Enhancement of the Adsorption Performance of Multiwalled Carbon Nanotubes via APTES Functionalization for Phenol Removal

Why It Matters

The breakthrough offers a more efficient, potentially cost‑effective alternative to traditional activated carbon for industrial phenol remediation, addressing a critical environmental challenge.

Key Takeaways

• APTES grafting yields 55% phenol adsorption capacity
• Oxidation improves capacity to 17%, untreated negligible
• MWCNT‑APTES outperforms conventional activated carbon
• Functionalization confirmed via FTIR, XRD, TGA analyses
• Promising adsorbent for industrial wastewater treatment

Pulse Analysis

Phenol contamination remains a persistent threat in effluents from pharmaceutical and chemical manufacturing, demanding adsorbents that combine high capacity with rapid kinetics. Conventional activated carbon, while widely used, suffers from limited surface functionality and regeneration challenges, prompting researchers to explore nanomaterials that can be tailored at the molecular level. Multiwalled carbon nanotubes (MWCNTs) possess intrinsic high surface area, yet their pristine form exhibits poor affinity for polar organic molecules, necessitating surface engineering to unlock their full potential.

In the recent study, MWCNTs underwent a two‑step modification: oxidative treatment introduced carboxyl groups, followed by silanization with 3‑aminopropyl triethoxysilane (APTES). The amine‑rich APTES layer creates additional hydrogen‑bonding sites, dramatically increasing phenol uptake to 55.17%—over three times the performance of oxidized MWCNT‑COOH and markedly higher than activated carbon under identical conditions. Spectroscopic (FTIR), diffraction (XRD) and thermogravimetric analyses verified the successful grafting, while adsorption isotherms highlighted the material’s favorable thermodynamics and rapid equilibrium attainment.

The implications for water‑treatment infrastructure are significant. MWCNT‑APTES offers a scalable, high‑efficiency platform that could reduce operational costs by lowering adsorbent dosage and extending regeneration cycles. Integration into existing filtration modules is feasible, given the material’s compatibility with standard column designs. Future work should focus on pilot‑scale evaluations, long‑term durability assessments, and life‑cycle analyses to confirm environmental benefits. As regulatory pressure intensifies on phenol discharge limits, such advanced nanoadsorbents are poised to become pivotal components of next‑generation wastewater treatment solutions.