particle size distribution range, and biomass, as well as alterations in physicochemical properties such as hydrophilicity and interfacial free energy. This study highlights the efficacy of S(IV)–Fe(II)/PM pretreatment in ensuring high-quality UF effluent while effectively reducing membrane fouling, especially its potential for alleviating irreversible membrane fouling.

Ultrasound assisted TiO2@Fe3O4 nanocomposites photocatalytic degradation of organic pollutants in potato starch processing wastewater

Potato starch industrial wastewater should be treated and discharged after optimization due to the high concentration of organic compounds and heavy pollution load. In this study, Fe3O4 nanoparticles were synthesized by co-precipitation technology, and the TiO2@Fe3O4 nanocomposites were synthesized by ultrasonic chemistry method. The structure and morphology of the nanocomposites were characterized, and the degradation of organic pollutants in potato wastewater by TiO2@Fe3O4 nanocomposites under light conditions were investigated. The results show that TiO2@Fe3O4 nanocomposites can be used to catalyze the degradation of organic pollutants in potato starch industrial wastewater under visible light. Under the optimal conditions, the degradation rates of COD, TOC and TN of potato starch processing wastewater reached 73.60 %, 48.21 % and 14.54 %, and after ultrasonic pretreatment, the degradation rates of COD, TOC and TN of potato wastewater were significantly increased to 82.34 %, 63.63 % and 24.17 %, respectively. This method provides a feasible and efficient purification way for the degradation of organic pollutants in potato starch processing wastewater. The degradation mechanism was discussed through free radical scavenger test. It was found that HO· and H· played a major role in the degradation.

Changes in total volatile organic compound concentration in Seoul subway stations before (2019) and after (2021) the COVID-19 outbreak

Volatile organic compounds (VOCs) are major air pollutants often designated as specific hazardous or toxic. This study analyzed the trends in concentration changes and influencing factors of VOCs in underground subway stations in the Seoul Metro before (2019) and after (2021) the COVID-19 pandemic. A total of 506 samples were collected from 253 stations on lines 1–8 between May 2019 and September 2021. Total VOC concentrations in Seoul Metro increased after the COVID-19 pandemic 3.8 times over. The deeper the underground station platform, the greater the difference in the VOC concentrations between 2019 and 2021, which was positively related. Average VOC concentration was the highest (52.8 µg/m3) at a depth of 25–30 m and the lowest (23.9 µg/m3) at a depth of < 10 m in 2019. In conclusion, excessive disinfection during the COVID-19 pandemic resulted in increased VOC concentrations in the Seoul Metro, especially in the deeper underground stations. Less frequent quarantine disinfection is recommended to improve air quality.

Molecular compositions and sources of organic aerosols at a rural site on the Guanzhong Plain, Northwest China: The importance of biomass burning

The concentration of PM2.5 has considerably reduced in recent years, but remains relatively high in China. In particular, the increasing contribution of organic compounds to PM2.5 generates popular pressure for further reductions, resulting in an urgent need to study organic aerosol (OA). To investigate the molecular composition and source contribution of OA in the rural area of the Guanzhong Plain, Northwest China, PM2.5 samples were collected during 3–23 August 2016 and 5–20 January 2017 and studied for more than 100 organic tracer compounds. The mean concentration of total measured organic compounds is 662 ± 296 ng/m3 in summer and 3258 ± 1925 ng/m3 in winter. Levoglucosan is the most abundant single compound found throughout the sampling period, which is a crucial tracer for biomass burning emissions, preliminary suggesting that biomass burning is an essential source of OA. In summer, organic compounds such as lipid compounds, sugar compounds, and polycyclic aromatic hydrocarbons (PAHs), more come from higher plants, wood burning, vehicle exhausts, plastic waste, and other direct emission sources. Oxygenated PAHs (OPAHs), nitrophenols, and phthalic acids more come from the atmosphere through the oxidation reaction of aromatic precursors, especially photochemical oxidation. However, in winter, most of the increases in concentrations of organic compounds are attributed to biomass burning. The analysis of a haze event (14–19 January 2017) during the winter sampling period shows that the increases in the concentration of organic compounds are unaccompanied by strong secondary formation under lower relative humidity (49.1% ± 13.5%). The main reason for the growth of OA in this haze event is the accumulation of primary OA (POA). The source apportionment by the positive matrix factorization (PMF) model shows that biomass burning (37.1%) is the primary source of OA in the rural regions of the Guanzhong Plain, especially in winter (40.6%). The contribution of secondary formation decreases from 26.0% in summer to 16.9% in winter, and the contribution of fossil fuel emissions is comparable across both seasons.

Assessing the impact of ventilation systems on indoor air quality: a mock-up experiment in Dubai

Indoor Air Quality (IAQ) has become an important concern in Dubai, driven by public health awareness, environmental regulations, and government initiatives. The Dubai Municipality has introduced guidelines and standards for IAQ in residential and non-residential buildings, emphasizing ventilation, material selection, and testing protocols. IAQ monitoring and testing are encouraged, and public awareness campaigns educate individuals about IAQ and its impact on health. Green building regulations in Dubai also address IAQ considerations. The Dubai Municipality has comprehensively assessed IAQ in public buildings, leading to stringent regulations. However, research on IAQ improvement and challenges associated with apartment ventilation systems is limited. This study aims to evaluate the IAQ improvement and potential issues of a ventilation system in an apartment through a mock-up experiment. Factors such as air volume, ventilation system type, and supply/exhaust duct configuration are analyzed. The results show that installing a ventilation device with a ventilation rate of 0.3–0.8 times/h reduces Formaldehyde (HCHO) and Volatile Organic Compounds (VOCs) concentrations by 30%–50%. The IAQ improvement is not significantly influenced by air volume. Each room supply/exhaust method shows a 10% higher reduction in VOC concentrations than the supply/kitchen exhaust unit method. Preventing backflow and addressing cold drafts are recommended during ventilation system installation. Noise measurements comply with standards in most cases. These findings contribute to developing guidelines for ventilation system design and installation in apartments, promoting healthier indoor environments. Further research with a broader range of ventilation devices and real-world conditions is recommended to validate these findings.

Research of gas exchange and air purification processes by plants of the common privet (Ligustrum vulgare L.) species

Growing urbanization creates air pollution problems, which is becoming dangerous for human health and unsuitable for indoor ventilation. An effective solution is the combination of green structures with engineering systems, which requires the development of new methods and quantitative laboratory studies of gas and mass exchange processes of plants. The purpose of the study was to quantify the ability of plants of the common privet (Ligustrum vulgare L.) to release and absorb oxygen and СО2, as well as to study the effectiveness of air purification from particulate matter in order to properly take into account the impact of plants in the process of their selection for greening urban landscapes. The research was carried out according to the methodology developed by the authors in a gas exchange chamber, which was upgraded to model external conditions and study plants with small leaf area and developed stems. The results of the experiment showed that Ligustrum vulgare L. bushes with a small total photosynthetic leaf surface area are inefficient for carbon dioxide absorption in an urbanized environment, so plants with a significant proportion of photosynthetically active biomass and fast-growing plants should be preferred. It was determined that at maximum illumination, the degree of absorption of PM2.5 and PM10 by Ligustrum vulgare L. bushes was 8.84‧10-5...1.5‧10-4 μg/s, which confirms the effective absorption of particulate matter with a diameter of up to 2.5 and up to 10 μm from the air by the studied plants. The results obtained indicate an increase in the concentration of total volatile organic compounds in the outlet compartment, which indicates the active release of volatile phyto-organic substances by plants in the amount of 2.442...2.973 μg/s. The results of the study can be used for effective taxonomic selection of woody plants during the design and creation of urban green spaces that are resistant to the conditions of the urban environment

An ultrasonic-assisted Synthesis, Characterization, and application of Nano-Fe3O4/TiO2 as nano-catalyst for the removal of organic dye by Like-Photo-Fenton reactions

In this research, Fe3O4 nanoparticles were synthesized via a simple co-precipitation method. Subsequently, these nanoparticles were used to synthesize TiO2-Fe3O4 nanocomposites via solvothermal ultrasonic-assisted method. Obtained nanomaterials Fe3O4 and TiO2-Fe3O4 were structurally characterized by UV–visible, XRD, and SEM-EDS. Synthesized nano-catalysts were tested as catalysis of organic dye degradation. Furthermore, an optimization study was conducted to evaluate selected TiO2-Fe3O4 nanocomposites to degrade Methylene Blue (MB) in an aqueous solution through Fenton-like reactions. Several experimental variables, including pH (from 2 to 8), H2O2 concentration (from 10-2 to 5.10-1M), catalyst amount (20 to 80 mg), and target organic compound concentrations, were tested in order to optimize the Fenton-like catalytic activity of the TiO2-Fe3O4 as a nano-catalyst to degrading MB under ambient light conditions (natural sunlight). The results showed that TiO2-Fe3O4 had an efficient degradation rate of up to 85% for MB at the optimal pH 3, H2O2 at 10-1M and 40 mg/L catalyst amount. Also, the results showed the good reusability of TiO2-Fe3O4 as a nanophotocatalyst. Also, based on the results of the scavenging agent experiments, hydroxyl radicals and superoxide radicals play an important role in methylene blue (MB) photodegradation. Finally, a possible mechanism for the photocatalytic degradation of MB was proposed. In this study, the synthesis and application of TiO2-Fe3O4 nanocomposite as a nano-catalyst in the Fenton-like oxidation process demonstrated a promising eco-friendly method for treating organic pollutants in water.