Objective: To determine the optimum pH at which the pineapple peel can adsorb the greatest amount of copper. Design/methodology/approach: Sorbent material. The size of the pineapple peel was reduced to 0.250 mm; it was chemically modified with 0.2 M NaOH and 0.2 M CaCl2. Point of zero charge (PZC). Six solutions were prepared with 0.5 g of sorbent in an aqueous medium (with a 3-8 pH range), they were stirred at 225 rpm for 48 h. The derivative method was used to plot the initial pH versus final pH, in order to determine the PZC. Copper adsorption. CuSO4 solutions were prepared in 2, 4, 6, 8 10 mg/L concentrations; 0.1 g of pineapple biomass was added adjusting the pH to 5. The solutions had a contact time of 0 to 24 h. Results: The pineapple peel had a 5.0 point of zero charge (PZC) value, which indicates that pH values higher than the PZC are required to obtain an adsorbent with a negatively charged surface and favor the copper adsorption. A 50% copper removal was obtained in all concentrations after a 1 h contact time. Limitations on study/implications: This research had no limitations. Findings/conclusions: The point of zero charge is a reliable parameter that allows the adsorption process to take place and provides a greater certainty to the metal adsorption process. Meanwhile, pineapple peel can be used as an adsorbent material, consequently reducing its accumulation in open dumps.

Objetivo: Conocer el estado nutrimental del cultivo de piña (Ananas comosus L. Merril). Diseño/metodología/aproximación: El experimento se estableció en el Ejido La Esperanza de Huimanguillo, Tabasco, México. Se tomó una muestra de suelo y del follaje (hoja D) del cultivo de piña, de las cuales se utilizaron tres repeticiones al azar, tomando 15 hojas por repetición. Resultados: Se encontraron concentraciones altas de nitrógeno (N), potasio (K) y magnesio (Mg). Y con relación al fósforo (P), calcio (Ca), cobre (Cu), Zinc (Zn) y boro (B) estuvieron bajos. Los contenidos de fierro (Fe) óptimos y medios para manganeso (Mn) en el tejido vegetal. Limitaciones del estudio/implicaciones: La limitación importante de este estudio es que no se contó con riego. Hallazgos/conclusiones: El suelo es fuertemente ácido y tiene problemas de exceso de fierro y las concentraciones de los macronutrientes en el tejido vegetal y los micronutrientes no están relacionadas directamente con los contenidos de algunos elementos en el suelo. Es necesario hacer un estudio sobre las necesidades de cada elemento en cada una de las etapas fenológicas del cultivo de piña criolla. Aunque el análisis foliar da una visión para el manejo sostenible de la nutrición del cultivo.

Organogallium(III) thioetherbisphenolate complexes of general formulae SmdiolGaMe-THF (1), StdiolGaMe-THF (2), SmdiolGaMe (3) and StdiolGaMe (4) (Smdiol ¼ 2,2 0 -thiobis(4,6-dimethylphenolate); Stdiol ¼ 2,2 0 -thiobis(4,6-diterbuthylphenolate)), were synthesised by methane elimination reactions from GaMe 3 and the diol proligands SmdiolH 2 and StdiolH 2 . The molecular structure of 1 is monomeric and shows the Ga centre adopting a trigonal bipyramidal structure with one of the apical positions occupied by the oxygen atom of a coordinated THF molecule. While the solution spectroscopic data of 4 is in support of a monomeric, probably tetrahedral, species its solid state structure shows a polymeric array built upon intermolecular sulphur-to-gallium interactions resulting in a distorted trigonal bipyramid. The Smdiol derivatives 1 and 3 show modest catalytic activities in Diels-Alder cycloaddition reactions of methacrolein and cyclopentadiene. In addition, StdiolGaH (7) is conveniently synthesized from reaction of StdiolGaCl and t BuLi at room temperature. Compound 7 readily hydrolyses in the presence of trace amounts of water leading to StdiolGa(OH) (8) whose solid state structure was determined.

Objetivo: Este trabajo explora la obtención de celulosa de alta calidad a partir de residuos de piña.   Diseño/metodología/aproximación: Se utilizaron coronas de piña para la obtención de la celulosa utilizando el tratamiento de pre-hidrólisis ácida al 0.5% con ácido sulfúrico combinado con el método de pulpeo Sosa-Antraquinona (SQ) y blanqueo libre de cloro elemental (ECF).  La celulosa obtenida fue caracterizada por las técnicas TAPPI de Espectroscopia Infrarroja por Transformada de Fourier (FTIR), Difracción de Rayos-X (XRD) y Microscopía Electrónica de Barrido con analizador elemental acoplado (SEM-EDX).   Resultados: Se demostró obtener celulosa libre de residuos de las etapas de cloración y blanqueo determinado mediante el análisis elemental SEM (EDX) con un contenido de alfa (α) celulosa de 93%, que exhibe la estructura cristalina típica de celulosa tipo I encontrada comúnmente en las fibras vegetales naturales.   Limitaciones/implicaciones: En el proceso se obtuvo un rendimiento de fibra del 29.3% relativamente bajo. Hallazgos/conclusiones: La obtención de celulosa a partir de los residuos de piña (coronas), se propone como una alternativa de uso debido a su capacidad de refuerzo en los materiales compuestos, así como en la elaboración de biomateriales; mostrando que los residuos agrícolas procedentes de la piña son factibles para la obtención de celulosa.  

Objective: To produce Serrano peppers using a new cultivation technique that mixes the best of hydroponic cultivation and traditional cultivation. Design/methodology/approach: We set up a growing system where the Serrano pepper grew from seedling to its full-fledged state, in a growbag containing sand (as support material), potassium polyacrylate (as water retention material), and a nutrient solution for vegetable gardens, under greenhouse conditions. The humidity level of the growbag is controlled by adding as much water with nutrient solution as needed. This technique has generated 100% harvestable plants (total: 20 plants); more than 90% of the water can be saved in comparison to regular and hydroponic cultivation. Results: Once the harvest began, at least 22.857 kg of Serrano pepper were obtained in 3 m2 of soil in a system with a pyramidal structure in which the 20 plants were placed. If we extrapolated this data, approximately 93,000 kg of Serrano pepper could be harvested from a 1 ha system. Study Limitations/implications: This technique tries to tackle the water access limitations that may exist in some areas of Mexico. However, it does not mitigate the initial costs of a greenhouse system. Nevertheless, this technique can be reused up to 10 times without requiring maintenance. Findings/conclusions: Experience has shown that hydroponic crops are truly profitable, despite their vast water requirements, which is precisely what prevents their global expansion. However, our modification of this method saves more than 90% of the water, using potassium polyacrylate as a retention agent and sand as a support material. Therefore, this technique could be implemented even in places where water is scarce