Size- and surface charge-controlled layered double hydroxides for efficient algal flocculation

Kim, Tae-Hyun; Hong, In Taek; Oh, Jae‐Min

doi:10.1039/c7en00809k

Cited by 24 publications

(11 citation statements)

References 47 publications

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“…aggregation of negatively charged algal surface. 39 At the exponential phase, excellent cell aggregation efficiency was achieved at PACl dosage of 25 mgAl/L. In the stationary phase, the microalgae floc structure was enhanced by raising PACl dosage.…”

Section: ■ Results and Discussionmentioning

confidence: 90%

“…Figure shows SEM images of flocs coagulated with PACl at 25, 75 and 150 mgAl/L dosage at three growth stages. It was obvious that hydrolyzed products of PACl covered onto the surface of microalgae cells and caused aggregation of negatively charged algal surface . At the exponential phase, excellent cell aggregation efficiency was achieved at PACl dosage of 25 mgAl/L.…”

Section: Resultsmentioning

confidence: 99%

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Flocculation–Dewatering Behavior of Microalgae at Different Growth Stages under Inorganic Polymeric Flocculant Treatment: The Relationships between Algal Organic Matter and Floc Dewaterability

Zhang

Cao

et al. 2018

ACS Sustainable Chem. Eng.

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An algal bloom is a naturally occurring phenomenon in freshwaters due to discharge of wastewater containing nitrogen and phosphate. Coagulation-flocculation was widely used in removal of cyanobacteria and algae organic matter (AOM) from water. Microalgae and AOM differ greatly in physiochemical properties at different growth stages, which are likely to have important effects on their coagulation behavior. In this study, the interacting mechanisms between polymeric aluminum chloride (PACl) and microalgae cells and AOM at the different growth stages were investigated by characterizing morphology and AOM properties of microalgae flocs formed from PACl treatment. The results showed that PACl coagulation exhibited better removal efficiency for the microalgae cells and AOM in exponential and stationary phase than that in decline phase. The protein and humic acid content in loose bound AOM (LB-AOM) were found to be key constituents affecting floc dewatering behavior, and complexation adsorption of hydrolyzed products for proteins and humic substances in LB-AOM was responsible for microalgae floc dewatering improvement. These results provide a novel insight into optimization of flocculation and dewatering of cyanobacteria at different growth stages with PACl treatment.

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Section: ■ Results and Discussionmentioning

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Flocculation–Dewatering Behavior of Microalgae at Different Growth Stages under Inorganic Polymeric Flocculant Treatment: The Relationships between Algal Organic Matter and Floc Dewaterability

Zhang

Cao

et al. 2018

ACS Sustainable Chem. Eng.

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“…As indicated in the open circle curve in Figure 3 A, the average zeta potential of MTX-LDH at neutral pH was 4.61 ± 0.97 mV, showing almost neutral surface charge. Generally, the zeta potential of LDH at neutral pH is very positive, ~+30 mV [ 3 , 55 , 56 , 57 , 58 ], due to the strong positive charge density of LDH layers. However, the zeta potential drops to the neutral value region due to the MTX moieties, which were mostly intercalated into LDH but partially covered the outer surface of LDH layers [ 44 ].…”

Section: Resultsmentioning

confidence: 99%

Physicochemical Properties and Hematocompatibility of Layered Double Hydroxide-Based Anticancer Drug Methotrexate Delivery System

et al. 2020

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A layered double hydroxide (LDH)-based anticancer delivery system was investigated in terms of crystalline phase, particle size, hydrodynamic radius, zeta potential, etc. through in vitro and in vivo study. Size controlled LDH with anticancer drug methotrexate (MTX) incorporation was successfully prepared through step-by-step hydrothermal reaction and ion-exchange reaction. The MTX-LDH was determined to have a neutral surface charge and strong agglomeration in the neutral aqueous condition due to the surface adsorbed MTX; however, the existence of proteins in the media dramatically reduced agglomeration, resulting in the hydrodynamic radius of MTX-LDH being similar to the primary particle size. The protein fluorescence quenching assay exhibited that MTX readily reduced the fluorescence of proteins, suggesting that the interaction between MTX and proteins was strong. On the other hand, MTX-LDH showed much less binding constant to proteins compared with MTX, implying that the protein interaction of MTX was effectively blocked by the LDH carrier. The in vivo hemolysis assay after intravenous injection of MTX-LDH showed neither significant reduction in red blood cell number nor membrane damage. Furthermore, the morphology of red blood cells in a mouse model did not change upon MTX-LDH injection. Scanning electron microscopy showed that the MTX-LDH particles were attached on the blood cells without serious denaturation of cellular morphology, taking advantage of the cell hitchhiking property.

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“…After BSA interactions, the morphology changed to a sand-rose structure; however, the grain diameter of LDO was not seriously altered, suggesting the proteins did not affect the crystallographic features of this clay. While pristine LDO showed a clear grain boundary in the SEM image, the protein-LDO interactant showed a blurred edge, which was often found when an organic moiety covered the LDO or LDH surface [38,39]. The other two clays showed similar pattern to the LDO-protein interactant in terms of surface morphology.…”

Section: Protein-clay Interactant: Surface Morphology and Crystal Strmentioning

confidence: 88%

Physico–Chemical Interaction between Clay Minerals and Albumin Protein according to the Type of Clay

Kim

2019

Minerals

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Clay minerals are widely utilized in pharmaceutical and dermatological sciences as a gastrointestinal medicine or skin remediation agent. In order to verify the feasibility of clays as an injection, pill, or topical agent, it is important to study their interactions with biological components, such as proteins. In this study, we utilized a protein fluorescence quenching assay and circular dichroism spectroscopy to evaluate general aspects of protein denaturation and conformational change, respectively. Three different clays; layered double oxide (LDO), montmorilonite (MMT) and halloysite nanotube (HNT), were treated with albumin and the physico-chemical effect on the protein’s conformation was investigated. MMT was shown to influence the conformational change the most, owing to the large accessible adsorption site. HNT showed meaningful circular dichroism (CD) band collapse as well as fluorescence quenching in the protein, suggesting a potential harmful effect of HNT toward the protein. Among the three tested clays, LDO was determined to affect protein structure the least in terms of three-dimensional conformation and helical structure.

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Size- and surface charge-controlled layered double hydroxides for efficient algal flocculation

Abstract: We evaluated the effects of particle size and surface charge on the algal flocculation activity of layered double hydroxides (LDHs).

Cited by 24 publications

References 47 publications

Flocculation–Dewatering Behavior of Microalgae at Different Growth Stages under Inorganic Polymeric Flocculant Treatment: The Relationships between Algal Organic Matter and Floc Dewaterability

Flocculation–Dewatering Behavior of Microalgae at Different Growth Stages under Inorganic Polymeric Flocculant Treatment: The Relationships between Algal Organic Matter and Floc Dewaterability

Physicochemical Properties and Hematocompatibility of Layered Double Hydroxide-Based Anticancer Drug Methotrexate Delivery System

Physico–Chemical Interaction between Clay Minerals and Albumin Protein according to the Type of Clay

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