Evaluation of Zeolite as a Potential Reactive Medium in a Permeable Reactive Barrier (PRB): Batch and Column Studies

Exploring the Properties of Micronized Natural Zeolitic Volcanic Tuff as Cosmetic Ingredient

This study explores the characteristics of a micronized natural zeolitic volcanic tuff (MZ) as ingredient in cosmetic formulations. In particular, the purpose was to prepare and investigate the organoleptic and physicochemical properties of two representative cosmetic formulations containing MZ. The MZ samples were characterized using X-ray fluorescence (XRF), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. pH, cation exchange capacity (CEC), apparent density, chemical composition and particle size distribution of MZ samples were also determined. The micronization treatment applied did not produce significant structural and physicochemical changes with respect to the raw zeolitic volcanic tuff. The prepared formulations containing 5% MZ with different particle sizes (100–125 µm and 125–250 µm) were subjected to preliminary and accelerated stability tests, and the pH and organoleptic properties were also evaluated. The cosmetic formulations presented a pH of 4.3, a pleasant touch, good spreadability, easy application on skin, no color alteration and a good stability after 15, 30 and 60 days of storage at room temperature, low temperature and freezer during the accelerated stability tests. The obtained results endorse the MZ as suitable for the development of formulations exploiting the clinoptilolite properties as a cosmetic ingredient.

Suitability Zoning for Sustainable Drainage Systems (SuDSs): Application in a Basin in Southern Brazil

The objective of this study was to propose a set of procedures to assess areas regarding the suitability of sustainable drainage systems (SuDSs) with application in a basin in the urban area of São Carlos (Brazil). The assessment was based on an analysis of 39 attributes reflecting the infiltration conditions that control the functional and constructive aspects of the systems, including subsurface drainability, stability, and groundwater contamination potential, which control the degree of suitability of each plot of land. The data obtained through engineering geological mapping procedures and physical principles were used to characterize the area, which resulted in the division of the basin into five SuDS suitability zones, ranging from favorable to restrictive. The proposed procedures proved to be efficient for analyzing the suitability of different SuDS types and the zoning of an area into terrain units. This approach can help planners identify the most appropriate SuDS types for a given unit, optimize the efficiency/cost relationship, and foresee potential environmental and construction-related challenges. In other words, this procedure enables the assessment of the suitability of SuDSs for different unit terrain types with inexpensive and environmentally efficient technological procedures and resources and can be applied at a fine geographic scale.

An overview of in-situ remediation for nitrate in groundwater

Faced with the increasing nitrate pollution in groundwater, in-situ remediation has been widely studied and applied on field-scale as an efficient, economical and less disturbing remediation technology. In this review, we discussed various in-situ remediation for nitrate in groundwater and elaborate on biostimulation, phytoremediation, electrokinetic remediation, permeable reactive barrier and combined remediation. This review described principles of each in-situ remediation, application, the latest progress, problems and challenges on field-scale. Factors affecting the efficiency of in-situ remediation for nitrate in groundwater are also summarized. Finally, this review presented the prospect of in-situ remediation for nitrate pollution in groundwater. The objective of this review is to examine the state of knowledge on in-situ remediation for nitrate in groundwater and critically evaluate factors which affect the up-scaling of laboratory and bench-scale research to field-scale application. This helps to better understand the control mechanisms of various in-situ remediation for nitrate pollution in groundwater and the design options available for application to the field-scale.

New Deposit of Mordenite-Clinoptilolite in the Eastern Region of Cuba: Uses as Pozzolans

This work describes the newly discovered zeolites in the eastern region of Cuba. In the researched area, there have been no previous studies of natural zeolite exploration. Therefore, the results shown here are new. The main object of this research is to analyse five samples of zeolites and demonstrate their pozzolanic capacity and the possibility of their usage in the industrial manufacturing of pozzolanic cements. The study of the samples was performed by X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM). A chemical analysis (CAQ) to determine the quality of the samples as pozzolans was performed, by determining the total SiO₂, reactive SiO₂, total CaO, reactive CaO, Al₂O₃, MgO and the insoluble residue (I.R.). Lastly, an eight-day pozzolanicity analysis (PA) was carried out to determine the pozzolanic reactivity of the samples. The results obtained by XRD, XRF and SEM established that the researched zeolite samples have two main zeolitic phases: mordenite and clinoptilolite. Altered volcanic glass, quartz and smectite (montmorillonite) are the secondary phases. The results of the chemical quality analysis (CAQ) showed that the samples contain a considerable amount of reactive SiO₂ and reactive CaO, as well as a low content of insoluble residue, which reinforces their properties as pozzolans. The results of the pozzolanicity analysis (PA) concluded that the analysed samples actively react with Ca(OH)₂ after eight days. Based on all the results mentioned above, it is established that both mordenite and clinoptilolite behave like pozzolans and can be recommended for the manufacture of pozzolanic cements, which have more effective properties than Portland cement, in terms of physical, chemical and mechanical strength, low heat of hydration, resistance to sulphates, low CO₂ emissions to the atmosphere and negligible impacts on the environment.