Anhydrous ethanol

In the present work, a commercial micronized poly(vinyl chloride) resin was used with an average molar mass of about 93.4 × 10³ g·mol⁻¹. The resin was supplied by Polyvin, a Brazilian company specialized in the production of PVC pipes and fittings.
For the chemical modifications of the PVC-micronized resin, the following reagents were used: anhydrous tetrahydrofuran-THF (Sigma-Aldich, São Paulo, Brazil) (99.99%), poly(ethylene glycol)-PEG (Vetec, Rio de Janeiro, Brazil) molar mass 400 g·mol⁻¹, anhydrous sulfuric acid (Vetec) (95–99%), potassium hydroxide-KOH (Modern Chemistry, São Paulo, Brazil), pellets (98%), and anhydrous ethanol (Vetec) (96–98%).
For adsorption experiments, deionized water was used throughout all experiments to prepare the solutions. The dye acetate of 3,7-diamino-5-phenothiazine (dye used in microscopy), Lauth’s Violet (VL) or thiazine (C₁₄H₁₃N₃O₂S, CI-52,000, 287.34 g·mol⁻¹, λ_max 597–601 nm, pH ~ 6.8 see Figure 12) was obtained from Lobal Chemie with a dye content of 85% and was used without further purification. The amino groups in the dye structure give the molecule basic ionization characteristics and the thioether is responsible to the positive charge. The stock solution was precisely prepared by dissolving the dye in distilled water to a concentration of 600 mg·dm⁻³. The working solutions were obtained from dilutions of stock solution of the dye.