Papers by Keyword: Clinoptilolite

Abstract: This study investigates the impact of chemical and thermal activation on the sorption capacity of Transcarpathian clinoptilolite from the Sokyrnytsky deposit. The chemical activation of natural clinoptilolite was performed using aqueous solutions of 5% HCl and 25% H₂SO₄ at a solid-to-liquid phase ratio of 1:10. Thermal activation was conducted at a temperature of 300°C. The sorption capacity of both natural and activated clinoptilolite was evaluated for water vapor in this thermal analysis. The ability of activated clinoptilolite to absorb direct blue dye was determined through spectrophotometric analysis. The partial degradation of clinoptilolite due to acid modification was confirmed by X-ray phase analysis and electron microscopy. The sorption isotherms of direct blue dye were modeled using the Langmuir equation, and the corresponding constants were determined. Clinoptilolite activated with a 25% aqueous H₂SO₄ solution is recommended for use in sorption technologies for wastewater treatment from direct dyes.

Abstract: The ionic mechanism of copper ion sorption from an aqueous medium has been confirmed. The study has elucidated the regularities of the process within a stirred bed reactor, where kinetics are limited by the internal diffusion region. Initial sorption curves under dynamic conditions have been obtained.

Abstract: The aim of the study is to research of the adsorption properties of heavy metal ions Pb²⁺, Cd²⁺ and Ni²⁺ from industrial wastewater. For the adsorption of heavy metal ions, natural clinoptilolite was used, which belongs to the Ai-Dag deposit of the Tovuz-Kazakh region of Azerbaijan. Isotherms and kinetic curves of adsorption of heavy metal ions Pb²⁺, Cd²⁺ and Ni²⁺ were determined. The dependence of the adsorption of heavy metal ions on the pH value is also shown. It was revealed that the separation process proceeds more intensively at pH values ​​of 5-6. It has been established that the maximum adsorption capacity of the clinoptilolite adsorbent for adsorption of Pb²⁺, Cd ²⁺ and Ni²⁺ ions is 7.5, 6.7 and 5.9 mmol/g, respectively.

Abstract: The sorption method of purification of flushing water from non-ferrous metal ions in galvanizing-bath rooms of mechanical facilities was investigated, which is one of the most realistic ways to solve the problem of environmental protection from such pollution. The effect of preliminary thermal and chemical modification of the crystal structure in order to improve the sorption capacity of clinoptilolite was established. The kinetics of the copper ion exchange process on clinoptilolite in static conditions was determined.

Abstract: Natural clinoptilolite (N-CLI) and N-CLI based solid-state compositions containing copper(II) chloride and halide ions (X^- = Cl^-, Br^- or I^-) were investigated by X‑ray diffraction phase analysis, IR spectroscopy, thermogravimetry, water vapour adsorption, and pH‑metry. After that, they were tested in the reaction of low-temperature sulphur dioxide oxidation with air oxygen. It has been found that N-CLI has no protective properties in respect of sulphur dioxide whereas CuCl₂‑KX/N-CLI compositions have the significant protective activity in the process of air purification from sulphur dioxide increasing in the order Cl^- < Br^- < I^-.

Abstract: The removal and recuperation of copper from the residual liquors of galvanic industry by ion exchange have been studied using the natural clinoptilolite and mordenite zeolites from different deposits of Russia and Georgia.

Abstract: In this study, adsorption of binary metal (Ni(II) and Pb(II)) ions from aqueous solution by using natural (NC), acid-modified (AC) and base-modified (BC) clinoptilolite were investigated to determine the effects of adsorbent dosage, metal solution’s pH and initial metal solution concentration. From the adsorption studies, the optimum dosage of adsorbent was found to be 2.0g for all adsorbents (NC, AC and BC) specifically for removal of Pb(II). In contrast, optimum dosage of for removal of Ni(II) was found to be 2.0g for NC and 4.0g for both AC and BC, respectively. The average pH for Ni(II) and Pb(II) ion solutions were 6. It was further observed that, the percentage removal of Ni(II) was largely influenced by the presence of lead due to the preference of Pb²⁺ ions by the natural and modified clinoptilolites.

Abstract: Natural clinoptilolite (Cli) and chabazite (Cha) were used as the carrier for two types of antibacterial agents: cetylpyridinium chloride (CPC) and silver cations (Ag). CPC-zeolites, Ag-zeolites and CPC-Ag-zeolites were characterized by Energy Dispersive X-ray (EDX) analyzer and Fourier Transform Infrared (FTIR) spectroscopy and proved the attachment of CPC molecules on Ag-zeolite in CPC-Ag-zeolite samples. The determination of Minimum Inhibition Concentration (MIC) against P. aeruginosa and B. subtilis in saline solution and distilled water was performed to observe the effect of chloride ions on the antibacterial activity of the studied samples. From the MIC values, a new modified zeolite with CPC and Ag (CPC-Ag-zeolites) showed better antibacterial activity compared to that of CPC-zeolites and Ag-zeolites and performed well in both saline solution and distilled water.

Abstract: Three different zeolites (erionite, mordenite and natural clinoptilolite) were used to study influence of zeolite topology on the state of copper during ion-exchange and following reduction in hydrogen flow. This comparative study clearly demonstrates the influence of used zeolite matrices on the process of implantation of copper nanospecies. Starting from the ion-exchange, the alterations in the state of Cu²⁺ ions start to be evident due to variations of the intensity of charge transfer band. Copper ions start to reduce at specific temperatures depending on the type of zeolite matrix. Copper plasma resonance band change its shape and position for different zeolites. In the case of Cu-CLI samples this band change both the shape and position for different temperature of reduction. These observations permit to suggest that the mechanism of copper ion reduction and agglomeration to form copper nanoparticles noticeably depend on the type of zeolite matrix. This mechanism is more complex for the Cu CLI than for the Cu-MOR and Cu-ERI systems. Copper nanoparticles formed at low temperatures in the case of Cu-CLI samples undergo changes while temperature of reduction grow.

Abstract: This experiment use natural clinoptilolite powder as main materials to prepare the large specific surface and high porosity spherical compound filter material by adding adhesive and pore-forming agent etc.This compound filter material has favourable effect when treating sanitary wastewater. The static adsorption test showed that the absorption ratio of ammonia-nitrogen is 58.5% when the compound filter material dosage was 100g/L, NH4+-N concentration was 100mg/L and the contact time was 40min.The cure fitting of the adsorption isotherm of NH4+-N on the compound filter material could be well described by the Langmuir formula and R2 (the coefficient of determination) is 0.99216. At the stably running phase, when the average concentrations of influent NH3-N was 35mg/L, the average removal ratio and concentration of effluent NH4+-N reached 83.51% and 5.81mg/L which could meet the first degree of national wastewater discharge standard (GB 8978-1996).