Directly Observe Sodium Chloride - Lab Report Example

OBSERVE SODIUM CHLORIDE, SODIUM CARBONATE, SODIUM SULPHATE AND SODIUM NITRATE AGGREGATES WALTZING THROUGH DILUTE SOLUTIONS Name: Course Professor’s name University name City, State 1.0 Abstract Generally, the crystallization process, defines both physical properties and chemical purity such as particle size and habit, polymorph (crystal structure) and the extent of crystal imperfection. During this process, particles dispersed within the dilute solutions coalesce thereby sticking to each other, and spontaneously creating irregular particles such i.e. aggregates, flocs etc. Generally, deposition and aggregation of tiny solid particles from a saturated liquid dispersion can be encountered in a number of situations within manufacturing and process technologies as well as in the natural environment. Deposition may occur in two ways. First, the aggregates may consolidate onto the surface dipped into the suspension; this involves the macroscopic dimensions as compared to the particle. Secondly, solids deposits may settle as a result of gravity leading to sedimentation along the bottom of the vessel containing the mixture. This experiment is aimed at studying the effect of impurities on crystal shapes and sizes in solution is meaningful to the industries to have expected products. If we can study the shapes and sizes of salt related to colour, we can help the industry (e.g. textile industry) reduce the rework hence saving time and money. Experiments have been conducted an experiments which involves the measuring the concentration of the sodium ions (Na+), within a concentrated solutions using an Inductively Coupled Plasma (ICP). In the experiment a membrane pore enlargement was observed nanofiltration membrane was as conductivity rose linearly at lower salt concentrations although this was not replicated at higher concentrations. Another crucial benefit of this research finding, is the ability to observe the direct growth and hence the formation of the salt aggregates. This makes it possible to understand the mechanism involved in the salting out through observing directly salt aggregates connecting to the macromolecules, protein crystallization; and hence the effective interaction of water with molecules from another substance by straight observation of the dynamic and structural properties The project involves the direct observe sodium chloride, sodium carbonate, sodium sulphate and sodium nitrate aggregates waltzing through dilute solutions. The report involves the study the effect of impurities on crystal shapes and sizes in solution are meaningful to the industries to have expected products. 2.0 Acknowledgement 3.0 4.0 Table of Contents 1.0 Abstract 2 2.0 Acknowledgement 4 4.0 Table of Contents 5 5.0 List of Figures 6 7.0 Introduction 7 8.0 Literature Review 8 a. Understanding Crystallization and the role of impurities 12 b. Application of study of crystallization 13 c. Particle Size Distribution 15 d. Conductivity 21 e. PH 22 9.0 Methodology 25 Materials and methods 25 Equipment 27 Experiment Procedure 27 10.0 References 29 5.0 List of Figures Figure 1: Solid Aggregate 10 Figure 2: Crystals observed was the watery ball 11 Figure 3: Solid crystal 11 Figure 4: Size distribution of 2M Sodium chloride solutions at room temperature 15 Figure 5: Relationship among PH of KN03, K2SO4, KCl, KCo3 salts solution and Deionised Water vs Concentration 21 Figure 6: Relationship of Conductivity of KCI solution and concentration. 21 Figure 7: Relationship among particle size of the salt solutions versus concentrations in comparison with the Deionised water 23 Figure 8: Relationship among particle size of the potassium salts solutions 24 6.0 7.0 Introduction Crystallization and particle Engineering Solution crystallization have been largely adopted as an industrial purification technique as well as a separation process in pharmaceuticals, textile and chemical industries. For instance over 90% of the pharmaceutical products contain some element of particulate drug substance, essentially in crystalline form (Sendhil, 2003). Nevertheless, conventionally, crystallization has been largely regarded as a ‘low tech’ area of chemical production. It is due to this, that industrial crystallization as a large scale unit is still largely adopted despite the many misunderstood concepts and aspects (Myerson , 2002). Generally, the crystallization process, defines both physical properties and chemical purity such as particle size and habit, polymorph (crystal structure) and the extent of crystal imperfection. Chemical purity is of greatest importance especially in the pharmaceutical industry due to their direct consequence on the therapeutic effects. On the other hand, still in the drugs sector, the operational characteristics during processing can be greatly affected by the solid state physical properties of the crystals. For instance, in product filtration, the process can be profoundly affected by the crystal particle size distribution and habit. Another crucial benefit of this research finding, is the ability to observe the direct growth and hence the formation of the salt aggregates. This makes it possible to understand the mechanism involved in the salting out through observing directly salt aggregates connecting to the macromolecules, protein crystallization; and hence the effective interaction of water with molecules from another substance by straight observation of the dynamic and structural properties Ideally the shape of a crystal as it develops from a pure solution is usually dictated by the relative rates of growth of its crystallographic surfaces, with the slow developing surfaces likely to determine the final behaviour. Nonetheless, the presence of impurities in trace quantities in crystallizing solutions can greatly modify the habits of crystal, subsequently leading to the inhibition of normal growth to the affected face (Myerson , 2002). 8.0 Literature Review Particle aggregation refers to the formation of clusters within a colloidal system. During this process, particles dispersed within the dilute solutions coalesce thereby sticking to each other, and spontaneously creating irregular particles such i.e. aggregates, flocs etc. this process is called flocculation or coagulation and can be boosted by adding salts or any other chemical (Levin, et al., 2004). During the coagulation process, the aggregates settle at the bottom of the container in what is referred to as sedimentation Hakkinen, et al., 1995). The impact of impurities on crystal growth is dependent on the solution super saturation and impurity concentration. Any impurity molecule found on the surface of a crystal leads to an effected known as “pinning”, thus hindering the growth of subsequent layers. This leads to creation of a “dead” zone of super saturation, a point at which there exists a retardation of further step advancement (Myerson , 2002). Ideally, particle aggregation is an irreversible process. Once formed, particle aggregates cannot be easily disrupted. The aggregates instead increases in size thus consolidate onto the surface dipped into the suspension; According to ( Elimelech, et al., 2012), deposition and aggregation of tiny solid particles from a saturated liquid dispersion can be encountered in a number of situations within manufacturing and process technologies as well as in the natural environment. Deposition may occur in two ways. First, the aggregates may consolidate onto the surface dipped into the suspension; this involves the macroscopic dimensions as compared to the particle. Secondly, solids deposits may settle as a result of gravity leading to sedimentation along the bottom of the vessel containing the mixture. ( Elimelech, et al., 2012), concludes that aggregation occurs when solid particles assembles on a surface or to one another as a result of collision, and contact to the surface forces. Basing of mechanistic view point, deposition onto a macroscopic surface can be assumed to be the limiting case of particle- particle aggregation under which a particle has indefinite dimension. The phenomena are of crucial industrial importance in biological, environmental, mineral and chemical sectors. For instance, depositions process has been for a long time applied in the preparation of magnetic tapes, water purification, and in selective capture of solids. The aggregation to create bigger assemblies of particles is an vital step in the gravitational settling to permit improved dewatering of solid suspensions, as well as indiscriminate flocculation processes (Myerson , 2002). To develop more understanding on crystallization, (Shu, et al., 2013), conducted an experiments which involves the measuring of the concentration of the sodium ions (Na+), within a concentrated solutions using an Inductively Coupled Plasma (ICP). In the experiment a membrane pore enlargement was observed nanofiltration membrane was as conductivity rose linearly at lower salt concentrations although this was not replicated at higher concentrations. (Shu, et al., 2013), also concludes that a number of methods have been adopted in the measuring of the sodium chloride crystals or aggregates. Some of these methods include Raman Scattering, UV- visible Spectrometer, Masteriser and Nanosizer. (Shu, et al., 2013), suggests that measuring the sodium ions concentration for solution with a concentration of over 500mg/L of sodium chloride using ICP, it is prudent to first dilute the sodium chloride solution. In some instances even after diluting, an acid needs to be added to the solution in order fot the sodium ions (Na+) to be dispersed (Shu, et al., 2013). Using a powerful microscope, (Shu, et al., 2013) observed the different types of crystals. The first type of crystal was a solid one as shown in figure 1, below; with the second type of crystals observed was the watery ball as shown in figure 2. The third type of solid crystal observed using the OLYMPUS, DP70 microscope was in form of a white cloud. Figure 1: Solid Aggregate Figure 2: Crystals observed was the watery ball Figure 3: Solid crystal The sizes of watery ball salt aggregates have been sampled were quite large with some cases being more than 100micrometers, in at least one dimensions, although in true dimensions, particle sizes are less that metres. The salt shaped salt aggregates were quite stable with their presence conspicuous in the following solutions; 5mol/L of solution that was 5 months old 1 mol/L of solution after filtration 0.001mol/ L of a week of salt solution The several rings within the ball were attributes to the difference in concentration. For instance in the watery ball show in figure 1 above, the centre the salt aggregates were , the adjacent layer was , the third layer is , and subsequently and so on. (Shu, et al., 2013), asserts that further research is necessary to explore further the said observation. The salt aggregates with the solution were noted to be quite changeable. For instance at the beginning, it was noted the presence one or two large aggregates as viewed under the microscope, although this depended on the salt concentration. Another one or two aggregates were observed after ten minutes. A circle of salt was conspicuous was detected when the after all the water dried up, thereby making the small salt aggregates to appear somehow interlinked to each other, with some of them appearing in formed lines. a. Understanding Crystallization and the role of impurities Crystallization is basically a super molecular process through which a randomly organized molecules i.e. solute within a solution coalesce to create an ordered 3- dimensional array of molecules (Sangwal, 1993). The effectiveness of crystallization lies on the understanding that the growth of crystals is far and large particular to the respective product molecules, with any undue impurities being readily ejected from the continuously developing crystal surface. (Sendhil, 2003), asserts that in such cases a comparatively high purity crystals are easily obtained from solutions of varying concentration levels and which may have a lot of impurities (Vasanth, 2010). Nevertheless, (Sendhil, 2003), also asserts that a number of contained impurities may influence with the normal process of crystal growth process, in what is popularly called ‘molecular trickery’ and thereby affect the key attributes of growth of crystals. Such impurities possess typically similar molecular structure to those exhibited by the primary solute, and can therefore react with the additives, reactants and by- products from the reactions. (Sendhil, 2003), therefore underscores the significance of studying and understanding the role played by impurities on crystal growth process, crucial for a robust process development. This has led to the development of considerable insights in the development of a notion of ‘tailor made’ additives. b. Application of study of crystallization In line with the observations, industrial establishment use industrial grade chemicals, ground water and tap water with minimal treatment in their processes. It is therefore vital to understand the effect of impurities on crystal sizes and shapes as they appear in solutions so as to achieve the desired products. For instance, although textile mills use standard materials and use standard process in drying the fabrics, very often they end up with different products from the desired runs and therefore ends up re- dyeing the fabric. (Shu, et al., 2013), asserts if proper design is carried out to study the sizes and shapes concerning colour, the industry can effectively minimize significantly the current rework procedures, thereby saving on energy and time, hence boosting profitability. The dynamic nature of the aggregates creates a challenge to the technical researchers. Conversely, this offers an opportunity to research novel ideas. For instance, (Shu, et al., 2013), revealed that the PH of sodium chloride solution was not neutral. After working on the corrosive properties exhibited by the Sodium chloride salt it was evident that the salt is exclusive. Another crucial benefit of this research finding, is the ability to observe the direct growth and hence the formation of the salt aggregates. This makes it possible to understand the mechanism involved in the salting out through observing directly salt aggregates connecting to the macromolecules, protein crystallization; and hence the effective interaction of water with molecules from another substance by straight observation of the dynamic and structural properties (Abraham, 1974). Through the same principle, it may be possible to understand how salt aggregates attached to the cell membrane of a bacteria, and thus understanding and appreciating the food preservation principle. Also, it is possible to understand the insight into the reasons why conductivity and PH values are not equal in the middle of the solution to those near the beaker wall or at the bottom of the beaker. Another interesting field worth researching is the dissolution test. This can give the researcher an unprecedented view of salt dynamic and dissolution as well as aggregate formation. c. Particle Size Distribution From the experiments conducted by (Shu, et al., 2013), it became apparent that at certain temperatures, salt aggregates exhibited different sizes. For instance in one the tests (using a nanosizer to measure sodium chloride solutions from 0.00001 to 7M), out of the one hundred salt aggregate measurements conducted, only two sets were valid as per the nanosizer used. Majority of the particles ranged from 100 to 1000 micrometres, at room temperatures. There were still some salt aggregates which recorded more than 1000nm. According to (Xi, 2014), particle aggregate size is used in defining crystal materials properties by their diameter. Figure 4: Size distribution of 2M Sodium chloride solutions at room temperature According to (Hakkinen, et al., 1995), solutions with particles ranging from 2 to 1000nm are termed as colloidal. Ideally the sizes of particles present in unsaturated sodium chloride solutions spot similar particle sizes as colloidal. However, such particles can penetrate through pass filters of 200 Dalton ( this refers to such filters that can permit molecules with molecular weight lower than 200 g/mol to go through) (Hakkinen, et al., 1995) (Shu, et al., 2013), approximates that it requires about 22.5million NaCl molecules to create an aggregate of cubic shape with 100nm sides, and weighing 2.168x1015 grams. It was also noted that although the nanosizer used could measure a particle down to 0.6nm, it did not detect particles of sizes less than 2nm. This was attributed to the understanding that there could be a possibility that dissolution of NaCl to the constituent ions of Na+ and Cl- occurring on the salt aggregate surface. In a larger salt aggregate, the bigger proportion of the salts is not found on the salt aggregate but rather buried with the aggregate itself. (Coulson , et al., 1997), noted that the surface area to volume ratio of a particle tends to decrease 4 folds of magnitude when its size increases from 1nm to 10nm. This may lead to diverse outcomes when modelling charge energy and charge within a system. (Shu, et al., 2013), cites that this could be the reason why conductivity fails to rise lineally as concentration increases. In a nutshell, this means that less efficiency of current conduction is achieved when salt is “buried” within the salt aggregate. (Shu, et al., 2013), suggests that this is a qualitative conclusion, requiring the generation of quantifiable data obtained from further tests and studies. Ideally in formation of crystal aggregates, the physical process involved in the crystal growth and nucleation are inherent to the biological process of mineralization. One of the key challenges present is the need to understand how the bio minerals are formed, thus being in apposition ton decipher the control mechanisms. ( De Yoreo & Vekilov , 2010), concludes that the concept of energy landscape, although not fully attached, offers a framework for showing the existing interfaces between the controlling crystallizing agents and the physical changes in the crystals shape, phase and structure. The key point to note is the fact that crystallization is the impact of the relationship between critical size and external control parameter (Kahlweit M , 1969)r. More vitally, the extent of the interfacial energy is based on the atomic- scale at the interface and as such, surfaces can be transformed by organisms to determine both the orientation and location of the formed crystal aggregates ( De Yoreo & Vekilov , 2010), Unfortunately, although these concepts are founded on a solid physical foundation, more precise and connections to the real systems needs to be established. Among the critical concepts that occur during the phase of crystal growth include the free energy barriers and critical growth, however the potential mechanisms used for controlling the process seems to greater in magnitude and diversity. This critical factors continue to include free energy and super saturation, however, the free energy boundary is superseded by that of the step ( De Yoreo & Vekilov , 2010). Additionally, the attachment and detachment kinematics are of equal importance in shaping the crystals shapes and rates of growth. These processes are generally quantified by one unique parameter, the coefficient of kinetics, which unfortunately conceals the physics behind crystal formation. Amazingly, although many processes such as absorption, chemical reaction dissolution, surface diffusion, in principle, all impact on the kinetics coefficient although this depends on the fine details of the system chemistry (Abraham, 1974). (Shu, et al., 2013), concluded from his observations of particle size distribution that sodium chloride does not completely dissolve in water. It creates salt aggregates. This means that sodium chloride solutions are not true solutions as low as 0.00001M (molar) concentrations. If highly soluble sodium chloride salts can create salt aggregates at such dilute solutions; it because logical and thus rather obvious to conclude that other types of salts as well other substances with similar of lower solubility should also form aggregates in their dilute solutions. This assertion forms the basis of this research. This research seeks to determine (Shu, et al., 2013) inference that aggregation is a wide spread phenomenon. According to (Shu, et al., 2013), the quantity of salt aggregates in a litre of solution at difference concentrations is shown in table 1 below. This gives the quantity of aggregates at 10-13M of sodium chloride solutions. Table 1: Numbers of aggregates at different mean particle sizes By discovering the present sodium salt aggregates within the dilute solutions, (Shu, et al., 2013), suggests that the properties of salt solutions could be quantified, such as crystallization, aggregation, transportation, depositions which were encountered in biological, mineral, chemical and environmental sectors. The advantage of conducting the experiment is the ability to measure the physical properties of the salt aggregate such as size of particle, their distribution, and other surface properties in the solutions due to the fact that salt has surface and size. (Xi, 2014) (Xi, 2014), conducted an experiment to measure and analysis dynamics of multi aspect of potassium salts by increasing the solution concentration. In the experiment, the selected solutions were of different concentrations ranging from 0.0001M/L from 6M/L by using four potassium based salts such as potassium carbonate (K2Co3), Potassium sulphate, potassium chloride and potassium nitrate. In the experiment, the carried out analysis of the main properties such as conductivity, PH and particle size with respect to concentration (Xi, 2014). According to (Xi, 2014), there is a relationship of PH among the considered potassium salts versus concentration. The study concluded that PH of deionised water was at about 5.6 and it was near the figure recorded to KNO3. Since potassium carbonate was alkaline, its PH level was considerably higher that, with a larger gradient with rise in concentration as shown in figure 5. Below. Figure 5: Relationship among PH of KN03, K2SO4, KCl, KCo3 salts solution and Deionised Water vs Concentration From figure 5 above, it was evident that a higher saturation was recorded in K2Co3, as well as a greater gradient with the increase in concentration. The PH for all salts was slightly similar; however the PH of K2so4 was also stagnating when it reached saturation. d. Conductivity Electrical conductivity refers to the amount of a substance that can be converted into electrical current. The units of electrical conductivity are µm/cm, and are influence by temperature, presence of solid conductor and concentration levels. During an experiment conducted explained by (Xi, 2014), conductivity results varied depending on the levels of concentration, as shown in figure 6 below. Figure 6: Relationship of Conductivity of KCI solution and concentration. Figure 6 provides the relationship between the concentration KCI salt solution and concentration. It was apparent that conductivity of solution increased with the increase of concentration; however the relationship is not linear as concentration increased. e. PH Potential Hydrogen (PH) refers to the ratio of hydrogen ion concentration in a solution to the total volume of solution. PH of solution influences a number of physical parameters exhibited by salts. Some of these parameters include, suspension, carbon dioxide concentration, dusts etc. Ideally, PH serves as a parameter for determining the acidic and alkalinity of a salt solution. The percentage of particle intensity, molecules contained can be obtained from the particle size analysis. From this one can visibly see the particle size of the object. The particle aggregate size just like other tiny objects can be determined through measuring of the diameter. The size distribution of the object may be determined thereby providing the intensity and quantity of the particle aggregation. Particle size is vital in determining their material properties by their diameter. In the experiment (Xi, 2014), used a Nanosizer machine to measure the particle size distribution in shape to define the size of salt aggregates within a dilute salt solution, as shown in figure 8 below. Figure 7: Relationship among particle size of the salt solutions versus concentrations in comparison with the Deionised water From the figure 7 above it is evident that the mean particle diameter sizes of the measure potassium salts was ranging between 200 and 1200µm, with the diameters of the deionised water ranging from between 150 to 200µm. (Xi, 2014), concluded that there was no conspicuous interaction between particle diameter sizes measured and concentration. There was however an exception, in KCl solution, where the diameter of the measured particles increased as concentration increased. Another notable difference was the decrease in K2CO3 particle sizes with the decreased in concentration from 0.0001M/l to 1M/L. the graph produced by K2SO4 salt solution was very stable, since it failed to show an understandable trend with the change in concentration. Figure 8, below gives an outline of the particle size distribution with respect to the molecule intensity of the potassium salts solution ranging from 0.0001M/L. Figure 8: Relationship among particle size of the potassium salts solutions From the information in figure 8 above, it shows that from large to smallest size of particle diameter, was as in the following sequence KCL, KNO3, K2SO4, K2CO4, and followed by deionised water. It was also shown that the size distribution of each salt solution, Potassium chloride aggregated at between 500nm to 1100nm, potassium nitrate aggregated at a range of between 400 to 1000nm, potassium sulphate at between 250nm and 950nm, and lastly deionised water aggregated at around 90nm and 200nm. The potassium salts also exhibited a different intensity of size distribution with K2SO4 solution depicting more concentrations, and potassium carbonate showing a higher geographical dispersion in distribution. (Xi, 2014), concludes with the relationship of PH value for the four different potassium salts at different dilute concentrations from the observations carried out. 9.0 Methodology The proposed project involves the direct observe sodium chloride, sodium carbonate, sodium sulphate and sodium nitrate aggregates waltzing through dilute solutions. The report involves the study the effect of impurities on crystal shapes and sizes in solution are meaningful to the industries to have expected products. It can be understood that the study the shapes and sizes of salt related to colour, can be useful to the industry (e.g. textile industry) reduce the rework hence saving time and money. In this study, two main experiments will be carried out. These are: direct observation of salt aggregates measurements of aggregate sizes Materials and methods Nacl, Na2CO3, Na2SO4, NaNO3 solutions are made with Milli Q water of concentration at from 0.0001 mol/L-5 mol/L. The solution sample is poured into three bottles. Bottle 1 for measuring pH and conductivity Bottle 2 for observing particles Bottle 3 for measuring size and size distribution using a Nanosizer The project seeks to determine the particle size, PH Conductivity data of potassium salts of diverse concentration of solutions, ranging from 0.0001M/L to 6M/L. for sodium chloride, sodium carbonate, sodium sulphate and sodium nitrate aggregates. The relative atomic mass of the four salts NaCl 28 Na2SO4 70 Na2CO3 52 NaNO3 41 The aim of this experiment is to study the conductivity, PH levels and particle aggregate sizes on different sodium salts concentrations. To produce a 100ml by volume= To produce the test specimen, three samples will be produced for the concentration of each salt solution. K2CO3, NaCO3, NaSO4, and NaCl solutions of different concentrations will be prepared at room temperature by mixing separately with 100ml of Deionised water. Quantifying portions will be used carefully to give the precise concentration of salts solution. From each sample 20ml will be put in glass container with the top cover for more analysis. An electronic scale will be used to weigh the salts. To scoop the salts, a clean plastic spoon and salver will be used. Small salt concentrations of 0.001M/L and 0.001M?L solution will be prepared by scale using a pipette through diluting 1M/L. Higher concentrations such as 4M/L and 6M/L will be stored in volumetric flask for later use with a seal. Equipment In this project the equipment to be used includes: Beaker. Beakers of varying sizes and volumes will be used to take samples as well as testing Volumetric flask: this will be used for mixing the salts and deionised water to get the solution of different concentration Pipette and bulb: they will be used for double checking the small quantities of sample dilute at lower concentrations Electronic Scale: the scale will be used for measuring the dry salts prior to mixing with the deionised water PH meter: the meter will be used for measuring the PH value as well as temperature of the salts solutions at different concentrations. Conductivity meter: the meter will be used for measuring temperature and conductivity of the salt solutions Nanosizer machine: the machine will be used for the salts crystal aggregate size and distribution Experiment Procedure a. Procedure for determine the salts PH and Conductivity In this experiment the PH and conductivity meters will be put on and then placed into a technical buffer to ensure the meters are fully set up. An electronic meter was used to measure the desired weight of salt granules The salt was mixed with 100ml of deionised water in a volumetric flask When the solution fully dissolves, it will be poured into a mixing beaker and the meters put in. Meter readings will be read and data recorded High concentrations of the sample solutions may take more than 24hours to saturate or fully dissolve especially at room temperature. In that case, the measurement will start after the solution stabilizes. b. Particle Size Sodium Salts particle sizes and distribution will be measured by Nanosizer which uses the cuboids plastic cell (DT0012) to contain samples. Samples will be taken from the 20ml glass container and saturated solutions from sealed volumetric flask. An Eppendorf tube will be used to take 1000µl solutions from the saturation solutions and later put into the plastic cell i.e.DTS0012. Samples will be carefully checked to ensure that there is no presence of any dust and air bubbles within the cell Nanosizer machine will be connected to a PC computer, and the DTS (nano) software used to analyse as well as resize data on the particle size. NOTE: the purpose of the above will be to discover the potential changes on particle size distribution on diverse concentration of sodium salts, and the potential relationship with PH, conductivity and solution saturation. 10.0 References De Yoreo , J. & Vekilov , G. P., 2010. Principles of Crystal Nucleation and Growth. Journal of Chemistry and Materials Science Directorate Lawrence Livermore National Laboratory . Elimelech, M., Xiadong , J., Gregory, J. & Richard , W., 2012. Particle Deposition & Aggregation: Measurement, Modelling and Simulation. London: Butterworth-Heinemann. Abraham, F. F., 1974. Homogeneous Nucleation Theory.. New York: Academic Press. Coulson , R., Backhurst, J. R. & Harker, J. H., 1997. Chemical Engineering, particle technology and seperation processes. Oxford: Heinemann. Hakkinen, M., Barnett, R. & Landman, U., 1995. Energetics, structure and excess electrons in small- chloride custers. Chemical Physical let. Kahlweit M , M., 1969. Nucleation in Liquid solutions. In: Physical Chemistry,. New York: Academic Press,. Kern , R., 1969. Crystal growth and adsorption. In: Growth of Crystals. Sheftal’ NN (ed). New York: Consultants Bureau. Levin, I., Topacik, D. & Weisner, M. R., 2004. Factors influencing flux decline during nanofiltration of solutions containing salts dyes. Journal of Water Resources. Myerson , A. S., 2002. Handbook of Industrial Crystallization. Woburn: Butterworth-Heinemann. Sangwal, K., 1993. Effect of Impurities on the crystal growth process. Journal of Crystallisation Growth. Sendhil, K. P., 2003. Effects of Impurities on Crystals growth. Department of Chemical and biomelecular engineering; University of Singapore. Shu, L., Shuang, W. & Jegatheesan, V., 2013. Directly observe sodium chloride aggregates waltzing through dilute solutions. Slutions to environmental challenges through information in research. Vasanth, K. K., 2010. Transfer of impurities into crystals in industrial processes: Mechanism and Kinetics. Journal of University of Porto. Xi, L., 2014. Changes of PH, conductivity and Particle sizes of potassium salts at room temperature. Read More

Nonetheless, the presence of impurities in trace quantities in crystallizing solutions can greatly modify the habits of crystal, subsequently leading to the inhibition of normal growth to the affected face (Myerson , 2002). 8.0 Literature Review Particle aggregation refers to the formation of clusters within a colloidal system. During this process, particles dispersed within the dilute solutions coalesce thereby sticking to each other, and spontaneously creating irregular particles such i.e. aggregates, flocs etc.

this process is called flocculation or coagulation and can be boosted by adding salts or any other chemical (Levin, et al., 2004). During the coagulation process, the aggregates settle at the bottom of the container in what is referred to as sedimentation Hakkinen, et al., 1995). The impact of impurities on crystal growth is dependent on the solution super saturation and impurity concentration. Any impurity molecule found on the surface of a crystal leads to an effected known as “pinning”, thus hindering the growth of subsequent layers.

This leads to creation of a “dead” zone of super saturation, a point at which there exists a retardation of further step advancement (Myerson , 2002). Ideally, particle aggregation is an irreversible process. Once formed, particle aggregates cannot be easily disrupted. The aggregates instead increases in size thus consolidate onto the surface dipped into the suspension; According to ( Elimelech, et al., 2012), deposition and aggregation of tiny solid particles from a saturated liquid dispersion can be encountered in a number of situations within manufacturing and process technologies as well as in the natural environment.

Deposition may occur in two ways. First, the aggregates may consolidate onto the surface dipped into the suspension; this involves the macroscopic dimensions as compared to the particle. Secondly, solids deposits may settle as a result of gravity leading to sedimentation along the bottom of the vessel containing the mixture. ( Elimelech, et al., 2012), concludes that aggregation occurs when solid particles assembles on a surface or to one another as a result of collision, and contact to the surface forces.

Basing of mechanistic view point, deposition onto a macroscopic surface can be assumed to be the limiting case of particle- particle aggregation under which a particle has indefinite dimension. The phenomena are of crucial industrial importance in biological, environmental, mineral and chemical sectors. For instance, depositions process has been for a long time applied in the preparation of magnetic tapes, water purification, and in selective capture of solids. The aggregation to create bigger assemblies of particles is an vital step in the gravitational settling to permit improved dewatering of solid suspensions, as well as indiscriminate flocculation processes (Myerson , 2002).

To develop more understanding on crystallization, (Shu, et al., 2013), conducted an experiments which involves the measuring of the concentration of the sodium ions (Na+), within a concentrated solutions using an Inductively Coupled Plasma (ICP). In the experiment a membrane pore enlargement was observed nanofiltration membrane was as conductivity rose linearly at lower salt concentrations although this was not replicated at higher concentrations. (Shu, et al., 2013), also concludes that a number of methods have been adopted in the measuring of the sodium chloride crystals or aggregates.

Some of these methods include Raman Scattering, UV- visible Spectrometer, Masteriser and Nanosizer. (Shu, et al., 2013), suggests that measuring the sodium ions concentration for solution with a concentration of over 500mg/L of sodium chloride using ICP, it is prudent to first dilute the sodium chloride solution. In some instances even after diluting, an acid needs to be added to the solution in order fot the sodium ions (Na+) to be dispersed (Shu, et al., 2013). Using a powerful microscope, (Shu, et al.

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