Synthesis and Modification of Clinoptilolite

Ambrožová, Pavlína; Kynický, Jindřích; Urubek, Tomáš; Nguyen, Vinh Dinh

doi:10.3390/molecules22071107

Cited by 61 publications

(42 citation statements)

References 78 publications

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“…Porous parameters of our modified delivery clinoptilolite systems were evaluated using N 2 -sorption analysis to assess the porous features of the hosts and pore size distribution curves to assess the pore size homogeneity and sizes. These were in close agreement with previously published studies on bimodal porous feature of the clinoptilolite [ 9 , 10 , 39 ]. Typical surface areas and pore volumes were obtained for both of our monocationic NaCLI and HCLI matrices, but as expected, these values were lower for NaCLI matrix, which explained the lower loading degree of BCNU.…”

Section: Discussionsupporting

confidence: 93%

“…Clinoptilolite is a microporous mineral component of a volcanic rock from the group of natural zeolites that has been extensively tested as a chelating agent or as an adjuvant in cancer therapy, because of its cation exchanging and chelating properties [ 6 , 7 ]. Previously published studies on clinoptilolite confirmed the bimodal porous feature of this material [ 8 , 9 , 10 ].…”

Section: Introductionsupporting

confidence: 68%

“…Clinoptilolite was used either in its initial form or in modified form. Single or multiple step modifications of clinoptilolite by various chemical reagents gave specific properties that extended the field for medical use [ 10 ].…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Inhibition of bcl-2 and cox-2 Protein Expression after Local Application of a New Carmustine-Loaded Clinoptilolite-Based Delivery System in a Chemically Induced Skin Cancer Model in Mice

et al. 2017

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Our research has focused on in vitro and in vivo evaluations of a new Carmustine (BCNU)-loaded clinoptilolite-based delivery system. Two clinoptilolite ionic forms—hydrogen form (HCLI) and sodium form (NaCLI)—were prepared, allowing a loading degree of about 5–6 mg BCNU/g of zeolite matrix due to the dual porous feature of clinoptilolite. Clinoptilolite-based delivery systems released 35.23% of the load in 12 h for the BCNU@HCLI system and only 10.82% for the BCNU@NaCLI system. The BCNU@HCLI system was chosen to develop gel and cream semisolid dosage forms. The cream (C_BCNU@HCLI) released 29.6% of the loaded BCNU after 12 h in the Nylon synthetic membrane test and 31.6% in the collagen membrane test, higher by comparison to the gel. The new cream was evaluated in vivo in a chemically induced model of skin cancer in mice. Quantitative immunohistochemistry analysis showed stronger inhibition of B-cell lymphoma-2 (bcl-2) and cyclooxygenase 2 (cox-2) protein expression, known markers for cancer survival and aggressiveness, after the treatment with C_BCNU@HCLI by comparison to all the control treatment types, including an off-label magistral formula commercially available Carmustine cream as reference, bringing evidence that a clinoptilolite-based delivery systems could be used as a cancer drug carriers and controlled release systems (skin-targeted topical delivery systems).

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Section: Discussionsupporting

confidence: 93%

Section: Introductionsupporting

confidence: 68%

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Inhibition of bcl-2 and cox-2 Protein Expression after Local Application of a New Carmustine-Loaded Clinoptilolite-Based Delivery System in a Chemically Induced Skin Cancer Model in Mice

et al. 2017

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“…The synthetic zeolites were produced according to Mackinnon, Millar and Stolz 16 , granulated according to procedure described in Table 1. Clinoptilolite had a Si/Al = 4.0 (natural zeolites were reported to have a Si/Al = 3-5 11,32,33 ) while lower values of Si/Al (1.5-2.0) were measured for the synthetic zeolites ( Table 1). The zeolites were initially washed with deionized water to remove any dust from their surface and sieved to obtain the required size (1-2 mm for the synthetic zeolites and 2.5-3.5 mm for the clinoptilolite) before further tests.…”

Section: Methodsmentioning

confidence: 96%

Preparation and evaluation of zeolites for ammonium removal from municipal wastewater through ion exchange process

Guida

Potter²,

Jefferson

et al. 2020

Sci Rep

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the application of ion exchange process for ammonium (nH 4 +-n) removal from wastewater is limited due to the lack of suppliers of engineered zeolites which present high ammonium exchange capacity (Aec) and mechanical strength. this study focuses on the preparation and evaluation of synthetic zeolites (Zeolite1-6) by measuring AEC and resistance to attrition and compression, against natural (clinoptilolite) and engineered zeolite (reference, Zeolite-n). At high nH 4 +-N concentrations, Zeolite6 and Zeolite2 showed capacities of 4.7 and 4.5 meq NH 4 +-N/g media, respectively. In secondary effluent wastewater (initial nH 4 +-N of 0.7 meq NH 4 +-N/L), Zeolite1, 2 and 6 showed an AEC of 0.05 meq NH 4 +-N/g media, similar to Zeolite-N (0.06 meq NH 4 +-N /g media). Among the synthetic zeolites, Zeolite3 and 6 showed higher resistance to attrition (disintegration rate = 2.7, 4.1 NTU/h, respectively) when compared with Zeolite-N (disintegration rate = 13.2 NTU/h). Zeolite4 and 6 showed higher resistance to compression (11 N and 6 N, respectively). Due its properties, Zeolite6 was further tested in an ion exchange demonstration scale plant treating secondary effluent from a municipal wastewater treatment plant. However, Zeolite6 disintegrated after 2 months of operation, whilst Zeolite-N remained stable for 1.5 year. This highlighted the importance of the zeolite's mechanical strength for successful application. in particular, future work should focus on the optimization of the zeolite production process (temperature, time and dimension of the kiln during calcination) to obtain an engineered zeolite with a spherical shape thus reducing eventual sharp edges which can affect mechanical strength.

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“…Clinoptilolite is one of the predominant natural species of zeolites and has been successfully used for contaminant removal [15,44]. This mineral belongs to the heulandite group and comprises a two-dimensional channel system (a 10-ring system (0.31 nm × 0.75 nm), an 8-ring system (0.36 nm × 0.46 nm) and channels (0.28 nm × 0.47 nm) [45].…”

Section: Introductionmentioning

confidence: 99%

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

Rocha

Zuquette

2020

Geosciences

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The purpose of this work is to evaluate the capacity of a natural zeolite to be used as a reactive material in a permeable reactive barrier (PRB) to remove inorganic contaminants from groundwater. To this aim, zeolite samples were subjected to characterization tests, column experiments, batch tests and a flushing process to evaluate the adsorption and desorption capacities of the zeolite. In the column experiments, the samples were subjected to eight successive cycles involving the percolation of a potassium aqueous solution (1500 mg/L) and a subsequent flushing process with water. Batch tests were conducted by mixing 20 g of zeolite with 100 mL of single-element aqueous solutions of K and Zn with concentrations of 200 mg/L. The results indicate that the zeolite rock is composed predominantly of clinoptilolite species and has a Si/Al ratio of 6.8, a high cationic exchange capacity (CEC) of 180 cmolc/kg and a high K+ adsorption rate with a removal efficiency of 78%. The adsorption isotherms of the zeolite follow the Langmuir model and are well fit by a pseudo-second-order kinetic model showing a high correlation coefficient (r2 > 0.999) for both K+ and Zn2+ cations. Additionally, the contaminant transport parameters for K+ ions (Rd = 24.9; Dh = 1.32 × 10–2 cm2/s and α = 1.42) reveal that the zeolite is resistant to the dispersion of ions in the barrier, indicating that the material has advantageous characteristics for use in a PRB. However, the flushing process of the material is not efficient, indicating that the appropriate use of the zeolite is in clean-up systems in which the adsorbent material can be exchanged after losing its efficiency as a reactive barrier.

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Synthesis and Modification of Clinoptilolite

Cited by 61 publications

References 78 publications

Inhibition of bcl-2 and cox-2 Protein Expression after Local Application of a New Carmustine-Loaded Clinoptilolite-Based Delivery System in a Chemically Induced Skin Cancer Model in Mice

Inhibition of bcl-2 and cox-2 Protein Expression after Local Application of a New Carmustine-Loaded Clinoptilolite-Based Delivery System in a Chemically Induced Skin Cancer Model in Mice

Preparation and evaluation of zeolites for ammonium removal from municipal wastewater through ion exchange process

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

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