Examinando por Autor "Velarde Apaza, Lelie Diana"

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Aqueous-Medium Arsenic(V) Removal Using Iron Oxide-Coated Ignimbrite
(MDPI, 2024-12-28) Velarde Apaza, Lelie Diana; Chávez Collantes, Azucena; Solorzano Acosta, Richard; Cuevas Gimenez, Juan Pablo; Villanueva Salas, José Antonio
Arsenate As(V) is a toxic contaminant commonly found in aquifers and groundwater that poses significant risks to human health. The effective treatment of arseniccontaminated water is therefore crucial for safeguarding public health. This study investigates removing As(V) using iron oxide-coated ignimbrite in batch experiments by varying the adsorbent dosage, initial As(V) concentration, contact time, and system temperature. The adsorption experiments revealed that the Langmuir isotherm model better fit the data (R2 = 0.99) than the Freundlich model (R2 = 0.73). According to the Langmuir model, the maximum adsorption capacity of As(V) on the iron oxide-coated ignimbrite was 4.84 mg·g −1 ± 0.12 mg·g −1 of As(V), with a standard deviation of ±0.05 mg·g −1 after 2 h of exposure with 0.15 g/50 mL iron oxide-coated ignimbrite adsorbent concentration. In the kinetic analysis, the pseudo-first-order model best described the adsorption process at 283 K, 293 K, and 303 K, although the pseudo-second-order model also showed an adequate fit, particularly at 293 K. This indicates that, while the pseudo-first-order model is generally more suitable under these conditions, the pseudo-second-order model may also apply under certain circumstances. The results of the batch experiments demonstrate that iron oxide-coated ignimbrite is a promising adsorbent for effectively reducing high concentrations of As(V) in contaminated water
Chlorella sp. inoculum doses affect ethinylestradiol removal in a wastewater treatment plant in the Peruvian Andes
(Universidade Estadual de Maringá (UEM), Brasil, 2025-06-17) Chávez Collantes, Azucena; Solórzano Acosta, Richard Andi; Velarde Apaza, Lelie Diana; Campos Ruiz, Joseph; Alva Plasencia, Edin Edgardo; Castillo Rojas, Eisner Will
The microalgae Chlorella sp. have demonstrated efficiency in the removal of pharmaceutical contaminants. However, there is no agreement on the inoculum dose since it depends on the contaminant concentration and other very specific parameters in each case. This study aims to evaluate the effect of Chlorella sp. inoculum doses on ethinylestradiol (EE) removal from wastewater treatment plant effluent in Celendín district of the province of Celendín, Cajamarca region, Peru. Four doses of inoculum (0, 100, 200, and 300 mL) were tested at a 2,1x10⁶ cell∙mL⁻¹ microalgae cell concentration and 4 mg∙L ⁻¹ of ethinylestradiol in photobioreactors. The final concentration of ethinylestradiol was determined after 20 days through High Performance Liquid Chromatography (HPLC). It was evidenced that a dose of 300 mL∙L ⁻¹ of Chlorella sp. could remove 96,49% of ethinylestradiol from wastewater, unlike the other tested concentrations, which were below 80,92% removal. It was concluded that at a higher dose of Chlorella sp. inoculum, a higher ethinylestradiol removal percentage was observed in a wastewater sample from a treatment plant in the Peruvian Andes.