Sorption of Remazol Black B dye in alluvial soils of the Capibaribe River Basin, Pernambuco, Brazil

Abstract

Wastewater from textile industries is loaded with synthetic dyes. These effluents are often not adequately treated, affecting the soil and groundwater quality and leading to environmental contamination. The Agreste mesoregion of the state of Pernambuco is home to one of the largest textile centers in Brazil. This work therefore aims to study the behavior of Remazol Black B (RB5) dye in subsurface mediums in this region. The kinetics and isotherm sorption experiments allowed an evaluation of RB5 retention capacity in two layers of alluvial soil of the dry riverbed of the Capibaribe Basin. The maximum sorption rate was 81.81 mg kg-1 and 21.7 mg kg-1 for the loamy sand and sand layers, respectively. The Pseudo-second order kinetic model described more appropriately the sorption kinetics for both soils. The isotherms behavior was nonlinear, and Freundlich model was the most suitable to describe this process for both soils, presenting KF values of 8.6407 L kg-1 for loamy sand and 0.1868 L kg-1 for sand. The isotherm parameters confirm a more significant interaction of RB5 with the loamy sand layer than with the sand layer, indicating lower leaching in the first layer, which is less mobile for RB5 contamination. Furthermore, the different sorption rates for both soils indicate the importance of studying the soil as a heterogeneous profile.

Removal of Remazol Black B dye using bacterial cellulose as an adsorbent

“…In order to know some characteristics about the adsorption kinetics of RBB in cellulose, the experimental data obtained in the kinetic study were evaluated by three kinetic models, namely: the pseudo-first order, pseudo-second order and intraparticle diffusion models (Morris-Weber) using Linear Equations 5, 6 and 7 [25,28,29].…”

“…The adsorption isotherms represent a balance between the concentration of dye in the liquid phase and the amount of dye present in the adsorbent [28,29]. All equilibrium tests were performed in triplicate, the conditions used were: 0.5 g of adsorbent, 150 rpm for 12 h and pH 3.5, in different concentrations of the dye solution (25, 35, 45, 55 and 65 mg L -1 ) and different temperatures (30, 40, 60 and 100 ± 2 ºC).…”

“…All equilibrium tests were performed in triplicate, the conditions used were: 0.5 g of adsorbent, 150 rpm for 12 h and pH 3.5, in different concentrations of the dye solution (25, 35, 45, 55 and 65 mg L -1 ) and different temperatures (30, 40, 60 and 100 ± 2 ºC). The models used were Langmuir and Freundlich according to linearized Equations 8, 9 and 10 [25, [28][29][30][31].…”

“…The thermodynamic characteristics of the process were expressed at different temperatures and concentrations. Through linearized Equations 11, 12 and 13 it is possible to determine the variations of entropy, enthalpy, Gibbs free energy and activation energy of the adsorptive process [25,28,29,32].…”

Sorption of the Direct Black 22 dye in alluvial soil

“…There is also a lack of legislation to regulate their maximum allowable concentration in effluents . Therefore, to enable the development of studies concerning the analysis of groundwater vulnerability and conservation of its quality, it is fundamental to assess retention capacity and mobility of dyes in soils of alluvial deposits (Qu et al, 2008;Dawodu and Akpomie, 2016;Silva Júnior et al, 2019;Alves et al, 2020).…”