Lignin/Poly(vinyl alcohol) Hydrogel for Detecting and Effectively Removing Microplastics

Area of Science:

• Materials Science
• Environmental Science
• Polymer Chemistry

Background:

• Microplastic pollution is a growing environmental concern, necessitating effective removal strategies.
• Lignin, a bio-based polymer, offers potential as a precursor for functional materials.
• Developing sustainable adsorbents is crucial for mitigating environmental contamination.

Purpose of the Study:

• To synthesize and characterize a novel biobased hydrogel from aminated lignin and poly(vinyl alcohol).
• To evaluate the hydrogel's adsorption performance for various microplastic types, including polystyrene microplastics (PSMP).
• To assess the hydrogel's efficiency in different water matrices and its reusability for sustainable applications.

Main Methods:

• Lignin extraction from bamboo powder followed by phenolization and ammoniation.
• Hydrogel synthesis via aminated lignin and poly(vinyl alcohol) crosslinking.
• Characterization using SEM, FTIR, and N2 adsorption-desorption; adsorption studies for microplastics.

Main Results:

• The synthesized hydrogel demonstrated a high maximum adsorption capacity of 288.6 mg/g for PSMP, following pseudo-second-order kinetics and Langmuir isotherm.
• The hydrogel maintained 87.64% efficiency after five regeneration cycles.
• Effective adsorption was observed for multiple microplastic types (PEMP, PPMP, PVCMP, PAMP) in various water matrices, with rates exceeding 92% for PSMP and 96% for PAMP.

Conclusions:

• The aminated lignin-based hydrogel is a highly efficient and reusable adsorbent for microplastic removal.
• This biobased material presents a sustainable and eco-friendly strategy for tackling microplastic pollution in diverse environmental settings.
• The study provides essential data for developing advanced adsorbents targeting small-sized microplastics in water treatment applications.