Paper Title
Synthesis and Evaluation of Porous Adsorbents from Oak Sawdust in the Remotion of Colorants

Abstract
The dietary, textile, cosmetic, pharmaceutic, paper, plastic, paint, and leather industries, are the main sources of liquid residues with dyes; these industrial effluents end up polluting the rives and underground water sources. The large quantities of synthetic dyes, aside sulphates and nitrates disposed into the slopes cause the diminution of the oxygen into the aquatic ecosystems, for that matter provoke the eutrophication; the above, worsened considering that more than 700.000 ton of dyes are produced each year in the word and increasingly used in diverse industrial sectors. Thus, in the present investigation the use of biochar prepared from oak sawdust tree (Quercus alba), modified by an activation with phosphoric acid (H3PO4) and functioned with urea at different concentration (1, 3 and 6 M) are presented as an alternative; by evaluating the adsorption capacity varying pH (7, 8, and 9). The activated biochar functionalized with urea at concentration 6 M (CR6M) presented the best characteristics for dyes adsorption, showing that the adsorption capacity of methylene blue augmented 39 % with the pH, reaching 16.768 mg/g. It is concluded that the oak tree sawdust is a good precursor for the synthesis of porous adsorbents-carbon type used in the removal of colorants. Keywords - Activated Carbon, Blue Methylene, pH effect.