Pesticides are widely used in agriculture to increase and protect crop production. A substantial percentage of the active substances applied is retained in the soil or flows into water courses, constituting a very relevant environmental problem. There are several methods for the removal of pesticides from soils and water; however, their efficiency is still a challenge. An alternative to current methods relies on the use of effective adsorbents in removing pesticides which are, simultaneously, capable of releasing pesticides into the soil when needed. This reduces costs related to their application and waste treatments and, thus, overall environmental costs. In this paper, we describe the synthesis and preparation of activated carbon-containing poly(β-cyclodextrin) composites. The composites were characterized by different techniques and their ability to absorb pesticides was assessed by using two active substances: cymoxanil and imidacloprid. Composites with 5 and 10 wt% of activated carbon showed very good stability, high removal efficiencies (>75%) and pesticide sorption capacity up to ca. 50 mg g⁻¹. The effect of additives (NaCl and urea) was also evaluated. The composites were able to release around 30% of the initial sorbed amount of pesticide without losing the capacity to keep the maximum removal efficiency in sorption/desorption cycles.

This study introduces reusable polyacrylic membranes, fabricated from commercially available monomers (1-vinyl-2-pyrrolidone and methylmethacrylate), as a promising approach for pesticide extraction. These membranes effectively remove the commonly used herbicides mecoprop (RE ≈ 99%) and bentazon (RE ≈ 95%) at low concentrations, which pose water contamination risks due to their water-soluble properties and leaf-level sorption. The membranes exhibit excellent manageability and resistance, allowing for safe handling without personal protective equipment. Additionally, the material is environmentally friendly and can be washed and reused for at least 4 cycles without a significant decrease in performance. Characterization techniques, including NMR, TGA, DSC, mechanical testing, N2 adsorption, and FTIR analysis, were used to investigate properties and assess the influence of the polymeric composition. The study focused on examining the lateral charged aminoethyl groups, which play a crucial role in sorbent-sorbate interactions. Sorption kinetics, isotherms, and permeation studies provided insights into the removal mechanism, efficiency, and permeability coefficients, revealing hydrophobic–hydrophobic interactions between the pesticides and the polymer. Molecular dynamics simulations revealed a scorpion-like conformation of the macromolecular chains surrounding the pesticides. These findings support the hydrophobic nature of the extraction mechanism and highlight the significant role of charged aminoethyl groups in facilitating this process.

Metal ions such as cobalt (II) and chromium (III) might be present in the oral cavity, as a consequence of the corrosion of Co-Cr dental alloys. The diffusion of such metal ions into the organism, carried by saliva, can cause health problems as a consequence of their toxicity, enhanced by a cumulative effect in the body. The effect of the chlorhexidine digluconate, which is commonly used in mouthwash formulations, on the transport of these salts is evaluated in this paper by using the Taylor dispersion technique, which will allow an assessment of how the presence of chlorhexidine digluconate (either in aqueous solution or in a commercial formulation) may affect the diffusion of metal ions. The ternary mutual diffusion coefficients of metal ions (Co and Cr) in the presence of chlorhexidine digluconate, in an artificial saliva media, were measured. Significant coupled diffusion of CoCl₂ (and CrCl₃) and chlorhexidine digluconate is observed by analysis of the non-zero values of the cross-diffusion coefficients, D₁₂ and D₂₁. The observed interactions between metal ions and chlorhexidine digluconate suggest that the latter might be considered as an advantageous therapeutic agent, once they contribute to the reduction of the concentration of those ions inside the mouth.