Hydrochloric Research Articles

Optimization and Kinetic Study of Manganese Leaching from Pyrolusite Ore in Hydrochloric Acid Solutions with Oxalic Acid

AbstractThe leaching behavior of pyrolusite minerals was examined in hydrochloric acid solutions, including oxalic acid, to evaluate the influence of various experimental conditions. The optimum parameters for the leaching process were found in the first stage, and the process's kinetics were assessed in the second. The concentrations of oxalic acid, hydrochloric acid, and temperature were chosen as independent variables in the optimization experiments, with the central composite design used to analyze the experimental data. The optimum concentrations for oxalic acid, hydrochloric acid, and temperature were determined to be 0.75 mol/L, 1.2 mol/L, and 60 °C, respectively. The leaching rate was determined to be 97.4% for 120 min of response time in optimum situations. The kinetic assessment experiments studied the effects of solid/liquid ratio, particle size, stirring speed, and temperature on the manganese leaching rate from pyrolusite. In the studies, the leaching rate was shown to rise with increasing temperature and stirring speed, as well as with decreasing particle size and solid/liquid ratio. The kinetic analysis revealed that the leaching kinetics matched the mixed kinetic model, and a mathematical model for the leaching process was developed. This process's activation energy was determined to be 29.05 kJ/mol. Graphical Abstract

A study on inhibition efficiency of (-)-corey lactone diol as corrosion inhibitor for low carbon steel, in hydrochloric acid: Surface characterisation and quantum studies

A study on inhibition efficiency of (-)-corey lactone diol as corrosion inhibitor for low carbon steel, in hydrochloric acid: Surface characterisation and quantum studies

Development of a GC-MS Method for the Analysis of Selected Opioids in Human Hair Samples

Background: Hair samples are recognized as alternative biological specimens in forensic and clinical toxicology for detecting drug abuse and poisoning. Forensic testing for opioids in hair has become a useful diagnostic measure for assessing chronic drug usage through segmental analysis. However, accurate, sensitive and specific analytical methods are needed. The aim of this study was to introduce a simple, sensitive and specific GC-MS method for the identification and quantitation of selected and commonly abused opioids (tramadol, methadone, morphine, and codeine) in hair samples. Methods: After external decontamination, a 50 mg portion of powdered hair sample was combined with hydrochloric acid (0.1 M) and incubated on a magnetic stirrer at 56°C for 16 hours. Then, 1 mL of sodium hydroxide (0.1 M) and 2 mL of phosphate buffer (1 M, pH=8.4) were added. Chloroform-isopropanol (ratio: 80:20 V/V) was utilized as the extracting solvent and the sample was homogenized and centrifuged for 5 minutes (at 3500 rpm). After centrifugation, the organic phase was dried using dry nitrogen gas. The sample was derivatized with N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA). The blank, standards, and real samples were subsequently analyzed by GC-MS.Results: The limits of detection in the linearity experiments ranged from 0.12 to 0.21 ng/mg. According to the validation results, the method exhibited linearity in the concentration range of 0.1-2.5 ng/mg for all analytes, with calibration curve slopes ranging from R2=0.98 to 0.99. Good inter and intra-day precision relative standard deviations (RSDs) were observed to be <3.5% for all compounds. Extraction efficiency varied from 91.8 to 102.4%. Conclusion: The validation and analysis of actual samples indicate that this method is straightforward, sensitive, and specific for the analysis of opioids in routine hair analysis.

Process optimization in the pyroconversion of native sweet potato starch: structural and functional characterization of pyrodextrin

This work aims to produce dextrin from sweet potato (Ipomoea batatas) starch by pyroconversion. The effect of dextrinization process (roasting time, temperature, and hydrochloric acid concentration) on properties (structural and functional) of starch have been studied using central composite design of experiment. Reaction conditions included: roasting time (55 and 94 min), temperature (127 and 152 °C), and hydrochloric acid concentration (0.17 and 0.43 M). The temperature (quadratic effect X22) is highly significant on the three measured responses (p < 0.05) (Color Index (CI), Turbidity (Turb), and Saccharification Percentage (SP)). Also, the findings indicated that the two most important parameters influencing the pyroconversion of sweet potato starch in the current study were temperature (X2) and hydrochloric acid concentration (X3). The optimal conditions for dextrin production obtained are 94 min, 127 °C and 0.43 M for roasting time, temperature, and hydrochloric acid concentration respectively having 97% of solubility. The FTIR analysis revealed that OH, C-H, C-O, C–C and C-O–H were the main functional groups. These functional groups remained unaffected by the pyroconversion, since the bands extend and the spectrums of all native and pyrodextrin were similar. X-Ray Diffractometry analysis results of dextrin showed that the thermal treatment reduces the crystallinity of starch. Also, this analysis shows starch has CA-type XRD patterns. Scanning Electron Microscopy (SEM) analysis results showed that the defined optimal production maintains the morphology of starch. Differential scanning calorimetry (DSC) used for thermal analysis helps to obtain the glass transition temperature of modified starch equals to 139 °C. Optimal conditions of production of pyrodextrins from sweet potato granule starches could be easily produced with improved physicochemical properties to be used as encapsulating agent or additives in food and chemical industries.

Multi-functional properties of lactic acid bacteria strains derived from canine feces

IntroductionProbiotics, especially Lactic Acid Bacteria (LAB), can promote the health of host animals in a variety of ways, such as regulating intestinal flora and stimulating the host’s immune system.MethodsIn this study, 206 LAB strains were isolated from 48 canine fecal samples. Eleven LAB strains were selected based on growth performance, acid and bile salt resistance. The 11 candidates underwent comprehensive evaluation for probiotic properties, including antipathogenic activity, adhesion, safety, antioxidant capacity, and metabolites.ResultsThe results of the antipathogenic activity tests showed that 11 LAB strains exhibited strong inhibitory effect and co-aggregation ability against four target pathogens (E. coli, Staphylococcus aureus, Salmonella braenderup, and Pseudomonas aeruginosa). The results of the adhesion test showed that the 11 LAB strains had high cell surface hydrophobicity, self-aggregation ability, biofilm-forming ability and adhesion ability to the Caco-2 cells. Among them, Lactobacillus acidophilus (L177) showed strong activity in various adhesion experiments. Safety tests showed that 11 LAB strains are sensitive to most antibiotics, with L102, L171, and L177 having the highest sensitivity rate at 85.71%, and no hemolysis occurred in all strains. Antioxidant test results showed that all strains showed good H2O2 tolerance, high scavenging capacity for 1, 1-diphenyl-2-trinitrophenylhydrazine (DPPH) and hydroxyl (OH−). In addition, 11 LAB strains can produce high levels of metabolites including exopolysaccharide (EPS), γ-aminobutyric acid (GABA), and bile salt hydrolase (BSH).DiscussionThis study provides a thorough characterization of canine-derived LAB strains, highlighting their multifunctional potential as probiotics. The diverse capabilities of the strains make them promising candidates for canine dietary supplements, offering a holistic approach to canine health. Further research should validate their efficacy in vivo to ensure their practical application.

Synthesis and characterization of enhanced azo-azomethine doped PANI/HCl conducting polymers for electrochemical applications

In this study, conducting polymers composed of polyaniline hydrochloric acid (PANI/HCl) with varying concentrations of a newly synthesized azo-azomethine dye (4-(((Z)-2-hydroxy-5-((Z)-(4-hydroxyphenyl)diazenyl)-3-methoxybenzylidene)amino)benzoic acid) were synthesized using a chemical oxidative polymerization technique. The synthesized azo-azomethine was characterized by FTIR, 1H-NMR, 13C-NMR, and HRMS. The effects of varying the concentration of the dopant azo-azomethine in PANI/HCl on its optical, structural, thermal, and electrical properties were examined using FTIR, UV–Vis, XRD, FESEM, TEM, cyclic voltammetry, and electrical impedance spectra. The results indicate that the optical, direct, and indirect band gaps of the doped polymers decreased from 4.48 and 3.96 eV to 3.91 and 2.49 eV, respectively. The crystalline structure and phase transitions in the doped polymers were examined using X-ray diffraction. Cyclic voltammetry demonstrated that the doped polymers exhibited higher electrochemical conductivity compared to the pure polymer, with the specific capacitance increasing from 161.17 to 816.9 F/g. The electrical impedance spectra revealed the bulk resistance and conductivity of the material. Among all the doped polymers, PANI/HCl with an azo-azomethine concentration of 5 × 10−5 M exhibited lower bulk resistance (10 Ω) and higher electrical conductivity (σ = 50.09 × 10−3 S cm−1).

Assessment of 5-Hydroxymethylfurfural in Food Matrix by an Innovative Spectrophotometric Assay

Foods contaminants pose a challenge for food producers and consumers. Due to its spontaneous formation during heating and storage, hydroxymethylfurfural (HMF) is a prevalent contaminant in foods rich in carbohydrates and proteins. Colorimetric assays, such as the Seliwanoff test, offer a rapid and cost-effective method for HMF quantification but require careful optimization to ensure accuracy. We addressed potential interference in the Seliwanoff assay by systematically evaluating parameters like incubation time, temperature, and resorcinol or hydrochloric acid concentration, as well as the presence of interfering carbohydrates. Samples were analyzed using a UV–Vis spectrophotometer in scan mode, and data obtained were validated using HPLC, which also enabled quantification of unreacted HMF for assessing the protocol’s accuracy. Incubation time and hydrochloric acid percentage positively influenced the colorimetric assay, while the opposite effect was observed with the increase in resorcinol concentration. Interference from carbohydrates was eliminated by reducing the acid content in the working reagent. HPLC analyses corroborated the spectrophotometer data and confirmed the efficacy of the proposed method. The average HMF content in balsamic vinegar samples was 1.97 ± 0.94 mg/mL. Spectrophotometric approaches demonstrated to efficiently determine HMF in complex food matrices. The HMF levels detected in balsamic vinegars significantly exceeded the maximum limits established for honey. This finding underscores the urgent need for regulations that restrict contaminant levels in various food products.

Insights into corrosion inhibition of aluminum in hydrochloric acid solutions using expired cephalosporins and klavox: Chemical, electrochemical and theoretical approaches

The inhibitory efficacy of two expired antibiotic drugs namely, cephalosporin and klavox against corrosion of aluminum in 1.0 M HCl solution was investigate utilizing potentiodynamic polarization (PDP) impedance spectroscopy (EIS) and weight reduction (WR) methodologies. It was discovered that the two expired drugs act as excellent inhibitors and the inhibition efficacy increases as the drug concentration increases and the temperature decreases. The inhibition efficacy reached 97.62 % and 99.42 % at 900 ppm of cephalosporin and klavox at 298 K, respectively. Expired drugs act as a mixed type inhibitor, controlling primarily the anodic and cathodic process, as evidenced by the PDP curves. According to EIS analysis, the charge transfer resistance values increased with increasing inhibitor concentration. The adsorption isotherm demonstrates that the expired drugs become active by physical adsorption on the Al surface, and their adsorption obeys the Langmuir isotherm. Through quantum chemistry calculations, the relationship between the inhibition properties and molecular structure was studied.

Does Sn2+ play well with Zn2+ as their molten chloride salts react with Cr–Al–B MAB phase?

Novel Zn-MAX phases like Ti2ZnC were synthesized in the literature by the reaction between Lewis acid salts like ZnCl2 and the MAX phase. The interactions between the Cr–Al–B MAB phase contained in the PLS coating formed during HDA of Fe–Cr–B cast steel and five types of molten chloride salts (ZnCl2 and SnCl2) were investigated. The results showed that the Cr-(Al, Zn)–B and Cr-(Al, Sn)–B MAB phase solid solution were formed as the PLS coating reacted with the molten ZnCl2 and SnCl2, respectively, through topochemical reaction. Zn and Sn could not coexist in the A-site Cr–Al–B MAB phase solid solution, and the replacement ability of Sn2+ contained in molten salt was much stronger than that of Zn2+. Zn and Sn whiskers could spontaneously grow on the Cr-(Al, Zn)–B and Cr-(Al, Sn)–B MAB phase solid solution respectively.

Safety assessment of the substances 'wax, rice bran, oxidised' and 'wax, rice bran, oxidised, calcium salt' for use in food contact materials.

The EFSA Panel on Food Contact Materials (FCM) assessed the safety of the substances 'wax, rice bran, oxidised' and 'wax, rice bran, oxidised, calcium salt', used as additives up to 0.3% in polyethylene terephthalate (PET), polyamide (PA), thermoplastic polyurethane (TPU), polylactic acid (PLA) and poly(vinyl chloride) (PVC) in contact with all food types for long-term storage at room temperature and below, after hot-fill and/or heating. The substances consist of the chemical classes wax esters, carboxylic acids, alcohols and calcium salts of acids, along with an unidentified organic fraction up to ■■■■■ w/w. Migration into 10% ethanol and 4% acetic acid was below 0.012 mg/kg for each chemical class, and about 0.001 mg/kg for the unidentified fraction. In isooctane, migration was up to 0.297 mg/kg food for wax esters, below 0.01 mg/kg food for the other chemical classes and about 0.02 mg/kg food for the unidentified fraction. The contact with dry food and food simulated by 20% ethanol were considered covered by the migration tests with aqueous simulants. Based on genotoxicity assays and compositional analyses, the constituents of the chemical classes did not raise a concern for genotoxicity. The potential migration of individual constituents or groups of chemically-related compounds of the unidentified fraction would result in exposures below (for aqueous food) and above (for fatty food) the threshold of toxicological concern for genotoxic carcinogens. Therefore, the FCM Panel concluded that the substances are not of safety concern for the consumer, if used as additives up to 0.3% w/w in PET, PLA and rigid PVC materials and articles intended for contact with all food types except for fatty foods, for long-term storage at room temperature and below, including hot-fill and/or heating up to 100°C for up to 2 h.

Radiation reduction modification of sp2 carbon-conjugated covalent organic frameworks for enhanced photocatalytic chromium(VI) removal

A sp2 carbon-conjugated covalent organic framework (BDATN) was modified through γ-ray radiation reduction and subsequent acidification with hydrochloric acid to yield a novel functional COF (named rBDATN-HCl) for Cr(VI) removal. The morphology and structure of rBDATN-HCl were analyzed and identified by SEM, FTIR, XRD and solid-state 13C NMR. It is found that the active functional groups, such as hydroxyl and amide, were introduced into BDATN after radiation reduction and acidification. The prepared rBDATN-HCl demonstrates a photocatalytic reduction removal rate of Cr(VI) above 99% after 60 min of illumination with a solid-liquid ratio of 0.5 mg/mL, showing outstanding performance, which is attributed to the increase of dispersibility and adsorption sites of rBDATN-HCl. In comparison to the cBDATN-HCl synthesized with chemical reduction, rBDATN-HCl exhibits a better photoreduction performance for Cr(VI), demonstrating the advantages of radiation preparation of rBDATN-HCl. It is expected that more functionalized sp2 carbon-conjugated COFs could be obtained by this radiation-induced reduction strategy.

Electrochemical, microstructural and theoretical validation of 2-(2-Bromophenyl)-1H-benzimidazole as inhibitor for C1018 steel during very aggressive CO2 corrosion

This work is motivated by the lack of research papers reporting benzimidazole derivatives in very aggressive CO2-corrosion systems. We appraise the inhibitive performance of 2-(2-bromophenyl)-1H Benzimidazole (BPHB) in CO2-saturated 3.5% sodium chloride (NaCl) + 50 ppm acetic acid (HAc) without and with 1M hydrochloric acid (HCl) using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), scanning electron microscopy (SEM) and x-ray diffraction (XRD). We augment results from these techniques with molecular dynamics simulations and density functional theory, as computational modelling techniques. In the absence of HCl, the inhibitor adsorbs firmly on the steel surface, displays a strong cathodic influence on corrosion potential (Ecorr) and current density (icorr), and minimizes both general and pitting corrosion with ~ 80% efficiency. The presence of HCl furnishes abundant H+ ions that significantly diminish the cathodic influence of BPHB, blocks its firm adsorption and, although it reduces the extent of general and pitting corrosion, lowers its efficiency to ~ 70%. Computational modelling techniques confirm electrochemical and surface probe results. The nitrogen atoms and C=C bonds in the imidazole ring are the centers that facilitate BPHB adsorption. The inhibitor adsorbs in such a way as to maximize surface coverage. However, adsorption is more energetically favored in the absence of HCl, based on Eads calculations.

Analyte-dependent Rabi splitting in solid-state plexcitonic sensors based on plasmonic nanoislands strongly coupled to J-aggregates.

A key challenge in the field of plexcitonic quantum devices is the fabrication of solid-state, device-friendly plexcitonic nanostructures using inexpensive and scalable techniques. Lithography-free, bottom-up nanofabrication methods have remained relatively unexplored within the context plexcitonic coupling. In this work, a plexcitonic system consisting of thermally dewetted plasmonic gold nanoislands (AuNI) coated with a thin film of J-aggregates was investigated. Control over nanoisland size and morphology allowed for a range of plasmon resonances with variable detuning from the exciton. The extinction spectra of the hybrid AuNI/J-aggregate films display clear splitting into upper and lower hybrid resonances, while the dispersion curve shows anti-crossing behavior with an estimated Rabi splitting of 180 eV at zero detuning. As a proof of concept for quantum sensing, the AuNI/J-aggregate hybrid was demonstrated to behave as a plexcitonic sensor for hydrochloric acid vapor analyte. This work highlights the possibility of using thermally dewetted nanoparticles as a platform for high-quality, tunable, cost-effective, and scalable plexcitonic nanostructures for sensing devices and beyond.

Investigation of carbon dioxide absorption performance in amine amino acid salts for upgrading biogas applications: Blended absorbents of piperazine and amino acid solutions

BackgroundThe increasing amount of CO2 in the atmosphere is a critical environmental issue, necessitating the development of efficient CO2 capture technologies. Amine amino acid solutions (AAAS) have demonstrated potential in improving CO2 absorption and desorption. This study explores the efficiency of various AAAS, including piperazine (PZ), glycine (Gly), lysine (Lys), sarcosine (Sar), and alanine (Ala), under specific experimental conditions. MethodologyThe CO2 absorption and desorption processes were investigated using AAAS under conditions of 45 % CO2 at 313.15 K and with pure N2 at 353.15 K, respectively. The findings obtained for CO2 loading, regeneration rate, CO2 desorption heat, and 13C nuclear magnetic resonance (NMR) are valuable for understanding their impacts on the design and improvement of energy efficiency CO2 capture techniques. Furthermore, the physicochemical properties of PZ + lysine solutions such as density, viscosity, and vapor pressure were also measured at equimolar concentration ranges such as 0.75 M, 1.0 M, 1.25 M, and 1.5 M at T = 303.15 K to 353.15 K and 0.1 MPa pressure. Significant findingsThe study revealed significant enhancements in CO2 absorption and desorption with the addition of AAAS compared to monoethanolamine (MEA) solutions. Notably, among all the solutions, the PZ + lysine solution exhibited the maximum CO2 cyclic capacity at 0.792 mol CO2/mol absorbent, and the lowest regeneration heat. These findings provide valuable insights into the design and improvement of energy-efficient CO2 capture techniques.

The interaction of light with oxygen-vacancy-rich W18O49 nanoparticles synthesized using different acid molarities for acidic and neutral water treatments

Toxic industrial compounds as a global difficulty can adversely impact people's health and the environment which motivates studies on the interaction of light and metal oxide nanoparticles to treat the water through adsorption or photocatalysis mechanism by nanoparticles. In the paper, oxygen-vacancy-rich W18O49 nanorods are successfully synthesized by a facile one-pot hydrothermal method using different molarities of hydrochloric acid (HCl) (2–12 M) as proposed candidates to treat the wastewater and solve the global difficulty related to treating the acidic water. The results declare that the change in acid molarity leads to noteworthy changes in the characteristic properties of the produced W18O49 nanorods, and the lowest acid molarity (2 M) causes the formation of uniform and pure monoclinic W18O49 nanorods with the high specific surface area (SSA) of 51.33 m2/g. Furthermore, the nanorods exhibit indirect and direct band gap energies in the range of 2.52–2.68 eV and 2.54–3.08 eV, respectively, as influenced by varying acid molarities (2–12 M). Furthermore, the impressive effects of acid molarity on the methylene blue removal efficiency of the nanorods under ultraviolet (UV) light are observed. The highest efficiency is obtained for W18O49 nanorods synthesized using the acid molarity of 2 M which can be explained by its high SSA, small band gap energy, generation of a large number of electron-hole pairs, and its efficient charge separation. The efficiencies of water treatment reach up to 99 % and 99.5 % at pH of 7 and 5, respectively, which is an excellent achievement and leads to proposing the mentioned W18O49 nanorods as an excellent candidate for treating wastewater and acid factory effluent which represents an appreciable breakthrough in addressing the issue.

Determination of amphetamines in hair samples using microextraction by packed sorbent and gas chromatography-mass spectrometry.

Several protocols for the analysis of amphetamine-type stimulants (ATS) in hair have been developed over the years, with microextraction by packed sorbent (MEPS) being used for drugs like opiates, cocaine and ketamine. However, concerning ATS determination in hair samples, this approach has only been applied so far to amphetamine (AMP) and methamphetamine (MAMP). This study aimed at developing and validating a MEPS-based procedure for the determination in hair of not only AMP and MAMP but also of 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 1-(1,3-benzodioxol-5-yl)propan-2-yl (ethyl)amine (MDE) and N-methyl-1-(1,3-benzodioxol-5-yl)-2-aminobutane (MBDB) as well. Hair, 50 mg, was incubated with 1M sodium hydroxide (NaOH) at 45°C overnight, neutralization with 10M hydrochloric acid (HCl) and centrifugation followed. The design of experiments approach was used for MEPS optimization, with the final optimized conditions including conditioning (250 μL methanol and deionized water), loading (18 × 100 μL) and elution (7× 100 μL 2% NH4OH in acetonitrile). The eluted extract was evaporated to dryness and underwent microwave-assisted derivatization with N-methyl-bis(trifluoroacetamide) (MBTFA), and it was afterwards injected onto the gas chromatography-mass spectrometer (GC-MS). The obtained recoveries ranged between 8% and 14% for AMP, 14% and 20% for MAMP, 10% and 15% for MDA, 18% and 28% for MDMA, 25% and 43% for MDE and 34% and 52% for MBDB, and the method was linear from 0.2 to 5.0ng/mg. Precision and accuracy were in accordance with international method validation guidelines. This novel method involving MEPS coupled to GC-MS offers a swift, eco-friendly and cost-effective alternative to traditional procedures for detecting these AMPs in hair samples.

Electrochemical Coproduction of Hydrogen, Oxygen, Sodium Hydroxide, and Hydrochloric Acid from Brines via Direct Electrosynthesis with Chlorine Suppression

Electrochemical Coproduction of Hydrogen, Oxygen, Sodium Hydroxide, and Hydrochloric Acid from Brines via Direct Electrosynthesis with Chlorine Suppression

In vitro probiotic potential of lactic acid bacteria isolated from the intestines of Muscovy ducks.

The current study was conducted to isolate, test and characterize molecularly and physiologically lactic acid bacteria from the intestines of Muscovy ducks to evaluate their probiotic potential for poultry farming. Three hundred lactic acid bacteria from the gastrointestinal tract of Muscovy ducks were isolated. The strains were phenotypically characterized by observing cell morphology, performing Gram staining, catalase production, and testing their ability to grow in MRS broth at different temperatures, pH values, NaCl concentrations, bile concentration, and in compatibility tests between strains. Nine strains were selected based on their resilience. Eight strains were identified using molecular techniques. These strains exhibited significant tolerance to acidic pH, bile salts, and NaCl, essential for probiotic function. All isolates inhibited the growth of Salmonella enterica serotype Typhimurium (DT104) and Enteropathogenic Escherichia coli serotype O86:H34 (EPEC), showcasing their antimicrobial potential. Antibiotic susceptibility testing revealed 100% resistance to clindamycin and erythromycin but high susceptibility to ampicillin and vancomycin. Growth was observed at various temperatures, indicating mesophilic characteristics. Compatibility tests confirmed their suitability for probiotic formulations. Genomic analysis identified the strains primarily as Enterococcus. Conclusively, the study identified eight out of nine selected lactic acid bacteria strains from Muscovy ducks as autochthonous probiotics, showing resilience to treatments and compatibility for consortium formulation. These strains are suitable for in vivo testing for potential poultry farming applications. Further research on their molecular mechanisms and in vivo effects is needed.

In vitro assessment of probiotic potentials of yeast strains isolated from a cereal-based (Ogi)) traditional fermented food

This present research focused on the isolation of yeast strains from fermented African cereal-based food with promising probiotic attributes. Yeast isolates were obtained from a locally produced cereal-based food “Ogi” also known as Akamu. The yeast was evaluated for their stress tolerance (pH, bile, temperature, NaCl, gastric juice), adhesion properties (auto-aggregation, hydrophobicity) and susceptibility to antibiotics. The strains performed well at 37 °C and exhibited strong ability to tolerate acid (pH 3) and bile salt (1.5%) environment with a percentage survival range of 60-82.61% and 62.96-83.67% respectively. Candida tropicalis (A4) gave the highest salt tolerance at 1% (89.29) and 4% (92.86), while Saccharomyces cerevisiae (A2) showed greater ability to survive the stimulated gastrointestinal conditions at 42.86%. The strains exhibited high auto-aggregation (68.8-94.9%) and a good hydrophobicity to chloroform and toluene. Susceptibility profile of the yeast strains to antibacterial antibiotics showed that all the yeasts presented a resistance pattern. These results indicate that C. tropicalis and S. cerevisiae both have the capability to serve as probiotic agents and can be proposed for various applications. Also, fermented cereal-based Ogi with its wide array of health benefits can serve as a carrier for the delivery of probiotics to both animals and humans as food supplements.

Chlorine-Modified Soluble Melem-Based Graphitic Carbon Nitrite: Facile Synthesis, Catalytic Property and Ultrafast 2D IR Spectroscopic Characterization.

On the basis of thermal etching bulk graphitic carbon nitride (g-C3N4), a mild hydrochloric acid treatment method was used in this work to produce g-C3N4 nano-sheets (CNNS) and further carbon nitride with chloride-modification (CNCl). The latter has thinner layer and smaller particle size and exhibit greatly improved dispersibility and solubility in water, DMSO and other polar solvents. A typical photocatalytic reaction in solution driven by CNCl shows a significantly improved photocatalytic performance over bulk g-C3N4 and CNNS. Steady-state analytical tools including SEM, mass, UV-Vis and IR spectroscopies, and time-resolved two-dimensional infrared (2D IR) vibrational spectroscopy, were used together in this work. Better solubility, more flexible structure, smaller size, easier generation of free radicals and lower recombination rate of electron-hole pair, are believed to be reasons for the superior photocatalytic performance of CNCl.