Determination of the dependence of the structure of Zn-Al layered double hydroxides, as a matrix for functional anions intercalation, on synthesis conditions

Self Cite

Pigments are the main components of cosmetics, which determine both toxicity and consumer color characteristics. Zn-Al layered double hydroxides intercalated with anionic food dyes are promising pigments. The best sources of dyes for intercalation are natural ones. The most promising are spices. Natural dyes from spices are often biologically active substances. The parameters of samples of Zn-Al (Zn:Al=3:1) hydroxides intercalated with natural food dyes, synthesized in the medium of aqueous tinctures of saffron and safflower, were studied. The crystal structure of the samples was studied by X-ray phase analysis; color characteristics were studied by spectroscopy and calculation of parameters in the CIE L*a*b system. The possibility of synthesizing Zn-Al colored layered double hydroxides intercalated with natural dyes in the medium of saffron and safflower tinctures was shown. X-ray phase analysis showed that both pigment samples were layered double hydroxides with the α-Zn(OH)2 structure. For the pigment intercalated with saffron dye, the phenomenon of partial decomposition of Zn-Al LDH to ZnO during synthesis was revealed. The color characteristics of the samples were studied. Zn-Al LDH pigment synthesized in a saffron tincture had a bright yellow color determined by intercalated saffron carotenoids (crocin and crocetin). It was suggested that safflower dye flavonoids were partially hydrolyzed (red ones - cartamine and cartamidine, and yellow - Safflor Yellow A), which led to the formation of a dark orange-brown color of the sample. The prospects of using Zn-Al LDH intercalated with saffron food dyes as a cosmetic pigment were shown

Section: Discussion Of the Results Of Investigating The Characteristi...mentioning

confidence: 99%

Section: Methods For Obtaining Samples Of Ldh Pigmentsmentioning

confidence: 99%

Investigation of the characteristics of Zn-Al layered double hydroxides, intercalated with natural dyes from spices, as a cosmetic pigments

Кovalenko

Kotok

Borysenko³

et al. 2022

Self Cite

“…Aluminum atom has strength to poisoning active metal in a metal complex [46]. The balance ratio of zinc with aluminum in a Zn-Al anion intercalation matrix for double layer hydroxide increases surface adsorption capability [47]. The high concentration of alumina in the catalyst alters the magnetic properties of the pottery catalyst.…”

Section: Discussion Of Experimental Resultsmentioning

confidence: 99%

The analysis of Si/Al ratio on CGA decomposition in Indonesian traditional Kreweng pottery coffee roaster to maximize coffee acidity

Qiram

Hamidi

Yuliati

et al. 2022

The use of pottery pans lowers the roasting temperature and gives the product a more favorable taste. This study uncovers the role of pottery particle on chlorogenic acid (CGA) decomposition during roasting process. This study aims to design pottery pans and the roasting process that optimize the CGA content and quality of the coffee using Indonesian traditional ceramics from Banyuwangi, East java named Kreweng. The pottery was ground to between 74–1000 µm before activation. The elemental, phase, and morphology characterization performs on the coffee bean. The morphology characteristic of the pottery observed further using digital imaging technique to unravel the pores and boundaries. The impact of the pottery usage for coffee roasting also tested through coffee product pH measurement. The pottery morphology determines coffee product acidity. The smaller the pottery catalyst particle size results in more acid coffee. The pore and grain boundary concentration increases as the particle size decreases. At the same time, the Si/Al ratio was higher at the smaller catalyst particle size with higher porosity, grain boundaries, and absorption. The porosity and defects reveal the negatively charged faces of the pottery crystal edges. The charged faces revealed due to the pottery crystal vibration in response to heat during roasting process. The effectiveness of surface contact is greater due to the distribution of negative charges around the pores that attract OH- side of CGA. This interaction traps hydrogen proton on catalyst conductive surface. As a result, the CGA decomposes into several groups of atoms and molecules including H2 and CO2. The interaction with the catalyst transforms the macronutrient into aliphatic acid. Therefore, roasting media with a higher Si/Al ratio at smaller particle sizes with high micropores will increase the rate of decomposition and the acidity of coffee products.

“…It should be noted that the characteristics of LDH intercalated with functional anions are determined by the parameters of the matrix -LDH intercalated with anions of precursor salts. The structural characteristics of Zn-Al-NO 3 LDH obtained by different methods were studied in [59]. At the same time, the technological parameters of the matrix (LDH intercalated with precursor salt anions) are practically not studied, which makes it difficult to develop a technology for the production of LDH-based functional materials.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Determination of technological parameters of Zn-Al layered double hydroxides, as a matrix for functional anions intercalation, under different synthesis conditions

Кovalenko

Borysenko

Kotok

et al. 2022

Layered double hydroxides, especially Zn-Al, are valuable bases for intercalating various functional anions: dyes, drugs, food additives, etc. For purposeful development and optimization of the synthesis technology of functional materials based on Zn-Al layered double hydroxides, the technological parameters of Zn-Al nitrate layered double hydroxide samples (Zn:Al=4:1) synthesized at solution flow rates of 0.8 and 1.6 l/h, pH=7, 8, 9, 10 and t=10, 20, 30, 40, 50 and 60 °C were determined. The yield values of the samples were determined by the gravimetric method. The sedimentation rate was studied by measuring the normalized thickness of the precipitate layer (relative to the initial layer thickness) during 30 minutes of settling. It was found that with an increase in the synthesis pH, the yield increased from 74.68 % to 83.54 %. Increasing the flow rate of the solutions led to a decrease in yield. On the yield-synthesis temperature dependence, two sections of 10–20 °C and 30–60 °C were identified, within which an increase in temperature led to a decrease in yield. It is shown that with increasing synthesis pH, as well as the solution flow rate, the sedimentation rate increased significantly. At pH=10, almost complete sedimentation of the sample occurred within the first 5 minutes. The obtained data indicate that the pH of the zero charges of the Zn-Al-NO3 layered double hydroxide particles was close to 10. It was found that increasing the temperature reduced the sedimentation rate. An abnormally low sedimentation rate at a synthesis temperature of 30 °C and an abnormally high sedimentation rate at 50 °C were detected. The obtained data confirm the previously stated hypothesis regarding the change of the mechanism or kinetics of the formation of layered double hydroxides at temperatures of 30 °C and 50 °C