No abstract

A membranous shaped Ni/Zn layered double hydroxide based nanohybrid was obtained using a low-cost template-free hydrothermal process at optimized growth conditions of 180 °C for 6 h. The synthesized nanohybrid was structurally, texturally and morphologically characterized using different techniques such as X-ray diffraction, FTIR, XPS spectroscopy, BET analysis and FESEM microscopy. The adsorption performance of our product was estimated through the Azorubine dye removal from synthetic wastewater. We therefore studied the synergic effects of Ni/Zn adsorbent dosage, contact time, pH, adsorbate concentration, stirring speed and temperature on the Azorubine adsorption efficiency. In this investigation, we obtained bi-structure based nanoadsorbent with 54% crystallinity order composed of nickel hydrate and zinc carbonate hydroxides in irregular nanoflake-like mesoporous nanohybrid morphology. Interestingly, it was also revealed to have high specific surface area (SSA) of around 110 m2 g−1 with important textural properties of 18 nm and 0.68 cm3 g−1 average pore size and volume, respectively. Moreover, the adsorption results revealed that this novel Ni/Zn layered double hydroxide (Ni/Zn LDH) was an efficient adsorbent for Az molecule and possesses an adsorptive ability exhibiting a short equilibrium time (60 min) and a high Az adsorption capability (223 mg g−1). This fast removal efficiency was attributed to high contact surface area via mesoporous active sites accompanied with the presence of functional groups (OH− and CO32−). In addition, the Langmuir and Freundlich isotherms were studied, and the results fitted better to the Langmuir isotherm.

In this investigation, we report the synthesis of novel homogeneous micro-mesoporous bi-phase nanohybrids based on Ni/Zn hydroxides using a simple and low-cost free-template urea-based hydrothermal process at two different growth temperatures (120 and 180 °C) for 6 h in two cases of precursor ratios (Ni:Zn = 1:1 and Ni:Zn = 1:2). The synthesized products have been characterized with different techniques such as XRD, FT-IR, FESEM, Raman, BET and XPS analysis to identify quantitatively and qualitatively their original physico-chemical properties. The obtained structural results show the formation of bi-hydroxide-based products: α * -Ni(OH) 2 •0.75 H 2 O with Zn 5 (CO 3 ) 2 (OH) 6 (case Ni:Zn = 1:1) or with Zn 4 (CO 3 )(OH) 6 •H 2 O (Ni:Zn = 1:2) which are also proven by FTIR and Raman analyses. However, the obtained 3D micro-meso-nanohybrids with different pore morphology have been demonstrated through the FESEM micrographs depending on the synthesis conditions. Moreover, these porous products have been subjected to textural studies with the BET results showcasing a porous morphology with a reasonable specific surface area (SSA) and pore volume in the range (70-150 m 2 /g) and (0.19-0.85 cm 3 /g), respectively. Also, a clear improvement in the BET SSA (two times the initial value) was obtained with increasing the growth temperature in the two cases (1:1 and 1:2). Consequently, we have successfully synthesized active mesoporous materials with interesting specific surface area and porosity (pore volume and size) which make them attractive materials for electrode applications especially in energy storage and biosensing.