Efficient removal of lead from highly acidic wastewater by periodic ion imprinted mesoporous SBA-15 organosilica combining metal coordination and co-condensation

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 3; no. 18; pp. 9789 - 9798
• Main Authors: He, Rong, Li, Weiming, Deng, Dayi, Chen, Wensen, Li, He, Wei, Chaohai, Tang, Youwen
• Format: Journal Article
• Language: English
• Published: 01.01.2015
• Subjects: Adsorption; Atomic beam spectroscopy; Fourier transforms; Infrared spectroscopy; Lead (metal); Surface chemistry; Wastewater treatment; X-rays; China, People's Rep
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c5ta00820d

In order to develop a highly efficient method for direct removal of lead from acidic wastewater (pH 2.0), we introduce a novel highly ordered Pb super(2+) imprinted mesoporous silica (PbIMS) SBA-15 combining co-condensation and functionalized iminodiacetic acid (IDA). Fourier transform infrared spectroscopy (FTIR) and energy-dispersive X-ray (EDX) analysis provided the components of PbIMS. The solid-state super(13)C NMR spectra demonstrated the successful embedment of IDA in the mesoporous silica. Furthermore, X-ray photoelectron spectroscopy (XPS) analysis confirmed that Pb super(2+) was coordinated by the N atom and carboxyl O atom of IDA. The results of transmission electron microscopy (TEM), small angle X-ray diffraction (XRD) and N sub(2) adsorption-desorption measurement confirmed that the PbIMS preserved a highly ordered hexagonal P6mmmesostructure. The Brunauer-Emmett-Teller (BET) surface area was 762 m super(2) g super(-1). The saturated adsorption capacity of PbIMS toward lead reached up to 103 mg g super(-1) at pH 2.0, which was greater even than that of the simply modified SBA-15 by IDA at pH 4.5. The values of selectivity coefficients of PbIMS for six competing metal ions ranged from 67.3 to 12.7. The adsorption of Pb super(2+) reached equilibrium within 7 min. The adsorption efficiency of PbIMS was above 93% after six extraction-stripping cycles. The investigation conducted with real samples of strongly acidic wastewater demonstrated the ability of PbIMS to efficiently remove lead below the current China regulatory standard.