The Effect of Lithium Ion Leaching from Calcined Li–Al Hydrotalcite on the Rapid Removal of Ni2+/Cu2+ from Contaminated Aqueous Solutions

Abstract

A layered double hydroxide (LDH) calcined-framework adsorbent was investigated for the rapid removal of heavy metal cations from plating wastewater. Li–Al–CO3 LDH was synthesized on an aluminum lathe waste frame surface to prepare the sorbent. The calcination treatment modified the LDH surface properties, such as the hydrophilicity and the surface pH. The change in surface functional groups and the leaching of lithium ions affected the surface properties and the adsorption capacity of the heavy metal cations. A zeta potential analysis confirmed that the 400 °C calcination changed the LDH surface from positively charged (+10 mV) to negatively charged (−17 mV). This negatively charged surface contributed to the sorbent instantly bonding with heavy metal cations in large quantities, as occurs during contact with wastewater. The adsorption isotherms could be fitted using the Freundlich model. The pseudo-second-order model and the rate-controlled liquid-film diffusion model successfully simulated the adsorption kinetics, suggesting that the critical adsorption step was a heterogeneous surface reaction. This study also confirmed that the recovered nickel and/or copper species could be converted into supported metal nanoparticles with a high-temperature hydrogen reduction treatment, which could be reused as catalysts.

Recent Progress on the Adsorption of Heavy Metal Ions Pb(II) and Cu(II) from Wastewater

“…In addition, copper can oxidize the fat of lysosomes, resulting in the rupture of lysosome membranes and the release of a large amount of hydrolase, which would cause liver tissue necrosis. Cu 2+ ions can inhibit cell viability and alter the mRNA expression of cell cycle-related genes and the production of antioxidant oxidation [ 40 ], resulting in kidney damage, gastrointestinal distress [ 41 ], anemia, coma, and eventually death [ 42 ].…”

Hydrotalcites as Versatile Functional Materials for Renewable Feedstock Upgrading to Value-added Chemicals

“…Since they are a prime alternative for homogeneous base catalysts (e.g., hydroxides) with the advantage of eliminating waste liquid streams and ease of separation from reaction media, they can open vast avenues for the synthesis of green chemicals [10][11][12] . Hydrotalcites are also known as inorganic materials with a "memory effect" due to their reversible reconstruction/recrystallization properties stemming from their alterable hydration level [13,14] . Regarding their layered structure, ion-exchange ability and unique characteristics, they have demonstrated a versatile role in energy sectors such as water-gas shift reaction, CO 2 capture/utilization (CCU), gas separation, H 2 production, pollutant elimination and energy storage [3,[15][16][17][18][19][20] , and together with the simplicity of synthesis, the interest in the application of these materials has been increased, recently [21] .…”