Treatment Of Black Liquor In The Cottonseed Meal Pulping Process By Micro-electrolysis Method

Cotton pulp black liquor, a high concentration organic wastewater, is the difficulty of sewage treatment in pulp and paper industry. In this paper, micro-electrolysis method, micro-electrolysis - electro-catalytic oxidation and micro-electrolytic flocculation method have been used for the treatment of cotton pulp black liquor.When micro-electrolysis method was used for the treatment of cotton pulp black liquor, the cathode material, iron-carbon ratio, the amount of iron-carbon, reaction time, pH and aeration conditions were studied.The experiment examined the effect of cotton pulp black liquor COD removal rate and decolorization rate. The results showed that activated carbon was obtained for the best cathode material of micro-electrolysis method, and the best treatment process parameters were, iron-carbon ratio 1:1, the amount of iron-carbon 0.4g/mL, micro-electrolysis time 120min, pH = 3, aeration 0.4L/min. At this time, COD removal rate reached 86.5%, and decolorization rate was 94.3%.To further enhance the treatment efficiency, reducing processing costs, micro-electrolysis - electro-catalytic oxidation of compound treatment was adopted. Through orthogonal experiments, the optimum parameters were, iron-carbon capacity 50g/L, current density 5.0 mA/cm2, the reaction time 40min, electrolyte dosage 5g/L, pH = 11. At this time, COD removal rate reached 95.4%, and decolorization rate was 89.2%.Studies showed dosage of fly ash inorganic coagulant is 4mL/L. The decolorization rate was 93.7%, and COD removal rate reached 92.6%. At the same conditions, the PAC flocculation micro-electrolysis got the decolorization rate of 78.5%, and COD removal rate was 84.2%.Experiments showed that the use of micro-electrolysis - electro-catalytic oxidation of compound treatment had high COD removal efficiency, but power consumption and costly. Micro-electrolysis had high color removal, but needed to add acid. The COD removal and color removal rate of micro-electrolysis flocculation were all relatively high.