Mechanism of Chromium Separation and Concentration from Tannery Wastewater by Membrane Methods.

The article specifies conditions for a nanofiltration process employing a diafiltration method with a constant volume diafiltration (NF-CVD) for exhausted chromium tannery wastewater treatment and describes a mechanism of the examined process carried out for model wastewater. The authors prove that a decrease in salt concentration in the NF-CVD process is an important factor that enables effective concentration of chromium. Based on the proposed chromium separation and concentration mechanisms, it was found that this effect may be achieved by (1) limiting the formation of an ionic adsorption-polarization layer and (2) reducing the increase in the osmotic pressure caused by a change in the separation properties of the membrane.

Consequences of the accessibility of the mountain national parks in Poland.

In Poland, mountain national parks are visited by about 8 million tourists annually. As a result, national parks must have a properly developed infrastructure to accommodate such a large number of people. Tourism development in mountain national parks satisfies the needs of tourist participants and should increase the attractiveness of the area, fit into the cultural concepts of a given region, and promote its development.

Kinetics of chromium(III) transport through a liquid membrane containing DNNSA as a carrier.

Kinetics of Cr(III) ions transport through a bulk liquid membrane containing dinonylnaphthalenesulfonic acid (DNNSA) as a carrier, flowing over aqueous phases, has been examined. Special attention has been paid to the effect of the membrane's velocity flow on the chromium concentration decrease in a feed phase. For the description of relationships of chromium(III) concentration in particular phases with the time, a model based on the assumption of consecutive first-order reactions was proposed.