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1.
Zhonghua Nei Ke Za Zhi ; 61(4): 377-383, 2022 Apr 01.
Article in Zh | MEDLINE | ID: mdl-35340183

ABSTRACT

Objective: To explore the differences of risk stratification of very high-risk or extreme high-risk atherosclerotic cardiovascular diseases (ASCVD) and the attainment rates of low-density lipoprotein cholesterol (LDL-C) management targets evaluated by three different criteria, and the causal attributions of these differences. Methods: Patients with ASCVD were consecutively enrolled from January 1 to December 31 in 2019, and were evaluated for very high-risk or extreme high-risk and LDL-C goal attainment rates with 2018 American guideline on the management of blood cholesterol (2018AG), 2019 China Cholesterol Education Program (CCEP) Expert Advice for the management of dyslipidemias (2019EA) and 2020 Chinese expert consensus on lipid management of very high-risk ASCVD patients(2020EC), respectively. The causal attributions of the differences in attainment rates were analyzed as well. Results: A total of 1 864 ASCVD patients were included in this study. According to 2018AG, 2019EA and 2020EC, the proportions of the patients with very high-risk or extreme high-risk were 59.4%, 90.7%, and 65.6%, respectively. The absolute LDL-C target attainment rates were 37.2%, 15.7%, and 13.7%, respectively, the differences between each two rates were statistically significant (all P<0.001). As to the differences in attainment rates between 2020EC and 2018AG, 61.5% were due to the different LDL-C goal attainment values and 38.5% were caused by the different risk stratifications, while for the differences between 2020EC and 2019EA attainment rates, different LDL-C goal attainment values were responsible for 13.2%, and different risk stratifications were responsible for 86.8% of the differences. Conclusions: There are significant differences in the proportions and LDL-C attainment rates among the three different criteria for very high-risk or extreme high-risk ASCVD. 2020EC showed a moderate proportion of patients with extreme high-risk, and had the lowest LDL-C attainment rate. The differences between 2020EC and 2018AG are mainly due to the LDL-C target values, and the differences between 2020EC and 2019EA are mainly caused by the risk stratifications.


Subject(s)
Cardiovascular Diseases , Cholesterol , Cholesterol, LDL , Goals , Humans , Risk Assessment
2.
Zhonghua Yi Xue Za Zhi ; 98(17): 1302-1305, 2018 May 08.
Article in Zh | MEDLINE | ID: mdl-29764028

ABSTRACT

Objective: To explore the clinical and teaching application value of virtual reality technology in preoperative planning and intraoperative guide of glioma located in central sulcus region. Method: Ten patients with glioma in the central sulcus region were proposed to surgical treatment. The neuro-imaging data, including CT, CTA, DSA, MRI, fMRI were input to 3dgo sczhry workstation for image fusion and 3D reconstruction. Spatial relationships between the lesions and the surrounding structures on the virtual reality image were obtained. These images were applied to the operative approach design, operation process simulation, intraoperative auxiliary decision and the training of specialist physician. Results: Intraoperative founding of 10 patients were highly consistent with preoperative simulation with virtual reality technology. Preoperative 3D reconstruction virtual reality images improved the feasibility of operation planning and operation accuracy. This technology had not only shown the advantages for neurological function protection and lesion resection during surgery, but also improved the training efficiency and effectiveness of dedicated physician by turning the abstract comprehension to virtual reality. Conclusion: Image fusion and 3D reconstruction based virtual reality technology in glioma resection is helpful for formulating the operation plan, improving the operation safety, increasing the total resection rate, and facilitating the teaching and training of the specialist physician.


Subject(s)
Glioma , Humans , Imaging, Three-Dimensional , Magnetic Resonance Imaging , Multimodal Imaging , User-Computer Interface , Virtual Reality
3.
J Environ Manage ; 147: 194-202, 2015 Jan 01.
Article in English | MEDLINE | ID: mdl-25291677

ABSTRACT

Polymerized inorganic coagulants are increasingly being used in the water supply and wastewater treatment process, yet there is limited research on the development of polytitanium coagulants. The aim of this study is to synthesize polytitanium chloride (PTC) coagulants and investigate their coagulation behavior and floc characteristics for humic acid removal in comparison to polyaluminum chloride (PAC). The PTC samples with different B (molar ratios of OH/Ti) values were prepared using an instantaneous base-feeding method, employing sodium carbonate as the basification agent. The coagulation efficiency was significantly influenced by different B values. The results suggest that the humic acid removal increased with the increasing B value for PAC, while the inverse trend was observed for PTC. The optimum B value was chosen at 1.0 and 2.0 for PTC and PAC, respectively. Under the optimum coagulant dose and initial solution pH conditions, the PTC coagulant performed better than the PAC coagulant and the floc properties were significantly improved in terms of floc growth rate and floc size. However, the PAC coagulants produced flocs with better floc recoverability than the PTC coagulants.


Subject(s)
Aluminum Hydroxide/chemistry , Chemical Precipitation , Chlorides/chemistry , Polymers/chemistry , Titanium/chemistry , Water Pollutants, Chemical/chemistry , Alkalies , Flocculation , Humic Substances , Solutions , Water Purification/methods
4.
J Environ Manage ; 134: 20-9, 2014 Feb 15.
Article in English | MEDLINE | ID: mdl-24463732

ABSTRACT

This study is the first attempt to investigate the effect of total hardness and ionic strength on coagulation performance and the floc characteristics of titanium tetrachloride (TiCl4). Membrane fouling under different total hardness and ionic strength conditions was also evaluated during a coagulation-ultrafiltration (C-UF) hybrid process. Coagulation experiments were performed with two simulated waters, using humic acid (HA, high molecular weight) and fulvic acid (FA, relatively low molecular weight), respectively, as model natural organic matter (NOM). Results show that both particle and organic matter removal can be enhanced by increasing total hardness and ionic strength. Floc characteristics were significantly influenced by total hardness and ionic strength and were improved in terms of floc size, growth rate, strength, recoverability and compactness. The results of the UF tests show that the pre-coagulation with TiCl4 significantly improves the membrane permeate fluxes. Under different total hardness and ionic strength conditions, the membrane permeate flux varied according to both NOM and floc characteristics. The increase in total hardness and ionic strength improved the membrane permeate flux in the case of HA simulated water treatment.


Subject(s)
Benzopyrans/chemistry , Humic Substances , Titanium/chemistry , Water Pollutants/chemistry , Water Purification/methods , Flocculation , Hardness , Membranes, Artificial , Osmolar Concentration , Ultrafiltration/methods
5.
Environ Sci Technol ; 47(22): 12966-75, 2013 Nov 19.
Article in English | MEDLINE | ID: mdl-24106890

ABSTRACT

Polymeric metal coagulants are increasingly being used to improve coagulation efficiency, yet the research on the development of titanium and particularly polytitanium salts remains limited. This study is the first attempt in the synthesis, characterization, and application of polytitanium salts as coagulants. Polytitanium tetrachloride (PTC) solutions with different basicity values B (OH/Ti molar ratio) were prepared using a slow alkaline titration method. Jar tests were conducted to assess coagulation performance using both synthetic and real raw water samples, and the floc characteristics were monitored online using a laser diffraction particle size analyzer. Electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) was utilized to identify various Ti species, with the results providing strong evidence of the presence of various hydrolyzed Ti species in the titanium aqueous phase. Compared to titanium tetrachloride (TiCl4), higher or comparable turbidity and organic matter removal efficiency could be achieved by PTC with improved floc characteristics in terms of size, growth rate, and structure. Besides, the water pH after PTC coagulation was significantly improved toward neutral pH. This study indicates that PTC is an effective and promising coagulant for water purification. Besides, the PTC flocculated sludge was able to recycle and produce functional TiO2 photocatalyst.


Subject(s)
Titanium/chemistry , Water Purification/methods , Flocculation , Fractals , Polymers/chemistry , Rivers/chemistry , Sewage/chemistry , Solutions , Spectrometry, Mass, Electrospray Ionization , Water/chemistry , X-Ray Diffraction
6.
J Hazard Mater ; 152(1): 221-7, 2008 Mar 21.
Article in English | MEDLINE | ID: mdl-17689006

ABSTRACT

Polyamine flocculants were synthesized by the polycondensation of dimethylamine and epichlorohydrin, in which organic amines, e.g. 1,2-diaminoethane, were used as modifying agents. Different products were obtained by varying the reaction parameters, such as the molar ratio of epichlorohydrin to dimethylamine, the amount of 1,2-diaminoethane and reaction temperature. The polyamine flocculants were characterized by transmission electron microscope (TEM). Their flocculation performance was evaluated with simulated dye liquor and actual printing and dyeing wastewater. The behavior of the flocculants was compared with that of inorganic coagulant, polyaluminum chloride (PAC). The experimental results show that polyamine with the highest viscosity and cationicity could be prepared under following conditions: an epichlorohydrin to dimethylamine molar ratio of 1.5, a reaction temperature of 70 degrees C, a 3% content of 1,2-diaminoethane in the total reaction monomers and a reaction time of 7h. Polyamine polymers can, as flocculants for treating simulated and actual dye wastewater, remove color and COD efficiently. The rate of color removal from reactive red liquor, reactive blue liquor and reductive yellow liquor reached as high as 96%, 97% and 96%, respectively. The highest efficiency of color removal and COD removal from polyamine for treating dye wastewater was 90% and 89%, respectively.


Subject(s)
Coloring Agents/isolation & purification , Flocculation , Industrial Waste , Polyamines/chemical synthesis , Water Pollutants, Chemical/isolation & purification , Microscopy, Electron, Transmission
7.
Rev Sci Instrum ; 78(11): 113503, 2007 Nov.
Article in English | MEDLINE | ID: mdl-18052470

ABSTRACT

A new multichannel HCN interferometer has been developed on HL-2A tokamak, which is characterized by two techniques: (1) the wave-guide HCN laser with cavity length of 6 m to increase the optical resource power and (2) high response room temperature waveguide Schottky diode detectors to obtain good beat signal. The space resolution is 7 cm by the use of focusing metal mirrors mounted on the vacuum chamber and a compensated optical system. In the 2006 experiment campaign, this new interferometer has been applied for plasma density profile and density sawtooth measurement.

8.
Environ Technol ; 28(6): 629-37, 2007 Jun.
Article in English | MEDLINE | ID: mdl-17624103

ABSTRACT

In this study, the decolorization of textile wastewater using composite flocculants was examined. It was composed of Fe(III) flocculants and polydimethyldiallylammonium chloride (PDMDAAC). The color removal efficiency of the composite flocculants was compared with that of individual flocculants, ferric chloride (FeCl3), polyferric chloride (PFC) and PDMDAAC, respectively. The results showed that the composite flocculants were more efficient than individual ones in color removal. The color removal efficiency of the composite flocculants was found to be related to the weight percentage of PDMDAAC (Wp), basicity (B) of PFC and molecular weight (MW) of PDMDAAC. The removal rate is higher at a larger Wp and MW value and lower B value. Chemical oxygen demand (COD) removal from textile wastewater was also investigated in this study. During color removal by the composite flocculants, only up to 20% COD could be removed from the textile wastewater. FeCl3 was then used to further remove the remaining COD from the decolorized wastewater. This two-step treatment of textile wastewater could achieve a 91.6% reduction in COD and an 88.9% reduction in color.


Subject(s)
Color , Flocculation , Industrial Waste , Textile Industry , Water Pollutants, Chemical/isolation & purification , Environmental Restoration and Remediation/instrumentation , Environmental Restoration and Remediation/methods
9.
J Hazard Mater ; 284: 190-200, 2015 Mar 02.
Article in English | MEDLINE | ID: mdl-25463233

ABSTRACT

Adsorption of natural organic matter, aggregation and disaggregation have been identified as three of the main processes affecting the fate and behaviour of engineered nanoparticles (ENPs) in aquatic environments. However, although several methods have been developed to study the aggregation behaviour of ENPs in natural waters, there are only a few studies focusing on the fate of such aggregates and their potential disaggregation behaviour. In this study, we proposed and demonstrated a simple method for characterising the aggregation behaviour and aggregate structure of ENPs in different natural waters. Both the aggregate size of ENPs and their adsorption capacity for dissolved organic matter (DOM) were strongly related (R(2)>0.97, p<.05) to the combined effect of initial concentration of dissolved organic matter (DOM) and the ionic strength of the natural waters. The structure of the formed aggregates was strongly correlated (R(2)>0.95, p<.05) to the amount of DOM adsorbed by the ENPs during the aggregation process. Under high ionic strength conditions, aggregation is mainly governed by diffusion and the aggregates formed under these conditions showed the lowest stability and fractal dimension, forming linear, chain-like aggregates. In contrast, under low ionic strength conditions, the aggregate structure was more compact, most likely due to strong chemical binding with DOM and bridging mechanisms involving divalent cations formed during reaction-limited aggregation.


Subject(s)
Nanoparticles/chemistry , Water Pollutants, Chemical/chemistry , Water Purification/methods , Adsorption , Calcium/chemistry , Ferric Compounds/chemistry , Fractals , Humic Substances/analysis , Ions , Lasers , Light , Organic Chemicals/chemistry , Osmolar Concentration , Particle Size , Regression Analysis , Scattering, Radiation , Shear Strength , Surface Properties , Water/chemistry
10.
Water Res ; 36(14): 3573-81, 2002 Aug.
Article in English | MEDLINE | ID: mdl-12230203

ABSTRACT

Aluminum-silicate polymer composite (PASiC), a new kind of inorganic coagulant, was produced by two approaches: (1) hydroxylation of the mixture of AlCl3 and fresh polysilicate (PASiCc); (2) hydroxylated polyaluminum-chloride (PAC) combined with fresh polysilicate (PASiCm). The PASiC products had the following properties: Al2O3 content = 6.40-7.30%, SiO2 content = 0.40-0.82%, Al/Si ratios = 10-20, basicity (OH/Al molar ratio, denoted B) = 1.2-2.0. The coagulation behaviour of PASiC and PAC under conditions typical for coagulation and flocculation in water treatment were investigated by studying the rate of floc size development, the variety of streaming current value, the efficiency of turbidity removal and the effect of pH on the turbidity removal efficiency, and the stability of PASiC. The results detailed in this study suggest that, compared with PAC, PASiC may enhance aggregating efficiency and give better coagulating effects, but weaken charge effectiveness in coagulation process or become unstable when stored for longer time, especially at higher B value and lower Al/Si ratio. The coagulating effect of PASiC is closely linked to the preparation procedure. With the increase of B value and the decrease of Al/Si ratio, the coagulation efficiency of PASiC increases, and at the same B value and Al/Si ratio, PASiCc seems to give a little better coagulation effect than PASiCm but less stability. The Al/Si ratio should not be too low or the B value should not be too high, otherwise, the PASiC products tend to become cloudy or partly gelatinous, which will make them loss some coagulation efficiency.


Subject(s)
Aluminum Silicates/chemistry , Water Purification/methods , Kinetics , Polymers
11.
Yao Xue Xue Bao ; 27(9): 641-4, 1992.
Article in Zh | MEDLINE | ID: mdl-1293932

ABSTRACT

PTS, one of the major effective components of Panax notoginseng was found to exert remarked antiarrhythmic activities on coronary artery ligation induced ischemic and reperfused arrhythmias in rats. PTS also reduced the size of myocardial infarct. For i.v. CaCl2-Ach induced atrial fibrillation and/or flutter in mice, PTS produced a significant protective effect. In addition, PTS showed an action of prolonging the life under the condition of normobaric hypoxia.


Subject(s)
Anti-Arrhythmia Agents/therapeutic use , Arrhythmias, Cardiac/drug therapy , Ginsenosides , Triterpenes/therapeutic use , Animals , Arrhythmias, Cardiac/etiology , Atrial Fibrillation/prevention & control , Atrial Flutter/prevention & control , Female , Male , Mice , Myocardial Ischemia/complications , Myocardial Reperfusion Injury/complications , Rats , Rats, Wistar , Saponins/therapeutic use
12.
J Environ Sci (China) ; 13(1): 108-14, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11590710

ABSTRACT

A series of poly-aluminum-chloride-sulfate (PACS), which has different basicities (gamma) and Al3+/SO4(2-) molar ratio, has been prepared and dried at 105 degrees C and 65 degrees C, respectively. The distribution of aluminum species of PACS was examined, and the effect of gamma value, Al3+/SO4(2-) molar ratio, dilution on the distribution of aluminum species of PACS was also investigated by using Alferron timed complex colorimetric method. The IR spectroscopy and X-ray diffraction were used to study the effect of gamma value, Al3+/SO4(2-) molar ratio and the drying temperature on the structure of PACS. The experimental results show that Al3+/SO4(2-) molar ratio has a great effect on the distribution of aluminum species, but the dilution has a little effect on the distribution of aluminum species. The lower the Al3+/SO4(2-) molar ratio, the higher the proportions of the polymer and colloidal species in PACS. The polymeric degree of PACS was related to gamma value and Al3+/SO4(2-) molar ratio. Drying temperature has an influence on the structure and the solubility of solid PACS products.


Subject(s)
Alum Compounds/chemistry , Aluminum Compounds/chemistry , Chlorides/chemistry , Aluminum Chloride , Colorimetry , Flocculation , Sodium Bicarbonate/chemistry , Spectrophotometry, Infrared , Water Purification/methods , X-Ray Diffraction
13.
Zhonghua Wai Ke Za Zhi ; 27(9): 531-4, 573-4, 1989 Sep.
Article in Zh | MEDLINE | ID: mdl-2560964

ABSTRACT

This article reports the surgical treatment to 51 patients with mid and advanced hepatocarcinoma by the self-made implantable microwave radiation apparatus from April, 1987 to April 1989. By way of histology, histochemistry, and electronic microscopy, we studied the killing effect on cancer cells, the range of the effect and the remarkable hemostatic mechanism of this implantable microwave device. Clinically, we developed six different methods of operate with the microwave. Without the need of blocking hepatic portal, this new approach simplifies the operation. The risk of iatrogenic cancerous diffusion and hemorrhage is also greatly reduced or prevented in hemihepatectomy. Initial results shows that the resection rate of the hepatocarcinoma went up from 20-42.5 percent to 74.5 percent. Microwave operation on 38 patients with advanced hepatocarcinoma reveals a survival rate of 75 percent over 6 months. The authors believe that this new operative method is effective in the treatment to advanced hepatic carcinoma, and prolongs the life of the patients.


Subject(s)
Carcinoma, Hepatocellular/surgery , Liver Neoplasms/surgery , Microwaves/therapeutic use , Adolescent , Adult , Carcinoma, Hepatocellular/radiotherapy , Child , Female , Hemostasis, Surgical , Hepatectomy/methods , Humans , Liver Neoplasms/radiotherapy , Male , Microscopy, Electron , Middle Aged
14.
J Hazard Mater ; 258-259: 84-92, 2013 Aug 15.
Article in English | MEDLINE | ID: mdl-23708450

ABSTRACT

This is the first attempt to use cationic polyacrylamide (PAM) as coagulant aid with titanium tetrachloride (TiCl4) to improve the coagulation performance and floc properties. Coagulation-flocculation treatment was applied to simulated water (with fulvic acid (FA) as model organic matter) for both coagulation behavior investigation and floc characterization. The effect of PAM on floc reformation properties after cyclic breakage/regrowth was also investigated. Ultrafiltration experiments were performed to investigate the influence of PAM aided TiCl4 coagulation on the membrane fouling. The results showed that organic removal was enhanced by PAM addition at low TiCl4 doses. Floc growth rate and floc size were significantly affected by dosing sequence. TiCl4-PAM significantly improved the floc strength factors (Sf) and recovery factors (Rf). The dosing sequence of TiCl4 and PAM significantly influenced the floc structure. Characterization of the flocculated sludge indicated that TiO2 with anatase structure and high photocatalytic activity could be obtained from the TiCl4-PAM flocculated sludge.


Subject(s)
Acrylic Resins/chemistry , Titanium/chemistry , Water Purification/methods , Water/chemistry , Flocculation , Hydrogen-Ion Concentration
15.
Bioresour Technol ; 108: 45-54, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22284758

ABSTRACT

The objectives of this study are to investigate the impacts of anionic polymer compound bioflocculant (CBF) as a coagulant aid on coagulation performance and floc characteristics with titanium tetrachloride (TiCl(4)) and aluminum sulfate (Al(2)(SO(4))(3)). The effect of dosing sequence was also investigated. Floc size, breakage, regrowth and floc fractal dimension were examined using a laser diffraction instrument. The results showed that CBF with TiCl(4) or Al(2)(SO(4))(3) coagulants exhibited synergistic effects by promoting dissolved organic carbon (DOC) removal. For both TiCl(4) and Al(2)(SO(4))(3), the floc recoverability was improved by CBF addition, and the flocs formed by TiCl(4) and the corresponding dual-coagulants showed weaker recovery ability than those by Al(2)(SO(4))(3) and the corresponding dual-coagulants. Fractal dimension analysis demonstrated that the floc fractal dimension values increased with the increasing coagulant dose. The effect of CBF on fractal dimension of the flocs generated by TiCl(4) was different from that of Al(2)(SO(4))(3).


Subject(s)
Alum Compounds/chemistry , Polymers/chemistry , Titanium/chemistry , Waste Disposal, Fluid/methods , Water Purification/methods , Anions , Flocculation , Models, Chemical
16.
J Hazard Mater ; 187(1-3): 495-501, 2011 Mar 15.
Article in English | MEDLINE | ID: mdl-21310529

ABSTRACT

The growth, breakage and regrowth nature of flocs formed by Titanium tetrachloride (TiCl(4)) and polyaluminum chloride (PACl) was comparatively evaluated with surface water treatment. A series of jar experiments were conducted to investigate the impacts of different operating parameters such as shear force, solution pH and a breakage period on floc strength and re-aggregation potential. Results indicated that the responses of flocs to different operating parameters depend on the coagulant used. The ability of floc to resist breakage decreased with the increase of shear force and breakage period. Floc strength properties were also measured in response to increasing shear force, with the results suggesting that the order of floc strength was TiCl(4)>PACl. Floc regrowth of the two coagulants after exposure to high shear was limited, and flocs formed by TiCl(4) displayed weaker recoverability. The flocs generated in acid conditions were more recoverable than those generated in alkaline conditions no matter which coagulant was used.


Subject(s)
Aluminum Hydroxide/chemistry , Hydrogen-Ion Concentration , Titanium/chemistry , Flocculation , Solutions
17.
J Hazard Mater ; 198: 70-7, 2011 Dec 30.
Article in English | MEDLINE | ID: mdl-22030273

ABSTRACT

Characteristics of flocs formed by charge neutralization and sweep coagulation using titanium tetrachloride (TiCl(4)) were investigated with humic acid-kaolin suspension by continuous optical monitoring. This paper focused on the regrowth ability of broken flocs after addition of second TiCl(4) dose. Variation of floc size and the fractal dimension of flocs versus second TiCl(4) dose after regrowth were investigated. Second TiCl(4) dose was added during the floc breakage period, and addition time of second TiCl(4) dose was also investigated. The results showed that, when coagulated by charge neutralization at pH 6, an appropriate second TiCl(4) dose improved regrowth ability of broken flocs at low initial TiCl(4) doses. While for high initial TiCl(4) doses, second TiCl(4) dose lowered floc re-growth ability. When coagulated by sweep coagulation at pH 10, second TiCl(4) dose made regrown flocs larger than those without second TiCl(4) dose. Floc structure analysis showed that it was determined by not only the fractal dimension of flocs, but also the chemical characteristics of floc surface. Addition time of second TiCl(4) dose had a great effect on floc regrowth ability, suggesting that the broken flocs had better regrowth when second TiCl(4) dose was added at the end of the breakage period.


Subject(s)
Titanium/chemistry , Flocculation
18.
J Hazard Mater ; 185(2-3): 1536-42, 2011 Jan 30.
Article in English | MEDLINE | ID: mdl-21075521

ABSTRACT

In this study, the performance of titanium tetrachloride (TiCl(4)) coagulation and flocculation is compared with commonly used coagulants such as aluminum sulfate (Al(2)(SO(4))(3)), polyaluminum chloride (PACl), iron chloride (FeCl(3)), and polyferric sulfate (PFS) in terms of water quality parameters and floc properties. TiCl(4) flocculation achieved higher removal of UV(254) (98%), dissolved organic carbon (DOC) (84%) and turbidity (93%) than other conventional coagulants. Charge neutralization and physical entrapment of colloids within coagulant precipitates and adsorption, seemed to play a significant role during TiCl(4) flocculation, while the main mechanism for conventional coagulants was bridge-aggregation and adsorption. The aggregated flocs after TiCl(4) flocculation showed the fastest growth rate compared to the other coagulants, with the largest floc size (801 µm) occurring within 8 min. The floc strength factor of PACl, Al(2)(SO(4))(3), PFS, FeCl(3) and TiCl(4) was 34, 30, 29, 26 and 29, respectively, while the floc recovery factor of the TiCl(4) coagulant was the lowest. Based on the results of the above study, it is concluded that the TiCl(4) flocculation can reduce the hydraulic retention time of slow and rapid mixing, however, careful handling of sludge is required due to the low recoverability of the aggregated floc.


Subject(s)
Aluminum/chemistry , Iron/chemistry , Salts/chemistry , Titanium/chemistry , Adsorption , Flocculation , Hydrogen-Ion Concentration , Spectrophotometry, Ultraviolet
19.
J Hazard Mater ; 175(1-3): 949-54, 2010 Mar 15.
Article in English | MEDLINE | ID: mdl-19939559

ABSTRACT

The floc strength and regrowth properties of three polyferric-cationic polymer dual-coagulants were comparatively evaluated using surface water sample. The first dual-coagulant PFC-PD was prepared by premixing of polyferric chloride (PFC) and polydiallyldimethylammonium (PDADMAC) before dosing. The other two, PFCF (PFC dosed firstly) and PDF (PDADMAC dosed firstly), were achieved by dosing PFC and PDADMAC in different order. Floc strength properties were measured in response to increasing shear levels in the long period and high shear level in the short or long period. For the given optimum dose (3.0 mg L(-1)) and water pH (6.5) condition, the order of floc strength was PFCF>PDF>PFC-PD. The dual-coagulant which gave stronger flocs also gave a lower absolute value of zeta potential. The floc regrowth properties of all three dual-coagulants after short and long period high shear level were also investigated. The floc recoverability was in the following order: PFCF>PFC-PD>PDF.


Subject(s)
Ferric Compounds/chemistry , Iron/chemistry , Polymers/chemistry , Waste Disposal, Fluid/methods , Water Purification/methods , Coagulants/chemistry , Hydrogen-Ion Concentration , Particle Size , Polyethylenes/chemistry , Quaternary Ammonium Compounds/chemistry , Temperature , Time Factors , Water/chemistry , Water Pollutants, Chemical/analysis
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