Magnetic seeding coagulation: Effect of Al species and magnetic particles on coagulation efficiency, residual Al, and floc properties

Abstract

Compositing MPs to AlCl 3 improved primary cluster size and their aggregation. MPs-Al 13 -DOM clusters facilitated DOC removal and residual Al reduction. Significant interaction for turbidity removal was observed between MPs and Al 30 . Interactions between Al species and MPs guide the application of an effective MSC process.

Characterization of particles and their relation with residual aluminum in water treated with pulsating floc blanket clarifiers and conventional clariflocculators using PACl

“…CC (C 1-5 ) and PFBC (P 1-5 ), for different influent conditions, the resulting fractal dimensions with their standard error (SE), coefficient of determination (R 2 ), mean characteristic length (l ), population (N) and settling velocity (W s ) ratio are mentioned in Table 2. The range of values of D 2 and D 3 for PACl flocs is in good agreement with the respective values reported for flocs formed after unit processes of coagulation-flocculation (Chakraborti et al 2007;Wang et al 2016;Lv et al 2021). Also, for all influent conditions, the fractal dimension data was highly correlated, as indicated by R 2 values and with the reasonably large analysed population (N .…”

“…The destabilization power of aluminum-based coagulants (due to trivalent Al 3þ ions) is multiple times more than that of coagulants which furnish monovalent/divalent ions and given their cost effectiveness, are widely used in water treatment facilities. Amongst these, poly aluminum chloride (PACl) has been popularly used in treatment of low turbidity water owing to speciation, stability, transformation and mechanistic advantages primarily related to relatively abundant polymeric aluminum species like 'Keggin' structured cation [Al 13 O 4 (OH)] n 7þ (Wang et al 2004;Casey 2006;Lv et al 2021). However, optimal utilization of such coagulants is crucial to address the serious issue of residual aluminum in treated water which has been implicated as a potential neuro-toxin (Edzwald 2020;Exley & Clarkson 2020).…”

“…Coagulation-flocculation behavior exhibited under the two fundamentally different treatment processes influences inter-related parameters like particle aggregation and destabilization; surface adsorption and coverage; floc characteristics; microfloc formation and kinetics; and finally, the performance of subsequent unit operations. The ensuing floc structure, size, fractal dimensions, density and morphology not only play an important role in determining settleability and hence removal efficiency of flocs, but also give key indications about the efficiency of water treatment often measured in terms of parameters like turbidity and concentration of residuals (Yu et al 2011;Wang et al 2016;Tsai et al 2020;Lv et al 2021). Moreover, since particulate aluminum species can play an important role in elevating total residual aluminum levels (Driscoll & Letterman 1995), it is of interest to evaluate the role a floc blanket may have on the properties of fine colloidal suspensions.…”

Magnetic nanoadsorbents for micropollutant removal in real water treatment: a review

“…The design of the magnetic separator system will have to be properly tuned for the following parameters on a case-to-case basis as well: its optimal geometry in relation to aqueous stream flow patterns (Kheshti et al 2019b ), potential flocculation and coagulation behaviors (Lv et al 2019 , 2021 ; Sun et al 2021 ), flow paths (Kakihara et al 2004 ; Tang et al 2014 ) and effects of turbulences and variable fluid shear forces; concentrations and mass loading of magnetic nanoadsorbents (Powell et al 2020 ); the magnetic field strength distributions, flow velocity profiles and liquid streamlines being developed during the magnetic separation; the exposure intensity; effects of any residual magnetization arising from presence of mechanical components (Powell et al 2020 ); colloidal stability and magnetic separability (Hutchins and Downey 2020 ); and residence time distributions with or without effluent recirculation.…”

Removal of Pb2+ from Wastewater By γ‐Fe2O3@SHFA Based on Alkali‐Modified Fly Ash: Performance and Mechanism

“…The magnetic coagulation process is to add magnetic powder (such as Fe 3 O 4 ) in the coagulant, so that the colloidal particles of pollutants and magnetic species form larger flocculation, thus accelerate the sedimentation. [17][18][19][20] The magnetic composites by modifying albeit with hydrochloric acid and mixing it with ferric tetroxide, and achieved 95% removal of Cr(VI) within 10 min. [21] Compared with traditional coagulation technology, a magnetic coagulant makes the flocs formed after coagulation magnetic, which is beneficial to floc separation and improves the efficiency of solid-liquid separation.…”