C14h14n3nao3s

Benzene (C₆H₆, >99.5% purity, Kanto Chemical Co., Inc., Japan) and potassium permanganate (KMnO₄, >99.3% purity, Wako Pure Chemical Industries Ltd., Japan) were selected as the carbon and manganese oxide precursors, respectively. DCH18C6 (C₂₀H₃₆O₆, >98.0%, Tokyo Chemical Industry Co., Ltd., Japan) was used as the main chemical agent for preparing purple benzene. Manganese(IV) oxide powder (85% purity, Kanto Chemical Co., Inc., Japan) was used as a commercial MnO₂ sample for comparing the dye removal performance with the as-prepared adsorbents. Ethanol (C₂H₅OH, >99.5%), hydrochloric acid (HCl, 35–37%), and a sodium hydroxide solution (NaOH, 48–50%) were purchased from Kanto Chemical Co., Inc., Japan. MB (C₁₆H₁₈ClN₃S·3H₂O, 98.5% purity, Kishida Chemical Co., Ltd., Japan), Rh B (C₂₈H₃₁ClN₂O₃, Guaranteed reagent, Wako Pure Chemical Industries Ltd., Japan) and MO (C₁₄H₁₄N₃NaO₃S, ACS reagent, dye content 85%, Sigma-Aldrich, Japan) were selected as typical cationic and anionic organic dyes. Distilled water was obtained from an Aquarius water distillation apparatus (RFD250NB, Advantec, Japan) with a resistivity of 18.2 MΩ cm at 25 °C. All chemicals were used without further purification.

Fe(NO₃)₃·9H₂O 96%, Co(NO₃)₂·6H₂O, chitosan, and glacial acetic acid (analytical grade, Sigma-Aldrich Chemie GmbH, Steinheim, Germany) were used in the synthesis of magnetic materials. NaOH pellets, HCl 35% suprapure and NH₄OH 25% (analytical grade) were purchased from Merck KGaA Darmstadt, Germany. Congo Red (CR) 99% (C₃₂H₂₂N₆Na₂O₆S₂) and Methyl Orange (MO) (ACS reagent, dye content 85 %, C₁₄H₁₄N₃NaO₃S, Sigma-Aldrich Chemie GmbH, Steinheim, Germany) and ultrapure water were used for preparing the dye solutions. Ethyl alcohol (95%) and acetone (99%) (Sigma-Aldrich Chemie GmbH, Steinheim, Germany) were used as desorbing agents, while ammonium acetate 99% and acetonitrile 99% (Merck KGaA Darmstadt, Germany) as mobile phase for chromatographic separation and detection were used.

The cobalt ferrite samples were prepared by the use of Fe(NO₃)₃·9H₂O 99%, Co(NO₃)₂·6H₂O and sodium bis-2-ethyl-hexyl sulfosuccinate (analytical grade, Sigma Aldrich, St. Louis, MO, USA). NH₄OH 25% and HCl 35% suprapure (analytical grade, Merck KGaA Germany, Darmstadt, Germany) were used to adjust the solution’s pH. The dye solutions of desired concentrations were obtained from Congo Red (CR) 99% (C₃₂H₂₂N₆Na₂O₆S₂) and Methyl Orange (MO) (ACS reagent, Dye content 85%, C₁₄H₁₄N₃NaO₃S, Sigma Aldrich). Ethyl alcohol (95%) (Sigma Aldrich, St. Louis, MO, USA) was applied as a desorbing agent. Ammonium acetate 99% and acetonitrile 99% (Merck KGaA Germany, Darmstadt, Germany) were utilized as a mobile phase for the dye’s chromatographic separation and detection.