On the Choice of Batch or Fixed Bed Adsorption Processes for Wastewater Treatment

Abstract

Newly emerged nanomaterials, such as graphene or carbon nanotubes, are of increasingly widespread importance in environmental remediation, especially in their ability to remove undesirable chemicals from hydrological systems. Despite recent advances, the high cost of these materials and the relative inability to regenerate them hinders their use at larger scales. While it is commonly held that adsorption in fixed bed processes is more efficient than in batch processes, the definition of efficiency needs to be examined closely. In this paper, we show that there exists a critical effluent concentration above which batch processes are more efficient than fixed bed processes from this perspective. This work proposes a simple method to choose either batch or fixed bed processes when the goal is to minimize the quantity of adsorbent needed to remove contaminants to below a specified threshold level. It also provides a systematic set of selfconsistency checks on experimental measurements that may be used for comparative studies of these methods.

Recovering Metals from Aqueous Solutions by Biosorption onto Hydrolyzed Olive Cake

“…On the other hand, biosorption in fixed-bed column has the benefit that all fluid exiting the column is free from metals up to a certain time. In batch biosorption, the final metal concentration is greater than zero for all initial metal concentrations tested [44].…”

Towards the Extraction of Radioactive Cesium-137 from Water via Graphene/CNT and Nanostructured Prussian Blue Hybrid Nanocomposites: A Review

“…In certain cases, batch methods appear to be more efficient for contaminant adsorption than fixed bed methods. Such a choice would allow obtaining maximal adsorption with minimal amounts of absorbent, thereby reducing the quantities of radioactive wastes to be treated [99]. Further studies on the toxicity of these carbon-based materials are also required.…”

Nitrogen compounds removal from oil-derived middle distillates by MIL-101(Cr) and its impact on ULSD production by hydrotreating

“…When producing LNSR1LC at LHSV = 1.2 h À1 (~60 wt% N removal) it was estimated that 4.2 mg of N g À1 of MOF were retained, lower amount to that reported at MIL-101(Cr) monolayer saturation when treating SRGO of 131 ppm N (9 mg g À1 , batch system [31]). Performance of an adsorbent depend not only upon its intrinsic equilibrium isotherm relating adsorbed species to bulk liquid concentration but also on the set-up (either batch or fixed-bed) in which the process is carried out [71]. In batch process the adsorbent could get in equilibrium with the remaining concentration in the bulk of fluid phase.…”