Academic Research On Adsorbent Derived From Sewage Sludge Based On Chemical Activation Method And Its Application

The residual sewage sludge produced through biologic method treatment domestic sewage is taken as raw material, based on the disadvantages of all kinds of traditional sewage sludge treatment, the chemical activation method is applied to paralysis sewage sludge to obtain porous adsorption materials. The correlative problems during the preparation are worked out. And then, the adsorbent derived from sewage sludge is applied to the sulfur dioxide and metal ions treatment process, and the concerned conditions are worked out during the applications, and developed a new process for sewage sludge resource application.The key factor is the selection of the chemical activation reagent during the adsorbent preparation through the chemical activation method. The activation reagent is selected among the Phosphoric acid, Sulphuric acid, Chloride Zinc and Potassium hydroxide, and Sbet, iodine adsorption value and methylene blue adsorption value are taken as the factors to reflect the activation reagent performance, the experimental results show that the effect of the phosphoric acid and Chloride Zinc on materials performances as activation reagent is favourable than sulphuric acid and potassium hydroxide, whether Sbet and iodine adsorption value or methylene blue adsorption value. Where after, combined with other advantages and disadvantages between the phosphoric acid and Chloride Zinc activation, the Chloride Zinc is selected as activation reagent finally. And utilized the orthogonal experiment and single factor experiment to research correlative effect factors of produced porous adsorbent derived from sewage sludge. 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 produced adsorbents is the concentration of activation reagent 3mol/L, pyrolysis temperature 850 ℃ and the pyrolysis dwell time 60 min. And utilized center complex design to research the effect of pyrolysis temperature and pyrolysis dwell time on the characteristics of adsorbent derived from sewage sludge, the simulation experimental results show that the correctness of the orthogonal experiment. And then, the function of the activation reagent ZnCl2 is worked out through thermal analysis apparatus, theexperimental result shows that the function of ZnCl2 is to accelerate the organic component of the sewage sludge wetness and swell, mucus dissolve and dissolution, the reagent solution penetrates to the interior of the sewage sludge and dissolves organic components to produce small opening, and the reagent ZnCl2 can promote the H and O atom production and be separated to become H2O, so more C can be reserved in the sewage sludge to increase the yield of the adsorbent.The thermal analysis apparatus was utilized to study the pyrolysis characteristics of the sewage sludge with ZnCb activation sewage sludge and without ZnCh activation sewage sludge under N2 atmosphere, and combined with FTIR spectrum to research produced gases in all kinds of stages, the experimental results show that the three stages pyrolysis reactions appeared for sewage sludge pyrolysis without ZnCl2 activation, but the four stages pyrolysis reaction appeared for ZnCb activation sewage sludge, and then the pyrolysis mechanism were studied through combined FTIR, simultaneity, the differential coefficient method was applied to question the reaction mechanism functions.The performances of the adsorbent derived from sewage sludge through chemical activation method are mainly affected by the characteristic parameters of the adsorbent including the appearance, shape and the acidic and basic characteristic change and so on. So the keys of the next research are the analysis of characteristic parameters. The experiment shows that the appearance, shape and the acidic and basic characteristics change obviously when pyrolysis temperature changed, these parameters relate to pyrolysis temperature, when the temperature is low, the acidic groups are favorite, and when the pyrolysis temperature is high, the basic groups are favorite. The porous characteristics of adsorbent derived from sewage sludge can be represented through N2 adsorption isotherm, and the porous characteristics are related to pyrolysis temperature, pyrolysis dwell time and the concentration of activation reagent. According to pore diameter distributing curve, it can be obtained that the pore diameter of adsorbent derived from sewage sludge is mainly mesporous. And utilized related apparatus to measure adsorbent density, it is found that the true density is 2.8 g/cm3, the Sbet area is 347 m2/g, the total porous volume is 0.289 cmVg and 0.312cm3/g before and after through hydrochloric acid rinse, respectively, and the microporous volume is 0.0876 cm / g and 0.098 cm3 / g, respectively, before and after through hydrochloric acid rinse, and...