SELECTIVE WATER PURIFYING SYSTEM USING "MnM" AND "FeMnM"

In the beginning of the 21 century many complaints were made by water consumers regarding a black sediment which clogged the farmers` filters. A chemical analysis showed that the black sediment is mostly composed from Manganese. Its origin was from sedimentary soil deposition at anaerobic regions. The black sediment was called "MnM". The MnM was discovered to adsorb manganese and other metals and it can be used to selectively remove arsenic from water wells.

In this project the potential of low concentrations arsenic (V) removal was tested for MnM, FeMnM and FeOOH, and compared to known values for Bayoxide, and Ghoethite. Our objectives focused on understanding of the removal and oxidation mechanism for MnM and FeMnM, and some insight on the kinetics of the process. Preliminary tests were carried out to understand the kinetics of the adsorption and to determine the time necessary to reach equilibrium state. Another experiment was made to plot Isotherms comparison was obtained for some of the methods.

Adsorption Kinetics graphs were plotted for MnM, FeMnM, Bayoxide and Ghoethite for Arsenic (V) adsorption. For each of the adsorbents a set of test were made for measuring the change in concentration of the adsorbate in the solution for 24 hours period which was found to be the proper time for equilibrium. Freundlich isotherms for all adsorbents were plotted, each isotherm constructed from experiments in which the concentration of the adsorbent was constant at each point and the As (V) concentration differed. The isotherm is for the pH values 6, 7, 8.5.

The results clearly indicated a greater adsorption efficiency of the Iron containing moiety which achieved nearly 100% removal of As(V).