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The aim of this work is to investigate the application of fly ash adsorbent for removal of arsenite ions from dilute solution (100-1,000 ppm). Experiments were carried out using material from the "Turów" (Poland) brown-coal-burning power plant, which was wetted, then mixed and tumbled in a granulator to form spherical agglomerates. Measurements of arsenic adsorption from aqueous solution were carried out at room temperature and natural pH of fly ash agglomerates, in either a shaken flask or circulating column, to compare two different methods of contacting solution with adsorbent. Adsorption isotherms of arsenic were determined for agglomerated material using the Freundlich equation. Kinetic studies indicated that sorption follows a pseudo-second-order model. Preferable method to carry out the process is continuous circulation of arsenite solution through a column.

The scope of this contribution was to investigate in detail an application of fly ash adsorbent for the removal of arsenite ions from a dilute solution. The experiments have been carried out using fly ash from black coal burning power plant "Siersza" and brown coal burning power plant "Turów" (Poland), which was wetted, then mixed and tumbled in the granulator with a small amount of cement to increase the mechanical strength of agglomerates. The measurements of arsenic adsorption from the aqueous solution were carried out in the flask (with shaking), as well as in the column (with circulation), in order to compare two different methods of contacting waste with adsorbent. The adsorption isotherms of arsenic were determined for granulated material, using the Freundlich model. Kinetics studies indicated that the sorption follows a pseudo-first-order (PFO) model (Lagergren) and the Elovich-type model.

Applying the coagulation and reverse osmosis for water recovery from evaporative water. Evaporative water from the concentration of yeast slurry is a potential raw material for water recovery. It is characterized by low pH (4.6-6.3), increased turbidity (3.65-13.7 NTU), and high content of total organic carbon (356-754 mg/L). Its treatment in the volume coagulation process using NaOH and coagulant PIX 111, was studied. Water turbidity was lowered to a value below 1 NTU, but coagulation did not allow for the removal of organic compounds. Coagulation was effective at temperatures of 20 and 40°C. Pretreatment of the feed water for RO included alkalization, coagulation, sedimentation, and 5 μm fine filtration (variant I), as well as single 5 μm fine filtration (variant II as a blank). In variant I the feed with improved properties was achieved. Membrane filtration allowed for effective desalination of evaporative water, 98 and 73% conductivity retention was obtained, depending on the method of the feed pre-treatment. The organic compounds were removed less efficiently, at 94 and 84%, respectively.

a b s t r a c tIn this study the commercially available chelating ion exchanger Lewatit TP 260 modified for the effective sorption was used for removal of Cu(II), Zn(II) and Ni(II) ions from aqueous acidic solutions. During the modification the resin was converted into Na + or 2Na + form. It was found that different conditions such as pH, concentration and form of the functional groups affect the sorption efficiency of the aminophosphonate resin towards the above-mentioned heavy metal ions in aqueous solutions at a low pH value. The maximum sorption capacity of Lewatit TP 260 towards Cu(II), Zn(II) and Ni(II) was obtained for the 2Na + form. The sorption kinetic data were found to fit the pseudo-second-order model as compared with the pseudo-first-order model. The intraparticle diffusion model suggested that the sorption process was dominated by the external mass transfer of Cu(II), Zn(II) and Ni(II) ions to the surface of Lewatit TP 260 with the aminophosphonate functional groups in the 2Na + form.