Flocculation morphology: effect of particulate shape and coagulant species on flocculation

2006 ◽  
Vol 53 (7) ◽  
pp. 9-16 ◽  
Author(s):  
Jiang Zhanpeng ◽  
Guan Yuntao
Keyword(s):  
Natural Waters ◽  
Colloidal Particles ◽  
Morphological Characteristics ◽  
Process Efficiency ◽  
Traditional Theory ◽  
Nonspherical Particles ◽  
Morphology Model ◽  
Morphology Effect ◽  
Near Future ◽  
Flocculation Process

Flocculation morphology is a new concept that investigates the morphological characteristics of colloidal particles and coagulants in water during the flocculation process, and the influence that these characteristics have on flocculation process efficiency. This paper is a summary of advances in research on this topic over several years. Morphological characteristics of colloids in natural waters and different kinds of hydrolysed coagulants are investigated, and their effect on colloid stability, flocculation kinetics and efficiency is analysed. It is confirmed that the traditional theory has some deviations in coagulation of nonspherical particles, and these deviations are revised by the flocculation morphology model. Flocculation morphology can not only promote research about flocculation theory, but also instruct the production, application and flocculation control. It can be foreseen that more progress will be made in research and application of flocculation morphology in the near future.

scholarly journals Heteroagglomeration of nanosilver with colloidal SiO2 and clay

2017 ◽  
Vol 14 (1) ◽  
pp. 1 ◽  
Author(s):  
Sébastien Maillette ◽  
Caroline Peyrot ◽  
Tapas Purkait ◽  
Muhammad Iqbal ◽  
Jonathan G. C. Veinot ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Polyacrylic Acid ◽  
Natural Waters ◽  
Colloidal Particles ◽  
Colloidal Stability ◽  
Analytical Techniques ◽  
Dark Field ◽  
Correlation Spectroscopy ◽  
Colloidal Clay ◽  
High Concentrations

Environmental contextThe fate of nanomaterials in the environment is related to their colloidal stability. Although numerous studies have examined their homoagglomeration, their low concentration and the presence of high concentrations of natural particles implies that heteroagglomeration rather than homoagglomeration is likely to occur under natural conditions. In this paper, two state-of-the art analytical techniques were used to identify the conditions under which nanosilver was most likely to form heteroagglomerates in natural waters. AbstractThe environmental risk of nanomaterials will depend on their persistence, mobility, toxicity and bioaccumulation. Each of these parameters is related to their fate (especially dissolution, agglomeration). The goal of this paper was to understand the heteroagglomeration of silver nanoparticles in natural waters. Two small silver nanoparticles (nAg, ~3nm; polyacrylic acid- and citrate-stabilised) were covalently labelled with a fluorescent dye and then mixed with colloidal silicon oxides (SiO2, ~18.5nm) or clays (~550nm SWy-2 montmorillonite). Homo- and heteroagglomeration of the nAg were first studied in controlled synthetic waters that were representative of natural fresh waters (50μg Ag L–1; pH 7.0; ionic strength 10–7 to 10–1 M Ca) by following the sizes of the nAg by fluorescence correlation spectroscopy. The polyacrylic acid-coated nanosilver was extremely stable under all conditions, including in the presence of other colloids and at high ionic strengths. However, the citrate-coated nanosilver formed heteroaggregates in presence of both colloidal SiO2 and clay particles. Nanoparticle surface properties appeared to play a key role in controlling the physicochemical stability of the nAg. For example, the polyacrylic acid stabilized nAg-remained extremely stable in the water column, even under conditions for which surrounding colloidal particles were agglomerating. Finally, enhanced dark-field microscopy was then used to further characterise the heteroagglomeration of a citrate-coated nAg with suspensions of colloidal clay, colloidal SiO2 or natural (river) water.

scholarly journals Subseafloor basalts as fungal habitats

2012 ◽  
Vol 9 (2) ◽  
pp. 2277-2306 ◽  
Author(s):  
M. Ivarsson
Keyword(s):  
Morphological Characteristics ◽  
Microbial Life ◽  
Ocean Drilling ◽  
Potential Habitat ◽  
The Pacific ◽  
Fungal Hyphae ◽  
The Pacific Ocean ◽  
Life On Earth ◽  
Near Future ◽  
Deep Subseafloor

Abstract. The oceanic crust is believed to host the largest potential habitat for microbial life on Earth, yet, next to nothing is known about this deep, concealed biosphere. Here fossilised fungal colonies in subseafloor basalts are reported from three different seamounts in the Pacific Ocean. The fungal colonies consist of various characteristic structures interpreted as fungal hyphae, fruit bodies and spores. The fungal hyphae are well preserved with morphological characteristics such as hyphal walls, septa, thallic conidiogenesis, and hyphal tips with hyphal vesicles within. The fruit bodies consist of large (~50–200 μm in diameter) body-like structures with a defined outer membrane and an interior filled with calcite. The fruit bodies have at some stage been emptied of their contents of spores and filled by carbonate forming fluids. A few fruit bodies not filled by calcite and with spores still within support this interpretation. Spore-like structures (ranging from a few μm:s to ∼20 μm in diameter) are also observed outside of the fruit bodies and in some cases concentrated to openings in the membrane of the fruit bodies. The hyphae, fruit bodies and spores are all closely associated with a crust lining the vein walls that probably represent a mineralized biofilm. The results support a fungal presence in deep subseafloor basalts and indicate that such habitats were vital between ∼81 and 48 Ma, and probably still is. It is suggested that near future ocean drilling programs prioritize sampling of live species to better understand this concealed biosphere.

scholarly journals Development of an electrocoagulation equipment for wall paint wastewater treatment

2020 ◽  
Vol 22 (2) ◽  
pp. 1-10
Author(s):  
Gonzalo Forero-Forero ◽  
Rocío Hernández-Lara ◽  
Omar Rojas
Keyword(s):  
Waste Water ◽  
Wastewater Treatment ◽  
Colloidal Particles ◽  
Current Source ◽  
Oxygen Demand ◽  
Chemical Compounds ◽  
Process Efficiency ◽  
Before And After ◽  
Electrocoagulation Process ◽  
A Current

This article describes the tests carried out to evaluate the process efficiency water treatment by electrocoagulation in construction paint waste water. Electrocoagulation process consists of an electrolytic reactor, equipped with a current source and electrodes responsible for providing the destabilizing ions of colloidal particles, so that they replace the function of the chemical compounds used in conventional wastewater treatment. For the experimental design, we use drinking water and wall paint, in order to treat the solution by electrocoagulation in a treatment scale plant to compare the results before and after treatment, the variables to be measured are: dissolved oxygen (DO); turbidity; pH; conductivity; temperature; chemical oxygen demand (COD).After review the efficiencies obtained, we proceed to the development of an equipment treatment that can treat the waste water from washing brushes and rollers to be reused again in the washing, avoiding contamination caused by washing tools after painting surfaces in construction processes.

Research on design parameters of rapid mixing in turbulence

2006 ◽  
Vol 6 (4) ◽  
pp. 135-143 ◽  
Author(s):  
D. Wu ◽  
F. Tan ◽  
Y. Ma ◽  
F. Shi
Keyword(s):  
Colloidal Particles ◽  
Operating Cost ◽  
Design Parameters ◽  
Mixing Efficiency ◽  
Physical Parameters ◽  
Traditional Theory ◽  
Rapid Mixing ◽  
Turbid Waters ◽  
Coagulant Dosage ◽  
First Time

Turbid waters, containing suspended and colloidal particles, are normally treated by coagulation–flocculation followed by clarification. The process usually consists of the rapid dispersal of a coagulant into the raw water followed by an intense agitation commonly defined as rapid mixing. Mixing is influenced by chemical and physical parameters, and the result of the whole treatment depends on these steps. It is concluded that the proper process of mixing is able to not only improve outlet water quality, but also helps reduce energy dissipation, coagulant dosage and operating cost. It is evidenced, however, that the traditional theory of mixing should be modified. Based on hydrodynamics analysis and experimental results, a mixing model for turbulent flow is presented for the first time. The speed of macroscopic mixing is governed by turbulent diffusion, and the speed of microcosmic mixing is governed by molecule diffusion. The mixing process is dominated by macroscopic mixing. The Euler number Eu can be used as the design parameter that determines the mixing efficiency.

scholarly journals Single-cell RNA-seq analysis reveals penaeid shrimp hemocyte subpopulations and cell differentiation process

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Keiichiro Koiwai ◽  
Takashi Koyama ◽  
Soichiro Tsuda ◽  
Atsushi Toyoda ◽  
Kiyoshi Kikuchi ◽  
...  
Keyword(s):  
Immune System ◽  
Single Cell ◽  
Morphological Characteristics ◽  
Penaeid Shrimp ◽  
Rna Seq ◽  
Single Cell Rna Sequencing ◽  
Immune Related Genes ◽  
Near Future ◽  
Differentiation Pathways

Crustacean aquaculture is expected to be a major source of fishery commodities in the near future. Hemocytes are key players of the immune system in shrimps; however, their classification, maturation, and differentiation are still under debate. To date, only discrete and inconsistent information on the classification of shrimp hemocytes has been reported, showing that the morphological characteristics are not sufficient to resolve their actual roles. Our present study using single-cell RNA sequencing, revealed six types of hemocytes of Marsupenaeus japonicus based on their transcriptional profiles. We identified markers of each subpopulation and predicted the differentiation pathways involved in their maturation. We also predicted cell growth factors that might play crucial roles in hemocyte differentiation. Different immune roles among these subpopulations were suggested from the analysis of differentially expressed immune-related genes. These results provide a unified classification of shrimp hemocytes, which improves the understanding of its immune system.

Experimental research of photodegradation processes of organic compounds of natural waters

2018 ◽  
pp. 75-80
Author(s):  
O. Yu. Drozdova ◽  
N. A. Anohina ◽  
V. V. Demin ◽  
S. A. Lapitskiy
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Carboxylic Acids ◽  
Organic Compounds ◽  
Experimental Research ◽  
Natural Waters ◽  
Colloidal Particles ◽  
Total Content ◽  
Field Conditions ◽  
Aromatic Carboxylic Acids

In order to study the effect of sunlight on the composition and properties of dissolved organic matter and metal forms in natural waters, the process of photodegradation of organo-mineral complexes in field conditions with samples of soil and swamp waters was studied. Total content of certain aliphatic and aromatic carboxylic acids increased in the studied samples after irradiation. Photodegradation of organic matter of the natural waters that are rich in iron is accompanied by formation of colloidal particles (Fe hydroxides). The amount of negatively-charged complexes of Ni, Cu, Zn and Cd increases during the insolation in swamp waters and decreases in soil waters.

Fractal Theory’s Investigation in Pneumatic Flocculation Process

2011 ◽  
Vol 383-390 ◽  
pp. 6427-6430
Author(s):  
Long Wang ◽  
Yan Li ◽  
Qin Qin Zhang ◽  
Guang Lei Xue
Keyword(s):  
Fractal Dimension ◽  
Morphological Characteristics ◽  
Floc Characteristics ◽  
Flocculation Process

Coagulation-sedimentation test at different inflatable combinations, and using microscope to observe the morphological characteristics of flocs. This paper also measured the flocs’ fractal dimension. And analyzed the relationships between fractal dimension and floc characteristics, Coagulation effect

Elimination of man-made radionuclides from natural waters by applying a standard coagulation-flocculation process

2004 ◽  
Vol 260 (2) ◽  
pp. 321-326 ◽  
Author(s):  
A. Baeza ◽  
M. Fernández ◽  
M. Herranz ◽  
F. Legarda ◽  
C. Miró ◽  
...  
Keyword(s):  
Natural Waters ◽  
Flocculation Process

scholarly journals Mathematical modelling and analysis of the flocculation process in low retention time hydraulic flocculators

Water SA ◽  
2019 ◽  
Vol 45 (1 January) ◽  
Author(s):  
Danieli Soares De Oliveira ◽  
Clainer Bravin Donadel
Keyword(s):  
Retention Time ◽  
Rational Design ◽  
Physical Modelling ◽  
Process Efficiency ◽  
Particle Interactions ◽  
Helically Coiled Tube ◽  
Proposed Model ◽  
Recycling Systems ◽  
Flocculation Process ◽  
Flocculation Time

This article aims to advance the understanding of particle interactions in low retention time flocculators and proposes a new flocculation model that appropriately considers the influence of retention time in flocculation processes. This consideration is important for units with flocculation time lower than 1 min, as seen in helically coiled tube flocculators (HCTFs), whose retention time is significantly lower than conventional flocculation units (about 30 min). With this, it was possible to obtain a more adherent model, reducing deviations between results obtained by physical modelling (using HCTFs, 48 tests) and those obtained with the proposed model, when compared with results obtained using the flocculation models commonly used for this purpose. The decreasing-rising behaviour presented by experimental data for process efficiency versus retention time, not verified in the benchmark models, was satisfactorily addressed by the proposed model. Furthermore, maximum and average absolute percentage deviations obtained using the model proposed in this study were less than or equal to the results obtained with the benchmark models and less for experimental uncertainty (10%). The results obtained indicate that this model can be a useful tool to support the rational design of low retention time units, including applications for the water industry and water recycling systems.

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