Co-reporter:Ling Yang;Di An;Boyang Liu
Industrial & Engineering Chemistry Research May 4, 2016 Volume 55(Issue 17) pp:4803-4810
Publication Date(Web):Publication Date (Web): April 8, 2016
DOI:10.1021/acs.iecr.6b00620
Graphene oxide (GO) is a type of two-dimensional nanomaterial with a single-atom thickness. GO sheets contain pristine regions, oxidized regions, and a small fraction of holes. By stacking GO sheets together, a GO membrane can be fabricated with sufficient mechanical strength. The interlayer nanocapillary network formed from connected interlayer spaces, together with the gaps between the edges of noninterlocked neighboring GO sheets and cracks or holes of the GO sheet, provides passage for molecules or ions to permeate through the GO membrane in an aqueous solution. The characteristics of molecules or ions (e.g., their size, charge, and the interaction with the GO membrane) affect the separation performance of the GO membrane. The contribution of gaps between neighboring GO sheets for separation can be adjusted by changing the GO sheet size and the GO membrane thickness. The interlayer space of the GO membrane can be adjusted by changing the water pH and modifying or reducing the GO sheets to obtain the desired separation performance. The production of the GO membrane is easily scalable and relatively inexpensive, indicating that the GO membrane has promising potential for applications such as water treatment, desalination, anticorrosion, chemical resistance, and controlled release coatings.
Co-reporter:Di An, Ling Yang, Boyang Liu, Ting-Jie Wang, and Chengyou Kan
Journal of Agricultural and Food Chemistry December 20, 2017 Volume 65(Issue 50) pp:10868-10868
Publication Date(Web):November 27, 2017
DOI:10.1021/acs.jafc.7b04225
Matching the nutrient release rate of coated fertilizer with the nutrient uptake rate of the crop is the best way to increase the utilization efficiency of nutrients and reduce environmental pollution from the fertilizer. The diffusion property and mechanism of nutrients through the film are the theoretical basis for the product pattern design of coated fertilizers. For the coated fertilizer with a single-component nutrient, an extended solution–diffusion model was used to describe the difference of nutrient release rate, and the release rate is proportional to the permeation coefficient and the solubility of the nutrient. For the double- and triple-component fertilizer of N–K, N–P, and N–P–K, because of the interaction among nutrient molecules and ions, the release rates of different nutrients were significantly affected by the components in the composite fertilizer. Coating the single-component fertilizer (i.e., nitrogen fertilizer, phosphate fertilizer, and potash fertilizer) first and subsequently bulk blending is expected to be a promising way to adjust flexibly the nutrient release rate to meet the nutrient uptake rate of the crop.Keywords: coated fertilizer; controlled release; diffusion; nutrient; polymer latex;
Co-reporter:Yingzhen Li, Yanping Jiang, Ting-Jie Wang, Chang Zhang, Haifeng Wang
Separation and Purification Technology 2017 Volume 172() pp:415-421
Publication Date(Web):1 January 2017
DOI:10.1016/j.seppur.2016.08.043
•Electrosorption process for fluoride removal was developed.•Micropore-dominant AC enables the electrode to achieve high charge efficiency.•The saturated electrosorption capacity for fluoride reached 16.8 mg/g.•The electrodes are easily regenerated by shorting without secondary pollution.•The capacity has a linear relationship to the square of the applied voltage.Fluoride electrosorption using micropore-dominant activated carbon (AC) as an electrode was developed. The parameters of voltage, flow rate, and electrode gap were optimized to be 1.6 V, 10 mL/min and 2 mm, respectively. The electrosorption isotherm conforms to the Langmuir model, indicating the monolayer adsorption of the fluoride ions. The saturated electrosorption capacity for fluoride ions under the optimized parameters was 16.8 mg/g (AC). The high saturated electrosorption capacity of this micropore-dominant AC was attributed to its high specific surface area of 2130 m2/g, which was mainly contributed by the micropores. The saturated electrosorption capacity has a linear relationship to the square of the applied voltage. The fluoride electrosorption occurred only when the voltage was higher than the electro-capillary maximum voltage of 0.14 V for this AC. The charge efficiency reached a high value of 0.98 for the micropore-dominant AC, indicating that only counterions existed in the micropores.
Co-reporter:Di An, Boyang Liu, Ling Yang, Ting-Jie Wang, Chengyou Kan
Chemical Engineering Journal 2017 Volume 311(Volume 311) pp:
Publication Date(Web):1 March 2017
DOI:10.1016/j.cej.2016.11.109
•Composite film was coated on KNO3 fertilizer via spray coating in a fluidized bed.•GO membrane formed from GO sheets coated each KNO3 granule completely.•Composition of GO membrane in polymer film extended release duration of coated KNO3.•Long diffusion path & slow diffusion rate for K+ & NO3− give long release duration.The application of a polymer film coated fertilizer can increase nutrient utilization efficiency and reduce environmental pollution, and polymer latex is an environmental friendly coating material with a promising future. However, because of the hydrophilicity of the film formed from polymer latex, it is difficult to achieve film coated fertilizer with a long release duration and a low consumption of the coating materials. Through spray coating in a fluidized bed, the sandwich structure of a composite film, i.e., polymer film/graphene oxide membrane/polymer film, was coated on KNO3 granules. Because of the longer diffusion path for the hydrated K+ and NO3− diffusing within the graphene oxide membrane and the slower diffusion rate caused by cation-π interactions between the hydrated K+ and graphene oxide, the release duration of the film coated KNO3 fertilizer was extended. For the pure polymer film coated KNO3 granules, the release duration was 24 days, while the release durations of the composite film coated KNO3 granules were extended to 26, 29, 34 and 38 days when the amounts of graphene oxide in the coating were 0.18%, 0.72%, 1.43% and 2.86% of the film, respectively. It is shown that graphene oxide has great potential in applications in the field of controlled release fertilizers.Download high-res image (178KB)Download full-size image
Co-reporter:Chang Zhang, Yingzhen Li, Ting-Jie Wang, Yanping Jiang, Jason Fok
Applied Surface Science 2017 Volume 425(Volume 425) pp:
Publication Date(Web):15 December 2017
DOI:10.1016/j.apsusc.2017.06.159
•A high-capacity iron oxide adsorbent with low cost was prepared.•Ethanol treatment changed adsorbent microstructure and inhibited crystallization.•Ethanol treatment increased surface area and adsorption capacity significantly.•Adsorption occurred by exchange of F− with OH− groups on adsorbent surface.•Achieved high F− adsorption in wide pH range and in the presence of co-anions.A novel iron oxide adsorbent with a high fluoride adsorption capacity was prepared by a facile wet-chemical precipitation method and ethanol treatment. The ethanol-treated adsorbent was amorphous and had a high specific surface area. The adsorption capacity of the treated adsorbent was much higher than that of untreated adsorbent. The Langmuir maximum adsorption capacity of the adsorbent prepared at a low final precipitation pH (≤9.0) and treated with ethanol reached 60.8 mg/g. A fast adsorption rate was obtained, and 80% of the adsorption equilibrium capacity was achieved within 2 min. The adsorbent had high fluoride-removal efficiency for water in a wide initial pH range of 3.5–10.3 and had a high affinity for fluoride in the presence of common co-anions. The ethanol treatment resulted in structure transformation of the adsorbent by inhibiting the crystallization of the nano-precipitates. The adsorption was confirmed to be ion exchange between fluoride ions and the hydroxyl groups on the adsorbent surface.Download high-res image (113KB)Download full-size image
Co-reporter:Yong Liang, Keyi Yu, Jiuren Xie, Qinzhong Zheng, Ting-Jie Wang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2017 Volume 520(Volume 520) pp:
Publication Date(Web):5 May 2017
DOI:10.1016/j.colsurfa.2017.02.046
•TiO2@void@SiO2structurewaspreparedbysurface-protectedetching.•The void in the yolk-shell structure increased the refractive index difference.•TiO2@void@SiO2 has high hiding power and low weather durability.•TiO2@MgO@void@SiO2 was prepared to increase weather durability.•TiO2@MgO@void@SiO2 structure saves TiO2 consumption 21.2%.High hiding power and weather durability are the key characteristic indices of the high-performance pigmentary titanium dioxide (TiO2). The film-coated TiO2 particles with a yolk-shell structure of silica were prepared by surface-protected etching with polyvinyl pyrrolidone. The hiding power of the TiO2 particles with the yolk-shell structure was 90.6, which is significantly higher than the hiding power of 87.7 for the dense film-coated TiO2 particles with the same amount of coating (20%). However, the TiO2 particles with the yolk-shell structure have low weather durability. The apparent degradation rate constant Kapp for rhodamine-B had a high value of 13.2. An improvement was made by coating a dense MgO film on the TiO2 particles first, and then coating a yolk-shell structure. The hiding power of the TiO2 particles with the improved yolk-shell structure reached 90.6, and the weather durability was significantly increased as the apparent degradation rate constant Kapp decreased to 2.2, reaching the excellent weather durability of the TiO2 particles with 5 wt% dense film coating (Si3 + Al2), which is a common product in industry (Kapp = 1.8). For the same indices of hiding power and weather durability, the TiO2 particles with the improved yolk-shell structure obviously decreased the consumption of TiO2, compared with the dense SiO2-coated TiO2 particles (TiO2@SiO2). It is inferred that the void in the yolk-shell structure increased the light reflectivity of the TiO2 particles by increasing the difference of the refractive index between the core TiO2 and the surroundings, and the dense MgO film increased the weather durability of the TiO2 particles.Download high-res image (136KB)Download full-size imageYolk-shell TiO2@MgO@void@SiO2 pigment exhibited high hiding power and weather durability. Compared with the same coating amount of 20% in dense film, the consumption of coated TiO2 is reduced over 20%.
Co-reporter:Chang Zhang, Yingzhen Li, Yanping Jiang, and Ting-Jie Wang
Industrial & Engineering Chemistry Research 2017 Volume 56(Issue 9) pp:
Publication Date(Web):February 14, 2017
DOI:10.1021/acs.iecr.6b03856
A magnetic Fe3O4@Fe–Ti composite nanoadsorbent was aggregated to micrometer size for high-efficiency fluoride removal and effective separation of the adsorbent from the water after defluoridation. The adsorption and separation performances of the micrometer-sized adsorbent were investigated. The granular adsorbent at an aggregated size of approximately 10 μm had little intragranule diffusion resistance. This granule adsorbent was easily separated from water using magnetic separation after defluoridation. The thermal treatment at the best temperature, 200 °C, increased the granular strength without causing the undesired effects of magnetization decrease and crystallinity increase. For the adsorbent granules with an average size of 11 μm that were heated at 200 °C for 1.5 h, the fluoride adsorption was completely achieved within only 2 min in a novel defluoridation process with a fluidized bed, and over 99% of the adsorbent was intercepted by using a magnetic separation unit. After a simple ultrafiltration unit, no adsorbent residue was detected in the outlet water, guaranteeing the safety of the drinking water. Compared with a traditional fixed-bed process, the fluidized-bed process in this work has the advantages of high defluoridation rate, small apparatus size, high security, and suitability for household utilization.
Co-reporter:Bing Qiao, Yong Liang, Ting-Jie Wang, Yanping Jiang
Applied Surface Science 2016 Volume 364() pp:103-109
Publication Date(Web):28 February 2016
DOI:10.1016/j.apsusc.2015.12.116
Highlights
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Silica was modified to produce hydrophobic surface using SDS as modifier.
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The route is free of organic solvent and gets perfect contact of SDS and silica.
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Contact angle of modified silica particles reached 107°.
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Grafted density on the silica surface reached 1.82 SDS nm−2.
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Brønsted acid sites supply proton to react with SDS via generating carbocation.
Co-reporter:Chang Zhang, Yingzhen Li, Ting-Jie Wang, Yanping Jiang, Haifeng Wang
Applied Surface Science 2016 Volume 363() pp:507-515
Publication Date(Web):15 February 2016
DOI:10.1016/j.apsusc.2015.12.071
Highlights
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A micron-sized magnetic adsorbent (MMA) with high separability was prepared.
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MMA had high adsorption capacity and high selectivity for fluoride.
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MMA had high fluoride removal efficiency in a wide pH range.
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Abundant surface hydroxyl of MMA contributed to high affinity for fluoride.
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Both adsorption and regeneration can reach equilibrium within 2 min.
Co-reporter:Yong Liang, Bing Qiao, Tig-Jie Wang, Han Gao, Keyi Yu
Applied Surface Science 2016 Volume 387() pp:581-587
Publication Date(Web):30 November 2016
DOI:10.1016/j.apsusc.2016.06.131
Highlights
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Light reflectivity of coated films was calculated using a plane film model.
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Film reflectivity decreases as the refractive index increases from 1.00 to 2.15.
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Porous films achieved by triethanolamine addition and subsequent calcination.
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Porous films on TiO2 particles increased the hiding power from 88.3 to 90.8.
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The required TiO2 particle dosage was reduced by ∼10% by using porous films.
Co-reporter:Bing Qiao, Ting-Jie Wang, Han Gao, Yong Jin
Applied Surface Science 2015 Volume 351() pp:646-654
Publication Date(Web):1 October 2015
DOI:10.1016/j.apsusc.2015.05.174
Highlights
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Developed a novel and efficient process for nano-silica particle modification.
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The stages of aqueous mixing, spray drying and thermal treatment were combined.
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After each stage, the APTES grafting conversions were 25.3%, 50.7% and 80.6%.
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High density of 13.48 APTES nm−2 was silanized on the silica particle surface.
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Reaction of APTES on silica surface was reversible in the thermal treatment.
Co-reporter:Chang Zhang, Lin Chen, Ting-Jie Wang, Chao-Li Su, Yong Jin
Applied Surface Science 2014 Volume 317() pp:552-559
Publication Date(Web):30 October 2014
DOI:10.1016/j.apsusc.2014.08.143
Highlights
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Fe–Ti/Fe3O4 adsorbent was prepared for rapid adsorption and complete separation.
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The Fe–Ti/Fe3O4 composite nano-adsorbent has a core–shell structure.
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Magnetic composite nano-adsorbent was easily separated from water solution.
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Composite nano-adsorbent can be used in fluidized systems for fluoride adsorption.
Co-reporter:Han Gao, Bing Qiao, Ting-Jie Wang, Dezheng Wang, and Yong Jin
Industrial & Engineering Chemistry Research 2014 Volume 53(Issue 1) pp:189-197
Publication Date(Web):2017-2-22
DOI:10.1021/ie402539n
The use of cerium oxide coating of titanium dioxide pigments to decrease photocatalytic activity was studied. A large decrease in the photocatalytic activity of titanium dioxide particles coated with cerium oxide was obtained even with a tiny coating amount of 0.2 wt %, and these particles were more stable than those with the conventional 2.0 wt % film coating of silicon dioxide or 1.5 wt % aluminum oxide. The combination film coatings of cerium oxide and silicon or aluminum oxide showed smaller decreases in photocatalytic activity. Both Ce(III) and Ce(IV) oxide coatings gave highly decreased photocatalytic activity, even when the cerium oxide coating did not completely cover the surface. It was inferred that the efficient decrease of photocatalytic activity was because the unpaired electrons in the 4f orbital of cerium enabled the coating film to capture electrons and holes that were produced when titanium dioxide was exposed to ultraviolet irradiation.
Co-reporter:R. Lan;G. Wang;L. Yang;T.-J. Wang;C. Kan ;Y. Jin
Chemical Engineering & Technology 2013 Volume 36( Issue 2) pp:347-354
Publication Date(Web):
DOI:10.1002/ceat.201200459
Abstract
An efficient method for the prediction of the release characteristics of film-coated urea from its film structure is proposed. A model spray-coating apparatus was built to prepare a plane film to directly measure the film permeability coefficients by simulating the characteristics of randomness, intermittence and multiple layers of the coating, and eliminating particle collision effects. From analysis, the spray-coated film structure can be modeled as comprising a dense structure and a defect structure. Both structures contributed to the penetration flux and the apparent permeability coefficients of the film for water and urea diffusion. The permeability coefficients of the plane films were calculated from the film structure model, and were shown to be close to the measured values.
Co-reporter:Bing-Xin Wei, Lin Zhao, Ting-Jie Wang, Han Gao, Hai-Xia Wu, Yong Jin
Advanced Powder Technology 2013 Volume 24(Issue 3) pp:708-713
Publication Date(Web):May 2013
DOI:10.1016/j.apt.2012.12.009
Abstract
Titanium dioxide is the best white pigment, but it does not have good photo-stability if it is not properly coated. As a change from the conventional coating with silicon or aluminum oxide, its photo-stability after coating with zirconium, cerium as well as some other transition metal oxides was investigated. The function of the coated film was to capture electrons and holes of the TiO2 particles produced by the ultraviolet irradiation that otherwise could produce free radicals on the TiO2 surface. A new more efficient, easier and more accurate method that used rhodamine-B degradation was used to evaluate the photo-stability of the coated TiO2 particles. TiO2 particles coated with the oxides of zirconium, cerium, cobalt or nickel had excellent weather durability, even with only a small amount of coating.
Co-reporter:Guanda Wang, Ling Yang, Rui Lan, Tingjie Wang, Yong Jin
Particuology 2013 Volume 11(Issue 5) pp:483-489
Publication Date(Web):October 2013
DOI:10.1016/j.partic.2012.10.005
Spherical 2–4 mm granules of ammonium sulfate (NH4)2SO4 are promising fertilizer for practical use, though only much smaller grains are being produced in industry. This work used coating granulation to produce large spherical granules of (NH4)2SO4 in a fluidized bed by spraying its aqueous solution onto 0.9–1.6 mm (NH4)2SO4 core particles. However, the overall coating efficiency was only 58% due to loss as dust by attrition of (NH4)2SO4 in the vent gas. By adding CaCO3 or SiO2 particles into the feed solution, the coating efficiency was increased to over 90%. This increase in coating efficiency was due to a change in the crystallization mechanism of (NH4)2SO4. The added CaCO3 or SiO2 particles provided a heterogeneous surface that induced (NH4)2SO4 to crystallize uniformly to form a more compact structure less susceptible to attrition.Graphical abstractHighlights► High efficiency of (NH4)2SO4 aqueous solution coating granulation was achieved. ► Sand-like structure in the granules of pure (NH4)2SO4 was found. ► Compact structure of granules was achieved by adding CaCO3 or SiO2 additives. ► Granules with higher strength were produced from heterogeneous crystallization.
Co-reporter:Lin Chen, Bo-Yang He, Shuai He, Ting-Jie Wang, Chao-Li Su, Yong Jin
Powder Technology 2012 Volume 227() pp:3-8
Publication Date(Web):September 2012
DOI:10.1016/j.powtec.2011.11.030
A novel bimetallic oxide adsorbent was synthesized by the co-precipitation of Fe(II) and Ti(IV) sulfate solution using ammonia titration at room temperature. The influences of the washing and drying methods, Fe/Ti molar ratio, and calcination temperature used in the preparation on the morphology, crystallization, surface structure and adsorption capacity were investigated. An optimized Fe―Ti adsorbent had a Langmuir adsorption capacity of 47.0 mg/g, which was much higher than that of either a pure Fe oxide or Ti oxide adsorbent. There was a synergistic interaction between Fe and Ti in which Fe―O―Ti bonds on the adsorbent surface and hydroxyl groups provide the active sites for adsorption, and Fe―O―Ti―F bonds were formed by fluoride adsorption. The novel Fe―Ti adsorbent is efficient and economical for fluoride removal from drinking water.A novel Fe―Ti oxide nano-adsorbent was synthesized by co-precipitation, which had a Langmuir adsorption capacity of 47.0 mg/g at optimized condition. The Fe―O―Ti bond in the Fe―Ti adsorbent supported the active site (Fe―O―Ti―OH) for fluoride adsorption by forming a Fe―O―Ti―F bond on the adsorbent surface.Highlights► A novel and costless Fe―Ti oxide nano-adsorbent was synthesized. ► The optimized Fe―Ti adsorbent had a Langmuir adsorption capacity of 47.0 mg/g. ► Fe and Ti in the adsorbent showed a remarkable synergistic interaction. ► The formed Fe―O―Ti in Fe―Ti adsorbent provided active sites of Fe―O―Ti―OH.
Co-reporter:Lin Chen, Shuai He, Bo-Yang He, Ting-Jie Wang, Chao-Li Su, Chang Zhang, and Yong Jin
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 40) pp:13150
Publication Date(Web):September 13, 2012
DOI:10.1021/ie300102v
A novel iron-doped titanium oxide adsorbent was synthesized by precipitation from a solution of Ti(SO4)2 and FeSO4 and used for fluoride removal from drinking water. The effects of the final pH of the precipitation solution on the adsorbent structure were investigated, and optimized conditions for the synthesis were obtained. The iron doped into the titanium oxide increased the amount of active hydroxyl groups on the adsorbent surface, which increased the fluoride adsorption capacity. The optimized adsorbent had an adsorption capacity of 53.22 mg/g, obtained by fitting adsorption data to the Langmuir isotherm. The adsorption of fluoride followed second-order kinetics. The initial pH of the fluoride solution had little effect on the adsorption capacity. A thermodynamics analysis showed that the adsorption of fluoride ions onto the adsorbent was spontaneous. The adsorbent was easily regenerated with an alkali solution.
Co-reporter:Bing-Xin Wei, Lin Zhao, Ting-Jie Wang, and Yong Jin
Industrial & Engineering Chemistry Research 2011 Volume 50(Issue 24) pp:13799-13804
Publication Date(Web):September 27, 2011
DOI:10.1021/ie201233u
A SiO2–Al2O3 double layer coating process is widely used for TiO2 particle to reduce its photocatalytic activity. The conventional coating process needs a long time and uses large amounts of acid and alkali solutions. We recently developed a new SiO2–Al2O3 composite coating process that needs less time and does not use acid and alkali solutions. This process produced coated TiO2 particles with excellent weather durability, but it had the problem that the filter cakes composed of these particles were thixotropically thin and were easily broken up by shear or disturbance on a conveyor belt; that is, the cakes thinned into slurries very quickly. A slurry is not a suitable physical form for the subsequent drying process in industrial production. To understand this problem better, the rheology of the filter cakes was measured. Experiments to investigate the mechanism of the thixotropic thinning behavior indicated that the Si–O–H groups on the surface of the coated particles formed, by hydrogen bonding, a network structure of the particles that entrapped water within the structure. This structure was easily destroyed by an applied shear or disturbance, leading to the release of the occluded water, and the presence of water caused the cake to become a slurry and its viscosity to decrease sharply. This thixotropic thinning behavior of the filter cake was eliminated by coating the particle surface with a thin film of aluminum oxide.
Co-reporter:Hai-Xia Wu, Ting-Jie Wang, Lin Chen, Yong Jin, Yu Zhang, Xiao-Min Dou
Powder Technology 2011 Volume 209(1–3) pp:92-97
Publication Date(Web):15 May 2011
DOI:10.1016/j.powtec.2011.02.013
Nano-adsorbents of Fe–Al–Ce trimetal hydroxide (FAC) were immobilized in porous polyvinyl alcohol (PVA) via cross-linking with boric acid. Spherical composite granules of 3–5 mm in size that would not cause a large pressure drop in a packed bed were obtained. SEM images showed that the FAC particles were embedded in holes of about 10 μm in the PVA granules, while the surface pores of the granules were only nano-scale in size. Thermal analysis showed that the FAC and PVA in the granules combined tightly by forming a chemical bond. The mechanical stability of the granules decreased with increased FAC concentration, and increased with increased PVA concentration. The fluoride adsorption capacity of the granules increased with FAC concentration and decreased with PVA concentration. For acceptable mechanical stability and adsorption capacity, a FAC concentration of 12% and PVA concentration of 7.5% were suggested. The adsorption capacity of the granules prepared under suggested concentrations was 4.46 mg/g at an initial fluoride concentration of 19 mg/L and pH 6.5. Immobilization of the nano-adsorbent in porous polyvinyl alcohol granules is a promising granulation method for water treatment in packed beds.Nano-adsorbents of Fe–Al–Ce trimetal hydroxide were immobilized in porous polyvinyl alcohol via cross-linking with boric acid. The adsorbent particles were embedded in holes of about 10 μm in the PVA granules. Spherical composite granules of 3–5 mm in size were obtained, which is a promising adsorbent granules for water treatment in packed beds.Research highlights►Proposes a new adsorbent-substrate combination for nano-adsorbent granulation to be used for water treatment. Nano-adsorbents of Fe–Al–Ce trimetal hydroxide was granulated into spherical shapes of 3–5 mm in size by immobilizing it in a porous polyvinyl alcohol matrix via cross-linking with boric acid. ►Fe–Al–Ce trimetal hydroxide were embedded in a porous PVA matrix with holes of about 10 μm, while the surface pores of the granules were only on the nano-scale. This structure is promising for adsorption of fluoride ions. ►With spherical granules prepared in the research, satisfactory adsorption capacity and stability in water treatment were achieved.
Co-reporter:Lin Chen, Ting-Jie Wang, Hai-Xia Wu, Yong Jin, Yu Zhang, Xiao-Min Dou
Powder Technology 2011 Volume 206(Issue 3) pp:291-296
Publication Date(Web):30 January 2011
DOI:10.1016/j.powtec.2010.09.033
A coating granulation technology comprising the spraying of a Fe–Al–Ce nano-adsorbent suspension onto glass beads in a fluidized bed was developed. An acrylic-styrene copolymer latex was used as a binder. The granulated adsorbent was used in a packed bed for fluoride removal from drinking water. The effects of coating temperature, latex/Fe–Al–Ce ratio, and coating amount on granule compressive strength and adsorption capacity were investigated. With increased coating temperature, cross linking in the polymer in the coated layer increased, which resulted in increased granule strength but decreased adsorption capacity. With increased latex/Fe–Al–Ce ratio, more active sites were covered by the polymer, which also resulted in increased granule strength but decreased adsorption capacity. The optimal parameters for making high performance adsorbent granules were for the granules to be coated at 65 °C using a latex/Fe–Al–Ce ratio of 0.5:1 and a coating amount of 27.8%. These granules had a fluoride adsorption capacity of 2.77 mg/g (coated granules) for water with an initial fluoride concentration of 0.001 M that was treated at pH 7.The parameters for the granulation by spraying of a Fe–Al–Ce nano-adsorbent suspension onto glass beads in a fluidized bed were optimized. The granules having a suitable fluoride adsorption capacity and compressive strength were obtained, which can be used as a filter in a packed bed for fluoride removal from drinking water.
Co-reporter:Rui Lan, Yonghui Liu, Guanda Wang, Tingjie Wang, Chengyou Kan, Yong Jin
Particuology 2011 Volume 9(Issue 5) pp:510-516
Publication Date(Web):October 2011
DOI:10.1016/j.partic.2011.01.004
Spray coating of polymer latex onto fertilizer particles in a fluidized bed for producing controlled-release urea is an environment friendly technology as it does not need any toxic organic solvent. Since the spray coating process in a fluidized bed occurs in the presence of particle collisions, the coating of the particles is random, intermittent and multiple, thus making it difficult to investigate the film formation process. In this paper, an experimental model apparatus was designed and used to investigate the effects of the key factors in the spray coating process. This apparatus reasonably simplified the complex process to avoid particle collisions and randomness in the coating. The intermittent coating in the fluidized bed was modeled by periodic coating and dewatering in the experimental apparatus. A large area film was obtained, and the film permeability was measured. The effects of atomizing gas flow rate, spray rate of latex, solid content of latex and gas temperature on film structure and film permeability were investigated. It was found that water transfer played a dominant role in the spray coating process.An experimental model apparatus was designed and used to simulate random, intermittent, multiple coating-dewatering in fluidized bed for studying spray coating process in production of controlled-release urea. It was found that water transfer played a dominant role in the spray coating process.
Co-reporter:Ling Yang, Di An, Ting-Jie Wang, Chengyou Kan, Yong Jin
Particuology (February 2017) Volume 30() pp:73-82
Publication Date(Web):February 2017
DOI:10.1016/j.partic.2016.03.005
Co-reporter:Yingzhen Li, Chang Zhang, Yanping Jiang, Ting-Jie Wang, Haifeng Wang
Desalination (1 December 2016) Volume 399() pp:171-177
Publication Date(Web):1 December 2016
DOI:10.1016/j.desal.2016.09.011
•Electrosorption selectivity in a competitive multi-ionic solution was studied.•Monovalent ions with a low hydration ratio exhibit high selectivity.•Divalent ions demonstrate higher selectivity than monovalent ions.•The adsorbed ion is easily substituted by ions with lower hydration ratios.The electrosorption performances of different ions in a capacitive deionization process were studied. The hydration ratio, i.e., the ratio of hydrated radius to ion radius, significantly affects the electrosorption capacity and selectivity. In a mono-ionic solution, ions with low hydration ratios exhibit high electrosorption capacities. The electrosorption capacity demonstrates a negative linear relationship with the hydration ratio for both anions and cations. In a multi-ionic solution, the monovalent ions with low hydration ratios exhibited high electrosorption selectivity. Divalent ions adsorb more easily onto electrode surface than monovalent ions do, resulting in higher electrosorption selectivity. In the late period of the electrosorption, the adsorbed ions were partly substituted by ions with lower hydration ratios or a higher valence. The hydration ratio and valence affect the ions' electrostatic attraction to the electrodes, determining the electrosorption capacity and selectivity of ions in capacitive deionization.The hydration ratio, i.e., the ratio of hydrated radius to ion radius, significantly affects the electrosorption capacity and selectivity. Monovalent ions with a low hydration ratio exhibit high adsorption capacity and selectivity. The adsorbed ion is easily substituted by ions with lower hydration ratios or a higher valence.Download high-res image (228KB)Download full-size image
