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.

Aims: Investigate the changes occurring in the composition of Garcinia kola nut shell after an activation process, especially the characteristics of the chemically activated carbons (ACs) obtained. Study Design: Determine of the physicochemical properties of the prepared ACs using optimized experimental data. Place and Duration of Study: Research Unit of Noxious Chemistry and Environmental Engineering, Department of Chemistry, Faculty of Science, University of Dschang, between February 2016 and March 2018. Methodology: Garcinia kola nut shell (bitter kola nut shell) were used to prepare ACs by chemical activation using H₃PO₄, KOH and ZnCl₂ using the carbonization temperatures 400, 450 and 500°C and the different impregnation ratios 1/1 and 2/1. The effects of the composition of the components on the iodine number and iodine methylene blue number of the ACs were investigated. The best ACs were selected after optimization of the experimental data obtained in the laboratory. Results: Increase in carbonization temperature from 400°C to 500°C led to a decrease in the iodine number and an increase of in burn-off. For the production of ACs, the optimum temperature was found to be 400°C for 1 hour heating, with impregnation ratio of 1/1 by KOH, ZnCl₂ ACs and 2/1 for the H₃PO₄ AC. Thermo-gravimetric analysis of the raw material was carried out to confirm the thermal stability of the ACs obtained at the optimum temperature of 400°C. The functional surfaces of the ACs and raw materials were studied by Bohem titration, pH, pzc, and FT-IR techniques. SEM analysis illustrates an irregular and heterogeneous surface morphology with a developed and fragmented porous structure of various sizes. Powder X-ray diffraction analysis showed that the raw material and ACs prepared are essentially amorphous. Conclusion: Chemical activation is one of the appropriate methods that can be used to obtain new ACs. The maximum iodine number of the ACs was obtained at carbonization temperature of 400°C for a period of 1 hr, with impregnation ratios 2/1 and 1/1.

An amperometric sensor was developed by depositing a film coating of hydroxyapatite (HA)/L-lysine (Lys) composite material on a glassy carbon electrode (GCE). It was applied for the detection of Nile blue A (NBA). Hydroxyapatite was obtained from snail shells and its structural properties before and after its combination with Lys were characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) surface area analyses. The coupling of Lys to HA was attributed to favorable interaction between negatively charged -COO⁻ groups of Lys and divalent ions Ca²⁺ of HA. Electrochemical investigations pointed out the improvement in sensitivity of the GCE/Lys/HA sensor towards the detection of NBA in solution. The dependence of the peak current and potential on the pH, scan rate, and NBA concentration was also investigated. Under optimal conditions, the GCE/Lys/HA sensor showed a good reproducibility, selectivity, and a NBA low detection limit of 5.07 × 10⁻⁸ mol L⁻¹. The developed HA/Lys-modified electrode was successfully applied for the detection of NBA in various water samples.

A new diazo derivative of a pyrrolidine-2,5-dione (8) fused at position-3,4 to a dibenzobarrelene backbone has been prepared by coupling the previously reportedN-arylsuccinimid (5) precursor with aryldiazonium ion of aniline. The initial step of the reaction involved the preparation of the intermediate 9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic anhydride (3) through [4 + 2]-cycloaddition between anthracene and maleic anhydride in refluxing xylene which was then condensed with para-aminophenol to give compound5. Compounds5and8were characterized by their physical, elemental, and spectroscopic data. 2D-NMR (COSY, HSQC, and HMBC) techniques were used to confirm the structure of compound5. Compounds5(MIC = 32–128 μg/mL) and8(MIC = 16–256 μg/mL) along with the precursor3(MIC = 64–128 μg/mL) displayed moderate to low antimicrobial activities against selected bacterial and fungal species when compared with those of nystatin (MIC = 0.50–2 μg/mL) and ciprofloxacin (MIC = 0.50–16 μg/mL) used as reference drugs.Graphical Abstract

In situcharacterisation techniques granted unprecedented experimental access to the formation dynamics of carbonate-intercalated Mg²⁺/Al³⁺LDHs.

A talc-like magnesium phyllosilicate functionalized with amine groups (TalcNH₂), useful as sensor material in voltammetry stripping analysis, was synthesized by a sol–gel-based processing method. The characterizations of the resulting synthetic organoclay by scanning electron microscopy (SEM), X-ray diffraction, N₂ sorption isotherms (BET method), Fourier transform infrared spectroscopy (FTIR), CHN elemental analysis and UV–Vis diffuse reflectance spectroscopy (UV–Vis-DRS) demonstrated the effectiveness of the process used for grafting of amine functionality in the interlamellar clay. The results indicate the presence of organic moieties covalently bonded to the inorganic lattice of talc-like magnesium phyllosilicate silicon sheet, with interlayer distances of 1568.4 pm. In an effort to use a talc-like material as an electrode material without the addition of a dispersing agent and/or molecular glue, the TalcNH₂ material was successfully dispersed in distilled water in contrast to natural talc. Then, it was used to modify a glassy carbon electrode (GCE) by drop coating. The characterization of the resulting modified electrode by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) revealed its charge selectivity ability. In addition, EIS results showed low charge transfer resistance (0.32 Ω) during the electro-oxidation of [Fe(CN)₆]³⁻. Kinetics studies were also performed by EIS, which revealed that the standard heterogeneous electron transfer rate constant was (0.019 ± 0.001) cm.s⁻¹, indicating a fast direct electron transfer rate of [Fe(CN)₆]³⁻ to the electrode. Using anodic adsorptive stripping differential pulse voltammetry (DPV), fast and highly sensitive determination of Pb(II) ions was achieved. The peak current of Pb²⁺ ions on TalcNH₂/GCE was about three-fold more important than that obtained on bare GCE. The calculated detection and quantification limits were respectively 7.45 × 10⁻⁸ M (S/N = 3) and 24.84 × 10⁻⁸ M (S/N 10), for the determination of Pb²⁺ under optimized conditions. The method was successfully used to tap water with satisfactory results. The results highlight the efficient chelation of Pb²⁺ ions by the grafted NH₂ groups and the potential of talc-like amino-functionalized magnesium phyllosilicate for application in electrochemical sensors.