Sorption of Pb(II) from Aqueous Solutions by Acid-Modified Clinoptilolite-Rich Tuffs with Different Si/Al Ratios

Applied Sciences

MaríaT. Olguín¹  German Giácoman-Vallejos²  Mohamed Abatal³  Francisco Anguebes-Franseschi⁴  AtlV. Córdova Quiroz⁴  AméricaR. Vázquez-Olmos⁵  Joel Vargas⁶ 

[1] Departamento de Química, Instituto Nacional de Investigaciones Nucleares, Carretera México.Toluca s/n. La Marqueza, Ocoyoacac, C.P. 52750 Estado de México, Mexico;Facultad de Ingeniería, Universidad Autónoma de Yucatán, Av. Industrias no Contaminantes por Periférico Norte, Cordemex,C.P. 97310 Mérida, YUC, Mexico;Facultad de Ingeniería, Universidad Autónoma del Carmen, C.P. 24180 Ciudad del Carmen, Campeche, Mexico;Facultad de Química, Universidad Autónoma del Carmen, Calle 56 No. 4 Esq. Av. Concordia, Col. Benito Juárez, C.P. 24180 Ciudad del Carmen, Campeche, Mexico;Instituto de Ciencias Aplicadas y Tecnología, UNAM, Circuito Exterior, S/N, Ciudad Universitaria, A.P. 70-186, Delegación Coyoacán, C.P. 04510 Ciudad de México, Mexico;Instituto de Investigaciones en Materiales, Unidad Morelia, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex Hacienda de San José de la Huerta, C.P. 58190 Morelia, Michoacán, Mexico;

关键词: lead;    sorption;    natural zeolite;    clinoptilolite;    sulfuric acid;   

DOI  :  10.3390/app9122415

来源: DOAJ

【 摘 要 】

The removal of Pb(II) from aqueous solutions by acid-modified clinoptilolite-rich tuff was investigated in this work. Clinoptilolite-rich tuff samples were treated using H₂SO₄ at different concentrations. Prior to and following acid treatment, the samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FTIR). The pH of the point of zero charge (pH_PZC) was also determined as part of this characterization. Batch studies were studied to investigate Pb(II) removal as a function of contact time, initial Pb(II) concentration, adsorbent dosage, and solution pH. The results of the XRD and SEM techniques showed that clinoptilolite is the main mineral of the non- and acid-treated natural zeolite samples. However, EDS analysis indicated that the Si/Al ratio increases as the exchangeable ions decrease with increasing acid concentrations. The optimum conditions for Pb(II) removal for samples with 4.37 ≤ Si/Al ≤ 7.9 were found to be as follows: Contact time of 60−360 min, pH: 6−8, and adsorbent dose of 6 mg g⁻¹; whereas for acid-modified clinoptilolite-rich tuffs with 9.01 ≤ Si/Al ≤ 9.52, these conditions were as follows: Contact time of 1440 min, pH: 8−10, and adsorbent dose of 10 mg g⁻¹. The experimental data were analyzed by kinetic and isotherms models. The results showed that the sorption of Pb(II) on samples with Si/Al ratios of 4.37, 5.31, and 7.91 were in agreement with the pseudo-second order and Langmuir isotherm with q_m = 48.54, 37.04, and 14.99 mg g⁻¹, respectively, while the kinetic data and isotherm for samples with 9.01 ≤ Si/Al ≤ 9.52 were found to fit the pseudo-first order and Freundlich model.

【 授权许可】

Unknown