TY - JOUR
T1 - Hybrid biosorbents from exopolymeric substances immobilized in Ca-alginate and their biosorption mechanisms in single and multi-metal systems
AU - Cheah, Caleb
AU - Cheow, Yuen Lin
AU - Ting, Adeline Su Yien
N1 - Funding Information:
The authors are grateful to the Malaysian Ministry of Higher Education (MOHE) for the funding under the FRGS grant scheme (FRGS/1/2018/STG03/MUSM/02/1). The authors also thank Monash University Malaysia for providing the resources and facilities to conduct the research.
Publisher Copyright:
© 2023 Taylor & Francis Group, LLC.
PY - 2023
Y1 - 2023
N2 - This study developed a hybrid biosorbent consisting of exopolymeric substances (EPS) from Bacillus cereus immobilized in the gelling agent Ca-alginate. Metal removal tests revealed that the hybrid EPS beads showed significantly higher metal removal compared to plain alginate beads. This higher removal efficacy in hybrid biosorbents was attributed to the increased number of functional groups detected via FTIR analysis. Hybrid EPS beads bind metals via the formation of strong covalent bonds (chemisorption), rather than through weak van der Waals forces (physisorption), complying with the pseudo-second order model. This was consistent in both single and multi-metal systems. For adsorption isotherm, metal removal (pH 5, 25ºC, 120 rpm) by hybrid biosorbents in single metal systems fits the Langmuir isotherm (monolayer adsorption). In multi-metal systems, however, the removal of Zn and Cd demonstrated a better fit to the Freundlich isotherm (multilayer adsorption) compared to the typical Langmuir isotherm (for Cu, Pb and Cr). The isotherm models indicated that the maximum biosorption capacity for Cu, Pb, Zn, Cd and Cr was at 34.97, 156.24, 19.19, 11.66 and 38.61 mg g−1, respectively. The hybrid EPS beads are superior for the biosorption of Cu, Pb and Cr compared to existing biosorbents.
AB - This study developed a hybrid biosorbent consisting of exopolymeric substances (EPS) from Bacillus cereus immobilized in the gelling agent Ca-alginate. Metal removal tests revealed that the hybrid EPS beads showed significantly higher metal removal compared to plain alginate beads. This higher removal efficacy in hybrid biosorbents was attributed to the increased number of functional groups detected via FTIR analysis. Hybrid EPS beads bind metals via the formation of strong covalent bonds (chemisorption), rather than through weak van der Waals forces (physisorption), complying with the pseudo-second order model. This was consistent in both single and multi-metal systems. For adsorption isotherm, metal removal (pH 5, 25ºC, 120 rpm) by hybrid biosorbents in single metal systems fits the Langmuir isotherm (monolayer adsorption). In multi-metal systems, however, the removal of Zn and Cd demonstrated a better fit to the Freundlich isotherm (multilayer adsorption) compared to the typical Langmuir isotherm (for Cu, Pb and Cr). The isotherm models indicated that the maximum biosorption capacity for Cu, Pb, Zn, Cd and Cr was at 34.97, 156.24, 19.19, 11.66 and 38.61 mg g−1, respectively. The hybrid EPS beads are superior for the biosorption of Cu, Pb and Cr compared to existing biosorbents.
KW - Alginate
KW - exopolysaccharides
KW - metal removal
UR - http://www.scopus.com/inward/record.url?scp=85160922625&partnerID=8YFLogxK
U2 - 10.1080/01496395.2023.2216370
DO - 10.1080/01496395.2023.2216370
M3 - Article
AN - SCOPUS:85160922625
SN - 0149-6395
VL - 58
SP - 1893
EP - 1907
JO - Separation Science and Technology
JF - Separation Science and Technology
IS - 11
ER -