Industrial hemp (Cannabis sativa L.) was investigated as a sustainable biosorbent for removing Congo Red (CR) and Remazol Brilliant Blue R (RBBR) from wastewater. The unmodified hemp biosorbent exhibited moderate but practically relevant sorption capacities (4.47 mg/g for CR; 2.44 mg/g for RBBR), outperforming several agricultural waste materials. Kinetic studies revealed rapid uptake, with CR following pseudo-first-order kinetics (t₁/₂ < 15 min) and RBBR fitting the Elovich model, indicating heterogeneous surface interactions. Equilibrium data showed CR adsorption was best described by the Temkin isotherm (R² = 0.983), while RBBR followed the Langmuir model (R² = 0.998), reflecting their distinct binding mechanisms. Thermodynamic analysis confirmed spontaneous (ΔG° < 0), exothermic (ΔH° ≈ −2 kJ/mol), and entropy-driven processes for both dyes. Molecular docking elucidated the structural basis for performance differences: CR’s stronger binding (−7.5 kcal/mol) involved weak noncovalent interaction arising from partial overlap between the π-electron cloud of an aromatic ring and σ-bonds C-C or C-H (π-σ stacking) and hydrogen bonds with cellulose, whereas RBBR’s weaker affinity (−5.4 kcal/mol) relied on weak intermolecular interaction between a hydrogen atom (from a C-H bond) and the π-electron system of an aromatic ring (C-H∙∙∙π interactions). This work establishes industrial hemp as an eco-friendly alternative for dye removal, combining renewable sourcing with multi-mechanism adsorption capabilities suitable for small-scale water treatment applications.

Herein, we report on the synthesis and pharmacological evaluation of ten novel fluorinated cinnamylpiperazines as potential monoamine oxidase B (MAO-B) ligands. The designed derivatives consist of either cinnamyl or 2-fluorocinnamyl moieties connected to 2-fluoropyridylpiperazines. The three-step synthesis starting from commercially available piperazine afforded the final products in overall yields between 9% and 29%. An in vitro competitive binding assay using l-[³H]Deprenyl as radioligand was developed and the MAO-B binding affinities of the synthesized derivatives were assessed. Docking studies revealed that the compounds 8–17 were stabilized in both MAO-B entrance and substrate cavities, thus resembling the binding pose of l-Deprenyl. Although our results revealed that the novel fluorinated cinnamylpiperazines 8–17 do not possess sufficient MAO-B binding affinity to be eligible as positron emission tomography (PET) agents, the herein developed binding assay and the insights gained within our docking studies will certainly pave the way for further development of MAO-B ligands.