Waldemar Pichór

Use of clinoptilolite for the immobilization of heavy metal ions and preparation of autoclaved building composites

The work presents the results of application of natural clinoptilolite for immobilization of heavy metal cations (Ag(+), Pb(2+), Cd(2+) and Cr(3+)) from aqueous solutions and uses zeolite to prepare autoclaved building composites. Sorption has been conducted on sodium form of natural clinoptilolite originated from Poland. Clinoptilolite (sodium form containing heavy metal cations) has been applied to obtain new building materials which have good physical properties. Samples produced by autoclaving process showed relatively low bulk density (about 1.35 g/cm(3)). The compressive strength depended on the amount of CaO in the initial mixture. Its maximum value was about 40 MPa. The influence of heavy metal cations on the compressive strength values was insignificant (except for the Cr(3+) ions). However, all the cations modified the microstructure and the ordered state of C-S-H phase. Efficiency of Ag(+), Cd(2+) and Pb(2+) ions immobilization on the mineral matrix was shown. In the work, results of IR spectroscopy, atomic absorption spectroscopy (AAS) studies, X-ray diffraction analysis, SEM observations and technological investigations are presented.

Low-temperature synthesis of zeolite from perlite waste — Part I: review of methods and phase compositions of resulting products

In this paper a review of the recent studies on the synthesis of zeolites from expanded perlite under hydrothermal conditions is presented. Attention is paid to possible outcomes of synthesis from low cost glass material, such as perlite. The study also investigates the phase composition of zeolitic materials obtained by modification of by-product derived from an expanded perlite production process. The synthesis was made using the hydrothermal method with sodium hydroxide under autogenous pressure at a temperature below 100 °C for 1 to 72 h. It was possible to obtain a zeolitic material at a temperature as low as 60 °C using 4.0 M NaOH. The X-ray diffraction pattern showed the biggest peak intensity of zeolite X with 4.0 M NaOH at the temperature of 70 °C. During synthesis at higher temperature zeolite Na-P1 (with 3.0 M NaOH at 90 °C) and hydroxysodalite (with 5.0 M NaOH at 90 °C) were obtained.

PROPERTIES OF FIBER REINFORCED CEMENT COMPOSITES WITH CENOSPHERES FROM COAL ASH

Cenospheres are lightweight, thin-walled hollow spheres which are by-products of the combustion of pulverized coal at thermal power plants. Due to their properties they are a potentially interesting filler and may be used for lightweight cement-based composites production. Several works show that the cement based composites with addition of cenospheres have good properties. These researches are focused on the properties of such composites with addition of relatively large amount of synthetic fibers. The main effect is manifested by an improvement of flexural behavior after cracking of cement matrix. The results of studies concerning the fiber reinforced cement composites with cenospheres as filler up to 60% of volume are presented in this paper. The influence of cenospheres content on the main mechanical properties (flexural strength, modulus of rupture), water sorption and thermal conductivity of fiber reinforced cement composites with different types of fibers is shown. The SEM observations of interfacial zone between cenosphere-cement matrix and fiber-cement matrix are presented. The results show that an usage of the cenospheres as lightweight filler may be a way to obtain fiber reinforced cement composites of low or moderate density.

Low-temperature synthesis of zeolite from perlite waste — Part II: characteristics of the products

The paper investigates the properties of sodium zeolites synthesized using the hydrothermal method under autogenous pressure at low temperature with NaOH solutions of varying concentrations. During this modification, zeolites X, Na-P1 and hydroxysodalite were synthesized. The synthesis parameters, and thus, phase composition of resulting samples, significantly affected the specific surface area (SSA) and cation exchange capacity (CEC). SSA increased from 2.9 m2/g to a maximum of 501.2 m2/g, while CEC rose from 16 meq/100 g to a maximum of 500 meq/100 g. The best properties for use as a sorbent were obtained for perlite waste modified with 4.0 M NaOH at 70 °C or 80 °C.

Electric and thermoelectric properties of cement composites with expanded graphite

The electric resistance and thermoelectric properties of cement composites with addition of expanded graphite were. The expanded graphite was obtained from intercalated graphite by rapid heating in different conditions. The influence of thermal treatment on thermoelectric properties was measured. The cement pastes were prepared in the two different ways, either by mixing together expanded graphite and cement, or by rubbing compounds together in order to obtain smaller particles of graphite (even nanometric size) during mixing. The bulk density and electric and thermoelectric properties of cement pastes with addition of expanded graphite were measured. The results of investigations show that the electric properties of composites are strongly influenced by the conditions of thermal expansion as well as by the technique of preparation.

Properties of Clinoptilolite Based Autoclaved Composites

Abstract Among several available methods of removing heavy metal cations from wastewater, the sorption method with use of zeolite appears to be encouraging. Clinoptilolite, which is a naturally occurring zeolitic pozzolana, shows ion exchange properties and is mainly used for immobilization of very different wastes, e.g. heavy metal cations. The investigated Polish natural zeolite deposit contains about 20-25 wt. % of clinoptilolite and considerable amounts of different phases: quartz, smectite, metal oxides, and others. Before application as a matrix for metal uptake from wastewater the zeolite should be concentrated and pre-treated as to increase its sorption capacity. Very important problem after ion sorption and immobilization is solidification of zeolite in durable form like mortar, concrete or another. Sorption of heavy metal cations (Pb(II), Cr(III), Cd(II), Zn(II)) from aqueous solutions on clinoptilolite was studied using atomic absorption spectrometry (AAS) and FT-IR spectroscopy. The results of physical properties investigation of the clinoptilolite based composites obtained during autoclaving process with different amount of lime at 180°C are shown. The comparison between results obtained for materials containing initial clinoptilolite and zeolite after sorption process are presented. The paper describes results of structural studies (IR spectroscopy, XRD analysis and SEM observations) of zeolites on which sorption of various metal cations has been carried out. Obtained results indicate that the proposed method of solidification the clinoptilolite based materials after heavy-metal uptake is promising and applicable in simple way in Autoclaved Aerated Concrete technology or production of Calcium Silicate blocks.

The Influence of Waste Expanded Perlite on Chemical Durability of Mortars

Degradation of building materials is an important phenomena influencing its design and utilization. Corrosion of concrete, due to common use of this material is especially important. Chemical corrosion of cementitous materials may be mitigated using various methods. Among them introduction of properly chosen active supplementary cementitous materials to the mix is one of most commonly used. One of possible additives possessing pozzolanic properties is ground waste expanded perlite. No data on the influence of such perlite on chemical durability of cementitous materials can be found in literature. Present paper presents results of investigation on the influence of ground waste expanded perlite on chemical durability of cement mortars. Results obtained showed that there is an improvement of durability of mortars modified with ground waste expanded perlite in sodium sulfate enviroment.