scholarly journals The Promotion/Inhibition of the Seepage Transport of Copper Ions by Suspension-Colloidal Particles with Wide Size Gradation

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Qingke Nie ◽  
Huawei Li ◽  
Haipeng Yang ◽  
Tengfei Ni ◽  
Sichen Jiang
Keyword(s):  
Heavy Metal ◽  
Particle Size ◽  
Large Scale ◽  
Colloidal Particles ◽  
Copper Ions ◽  
Small Scale ◽  
Average Particle ◽  
Promoting Effect ◽  
Transport Distance ◽  
Retarding Effect

Sand column tests were conducted to investigate the seepage transport of silicon powders (SPs) with two wide particle size ranges (30-2000 nm and 2-70 μm), including the cotransport of SPs and copper ions. The results show that the graded large-scale SP has an obvious inhibiting influence on the transport of copper ions. In contrast, in the presence of the graded small-scale SP, the concentration of copper ions in the effluent tends to increase; i.e., there appears to be a promoting effect. However, after a long transport distance, the presence of SPs, regardless of particle size, has an overall retarding effect on heavy metal pollutants (e.g., copper ions). The promoting effect of the increase in seepage velocity on the concentration of copper ions in the effluent is greater with the graded large-scale SPs than with the graded small-scale SPs. In terms of the microstructural characteristics by metallographic microscopy, the average particle size of the deposited graded small-scale SPs is almost constant at different transport distances, while that of the deposited graded large-scale SPs tend to decrease significantly with increasing transport distance; i.e., notable bed filtration is exhibited in the latter case. This physical mechanism also determines the sequence and rate of the retarding effect of SPs on heavy metal ions under seepage flow.

scholarly journals Pharmaceutical Particles Design by Membrane Emulsification: Preparation Methods and Applications in Drug Delivery

2017 ◽  
Vol 23 (2) ◽  
pp. 302-318 ◽  
Author(s):  
Emma Piacentini ◽  
Marijana Dragosavac ◽  
Lidietta Giorno
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Rational Design ◽  
Large Scale ◽  
Drug Loading ◽  
Small Scale ◽  
Scale Production ◽  
Membrane Emulsification ◽  
Preparation Methods ◽  
Promising Tool

Nowadays, the rational design of particles is an important issue in the development of pharmaceutical medicaments. Advances in manufacturing methods are required to design new pharmaceutical particles with target properties in terms of particle size, particle size distribution, structure and functional activity. Membrane emulsification is emerging as a promising tool for the production of emulsions and solidified particles with tailored properties in many fields. In this review, the current use of membrane emulsification in the production of pharmaceutical particles is highlighted. Membrane emulsification devices designed for small-scale testing as well as membrane-based methods suitable for large-scale production are discussed. A special emphasis is put on the important factors that contribute to the encapsulation efficiency and drug loading. The most recent studies about the utilization of the membrane emulsification for preparing particles as drug delivery systems for anticancer, proteins/peptide, lipophilic and hydrophilic bioactive drugs are reviewed.

scholarly journals Micromechanical study of potential scale effects in small-scale modelling of sinker tree roots

2021 ◽  
Author(s):  
Xingyu Zhang ◽  
◽  
Matteo Ciantia ◽  
Jonathan Knappett ◽  
Anthony Leung ◽  
...  
Keyword(s):  
Particle Size ◽  
Large Scale ◽  
Scale Effects ◽  
Distinct Element ◽  
Scaling Law ◽  
Scale Model ◽  
Small Scale ◽  
Tree Roots ◽  
Scale Modelling ◽  
Element Method

When testing an 1:N geotechnical structure in the centrifuge, it is desirable to choose a large scale factor (N) that can fit the small-scale model in a model container and avoid unwanted boundary effects, however, this in turn may cause scale effects when the structure is overscaled. This is more significant when it comes to small-scale modelling of sinker root-soil interaction, where root-particle size ratio is much lower. In this study the Distinct Element Method (DEM) is used to investigate this problem. The sinker root of a model root system under axial loading was analysed, with both upward and downward behaviour compared with the Finite Element Method (FEM), where the soil is modelled as a continuum in which case particle-size effects are not taken into consideration. Based on the scaling law, with the same prototype scale and particle size distribution, different scale factors/g-levels were applied to quantify effects of the ratio of root diameter (𝑑𝑟) to mean particle size (𝐷50) on the root rootsoil interaction.

scholarly journals Preparation and Investigation of Intelligent Polymeric Nanocapsule for Enhanced Oil Recovery

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1093 ◽  
Author(s):  
Fang Shi ◽  
Jingchun Wu ◽  
Bo Zhao
Keyword(s):  
Particle Size ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Colloidal Particles ◽  
Critical Concentration ◽  
Average Particle Size ◽  
Average Particle ◽  
Assembly Method ◽  
Recovery Capacity ◽  
Wide Range

Micro-/nanomotors colloidal particles have attracted increasing interest as composite surfactants, owing to the combined advantages of both Janus solid surfactants and micro-/nanomotors. Here we put micro-/nanomotors colloidal particles into hollow polymeric micro-encapsulates. An intelligent polymeric nanocapsule was prepared for enhanced oil recovery by the self-assembly method. The particle size range of the polymeric capsule can be controlled between 20 to 1000 nm by adjusting the cross-linking thickness of the capsule’s outer membrane. The average particle size of polymeric capsules prepared in the study was 300 nm. The structure and properties of the Intelligent polymeric nanocapsule was characterized by a wide range of technics such as Fourier transform infrared spectroscopy, scanning electron microscopy by laser diffraction, fluorescence microscopy, pendant drop tensiometer, laser particle size instrument, and interface tension analyzer. It was found that the intelligent polymeric nanocapsule exhibited significant interfacial activity at the oil-water interface. When the Janus particles’ concentration reached saturation concentration, the adsorption of the amphiphilic nanoparticles at the interface was saturated, and the equilibrium surface tension dropped to around 31 mN/m. When the particles’ concentration reached a critical concentration of aggregation, the Gibbs stability criterion was fulfilled. The intelligent polymeric nanocapsule system has a better plugging and enhanced oil recovery capacity. The results obtained provide fundamental insights into the understanding of the assembly behavior and emulsifying properties of the intelligent polymeric nanocapsule, and further demonstrate the future potential of the intelligent polymeric nanocapsule used as colloid surfactants for enhanced oil recovery applications.

scholarly journals Effective Removal of Cr(VI) from Wastewater Using Biochar Derived from Walnut Shell

2021 ◽  
Vol 18 (18) ◽  
pp. 9670
Author(s):  
Tanzeela Kokab ◽  
Hafiza Sumbal Ashraf ◽  
Muhammad Bilal Shakoor ◽  
Asim Jilani ◽  
Sajid Rashid Ahmad ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Large Scale ◽  
Walnut Shell ◽  
Small Scale ◽  
Toxic Heavy Metal ◽  
Modern Age ◽  
Effective Removal ◽  
Scale Levels ◽  
High Concentrations

Heavy metals are the major concern of the modern age. Among the heavy metals, chromium (Cr(VI)) is regarded as a highly toxic heavy metal released largely from leather tanning operations. To remove such high concentrations of Cr(VI), an advanced method is required urgently. Thus, biosorption using biochar, which is an organic material produced from various sources such as walnut shell, can be applied successfully for Cr(VI) abatement. The major objectives of this experiment were the remediation of the Cr(VI) heavy metal using walnut shell biochar and checking of the effect of pH, biochar dosage, Cr level, and shaking time. Remediation of Cr(VI) using walnut shell biochar was proved to be effective and removed the maximum concentration of Cr(VI) up to 93% at pH 5.5, 2 h agitation time, and the biochar amount of 1.1 g L−1 from an aqueous solution. Equilibrium modeling demonstrated that the chemisorption process was involved in adsorption of Cr(VI). The surface of the biochar was porous and provided numerous sites for Cr(VI) attachment, which was also confirmed by the presence of Cr(VI) onto the biochar after adsorption. Hence, the use of walnut shell biochar was highly effective as a sorbent, which could conveniently be applied to small-scale as well as large-scale levels.

scholarly journals Effect of Particle Size on the Hydraulic Characteristics of Mechanically and Biologically Treated Waste

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhenying Zhang ◽  
Xiufeng Pan ◽  
Jiahe Zhang ◽  
Hui Xu
Keyword(s):  
Particle Size ◽  
Large Scale ◽  
Void Ratio ◽  
Average Particle Size ◽  
Dry Mass ◽  
Dry Density ◽  
Average Particle ◽  
Vertical Permeability ◽  
The Difference ◽  
Reduce Emissions

Mechanical biological treatment (MBT) is a waste processing technology that helps conserve resources and reduce emissions harmful to the environment. The treatment of municipal solid waste (MSW) using MBT is a hot topic in environmental geotechnical engineering. Permeability tests were carried out on MBT waste using a compression and permeability combined apparatus and a large-scale vertical permeability apparatus taking the influence of particle size into consideration. The permeability of samples with smaller particle sizes was found to be lower for the same pressure and dry mass (%) of component. The best-fit line between the logarithmic permeability and variables such as the dry density was linear. As the dry density increased or the void ratio decreased, the permeability of samples with smaller particles decreased more. The logarithmic permeability increased with the increase in the average particle size and void ratio. The permeabilities of MBT waste corresponding to particle size ranges of 0–10, 0–20, and 0–40 mm were 10−10–10−5, 10−8–10−4, and 10−5–10−3 m/s, respectively. The difference between MBT waste and MSW was analyzed in terms of their permeability. The results of MBT waste were compared with those reported in previous studies to provide reference for the permeability analysis of MBT landfills.

scholarly journals High-Yield Production of Nano-Lateral Size Graphene Oxide by High-Power Ultrasonication

2021 ◽  
Author(s):  
Licínia Timochenco ◽  
Raquel Costa-Almeida ◽  
Diana Bogas ◽  
Filipa A.L.S. Silva ◽  
Joana Silva ◽  
...  
Keyword(s):  
Particle Size ◽  
High Power ◽  
Large Scale ◽  
Average Particle Size ◽  
High Yield ◽  
Average Particle ◽  
Scale Production ◽  
Lateral Size ◽  
Aqueous Dispersions ◽  
The Impact

Nanographene oxide (GOn) constitutes a nanomaterial of high value in the biomedical field. However, large scale production of highly stable aqueous dispersions of GOn is yet to be achieved. In this work, we explored high-power ultrasonication as a method to reduce particle size of GO and characterized the impact of the process in the physico-chemical properties of the material. GOn was obtained with lateral dimensions of 99 ±43 nm and surface charge of −39.9 ± 2.2 mV. High-power ultrasonication enabled an improvement of stability features, particularly by resulting in a decrease of the average particle size, as well as zeta potential, in comparison to GO obtained by low-power exfoliation and centrifugation (287 ± 139 nm; −29.7 ± 1.2 mV). Re-markably, GOn aqueous dispersions were stable for up to 6 months of shelf-time, with a global process yield of 74%. This novel method enabled the production of large volumes of highly con-centrated (7.5 mg mL-1) GOn aqueous dispersions. Chemical characterization of GOn allowed the identification of characteristic oxygen functional groups, supporting high-power ultrasonication as a fast, efficient and productive process for reducing GO lateral size, while maintaining the material’s chemical features.

Recolonization dynamics of benthic macroinvertebrates after artificial and natural disturbances in an Australian temporary stream

1991 ◽  
Vol 42 (3) ◽  
pp. 295 ◽  
Author(s):  
SS Brooks ◽  
AJ Boulton
Keyword(s):  
Particle Size ◽  
Species Richness ◽  
Benthic Macroinvertebrates ◽  
Large Scale ◽  
South Australia ◽  
Natural Disturbance ◽  
Small Scale ◽  
Temporary Stream ◽  
Large Scale Disturbance ◽  
Coarse Gravel

The effects of substratum particle size (cobbles, coarse gravel and medium-fine gravel) on recolonization by benthic macroinvertebrates after disturbance was investigated in small plots (0.05 m2) in the Finniss River, an intermittent stream in South Australia. Six weeks after flow resumed, the intermediate particle size (coarse gravel) supported the greatest densities of taxa and individuals. Experimental disturbance reduced species richness by 83% and numbers of individuals by 97%. Rapid recolonizers (e.g. mayfly and stonefly nymphs) showed little substratum specificity and attained predisturbance densities within one day. Slow recolonizers (e.g. chironomid hatchlings) favoured gravel substrata and had not reached predisturbance densities within 4 days. Recolonization of small plots appeared to be by surface movement from neighbouring intact areas. A spate on Day 7 prevented further sampling, destroying all experimental plots, but this permitted a study of macroinvertebrate recolonization following a natural disturbance at a larger spatial scale. The spate reduced species richness by 45% and numbers of individuals by 70%. Vertical migration rather than drift appeared to be the major source of recolonizing fauna. Our data show that results from small-scale experiments can not be extrapolated to large-scale disturbance because the scale of disturbance strongly influences the rate and pathways of recolonization as well as the sources and faunal composition of the recolonists.

Characterization of Hematite Nanoparticles (Fe2O3) Produced by High Energy Milling for Dye Removal Catalyst

2015 ◽  
Vol 819 ◽  
pp. 423-428
Author(s):  
Roshaida Arbain ◽  
Norlia Baharun
Keyword(s):  
Particle Size ◽  
Textile Industry ◽  
Large Scale ◽  
Average Particle Size ◽  
Industrial Effluent ◽  
High Energy ◽  
Average Particle ◽  
Hematite Nanoparticles ◽  
Grinding Technique ◽  
Remazol Red

Hematite nanoparticles with average particle size of 75.6 and 93.4 nm were produced by mechanical grinding technique using planetary ball mill. The ground hematite were characterized by X-ray diffraction analysis technique, specific surface area analysis (BET), transmission microscope (TEM) and scanning electron microscope (SEM). The effects of different properties of hematite particles used as a catalyst for decolorization of synthetic dye, Remazol Red 3B (RR3B) were investigated. The experimental results show that smaller particle size of 75.6 nm decolourized at the rate of 95.8% within 10 min reaction while larger particle size of 93.4 nm decolorized at the rate of 95.9% within 60 min reaction. The decolorization of RR3B dye by both catalyst were achieved with minimum iron leached (<5 mgL-1) which fulfill the Malaysian Environmental Quality (Industrial Effluent) Regulations 2009. The continuous mode for decolorization of RR3B was carried out and complete decolorization was achieved with low iron dissolution which demonstrates the possibilities of using milled hematite as catalyst for large-scale textile industry wastewater treatment applications.

scholarly journals High-Yield Production of Nano-Lateral Size Graphene Oxide by High-Power Ultrasonication

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1916
Author(s):  
Licínia Timochenco ◽  
Raquel Costa-Almeida ◽  
Diana Bogas ◽  
Filipa A. L. S. Silva ◽  
Joana Silva ◽  
...  
Keyword(s):  
Particle Size ◽  
High Power ◽  
Large Scale ◽  
Average Particle Size ◽  
High Yield ◽  
Average Particle ◽  
Scale Production ◽  
Lateral Size ◽  
Aqueous Dispersions ◽  
The Impact

Nanographene oxide (GOn) constitutes a nanomaterial of high value in the biomedical field. However, large scale production of highly stable aqueous dispersions of GOn is yet to be achieved. In this work, we explored high-power ultrasonication as a method to reduce particle size of GO and characterized the impact of the process on the physicochemical properties of the material. GOn was obtained with lateral dimensions of 99 ± 43 nm and surface charge of −39.9 ± 2.2 mV. High-power ultrasonication enabled an improvement of stability features, particularly by resulting in a decrease of the average particle size, as well as zeta potential, in comparison to GO obtained by low-power exfoliation and centrifugation (287 ± 139 nm; −29.7 ± 1.2 mV). Remarkably, GOn aqueous dispersions were stable for up to 6 months of shelf-time, with a global process yield of 74%. This novel method enabled the production of large volumes of highly concentrated (7.5 mg mL−1) GOn aqueous dispersions. Chemical characterization of GOn allowed the identification of characteristic oxygen functional groups, supporting high-power ultrasonication as a fast, efficient, and productive process for reducing GO lateral size, while maintaining the material’s chemical features.

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