Fabrication of superhydrophobic sorbent material via in-situ coating of melamine sponge with halloysite nanotube and fluoroalkylsilane using supercritical CO2 coating system for efficient oily water treatment

DUMAN O., CENGİZ U., ÖZCAN DİKER C., Güreşir S. M., TUNÇ S., Cengiz C.

Separation and Purification Technology, cilt.360, 2025 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 360
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1016/j.seppur.2024.131069
  • Dergi Adı: Separation and Purification Technology
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Biotechnology Research Abstracts, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC, Metadex, Pollution Abstracts, Civil Engineering Abstracts
  • Anahtar Kelimeler: Activated halloysite nanotube, Fluoroalkylsilane, scCO2 coating system, Selective oil removal, Superhydrophobic sponge-based sorbent
  • Çanakkale Onsekiz Mart Üniversitesi Adresli: Evet

Özet

This study presents the preparation of a novel sorbent material with high performance and special wettability for oily water treatment, utilizing halloysite nanotube (HNT) and perfluorooctyl triethoxysilane (PFOTES). Fluoroalkyl silanes, such as PFOTES, offer significant advantages over other monomers and alkoxysilanes due to their superior water-repellent properties and high solubility in CO2 atmosphere, enabling homogeneous polymerization and coating. The modification of PFOTES with HNT was successfully achieved in the supercritical CO2 (scCO2) environment at 35 °C and 125 bar using a sol–gel technique. Subsequently, HNT-modified PFOTES nanoparticles were coated onto melamine sponge (MS) via a drainage technique, marking the first application of this method to create a superhydrophobic (WCA: 165.2°) and superoleophilic (OCA: 0°) sorbent material (MS-PFOTES). The MS-PFOTES sorbent material, produced via a one-step, two-pot coating method, demonstrated exceptional sorption capacities ranging from 39.1 to 117.5 g/g for oily pollutants / organic solvents. Additionally, MS-PFOTES achieved an outstanding separation efficiency of 99.99 % for diesel-water mixtures in continuous separation processes. The fabricated material also exhibited remarkable thermal stability, chemical resistance, and robustness. Experimental findings obtained in this study highlight the significant potential of this innovative coating technique for the direct preparation of sorbent material with special wettability for oily water treatment.