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Facile synthesis of amino-functional large-size mesoporous silica sphere and its application for Pb2+ removal

Li, Penggang, Wang, Jingxuan, Li, Xitong, Zhu, Wenjie, He, Sufang, Han, Caiyun, Luo, Yongming, Ma, Wenhui, Liu, Nengsheng, Dionysiou, Dionysios D.
Journal of hazardous materials 2019 v.378 pp. 120664
X-ray photoelectron spectroscopy, adsorption, arsenic, chromium, heavy metals, industrial wastewater treatment, infrared spectroscopy, lead, metal ions, models, nitrogen, pH, particle size, porous media, silica, thermal analysis, thermal stability, wastewater, zinc
Amino-functional large-size mesoporous silica spheres (LMS-AP) were successfully synthesized through a one-step method with (3-aminopropyl) triethoxysilane (APTES) addition during the pseudomorphic transformation process. LMS-AP were characterized using thermogravimetry-differential thermal analysis, Nitrogen adsorption-desorption measurement, infrared spectroscopy, and X-ray photoelectron spectroscopy. The study found that -NH2 was grafted into LMS, and the LMS-AP had a better thermal stability than other samples. The Pb2+ removal properties of LMS-AP were investigated using the static and dynamic experiments in simulated and real wastewater solutions. The kinetic and equilibrium experiments indicated that the adsorption process of LMS-AP fitted the Langmuir adsorption model and the pseudo-second-order kinetics model (R2 > 0.98), respectively. The maximum Qe (mg/g) was about 100 mg/g in the static adsorption condition. The adsorption mechanism of removal of Pb2+ was also investigated. In fix bed column experiments, LMS-AP exhibited excellent Pb2+ adsorption ability for simulated wastewater, with the maximum qe (mg/g) of 48.7 mg/g for particle size under 1–3 mm. Meanwhile in actual industrial wastewater treatment process, LMS-AP had a better Pb2+, Zn2+ and Cr (VI) removal efficiency of 80% and As (V) of 30–40% removal efficiency at initial pH 4, suggesting selective adsorption property for different heavy metal ions.