Sevgi POLAT, Bahar DEMİRAY, Berfin TEKİN, Merve KARDAŞ

Kalsiyum Karbonatın Polimorfik Faz Dönüşümünün Prolin Varlığındaİncelenmesi

Bu çalışmada, kalsiyum karbonatın polimorfik faz dönüşümü katkı maddesi olarak kullanılan prolin varlığında incelenmiştir. Deneyler 1L kapasiteli çift ceketli kristalizörde, 30 C sıcaklık ve pH 8,5’da yürütülmüştür. 50 ve 100 ppm olmak üzere iki farklı katkı konsantrasyonunda deneyler gerçekleştirilmiştir. Reaktan olarak kalsiyum klorür dihidrat ve sodyum karbonat kullanılmıştır. Deney süresince belirli zaman aralıklarında numuneler alınarak, kristallerin yapısı, fonksiyonel grupları, morfolojisi, tane boyutları ve yüzey yüklerinin değişimi belirlenmiştir. XRD ve FTIR analiz sonuçları, kalsiyum karbonat kristallerinin prolin varlığında kalsit formundan vaterit formuna dönüştüğünü göstermiştir. SEM görüntüleri saf ortamda üretilen kalsit kristallerinin kübik formda olduğunu buna karşın prolin varlığında kristallerin yuvarlak görünümlü vaterit morfolojisine sahip kristallere dönüştüğünü göstermiştir. Ayrıca, prolinin kalsiyum karbonat kristallerinin yüzey alanına ve yüzey yüküne olan etkisi BET analizi ve zeta potansiyeli ölçümleri yapılarak belirlenmiştir. Saf ortamda üretilen kalsit kristallerinin BET yüzey alanı ve zeta potansiyeli değeri sırasıyla 0,7 m2/g ve –8,0 ± 2,1 mV olarak ölçülmüştür. Buna karşın, 100 ppm prolin varlığında kristallerin BET yüzey alanı 3.7 $m^2$/g’a yükselmiş ve prolinin kristallerin yüzeyine fiziksel olarak adsorplanmasından dolayı zeta potansiyel değerleri daha negatif (–24,0 ± 2,6 mV) hale gelmiştir. Sonuç olarak, katkı maddesi olarak kullanılan prolinin kalsiyum karbonatın hem fiziksel hem de morfolojik özelliklerini önemli ölçüde değiştirdiği gösterilmiş ve farklı formlarda kalsiyum karbonat kristallerinin üretilmesine imkân sağlayacağı tespit edilmiştir.

An Investigation of Polymorphism of Calcium Carbonate in the Presence of Proline

In this study, the polymorphic phase transformation of calcium carbonate was analyzed in the presenceof proline used as an additive. The experiments were carried out in a 1-litre double-jacketed crystallizer at 30 C and pH 8.5. The experiments were performed at two different concentrations of 50 and 100ppm. Calcium chloride dihydrate and sodium carbonate were used as the reactants. During thepolymorphic transformation process, the samples were withdrawn from the crystallizer at regular timeintervals and the structure, functional group, morphology, particle size and surface charges of thecalcium carbonate were determined as a function of the time. XRD and FTIR results showed that calciumcarbonate crystals transformed from calcite to vaterite structures in the presence of proline. SEMimages indicated that the calcium carbonate crystals prepared in pure media was cubic shaped crystals and the morphology transformed into spherical like vaterite crystals in the presence of proline. Moreover, the effects of proline on the surface area and surface charge of calcium carbonate were investigated by BET and zeta potential analysis. BET surface area and zeta potential for calcite crystalsprepared in pure media were 0.7 m2/ g and - 8.0 ± 2.1 mV, respectively. By the addition of proline tothe crystallization media, BET surface area increased to 3.7 $m^2$/g, and the surface became morenegative (- 24.0 ± 2.6 mV).

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Al Nasser, W.N. and Al Salhi, F.H., 2015. Kinetics determination of calcium carbonate precipitation behavior by inline techniques. Powder Technology, 270, 548-560.
Amer, L., Ouhenia, S., Belabbas, I. and Chateigner D., 2018. The effect of ergocalciferol on the precipitation of calcium carbonate. Journal of Crystal Growth, 501, 49-59.
Bastrzyk, A., Fiedot-Toboła, M., Polowczyk, I., Legawiec, K. and Płaza, G. 2019. Effect of a lipopeptide biosurfactant on the precipitation of calcium carbonate, Colloids and Surfaces B: Biointerfaces, 174, 145-152.
Choi, K.M. and Kuroda, K., 2012. Polymorph Control of Calcium Carbonate on the Surface of Mesoporous Silica. Crystal. Growth Design, 12, 887-893.
Dhami, N.K., Reddy, M.S. and Mukherjee, A., 2013. Biomineralization of Calcium Carbonates and Their Engineered Applications: A Rewiev. Frontiers in Microbiology, 4, 314.
El-Sheikh, S.M., El-Sherbiny, S., Barhoum, A. and Deng, Y., 2013. Effects of cationic surfactant during the precipitation of calcium carbonate nano-particles on their size, morphology, and other characteristics. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 422, 44-49.
Hu, Y.B., Wolthers, M., Wolf-Gladrow, D.A. and Nehrke, G. 2015. Effect of pH and Phosphate on Calcium Carbonate Polymorphs Precipitated at near-Freezing Temperature. Crystal Growth & Design, 15, 1596- 1601.
Kirboga, S., Oner, M. and Akyol, E., 2014. The effect of ultrasonication on calcium carbonate crystallization in the presence of biopolymer. Journal of Crystal Growth, 401, 266-270.
Konrad, F., Purgstaller, B., Gallien, F., Mavromatis, V., Gane, P. and Dietzel, M. 2018. Influence of aqueous Mg concentration on the transformation of amorphous calcium carbonate. Journal of Crystal Growth, 498, 381-390.
Lee, T.J., Hong, S.J., Park, J.Y. and Kim, H.J., 2015. Effects of Anionic Polyacrylamide on Carbonation for the Crystallization of Precipitated Calcium Carbonate. Crystal Growth & Design, 15, 1652-1657.
Liu, Y., Chen, Y., Huang, X. and Wu, G., 2017. Biomimetic synthesis of calcium carbonate with different morphologies and polymorphs in the presence of bovine serum albumin and soluble starch. Materials Science and Engineering C, 79, 457–464.
Mori, Y., Enomae, T. and Isogai, A., 2010. Application of Vaterite-Type Calcium Carbonate Prepared by Ultrasound for Ink Jet Paper. Journal of Imaging Science and Technology, 54, 020504-6.
Oral, C.M. and Ercan, B., 2018. Influence of pH on morphology, size and polymorph of room temperature synthesized calcium carbonate particles. Powder Technology, 339, 781-788.
Polat, S., 2019. Evaluation of the effects of sodium laurate on calcium carbonate precipitation: Characterization and optimization studies. Journal of Crystal Growth, 508, 8-18.
Popescu, M.A., Isopescu, R., Matei, C., Fagarasan, G. and Plescu, V., 2014. Thermal Decomposition of Calcium Carbonate Polymorphs Precipitated in the presence of Ammonia and Alkylamines. Advanced Powder Technology, 25, 500-507.
Price, G.J., Mahon, M.F., Shannon, J. and Cooper, C., 2011. Composition of Calcium Carbonate Polymorphs Precipitated Using Ultrasound. Crystal Growth & Design, 11, 39-44.
Stajner, L., Kontrec, J., Dzakula, B.N., Maltar-Strmecki, N., Plodinec, M., Lyons, D.M. and Kralj, D. 2018. The Effect of Different Amino Acids on Spontaneous Precipitation of Calcium Carbonate Polymorphs Journal of Crystal Growth, 486, 71-81.
Toraman, Ö.Y., 2015. Kalsiyum Karbonatın ($CaCO_3$) Mikron Altı/Nano Boyutta Yaş Öğütülmesi: Öğütme Parametreleri ve Pülp Stabilitesi Aşınma İndeksi Arasındaki İlişkilerin İncelenmesi. MT Bilimsel, 8, 15- 22.
Wada, N., Kanamura, K., Umegaki, T. 2001. Effects of Carboxylic Acids on the Crystallization of Calcium Carbonate. Journal of Colloid and Interface Science, 233, 65-72.