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Ni(II), Cu(II), and Zn(II) complexes of the tridentate heterocyclic ligand, 2-(phenyl(pyridin-2-yl)methylene)hydrazine-1-carbothioamide (HL) have been synthesized and characterized by various spectroscopic techniques and elemental analyses. Infrared spectroscopy shows that the ligand coordinates to the metal ions through the azomethine and pyridine nitrogen atoms as well as the sulfur atom of the thioamide group to form a tridentate chelate system. In vitro screening of metal complexes against four bacterial strains (Staphylococcus aureus (ATCC 43300), Klebsiella pneumoniae (ATCC 700603), Methicillin resistant staphylococcus aureus (ATCC 33591), Shigella flexneri (NR 518)) and four fungal strains (Candida albicans (NR 29444), Candida albicans (NR 29445), Candida albicans (NR 29451), Candida krusei (HM 1122)) indicate that the Cu(II) complex showed good antibacterial activity on Methicillin resistant staphylococcus aureus (ATCC 33591) while the Zn(II) complex showed moderate activity against some of the bacterial and fungi strains. Antioxidant studies reveal that the complexes are more potent than the ligand to eliminate free radicals, with the Ni(II) complex showing the best free radical scavenger.

A composite material prepared by polymerization of β-cyclodextrin (β-CD) on the surface of natural hydroxyapatite using citric acid as cross linker, was employed as electrode material for the detection of Pb(II). Hydroxyapatite was obtained from bovine bones, following a three-step procedure including pre-calcination, chemical treatment with (NH4)2HPO4, and calcination. The structure and morphology of the pristine hydroxyapatite (NHAPP0.5) and its functionalized counterpart (NHAPp0.5-CA-β-CD) were examined using XRD, FTIR, and SEM. Upon deposition as thin film on a glassy carbon electrode (GCE), the ion exchange ability of NHAPp0.5-CA-β-CD was exploited to elaborate a sensitive sensor for the detection of lead. The electroanalytical procedure was based on the chemical accumulation of Pb(II) ions under open-circuit conditions, followed by the detection of the preconcentrated species using differential pulse anodic stripping voltammetry. The reproducibility of the proposed method, based on a series of 8 measurements in a solution containing 2 μM Pb(II) gave a coefficient of variation of 1.27%. Significant parameters that can affect the stripping response of Pb(II) were optimized, leading to a linear calibration curve for lead in the concentration range of 2 × 10−8 mol L−1 – 20 × 10−8 mol L−1 (R2 = 0.998). The detection limit (3S/m) and the sensitivity of the proposed sensor were 5.06 × 10−10 mol L−1 and 100.80 μA.μM−1, respectively. The interfering effect of several ions expected to affect the determination of lead was evaluated, and the proposed sensor was successfully applied in the determination of Pb(II) ions in spring water, well water, river water and tap water samples.

In this work, biomass lignocellulosic materials extracted via chemical and physical treatments from bean and pistachio pod waste were used for the optimized elimination of Indigo Carmine (IC) from aqueous medium, using a design of experiments methodology. The physicochemical properties of the studied materials (raw and treated counterparts) used for the sorption of IC were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with EDX, and thermal analysis. Key variables influencing the adsorption of IC, namely the initial IC concentration, the pH of the solution, the stirring time and the mass of adsorbents, were optimized by the central composite design (CCD) with three center points, the measured response being the amount of IC adsorbed. The optimal conditions obtained from the statistical analysis for the removal of IC were as follows: maximum adsorbed amounts of IC: 1.81 mg/g, 2.05 mg/g, 3.56 mg/g; 7.42 mg/g, 8.95 mg/g, 15.35 mg/g, for raw bean pods (RBS), BST1 and BST2 (bean pods chemically treated), and for raw pistachio pods (RPS), PST1 and PST2 (pistachio pods chemically treated), respectively. The pseudo-second-order nonlinear kinetics model well described the IC adsorption kinetics for RBS, BST1 and BST2, while the Elovich model was properly fitted by RPS, PST1, and PST2 biomaterials data. The Freundlich isotherm best described the shrinkage of IC on different sorbents. The good correlation of the experimental data of the IC with respect to the Freundlich isotherm indicated a multilayer adsorption with heterogeneous adsorption sites and different energies. The interest of this work consisted in developing analytical methods for the treatment of water polluted by dyes by using biosorbents, local biological materials widely available and inexpensive. The results collected in this work highlighted the interesting structural, morphological, and physico-chemical properties of the agro-waste used in the study, which properties allowed an important fixation of the target dye in solution. The research showed that the agro-waste used in the study are possible precursors to locally manufacture adsorbents at low cost, thus allowing the efficient removal of waste and dyes in liquid effluents.

Two novel copper complexes (1,2) with N,O-donor ligands were synthesized by reaction of copper(II) malonates with 3,3’-bis(pyrazolyl)pentane and 4,4’-trimethylenedipyridine in methanol at moderate temperature. These compounds were characterized by elemental analysis, UV-VIS, IR spectroscopies and powder X-ray diffraction analyses. Compound (1) melts at higher temperature (202°C) than compound (2) (100°C). The IR spectra showed typical vibrations related to C=N and C=C, characteristic of pyrazolyl and pyridine ligands.

A new chromium (III) coordination compound of 2-amino-3-carbomethoxy-4,5,6,7-tetrahydrobenzo[b]thiophene (ACTT) (3) with Cr(NO3)3.9H2O in methanol at room temperature for 48 hours has been prepared. The composition of the new complex compound (4) has been confirmed by a number of instrumental methods including IR, NMR, MS and elemental analysis. It was found that the ACTT ligand behaves as bidentate chelating agent and coordinates to the central metal ion through the nitrogen atom of the amino-group and the oxygen atom of the carbonyl function of the ester group. The results showed that in the coordination sphere of the complex, the metal ion is coordinated by three chelating ACTT ligands. In the structure of the cation core [Cr(ACTT)3]3+, the three ACTT ligands are linked to the chromium ion through three Cr-N and three Cr-O bonds forming a square bipyramidal geometry. The metal complex and the ACTT ligand were screened for their antimicrobial activities against several strains of bacteria (Staphylococcus aureus ATCC25923, Escherichia coli S2 (1), Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa ATCC27853, Shigella flexneri SDINT) and fungi (Candida albicans ATCC10231, Candida tropicalis PK233, Cryptococcus neoformans H99). The chromium complex showed promising antimicrobial activity against the microorganisms with minimum inhibitory values between 4 and 16 μg/mL.

In this work, 1,2-bis[4-(n-alkoxy)benzylidene]hydrazine (n-alkoxy: O(CH2)nH, n = 11–18 or 20), a symmetrical series of azines (linear compounds with rod-like shape structure), were synthesised using a very simple two-step procedure as a part of our continuing effort in evaluating hydrophobic 1,2-disubstituted hydrazine compounds as photoluminescent liquid crystalline materials. The first step of the synthesis involved the alkylation of the OH group of 4-hydroxybenzaldehyde in basic medium using the Williamson method to obtain 4-alkoxybenzaldehydes. While the second step included the condensation reaction of hydrazine hydrate and appropriately 4-alkoxybenzaldehydes compounds (mole ratio 1:2, respectively) in acidic medium under ambient conditions. The prepared compounds were characterised and their structures elucidated depending upon infrared (IR), ultraviolet-visible (UV–Vis), nuclear magnetic resonance (1HNMR, 13CNMR, DEPT NMR, 2D 1H-1H-COSY and 2D 1H-13C- HSQC) and elemental analysis (CHN). Liquid crystalline behaviour and photoluminescent properties were studied using polarised light optical microscopy (POM), fluorescence emissions (FE), differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD) techniques. The studies showed that all of these compounds are enantiotropic liquid crystalline materials exhibiting smectic (SmA and SmC) and nematic (droplet and thread) mesophases . The study also displayed that all of the prepared compounds are photoluminescent in the crystalline and liquid crystal states.

Olives stones and cotton cakes have been investigated as a cheap and available precursor used for the production of novel carbon using potassium hydroxide as chemical activating agent with 2:1 impregnation ratio at 1.5 M KOH. Carbonization was performed at 450°C for one hour. The activated carbons NOK and MK3 were characterized by Iodine Number, Fourier Transform Infrared (FTIR) spectroscopy, EDX Analysis, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) Analysis and Proximate Analysis (pHZCN, pH, volatile matter, fixed carbon). The effects of initial sorbate concentration and contact time on adsorption were evaluated. Errors analysis methods were used to evaluate the experimental data: Correlation coefficient (R2), chi-square (χ2), average relative error (ARE), sum of absolute errors (EABS) and root mean square error (RMSE) values were tested to find the best fitting isotherm. Elovich models provide the best fit in the uptake of 2,4-dinitrophenol by activated carbons NOK and MK3. Thus, among the isotherm models studied, it appears that the Dubinin-Radushkevich and Temkin (two parameters), Sips (three parameters) and Baudu (four parameters) models describe better the adsorption data. Error analysis showed that the models with two parameters better described the adsorption of 2,4-diniphenol data compared with the three parameter and four-parameter models. Key words: 2,4-dinitrophenol, activated carbon, cotton cake, olives stones, isotherms, kinetics.

A composite material prepared by polymerization of β-cyclodextrin (β-CD) on the surface of natural hydroxyapatite using citric acid as cross linker, was employed as electrode material for the detection of Pb(II). Hydroxyapatite was obtained from bovine bones, following a three-step procedure including pre-calcination, chemical treatment with (NH

Anamperometric sensor based on an inkjet-printed graphene electrode (IPGE) modified with amine-functionalized montmorillonite (Mt-NH2) for the electroanalysis and quantification of gentisic acid (GA) has beendeveloped. The organoclay used as IPGE modifier was prepared and characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, CHN elemental analysis, and thermogravimetry. The electrochemical features of the Mt-NH2/IPGE sensor were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The sensor exhibited charge selectivity ability which was exploited for the electrochemical oxidation of GA. The GA amperometric response was high inacidic medium (Brinton-Robinson buffer, pH 2) due to favorable interactions between the protonated amine groups and the negatively charged GA. Kinetic studies were also performed by cyclic voltammetry, and the obtained electron transfer rate constant of 11.3s-1 indicated a fast direct electron transfer rate of GA to the electrode. An approach using differential pulse voltammetry was then developed for the determination of GA (at + 0.233V vs. a pseudo Ag/Ag+ reference electrode), and under optimized conditions, the sensor showed high sensitivity, a wide working linear range from 1 to 21μM (R2 = 0.999), and a low detection limit of 0.33μM (0.051 ± 0.01mgL-1). The proposed sensor was applied to quantify GA in a commercial red wine sample. The simple and rapid method developedusing a cheap clay material could be employed for the determination of various phenolic acids.

This work describes a new sensitive sensor for the simultaneous electrochemical determination by square wave anodic stripping voltammetry of Cd2+ and Pb2+ ions in aqueous solution, based on a disposable ink-jet-printed graphene electrode (IPGE) modified by a thin film of montmorillonite (Mont) clay mineral. The clay was characterized by X-ray diffraction and scanning electron microscopy while the Mont–IPGE was analyzed by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry before its exploitation for sensing studies. EIS results revealed a low electron transfer rate on Mont–IPGE during the electro-oxidation of [Fe(CN)6]3−. The stripping response on both Cd2+ and Pb2+ analytes was improved by the in situ co-deposition with bismuth, added to the electrolyte solution, on the clay substrate. The proposed electrode showed great stability and good reproducibility. The key experimental parameters governing the stripping analysis of Cd2+ and Pb2+ were optimized. A linear relationship between peak currents and concentrations of the analytes was obtained in the range from 0.01 to 0.21 µM, leading to detection limits of 0.42 nM for Cd2+and 1.14 nM for Pb2+ ions, respectively (S/N = 3). The sensitivities to Cd2+ and Pb2+ ions were 921.8 A cm−2 M−1 and 1960.8 A cm−2 M−1, respectively. The Mont–IPGE sensor was used for the quantification of lead and cadmium in a mineral water.

Orange albedo and its adsorption capacity towards bisphenol A (BPA) were studied. Adsorption experiments were conducted in batch mode at 25-55°C. Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and Fourier transform infrared (FTIR) spectroscopy were used to characterise the biosorbent. The effects of various parameters including adsorption time, equilibrium pH, adsorbent dosage and initial adsorbate concentration were investigated. The optimum contact time and pH for the removal of BPA were 60 min and 2, respectively. It was found that the adsorption isotherms best matched the Freundlich model, the adsorption of BPA being multilayer and that of the albedo surface heterogeneous. From the kinetic studies, it was found that the removal of BPA best matched the pseudo-second order kinetic model. An adsorption mechanism based on the albedo surface molecules is proposed and gives a good account of π-π interactions and hydrogen bonding. Orange albedo, with a maximum BPA loading capacity of 82.36 mg g

The presence of organic pollutants in the environment, especially in water, is recognized as a continuing threat to environmental stability. Therefore, the development of new materials for the removal of organic pollutants in water are of fundamental importance. In this paper, a heterojunction SrSnO3/g-C3N4 photocatalytic system was synthesized and its photocatalytical performance for Rhodamine-B (RhB) degradation has been tested. For this purpose, in situ luminescence measurements were carried out for the first time here, for monitoring the photodegradation process in real time under real reaction conditions performance. The degradation profiles of RhB using the SrSnO3/g-C3N4 composite and pure g-C3N4 showed that the degradation of the dye occurs through different mechanisms including four processes: N-de-ethylation, chromophore cleavage, opening-ring and mineralization. The results demonstrate that the SrSnO3/g-C3N4 ratio 1:1 (SSO3) and 1:2 (SSO4) provide high photocatalytic activity under solar light. Best results were observed for composite SSO3, which displayed TOC removal of 97.3 ± 0.03 % after 4 h of solar exposure, while SSO4 and pure g-C3N4 obtained a rate of 72.4 ± 0.03 % and 44.6 ± 0.04 %, respectively. Result of in situ experiments showed that composite SSO3 was 1.7 times more efficient in the RhB degradation than pure g-C3N4. The toxicity of phototreated solution was evaluated by Fish Embryo Test (FET) showing the successful photodegradation of RhB to non-toxic species.