The use of low-cost biowaste adsorbents for the removal of toxic metal ions from aqueous solutions offers significant environmental benefits. This research evaluated the adsorption and recovery of Cd²⁺ and Pb²⁺ ions in batch and column modes with luffa peels and chamomile flowers. The biosorbents were treated with 0.4 M nitric acid or with 0.4 M NaOH base. An FTIR analysis of the sorbents indicated that surface OH, C=O, CO and COO groups played a role in the adsorption process. L-type isotherms were obtained for Pb²⁺, fitting both the Langmuir and Freundlich models, with maximum adsorption capacities of 34.0 mg/g for luffa peels and 49.5 mg/g for chamomile flowers. Adsorption isotherms for Cd²⁺ ion fit better with the Freundlich model with smaller adsorption capacity than Pb²⁺. Base-treated sorbents have higher adsorption capacity. The adsorption kinetic for both ions are fast and followed a pseudo-second order chemosorption model. Fixed-bed column dynamic adsorption with luffa peels obtained a Thomas dynamic adsorption capacity of 32.9 mg/g for Pb²⁺ and 25.8 mg/g for Cd²⁺. The recovery efficiency was 87 to 90% over three adsorption–regeneration cycles.

The adsorption of As(V) and As(III) (0.01–1 mM) on a calcined oxidic lithologic material substrate with pH-dependent surface variable charges, chemically modifiable, was investigated. The substrate was prepared via thermal treatment using a natural lithologic material rich in amphoteric oxides of Fe, Al, Mn and Ti. The calcined substrate was treated with acid media (HCl 0.1) to homogenize the positive charge density on the oxide surface via oxide protonation so that anion adsorption would be favored. A batch experiment was performed on the acid-treated substrate (activated) and non-activated substrate. L-type isotherms were obtained, which fit the Freundlich model. Isotherm constants showed that there was a greater affinity between the activated substrate and As(V) (K = 10.58) compared to As(III) (K = 5.45). The adsorption capacity of the activated substrate was two times greater than that of the non-activated substrate, As(V) (K_act = 10.58 and K_noact = 5.45) vs. As(III) (K_act = 5.45 y K_noact = 2.44), which was due to the greater positive charge density on the activated surface, created by the protonation of the surface oxides. Protons were liberated during the adsorption reaction (As(V): 2.17 × 10⁻³ and As(III): 0.96 × 10⁻³ mmol/mL). The forms H₂AsO₄⁻ and H₃AsO₃ deprotonated when adsorbed by the surface groups $\mathrm{M}-\mathrm{O}{\mathrm{H}}_2^{+}$ (M: Fe, Al). Kinetic data showed a second-order process for As(V) adsorption and a first-order process for As(III) adsorption. The adsorption rate on the activated substrate was two times greater compared with the non-activated substrate: As(V) (k_act = 3.78 × 10⁻⁵ L/mg·min and k_noact = 2.16 × 10⁻⁵ L/mg·min) vs. As(III) (k_act = 0.055 h⁻¹ and k_noact = 0.027 h⁻¹). The tested substrate is potentially useful as a low-cost natural material for arsenic removal from contaminated water.

The luminescence characteristics of six osmium carbonyl complexes with phenanthroline (phen) or bipyridine (bpy) and pyridine (py), 4-phenylpyridine (4-phpy), or triphenylphosphine (PPh₃) complexes in the presence of polyanion heparin were studied in both ethanol and aqueous solutions. The influence of heparin on the luminescence of the complexes is heavily dependent on the type of ligands in the complexes and the solvent used. In the ethanol solutions, the heparin solution enhanced the luminescence of the five osmium complexes, with the strongest enhancement to the 4-phenylpyridine complexes; linear curves were obtained in the luminescence enhancement ratio (F/F0) versus the heparin concentration range of 1–40 μg/mL. In aqueous solutions, heparin quenching of the complexes was more significant; a linear quenching curve was obtained with [Os(phen)₂CO(PPh₃)](PF₆)₂in the lower concentration range of 1–12 μg/mL. The interaction of these complexes with heparin in the solutions is discussed. The complexes are shown to be successful in the fast and sensitive detection of heparin in commercial injectable samples.

This work presents the studies of the interactions of two newly synthesized anticancer drug candidates (AR2 and AR3, analogues of WZ4002) with anilinopyrimidine scaffolding core moiety with bovine serum albumin (BSA) and human serum albumin (HSA) using UV-Vis absorption, fluorescence spectroscopy and molecular docking techniques.