Physicochemical Characteristics Research Articles

The Occurrence, Distribution, Environmental Effects, and Interactions of Microplastics and Antibiotics in the Aquatic Environment of China

Microplastics (MPs) and antibiotics (ATs) have been detected in various aquatic environments and characterized as novel contaminants that have attracted worldwide attention. This review summarizes the characteristics of MPs and ATs, analyzes the sources of MPs and ATs in aquatic environments, reviews the concentration distribution of the two pollutants in China, and introduces the environmental effects of mixing MPs and ATs. Studies on single pollutants of MPs or ATs are well established, but the interactions between the two in aquatic environments are rarely mentioned. The physicochemical characteristics of MPs make them carriers of ATs, which greatly increase their risk of being potential hazards to the environment. Therefore, in this article, the interaction mechanisms between MPs and ATs are systematically sorted out, mainly including hydrophobic, electrostatic, intermolecular interactions, microporous filling, charge-assisted hydrogen bonding, cation-bonding, halogen bonding, and CH/π interactions. Also, factors affecting the interaction between ATs and MPs, such as the physicochemical properties of MPs and ATs and environmental factors, are also considered. Finally, this review identifies some new research topics and challenges for MPs and ATs, in order to gain deeper insight into their behavioral fate and toxic mechanisms.

Synthesis and utilization of titanium dioxide nano particle (TiO2NPs) for photocatalytic degradation of organics

A green technique that emerged as a promise in the degradation of numerous organic contaminants is photocatalysis. The aim of this study concerns photocatalytic degradation of organic using titanium dioxide nano particles (TiO2 NPs) which syntheses from ilmenite by different leaching methods using different ingredients such as HCl, HNO3 and Aqua Regia. The affecting factors such as rate of addition, reaction time, ilmenite grain size, acid to ilmenite ratio and reaction temperature were conducted. Comprehensive physicochemical characterization of Ilmenite and TiO2 NPs were conducted using different analytical techniques such as XRD, XRF, SEM, TEM and FTIR. Photocatalytic degradation of organics is confirmed by studies of affecting factors on the effectiveness of TiO2 NPs such as dose, agitation forces, light intensity, initial concentration, pH, time, and temperature. The removal percentages of TSS, COD, BOD and TN of organics were explored. From the results the maximum removal percentage of TSS were 97.3 and 96.9% before and after secondary treatment conducted using ferric chloride (FC). The maximum removal percentage of TKN, BOD, and COD before secondary treatment were conducted using mixture of TiO2 NPs, FC, and chitosan, which reached 44.2, 44 and 46.3%, respectively. The maximum removal percentage of TKN, BOD, and COD after secondary treatment were conducted using mixture of TiO2 NPs, FC, and chitosan, which reached 94.9, 99.7 and 99.6%, respectively. Overall, the results derived from this investigation suggest that the TiO2 NPs/UV holds significant advanced treatment of sewage water, making it a viable choice for water reuse applications.

Mesoporous Pdx-Nix aerogels for electrocatalytic evaluation of urea-assisted electrolysis

AbstractThis work presents the synthesis and evaluation of Pd-Ni aerogels toward the urea oxidation reaction (UOR). The incorporation of Ni led to a 0.13 V reduction in the energy required for the oxidation and reduction of PdO compared to monometallic Pd, both in alkaline medium with and without urea. Varying the Ni ratios in Pd (Pd-Ni 4:1, Pd-Ni 1:1, and Pd-Ni 1:4) led to significant changes in the electrochemical behaviour. In alkaline medium without urea, PdNi 4:1 showed the formation of NiOOH at 1.35 V, which promoted oxygen diffusion on the electrode surface and increased the current density, confirming the increase in the active sites of NiOOH and NiPdOOH and enabling urea-based electrolysis at these sites. While palladium aerogels alone are ineffective for UOR, the presence of nickel plays a key role in enhancing the UOR efficiency. On the other hand, physicochemical characterisation revealed that PdNi 4:1 has a crystal size of 4.37 nm and a larger shift in the 2θ positions of the (111) and (200) planes, which favours electronic changes that were investigated by XPS. These changes affected the electrocatalytic activity, which is primarily related to electronic effects. The results of SEM and TEM studies and nitrogen adsorption-desorption isotherm confirmed that the aerogels are highly porous and have an effective surface area and abundant active sites for reactions that allow efficient mass transfer and low diffusion resistance. TEM observations revealed interconnected nanochains indicating optimal electrocatalytic activity for both ORR and UOR due to high mass transfer. These interconnected networks are crucial for improving electrocatalytic activity in the urea oxidation reaction.

Peroxymonosulfate activation by superparamagnetic mixed-valent Cu/N-(L-cysteine)-O-(carboxymethyl)chitosan/cobalt ferrate-rice hull hybrid nanocomposite for efficient degradation of naproxen: Synergetic adsorption-catalysis, kinetics, pathway, and relevant mechanism.

Naproxen (NPX) as an emerging anthropogenic contaminant was detected in many water sources, which can pose a serious threat to the environment and human health. Peroxymonosulfate (PMS) decomposed by Cu(I) has been considered an effective activation method to produce reactive species. However, this decontamination process is restricted by the slow transformation of Cu(II)/Cu(I) by PMS. Herein, new N-(L-cysteine/triazine)-O-(carboxymethyl)-chitosan/cobalt ferrate-rice hull hybrid biocomposite was constructed to anchor the mixed-valent Cu(I)-Cu (II) (CuI, II-CCCF) for removing pharmaceutical pollutants (i.e., naproxen, ciprofloxacin, tetracycline, levofloxacin, and paracetamol). The structural, morphological, and catalytic properties of the CuI,II-CCCF have been fully identified by a series of physicochemical characterizations. Results demonstrated that the multifunctional, hydrophilic character, and negative ζ-potential of the activator, accelerating the redox cycle of Cu(II)/Cu(I) with hydroxyl amine (HA). The negligible metal leaching, well-balanced thermodynamic-kinetic properties, and efficient adsorption-catalysis synergy are the main reasons for the significantly enhanced catalytic performance of CuI,II-CCCF in the removal of NPX (98.6 % at 7.0 min). The main active species in the catalytic degradation of NPX were identified (●OH > SO4●- > 1O2 > > O2●-) and consequently suggested a degradation path. It can be noted that these types of carbohydrate-based nanocomposite offer numerous advantages, encompassing simple preparation, excellent decontamination capabilities, and long-term stability.

Efficiency and Mechanistic Insights of Photocatalytic Decomposition of Tetracycline and Rhodamine B utilizing Z-scheme g-C3N4/SnWO4 Heterostructures under Visible Light Irradiation

The hydrothermal approach was used in the design and construction of the SnWO4 (SW) nanoplates anchored g-C3N4 (gCN) nanosheet heterostructures. Morphology, optical characteristics, and phase identification were investigated. The heterostructure architect construction and successful interface interaction were validated by the physicochemical characteristics. The test materials were used as a photocatalyst in the presence of visible light to break down the antibiotic tetracycline (TC) and the organic Rhodamine B (RhB). The best photocatalytic degradation efficiency of TC (97%) and RhB (98%) pollutants was demonstrated by the optimized 15 mg of gCNSW-7.5 in 72 and 48 minutes, respectively, at higher rate constants of 0.0409 and 0.0772 min–1. The interface contact between gCN and SW, which successfully enhanced charge transfer and restricted recombination rate in the photocatalyst, is responsible for the enhanced performance of the gCNSW heterostructure photocatalyst. In addition, the gCNSW heterostructure photocatalyst demonstrated exceptional stability and reusability over the course of four successive testing cycles, highlighting its durable and dependable function. Superoxide radicals and holes were shown to be key players in the degradation of contaminants through scavenger studies. The charge transfer mechanism in the heterostructure is identified as Z-scheme mode with the help of UV-vis DRS analysis. Attributed to its unique structural features, and effective separation of charge carriers, the Z-scheme gCNSW-7.5 heterostructure photocatalyst exhibits significant promise as an exceptionally efficient catalyst for the degradation of pollutants. This positions it as a prospective material with considerable potential across various environmental applications.

Monitoring and Assessment of the Quality of Chlorinated Water in Schools

All water destined for human consumption must be subjected to disinfection processes via chlorination with the aim of eliminating the risk of the transmission of waterborne diseases. However, the treatment of water using this method leads to the formation of trihalomethanes (THMs), which are toxic compounds that may be ingested, inhaled, or absorbed by the skin, increasing the risk of carcinogenic and mutagenic processes. High trihalomethane concentrations in water may be directly related to physicochemical properties, such as temperature, pH, hardness, and potentially toxic metal concentrations. In this work, physicochemical characterization was performed and water quality was assessed with regard to the presence of trihalomethanes in 17 samples collected from points before and after storage in reservoirs. Atomic absorption spectroscopy to determine potentially toxic metals and the measurement of physicochemical properties demonstrated that all results were in accordance with the standards established by Brazilian legislation. Gas chromatography–mass spectrometry was used to determine levels of trihalomethanes in the water samples (trichloromethane, bromodichloromethane, chlorodibromomethane, and bromoform), which were also in accordance with the limits established by Brazilian legislation. Hierarchical clustering on principal components confirmed changes in the water quality depending on location. This work constitutes a paradigm for future studies on the monitoring of toxic organic compounds in water to avoid health problems in humans and animals.

WLB-87848, a Selective σ1 Receptor Agonist, with an Unusually Positioned NH Group as Positive Ionizable Moiety and Showing Neuroprotective Activity.

The synthesis and pharmacological activity of a new series of thieno[2,3-d]pyrimidin-4(3H)-one derivatives as sigma-1 receptor (σ1R) ligands are reported. A hit from a high-throughput screening program was evolved into a highly potent and selective σ1R agonist (14qR) that contains a free NH group as positive ionizable moiety, not fulfilling the usual pharmacophoric features of the σ1R. The compound shows good physicochemical and ADMET characteristics, displays an agonist profile in the binding immunoglobulin protein/σ1R association assay, induces neuron viability in an in vitro model of β-amyloid peptide intoxication, and presents positive results against recognition memory impairment induced by hippocampal injection of Aβ peptide in rats after oral treatment, altogether making 14qR (WLB-87848) an interesting candidate for neuroprotection.

The Affects of Ce Doping Cr\(_2\)O\(_3\) Based Catalysts Supported on Activated Carbon for 1,2-Dichloroethane Abatement

Hydrothermal method is used to prepare activated carbon (AC) supported chromium-based catalysts for the catalytic combustion of 1,2-dichloroethane (DCE). The physicochemical properties relating catalysts are evaluated by several characterization techniques such as XRD, SEM, XPS, N2 adsorption-desorption isotherms, H2-TPR and NH3-TPR. The outcomes demonstrated that the Cr2O3 is the perfect targeted base catalyst adding to the facts that the hydrothermal approach is an appropriate way to create catalysts with superior properties. The textural characteristics, reducibility, and acidity of the Cr-based catalysts were all enhanced by the addition of cerium (Ce) and AC. Nevertheless, the research shows how crucial the Ce doping amount is for adjusting the physicochemical characteristics and catalytic efficacy of Cr-based catalysts. The catalyst 20Ce-Cr/AC has the maximum catalytic activity when it came to DCE combustion, where its T50 and T90 attaining of 247°C and 269.5°C, correspondingly. This is explained by the ideal Ce doping level, which improves the redox characteristics and revealed more active sites.

Physicochemical characterization of rice straw before and after alkali-assist photocatalytic pretreatment: a comparative analysis.

The potential of alkali-assist photocatalytic (AAP) pretreatment to overcome the recalcitrant nature of lignocellulose biomass, i.e. rice straw (RS), was investigated in the present study. Box-Behenken Design (BBD) using standard response surface methodology (RSM) approach was considered to obtain optimal conditions for maximum delignification. The model was designed with three variables: alkali concentration (NaOH, 0-3% w/v), photocatalyst (TiO2 NPs (titania nanoparticles), 0-1g/L) and pretreatment time (30-240min). The availability of cellulose was increased by 96.73%, while the concentration of lignin and hemicellulose decreased by 73.89%, and 71.79%, respectively, at a combination of 1.5% NaOH, 0.5g/L TiO2 NPsand 135 min pretreatment time. The structural and morphological alterations in the RS were assessed via Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) both before and after AAPpretreatment. The FTIR measurement indicated that the original RS included a significant quantity of lignin, which was eliminated after the pretreatment procedure. The XRD pattern demonstrates that cellulose crystallinity is significantly affected by the pretreatment. The SEM analysis revealed structural distortion and surface porosity from the pretreatment procedure.

Nano-Sheets of CsNiVF6 Pyrochlore Electrocatalyst for Enhanced Urea Oxidation and Hydrogen Green Production Reactions

This study presents the successful synthesis of a cesium–nickel–vanadium fluoride (CsNiVF6) pyrochlore nano-sheet catalyst via solid-phase synthesis and its electrochemical performance in green hydrogen production through urea electrolysis in alkaline media. The physicochemical characterizations revealed that the CsNiVF6 exhibits a pyrochlore-type structure consisting of a disordered cubic corner-shared (Ni, V)F6 octahedra structure and nano-sheet morphology with a thickness ranging from 10 to 20 nm. Using the CsNiVF6 catalyst, the electrochemical analysis, conducted through cyclic voltammetry, demonstrates a current mass activity of ~1500 mA mg−1, recorded at 1.8 V vs. RHE, along with low-resistance (3.25 ohm) charge transfer and good long-term stability for 0.33 M urea oxidation in an alkaline solution. Moreover, the volumetric hydrogen production rate at the cathode (bare nickel foam) is increased from 12.25 to 39.15 µmol/min upon the addition of 0.33 M urea to a 1.0 KOH solution and at a bias potential of 2.0 V. The addition of urea to the electrolyte solution enhances hydrogen production at the cathode, especially at lower voltages, surpassing the volumes produced in pure 1.0 M KOH solution. This utilization of a CsNiVF6 pyrochlore nano-sheet catalyst and renewable urea as a feedstock contributes to the development of a green and sustainable hydrogen economy. Overall, this research underscores the potential use of CsNiVF6 as a cost-effective nickel-based pyrochlore electrocatalyst for advancing renewable and sustainable urea electrolysis processes toward green hydrogen production.

A template wizard for the cocreation of machine-readable data-reporting to harmonize the evaluation of (nano)materials.

Making research data findable, accessible, interoperable and reusable (FAIR) is typically hampered by a lack of skills in technical aspects of data management by data generators and a lack of resources. We developed a Template Wizard for researchers to easily create templates suitable for consistently capturing data and metadata from their experiments. The templates are easy to use and enable the compilation of machine-readable metadata to accompany data generation and align them to existing community standards and databases, such as eNanoMapper, streamlining the adoption of the FAIR principles. These templates are citable objects and are available as online tools. The Template Wizard is designed to be user friendly and facilitates using and reusing existing templates for new projects or project extensions. The wizard is accompanied by an online template validator, which allows self-evaluation of the template (to ensure mapping to the data schema and machine readability of the captured data) and transformation by an open-source parser into machine-readable formats, compliant with the FAIR principles. The templates are based on extensive collective experience in nanosafety data collection and include over 60 harmonized data entry templates for physicochemical characterization and hazard assessment (cell viability, genotoxicity, environmental organism dose-response tests, omics), as well as exposure and release studies. The templates are generalizable across fields and have already been extended and adapted for microplastics and advanced materials research. The harmonized templates improve the reliability of interlaboratory comparisons, data reuse and meta-analyses and can facilitate the safety evaluation and regulation process for (nano) materials.

Standardization on Fermentation of Chia (Salvia hispanica L.)

Aims: To investigate the fermentation parameters physico-chemical characteristics and to conduct sensory evaluation to assess the acceptability of the fermented chia seeds. Study Design: Experimental study involving the fermentation of chia seeds with varying combinations of water, curd, and honey. Assessment of fermentation parameters and physico-chemical characteristics. Microbiological analysis, LAB isolation, and measurement of TSS, acidity, and pH. Sensory evaluation to determine the acceptability of the fermented chia seeds. Place and Duration of Study: The study undertaken during 2020-23 in the Department of Food Science and Nutrition, University of Agricultural Sciences, GKVK, Bangalore, Karnataka. Methodology: Chia seeds subjected to different fermentation treatments involving combinations of water, curd, and honey. Microbiological analysis conducted to assess microbial populations. Isolation of lactic acid bacteria (LAB) to study their presence. Measurement of total soluble solids (TSS), acidity, and pH to evaluate physico-chemical changes during fermentation. Sensory evaluation performed to determine consumer acceptability. Results: Fermentation treatments showed significant differences in soluble solids ranged (1.63 to 8.10), pH (1.87 to 3.87), and acidity, showcasing organic acid content, notably lactic acid (0.04 to 0.23), oxalic acids (0.04 to 0.23), citric acid (0.09 to 0.50), maleic acid (0.06 to 0.35) and succinic acid (0.05 to 0.30. Fermented white chia with distilled water + curd+ honey (FWC3) and Fermented black chia with distilled water + curd+ honey (FBC3) had the statistically higher mean sensory scores.

Development and Validation of 1H Nuclear Magnetic Resonance Quantitative Method for Efavirenz API Quality Control

Background: The pharmaceutical industry is constantly looking for a better way to ensure and improve its products' safety, quality, and effectiveness. Since there are many attributes of the drug substance and excipients that could potentially affect the Critical Quality Attributes (CQAs) of the intermediates and the final product, the evaluation of the raw material's physicochemical characteristics is crucial as they directly affect the quality, safety, efficacy, and lot-to-lot consistency. Scientists rely on methods, like HPLC, HPTLC, LC-MS, GC-MS, and NMR, to analyze these substances. The advantage of NMR is that it is considered a primary analytical method compared to other analytical techniques. Objective: This work aimed to present a simple, rapid, specific, and accurate method by proton Nuclear Magnetic Resonance spectroscopy (1H-NMR) developed to determine the activity of the antiretroviral Efavirenz’s (EFZ) Active Pharmaceutical Ingredient (API). The method was based on quantitative NMR spectroscopy (qNMR). Methods: A Bruker Avance spectrometer (11.7 Tesla, 500 MHz for 1H) with a 5mm probe was used. The 1H-NMR signal at 7.54 ppm corresponding to the analyte of interest was employed to quantify the drug. The method was validated for specificity, selectivity, intermediate precision, linearity, range of work, accuracy, and robustness. Results: The method developed was specific and linear (r2 = 0.9998) with a value between 4.30 mg/mL and 12.40 mg/mL. The relative standard deviation for accuracy and precision was 0.4% or less. The method's robustness was demonstrated by changing four different parameters, and the difference among each was 1.2% or less. The results of this work have been found to be in agreement with those obtained from High-performance Liquid Chromatography (HPLC) analysis. result: The method developed was specific and linear (r2 = 0.9998) between 4.30 mg/mL and 12.40 mg/mL. The relative standard deviation for accuracy and precision was 0.4% or less. The method's robustness was demonstrated by changing four different parameters; the difference among each was 1.2% or less. The results in this work agreed with those obtained from high-performance liquid chromatography analysis (HPLC). Conclusion: The proposed method has been found to be a valuable and practical tool for quality control. Its applicability to determining many APIs and saving solvent use and time is highlighted.

Hydrogen-rich syngas upgrading via CO2 adsorption by amine-functionalized Cu-BTC: the effect of different amines.

Syngas produced from supercritical water gasification typically contain a high amount of CO2 along with H2. In order to improve the quality of syngas, amine-functionalized copper benzene-1,3,5-tricarboxylate (Cu-BTC) was synthesized as an effective adsorbent for selective removal of CO2 from syngas to increase the concentration of H2. The amines used in this study included monoethanolamine (MEA), ethylenediamine (EDA), and polyethyleneimine (PEI). The fundamental physicochemical character of adsorbents, CO2 adsorption capacity, and CO2/H2 selectivity were analyzed. The physicochemical characterization indicated that the structure of amine-functionalized Cu-BTC was partially damaged, which resulted in a decrease in specific surface area and pore volume. On the other hand, the enlarged pore size was beneficial for the mass transfer of gas in the adsorbent. Among these adsorbents, Cu-BTC/PEI exhibited the maximum CO2 adsorption capacity of 3.83mmol/g and the highest CO2/H2 selectivity of 19.74. It was found that the adsorption pressure is the most significant factor for the CO2 adsorption capacity. Lower temperature and higher pressure were favored for CO2 adsorption capacity and CO2/H2 selectivity, so physical adsorption by Cu-BTC played a dominant role. Moreover, Cu-BTC/PEI can be well-regenerated with stable adsorption efficiency after five consecutive cycles. These findings suggested that Cu-BTC/PEI could be a promising alternative adsorbent for CO2 capture from syngas.

Amyloid-like Aggregation of Wheat Gluten and Its Components during Cooking: Mechanisms and Structural Characterization.

Amyloid-like aggregation widely occurs during the processing and production of natural proteins, with evidence indicating its presence following the thermal processing of wheat gluten. However, significant gaps remain in understanding the underlying fibrillation mechanisms and structural polymorphisms. In this study, the amyloid-like aggregation behavior of wheat gluten and its components (glutenin and gliadin) during cooking was systematically analyzed through physicochemical assessment and structural characterization. The presence of amyloid-like fibrils (AFs) was confirmed using X-ray diffraction and Congo red staining, while Thioflavin T fluorescence revealed different patterns and rates of AFs growth among wheat gluten, glutenin, and gliadin. AFs in gliadin exhibited linear growth curves, while those in gluten and glutenin showed S-shaped curves, with the shortest lag phase and fastest growth rate (t1/2 = 2.11 min) observed in glutenin. Molecular weight analyses revealed AFs primarily in the 10-15 kDa range, shifting to higher weights over time. Glutenin-derived AFs had the smallest ζ-potential value (-19.5 mV) and the most significant size increase post cooking (approximately 400 nm). AFs in gluten involve interchain reorganization, hydrophobic interactions, and conformational transitions, leading to additional cross β-sheets. Atomic force microscopy depicted varying fibril structures during cooking, notably longer, taller, and stiffer AFs from glutenin.

Purine, nucleoside, and DNA nitration by peroxynitrite: Mechanistic considerations

Nitro-oxidative stress affects DNA, leading to special chemical modifications of nucleobases and deoxyribose, impacting DNA integrity and stability. Because of the importance of the topic, the state of the knowledge on purine, nucleoside, and DNA nitration by the reactive nitrogen species peroxynitrite was reviewed. Following a description of the chemical and physicochemical characteristics of purines and peroxynitrite, purine nitro-oxidation and its products, the reaction mechanisms, and the recently reported kinetic behavior of 8-NitroGua formation are discussed. Moreover, novel computational studies report structural and conformational DNA changes resulting from the formation of guanine nitration products. Given the relevance of the subject, surprisingly few publications deal with this topic, even considering the past five years.

Synthesis and Characterization of a Magnetic Molecular Imprinted Polymer for Tetracycline Quantification in Food Samples

AbstractIn the present work, we synthesized and tested a magnetic molecularly imprinted polymer (mag‐MIP) sensor for the detection of tetracycline in food samples. High‐performance liquid chromatography (HPLC) and spectrofluorometry were employed for tetracycline determination. The mag‐MIP was polymerized on the surface of Fe3O4@SiO2 magnetic nanoparticles using the following substances: 4 mmol of methacrylic acid as the functional monomer, 20 mmol of ethylene glycol dimethacrylate (EGDMA) as the cross‐linking agent, 82.5 mg of benzoyl peroxide as the radical initiator, and 30 ml of acetonitrile as the solvent. The physicochemical characteristics of the proposed mag‐MIP, including adsorption capabilities and selectivity, were studied and compared with those of a magnetic non‐molecularly imprinted polymer (mag‐NIP). The analytical curve was constructed in the range of 1.0×10−5–8.0×10−5 mol L−1, LOD: 3.3×10−6, LOQ: 1.1×10−5 mol L−1. The results obtained from the adsorption analysis showed that the highest adsorption capacity of the mag‐MIP at equilibrium was 8.247 mg g−1 and that the tetracycline adsorption process followed the Langmuir adsorption isotherm model and pseudo‐second‐order reaction kinetics. The proposed mag‐MIP also exhibited good results when subjected to fluorescence analysis; an increase in tetracycline concentration resulted in an increase in the adsorption capacity, and this led to the effective removal of tetracycline with the reduction of fluorescence intensity. The applicability of the proposed mag‐MIP was evaluated in honey, cow milk, and egg samples through recovery tests conducted using samples containing spiked tetracycline concentration at two different concentration levels (1.7×10−5 and 2.5×10−5 mol L−1), where we obtained recovery percentages in the range of 73.2–87.2 % (HPLC) and 90.5–103.7 % (spectrofluorometry).

Physicochemical Characteristics of Water in the Bontanga Irrigation Dam in the Guinea Savannah Agro-Ecological Zone of Ghana

Fresh water resource is one of the most significant natural assets of a country. Irrigation dams are usually used for irrigation purposes and also often serve as a source of water for domestic use. Due to this, there is a need for proper maintenance, assessment, and sustainable use of irrigation dams. This study assessed the physicochemical properties of the water in the reservoir of Bontanga irrigation dam situated in the Guinea Savannah Agro-Ecological Zone of Ghana. The study assessed four (4) physical and fourteen (14) chemical water quality parameters of the water for irrigation to know whether they are within the acceptable threshold set by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO). Sampling techniques used in this study were stratified and purposive samplings. The reservoir of the dam was divided into nine (9) strata and in each stratum, 5 samples were taken making a total of 45 samples. Samples taken in each strata were composited making it a total of 9 samples. The water samples were collected into well-labelled polythene bottles and kept in an ice chest with ice cubes. The samples were transported to the Ecological Laboratory of the University of Ghana for analysis. The parameters analyzed were pH, electrical conductivity (EC), temperature, total dissolved solutes (TDS), chloride (Cl-), sulphate (SO42-), bicarbonate (HCO3-), carbonate, PO4-P, nitrites/nitrate (NO3-N), total dissolved solids (TDS), magnesium (Mg2+), calcium (Ca2+), sodium (Na+), boron, total alkalinity, ammonia (NH4-N) and potassium (K+). A greater percentage of the results obtained were within acceptable limits except potassium which was slightly higher. This could be the result of farming activities in the catchment of the dam. In general, the water in Bontanga irrigation dam can be considered suitable for irrigation purposes.

Phylum-level studies of bacterial cutinases for unravelling enzymatic specificity toward PET degradation: an in silico approach.

The overwhelming use of PET plastic in various day-to-day activities led to the voluminous increase in PET waste and growing environmental hazards. A plethora of methods have been used that are associated with secondary pollutants. Therefore, microbial degradation of PET provides a sustainable approach due to its versatile metabolic diversity and capacity. The present work highlights the cutinase enzyme's role in PET degradation. This study focuses on the bacterial cutinases homologs screened from 43 reported phylum of bacteria. The reported bacterial cutinases for plastic degradation have been chosen as reference sequences, and 917 sequences have shown homology across the bacterial phyla. The dienelactone hydrolase (DLH) domain was identified for attaining specificity towards PET binding in 196 of 917 sequences. Various computational tools have been used for the physicochemical characterization of 196 sequences. The analysis revealed that most selected sequences are hydrophilic, extracellular, and thermally stable. Based on this analysis, 17 sequences have been further pursued for three-dimensional structure prediction and validation. The molecular docking studies of 17 selected sequences revealed efficient PET binding with the three sequences derived from the phylum Bacteroidota, the lowest binding energy of -5.9kcal/mol, Armatimonadota, and Nitrososphaerota with -5.8kcal/mol. The two enzyme sequences retrieved from the phylum Bacteroidota and Armatimonadota are metagenomically derived. Therefore, the present studies concluded that there is a high probability of finding cutinase homologs in various environmental resources that can be further explored for PET degradation.

On Tautomerism and Amphoterism: An In-Depth Structural and Physicochemical Characterization of Ammeline and Some of Its Salts.

Ammeline is a simple, readily available, molecular compound, which has been known for nearly 200 years. Despite that, no proper structural characterization of ammeline has been conducted so far. For this reason, the prevalent tautomeric form of ammeline in the solid remained unknown to this date. In the course of this study, its crystal structure was finally established by single-crystal X-ray diffraction. In this structure, ammeline is exclusively found as its 4,6‑diamino-1,3,5-triazin-2(1H)-one tautomer and adopts layered structure with an exceptionally high hydrogen bond density. Ammeline shows an interesting amphoteric behavior. Therefore, the synthesis and structural characterization of some of its salts were carried out to investigate the influence of the protonation degree on its molecular structure. In particular, the crystal structure of silver ammelinate monohydrate was solved as the first reported structure containing deprotonated ammeline. Moreover, the crystal structures of three different modifications of ammelinium perchlorate were elucidated and the transformation conditions between them were studied. Lastly, the crystal structure of ammelinediium diperchlorate monohydrate, containing unprecedented doubly protonated ammeline, was determined. The products' thermal behavior was studied by differential thermal analysis and thermogravimetric analysis. The perchlorate salts were additionally examined for their potential as insensitive high-energy-density materials.