A range of Cu-LDHs has been synthesized by co-precipitation using metal nitrate precursors and sodium carbonate under varying molar ratios Cu/Al (Cu 0.05 -Al 0.15 , Cu 0.10 -Al 0.10 , Cu 0.14 -Al 0.06 , and Cu 0.15 -Al 0.05 ). The uncalcined and calcined Cu-LDHs were characterized by powder X-ray diffraction and N 2 adsorption-desorption. The uncalcined solids showed clear hydrotalcite-like crystalline phases having a particle measurement between 5 and 16 nm. The best structure is attributed to the sample Cu 0.05 -Al 0.15 -LDHs. The particular surface areas are ranging between 40 and 92 m 2 /g, while the calcined samples showed the formation of Cu and Mg oxides. The antibacterial activity of Cu-LDHs with various molar ratios Cu/Al and their calcined phases were estimated towards multiple types of bacteria (Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, and Bacillus Subtilis). The Cu 0.10 -Al 0.10 -LDHs sample shows high activity against all types of bacteria either for calcined or uncalcined materials. The obtained results of the application of Cu-LDHs antibacterial inhibitors seem to be quite promising material in the antibacterial fields.

The extraction of Zinc (II) in acetate medium with di (2-ethylhexyl) phosphoric acid (D2EHPA) in chloroform diluent was investigated under different experimental conditions, in order to have a better understanding of the extraction mechanism. The extraction yield was found to depend on the concentrations of Zinc (II) and D2EHPA, and the equilibrium pH. The effects of acetic acid and the salting-out agent were also studied.The nature of the extracted species was investigated by the slope analysis method. Graphs of log D vs. log [D2EHPA] and log D vs. pH were plotted for Zn (II), and the species extracted into the organic phase was found to have the composition (ZnCH 3 COO)R.HR.The best performance was reached (80%) with zinc concentrations lower than 5 mM in a neutral medium. The extraction yield of metals decreased as the acetic acid concentration increased with any given extractant concentration. The addition of sodium acetate to the aqueous phase strongly increased the zinc extraction yield (99.5%).A synergistic effect was observed by the addition of tributhylphosphate (TBP) with the organic phase.

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Kinetic study was applied for sodium bentonite (Na-B) and hexadecylpyridinium bentonite (HDP-B) under different amounts, namely 50% (50HDP-B), 100% (100HDP-B), and 200% (200HDP-B) with respect to cation exchange capacity (CEC). Pseudo first-order and pseudo second-order kinetic models were performed to optimize the sorption of Congo red (CR) dye from aqueous solution. The experimental data fit the pseudo second order kinetic model well. The sorption capacity (qe) of CR dye by the organo-bentonites at equilibrium was 36.0 mg g−1 (72.1%) for 50HDP-B, 48.05 mg g−1 (96.1%) for 100HDP-B, and 49.2 mg g−1 (98.4%) for 200HDP-B. These results were considerably higher than that found by Na-B. Response surface methodology with three-variable, three-level Box–Behnken design was applied for 100HDP-B to describe the removal of CR dye. The effects of three variables, namely temperature, adsorbent dosage, and initial dye concentration, were studied. Predicted values of adsorption efficiency were found to be in good agreement with the obtained experimental values (R2 = 0.97). A second-order polynomial model successfully described the effects of independent variables on the CR dye removal. At the optimized condition, the toxic azo dye could be quantitatively removed from aqueous solution. The results of the present study suggest that the organo-bentonite can be used as an efficient sorbent for dye removal from aqueous solution.

The solvent extraction of cadmium(II) from nitrate medium was studied. The using extractants were quaternary ammonium-based room temperature ionic liquid Cd SCN − species with the addition of KSCN. More the hydrophobic character of the extractant is high, more the extraction is better. The metal ion was stripped out satisfactorily using nitric acid as stripping agent, in one step.