TY - JOUR
T1 - Immobilization of exopolymeric substances from bacteria for metal removal
T2 - a study on characterization, optimization, reusability and toxicity
AU - Cheah, Caleb
AU - Cheow, Yuen Lin
AU - Yien Ting, Adeline Su
N1 - Funding Information:
This project was funded by the Malaysian Ministry of Education (MOE) under the FRGS grant scheme (FRGS/1/2018/STG03/MUSM/02/1).The authors are grateful to the Malaysian Ministry of Education (MOE) 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 project.
Funding Information:
This project was funded by the Malaysian Ministry of Education (MOE) under the FRGS grant scheme ( FRGS/1/2018/STG03/MUSM/02/1 ).
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2022/12/1
Y1 - 2022/12/1
N2 - This study investigated the immobilization of exopolymeric substances (EPS) from Bacillus cereus using sodium alginate to form EPS beads for metal removal. The EPS beads were characterized and their optimum biosorption conditions established (biosorbent dosage, initial metal concentration and pH of metal solutions). The EPS beads were also tested for reusability by using them continuously for five metal removal cycles with desorption process in between cycles. The toxicity of the treated metal solutions was tested by phytotoxicity tests. Results revealed that EPS beads demonstrated significantly higher metal removal efficiency (Pb: 99.26%, Cr: 50.73%, Cu: 48.94%, Zn: 29.81%, Cd: 20.29%) compared to plain alginate beads (without EPS) (Pb: 84.45%, Cu: 31%, Cr: 28.37%, Zn: 11.91%, Cd: 9.37%). SEM-EDX analysis detected Cu, Pb, Zn, Cd and Cr on the surface of EPS beads. Optimum conditions for Pb removal by EPS beads were from the use of 0.1 g of biosorbent at 100 mg/L initial metal concentration and pH 5. By contrast, Cu, Zn, Cd and Cr were optimally removed by 0.3 g of biosorbent at 25 mg/L initial metal concentration and pH 5. EPS beads can be reused up to five times while maintaining a high rate of metal removal efficiency (Pb- 99.52%, Cr- 89.23%, Cu- 89.17%, Zn-52.52%, Cd-39.12%). This was achieved through desorption with nitric acid that consistently recovered 76–93% of the metal adsorbed. FTIR analysis reveals that nitric acid is capable of restoring the functional groups present within EPS beads, allowing it to bind with metal ions in repeated cycles. Metal solutions treated with EPS beads were less toxic as seedling shoots (pre-treated: 0–10 cm, post-treated: 1.2–18.1 cm) and roots (pre-treated: 0–7.8 cm, post-treated: 0.8–15.1 cm) grew well, which suggested that reduced levels of metals led to reduced phytotoxicity. This study provides an insight into the use of EPS beads for metal removal, highlighting the benefits and reusability of the beads for future wastewater treatment.
AB - This study investigated the immobilization of exopolymeric substances (EPS) from Bacillus cereus using sodium alginate to form EPS beads for metal removal. The EPS beads were characterized and their optimum biosorption conditions established (biosorbent dosage, initial metal concentration and pH of metal solutions). The EPS beads were also tested for reusability by using them continuously for five metal removal cycles with desorption process in between cycles. The toxicity of the treated metal solutions was tested by phytotoxicity tests. Results revealed that EPS beads demonstrated significantly higher metal removal efficiency (Pb: 99.26%, Cr: 50.73%, Cu: 48.94%, Zn: 29.81%, Cd: 20.29%) compared to plain alginate beads (without EPS) (Pb: 84.45%, Cu: 31%, Cr: 28.37%, Zn: 11.91%, Cd: 9.37%). SEM-EDX analysis detected Cu, Pb, Zn, Cd and Cr on the surface of EPS beads. Optimum conditions for Pb removal by EPS beads were from the use of 0.1 g of biosorbent at 100 mg/L initial metal concentration and pH 5. By contrast, Cu, Zn, Cd and Cr were optimally removed by 0.3 g of biosorbent at 25 mg/L initial metal concentration and pH 5. EPS beads can be reused up to five times while maintaining a high rate of metal removal efficiency (Pb- 99.52%, Cr- 89.23%, Cu- 89.17%, Zn-52.52%, Cd-39.12%). This was achieved through desorption with nitric acid that consistently recovered 76–93% of the metal adsorbed. FTIR analysis reveals that nitric acid is capable of restoring the functional groups present within EPS beads, allowing it to bind with metal ions in repeated cycles. Metal solutions treated with EPS beads were less toxic as seedling shoots (pre-treated: 0–10 cm, post-treated: 1.2–18.1 cm) and roots (pre-treated: 0–7.8 cm, post-treated: 0.8–15.1 cm) grew well, which suggested that reduced levels of metals led to reduced phytotoxicity. This study provides an insight into the use of EPS beads for metal removal, highlighting the benefits and reusability of the beads for future wastewater treatment.
KW - Bacillus cereus
KW - Biosorption
KW - Exopolymeric substances
KW - Immobilization
KW - Wastewater treatment
UR - http://www.scopus.com/inward/record.url?scp=85138068976&partnerID=8YFLogxK
U2 - 10.1016/j.jenvman.2022.116244
DO - 10.1016/j.jenvman.2022.116244
M3 - Article
C2 - 36116257
AN - SCOPUS:85138068976
SN - 0301-4797
VL - 323
JO - Journal of Environmental Management
JF - Journal of Environmental Management
M1 - 116244
ER -