Chlorine Compounds Research Articles

Recent advances in microbially derived chlorinated antiparasitic compounds.

Parasitic diseases remain a significant global health challenge, especially in developing countries, contributing to approximately one million deaths annually. Notably, among the 143 FDA-approved antiparasitic drugs, thirty-four possess chlorine in their chemical structure, highlighting the importance of chlorine substitution. This underscores the significance of chlorine atoms in elucidating structure-activity relationships crucial for drug discovery, aiming to develop safer, more selective, and environmentally friendly molecules with enhanced efficacy. Of particular interest some are naturally occurring chlorinated metabolites derived from PKS, NRPS, and PKS-NRPS biosynthetic pathways, which offer the potential for further manipulation. However, there is limited literature on antiparasitic chlorinated compounds from microbial sources. To address this, we conducted a comprehensive literature survey from 1963 to the present, identifying 28 chlorinated compounds with confirmed antiparasitic properties. This review underscores the potential of enzymatic machinery for selective chlorine substitution, offering insights for biochemists and synthetic chemists to develop versatile chlorinated compounds through synthetic biology, combinatorial chemistry, and organic synthesis.

Analysis of environmental factors affecting the incidence of testicular cancer, with particular emphasis on testicular germ cell tumors (TGCTs). Literature review

Introduction: Testicular cancer is the most common malignancy among men in the 20-44 age group. Most of the incidence is testicular germ cell tumor. In recent years there has been a steady increase in the incidence of this cancer. For this reason, we analyzed available articles on environmental risk factors that may influence the incidence of increased testicular malignancies Material and methods: Review of the specialized literature in the field of urology and articles available on PubMed, searching by the keywords “testicular cancer,” “testicular cancer risk factors,” “germ cell tumor,” “tgct‘’Aim of the study: The purpose of the study is to review the available literature and research papers regarding risk factors for malignant tumors of the testis. Summary: In recent years, there has been an increase in the incidence of testicular cancer, especially among men aged 20-44 years. The vast majority of it is germ cell tumors (TGCT). This article discusses the influence of environmental factors on the development of testicular cancer, with particular emphasis on the induction of TGCT. Studies indicate an association between exposure to trichloroethylene and other solvents and the risk of TGCT induction. The role of exposure to pesticides (especially fungicides), organic chlorine compounds, and viruses was also indicated to increase the risk of developing TGCTs,. The association of neoplasia with marijuana and tobacco use has also been studied, but needs further research. There is a need for continued research regarding heavy metals, infertility and factors related to pregnancy and the perinatal period. It is necessary to know the mechanisms that induce the process of carcinogenesis in the testis, which will enable the use of prevention and prophylaxis.

In-situ activation of persulfate by emplaced magnetite nanoparticles for degradation of 1,2-dichloroethane in porous media

In this study, column experiments were conducted to explore on the method of emplacement of magnetite nanoparticles (MNPs) for in situ activation of persulfate (PS) in sand porous media to degrade 1,2-dichloroethane (DCA), a typical recalcitrant chlorinated compound. Different molar ratios between PS and DCA (0:1, 2:1, 5:1 and 20:1) and mass contents of MNPs in the sand (0%, 1.9% and 5.4%) were tested. In the absence of MNPs, degradation of DCA was negligible for a hydraulic retention time of 7 h. Presence of MNPs at the content of 1.9% enhanced degradation of DCA and the highest removal efficiency (34.2%) was observed at the PS-to-DCA molar ratio of 5:1. At the MNPs content of 5.4%, increase of the PS-to-DCA molar ratio from 2:1 to 20:1 lead to not only increase in DCA removal efficiency but also substantial enhancement in chloride production, indicating that high PS concentration could cause significant degradation of the Cl-containing intermediates. In contrast to MNPs, Fe3O4 solids with much larger size (∼1 μm) were much less effective in activating PS for DCA removal even at a significantly higher content in the medium. The transport data could be well fitted by the one-site chemical nonequilibrium model, which showed kinetic DCA sorption to the MNPs as a key process for the transport. In the long-term injection experiment, a stable and significant removal of DCA (∼50%) was observed for 254 days at the MNP content of 1.9 %. The results of this study show the potential of MNPs as a sustainable PS activator in injection-based in situ chemical oxidation for groundwater remediation.

Low-temperature dechlorination methods for pyrolysis oil of municipal plastic waste

Pyrolysis oil produced from municipal plastic waste can be utilized as fuel and various valuable chemicals as an alternative to petroleum. However, pyrolysis oil usually contains a relatively high concentration of chlorinated compounds, obstructing its utilization in the chemical industry. The present research reveals that pyrolysis oil contains inorganic chlorine and organochlorine compounds, and differentiated approaches should be considered to remove Cl from covalent and ionic chlorine linkages. Transition metal-based ZSM-5 catalysts showed remarkable dechlorination performance via mild C-Cl cracking of 1-chlorooctane and 4-chlorotoluene at 180 °C or below. The neutralization method of mixing pyrolysis oil with an alkaline solution quickly eliminated ionic chlorine from inorganic chlorine compounds, reducing Cl concentrations by up to 70 % at temperature below 40 °C. Based on the different dechlorinating pathways, an ideal combination of these two methods was suggested to enhance chlorine removal efficiency from pyrolysis oil.

The use of in vitro bioassays and chemical screening to assess the impact of a minimally processed vegetable facility on wastewater quality.

Fruit- and vegetable-processing facilities may contaminate wastewater via contaminants found in the produce and disinfecting chemicals used. These contaminants may include agrochemicals, pesticides, and disinfectants such as chlorine and quaternary ammonium compounds (QACs). Some compounds may exhibit harmful endocrine-disrupting activity. This study investigated the impact of a minimally processed vegetable facility on wastewater quality via in vitro bioassays and chemical screening. Estrogen activity was assessed via a yeast estrogen screen (YES), and (anti-)androgenic and glucocorticoid activities were evaluated via an MDA-kb2 reporter gene assay. The samples were screened via gas and liquid chromatography-tandem mass spectrometry (GC-MS/MS and LC-MS/MS) to identify target compounds, and GC coupled with time-of-flight mass spectrometry (GC-TOFMS) was used for non-targeted screening. Sample complexity and chemical profiles were assessed using GC-TOFMS. Estrogenic activity was detected in 16 samples (n = 24) with an upper limit of 595 ± 37ng/L estradiol equivalents (EEqs). The final wastewater before discharge had an EEq of 0.23ng/L, which is within the ecological effect-based trigger value range for the estrogenic activity of wastewater (0.2-0.4ng/L EEq). Androgenic activity was detected in one sample with a dihydrotestosterone equivalent (DHTEq) value of 10 ± 2.7ng/L. No antiandrogenic activity was detected. The GC-MS/MS and LC-MS/MS results indicated the presence of multiple pesticides, nonylphenols, triclocarban, and triclosan. Many of these compounds exhibit estrogenic activity, which may explain the positive YES assay findings. These findings showed that wastewater from the facility contained detergents, disinfectants, and pesticides and displayed hormonal activity. Food-processing facilities release large volumes of wastewater, which may affect the quality of the water eventually being discharged into the environment. We recommend expanding conventional water quality monitoring efforts to include additional factors like endocrine activity and disinfectant byproducts.

Effect of interaction between different plastics and polyvinyl chloride on the chlorine transformation behavior in volatiles during low-temperature pyrolysis

To reduce the pollution during the pyrolysis recovery of chlorine-containing plastic waste from different sources, effects of the interaction between different plastics and polyvinyl chloride (PVC) on the transformation of chlorine at low temperature were investigated by thermogravimetry-Fourier transform infrared (TG-FTIR) and fixed-bed pyrolysis experiments. Results showed that the proportions of chlorine in chars were all <0.04 %, indicating that almost all chlorine was released after pyrolysis. However, the chlorine forms in volatiles were significantly changed with mixing different plastics. HCl production was significantly inhibited due to the addition of other plastics, while the organic chlorinated compounds (OCCs) formation was promoted, which increased the distribution of chlorine in liquid products. During PVC pyrolysis, chlorine was mainly distributed in gas (93.09 %) in the form of HCl, only a small amount of aliphatic chlorides were generated and distributed in liquid (6.89 %). After the addition of polystyrene (PS), polyethylene (PE) and polyethylene terephthalate (PET), the chlorine distribution in liquid increased to 8.86 %, 11.98 % and 25.99 %, respectively. The formation of OCCs was significantly affected by the difference in thermochemical reaction characteristics of plastics. Specifically, the production of aromatic chlorides was promoted by PS, while the generation of aliphatic chlorides and aromatic chloroesters was significantly promoted by PE and PET, respectively. Therefore, the release form of chlorine could be significantly altered by the interaction between PVC and other waste plastics, which provides a reference for the regulation of chlorine-containing pollutants in the recovery and utilization of plastic waste.

A contemporary view of the mechanisms of formation of new contaminants in vegetable oils – esters of monochloropropanediols and high molecular weight carboxylic acids

Monochloropropanediols (MCPD) and their esters with high molecular weight carboxylic (fatty) acids are new types of technological contaminants present in refined deodorized oils and other foods.The development of measures to minimize the content of MCPD esters in vegetable oils, which are an important component of various food systems, is a priority direction of modern foreign and domestic research in the field of ensuring food safety. The effectiveness of such measures should be based on ideas about the mechanisms of formation of MCPD esters and the identification of their predecessors (precursors) present in the lipid complex of oil seeds, as well as those formed during their processing.Systematized statistically reliable scientific knowledge about the mechanisms of formation of MCPD esters and their derivatives is still missing. Presumably, the formation of MCPDs and their esters with fatty acids should correlate with the presence of chlorine compounds in oilseed raw materials and in the oil itself; chlorine-containing pesticides and biologically active substances (fertilizers) used in agricultural production are one of the sources.Thus, the goal of the research is a systematic and comprehensive synthesis of ideas about precursors and mechanisms of formation of MCPD esters.As a result of analysis and synthesis of literature sources, it has been established that the main precursors of MCPD esters are DAG, TAG and various chlorine-containing compounds. The main factors influencing the rate of formation and amount of accumulation of MCPD esters are high temperatures (more than 120°C), duration of heat treatment, the presence of free fatty acids, antioxidants and moisture. Different chlorine compounds appear to have different activities in the reactions leading to the formation of MCPD esters. The presence of antioxidants in lipid systems can inhibit the formation of 3-MCPD ester, and the effectiveness of the process is determined by the type of antioxidant. According to the degree of increase in inhibitory ability, the most applicable antioxidants in lipid systems can be ranked as follows: α-tocopherol, BOA, BOT, AP, PG and TBHQ. The role of the composition of fatty acids in the formation of MCPD esters still remains unclear; however, there is indirect evidence indicating the influence of the composition of fatty acids on the level of accumulation of MCPD esters, which determines the feasibility of an in-depth study of this issue.

Efficacy of Three Antimicrobials Against two SARS-COV-2 Surrogates, Bovine Coronavirus and Human Coronavirus OC43, on Hard or Soft Nonporous Materials

The efficacy of three antimicrobials was evaluated against two severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) surrogates – bovine coronavirus (BCoV) and human coronavirus (HCoV) OC43 – on hard and soft nonporous materials. Three antimicrobials with three different active ingredients (chlorine, hydrogen peroxide, and quaternary ammonium compound + alcohol) were studied. Initially, a neutralization method was optimized for each antimicrobial. Then, we determined their efficacy against BCoV and HCoV OC43 in both suspension and on surfaces made with polyethylene terephthalate (PET) plastic and vinyl upholstery fabric. All tests were conducted under ambient environmental conditions with a soil load of 5% fetal bovine serum. After a 2-min exposure, all three antimicrobials achieved a >3.0 log10 reduction in viral titers in suspension. All three also reduced virus infectivity on both surface materials below the detection limit (0.6 log10 TCID50/carrier). Treatments in which the reduction in virus titer was <3.0 log10 were attributed to a decreased dynamic range on the carrier during drying prior to disinfection. The carrier data revealed that both surrogates were inactivated more rapidly (p <0.05) on vinyl or under conditions of high relative humidity. Three classes of antimicrobials were efficacious against both SARS-CoV-2 surrogate viruses, with BCoV demonstrating slightly less sensitivity compared to HCoV OC43. These findings also illustrate the importance of (1) optimizing the neutralization method and (2) considering relative humidity as a key factor for efficacy testing.

Insights into the effect of operating parameters and hydrodynamics on hydrolysis reaction in Copper–Chlorine thermochemical water splitting cycle for hydrogen production: Modelling and experimental validation

Copper–Chlorine (Cu–Cl) thermochemical cycle is being explored as one of the promising technologies for large scale production of clean hydrogen from water using nuclear or renewable energy. In this method, water splitting is achieved through a series of reactions in a loop producing only hydrogen and oxygen with complete recycle of all the intermediate copper and chlorine compounds. The first step of the cycle is the hydrolysis reaction wherein steam reacts with solid CuCl2 to form solid Cu2OCl2 (copper oxychloride) and HCl gas. The products enter the subsequent steps of the cycle and are recycled back to complete the loop. Multiple side reactions in the hydrolysis step result in reduced yield and loss of chemicals from the cycle. Efficient reactor design and optimal operating conditions of hydrolysis reactor is imperative towards achieving sustained closed loop operation and reducing the energy demand of Cu–Cl cycle. This paper presents a mathematical model for the simulation of hydrolysis reaction in a bubbling fluidized bed reactor. The one-dimensional model is developed based on modified two-phase theory of fluidization and is coupled with kinetics of multiple side reactions to investigate the effect of operating parameters and hydrodynamics on the conversion and yield of Cu2OCl2. The model results are validated with experimental data in 50 mm and 100 mm semi-batch fluidized bed reactors. The developed model clearly brings out the effect of different process parameters for process optimization and scale-up of the hydrolysis reactor for efficient integration in the cycle.

Combination of photodynamic therapy with antibiotic therapy - future or misalliance?

SignificanceThe growing antibiotic resistance of microorganisms is an increasingly important challenge for modern medicine. In the next few decades, the so-called post antibiotic era is likely to begin. For this reason, the search for new solutions using PACT seems particularly promising. ApproachFour new chlorin compounds were tested and photochemically characterized for singlet oxygen generation efficiency and photostability. They have been evaluated for bactericidal properties against MRSA, E. coli (ESBL+) and C. albicans. Their synergism with antibiotics from the group of cephalosporins and carbapenems was evaluated. ResultsA reduction of approximately 3 logs or more was achieved for each of the bacterial strains. A decrease in MIC values was observed for all bacteria, the greatest for ceftriaxone. ConclusionsCombining traditional antibiotic therapy with PACT may be a promising route in the case of antibiotic-resistant infections, but requires further in-depth research.

Arming Amorphous NiMoO4 on Nickel Phosphide Enables Highly Stable Alkaline Seawater Oxidation.

Seawater electrolysis holds tremendous promise for the generation of green hydrogen (H2). However, the system of seawater-to-H2 faces significant hurdles, primarily due to the corrosive effects of chlorine compounds, which can cause severe anodic deterioration. Here, a nickel phosphide nanosheet array with amorphous NiMoO4 layer on Ni foam (Ni2P@NiMoO4/NF) is reported as a highly efficient and stable electrocatalyst for oxygen evolution reaction (OER) in alkaline seawater. Such Ni2P@NiMoO4/NF requires overpotentials of just 343 and 370mV to achieve industrial-level current densities of 500 and 1000mA cm-2, respectively, surpassing that of Ni2P/NF (470 and 555mV). Furthermore, it maintains consistent electrolysis for over 500h, a significant improvement compared to that of Ni2P/NF (120h) and Ni(OH)2/NF (65h). Electrochemical in situ Raman spectroscopy, stability testing, and chloride extraction analysis reveal that is situ formed MoO4 2-/PO4 3- from Ni2P@NiMoO4 during the OER test to the electrode surface, thus effectively repelling Cl- and hindering the formation of harmful ClO-.

Experimental Research into an Innovative Green Propellant Based on Paraffin–Stearic Acid and Coal for Hybrid Rocket Engines

This study focuses on an innovative green propellant based on paraffin, stearic acid, and coal, used in hybrid rocket engines. Additionally, lab-scale firing tests were conducted using a hybrid rocket motor with gaseous oxygen as the oxidizer, utilizing paraffin-based fuels containing stearic acid and coal. The mechanical performance results revealed that the addition of stearic acid and coal improved the mechanical properties of paraffin-based fuel, including tensile, compression, and flexural strength, under both ambient and sub-zero temperatures (−21 °C). Macrostructural and microstructural examinations, conducted through optical and scanning electron microscopy (SEM), highlighted its resilience, despite minimal imperfections such as impurities and micro-voids. These characteristics could be attributed to factors such as raw material composition and the manufacturing process. Following the mechanical tests, the second stage involved conducting a firing test on a hybrid rocket motor using the new propellant and gaseous oxygen. A numerical simulation was carried out using ProPEP software to identify the optimal oxidant-to-fuel ratio for the maximum specific impulse. Following simulations, it was observed that the specific impulse for the paraffin and for the new propellant differs very little at each oxidant-to-fuel (O/F) ratio. It is noticeable that the maximum specific impulse is achieved for both propellants around the O/F value of 2.2. It was observed that no hazardous substances were present, unlike in traditional solid propellants based on ammonium perchlorate or aluminum. Consequently, there are no traces of chlorine, ammonia, or aluminum-based compounds after combustion. The resulting components for the simulated motor include H2, H2O, O2, CO2, CO, and other combinations in insignificant percentages. It is worth noting that the CO concentration decreases with an increase in the O/F ratio for both propellants, and the differences between concentrations are negligible. Additionally, the CO2 concentration peaks at an O/F ratio of around 4.7. The test proceeded under normal conditions, without compromising the integrity of the test stand and the motor. These findings position the developed propellant as a promising candidate for applications in low-temperature hybrid rocket technology and pave the way for future advancements.

Evaluating groundwater ecosystem dynamics in response to post in-situ remediation of mixed chlorinated volatile organic compounds (CVOCs): An insight into microbial community resilience, adaptability, and metabolic functionality for sustainable remediation and ecosystem restoration

The in-situ remediation of groundwater contaminated with mixed chlorinated volatile organic compounds (CVOCs) has become a significant global research interest. However, limited attention has been given in understanding the effects of these remediation efforts on the groundwater microbial communities, which are vital for maintaining ecosystem health through their involvement in biogeochemical cycles. Hence, this study aimed to provide valuable insights into the impacts of in-situ remediation methods on groundwater microbial communities and ecosystem functionality, employing high-throughput sequencing coupled with functional and physiological assays. The results showed that both bioremediation and chemical remediation methods adversely affected microbial diversity and abundance compared to non-polluted sites. Certain taxa such as Pseudomonas, Acinetobacter, and Vogesella were sensitive to these remediation methods, while Aquabacterium exhibited greater adaptability. Functional annotation unveiled the beneficial impact of bioremediation on the sulfur cycle and specific taxa such as Cellvibrio, Massilia, Algoriphagus, and Flavobacterium which showed a significant positive relationship with dark oxidation of sulfur compounds. In contrast, chemical remediation showed adverse impacts on the nitrogen cycle with a reduced abundance of nitrogen and nitrate respiration along with a reduced utilization of amines (nitrogen rich substrate). The findings of this study offer valuable insights into the potential impacts of in-situ remediation methods on groundwater microbial communities and ecosystem functionality, emphasizing the need for meticulous consideration to ensure the implementation of effective and sustainable remediation strategies that safeguard ecosystem health and function.

Augmented degradation performance of dielectric barrier discharge plasma via optimized hydroxyl radical generation

Dielectric barrier discharge (DBD) plasma demonstrates significant potential for eliminating chlorinated aromatic compounds (CACs), while its commercial application has been hampered by inadequate generation and diffusion of active species. In response, this work introduced iron-biochar composites (Fe/BC) into DBD system to enhance the generation of highly oxidative hydroxyl radicals (OH) from underutilized O3 and H2O2, thereby reducing the diffusion of OH and accelerating the degradation of CACs. The results indicated that, in just 15 min, the combined system achieved remarkable degradation rates exceeding 95% for six diverse CACs, with the degradation rate constant increasing up to 4.27 times when compared to DBD alone. Moreover, the varied response of pollutants implied that the enhanced degradation efficiency was primarily facilitated by the reduced mass transfer distance between pollutants and formed OH. The activation of O3 on Lewis acidic sites not only directly promoted the generation of OH through free radical chain reactions but also indirectly induced more conversion of H2O2 into OH by facilitating the Fe3+/Fe2+ cycle. The identification of intermediates and toxicity analysis substantiated its environmental sustainability. This study offers a viable technical pathway and theoretical foundation for enhancing the efficiency of plasma-based treatment of organic wastewater.

Evaluation of approaches to increase the effectiveness of various disinfectants against biofilm communities of different ages

Disinfectants are used as the main agents against microorganisms circulating on the surfaces of food enterprises. However, the adaptive ability of microorganisms to form biofilms complicates the process of surface cleaning and reduces the effectiveness of disinfectants. Modern disinfectants act against freely circulating microflora, but it is known that they are not always effective against biofilms. The purpose of this study was to investigate effective disinfectant compositions with bactericidal effect on binary bacterial biofilms of different ages. The article describes the effects of disinfectants based on chlorine, peracetic acid and quaternary ammonium compounds with enzymes in concentrations recommended by the manufacturer and increased several times on Salmonella 38, Brochothrix thermosphacta 2726 and Staphylococcus equorum 2736 planktonic cultures and binary biofilms. Binary biofilms of different ages (2 and 9 days old) were exposed to disinfectants with various active ingredients in combination with adjuvants, i. e. hydrogen peroxide 6% and various concentrations of isopropyl alcohol (30%). All products in concentrations recommended by the manufacturer did not have a disinfectant effect against the studied biofilm cultures. As a result of the work, it was found that the most effective disinfectants against multispecies biofilms were quaternary ammonium compounds in combination with enzymes and chlorine in combination with isopropyl alcohol (30%). The results obtained allow to expand knowledge about effective methods for controlling biofilms.

A comprehensive literature scoping review of infection prevention and control methods for viral-mediated gene therapies.

This comprehensive literature scoping review outlines available infection prevention and control (IPC) methods for viral-mediated gene therapies and provides one IPC strategy for the healthcare setting based on a single-center recommendation. A team of experts in pharmacy, healthcare epidemiology, and biosafety with experience in viral-mediated gene therapy was assembled within a pediatric hospital to conduct a comprehensive literature scoping review. The comprehensive review included abstracts and full-text articles published since 2009 and utilized prespecified search terms of the five viral vectors of interest: adenovirus (AV), retrovirus (RV), adeno-associated virus (AAV), lentivirus (LV), and herpes simplex virus (HSV). Case reports, randomized controlled trials, and bench research studies were all included, while systematic reviews were excluded. A total of 4473 case reports, randomized control trials, and benchtop research studies were identified using the defined search criteria. Chlorine compounds were found to inactivate AAV and AV, while alcohol-based disinfectants were ineffective. There was a relative paucity of studies investigating surface-based disinfection for HSV, however, alcohol-based disinfectants were effective in one study. Ultraviolent irradiation was also found to inactivate HSV in numerous studies. No studies investigated disinfection for LV and RV vectors. The need to define IPC methods is high due to the rapid emergence of viral-mediated gene therapies to treat rare diseases, but published clinical guidance remains scarce. In the absence of these data, our center recommends a 1:10 sodium hypochlorite solution in clinical and academic environments to ensure complete germicidal activity of viral-mediated gene therapies.

A stamped aluminium gas chromatographic column disk employing directly grown anodic aluminium oxide stationary phase for the separation of aromatic and chlorinated compounds.

In this study, mesoporous anodic aluminium oxide (AAO) with moderate polarity was used as a GC stationary phase to demonstrate the applicability to various compound species. The fluidic channel measured 6 meters in length and had a cross-section area of 0.127 mm2. The column disk measured 6.2 cm in diameter and was fabricated through a stamping process on an aluminium substrate. The AAO stationary phase was directly grown on the aluminium substrate through an anodization process using oxalic acid as the electrolyte. The pore size of the AAO stationary phase was approximately 50-70 nm, with film thicknesses ranging from 6-20 μm. AAO based on oxalic acid exhibited significantly reduced surface polarity, making it suitable for separating polarizable and slightly polar compounds. The theoretical plate number for benzene had reached 1800 plates per meter, and for n-butane, it had reached 2500 plates per meter. A complex mixture of 16 compounds spanning alkanes, olefins, aromatics, and chlorinated hydrocarbons was effectively separated in 8 minutes with the temperature programmed to 200 °C.

ESTUDO TEÓRICO E EXPERIMENTAL DE DERIVADOS DE CLORINAS E BACTERIOCLORINAS VISANDO A SUSTENTABILIDADE

THEORETICAL AND EXPERIMENTAL STUDY OF CHLORINS AND BACTERIOCHLORINS DERIVATIVES AIMING FOR SUSTAINABILITY. Porphyrinoid compounds such as chlorins and bacteriochlorin have currently been widely studied to remedy health problems, develop new technologies, apply in solar cells, and decontaminate food, aiming for sustainability. Its wide applicability demonstrates the potential of these derivatives to solve society’s problems. Thus, this work seeks to understand more about the reactivity and properties of these derivatives. In this way, structural changes were made to chlorophyll, giving rise to three chlorin compounds (1-3), and also to bacteriochlorophyll, giving rise to three bacteriochlorins (4-6). The experimentally obtained results were analyzed by infrared and UV-Vis spectroscopy and the experimental spectroscopic data were compared with data obtained theoretically with Gaussian 09 software, using density functional theory (DFT), such as B3LYP and CAM-B3LYP. After the analyses, it was observed that the data obtained experimentally are quite similar to those obtained theoretically. Thus, it is possible to demonstrate that theoretical calculations are useful tools and can help predict molecules, often avoiding the synthesis of a given molecules in the laboratory, minimizing the use of reagents and solvents and thus contributing to sustainability.

Synthesis and evaluation of the anti-bacterial effect of modified silica gel supported silver nanoparticles on E. coli and S. aureus

Scientists are looking for new antibacterial agents to disinfect point-of-use water sources due to the dearth of clean drinking water in developing nations and disaster areas. Because of the growth of antibiotic and disinfectant resistance as well as the emergence of multiple unfavorable effects brought on by using current antibacterial agents like chlorine compounds, this is the case. Because of their antibacterial properties, silver nanoparticles (AgNPs) have become a useful replacement for other nanomaterials. This study aimed to evaluate the antibacterial activity of AgNPs embedded in modified silica gel (MSG). It was used to kill Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) and to test its efficacy in water purification in a batch and zone of inhibition system. Trimethyl chlorosilane (TMCS) was used to modify MSG, which was then ground into powder using a process known as the ambient dry method. Using a reagent made from Vernonia amygdalina leaf extract, AgNPs were prepared using a green technique. With the aid of FT-IR, BET, XRD, SEM/EDX, and UV–vis spectrophotometers, the MSG supported by AgNPs was studied. E. coli and S. aureus were tested for their antibacterial abilities in MSG supplements with AgNPs samples. AgNPs have excellent antibacterial properties that enable zone inhibition and batch system tests with MSG. Batch system tests showed that both gram-positive and gram-negative microorganisms decreased effectively after 10 min of exposure. Zone inhibition tests indicated that MSG with AgNPs was effective against both kinds of bacteria.

Influence of organic matters on the adsorption-desorption of 1,2-dichloroethane on soil in water and model saturated aquifer.

1,2-Dichloroethane (1,2-DCA) is a typical organic chlorinated compound largely utilized in chemical manufacturing and industrial production and also a common pollutant in organically contaminated sites. The adsorption of 1,2-DCA on soil grains significantly influences its environmental fate and removal process. This study investigated the influence of fulvic acid (FA) and humic acid (HA) on the adsorption-desorption of 1,2-DCA in solid-liquid interfaces in water or constructed porous media. Experimental findings demonstrated the influence of organic matter on the adsorption of 1,2-DCA at the solid-water interface. 1,2-DCA adsorption increased in the FA or HA-treated soils when organic matter was present on the solid surfaces. The 1,2-DCA adsorption in the mixture of FA and HA was slightly lower than that in single organic acids, depending on the binding of FA and HA to the soil grains/colloids. Basic conditions reduced the adsorption of 1,2-DCA on soils, whereas acidic conditions enhanced adsorption due to the increased interactions via adsorption sites and hydrogen bonds. Conversely, the presence of organic matter in solutions (liquid phase in constructed porous media) will reduce the adsorption of 1,2-DCA on solid surfaces and increase the transport in the model aquifer. The combination of FA, HA, and rhamnolipids is helpful for the removal of 1,2-DCA from solid surfaces. Additionally, because of the enhanced desorption, the risk of 1,2-DCA contamination in groundwater can be increased when the organic matter or surfactant is present in the liquid phase if the eluent is not collected. This study helps to better understand the cooperative interaction of soil organic matter and chlorinated hydrocarbons at solid-water interfaces and the environmental fate and potential removal strategies of chlorinated hydrocarbons in contaminated sites.