| In this article, I have studied several kinds of different methods of reducing the CODcr of black-liquor of straw pulping, and various kinds of factors, which influence the efficiency in the course of treatment. The course of studying can be divided into two parts.The first part is about acid recovery, flocculation and emulsion liquid membrane to get rid of the organic matter of black-liquor of straw pulping mainly, the purpose is to choose suitable method and the best response condition to reduce the CODcr of the black-liquor of straw pulp papermaking. The experimental results shows: Adopt sulphuric acid as acid recovery pharmaceutical, pH=2.0, storing time between 1.5-2.0 hours, and deal with the black liquid under the normal atmospheric temperature, can reach the best result; The treatment of the filtrate of black papermaking liquor after lignin extraction in Acid Precipitation has been studied with polyaluminium chloride as coagulant, when the dosage of PAC is 200mg/L waste water, pH =7, mix terms of 30 minutes, the getting rid of efficiency of CODcr can be up to 55.6%; Emulsion liquid membrane was applied for treatment of paper mill black liquor after acid recovery, experimental results indicate that the system of emulsion liquid membrane was steady as it consisted of kerosene,OP-4 and H2SO4,the removal efficiency of CODcr is up to 48.2% when OP-4 is 3g/100mL kerosene, H2SO4 is 1 mol/L, the Rew=1:10,and Roi=1:1. Through experiment I found that efficiency of dealing with black liquid of papermaking after the acid analyses, flocculation and emulsion liquid membrane is not high, CODcr of the treated incomplete liquid is still above 10,000, so sections of water is it go on the next experiment to surface in simulation two biochemistry treated after incomplete liquid dilute after analyzing acid.The second part focuses on the treatment for the low-consistency black liquor of straw papering by rectorite and goethite. When 50g rectorite was used for 1 liter wastewater, pH=4.0, absorb time is 60 minutes, the efficiency of absorbing of the waste water is best; When 35ggoethite was used for I liter organic-containing solution with 400 mg ? L-1 of cod, pH=6.0,t=60 minutes the absorption amount was 7.76mgCOD . g/L, the absorption rate was 68.89%.; According to the DTA analysis and experimental results, the temperature keeps in 280℃ is suit for rectorite desorption, the first desorption rate can up to 78.4% , but the absorb capability dropped after several desorption; 310℃ is the best desorption temperature for goethite, it's desorption rate is more than 95% after once desorption, and the goethite has higher efficiency of absorption after desorption three times, so it prove that goethite can be repeat utilize in absorption waste water , it is totally possible to apply the goethite to produce actually. |
