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ABSTRACT: The corrosion scales on iron pipes could have great impact on the water quality in drinking water distribution systems (DWDS). Unstable and less protective corrosion scale is one of the main factors causing "discolored water" issues when quality of water entering into distribution system changed significantly. The morphological and physicochemical characteristics of corrosion scales formed under different source water histories in duration of about two decades were systematically investigated in this work. Thick corrosion scales or densely distributed corrosion tubercles were mostly found in pipes transporting surface water, but thin corrosion scales and hollow tubercles were mostly discovered in pipes transporting groundwater. Magnetite and goethite were main constituents of iron corrosion products, but the mass ratio of magnetite/goethite (M/G) was significantly different depending on the corrosion scale structure and water source conditions. Thick corrosion scales and hard shell of tubercles had much higher M/G ratio (>1.0), while the thin corrosion scales had no magnetite detected or with much lower M/G ratio. The M/G ratio could be used to identify the characteristics and evaluate the performances of corrosion scales formed under different water conditions. Compared with the pipes transporting ground water, the pipes transporting surface water were more seriously corroded and could be in a relatively more active corrosion status all the time, which was implicated by relatively higher siderite, green rust and total iron contents in their corrosion scales. Higher content of unstable ferric components such as γ-FeOOH, β-FeOOH and amorphous iron oxide existed in corrosion scales of pipes receiving groundwater which was less corroded. Corrosion scales on groundwater pipes with low magnetite content had higher surface area and thus possibly higher sorption capacity. The primary trace inorganic elements in corrosion products were Br and heavy metals. Corrosion products obtained from pipes transporting groundwater had higher levels of Br, Ti, Ba, Cu, Sr, V, Cr, La, Pb and As.
Water Research 07/2012; 46(16):5423-33. · 4.86 Impact Factor
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ABSTRACT: Al13 is one of the novel nanospecies in partially neutralized Al(III) solution and Al-OH sol or precipitate could be generated
simultaneously in the neutralization. Unfortunately, the precipitate is believed to be harmful to the formation of Al13 due to the consumption of Al(OH)4
−, which was regarded as the precursor of Al13. In this paper, the feasibility and potential of transformation of freshly formed Al-OH precipitate into Al13 species were studied by using ferron colorimetric method and 27Al NMR spectroscopy. The Al-OH precipitates were produced by two ways: injection of base solution into Al(III) solution gradually
and mixing of Al(III) and base solutions instantaneously. The re-dissolving behaviors of the freshly formed precipitates were
examined under different basicities (OH/Al molar ratio) and temperatures. It has been shown that Al13 could be formed through the re-dissolution of intermediate Al-OH precipitate generated in partially neutralized Al(III) solution.
A possible formation mechanism of Al13 was suggested. Easily transformable precipitate was developed when the OH/Al molar ratio was less than 2.5. Rapid re-dissolution
of freshly formed precipitate was favorable for Al13 formation, which could be enhanced by heating.
Journal of Sol-Gel Science and Technology 04/2012; 41(3):257-265. · 1.63 Impact Factor
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ABSTRACT: The present study aims at investigating the potential impacts of the nC60 complex with atrazine on the development of Japanese medaka (Oryzias latipes) embryos and chronic toxicity to D. magna. Although exposure to nC60 below 8 mg/L had no effects on the hatching rate of medaka embryos, it increased the deformity of hatched larvae. Moreover,
the presence of nC60 significantly increased the hatching time of the embryos exposed to atrazine. 14-day exposure of D. magna to nC60 significantly reduced offspring production even at a concentration as low as 0.5 mg/L. This indicates that nC60 is able to reduce the ability of D. magna to produce offspring, and therefore would have an impact on population. For atrazine, no significant difference in offspring
production was observed. The nC60 complex with atrazine was also found to significantly decrease the reproduction of D. magna, which was similar to the result of exposure to nC60. These results suggest that nC60 would have potential risks to aquatic organisms. Therefore, much attention should be paid to their associations with other
contaminants for fullerene’s risk assessment.
KeywordsFullerenes-complex nanotoxicity-nanoparticles-aquatic organisms
Chinese Science Bulletin 04/2012; 55(4):339-345. · 1.32 Impact Factor
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ABSTRACT: With the widespread application of fullerenes, it is critical to assess their environmental behaviors and their impacts on the transport and bioavailability of organic contaminants. The effects of fullerene particle size, chemistry of the solution, and natural organic matter on the adsorption of atrazine by aqueous dispersions of fullerenes (C(60)) were investigated in this work. The results showed that the Polanyi-Manes model could fit the adsorption isotherms well. Smaller sizes of fullerene particles led to increased available sites and, consequently, enhanced the adsorption of atrazine on C(60). However, intensely dispersed C(60) systems might not possess suitably high adsorptive capacities due to surface chemistry change. Adsorption of atrazine by aqueous dispersions of C(60) increased with a decrease in the pH of the solution. Introduction of humic acid significantly reduced the size of the C(60) particles, and resulted in the increase of the adsorption amount. Fullerene materials, once released into the aquatic environment, are inclined to form aqueous suspensions with different degrees of dispersion, which would greatly affect the transport and fate of organic contaminants.
Environmental Science & Technology 06/2011; 45(14):5959-65. · 4.80 Impact Factor
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ABSTRACT: The aggregation and dispersion behaviors of carbon nanotubes (CNTs) can regulate the environmental spread and fate of CNTs, as well as the organic pollutants adsorbed onto them. In this study, multi-walled carbon nanotubes (MWNTs) and single-walled carbon nanotubes (SWNTs) were surface modified with humic acids from different sources and with surfactants of different ionic types. The dispersion stability of surface modified CNTs was observed by UV-Vis spectrophotometry. The effect of humic acid and surfactant dispersion on the adsorption of atrazine by CNTs was investigated by batch equilibrium experiments. Both humic acid and surfactant could effectively disperse MWNTs, but not SWNTs, into stable suspensions under the studied conditions. Surface modified CNTs had a greatly reduced capacity for adsorption of atrazine. The inhibitory effect of peat humic acid was relatively stronger than that of soil humic acid, but the two surfactants had a similar inhibitory effect on atrazine adsorption by the two CNT types. Increases in surfactant concentration resulted in rapid decreases in the adsorption of atrazine by CNTs when the surfactant concentration was less than 0.5 critical micelle concentration.
Journal of Environmental Sciences 01/2010; 22(8):1195-202. · 1.66 Impact Factor
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ABSTRACT: The fractal dimensions in different topological spaces of polyferric chloride-humic acid (PFC-HA) flocs, formed in flocculating different kinds of humic acids (HA) water at different initial pH (9.0, 7.0, 5.0) and PFC dosages, were calculated by effective density-maximum diameter, image analysis, and N2 absorption-desorption methods, respectively. The mass fractal dimensions (Df) of PFC-HA flocs were calculated by bi-logarithm relation of effective density with maximum diameter and Logan empirical equation. The Df value was more than 2.0 at initial pH of 7.0, which was 11% and 13% higher than those at pH 9.0 and 5.0, respectively, indicating the most compact flocs formed in flocculated HA water at initial pH of 7.0. The image analysis for those flocs indicates that after flocculating the HA water at initial pH greater than 7.0 with PFC flocculant, the fractal dimensions of D2 (logA vs. logdL) and D3 (logVsphere VS. logdL) of PFC-HA flocs decreased with the increase of PFC dosages, and PFC-HA flocs showed a gradually looser structure. At the optimum dosage of PFC, the D2 (logA vs. logdL) values of the flocs show 14%-43% difference with their corresponding Df, and they even had different tendency with the change of initial pH values. However, the D2 values of the flocs formed at three different initial pH in HA solution had a same tendency with the corresponding Dr. Based on fractal Frenkel-Halsey-Hill (FHH) adsorption and desorption equations, the pore surface fractal dimensions (Ds) for dried powders of PFC-HA flocs formed in HA water with initial pH 9.0 and 7.0 were all close to 2.9421, and the Ds values of flocs formed at initial pH 5.0 were less than 2.3746. It indicated that the pore surface fractal dimensions of PFC-HA flocs dried powder mainly show the irregularity from the mesopore-size distribution and marcopore-size distribution.
Journal of Environmental Sciences 02/2009; 21(1):41-8. · 1.66 Impact Factor
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ABSTRACT: Dissolved organic matter (DOM) and its potential to form disinfection by-products (DBPs) during drinking water treatment raise challenges to water quality control. Understanding both chemical and physical characteristics of DOM in source waters is key to better water treatment. In this study, the DOM from four typical source waters in China was fractionated by XAD resin adsorption (RA) and ultrafiltration (UF) techniques. The trihalomethane formation potential (THMFP) of all fractions in the DOM were investigated to reveal the major THM precursors. The fraction distributions of DOM could be related to their geographical origins in a certain extent. The dominant chemical fraction as THM precursors in the DOM from south waters (East-Lake reservoir in Shenzhen and Peal rivers in Guangzhou) was hydrophobic acid (HoA). The size fraction with molecular weight (MW) <1 kDa in both south waters had the highest THMFP. The results of cluster analysis showed that the parameters of fractions including DOC percentage (DOC%), UV254%, SUVA254 (specific UV254 absorbance) and THMFP were better for representing the differences of DOM from the studied waters than specific THMFP (STHMFP). The weak correlation between SUVA254 and STHMFP for either size or XAD fractions suggests that whether SUVA254 can be used as an indicator for the reactivity of THM formation is highly dependent on the nature of organic matter.
Environmental Monitoring and Assessment 06/2008; 141(1-3):347-57. · 1.40 Impact Factor
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ABSTRACT: The powder of polyaluminum chloride-humic acid (PACl-HA) flocs was prepared by cryofixation-vacuum-freeze-drying method. The FTIR spectra show that some characteristic functional groups in polyaluminum chloride (PACl), humic acid (HA), and kaolin still existed in the dried flocs. X-ray diffractometry (XRD) patterns indicate that these flocs are amorphous. Nitrogen adsorption-desorption isotherms were obtained for different samples of the dried PACl-HA flocs. The BET specific surface area, BJH cumulative absorbed volume and BJH desorption average pore diameter of them were determined. The peak values of 8.4-11.2 nm (pore diameter) for pore size distribution (PSD) curves indicate that the pores of the dried flocs are mostly mesopores. The surface fractal dimensions D(s) and the corresponding fractal scales determined from both SEM images and nitrogen adsorption-desorption data sets reveal the multi-scale surface fractal properties of the dried PACl-HA flocs, which exhibited two distinct fractal regimes: a regime of low fractal dimensions (2.07-2.26) at higher scales (23-387 nm), mainly belonging to exterior surface scales, and a higher fractal dimensions (2.24-2.37) at lower scales (0.80-7.81 nm), falling in pore surface scales. Both HA addition and kaolin reduction in dried floc can decrease the irregularity and roughness of external surface. However, for the irregularity and roughness of pore surface, the addition of HA or kaolin in dried floc can increase them. Furthermore, some difference was found between the pore surface fractal dimensions D(s) calculated from nitrogen adsorption and desorption data. The pore surface D(s) values calculated through thermodynamic model were much greater than three.
Journal of Colloid and Interface Science 01/2008; 316(2):457-66. · 3.07 Impact Factor
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ABSTRACT: Although ozone is widely used as a pre-oxidant before coagulation in water treatment, the effect of pre-ozonation on optimized coagulation for removal of particle and natural organic matter (NOM) is still not fully understood. In this paper, pilot-scale investigation was conducted to examine the impact of pre-ozonation on coagulation for particle and NOM removal. Changes in the particle and NOM distributions were characterized by various methods, including laser light granularity system, particle counter, ultrafiltration, and resin absorbent fractionation. A novel composite flocculant-HPAC was compared with the traditional ferric chloride coagulant in terms of coagulation efficiency under the influence of pre-ozonation. Typical micro-polluted North China surface water was used for pilot coagulation tests. The results show that the effect of pre-ozonation on coagulation is associated with the dosage of ozone, coagulant type, and water contamination characteristics. For FeCl(3), pre-ozonation acts as a coagulation aid at low dosage (1.0 mg L(-1) O(3)) for turbidity and UV(254) removal; while at higher dosage (2.0 mg L(-1) O(3)), pre-ozonation is detrimental to UV(254) removal although it is still beneficial for turbidity removal. In the case of composite flocculant-HPAC, pre-ozonation demonstrates negligible influence on both turbidity and UV(254) removal. Ozone can simultaneously aggregate fine particles and break down large ones, making them more mineralized and easier to remove. NOM with intermediate molecular weight and hydrophobic neutral property increases at lower ozone dosage, favoring removal by coagulation. At higher ozone dosages, NOM becomes more hydrophilic and its molecular weight becomes smaller, decreasing NOM removal.
Chemosphere 12/2007; 69(11):1695-702. · 3.21 Impact Factor
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ABSTRACT: A large-scale pilot study was carried out to evaluate the impacts of changes in water source and treatment process on iron and copper release in water distribution systems. Finished surface waters, groundwaters, and desalinated waters were produced with seven different treatment systems and supplied to 18 pipe distribution systems (PDSs). The major water treatment processes included lime softening, ferric sulfate coagulation, reverse osmosis, nanofiltration, and integrated membrane systems. PDSs were constructed from PVC, lined cast iron, unlined cast iron, and galvanized pipes. Copper pipe loops were set up for corrosion monitoring. Results showed that surface water after ferric sulfate coagulation had low alkalinity and high sulfates, and consequently caused the highest iron release. Finished groundwater treated by conventional method produced the lowest iron release but the highest copper release. The iron release of desalinated water was relatively high because of the water's high chloride level and low alkalinity. Both iron and copper release behaviors were influenced by temperature.
Journal of environmental health 10/2007; 70(2):29-36, 44, 46. · 0.80 Impact Factor
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ABSTRACT: Removal of three direct dyes (Direct Black 19, Direct Red 28, and Direct Blue 86) by coagulation with three different Al based coagulants was investigated. The main purpose of this paper is to examine the coagulation features of polymeric aluminum coagulants in treatment of dye-polluted waters and the emphasis was placed on the roles of preformed Al species, particularly Al(13). The performance of Al(13) in coagulation of dyes was observed through jar tests by comparing traditional Al salt, polyaluminum chloride (PACl), and purified Al(13). The results showed that under most cases Al(13) had significantly higher efficiency in removal of direct dyes than traditional Al salt and commercial PACl with the exception of Direct Red 28 removal under high pH range. The coagulation of direct dyes could be greatly affected by pH. Reducing pH was favorable for preformed Al species in a broad pH range. For traditional Al coagulant, efficient dye removal only occurred in a relatively narrow pH range of near 6.0. The outstanding coagulation behavior of Al(13) could be ascribed to its high charge neutralization ability, relative stability and potential self-assembly tendency.
Journal of Hazardous Materials 06/2007; 143(1-2):567-74. · 4.17 Impact Factor
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ABSTRACT: A pilot study was conducted to assess the effect of water quality changes on iron and copper release in distribution systems. Three finished waters were prepared from groundwater source by conventional treatment, lime softening and reverse osmosis (RO). To mimic desalinated seawater, sea salts were added to RO treated water. Both lime softening and RO treatment significantly decreased the calcium concentration and alkalinity of groundwater. During a yearlong investigation, the impact of seasonal changes on iron and copper release was also evaluated. The results showed that groundwater after lime softening slightly increased iron release potential but significantly decreased copper release. Desalination water caused much higher iron release but lower copper release than conventionally treated groundwater. Blended water with conventional groundwater and desalination water resulted in intermediate iron release but much high copper release. Both iron and copper release could be accelerated by temperature increase.
Journal of Environmental Science and Health Part A 02/2006; 41(8):1667-83. · 1.19 Impact Factor
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ABSTRACT: With the development of nanotechnologies, a large number of nano-materials with novel properties are being released into the environment. However, little is known about their fate, transport, toxicity and interactions with organic matters in aqueous environment. In this study, nano-SiO2 or kaolinite, coated with soil humic acid (SHA) and peat humic acid (PHA), were used as sorbents. The original and HA-coated nanoparticles were characterized for particle size, TEM and electrophoretic mobility. Sequential ultrafiltration (UF) was used to characterize the molecular size fractionations of dissolved HAs. Sorption data of atrazine (AT) under various solution concentration, ionic strength and pH were well fitted with Freundlich model. Sorption amount of AT on HA-coated nanoparticles was significantly lower than that on original particles. The sorption maximum appeared at I = 0.001 mol/l (NaNO3), pH 3. Size of nanoparticle aggregates, conformation of HA and specific surface area were factors affecting the sorption process. The compressed conformation of HA was more favorable for HA sorption than expanded one. Size of aggregation was not a determinant factor for the sorption process, while the specific surface areas of nano-sorbent was an important one. Results indicated that HA plays an important role in the transport and toxicity of nanoparticles and AT in aqueous environment.
Colloids and Surfaces A: Physicochemical and Engineering Aspects.
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ABSTRACT: The coagulation behavior of polyaluminum chloride (PACl) with various basicities (B = OH/Al values) was investigated under different alkalinities. It is aimed to get better insights into the coagulation mechanisms involving interactions between hydrolyzed Al(III) products and particles. Jar tests were used to evaluate the coagulation efficiencies, including zeta potentials, residual turbidities (RT) and pH values. An optical monitoring technique of photometric dispersion analyzer (PDA) was utilized to observe the coagulation dynamics. The experimental results show that the traditional coagulant such as alum evolves a rapid hydrolysis after dosing and the in situ formed hydrolysis products can destabilize the kaolin particles by precipitation charge neutralization (PCN). The preformed polymeric species in PACls exhibit a relatively high stability after dosing and can form “electrostatic patches” on clay particle surfaces. These patches play a crucial role in “electrostatic patch coagulation” (EPC). Increasing alkalinity extends both PCN and EPC zones. Under the low alkalinity, EPC with high Alb contained in PACls works better than PCN coagulation; increased alkalinity improves the efficiency of traditional coagulant due to sweep flocculation. Under the higher alkalinity, more coagulant is required to achieve complete charge neutralization. The stoichiometric relationships between the dosage and alkalinity are different depending on the B values of PACls.
Colloids and Surfaces A: Physicochemical and Engineering Aspects.
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ABSTRACT: Urea hydrolysis has always been used to prepare alumina gels and little attention has been paid to the reactive polymeric Al species that is formed before alumina sol–gels occur. Based on the hydrolysis process of aluminum in urea solution at 90 °C, speciation and transformation of the reactive hydroxyl-Al polymers obtained by urea hydrolysis was investigated with Ferron assay, solution-state and solid-state 27Al NMR spectroscopy. Unlike the traditional viewpoint, Keggin-Al13 can form in solution without localized high alkalinity. The reaction of oligomers with Al(OH)4− resulted from the dissolving of colloidal Al hydroxides is accountable for the formation of Keggin-Al13. Alp1, the defected structure of Al13, was considered as the transient species in the transformation from Al13 to crystalline Al hydroxides. Besides Al13, some other reactive polymers with hexameric ring structure also exist. The two categories of Al species have different transformation models (i.e., forced hydrolysis and spontaneous hydrolysis). The forced hydrolysis model should be the main transformation pattern for Al species under the condition of strong base addition into Al solution. Sulphate ions inhibit the formation of high polymeric Al species and affect the crystal structure of the final Al precipitate.
Colloids and Surfaces A: Physicochemical and Engineering Aspects.
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ABSTRACT: As an effective disinfection by-product control strategy, enhanced coagulation has been being widely used for surface water treatment. In this paper, the influences of adopting enhanced coagulation on possible water quality changes in distribution system were evaluated through a long-term field investigation using pilot water treatment and distribution systems. The finished waters were produced by different post-treatments following enhanced coagulation: ozonation combined with biologically activated carbon filtration and membrane nanofiltration. The pilot distribution systems were constructed using old pipes of four different materials including PVC, lined and unlined iron pipes as well as galvanized steel pipes. Copper loops were also set up for monitoring lead and copper corrosion compliances. A yearlong investigation revealed that reduced alkalinity and increased salinity resulted from enhanced coagulation could cause severe iron release and heavy discolored water, but such water quality changes did not increase copper corrosivity. The copper corrosion by-product release was primarily affected by alkalinity and also sensitive to pH variations. Membrane desalination together with alkalinity adjustment mitigated the iron release significantly. Iron release could be accelerated by high temperature.
Desalination.
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ABSTRACT: Inorganic polymeric Al coagulants have been being widely used in water treatment due to their advantages of applicability within broad pH and temperature ranges, high capacity of charge neutralization as well as less alkalinity consumption. However, the removal of dissolved organic matter (DOM) by such kind of coagulants has not been well understood because of the complexity of natural organic matter and the diversity of such polymeric Al coagulants. In this paper, coagulants with different Al speciation characteristics were prepared to conduct coagulation of humic acid (HA). The humic acid used was peat origin and was characterized physicochemically. The results showed that coagulants with preformed Al species were less effective than conventional Al salt in removing humic acid with large molecular and hydrophobic properties. The flocs formed by preformed Al species were smaller than those formed by conventional Al salt. Decreasing pH could improve the coagulation performance of all coagulants. Coagulation of humic acid might not follow the same charge neutralization rules associated with coagulation of mineral colloids. In the presence of humic acid, Al13 could be decomposed during coagulation process.
Colloids and Surfaces A: Physicochemical and Engineering Aspects.
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ABSTRACT: Nitrogen absorption–desorption isotherms were obtained on different natural particles around Guanting reservoir, and their data points were used to analyze the pore structure and fractal properties of the obtained solids. Other microstructure parameters of these particles are the following: 9.5669–4.5605 m2 g−1 of BET specific surface area, 0.01784–0.06656 cm3 g−1 of BJH cumulative absorbed volume and 7.20–7.74 nm of BJH desorption average pore diameter. The peak values of pore size distribution (PSD) curves were found at near 3.74 nm for samples 2, 3 and 4, and near 3.25 nm for sample 1, and near 5.17 nm for sample 5. The average pore diameter was larger than that corresponding to the peak value of pore size distribution (PSD). The micropore areas are very small in these particles, but their micropore volume of them can occupy over 15% of total pore volume.The self-similar and rough surface was observed on these particles, and the pore surface fractal dimensions Ds of them were between 2.69 and 2.80, calculated by fractal FHH equation with the data of the adsorption branch of the isotherm, are a little difference from ones with the isotherm data of desorption branch, and also their corresponding fractal scales are different. It may be attributed to the different p/p0 range for Ds values calculation and pore structure property. Otherwise, the computing Ds values by thermodynamic model do not give meaningful indication for particle surface irregularity.There are about 1–2 specific surface sites (DOH) in each square nanometers on these particles surface, and at most pH range, the average number of protons reacted per surface site (Z) have negative values, and only when pH values are lower than about 4, Z can have positive values. Potentiometric titration experiment and two surface complexation model simulation results indicate that CCM simulation results can better interpret the experiment data points than DLM at 0.005 mol L−1 ion strength. Based on the CCM, the protonation and deprotonation reactions model can successfully depicted the acid–base behavior of natural particles surface, and the surface intrinsic acidic constants and the total concentration of surface sites for these natural particles, could be obtained.
Colloids and Surfaces A Physicochemical and Engineering Aspects 307:16-27. · 2.24 Impact Factor
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ABSTRACT: The isothermic and kinetic adsorption processes of three dyes onto granular activated carbon (GAC) were studied in this paper. Langmuir fractal equation was chosen to fit the adsorption isotherm data. The exponent m in the equation is a function of surface fractal dimension (Ds) of particles and cross-section area (α0) or radius (r0) of dye molecules, which can be approximately estimated according to the relation between the first order term of molecular connective index 1χ and the total surface molecular area (TSA). Based on the modeling results, Ds of the GAC was estimated to be 2.59, indicating the fractal adsorption characteristics of GAC.To elucidate the adsorption kinetics of complex molecules onto fractal surfaces, the relationships of m, kinetic parameter h and fractal spectral dimension (ds) were developed, and the derivative relation of ds and surface fractal dimension Ds was achieved. Adsorption kinetic results showed that the kinetic process had fractal-like characteristics. The instantaneous rate coefficient exhibited power-law relation with reaction time. Although h was larger than one in this study, both the fractal spectral dimension (ds) and the order of reaction could be obtained, and the corresponding ds values were less than two. The effective reaction order x was related to ds, Ds and adsorbate concentration, and it was found that the order of diffusion-controlled adsorption reaction was fractional in most cases. The h or ds values calculated here implied that the reciprocating shake was not always effective to eliminate the dimensional constraints.
Colloids and Surfaces A Physicochemical and Engineering Aspects 299:224-231. · 2.24 Impact Factor
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ABSTRACT: A methodology of preparing high purity Al13 through chemical precipitation/separation was developed. Polyaluminum chloride (PACl) with medium high concentration (0.1–1.1 mol/L as Al) was used as the source of Al13. The factors that affect separation process were thoroughly examined. Intermediate and final products of Al13 were characterized morphologically and structurally using SEM, XRD, and solid-state 27Al NMR. The purity of obtained Al13 product was verified using both ferron assay and 27Al NMR. It was found that the separation of Al13 from medium high concentration PACl was feasible and the purity of Al13 product could be higher than 95%.
Separation and Purification Technology 54(1):88-95. · 2.92 Impact Factor
