Research on the Batch and Fixed-Bed Column Performance of Red Mud Adsorbents for Lead Removal

Abstract

Abstract:The removal of lead from water by red mud using batch and fixed-bed column adsorption techniques was investigated. In a batch study, experiments indicated that the time to attain equilibrium was 2h. The experimental data fitted well to a Langmuir adsorption isotherm and the adsorption capacity was 18.87 mg/g. Fixed-bed column experiments were carried out for different influent lead concentrations, bed depths, and various flow rates. The breakthrough time and exhaustion time decreased with increasing flow rate, decreasing bed depth and increasing influent lead concentration. The bed depth service time model and the Thomas model were applied to the experimental results. Both model predictions were in good agreement with the experimental data for all the process parameters studied, indicating that the models were suitable for red mud fix-bed column design.

Experimental Design and Breakthrough Curve Modeling of Fixed-Bed Columns Utilizing a Novel 3D Coconut-Based Polyurethane-Activated Carbon Composite Adsorbent for Lead Sequestration

“…These trends are consistent with findings from prior research [55,56], indicating that surface mass transfer plays a significant function in the kinetics of the overall system, particularly throughout the preliminary phase of column adsorption [57]. Although the Bohart-Adams model is widely utilized and valuable for conducting and analyzing adsorption-column experiments, it is crucial to acknowledge that its applicability is limited to certain experimental conditions [41,43]. The model's correlation coefficient falling below 0.96 indicates that it is not sufficient for fully capturing the adsorption behavior of the column.…”

“…The experimental results show that elevating the bed height from 50 mm to 150 mm resulted in an extended time for the bed to achieve saturation. This observation implies a correlation between the breakthrough curve and the bed height, indicating an expansion in the zones of mass transfer [41]. Additionally, Figure 6 demonstrates that reducing the bed height resulted in a more rapid saturation.…”

Polysaccharides as Protective Agents against Heavy Metal Toxicity

“…Polysaccharides possess distinctive chemical bonds and functional groups that enable their effective elimination of heavy metals. Multiple investigations have additionally verified that polysaccharides have the capacity to alleviate heavy metal toxicity [ 17 ]. Current research attributes the adsorption mechanism of polysaccharides for heavy metals to the mix of chemical groups (such as hydroxyl, carbonyl, sulfhydryl, etc.)…”

Methylene Blue and Iron (II) Adsorption onto Raphia Hookeri Seed: A Comparative Equilibrium Isotherm Study

“…Resultant values of various isotherm parameters obtained from their corresponding correlations provide vital information on the adsorption mechanisms, surface properties and the feasibility of the adsorption system. These isotherm equations can be used for certain purposes, such as the design of columns/systems that would perform effectively adsorption [4,5].…”