A new biosorbent based on Nostoc commune (NC) cyanobacteria, chemically modified with NaOH (NCM), has been prepared, characterized and tested as an effective biomass to remove Pb(II) in aqueous media. The adsorption capacity of NCM was determined to be q_e = 384.6 mg g⁻¹. It is higher than several other biosorbents reported in the literature. Structural and morphological characterization were performed by FTIR, SEM/EDX and point zero of charge pH (pH_PZC) measurements. NCM biosorbent showed more porous surfaces than those NC with heterogeneous plates including functional adsorption groups such as OH, C = O, COO⁻, COH or NH. Optimal Pb(II) adsorption occurred at pH 4.5 and 5.5 with a biomass dose of 0.5 g L⁻¹. The experimental data of the adsorption process were well fitted with the Freundlich-isotherm model and pseudo-2nd order kinetics, which indicated that Pb(II) adsorption was a chemisorption process on heterogeneous surfaces of NCM. According to the thermodynamic parameters, this process was exothermic (∆H⁰ < 0), feasible and spontaneous (∆G⁰ < 0). NCM can be regenerated and efficiently reused up to 4 times (%D > 92%). NCM was also tested to remove Pb (%R~98%) and Ca (%R~64%) from real wastewater.

In this study, cladodes of Opuntia ficus indica (OFIC), chemically modified with NaOH (OFICM), have been prepared, characterized, and tested as an effective biomass to remove Pb(II) and/or Cd(II) from aqueous media. At an optimum pH of 4.5, the adsorption capacity, q_e, of treated OFICM was almost four times higher than that of untreated OFIC. The maximum adsorption capacities (q_max) in the single removal of Pb(II) and Cd(II) were 116.8 and 64.7 mg g⁻¹, respectively. These values were 12.1% and 70.6% higher than those for the corresponding q_max in binary removal, which indicates the strong inhibitive effect of Pb(II) on the co-cation Cd(II) in a binary system. Structural and morphological characterization have been carried out by FTIR, SEM/EDX, and point of zero charge (pH_PZC) measurements. The SEM/EDX results confirmed that the metals are adsorbed on the surface. The presence of C-O, C=O, and COO- functional groups were identified by FTIR on both OFIC and OFICM surfaces. On the other hand, we found that the adsorption processes followed the pseudo-second-order kinetics for both single and binary systems, with a fast biosorption rate of Pb(II) and Cd(II). The equilibrium data (adsorption isotherms) were better described by Langmuir and modified-Langmuir models for single and binary systems, respectively. A good regeneration of OFICM was obtained with an eluent of 0.1 M HNO₃. Therefore, OFICM can be efficiently reused to remove Pb or Cd, up to three times.

Theobroma cacao is the main raw material to produce chocolate, as well as for use in the food, cosmetic, and pharmaceutical industries. However, Moniliophthora roreri is one of the most destructive fungal diseases and the main limiting of cacao production worldwide. Thus, this work aimed to assess the inhibitory effect of extracts of Zingiber officinale (T1) and Aloe vera (T2), and Trichoderma harzianum + Bacillus subtillis. (T3) on Moniliophthora roreri infection in Theobroma cacao; in addition, a control (T4) was also evaluated. Each treatment was applied to six plants of cacao. Incidence of monilia infection and fruit weight were monitored every 15 days (in total four periods) after the application of the treatment by spray. Significant differences (P<0.05) were found among treatments for incidence. It was observed that spraying entire cacao trees after two times (approximately 30 days) showed a reduction of monilia infection. After all periods, T1, T2, and T3 showed an incidence of monilia infection by 20.5, 17.7, and 14.9% respectively, compared to cultural control of 41.1%. This reduction of moniliasis infection translates into an increase in fruit weight average for T3 (8.4 kg), T2 (7.3 kg), and T1 (6.9 kg). In contrast, in the control (T3), the fruit weight average decreased by 5.3 kg. Biological control showed efficient management of pathogens as M. roreri. It is recommended to use such antifungal (Aloe vera) spray over at least 120 days which would decrease infection incidence even more.

Isla de Calor Urbana Superficial para Tres Megaciudades en África

Descrevemos os resultados do estudo da profundidade ótica do aerossol (POA) e do Forçamento Radiativo Direto (FRD) no topo da atmosfera (TOA), obtidos durante a campanha de medição e monitoramento, XXI Expedição Antártica do Peru, entre os meses de janeiro e fevereiro de 2013, e na área metropolitana de Huancayo (AMH) entre os meses de junho e julho de 2019. Na Estação Antártica Peruana Machu Picchu utilizou-se um fotômetro solar SP02-L. Tal instrumento possui 4 canais: 412 nm, 500 nm, 675 nm e 862 nm, permitindo realizar medições diretas do espectro de radiação visível. Na AMH usamos o sensor BF5, que mede a radiação direta, difusa e global em comprimento de onda curta. Os cálculos de AOD em latitudes polares variaram entre 0,0646 e 0,1061. Na AMH apresenta valor máximo de 0,58 (11 de junho) e mínimo de 0,19 (12 de junho). Determinou-se o coeficiente de Angstrom variando de 0 a 0,07, esses valores indicam a presença de partículas grandes. Na AMH varia de 0 a 1,8, que indica a presença de aerossóis de fonte de queima de biomassa e industrial. As propriedades óticas observadas foram usadas para estimar a forçante radiativa direta por aerossóis (FRDA) no topo da atmosfera. Os resultados indicam que no King George Island, o FRDA, está entre -2 e 4 W/m2; já para a AMH a forçante radiativa direta de aerossol está entre 0 e 20 W/m2.

El monitoreo de los sólidos disueltos totales (TDS) en el agua es crucial para asegurar su calidad, especialmente en fuentes destinadas al consumo humano. Esta investigación se centró en determinar las concentraciones de TDS en el agua utilizada por la comunidad de San Juan de Pillo, Acraquia. Se llevó a cabo un estudio cuantitativo con diseño de campo, recolectando muestras de un canal de riego en dos periodos de 2024: enero, con mayor caudal, y abril, con menor caudal. Se realizaron 12 muestreos en tres horarios diferentes cada semana durante cuatro semanas. Los resultados se analizaron utilizando la prueba de hipótesis "t" de Student, encontrando diferencias significativas en los niveles de TDS entre los meses estudiados. Estos hallazgos subrayan la necesidad de un monitoreo continuo para garantizar el acceso a agua potable segura, ya que las concentraciones de TDS no cumplen con los estándares del decreto supremo 004-2017 del Ministerio del Ambiente del Perú.