Application of Orange Peel Waste as Adsorbent for Methylene Blue and Cd2+ Simultaneous Remediation.

Pollution by dyes and heavy metals is one of the main concerns at the environmental level due to their toxicity and inefficient elimination by traditional water treatment. Orange peel (OP) without any treatment was applied to effectively eliminate methylene blue (MB) and cadmium ions (Cd2+) in mono- and multicomponent systems. Although the single adsorption processes for MB and Cd2+ have been investigated, the effects and mechanisms of interactions among multicomponent systems are still unclear. Batch experiments showed that in monocomponent systems, the maximum adsorption capacities were 0.7824 mmol g-1 for MB and 0.2884 mmol g-1 for Cd2+, while in multicomponent systems (Cd2+ and MB), both contaminants competed for the adsorption sites on OP. Particularly, a synergic effect was observed since the adsorption capacity of Cd2+ increased compared to the monocomponent system. Results of desorption and adsorbent reuse confirmed that the adsorbent presents good regeneration performance. The low cost of this material and its capacity for the individual or simultaneous removal of Cd2+ and MB in aqueous solutions makes it a potential adsorbent for polluted water treatment processes.

Experimental and Theoretical Insights on Methylene Blue Removal from Wastewater Using an Adsorbent Obtained from the Residues of the Orange Industry.

Chemical and thermochemical transformations were performed on orange peel to obtain materials that were characterized and further tested to explore their potential as adsorbents for the removal of methylene blue (MB) from aqueous solutions. The results show the high potential of some of these materials for MB adsorption not only due to the surface area of the resulting substrate but also to the chemistry of the corresponding surface functional groups. Fitting of the kinetic as well as the equilibrium experimental data to different models suggests that a variety of interactions are involved in MB adsorption. The overall capacities for these substrates (larger than 192.31 mg g-1) were found to compare well with those reported for activated carbon and other adsorbents of agro-industrial origin. According to these results and complementary with theoretical study using Density Functional Theory (DFT) approximations, it was found that the most important adsorption mechanisms of MB correspond to: (i) electrostatic interactions, (ii) H-bonding, and (iii) π (MB)-π (biochar) interactions. In view of these findings, it can be concluded that adsorbent materials obtained from orange peel, constitute a good alternative for the removal of MB dye from aqueous solutions.

Experimental and computational data set on adsorption of Cr (VI) from water using an activated carbon.

Chromium (Cr) is a widely used metal in metallurgical and chemical industries, whose waste contaminates the surface and groundwater. Cr (VI) is toxic and produces carcinogenic effects owing to its high mobility in water and soil. In this work, computational and experimental studies from the adsorption of Cr(VI) from aqueous solutions on teak wood residues activated with ZnCl2 (AT) are presented. Full interpretation of data can be found in DOI:10.1016/j.jece.2020.103702 [1]. Experimental data were adjusted to Langmuir, Freundlich and Temkin isothermal models and the nonlinear and linear forms of the Pseudo-first and Pseudo-second order kinetic models. Computational data allow to understand the adsorption process of Cr(VI) on carbonaceous materials.

Preparación de carbón activado a partir de residuos de palma de aceite y su aplicación para la remoción de colorantes / Preparation of activated carbon from palm oil wastes and their application for methylene blue removal / Preparação de carvão ativado a partir da resíduos de palmeira de óleo e sua aplicação para a remoção de corantes

Resumen En el presente estudio se muestra la producción de carbón activado a partir de la biomasa residual generada en la producción de palma de aceite, fibra (F) y cáscara (C). Se realizó activación química con ZnCl2 y se evalúo la capacidad de remoción de azul de metileno (AM) para diferentes concentraciones (50, 100 y 150 mg/L). Los resultados mostraron un buen desarrollo de poro por dicho método de activación, con áreas superficiales de 835,3 m2/g para la fibra activada (FA) y 575,1 m2/g para la cáscara activada (CA). Se encontró un buen ajuste de los datos experimentales al modelo cinético de pseudo segundo orden y a las isotermas de Langmuir y Freundlich con capacidades máximas de adsorción de 763,4 y 724,6 mg/g para FA y CA, respectivamente.

Abstract The production of activated carbon from residual biomass generated in the production of oil palm, fiber (F) and shell (C) was studied. The chemical activation was done using ZnCl2 and the adsorption capacity of methylene blue (AM) at different concentrations (50, 100, and 150 mg/L) was evaluated. Results showed a good development of pore with surface areas of 835.3 m2/g for activated fiber (FA) and 575.1 m2/g for activated shell (CA). A good fit of the experimental data with the pseudo second order kinetic model and with Langmuir and Freundlich isotherms models was found. In addition, maximum adsorption capacities of 763.4 and 724.6 mg/g for FA and CA were found, respectively.

Resumo No presente estudo e mostrada a produção de carvão ativado a partir da biomassa residual gerada na produção de fibra de palmeira de óleo (F) e casca (C). A ativação química foi realizada com ZnCl2, foi avaliada a capacidade de remoção do azul de metileno (AM) para diferentes concentrações (de 50, 100 e 150 mg/L). Os resultados mostraram um bom desenvolvimento do poro pelo método de ativação estudado para com áreas de superfície de 835,3 m2/g para a fibras activada (FA) e 575,1 m2/g para a casca activada (CA). Foi encontrado um bom ajuste dos dados experimentais ao modelo da cinética de pseudo segunda ordem e a isotermas de Langmuir e Freundlich com capacidades máximas de adsorção de 763,44 e 724,6 mg/g para a FA e CA, respectivamente.