abstract
Lead contamination in water is a serious environmental concern due to its ecotoxic effects. Adsorption is one possible method for treating lead-contaminated water. In this study, the functionalization of alkali-activated blast furnace slag, which is a comparatively new research area, was explored using lignin, and its potential in adsorbing lead from water was investigated. The lignin integration was confirmed by total organic carbon analysis, thermogravimetry, and Fourier-transform infrared spectroscopy. The composite material exhibited 14 units higher lead removal efficiency in comparison to alkali-activated slag without lignin. The effects of contact time (0-6 h), adsorbent dose (0.25-1.5 g/L), initial concentration (50-400 mg/L), pH (3-5), and temperature (20-30 degrees C) on lead adsorption by the composite were investigated. The optimum conditions were contact time 2 h, pH 5, adsorbent dose 1.5 g/L, initial concentration 100 mg/L, and temperature 30 degrees C. The adsorption equilibrium was reached after 2 h. X-ray photoelectron spectroscopy analysis showed enhanced lead adsorption by the composite compared to alkali-activated blast furnace slag without lignin. The adsorption kinetics could be described by the pseudo-second order model and adsorption equilibrium by the Freundlich isotherm. The composite exhibited the highest adsorption amount of approximately 139 mg/g. Thermodynamic parameters, such as changes in enthalpy, entropy, and Gibbs energy, were also evaluated, indicating that the reaction is spontaneous and endothermic.
keywords
POROUS FLY-ASH; METAL-IONS; LEAD II; REMOVAL; GEOPOLYMER; METAKAOLIN; ADSORBENT; GREEN; FTIR
subject category
Science & Technology - Other Topics; Engineering; Environmental Sciences & Ecology
authors
Bhuyan, MAH; Carvalheiras, J; Novais, RM; Luukkonen, T
our authors
João António de Sousa Carvalheiras
PhD Student
Rui Miguel Novais
Assistant ProfessorProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
This study was supported by the University of Oulu and the Center for Material Analysis at the University of Oulu (access to analytical instruments) and KAUTE Foundation (grant No. 20230698). This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 (DOI 10.54499/UIDB/50011/2020), UIDP/50011/2020 (DOI 10.54499/UIDP/50011/2020) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020), financed by national funds through the FCT/MCTES (PIDDAC). Joao Carvalheiras (SFRH/BD/144562/2019) wishes to thank Fundacao para a Ciencia e Tecnologia (FCT) for supporting his work.