Lourdes Díaz-Jiménez

The excessive use of synthetic insecticides and the environmental stress in the crops led us to determine pest control by a biopesticide that induces the concentration of nordiguaracetic acid (NDGA), kaempferol and quercetin as defence activators in the potato crop. A biopesticide was applied to four potato genotypes: Fiana, Silvestre, Norteña and 09-37, under rainfed conditions, the repellent biopesticide was applied to the 16 DAE and the biofungicide to the 27 DAE, the concentration of kaempferol, quercetin and NDGA before applying the biopesticides was made at 14 DAE and the second sample was 37 DAE after applying the doses of the product, it was analyzed by completely random design with 4 treatments and 4 repetitions. The repellency of the potato flea beetle (Epitrix cucumeris), the concentration of ingredients in leaves and the absorption of the biopesticide were determined. The repellency at 27 DAE was 93.5% and at 37 DAE was 97.5%, there was no presence of diseases, at 14 DEA, no incidence of the ingredients was found in the crop, at 37 DAE, the 09-35 genotype had the highest concentration of NDAG with 558.75 mg/kg with 54.09% absorption and kaempferol with 135.92 mg/kg with absorption of 98%, the Silvestre variety with 9404.3 mg/kg with absorption of 64.37%, for the rest of the genotypes are significantly higher. The effect on repellency could be because the insect was not adapted to these ingredients and the absence of diseases to the defence activators and their absorption in the plant, so the plants did not show drought stress.

This study evaluates Fe₃O₄ magnetic biochar synthesized from pecan nutshells for arsenic removal. Surface modification with Fe₃O₄ significantly enhanced arsenic adsorption selectivity and efficiency compared to raw biomass (PM). Synthesis variables (precursor type, particle size, Fe/precursor ratio, N₂) and adsorption conditions (such as concentration, pH, agitation) were investigated. The modified biochar achieved >90% arsenic removal efficiency under various conditions, demonstrating the modification’s critical role. A fuzzy decision network was employed to analyze experimental results and identify optimal conditions for maximizing performance. This approach effectively leverages knowledge for scenario-specific optimization, offering a sustainable strategy for advanced water treatment materials.

Adequate treatment of the organic fraction of municipal solid waste (OFMSW) in co-digestion with sewage sludge (SS) through dark fermentation (DF) technologies has been widely studied and recognized. However, there is little experience with a high-solids approach, where practical and scalable conditions are established to lay the groundwork for further development of feasible industrial-scale projects. In this study, the biochemical hydrogen potential of OFMSW using a 7 L batch reactor at mesophilic conditions was evaluated. Parameters such as pH, redox potential, temperature, alkalinity, total solids, and substrate/inoculum ratio were adjusted and monitored. Biogas composition was analyzed by gas chromatography. The microbial characterization of SS and post-reaction percolate liquids was determined through metagenomics analyses. Results show a biohydrogen yield of 38.4 NmLH₂/gVS OFMSW, which forms ~60% of the produced biogas. Aeration was proven to be an efficient inoculum pretreatment method, mainly to decrease the levels of methanogenic archaea and metabolic competition, and at the same time maintain the required total solid (TS) contents for high-solids conditions. The microbial community analysis reveals that biohydrogen production was carried out by specific anaerobic and aerobic bacteria, predominantly dominated by the phylum Firmicutes, including the genus Bacillus (44.63% of the total microbial community), Clostridium, Romboutsia, and the phylum Proteobacteria, with the genus Proteus.

Arsenic contamination in water demands effective, low-cost removal methods. This study introduces nanomagnetite-coated biochar derived from pecan nutshells for efficient arsenic adsorption. Utilizing a solvothermal method, uniform magnetite crystals were grown on biochar in a controlled process at 200 °C. The resulting bioadsorbent, characterized by XRD, SEM, and FTIR, exhibited a narrow size distribution and consistently high arsenic removal rates (97.30–98.76%). Biochar with varied particle sizes, synthesized at a short reaction time (6 h), showed the highest removal efficiency of arsenic (98.76%) and adsorption capacity (7.974 mg/g). This approach offers a sustainable for arsenic remediation, and ease of magnetic separation.

Biopesticides are alternatives to synthetic ones, repel insects and control diseases in a sustainable way. The objective was to evaluate the efficiency and efficacy of a biopesticide. In apples in 2023 and walnut in 2024, both in Coahuila, Mexico. In 2023, with: A.- Without application and B.- With application of 2 L of biopesticide one liter at the beginning and the second 10 days later, with three repetitions. In Walnut A.- With synthetic insecticide and fungicide and B.- With the application of the biopesticide. The repellency index at 20 days after application (DDA) the control reached 5.3 and the biopesticide with 1 butterfly, the repellency index at 20 DDA, 0.39 and the effectiveness of the biopesticide was 75.3%. In walnut, the repellency of the synthetic was 0.25 at 20 DDA and of the biopesticide was 1.5. In apple tree diseases, the severity without application was 6.75 % and the biopesticide 1.67 %, in walnut with synthetic the severity was 2.0 % and the biopesticide 5.21, %, the effectiveness of the biopesticide was 61.6%. The repellency is less than one and the effectiveness is greater than 60% with Mexican standards.