abstract
Empty pinecones are a largely available byproduct of Pinus pinea L. nut production, mostly concentrated in the Mediterranean area; e.g., in Portugal, around 70,000 tons of pinecones are produced annually. One valorization line for residual biomass is its use as biosorbents for the removal of contaminants in effluents and water courses which are an increasing environmental problem. This study explores the biosorbent potential of pinecones to remove zinc ions from aqueous solutions. We analyzed the morphology and chemical composition of pinecones (9.4% extractives, 37.0% lignin, 68.6% holocellulose, 1.4% ash). The effect of pH and adsorbent dose on the adsorption process was studied, as were the sorption kinetics and isotherms. The pinecones showed good potential to remove Zn ions, with 96% removal at pH 7 and a maximum adsorption capacity of 7.92 mg g-1. The process followed the Freundlich isotherm model, indicating a heterogeneous surface and multilayer adsorption, and the pseudo-second-order kinetic model, suggesting chemisorption as the dominant mechanism. The use of pinecones as bio-adsorbent is therefore a green and low-cost alternative for environmental remediation and biomass waste management.
keywords
PINE-CONE SHELL; AQUEOUS-SOLUTIONS; COMPETITIVE ADSORPTION; PB(II) IONS; REMOVAL; BIOSORPTION; ZN(II); COPPER; BARK; L.
subject category
Environmental Sciences & Ecology
authors
Macena, M; Cruz-Lopes, L; Grosche, L; Esteves, B; Santos-Vieira, I; Pereira, H
our authors
Isabel Cristina Maia da Silva Santos Vieira
Junior Researcheracknowledgements
This research was funded by national funds through the FCT-Foundation for Science and Technology, I.P., by a doctoral scholarship with the reference number 2023.03677.BDANA (DOI 10.54499/2023.03677.BDANA); by the CERNAS-IPV Research Centre under the project UIDB/00681, (DOI 10.54499/UIDP/00681/2020); and by the Forest Research Centre (CEF), within the scope of the projects UIDB/00239/2020 (DOI 10.54499/UIDB/00239/2020).