Eco-friendly porous poly(lactic acid)/alkali-treated walnut shell powder composites for the removal of methylene blue

In recent years, polymer-based adsorption materials have been investigated intensively. However, either natural or synthetic polymers exhibit limited absorbing performances. Herein, eco-friendly porous composites based on poly(lactic acid)/alkali-treated walnut shell powder (PLA/AWSP) were fabricated by a facile solution mixing approach. The methylene blue (MB) adsorption behaviors of composites containing different AWSP contents were discussed. Furthermore, the effects of contact time, initial MB concentration, solution pH and temperature were studied to explore the adsorption performance of the adsorbents under different conditions. Results indicated that the adsorption process was accordance with pseudo-second-order kinetics and fitted well with Langmuir isotherm model. PLA/AWSP exhibited stable adsorption capacity and the removal efficiency on MB. The obtained porous biosorbent demonstrates excellent adsorption properties, which offers a wide range of applications in the field of separation and adsorption.