# Lignocellulosic Byproducts as Bio-Adsorbents for Lead Removal

## TL;DR

This study shows that lignocellulosic byproducts can effectively remove lead from water, offering a sustainable solution to metal pollution.

## Contribution

The study evaluates the adsorption potential of four lignocellulosic byproducts for lead removal, highlighting their efficiency and mechanisms.

## Key findings

- Lead removal rates of 97–99% were achieved under optimized conditions.
- The pseudo-second-order model best describes the adsorption kinetics, indicating chemisorption as the main mechanism.
- Both Langmuir and Freundlich isotherms fit the data well, showing strong adsorption capacity.

## Abstract

Water pollution by toxic metals, especially by lead ions, is a serious environmental concern due to these metals’ persistence, bioaccumulation, and toxicity. Aiming to reduce metal concentrations to non-toxic levels, this study analyzed the removal of lead from water through adsorption with bio-adsorbents. The adsorbent potential of the following four lignocellulosic byproducts were tested: walnut and chestnut shells, pine wood, and burnt pine wood. Removal rates of 97–99% were achieved at optimized conditions, i.e., at a pH of approximately 7, adsorbent dose of 4 g L−1, and 12 h of reaction. The BET specific surface area was between 1.74 and 4.85 m2 g−1. The pore size of the wood bio-adsorbent was 26.54 nm, and those of the remaining materials were between 5.40 and 7.33 nm. With R2 = 0.998–1.000, the kinetics fit the pseudo-second-order model better, suggesting that chemisorption is the dominant mechanism. Both Langmuir and Freundlich isothermal models fit the data well, with R2 = 0.946–0.999. It can be concluded that all the bio-adsorbents tested have the potential to efficiently remove lead ions from water.