title: Synthesis of Minerals with Iron Oxide and Hydroxide Contents as a Sorption Medium to Remove Arsenic from Water for Human Consumption.
abstract: Arsenic has been classified as a toxic and carcinogenic chemical element. It therefore presents a serious environmental problem in different regions of the country and the world. In the present work, two adsorbent media were developed and evaluated to remove arsenic from water in the Pájaro Verde mine shaft, Huautla, Tlaquiltenango, Morelos. The media were synthesized and characterized, obtaining a surface area of 43.04 m²·g(-1) for the goethite and 2.44 m²·g(-1) for silica sand coated with Fe(III). To conduct the sorption kinetics and isotherms, a 2³ factorial design was performed for each medium in order to obtain the optimal conditions for the factors of arsenic concentration, pH and mass of the adsorbent. The best results were obtained for goethite, with a removal efficiency of 98.61% (C₀ of As(V) 0.360 mg·L(-1)), and an effluent concentration of 0.005 mg·L(-1), a value that complies with the modified Official Mexican Standard NOM-127-SSA1-1994 [1] and WHO guidelines (2004) [2]. The kinetic equation that best fit the experimental data was the pseudo-second-order, resulting in the highest values for the constants for synthetic goethite, with a rate constant sorption of 4.019·g·mg(-1)·min(-1). With respect to the sorption isotherms, both media were fitted to the Langmuir-II linear model with a sorption capacity (qm) of 0.4822 mg·g(-1) for goethite and 0.2494 mg·g(-1) for silica sand coated with Fe(III).
authors.affiliation: Instituto Mexicano de Tecnología del Agua, Paseo Cuahnáhuac 8532, Col. Progreso, Jiutepec, CP. 62550 Morelos, México. sgarrido@tlatloc.imta.mx.
authors.forename: Sofia
authors.initials: S
authors.lastname: Garrido-Hoyos
authors.affiliation: Universidad Politécnica del Estado de Morelos, Paseo Cuauhnáhuac 566, Col. Lomas del Texcal, Jiutepec, CP. 62550 Morelos, México. ambiental.romero@gmail.com.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Romero-Velazquez
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000032:analysis / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000737:chemistry*; D058085:Iron Compounds / Q000737:chemistry*; D007700:Kinetics; D008903:Minerals / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D005290:Ferric Compounds; D006878:Hydroxides; D058085:Iron Compounds; D008903:Minerals; D014874:Water Pollutants, Chemical; C094886:goethite; C000499:ferric oxide; D012822:Silicon Dioxide; D001151:Arsenic
keywords: adsorbent media; arsenic; experimental design; isotherm; kinetic