الفهرس 
Chapter 1 : IntroductionOnly 14 pages are availabe for public view
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Abstract
from what has been discussed, we can conclude that:
The adsorption efficiency of Zn-Co-Fe/LDH was influenced by pH, adsorbent dose, concentration, and time. The removal efficiency of Zn-Co-Fe/LDH at pH 7 reached 86.2% for an adsorbent dose of 0.1g at room temperature.
Chemical and thermal stability of Zn-Co-Fe/LDH was confirmed by XRD spectra.
FTIR spectra were analyzed, and it was found that the existence of the dipole-dipole hydrogen bonding, coordination interaction, and electrostatic attraction mechanism was based on the interaction between the cationic MB and negatively charged sites on the surface of Zn-Co-Fe/LDH (pH > 6.7).
The morphology of LDHs was confirmed by SEM images, indicating the presence of pores, and revealing plate-like particles layered on top of one another. TEM images were used to confirm the presence of loading MB on the LDH surface.
The equilibrium adsorption was investigated by the two isothermal models. The fitting parameters revealed that both the Freundlich and Langmuir models can successfully fit the Zn-Co-Fe/LDH isotherm processes, with the qmax determined to be 58.26 mg/g.
The adsorption kinetics of Zn-Co-Fe/LDH was investigated by a pseudo-second-order model, confirming the adsorption is chemisorption.
The waste of Zn-Co-Fe LDH/MB was reused in another adsorption test, and the removal efficiency of Zn-Co-Fe/LDH decreased to 60.3% after five cycles.
According to the thermodynamic characteristics, MB adsorption on Zn-Co-Fe/LDH was non-spontaneous and exothermic.
The waste of Zn-Co-Fe LDH/MB from different calcination temperatures (200, 400, and 600 oC) was repurposed as a new and low-cost catalyst for direct methanol fuel cells.
LDH-400 oC had the highest pore width (6.38 nm), which plays the most important role in its electrocatalytic activity by enabling the easier entrance of reactive species to the active sites.
In 3M methanol, the LDH-400 oC achieved a current density of 41.11 mA/cm2 at 50 mV/s. The obtained plots from the CV tests showed the redox behaviour of methanol with better stability for the LDH-400 oC.
The removal efficiency of the LDH/PVDF membrane at pH 7 reached 95.5% for an adsorbent dose of 0.1g at room temperature.
The waste of LDH/PVDF membrane was reused in another adsorption test, and the removal efficiency decreased to 81.4% after seven cycles.