Determination of alkalinity in the water sample: a theoretical approach

Fresh potable water is an indispensable drink which humans consume daily in substantial amounts. Nonetheless, very little is known about the composition of the microbial community inhabiting drinking water or its impact on our gut microbiota. In the current study, an exhaustive shotgun metagenomics analysis of the tap water microbiome highlighted the occurrence of a highly genetic biodiversity of the microbial communities residing in fresh water and the existence of a conserved core tap water microbiota largely represented by novel microbial species, representing microbial dark matter. Furthermore, genome reconstruction of this microbial dark matter from water samples unveiled homologous sequences present in the faecal microbiome of humans from various geographical locations. Accordingly, investigation of the faecal microbiota content of a subject that daily consumed tap water for 3 years provides proof for horizontal transmission and colonization of water bacteria in the human gut.

This work evaluates the efficiency of SiO2-coated Fe3O4 magnetic nanoparticles (SMNPs) for adsorption of methyl orange (MO). Adsorption of MO on the studied nanoparticle was developed for removal, preconcentration and spectrophotometric determination of trace amounts of it. To find the optimum adsorption conditions, the influence of pH, dosage of the adsorbent and contact time was explored by central composite design. In pH 2.66, with 10.0 mg of the SMNPs and time of 30.0 min, the maximum adsorption of MO was obtained. The experimental adsorption data were analyzed by the Langmuir and Freundlich adsorption isotherms. Both models were fitted to the equilibrium data and the maximum monolayer capacity qmax of 53.19 mg g−1 was obtained for MO. Moreover, the sorption kinetics was fitted well to the pseudo-second-order rate equation model. The results showed that desorption efficiencies higher than 99 % can be achieved in a short contact time and in one step elution by 2.0 mL of 0.1 mol L−1 NaOH. The SMNPs were washed with deionized water and reused for two successive removal processes with removal efficiencies more than 90 %. The calibration curve was linear in the range of 10.0–120.0 ng mL−1 for MO. A preconcentration factor of about 45 % was achieved by the method.

In the present work, Mn‐doped CuO‐NPs‐AC was prepared by a simple method, characterized using various techniques such as FESEM, EDX, XRD, PSD, and pHpzc and finally used for the adsorption of malachite green (MG) and methyl orange (MO) in a number of single and binary solutions. A series of adsorption experiments were conducted to investigate and optimize the influence of various factors (such as different pH, concentration of MG and MO, adsorbent mass, and sonication time) on the simultaneous adsorption of MG and MO using response surface methodology. Under optimal conditions of pH 10, adsorbent dose of 0.02 g, MG concentration of 30 mg L−1, MO concentration of 30 mg L−1, and sonication time of 4.5 min at room temperature, the maximum predicted adsorption was observed to be 100.0%, for both MG and MO, showing that there is a favorable harmony between the experimental data and model predictions. The adsorption isotherm of MO and MG by Mn‐doped CuO‐NPs‐AC could be well clarified by the Langmuir model with maximum adsorption capacity of 320.69 mg g−1 and 290.11 mg g−1 in the single solution and 233.02 mg g−1 and 205.53 mg g−1 in the binary solution by 0.005 g of adsorbent mass for MG and MO, respectively. Kinetic studies also revealed that both MG and MO adsorption were better defined by the pseudo‐second order model for both solutions. In addition, the thermodynamic constant studies disclosed that the adsorption of MG and MO was likely to be influenced by a physisorption mechanism. Eventually, the reusability of the Mn‐doped CuO‐NPs‐AC after six times showed a reduction in the adsorption percentage of MG and MO.

In this study, functionalized magnetic nanoparticles of poly (ionic liquid) 1-allyl-3-methylimidazolium chloride were prepared through free radical copolymerization method and tested as a high efficient adsorbent for the removal of anionic dyes in water samples. The physical and chemical structure of prepared magnetic nanoparticles (MNPs) were investigated using Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Next, synthesized magnetic nanoparticles were used in magnetic solid phase extraction (MSPE) method to extract three anionic dyes (Alizarin Red S, Congo Red and Methyl Orange) in water samples. Also, the effect of several parameters such as pH, temperature, contact time and amount of adsorbent was investigated and the optimum values were determined. In addition, the adsorbent has a high ability to remove anionic dyes from water samples containing different dyes. Limit of detection (LOD), limit of quantitation (LOQ), and correlation coefficient were determined for methyl orange, Congo red and alizarin red S dyes under optimum conditions. The synthesized magnetic nanoparticles can be collected by an external magnetic field and regenerated with an alkaline solution (NaOH) and reused. The obtained results showed that the MNPs@PIL method was very efficient and successful in removing dye pollutants in water samples.

In this report, a genome-scale reconstruction of Bacillus subtilis metabolism and its iterative development based on the combination of genomic, biochemical, and physiological information and high-throughput phenotyping experiments is presented. The initial reconstruction was converted into an in silico model and expanded in a four-step iterative fashion. First, network gap analysis was used to identify 48 missing reactions that are needed for growth but were not found in the genome annotation. Second, the computed growth rates under aerobic conditions were compared with high-throughput phenotypic screen data, and the initial in silico model could predict the outcomes qualitatively in 140 of 271 cases considered. Detailed analysis of the incorrect predictions resulted in the addition of 75 reactions to the initial reconstruction, and 200 of 271 cases were correctly computed. Third, in silico computations of the growth phenotypes of knock-out strains were found to be consistent with experimental observations in 720 of 766 cases evaluated. Fourth, the integrated analysis of the large-scale substrate utilization and gene essentiality data with the genome-scale metabolic model revealed the requirement of 80 specific enzymes (transport, 53; intracellular reactions, 27) that were not in the genome annotation. Subsequent sequence analysis resulted in the identification of genes that could be putatively assigned to 13 intracellular enzymes. The final reconstruction accounted for 844 open reading frames and consisted of 1020 metabolic reactions and 988 metabolites. Hence, the in silico model can be used to obtain experimentally verifiable hypothesis on the metabolic functions of various genes.

SAXS Ensemble Refinement of ESCRT-III CHMP3 Conformational Transitions

In this research, nickel ferrite (NiFe2O4) nanoparticles (NFNs) are prepared through coprecipitation method, and applied for adsorption removal of a model organic pollutant, methyl orange (MO). The characterization of the prepared NFNs was performed using scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM). Optimization and modeling of the removal of MO applying NFNs were performed via central composite design (CCD) and the influential parameters including nano-sorbent amount, dye initial concentration, contact time and pH were considered as input variables for CCD. A dye removal percentage of 99 % was achieved under the optimum condition established for MO removal that was in agreeing with the predicted value. Additionally, multi-layer artificial neural network (ML-ANN) was applied to acquire a predictive model of MO removal. The isothermal investigation of MO adsorption was performed by developing Langmuir, Freundlich and Temkin models, and results showed that experimental data were best fit in Freundlich model. Based on the adsorption kinetics studies, the pseudo-second-order kinetic model was the best model to describe the adsorption mechanism of MO onto NFNs.

This study reports the concentrations of organic pollutants, nutrients, and some physicochemical parameters in water samples from Vlora Port. Organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAH) and BTEX (Benzene, Toluene, o-, m- and p-Xyelenes, Ethylbenzene) were analyzed organic pollutants. The levels of NO3-, NO2-, NH4-, N-total, PO4-, and P-total were determined. Temperature, PH, Conductivity, Turbidity, TDS, TSS DO, BOD and COD were physical-chemical parameters determined in the water samples. Vlora Port is located in the southern part of Albania in Vlora Bay, near Vlora City in the Adriatic Sea. Elevated activities in port areas (terrestrial and marine areas) are the main causes of water pollution. Urban pollution, agriculture, and water currents can influence marine water pollution in this area. To evaluate pollution levels at the port of Vlora, water samples (12 stations) were analyzed over a two-year period (2022 – 2023). Water samples were collected during two seasons: March and July of each year Analyses of organic compounds were performed using a gas chromatograph (Varian 450 GC) equipped with ECD and FID detectors. Nutrients were analyzed using the UV-VIS technique. Titration, automatic, semi-automatic, and gravimetric methods were used to determine the physicochemical parameters. Organic pollutants were detected in all the water samples. Nutrient concentrations and physicochemical values classified the marine water of Vlora’s port as moderately good. Levels of organic pollutants, nutrients, and physicochemical parameters in water samples from Vlora’s port were higher/comparable with those reported in previous studies of the Adriatic Sea (Albania coastline).

Electrochemical remediation of methyl orange over reusable biochar ferrite coated photocatalytic plates

In this article we discuss the features of detection of microconcentration toxicants (ammonia, butanol-2, toluene) in natural waters with different salt concentration using the piezoelectric crystal quartz microbalance on gas analyzer “MAG-8” with injection input of sample. The samples of sea water were classified into groups by values of electro conductivity, total mineralization and hardness. Piezoelectric microbalance of equilibrium gas phase over sea water samples carried out in eight-sensors chamber (electrodes modifiers – multilayer carbon nanotubes, propolis (bees wax), polyethylene glycol 2000, polyethylene glycol sebacate, dinonylphthalate, three octylphosphate, methyl orange with polystyrene, Triton X-100) in static condition. The electrodes modifiers were chosen by criteria of minimal sensitivity to water vapors and different (crossing) sensitivity to vapors of anthropogenic pollutants. The primary analytical information of sensors array is integral characteristic of gases mixtures over water sample – “visual print” of sensors. It has been shown the dependence of “visual print” square of sensors array responses on concentration salts and electro conductivity of sea water samples. Using the methods of additives it is established the behavior of influence the microconcentarion of ammonia, butanol-2, toluene on summary indicator of sensor array. The possibility of toxicant identification in model solutions using selected identification parameters Aij is demonstrated. It has been shown the classification of sea water samples with toxicants additives by parameters of sorbtion efficiency and optimization of piezosensors array for analysis of natural water using the processing of sensors output data by principal component analysis. The most significant to separation of water samples with toxicant there are responses of sensors with films from polyethylene glycol sebacate, dinonylphthalate, three octylphosphate, and the electro conductivity of natural water is less significant.

Synthesis of zinc oxide nanoparticles–chitosan for extraction of methyl orange from water samples: Cuckoo optimization algorithm–artificial neural network

Fabrication of magnetic microsphere-confined graphene for the preconcentration of some phthalate esters from environmental water and soybean milk samples followed by their determination by HPLC

In this paper, a novel evacuated tube solar collector (ETSC) is first designed and built. Then, the impact of adding reflector, reflector plus single-axis sun tracker and reflector plus two-axis sun tracker to the built ETSC on the thermal efficiency of the ETSC is evaluated both theoretically and experimentally. In this regard, four identical versions of the proposed ETSC have been built and utilized in four collectors built and presented in this research work. The first collector is the same proposed built ETSC, the second collector is a parabolic trough solar collector comprising one built ETSC and a reflector (ETSC+R), the third collector is composed of one built ETSC, a reflector and a single-axis sun tracker all built in this study (ETSC+R+ ST), and the fourth collector consists of one built ETSC, a reflector and a two-axis sun tracker all built in this study (ETSC+R+ DT). Theoretical basis and concepts of the four collectors are formulated and analyzed in separate subsections. Theoretical results are outlined and highlighted at the end of each subsection. Experimental measurements and data obtained from the operation of the four collectors in the four seasons are presented that point by point verify theoretical results obtained in this study. To provide a comprehensive view, a techno-economic numerical comparison is performed between the four collectors. The following points, which are also the novelty and contributions of this work, are deduced from theoretical concepts, experimental data, and comparison provided in this study: •There is no technical and economic justification for adding a reflector to an ETSC that results in forming a parabolic trough solar collector (ETSC+R) without any sun tracker. •There is no economic justification for adding a single-axis sun tracker to a parabolic trough solar collector (ETSC+R). •There is no economic justification for adding a two-axis sun tracker to a parabolic trough solar collector (ETSC+R). •Comparing between a two-axis sun tracker and a single-axis sun tracker, adding the single-axis type to a parabolic trough solar collector (ETSC+R) is more advantageous.

Green synthesis of zinc oxide nanoparticles by Ziziphus jujuba leaves extract: Environmental application, kinetic and thermodynamic studies

The present research work outlines a low-cost and green electrochemical approach for the assay of ecological toxin catechol (CT) based on electro-polymerised methyl orange (MO)-activated carbon paste electrode (CPE) as a responsive, simple and low-priced electrocatalyst. The CT electrochemical response was premeditated on the surface of poly methyl orange-activated carbon paste electrode (Poly(MO)ACPE) using different voltammetric methods such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV) which recommends that the Poly(MO)ACPE shows good electrocatalytic nature for the electrochemical redox reaction of CT with high peak current response as associated to the bare carbon paste electrode (BCPE). The CT molecules expose electrochemical quasi-reversible reactions (oxidation and reduction nature) at Poly(MO)ACPE, which was done by a diffusion-controlled reaction kinetics. The practicability of this sensor was verified using the DPV method; here the CT peak current was improved with the varied concentration of CT in the range from 1.0 µM to 36.0 µM, and the corresponding limit of detection (LOD) and limit of quantification (LOQ) were 0.880 × 10−8 M and 2.935 × 10−8 M, respectively. The prepared sensor was efficiently tested with different interferents using the DPV method. Here, the sensor shows a lesser interference effect for the CT redox reaction nature. Finally, this sensor was applied for the analysis of CT in water and green tea samples, and the outcomes noticed a good CT recoveries.