# Processing Cellulose Acetate into Hierarchically Porous Monoliths via Thermally Impacted Nonsolvent-induced Phase Separation with Octanol: Application in Dye Adsorption

## TL;DR

Researchers made porous cellulose acetate structures using a new method with octanol, which can efficiently remove dyes from water.

## Contribution

A novel nonsolvent (n-octanol) is introduced in TIPS/NIPS to fabricate hierarchically porous CA monoliths for dye adsorption.

## Key findings

- The CA monoliths achieved 90% dye removal efficiency within 180 minutes.
- The structures showed a high porosity of 90.68% and a specific surface area of 34.33 m² g⁻¹.
- Methanol and ethanol enabled up to 70% recovery of the adsorbed dye.

## Abstract

This study reports
the fabrication of hierarchically
porous cellulose
acetate (CA) monoliths via thermally impacted nonsolvent-induced phase
separation (TIPS/NIPS), employing n-octanol as a
novel nonsolvent. A ternary phase diagram (TPD) of the CA/DMF/n-octanol system was constructed to define optimal processing
conditions in the metastable region, enabling the formation of continuous
monolithic structures. The resulting CA monoliths exhibited a sponge-like
morphology with interconnected meso- and macropores, a specific surface
area of 34.33 m2 g–1, a high porosity
of 90.68 ± 0.66%, and a low density of 103.12 mg cm–3. Adsorption studies using crystal violet (CV) as a model contaminant
demonstrated efficient dye removal (∼90%) within 180 min, reaching
the highest adsorption capacity of 0.92948 mg g–1, as determined by the Langmuir model. Kinetic modeling indicated
that the adsorption followed a pseudo-second-order mechanism, suggesting
chemisorption, whereas the equilibrium data fit best to the Langmuir
isotherm model, indicating monolayer adsorption. Desorption studies
showed that methanol and ethanol enabled CV recovery with efficiencies
of up to 70%. These results confirm that the combination of TIPS/NIPS
and n-octanol provides a promising, tunable platform
for producing sustainable CA-based monoliths for wastewater treatment
and dye removal.