Study On The Preparation Of Activated Carbon From Brown Coal And The Decolourization Properties

The brown coal is taken as raw material; the chemical activation method is applied to obtain activated carbon. The correlative problems during the preparation are worked out. And then, the activated carbon derived from brown coal is applied to dye waste water treatment process, study on the decolourization properties. First,the activation reagent is selected among the phosphoric acid, Chloride Zinc and Potassium hydroxide, and iodine adsorption value is taken as the factor to reflect the activation reagent performance, the experimental results show that the effect of the Chloride Zinc on materials performances as activation reagent is favourable than phosphoric acid and potassium hydroxide. And utilized the orthogonal experiment and single factor experiment to research correlative effect factors of the preparation of activated carbon derived from brown coal. When ZnCl₂ is taken as activation reagent, effect factors include pyrolysis temperature, pyrolysis dwell time and the concentration of activation reagent. The experimental results show that the most feasible conditions to the preparation of activated carbon is the concentration of activation reagent 3mol/L, pyrolysis temperature 750℃and the pyrolysis dwell time 90 min. The thermal analysis apparatus was utilized to study the pyrolysis characteristics of the brown coal with ZnCl₂ activation brown coal under N₂ atmosphere, the experimental results show that the three stages pyrolysis reaction appeared for ZnCl₂ activation brown coal. The performances of activated carbon derived from brown coal through chemical activation method are mainly affected by the characteristic parameters of activated carbon including the shape, the acidic and basic characteristic change and so on. The experiment shows that the shape, the acidic and basic characteristics change obviously. The porous characteristics of the activated carbon derived from brown coal can be represented through N₂ adsorption isotherm. According to pore diameter distributing curve, it can be obtained that the pore diameter of activated carbon derived from brown coal is mainly mesporous. And utilized related apparatus to measure adsorbent density, it is found that the SBET area is 747.2 m²/g, the total porous volume is 0.993 cm³/g , microporous volume is 0.196 cm³/g, average pore diameter is 2.377 nm. And then, the activated carbon derived from brown coal is applied to adsorb dye in aqueous solution. The Langmuir equation can be applied to calculate the adsorption capacity of fuchsin(e) and acid black 10 B, the results is 68.03 mg/g, 126.58mg/g for fuchsin(e) and acid black 10 B, respectively. It is obvious that the decolourization properties of activated carbon are very favorable.