Abstract Valorization of adsorbent spent is a modern trend to maximize the utilization of absorption waste. Analytical methods, inclusive Fourier Transform Infra Red (FTIR) spectroscopy, Scanning Electron Microscope (SEM), and X-Ray Diffraction (XRD), were applied to evaluate the adsorbent spent (Zn-Co-Fe/LDH @ heavy metal). We examined the mechanistic toxicological effects of heavy metals within an animal model (rats) via probit analysis to evaluate the safety and acute toxicity of the spent adsorbent. The acute toxicity was evaluated and documented for 24 h, and it persisted for 14 days. A diverse multitude of toxic impacts on a different of body organs and tissues is the consequence of the bioaccumulation of these heavy metals. The rodents were weighed daily, and a variety of observations, like mortality, injury, behavior, and any indications of disease, were conducted. The safety and toxicological analyses were conducted using Probit analysis. The acute toxicity evaluation revealed varying safety profiles for the spent adsorbents. Zn-Co-Fe/LDH-As exhibited the lowest level of toxicity with an LD 50 of 370 mg/kg and a calculated safe dose of 18.5 mg/kg. In contrast, the highest toxicity was observed for Zn-Co-Fe/LDH-Pb (LD 50 = 103.7 mg/kg; safe dose = 5.2 mg/kg), followed by Zn-Co-Fe/LDH-Hg (LD 50 = 204 mg/kg; safe dose = 10.2 mg/kg). These results quantify the biological risk associated with metal-laden adsorbents and establish the safety benchmarks required for their sustainable valorization. Evaluations of biochemical parameters and hematological analysis were conducted at the conclusion of each investigation. Comparative to the controls, gross findings were obtained from the histopathological examination of the animals’ vital organs, which included the heart, lung, kidney, liver, and stomach. Our safety and toxicological data demonstrated the safety of layered double hydroxide (LDH) efficacy in adsorption, as well as a lower level of toxicity for LDH/As after adsorption. The iron content within the Zn-Co-Fe/LDH framework remained structurally integrated; however, the observed hematological alterations suggest a potential interference with iron metabolism or heme synthesis following exposure to heavy-metal laden adsorbents.
Aita et al. (Mon,) studied this question.