The effect of crystal surface roughness on impurity adsorption

Ferreira, António; Faria, Nuno; Rocha, Fernando

doi:10.1002/crat.200800412

Cited by 9 publications

(9 citation statements)

References 25 publications

(33 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The impurity concentration obtained in the crystals, at the end of the experiments, was 3.63 and 4.36 mg CaCl 2 /100 g crystals at 25 and 50 °C, respectively, for the impurity concentration in solution of 3 g/100 g H 2 O, and 5.79 and 6.94 mg CaCl 2 /100 g crystals at 25 and 50 °C, respectively, for the impurity concentration in solution of 10 g/100 g H 2 O. The adsorption results indicate that the impurity adsorption increases with temperature and impurity concentration, a phenomenon predicted by Ferreira et al…”

Section: Resultsmentioning

confidence: 75%

“…The impurity adsorption into the crystals at different temperatures was also studied. For that, potentiometric titration and high-performance liquid chromatography (HPLC) were used in order to quantify CaCl 2 and d -fructose and d -glucose, respectively. For the HPLC analysis, the column LiChospher 100 NH 2 , 5 μm, and the detector ELSD-Sedex Model 55-SEDERE (Alfortville, France) were used.…”

Section: Resultsmentioning

confidence: 99%

“…This effect increases with impurity concentration. The impurity influence on growth rate seems to be related to the integration process, as the impurity, according to dissolutions results (presented in Ferreira et al 33 ), slightly increases the diffusion coefficient of sucrose in solution. The impurity concentration obtained in the crystals, at the end of the experiments, was 3.63 and 4.36 mg CaCl 2 /100 g crystals at 25 and 50°C, respectively, for the impurity concentration in solution of 3 g/100 g H 2 O, and 5.79 and 6.94 mg CaCl 2 /100 g crystals at 25 and 50°C, respectively, for the impurity concentration in solution of 10 g/100 g H 2 O.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 89%

See 2 more Smart Citations

Using an Online Image Analysis Technique to Characterize Sucrose Crystal Morphology during a Crystallization Run

Ferreira

Faria²,

Rocha

et al. 2011

Ind. Eng. Chem. Res.

Self Cite

View full text Add to dashboard Cite

The morphological forms and habits of crystals and agglomeration are important properties on crystallization processes. Online techniques for realtime measurement of these properties are mandatory for a better comprehension of crystal growth phenomenon. The present paper presents and describes a new online method to determine the complexity level of a crystal or a population of crystals during a crystallization process. An image analysis technique is combined with discriminant factorial analysis leading to results that allow the computation of the complexity of crystals through the parameter agglomeration degree of crystals. With this methodology, it has been possible to distinguish online and automatically among three different classes of crystals according to their complexity. It further describes the application of such methodology on the study of CaCl 2 , D-fructose, and D-glucose influence on the crystallization of sucrose, namely, on crystal size, morphology, and complexity. The effect of supersaturation, growth rate, and impurity concentration on the type, amount, and complexity level of the agglomerates was determined at different temperatures. The combination of image analysis and kinetic results allowed to understand better the crystallization phenomena in the presence and absence of impurities. The image analysis results suggest the possible application of this tool for process control, optimizing, by this way, laboratory and industrial crystallizers. ' INTRODUCTIONThe impurities effect on crystal growth has been investigated over the years. A great deal of interest in this field is well attested in Sangwal's work. 1 Originating from raw materials and sometimes from production processes, the impurities affect not only the manufacturing process but also the crystallization kinetics. Some impurities act on the properties of the solutions while others act on the crystals surface, changing their morphology or habit. This morphology change is an important property that affects not only the downstream processing and handling but also the end-use functional properties. Crystal habit is closely associated with filterability, flowability, and compaction behavior among other properties. A sudden change in crystal habit may suggest the appearance of a new polymorph or the presence of trace impurities. Agglomeration may lead to profound changes in final product quality, as well as entrapment of unacceptable levels of occluded solvent, causing difficulties in washing and drying. 2 On the other hand, the impurity affinity for a specific crystal surface can be useful for crystal morphology changes. The tailormade additives have obtained great importance on crystal growth. They interact in specific ways with selected faces of crystalline materials, thereby inhibiting the growth of preselected faces, and not changing or changing slightly the growth of the other faces. Consequently, a specific crystal morphology is obtained. The additive molecules can lower the growth rate either by physically blocking the layers or by ...

show abstract

Section: Resultsmentioning

confidence: 75%

Section: Resultsmentioning

confidence: 99%

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 89%

See 1 more Smart Citation

Using an Online Image Analysis Technique to Characterize Sucrose Crystal Morphology during a Crystallization Run

Ferreira

Faria²,

Rocha

et al. 2011

Ind. Eng. Chem. Res.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The impurity adsorption is growth dependent and is strongly influenced by the crystal surface properties. Crystal with high surface roughness has lower impurity adsorption [27]. We conclude that the title crystal may have a nominal impurity adsorption.…”

Section: Afm Studiesmentioning

confidence: 85%

Study of growth condition and characterization of bisthiourea–zinc acetate (BTZA) crystal grown in silica gel

Sivanandan

Kalainathan

2015

Optical Materials

View full text Add to dashboard Cite

“…However, various product and process parameters, such as crystal growth rate, nature and concentration of the impurities, are possibly affecting the final product quality (Ferreira, Faria, & Rocha, 2009;Godshall, Vercelotti, & Triche, 2002;Lionnet, 1998aLionnet, , 1998bMantovani, Vaccari, Sgualdino, Aquilano, & Rubbo, 1986a, 1986bRein, 2007;Van der Poel, 2000). Much work concerning the processes of impurity inclusions has been reported.…”

mentioning

confidence: 99%

The influence of the linear growth velocity on the properties of sucrose crystals produced from mixed syrups

Schlumbach

Schwenkler

Flöter

2018

J Food Process Engineering

View full text Add to dashboard Cite

The systematic study presented addresses the need to understand the co‐crystallization of beet and cane material better. This is important because of the sugar market liberalization in 2017. Here the effect of crystal growth velocity on final sugar quality is investigated. Comparing three different thermal setups, studying different cane and beet mixtures color inclusion into sucrose crystals was analyzed. Within one thermal setup supersaturation was practically constant. Almost exclusively the time necessary to complete the crystallization at 50% solids level changed. Particle size and distribution remained unchanged. Hence, only the growth velocity varied. Growth rate appears to influence color inclusion less than mixing of beet and cane syrups. In cane syrups the relative color inclusion is the highest and most sensitive to growth velocities. Admixing only 33% of beet syrup, already changes this pattern dramatically and the color transfer factor is more than halved. This effect of beet material is most prominent for the mechanism liquid inclusion but also significant for co‐crystallization of colorants. This observation is possibly due to the different nature of the colorants originating from beet and cane. The findings provide a framework to optimize the space‐time yield under consideration of highest sugar quality to manufacturers. Practical applications Co‐production of beet and cane is a promising opportunity to increase competitiveness by increasing utilization of equipment in the seasonal sugar industry. To do so reliably, quality parameters have to be met. The main problem to be solved is the control of white sugar color. Since cane and sugar beet deliver different coloring minor components, their interaction and respective inclusion mechanisms need to be understood. The work presented is part of a comprehensive study to elucidate this area of sugar processing that has not been studied yet. Next to the findings on inclusion characteristic and relative contribution of different mechanisms, the conclusions can directly be transferred into practice. The data gathered give a clear guidance to producers that higher inclusion levels of “colored” material, than current conservative practice dictates, can be tolerated due to the mutual suppression mechanism found.

show abstract

The effect of crystal surface roughness on impurity adsorption

Cited by 9 publications

References 25 publications

Using an Online Image Analysis Technique to Characterize Sucrose Crystal Morphology during a Crystallization Run

Using an Online Image Analysis Technique to Characterize Sucrose Crystal Morphology during a Crystallization Run

Study of growth condition and characterization of bisthiourea–zinc acetate (BTZA) crystal grown in silica gel

The influence of the linear growth velocity on the properties of sucrose crystals produced from mixed syrups

Contact Info

Product

Resources

About