Concentrating Dilute Sludge Wastes with High-Gradient Magnetic Separation:  Breakthrough Experiments and Performance

Abstract

High-gradient magnetic separation (HGMS) was successfully investigated for the concentration of dilute sludge wastes using a 0.3-T bench-scale system. Breakthrough curves for four different sludges containing a blend of paramagnetic metal hydroxides and oxides were measured at different feed velocities (0.0367-0.2754 cm s -1 ) and suspended insoluble solids feed concentrations (2.5-10.5 g L -1 ). With the aid of a dynamic model fitted to each of the breakthrough curves, the best bed utilizations of the HGMS unit and the highest enrichments of the feed were, respectively, on the order of 77% and 14 for the runs with lower feed velocities and concentrations. These results also corresponded to the HGMS unit producing on the order of 20 bed volumes of effluent free of suspended insoluble solids prior to breakthrough. Overall, the performance of the HGMS unit for this type of process was considered to be quite good, given the broad range of particle sizes, magnetic susceptibilities, and molecular species in each sludge waste. These results suggest that HGMS can be used as an effective and alternative treatment method for the concentration of a variety of dilute waste streams containing suspended solids of a diverse nature.

Interaction of Chromate on Surfactant Modified Montmorillonite: Breakthrough Curve Study in Fixed Bed Columns

“…Adding together, the van der Waals packing radii for a 3-methylammonium head group yields a diameter of 0.694 nm with a fully extended chain length of 3.5 nm. 8 To examine whether the surfactant molecules were intercalated, the treated column bed was thoroughly washed and subjected to X-ray diffraction. The XRD pattern shows no significant variation in the interlayer distances of surfactant modified and chromium adsorbed clays (Figure 4).…”

“…HDTMA comprises a tail group of a 16-carbon chain attached to a head group of a 3-methyl quaternary amine with a 1+ charge. Adding together, the van der Waals packing radii for a 3-methylammonium head group yields a diameter of 0.694 nm with a fully extended chain length of 3.5 nm . To examine whether the surfactant molecules were intercalated, the treated column bed was thoroughly washed and subjected to X-ray diffraction.…”

“…6 Surfactant immobilized interlayer species (SIIS) bound to clay can facilitate the admission of metal ion species into the interlayer irrespective of their sizes. 7 According to Armin et al, 8 breakthrough techniques offer advantages over other more traditional techniques such as batch extraction, ion exchange, and chemical reduction because of their (a) sustainable process control and regeneration, (b) cheap technology due to cheap auxiliary agents and low cost of adsorption agents, (c) high treatment efficiency due to efficient process control, (d) compact system due to quick adsorption and desorption, and (e) suitability for both small-and largescale applications. The objective of this paper is to study the shapes of breakthrough curves with respect to the interaction of chromate in a fixed bed column of montmorillonite clay treated with surfactants known to swell smectite clays.…”

Application of High-Gradient Magnetic Separation for the Recovery of Super-Paramagnetic Polymer Adsorbent Used in Adsorption and Desorption Processes

“…Firstly, a microscopic level focuses on the forces responsible for the attraction and capture of a single particle on the magnetized wire [35,36]. The other approach uses a macroscopic view, describing the whole filter based on the breakthrough behavior of the filter [37,38].…”