TY - JOUR
T1 - A study on the adsorption of methylene blue onto gum ghatti/TiO2 nanoparticles-based hydrogel nanocomposite
AU - Mittal, Hemant
AU - Ray, Suprakas Sinha
N1 - Funding Information:
The authors are grateful to the National Research Foundation for awarding a postdoctoral research fellowship to Dr. Hemant Mittal (NRF-083640). The authors thank the University of Johannesburg , the Department of Science and Technology ( HGERA8X ) and the Council for Scientific and Industrial Research ( HGER20S ) for financial support. They also sincerely thank the DST-CSIR National Centre for Nanostructured Materials characterization and testing facility team who facilitated the characterization of the neat polymer, hydrogel and composite hydrogel samples.
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/7/1
Y1 - 2016/7/1
N2 - The objective of this work was to study the isotherm and kinetic models for the adsorption of methylene blue (MB) onto a TiO2 nanoparticle (TiO2NP)-containing hydrogel nanocomposite (HNC) of polyacrylamide-grafted gum ghatti (PAAm-g-Gg). The grafting of PAAm onto Gg was conducted using N,N'-methylene-bis-acrylamide (MBA) as a crosslinker, and different weight percentages of TiO2NPs were incorporated into the hydrogel matrix during the grafting reaction. The graft co-polymerization and the formation of the HNC were confirmed using FTIR, XRD, BET, SEM, TEM and EDS analyses. The adsorption of MB was studied in batch mode and it was found to be highly dependent on solution pH, ionic strength temperature and adsorbent loading. The MB-adsorption process followed the pseudo-second-order rate model and Langmuir adsorption isotherm with a maximum adsorption capacity of 1305.5 mg g-1. Thermodynamic studies revealed that the adsorption of MB onto the HNC surface was spontaneous, endothermic and through a process of physisorption. The results also showed that the HNC was much more effective for the adsorption of cationic dyes than anionic dyes, and it retained its original adsorption capacity for five successive cycles of adsorption-desorption. In conclusion, the hydrogel nanocomposite showed huge potential for remediating industrial wastewater polluted by toxic cationic dyes.
AB - The objective of this work was to study the isotherm and kinetic models for the adsorption of methylene blue (MB) onto a TiO2 nanoparticle (TiO2NP)-containing hydrogel nanocomposite (HNC) of polyacrylamide-grafted gum ghatti (PAAm-g-Gg). The grafting of PAAm onto Gg was conducted using N,N'-methylene-bis-acrylamide (MBA) as a crosslinker, and different weight percentages of TiO2NPs were incorporated into the hydrogel matrix during the grafting reaction. The graft co-polymerization and the formation of the HNC were confirmed using FTIR, XRD, BET, SEM, TEM and EDS analyses. The adsorption of MB was studied in batch mode and it was found to be highly dependent on solution pH, ionic strength temperature and adsorbent loading. The MB-adsorption process followed the pseudo-second-order rate model and Langmuir adsorption isotherm with a maximum adsorption capacity of 1305.5 mg g-1. Thermodynamic studies revealed that the adsorption of MB onto the HNC surface was spontaneous, endothermic and through a process of physisorption. The results also showed that the HNC was much more effective for the adsorption of cationic dyes than anionic dyes, and it retained its original adsorption capacity for five successive cycles of adsorption-desorption. In conclusion, the hydrogel nanocomposite showed huge potential for remediating industrial wastewater polluted by toxic cationic dyes.
KW - Adsorption kinetics and isotherms
KW - Methylene blue
KW - Polyacrylamide-grafted gum ghatti hydrogel nanocomposite
UR - http://www.scopus.com/inward/record.url?scp=84961689544&partnerID=8YFLogxK
U2 - 10.1016/j.ijbiomac.2016.03.032
DO - 10.1016/j.ijbiomac.2016.03.032
M3 - Article
C2 - 26997239
AN - SCOPUS:84961689544
SN - 0141-8130
VL - 88
SP - 66
EP - 80
JO - International Journal of Biological Macromolecules
JF - International Journal of Biological Macromolecules
ER -
