Yakov Felipe Carhuarupay-Molleda

Various tubers are cultivated in the Peruvian Andes. Olluco (Ullucus tuberosus) is consumed locally for its culinary qualities and nutritional value. In addition to its resistance to pests and extreme climatic conditions, this Andean tuber is an important source of starch. In this study, the extraction and characterization of the physical, chemical, technofunctional, and thermal properties of olluco starches from the Puka cheqche papalisa (PCP), Bela api chuqcha lisa (BACL), and Q’ello muro lisa (QML) varieties were conducted, with samples collected in 2024. Extraction yields ranged from 3.00 to 4.45%, viscosities from 6443.17 to 6892.77 cP, a high whiteness index from 90.43 to 93.52, water activity less than 0.55, and a heterogeneous particle size distribution. Amylose content ranged from 31.00 to 33.33%. FTIR analysis revealed similar functional groups and structural bonds across the varieties. For technofunctional properties, the QML variety exhibited greater water absorption, a higher solubility index, and greater swelling power. Pasting temperatures ranged from 68.70 to 71.10 °C, with low retrogradation. Thermal analysis showed good thermal stability from 104.46 to 268.42 °C, a low gelatinization temperature from 59.37 to 60.19 °C, and an enthalpy of up to 5.5757 J/g. Olluco starches have high potential for industrial applications, and their ease of cultivation makes them ideal for starch extraction.

Anthropogenic activities generate waste that negatively impacts the environment, especially water resources, due to the accumulation of heavy metal ions. Several adsorption methods have been developed, including the use of natural materials such as algae and activated clay. This study aimed to evaluate the effect of pH on batch adsorption of heavy metal ions using Nostoc sphaericum hydrocolloid (HA)/activated nanoclay (NR) composites. The NR/HMB-HA and NR/HUT-HA composites were prepared with a 2:8 mass ratio of HA and NR, using types of clay with code HMB and HUT, previously activated with 1 M NaCl and acid treatment. The adsorption capacity was evaluated using batch tests at pH 4.5 and 5.5, analyzing the removal percentage, adsorption kinetics, adsorption isotherms, and regeneration cycles for unimetal and multimetal systems. The composites present a load point close to 5.1. The FTIR analysis showed changes in the intensity of functional groups following adsorption, confirming the interaction with metallic ions. Both composites showed high affinity in multimetallic systems, especially at pH 5.5, with high selectivity for Pb²⁺ (≈99% removal), followed by As, Cd, and Zn, from an initial concentration of 10 ppm for each metal ion. Equilibrium is reached in approximately 90 min, allowing adsorption of up to 69.9% after five regeneration cycles in a multimetal system. The kinetic study showed that multimetal absorption at equilibrium is governed by chemisorption processes in the order Pb > As > Zn > Cd, with q_e values between 0.392 and 0.058 mmol/g and diffusivity from 15.506 × 10¹¹ to 1.692 × 10¹¹ m²/s. Likewise, the isotherms study indicated a favorable process with maximum adsorption (q_max) between 16.696 and 5.223 mmol/g at pH 5.5. Altogether, the developed composites show high potential for the removal of heavy metals in contaminated waters, in addition to their high reuse capacity.

Este estudio evaluó la eficiencia de los biocoagulantes naturales P. serotina y M. germanica en la remoción de turbidez y sólidos suspendidos totales (SST) en un río en Apurímac, Perú. Se aplicó un diseño factorial 3×2×2, considerando tres dosis de biocoagulante (0,1; 0,5 y 1,0 g/500 mL), dos velocidades de agitación (50 y 150 rpm) y dos tiempos de sedimentación (30 y 60 min), con tres repeticiones por tratamiento. Se mostraron reducciones significativas, alcanzando valores máximos de 92,71 % en turbidez y 90,92 % en SST con M. germanica, y de 90,16 % en turbidez y 88,73 % en SST con P. serotina. El análisis de varianza (ANOVA) confirmó que la dosis y el tiempo de sedimentación influyeron significativamente en la remoción de turbidez y SST (p < 0,05), mientras que la velocidad de agitación resultó relevante únicamente en P. serotina. Estos hallazgos evidencian que los extractos de semillas de P. serotina y M. germanica constituyen alternativas viables, sostenibles y de bajo costo para el tratamiento de aguas en comunidades rurales andinas.

Cultural customs often condition solid waste management, especially in developing countries. The decomposition of solid waste depends on climatic conditions and is related to geomorphology and anthropogenic practices. Leachate generated in landfills can migrate superficially and underground, contaminating soils and aquifers. Knowing the level of contaminant load in leachate is important for proper solid waste management. However, in the Andean regions of Peru, there is scarce data on the polluting potential of leachates. This research aimed to determine the Leachate Pollution Index (LPI) according to the sub-indexes of organic, inorganic, and heavy metals from landfills in the high Andean regions of Peru. Physical, chemical, and microbiological parameters were evaluated in fresh and retained leachate samples, in both dry and rainy seasons, from two landfills located at around 3000 m of altitude. The results showed high contamination levels, particularly in BOD₅, COD, NH₃-N, and total coliforms, with high organic and inorganic sub-indexes that affect the LPI, indicating high levels of contamination and posing a potential risk to surrounding ecosystems. It was also found that the high Andean landfills studied have a good-to-high biodegradability. This research contributes essential baseline information for environmental monitoring and supports the need for improved leachate management in high-altitude landfills in Peru and similar Andean contexts.

Dye residues from the textile industry constitute a critical wastewater problem. This study aimed to evaluate the removal capacity of methylene blue (MB) in aqueous media, using an adsorbent formulated from activated and sonicated nanoclay (NC) and microatomized Nostoc sphaericum (ANS). NC was obtained by acid treatment, followed by activation with 1 M NaCl and sonication, while ANS was obtained by microatomization in an aqueous medium. NC/ANS was mixed in a 4:1 weight ratio. The NC/ANS synergistic adsorbent was characterized by the point of zero charge (PZC), zeta potential (ζ), particle size, FTIR spectroscopy, and scanning electron microscopy (SEM). NC/ANS exhibited good colloidal stability, as determined by pH_PZC, particle size in the nanometer range, and heterogeneous morphology with functional groups (hydroxyl, carboxyl, and amide), removing between 72.59 and 97.98% from an initial concentration of 10 ppm of MB, for doses of 20 to 30 mg/L of NC/ANS and pH of 5 to 8. Optimal adsorption conditions are achieved at pH 6.8 and 32.9 mg/L of adsorbent NC/ANS. It was observed that the pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models best described the adsorption kinetics, indicating a predominance of the physisorption process, with adsorption capacity around 20 mg/g. Isotherm models and thermodynamic parameters of adsorption, ΔS, ΔH, and ΔG, revealed that the adsorption process is spontaneous, favorable, thermodynamically stable, and occurs at the monolayer level, with a regeneration capacity of 90.35 to 37.54% at the fifth cycle. The application of physical activation methods, such as sonication of the clay and microatomization of the algae, allows proposing a novel and alternative synergistic material from organic and inorganic sources that is environmentally friendly and promotes sustainability, with a high capacity to remove cationic dyes in wastewater.

Lentic ecosystems are highly vulnerable to anthropogenic disturbances, which can lead to ecological imbalances with the loss of native biodiversity. This research evaluated the impact of anthropogenic activities on water quality and the trophic status of the Pacucha Lagoon, Andahuaylas, Apurimac. Seasonal sampling was conducted at six strategic points on the surface and bottom of the lake, following standardized protocols, during both the dry and rainy seasons. Physical and chemical parameters, metal ions, chlorophyll-a, and trophic status were determined using the Carlson indices, and water quality was assessed through the WQI-PE. The quantification of anthropogenic impacts was performed using the Leopold matrix. Statistical analysis included descriptive methods, ANOVA, Pearson correlation, and PCA at 5% significance. The results classify the lake as having “Regular” water quality according to WQI-PE. Physical and chemical parameters remain within the Environmental Quality Standards (ECA-Peru), while heavy metal ions exceed the limits in both seasons. The system exhibits mesotrophic conditions that tend to become eutrophic during the rainy season, suggesting a favorable nutrient balance for biological productivity. Activities with the most significant adverse impacts include agricultural practices that involve the intensive use of agrochemicals, morphological alterations to the surrounding area, and unregulated aquaculture. The lack of effective regulatory mechanisms and a lack of commitment to conservation suggest a high risk of irreversible degradation of the Pacucha Lagoon ecosystem.

The aim of this study was to evaluate the removal of Pb and As from an aqueous solution using corn residue cellulose nanocrystals (NCCs). The corn husk was subjected to alkaline digestion, followed by bleaching and esterification with 3% citric acid to obtain NCCs. A 10 ppm multimetal solution of Pb and As was prepared. The adsorption process was evaluated by adjusting the pH and NCC dosage, optimized through the nonlinear regression of empirical mathematical models. Based on the optimal parameters, the kinetics were evaluated using the PFO and PSO models. The NCCs displayed nanometer-level characteristics with a particle size less than 383.7 nm, a ζ potential in the range of −28–70 mV, pH_ZCP with an acidic tendency, a porous crystal structure as evaluated through SEM images, and the presence of functional groups with a high chelating capacity, as identified via FTIR. Optimum values of pH 8.0 and 20 mg/L of the NCC dose were found, from which it was observed that the PFO, PSO, and Elovich kinetics showed R² > 0.974, with an adsorption capacity in the order Pb > As. The adsorbent-formulated NCCs presented a good capacity to remove heavy metals from aqueous media.

Objective: The objective of this study was to evaluate the removal of Pb and As in aqueous media by activated clay (AC). Theoretical Framework: Heavy metals in water represent a risk to health and ecosystems, their removal through new materials is a challenge for the industry. Method: The methodology adopted for this research comprises in that natural clay (NC) was activated with sodium chloride and phosphoric acid followed by sonication. A synthetic solution of Pb and As was prepared at different pH. Results and Discussion: The zero charge point was found to be 7.10 for AC and 8.02 for NC, the ζ potential was found to be between - 41.15 and - 45.43 mV in the pH range of 4 to 12, with degree of crystallinity of 97.24% and crystal size of 2.85 nm determined by XRD. FTIR analysis allowed the identification of functional groups with chelating capacity. Was observed As removal of 75.51% (110.40 mg/g) and 23.23% (58.13 mg/g) and 97.75% (106.41 mg/g) and 100.0% (206.53 mg/g) for Pb with AC and NC respectively at pH 6 and 8. Research Implications: Los reaultadoe encontrados sugieren que la arcilla activada se convierte en un material alta capacidad de adsorción de metales pesados en sistemas multimetal. Esta cualidad se debe al incremtno de grupos funionales en su superficie y al tamaño nanométrico que incrementa el área de contacto. Originality/Value: Activation of the clay with sodium chloride and weak acid followed by sonication is an environmentally friendly process that produces a material with high heavy metal removal capacity in aqueous media.

Aqueous suspensions rely on electrostatic interactions among suspended solids, posing a significant challenge to maintaining stability during storage, particularly in the food and pharmaceutical industries, where synthetic stabilizers are commonly employed. However, there is a growing interest in exploring new materials derived from natural and environmentally friendly sources. This study aimed to optimize the stability parameters of a novel Altoandino Nostoc Sphaericum hydrocolloid (NSH) extracted via micro atomization. Suspensions were prepared by varying the pH, gelatinization temperature and NSH dosage using a 2³ factorial arrangement, resulting in eight treatments stored under non-controlled conditions for 20 days. Stability was assessed through turbidity, sedimentation (as sediment transmittance), ζ potential, particle size, color and UV-Vis scanning. Optimization of parameters was conducted using empirical equations, with evaluation based on the correlation coefficient (R²), average relative error (ARE) and X². The suspensions exhibited high stability throughout the storage period, with optimized control parameters identified at a pH of 4.5, gelatinization temperature of 84.55 °C and NSH dosage of 0.08 g/L. Simulated values included turbidity (99.00%), sedimentation (72.34%), ζ potential (−25.64 mV), particle size (300.00 nm) and color index (−2.00), with simulated results aligning with practical application. These findings suggest the potential use of NSH as a substitute for commercial hydrocolloids, albeit with consideration for color limitations that require further investigation.