Joaldo S. Lopes , Marcelo L. Morais , Alan I.S. Morais , Roosevelt D.S. Bezerra , Josy A.O. Furtini , Edson C. Silva Filho
{"title":"A new method for reducing impurities in clay minerals","authors":"Joaldo S. Lopes , Marcelo L. Morais , Alan I.S. Morais , Roosevelt D.S. Bezerra , Josy A.O. Furtini , Edson C. Silva Filho","doi":"10.1016/j.clay.2024.107539","DOIUrl":null,"url":null,"abstract":"<div><p>The processing of clay minerals consists, among other steps, in the removal of isolated mineral impurities, that is, not associated to crystalline structure of clay minerals, such as fractions of quartz and feldspars, originating from the process of soil formation. Thus, this work evaluated a sustainable method to reduction of isolated mineral impurities, in 4 <em>in natura</em> soil samples from Maranhão/Brazil, containing clay minerals. The method consisted of dispersing the samples only in water under high rotation and separating the impurities by sieving and decanting. The water and clay fraction were recovered from a manufactured solar evaporator and the clay fraction analyzed: X-ray diffraction (XRD) revealed a reduction in the intensities of mineral impurities, largely quartz, and a significant increase in the intensity corresponding to clay minerals; X-ray fluorescence (XRF) demonstrated a decrease in the SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> ratio, indicating quartz removal; Fourier transform infrared analysis (FTIR) indicated removal of organic material; thermal analysis (TG/DTG) revealed an increase in the percentage of structural water loss, suggesting an increase in clay mineral content, and adsorption/desorption isotherms of N<sub>2</sub> demonstrated an increase in the surface areas and adsorption capacity of the benefited samples. The process yields obtained demonstrated compatibility with the particle size of the samples, with more expressive results for the more clayey ones. Thus, the investigated method, low cost and sustainable, proved to be viable and effective in obtaining clay minerals with reduced presence of isolated impurities, promoting considerable improvements in their properties, and favoring various technological applications, such as adsorption, heterogeneous catalysis, synthesis of mesoporous materials, among others.</p></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"260 ","pages":"Article 107539"},"PeriodicalIF":5.3000,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Clay Science","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0169131724002874","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The processing of clay minerals consists, among other steps, in the removal of isolated mineral impurities, that is, not associated to crystalline structure of clay minerals, such as fractions of quartz and feldspars, originating from the process of soil formation. Thus, this work evaluated a sustainable method to reduction of isolated mineral impurities, in 4 in natura soil samples from Maranhão/Brazil, containing clay minerals. The method consisted of dispersing the samples only in water under high rotation and separating the impurities by sieving and decanting. The water and clay fraction were recovered from a manufactured solar evaporator and the clay fraction analyzed: X-ray diffraction (XRD) revealed a reduction in the intensities of mineral impurities, largely quartz, and a significant increase in the intensity corresponding to clay minerals; X-ray fluorescence (XRF) demonstrated a decrease in the SiO2/Al2O3 ratio, indicating quartz removal; Fourier transform infrared analysis (FTIR) indicated removal of organic material; thermal analysis (TG/DTG) revealed an increase in the percentage of structural water loss, suggesting an increase in clay mineral content, and adsorption/desorption isotherms of N2 demonstrated an increase in the surface areas and adsorption capacity of the benefited samples. The process yields obtained demonstrated compatibility with the particle size of the samples, with more expressive results for the more clayey ones. Thus, the investigated method, low cost and sustainable, proved to be viable and effective in obtaining clay minerals with reduced presence of isolated impurities, promoting considerable improvements in their properties, and favoring various technological applications, such as adsorption, heterogeneous catalysis, synthesis of mesoporous materials, among others.
期刊介绍:
Applied Clay Science aims to be an international journal attracting high quality scientific papers on clays and clay minerals, including research papers, reviews, and technical notes. The journal covers typical subjects of Fundamental and Applied Clay Science such as:
• Synthesis and purification
• Structural, crystallographic and mineralogical properties of clays and clay minerals
• Thermal properties of clays and clay minerals
• Physico-chemical properties including i) surface and interface properties; ii) thermodynamic properties; iii) mechanical properties
• Interaction with water, with polar and apolar molecules
• Colloidal properties and rheology
• Adsorption, Intercalation, Ionic exchange
• Genesis and deposits of clay minerals
• Geology and geochemistry of clays
• Modification of clays and clay minerals properties by thermal and physical treatments
• Modification by chemical treatments with organic and inorganic molecules(organoclays, pillared clays)
• Modification by biological microorganisms. etc...