Examinando por Autor "Cuevas Gimenez, Juan Pablo"

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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
Soil management in Lepidium meyenii (maca) monoculture: trends and challenges for small farmers around Lake Chinchaycocha in the Andean highlands of Junin (Peru)
(Frontiers Media S.A., 2025-01-17) Solórzano Acosta, Richard; Chanco, Mirella; Seminario, Martín; Camel Paucar, Vladimir Fernando; Cabello Torres, Rita; Lastra Paucar, Sphyros Roomel Luciano; Arias Arredondo, Alberto Gilmer; Verástegui Martínez, Patricia; Quispe Matos, Kenyi Rolando; Carbajal Llosa, Carlos Miguel; Cuevas Gimenez, Juan Pablo; Cruz Luis, Juancarlos Alejandro; Turín Canchaya, Cecilia Claudia
Introduction: Monoculture is a significant concern due to its negative impact on soil quality, resource productivity, and agricultural sustainability, particularly in vulnerable communities. This research aims to evaluate high Andean soil management for maca monoculture. Materials and methods: To this end, interviews were conducted with maca farmers adjacent to Lake Chinchaycocha. The effect on soil quality was evaluated based on principal component analysis (PCA), weighted soil quality index (SQIw), and physico-chemical characteristics. Results: The results indicated differences between farmers in agronomic management, monoculture period (from 5 to 9 years), and fallow time (up to 10 years in the best cases). Regarding soil quality, the PCA highlighted boron andtotal nitrogen locations in the same quadrant, with the highest contribution to the analysis. Finally, the SQIw showed that soils without maca cultivation presented better quality. Conclusion: This research’s results indicate a need to optimize soil management practices, especially for small farmers, who are the most vulnerable group. In addition, further studies on boron and nitrogen availability in soils cultivated with maca are required, emphasizing areas that exceed 10 years of continuous use.