Clinoptilolite

Zeolites are tire product of a hydrotliennal conversion process [28]. As such tliey can be found in sedimentary deposits especially in areas tliat show signs of fonner volcanic activity. There are about 40 naturally occurring zeolite types. Types such as chabazite, clinoptilolite, mordenite and phillipsite occur witli up to 80% phase purity in quite large... 

Ammonium Ion Removal. A fixed-bed molecular-sieve ion-exchange process has been commercialized for the removal of ammonium ions from secondary wastewater treatment effluents. This application takes advantage of the superior selectivity of molecular-sieve ion exchangers for ammonium ions. The first plants employed clinoptilolite as a potentially low cost material because of its availability in natural deposits. The bed is regenerated with a lime-salt solution that can be reused after the ammonia is removed by pH adjustment and air stripping. The ammonia is subsequentiy removed from the air stream by acid scmbbing. 

SORBENTS FOR CONCENTRATION OF Pd(II) NATURAL AND ACIDIC MODIFIED TRANSCARPATHIAN CLINOPTILOLITE... 

Clinoptilolite is microporous crystalline solid with well-defined structure, which have great potential for a number of applications in various fields, such as adsorption, separation, ion-exchange and catalysis. 

For example. Date et al. (1983) recognized the following alteration zones in the Fukazawa Kuroko mine area of Hokuroku district from the centre (near the orebody) to the margin (1) sericite-chlorite zone (zone 111 in Figs. 1.20-1.22) characterized by quartz + sericite Mg-rich chlorite (2) montmorillonite zone (zone 11 in Fig. 1.20) characterized by Mg-Ca-type montmorillonite + quartz kaolinite calcite sericite Fe-rich chlorite and (3) zeolite zone (zone 1 in Fig. 1.20) characterized by clinoptilolite + mordenite + Mg-Na-type montmorillonite cristobalite calcite or analcime + Mg-Na-type montmorillonite + quartz calcite sericite Fe-rich chlorite (Fig. 1.20). 

Teague Mineral Products, Salem, Evaluating the naturally occurring mineral OR clinoptilolite for removal of lead from... 

The process is best shown by example. Suppose that we wish to balance the reaction by which calcium clinoptilolite (CaAl2Siio024 8H2O), a zeolite mineral, reacts to form muscovite [KAl3Si30io(OH)2] and quartz (Si02). We choose to write the reaction in terms of the aqueous species Ca++, K+, and OH-. 

Reserving clinoptilolite for the reaction s left side, we write the stoichiometry of each remaining species in matrix form,... 

To balance a reaction, we write swap reactions relating B to B. Returning to the previous example, we wish to compute the reaction by which Ca-clinoptilolite transforms to muscovite and quartz. Reserving the clinoptilolite for the reaction s left side, we write the swap reactions for the basis transformation in matrix form. 

The inverted matrix is the transformation matrix for the basis we have chosen. The reaction in the LLNL database for Ca-clinoptilolite,... 

Fig. 22.3. Mineralogical results (top) of mixing cold seawater into one kg of hot hydrothermal fluid from the NGS field. Minerals present in volumes less than 0.01 cm3 are not shown. These minerals, in order of decreasing abundance, are sphalerite, barite, potassium mor-denite, calcium clinoptilolite, and covellite. Also shown (bottom) is the temperature of the fluid during mixing.

Fig. 23.6. Calculated saturation indices (log Q/K) of aluminum-bearing minerals plotted versus temperature for a hot spring water from Gjogur, Hveravik, Iceland. Lines for most of the minerals are not labeled, due to space limitations. Sampling temperature is 72 °C and predicted equilibrium temperature (arrow) is about 80 °C. Clinoptilolite (zeolite) minerals are the most supersaturated minerals below this temperature and saponite (smectite clay) minerals are the most supersaturated above it.

The analysis for Namafjall well 8 is similar to that of the Hveragerdi well in that a number of Ca, Mg, and Fe-bearing minerals appear supersaturated over the temperature range of interest. Again, this result probably reflects mixing or contamination. The equilibrium temperatures for quartz, albite, potassium feldspar, potassium clinoptilolite, and muscovite (Fig. 23.10) bracket a relatively broad temperature range of 205 °C to 250 °C, which can be compared to the well s inflow temperature of 246 °C. In this case, the equilibrium temperature is notably less well... 

Viani, B. E. and C. J. Bruton, 1992, Modeling ion exchange in clinoptilolite using the EQ3/6 geochemical modeling code. In Y. K Kharaka and A. S Maest (eds.), Water-Rock Interaction. Balkema, Rotterdam, pp. 73-77. 

STUDY OF THE CLINOPTILOLITE-RICH TUFF-BASED COMPOSITES FOR SOME AQUEOUS ANIONIC SPECIES RECOVERY... 

Key words Clinoptilolite, ODA-modifier, chromate and arsenate removal, adsorption, isotherm, and breakthrough curve. 

Organo-modified natural zeolites as new tailored natural materials for removal of cations, anions and even organic pollutants may present fairly large potential for water utility companies. The topic of this study was to examine the oxyanions removal from waters by octadecylammonium-enriched inland clinoptilolite. The 18-carbon chain consisting surfactant attached on the clinoptilolite surface, as to the organic acids of living bodies comparable substances, makes the treatment process economic on scale and cost-effective as well.7... 

X-ray diffraction measurements indicated that the zeolite rock consisted primarily of clinoptilolite (60-70%), volcanic glass (10%), feldspar (10%) and minor quantities of cristobalite, quartz and plagioclase (20%). Fig. 1 represents the XRD pattern of ODA-Clinoptilolite-rich tuff used for arsenate or chromate removal from aqueous solutions. 

Figure 1. XRD pattern of ODA-modified clinoptilolite-rich tuff adsorbed with arsenate (chromate)...

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