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.

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.

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