Purification Behavior of Zn(II) in Water by Magnesium Hydroxyapatite: Surface Complexation, and Dissolution–Precipitation

Abstract

As an innovative and economical material, hydroxyapatite does little harm to the environment. In this study, a magnesium hydroxyapatite (Mg-HAP) adsorbent was prepared by doping magnesium. Magnesium doping can increase the hydroxyl groups on the surface of Mg-HAP to form more adsorption sites and improve the removal effect of the heavy metal Zn(II) in water. This study was implemented to survey the effect of different sorption elements, including the liquor initial pH, initial concentration, dose of adsorbents, and other factors, on the adsorption effect. The outcomes show that the sorption effect was best at the time that the liquor was weakly acidic (pH = 6); At a pH of 6, the temperature of 25 °C when the optimal dosage of adsorbent is 0.25 g, the maximum adsorption amount is 62.11 mg/g. Through data fitting, the adsorption process can be accurately described as a pseudo-second-order dynamics model and the Langmuir isotherm equation. According to the thermodynamic analysis, the sorption of zinc ions by Mg-HAP belongs to the process of spontaneous endothermic and entropy increase, and the increase of temperature was conducive to adsorption. Material characterization and analysis indicate that surface complexation and dissolution-precipitation was the main mechanism for adsorption of Zn(II).

Investigation into Effect of Natural Shellac on the Bonding Strength of Magnesium Substituted Hydroxyapatite Coatings Developed on Ti6Al4V Substrates

“…Characteristic peaks of O, Mg, P, Cl and Ca can be observed in Figure 4 and its corresponding atomic percentage is also presented. Presence of Mg, Ca and P indicate that Mg has entered into the lattice structure of HA, which corroborates studies previously conducted [39].…”

Assessment of the Water Quality in the Damietta Branch of the Nile River, Egypt

“…The highest concentration of Zn was recorded at the Talkha station, likely due to a decrease in the sorption of Zn with the drop in water levels and the dissolution of clay containing zinc ions, resulting in a high content of Zn in the water. It is also possible that the decay of phytoplankton contributed to this high concentration (Mo et al, 2020). The concentration of Zn in the studied area falls within the permissible limit (5mg/ L) set by the Egyptian Organization for Standardization (1993).…”

The sorption of Tebuconazole and Linuron from an Aqueous Environment with a Modified Sludge-Based Biochar: Effect, Mechanisms, and Its Persistent Free Radicals Study

“…From the temperature perspective, the increased temperature directly results in a corresponding increase in the removal rate and unit adsorption amount. It may be attributed to the increase of surface activity and the effective active center of the adsorbent [69]. erefore, the increase of temperature could promote the adsorption of tebuconazole and linuron in an aqueous solution.…”