The present research shows the results obtained from the biosorption process of Pb, using coffee pulp as a biosorbent in synthetic waters. To do this, the lignin and cellulose content and the percentage of removal of Pb2+ ions was determined; additionally, the sorption’s optimal variables, such as the optimum pH, the point of zero charge (pHpzc), the kinetics and the adsorption isotherm, were determined. A comparison was made with other by-products derived from coffee crops. According to the results obtained in this research, the cellulose percentage was 29.12 ± 0.22% and the lignin percentage was 19.25 ± 0.16% in the coffee pulp, the optimum pH was 2.0 units and the kinetic model, which adjusted to the biosorption’s process, was the pseudo-second order of Ho and McKay, presenting an isotherm of Langmuir’s model and pHpzc of 3.95 units. Lastly, the removal of the pollutant was 86.45%, with a capacity of maximum adsorption of 24.10 mg·g−1 obtained with a particle size of 180 µm, time of contact of 105 min and at 100 RPM. Finally, we express that (a) the coffee pulp can be used as a sustainable alternative for the removal of the pollutant mentioned in synthetic and/or industrial wastewater matrices, to meet goals 3.9 and 6.9 of the Sustainable Development Goals of the 2030 agenda, and (b) the novelty of this research is the use of an agricultural waste of easy acquisition as a sorbent, without chemical modification, since it presented a high percentage of efficiency in the removal of Pb2+ ions. In turn, the challenge of this research is implementing this green technology on a pilot, semi-industrial and/or industrial scale in wastewater treatment systems.

One of the environmental challenges that is currently negatively affecting the ecosystem is the continuous discharge of untreated industrial waste into both water sources and soils. For this reason, one of the objectives of this qualitative study of exploratory-descriptive scope was the review of scientific articles in different databases—Scopus, Web of Science, and Science Direct—published from 2010 to 2021 on the use of fruit peels as a sustainable waste in the removal of heavy metals present in industrial wastewater. For the selection of articles, the authors used the PRISMA guide as a basis, with which 210 publications were found and 93 were compiled. Considering the reported work, a content analysis was carried out using NVivo 12 Plus and VOSviewer 1.6.17 software. The results show that the fruits mentioned in these publications are lemon, banana, mango, tree tomato, pineapple, passion fruit, orange, coconut, avocado, apple, lulo, and tangerine. However, no studies were found with lulo and tree tomato peels. On the other hand, the heavy metals removed with the selected fruit peels were Pb+2, Cr+3, Cr+6, Ni+2, Cd+2, As+5, Cu+2, and Zn+2.

Some of the diverse agro-industrial waste generated in primary or secondary stages have proved to be promising biomaterials for treating aqueous effluents contaminated, in this case, with heavy metals. Therefore, it is necessary to know their optimal operating conditions and the regeneration or reusability of the solid by-product, an aspect related to desorption. Considering the above, this article presents the findings of a preliminary study related to the desorption process of coffee pulp without physicochemical modification (Castilla variety), an agricultural waste used as a sorbent of Cr(III and VI) ions in synthetic wastewater. The desorption efficiency of four eluting agents at defined concentrations (0.10M)—HC1, HNO3, H2SO4, and EDTA—was evaluated in a time interval of 1 to 9 days. Likewise, the proposals for the sorption and/or desorption mechanisms proposed and reported in the literature with respect to the use of biosorbents derived from the coffee crop are presented. With respect to the results, the coffee pulp used in previous studies of the adsorption of chromium species mentioned (optimal conditions in synthetic water of particle size 180 μm, dose 20 g·L−1, agitation 100 RPM, room temperature, time of 90 to 105 min) showed efficiencies in the removal of Cr(III) and Cr(VI) of 93.26% and 74.80%, respectively. Regarding the extracting substances used, H2SO4 0.10 M was the one that presented the highest desorption percentage in both chromic species, with a desorption of 45.75% Cr(VI) and 66.84% Cr(III) in periods of 5 and 9 days, respectively, with agitation of 100 RPM and room temperature. Finally, the dissemination of preliminary results on the desorption of coffee pulp contaminated with chromic species without physicochemical modification is novel in this study, as similar work with this specific material has not yet been reported in the literature. On the other hand, the limitations of the study and future research are related to the evaluation at different concentrations and of other extractor solutions that allow improving the efficiency of desorption of these chemical species in a shorter time from the coffee pulp (with and without modification) as well as the reuse cycles. As a result, the desorption of coffee pulp used as an adsorbent material in real water could help researchers identify the possible interfering factors that affect the process (foreign anions and cations, organic matter, environmental conditions, among others).

Diseño y validación de un sistema de adsorción de cromo hexavalente en efluentes de curtiembre usando cáscara de naranja y salvado de trigo Design and validation of a system for hexavalent chromium adsorption in tannery effluents using orange peel and wheat bran

Los océanos se caracterizan por ser vitales para nuestro planeta Tierra, dado que regulan el clima; en ellos se genera alimentos que sirven de consumo para los seres humanos; por medio del movimiento de las olas se produce el intercambio gaseoso que permite el aumento de las concentraciones de oxígeno; y, a su vez, son el lugar que ocupan varias especies animales y vegetales. Desafortunadamente, día a día, por las diferentes actividades humanas a nivel mundial, se han visto afectados en un 75 %, por contaminación, debido a que, la mayoría de los ríos que desembocan en ellos, los contaminan, en un 90 % aproximadamente.Por esta razón, evitar su deterioro y resaltar la importancia de este recurso, se encuentra contemplado en el Objetivo del Desarrollo Sostenible 14 (Naciones Unidas, 2018); adicionalmente, las diversas actividades de pesca artesanal los han ido deteriorando progresivamente. Dado lo anterior, se busca socializar los resultados de una revisión bibliográfica llevada a cabo en el periodo 2000 - 2021 dentro de las bases de datos Scopus y Web of Science (WoS) acerca del tema: basura marina en Colombia. La investigación fue de corte cualitativo, de alcance exploratorio-descriptivo, cuyo fin fue analizar la tendencia en cuanto a lo mencionado en el contexto colombiano, así como los lugares y situaciones investigadas. Adicionalmente, los aportes, desafíos, oportunidades y posibles propuestas para la reducción y/o mitigación de la situación abordada por los autores en sus manuscritos. Con relación a los resultados y análisis, se revisó y seleccionó 21 productos investigativos, mostrando la mayor producción en el año 2020. Asimismo, se da cuenta de los desafíos, oportunidades, vacíos en términos de la formulación de políticas ambientales, gestión y manejo de residuos sólidos, como, por ejemplo, los plásticos en las playas del caribe colombiano, la protección de las áreas marinas y, bases de datos sobre información de la salud acuática. Finalmente, se muestra los resultados de investigaciones en algunas zonas intervenidas en Colombia.