scholarly journals Flocculating and dewatering performance of hydrophobic and hydrophilic solids using a thermal-sensitive copolymer

2017 ◽  
Vol 76 (3) ◽  
pp. 694-704 ◽  
Author(s):  
Shulei Li ◽  
Yinfei Liao ◽  
Guosheng Li ◽  
Zhen Li ◽  
Yijun Cao
Keyword(s):  
Solid Surfaces ◽  
Effect Of Temperature ◽  
Solution Temperature ◽  
Adhesion Forces ◽  
Oil Sand ◽  
Floc Size ◽  
Hydrophobic Particles ◽  
Floc Strength ◽  
Solid Liquid ◽  
Solid Liquid Separation

Thermal-sensitive polymers have been tested on settling, compacting or dewatering of clays or oil sand tailings. However, not much attention has been paid to explore the effect of temperature on flocculating performance using thermal-sensitive polymers. In this study, poly(NIPAM-co-DMAPMA) was synthesized and employed to investigate the flocculating and re-flocculating performance of hydrophilic and hydrophobic particles at two specific temperatures; meanwhile settling and dewatering behaviors were also investigated. The results demonstrated that good flocculating performances were achieved at both room temperature (∼23 °C) and lower critical solution temperature (45 °C). Furthermore, larger flocs were formed at 45 °C as the copolymer was added. Floc strength and re-flocculating ability of the flocs were also intensified prominently at 45 °C. Additionally, settling and dewatering rates of suspensions were improved, and the moisture of filtered cakes was reduced when suspensions were at 45 °C. The phenomena could be justified by the phase transition of the copolymer from hydrophilicity to hydrophobicity as the temperature increased. There were much stronger adhesion forces between particles and higher adsorption amount of the copolymer onto solid surfaces at 45 °C. Therefore, the copolymer may be promising in solid–liquid separation to improve the floc size, floc strength, and settling and dewatering rate to achieve much lower moisture filtered cake.

Study on Effectes of Different Inorganic Electrolytes on Flocculation Falling of Slurry

2011 ◽  
Vol 233-235 ◽  
pp. 877-881
Author(s):  
Deng Gao Ji ◽  
Xu Long Guo ◽  
Yang Hui Cai ◽  
Su Qin Peng ◽  
Jian Hua Lian
Keyword(s):  
Zeta Potential ◽  
Functional Groups ◽  
Image Analyzer ◽  
Surface Functional Groups ◽  
Floc Size ◽  
Coal Particles ◽  
Coal Slime ◽  
Solid Liquid ◽  
Solid Liquid Separation ◽  
Better Than

In order to strengthen the thin coal slime settlement, and improve the efficiency of solid-liquid separation, in this paper, as the research object of Wuyang coal slime, carried out the studies on the effect of flocculation and settling with different inorganic electrolytes, and using electrophoresis analyzer, image analyzer and FTIR, characterized inorganic electrolytes effect on zeta potential of coal particles, floc size and surface functional groups. The results showed that: the effect of flocculation and falling, with CaCl2 and non-ionic PAM, is better than several other inorganic electrolytes. When the amount of non-ionic PAM is 3ml, CaCl2 best dosage is 4ml, corresponding to the initial falling speed is 24.49cm/min, supernatant turbidity is 22NTU. It has certain effect to the zeta potential of coal particles, floc size and the functional groups of coal surface after adding inorganic electrolytes.

Nutrient conditions and reactor configuration influence floc size distribution and settling properties

2012 ◽  
Vol 65 (1) ◽  
pp. 156-163 ◽  
Author(s):  
G. A. C. Ehlers ◽  
D. Wagachchi ◽  
S. J. Turner
Keyword(s):  
Size Distribution ◽  
Nutrient Concentrations ◽  
Size Analysis ◽  
Liquid Separation ◽  
Floc Size ◽  
Treatment Processes ◽  
Floc Size Distributions ◽  
Solid Liquid ◽  
Solid Liquid Separation ◽  
Nutrient Conditions

Floc formation and settleability is critical for effective solid–liquid separation in many wastewater treatment processes. This study aimed to investigate the relationship between particle size distribution and nutrient conditions in different bioreactor configurations. Size distribution profiles of flocs that formed in continuous (B1), continuous with clarifier and return sludge (B2) and SBR (B3) reactors were investigated in parallel under identical nutrient conditions. An eight-fold dilution of the influent COD of a synthetic dairy processing wastewater resulted in a ‘feast and famine’ regime that triggered significant effects on the biomass and flocculation characteristics. Floc size analysis of reactor MLSS revealed a shift in floc sizes when reactors were fed with the minimum (famine) COD wastewater feed (0.61 g L−1). Increasing floc size distributions were detected for all reactors during the minimum COD feed although different size patterns were observed for different reactor configurations. These increases corresponded with variations in aggregation and EPS quantities. The SBR yielded comparatively larger flocs when operated under both COD feeds as indicated by d(0.9) values (90% of particles ≤ d in size). Overall the results indicated that floc formation and floc size are mediated by nutrient concentrations and represents an important step towards improved solid–liquid separation.

Nitrogen Removal in a Real-Time Controlled Sequencing Batch Membrane Bioreactor

2010 ◽  
Vol 5 (3) ◽  
Author(s):  
Cheng-Nan Chang ◽  
Li-Ling Lee ◽  
Han-Hsien Huang ◽  
Ying-Chih Chiu
Keyword(s):  
Real Time ◽  
Nitrogen Removal ◽  
Membrane Bioreactor ◽  
Synthetic Wastewater ◽  
Real Time Control ◽  
Time Control ◽  
Cake Layer ◽  
On Line ◽  
Solid Liquid ◽  
Solid Liquid Separation

The performance of a real-time controlled Sequencing Batch Membrane Bioreactor (SBMBR) for removing organic matter and nitrogen from synthetic wastewater has been investigated in this study under two specific ammonia loadings of 0.0086 and 0.0045g NH4+-N gVSS−1 day−1. Laboratory results indicate that both COD and DOC removal are greater than 97.5% (w/w) but the major benefit of using membrane for solid-liquid separation is that the effluent can be decanted through the membrane while aeration is continued during the draw stage. With a continued aeration, the sludge cake layer is prevented from forming thus alleviating the membrane clogging problem in addition to significant nitrification activities observed in the draw stage. With adequate aeration in the oxic stage, the nitrogen removal efficiency exceeding 99% can be achieved with the SBMBR system. Furthermore, the SBMBR system has also been used to study the occurrence of ammonia valley and nitrate knee that can be used for real-time control of the biological process. Under appropriate ammonia loading rates, applicable ammonia valley and nitrate knee are detected. The real-time control of the SBMBR can be performed based on on-line ORP and pH measurements.

Investigations on the filtration of natural aquatic suspensions supported by dosing small amounts of Fe(III)-salts (βFe ≤ 0.1 mg.L-1): mode of action and basic design criteria

2002 ◽  
Vol 2 (2) ◽  
pp. 91-98
Author(s):  
R. Winzenbacher ◽  
R. Schick ◽  
H.-H. Stabel ◽  
M. Jekel
Keyword(s):  
Large Scale ◽  
Suspended Solids ◽  
Iron Hydroxides ◽  
Essential Step ◽  
Iron Salts ◽  
Alkaline Earths ◽  
Co Precipitation ◽  
Solid Liquid ◽  
Solid Liquid Separation

Improved removal of particles during the treatment of natural aquatic suspensions has been achieved by pre-ozonation and the addition of small quantities of iron salts (βFe ≤ 0.1 mg.L-1; “Fe(III)-assisted filtration”) followed by rapid filtration. As shown by investigations on a large-scale installation at Lake Constance Water Supply, this procedure reliably reduces suspended solids by at least 2-3 powers of ten in long-term use. However, the high efficacy of Fe(III)-assisted filtration cannot be explained on the basis of known coagulation mechanisms (like adsorption-charge neutralization, co-precipitation). Instead, the essential step was found to be the conditioning of the filter medium by coating it with colloids containing Fe(OH)3, and this “Fe coating” process occurs only in the presence of alkaline earths (especially Ca2+). According to further experiments, the enhanced solid-liquid separation was ultimately traced to chemical interactions such as the formation of calcium-organic association structures between the iron hydroxides and other solids. For design of Fe(III)-assisted filtration steps, finally, a βCa/DOC ratio above 40 mg.mg-1 and pre-oxidation with ozone dosages not exceeding 2 mg O3/mg DOC was recommended.

scholarly journals Controlling the breakup of toroidal liquid films on solid surfaces

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrew M. J. Edwards ◽  
Élfego Ruiz-Gutiérrez ◽  
Michael I. Newton ◽  
Glen McHale ◽  
Gary G. Wells ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Mode Selection ◽  
Liquid Films ◽  
Solid Surfaces ◽  
Final States ◽  
Digital Microfluidic ◽  
Insulating Liquid ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Dynamics Stability

AbstractThe breakup of a slender filament of liquid driven by surface tension is a classical fluid dynamics stability problem that is important in many situations where fine droplets are required. When the filament is resting on a flat solid surface which imposes wetting conditions the subtle interplay with the fluid dynamics makes the instability pathways and mode selection difficult to predict. Here, we show how controlling the static and dynamic wetting of a surface can lead to repeatable switching between a toroidal film of an electrically insulating liquid and patterns of droplets of well-defined dimensions confined to a ring geometry. Mode selection between instability pathways to these different final states is achieved by dielectrophoresis forces selectively polarising the dipoles at the solid-liquid interface and so changing both the mobility of the contact line and the partial wetting of the topologically distinct liquid domains. Our results provide insights into the wetting and stability of shaped liquid filaments in simple and complex geometries relevant to applications ranging from printing to digital microfluidic devices.

Solid–liquid–liquid phase envelopes from temperature-scanned refractive index data

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alcides J. Sitoe ◽  
Franco Pretorius ◽  
Walter W. Focke ◽  
René Androsch ◽  
Elizabeth L. du Toit
Keyword(s):  
Refractive Index ◽  
Liquid Phase ◽  
Volume Fraction ◽  
Solution Temperature ◽  
Linear Behavior ◽  
Upper Critical Solution Temperature ◽  
Novel Method ◽  
Using Data ◽  
Solid Liquid ◽  
Liquid Liquid Phase Separation

Abstract A novel method for estimating the upper critical solution temperature (UCST) of N,N-diethyl-m-toluamide (DEET)-polyethylene systems was developed. It was validated using data for the dimethylacetamide (DMA)-alkane systems which showed that refractive index mixing rules, linear in volume fraction, can accurately predict mixture composition for amide-alkane systems. Furthermore, rescaling the composition descriptor with a single adjustable parameter proved adequate to address any asymmetry when modeling the DMA-alkane phase envelopes. This allowed the translation of measured refractive index cooling trajectories of DEET-alkane systems into phase diagrams and facilitated the estimation of the UCST values by fitting the data with an adjusted composition descriptor model. For both the DEET- and DMA-alkane systems, linear behavior of UCST values in either the Flory–Huggins critical interaction parameter, or the alkane critical temperature, with increasing alkane molar mass is evident. The UCST values for polymer diluent systems were estimated by extrapolation using these two complimentary approaches. For the DEET-polyethylene system, values of 183.4 and 180.1 °C respectively were obtained. Both estimates are significantly higher than the melting temperature range of polyethylene. Initial liquid–liquid phase separation is therefore likely to be responsible for the previously reported microporous microstructure of materials formed from this binary system.

scholarly journals Fundamental Study of Palladium Recycling Using “Dry Aqua Regia” Considering the Recovery from Spent Auto-catalyst

2021 ◽  
Author(s):  
Akihiro Yoshimura ◽  
Shunta Tochigi ◽  
Yasunari Matsuno
Keyword(s):  
Potassium Chloride ◽  
Platinum Group Metals ◽  
Recycling Process ◽  
Fundamental Study ◽  
Aqua Regia ◽  
Sodium Chloride Solutions ◽  
Pure Compounds ◽  
The Difference ◽  
Solid Liquid ◽  
Solid Liquid Separation

AbstractIn this research, a recycling process for palladium using “dry aqua regia,” which consists of iron(III) chloride–potassium chloride, was proposed. Palladium was dissolved in “dry aqua regia,” and the dissolved palladium was recovered by leaching with potassium chloride solution with added ammonium chloride and nitric acid. Palladium was almost completely dissolved in 3 h at 600 K, and the recovery ratio of dissolved palladium was up to 80%. In addition, the dissolution of palladium in coexistence with platinum and the dissolution of platinum-palladium alloy by “dry aqua regia” were also tested. The dissolved palladium and platinum were separated and recovered by solid–liquid separation technique using the difference in solubility of their compounds in potassium chloride and sodium chloride solutions. As a result, pure compounds of each element were recovered. This result suggested the possibility of using “dry aqua regia” for the separation of platinum-group metals. Graphical Abstract

Sign in / Sign up

Export Citation Format

Share Document