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Two-step preparation of amidoxime-functionalized natural zeolites hybrids for the removal of Pb2+ ions in aqueous environment
Puspitasari T.a,b, Kadja G.T.M.a, Radiman C.L.a, Darwis D.b, Mukti R.R.a
a Division of Inorganic and Physical Chemistry, Institut Teknologi Bandung, 40132, Indonesia
b Center for Application Isotopes and Radiation (CAIR) – BATAN, Jakarta, 12440, Indonesia
[vc_row][vc_column][vc_row_inner][vc_column_inner][vc_separator css=”.vc_custom_1624529070653{padding-top: 30px !important;padding-bottom: 30px !important;}”][/vc_column_inner][/vc_row_inner][vc_row_inner layout=”boxed”][vc_column_inner width=”3/4″ css=”.vc_custom_1624695412187{border-right-width: 1px !important;border-right-color: #dddddd !important;border-right-style: solid !important;border-radius: 1px !important;}”][vc_empty_space][megatron_heading title=”Abstract” size=”size-sm” text_align=”text-left”][vc_column_text]© 2018Amidoxime-functionalized natural zeolites hybrids were prepared through two-step method including γ-irradiation for the grafting polymerization of polyacrylonitrile (PAN) and chemical transformations of nitrile groups (–R–C≡N) to amidoxime groups (–R–C(NH2) = NOH). This study aims to combine the good mechanical properties of low-cost inorganic matrices, i.e. natural zeolites, with strong chelating ability, which is potential for adsorbing toxic metal cations, especially Pb2+. The grafting polymerization of PAN depended on the γ-irradiation dose and dose rate. The optimized condition for the highest degree of grafting (20%) and maintained zeolites structure lies at the irradiation dose of 100 kGy at a dose rate of 2 kGy h−1. It was indicated that the grafting polymerization of PAN also occurred inside the micropores since the micropore volumes cannot be detected by N2 adsorption-desorption isotherms after grafting polymerization and chemical transformations. Moreover, the grafted PAN probably formed a chemical bonding with the zeolites since they exhibited the peaks of ≡Si–O[rad] and ≡Si[rad] sites in the ESR spectra of zeolites after γ-irradiation. The amidoxime-functionalization was confirmed by FTIR spectroscopy which showed the transformation of C≡N band into C=N, C–N and N–OH bands and SEM-EDX which exhibited the morphology alteration and the enhancement of C and N atoms percentage. The two-step preparation appeared to not alter the structure of zeolites as shown by XRD and 27Al MAS NMR spectroscopy. The amidoxime-functionalized natural zeolites hybrids exhibited maximum adsorption capacity of 72 mg g−1 towards Pb2+ in the aqueous environment which was comparable and, even, higher than several previous reports. The adsorption process followed the Langmuir model with favorable adsorption based on the separation factor values, while the adsorption kinetics are based on pseudo-second order model.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Author keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Adsorption capacities,Chemical transformations,Functionalizations,Grafting polymerization,MAS-NMR spectroscopy,Optimized conditions,Polyacrylonitrile (PAN),Pseudo-second order model[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Indexed keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Amidoxime-functionalization,Grafting polymerization,Pb2+ adsorption,Zeolites,γ-irradiation[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Funding details” size=”size-sm” text_align=”text-left”][vc_column_text]TP and GTMK thank the Ministry of Research, Technology and Higher Education (Kemenristekdikti), Republic of Indonesia, for the post graduate and PMDSU scholarships, respectively. The authors thank the late Mr. R. Sugianto from Minatama Company for providing us the natural zeolites. This research is partially funded by Hibah Program Penelitian, Pengabdian kepada Masyarakat dan Inovasi (P3MI) 2017 and in-house project of CAIR-BATAN .[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”DOI” size=”size-sm” text_align=”text-left”][vc_column_text]https://doi.org/10.1016/j.matchemphys.2018.05.083[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/4″][vc_column_text]Widget Plumx[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][/vc_column][/vc_row]