肝素钠生产废水处理及蛋白回收

Flocculation Treating Technique for Recovering Proteins from Casing-Heparin Wastewater

肝素钠生产废水中Cl-含量及盐度均较多,并且w(蛋白质)为1.68%,ρ(CODCr)为31 968 mg/g,处理难度大.为探究其净化和回收蛋白的方法,首先对FeCl_3·6H_2O、Fe SO4·7H2O、KAl(SO4)·12H2O进行粗筛,选择FeCl_3·6H_2O为无害蛋白絮凝剂;再通过单因素试验和Box-Benhnken-Design响应面法,考察了FeCl_3·6H_2O投加量、膨润土投加量、硅藻土投加量及p H对蛋白沉淀量的影响及交互作用;建立了蛋白回收的数学模型.结果表明,各因素对蛋白沉淀量的影响为:X2X4(硅藻土投加量与p H的交互项)>X4(硅藻土投加量)>X1X3(FeCl_3·6H_2O投加量与膨润土的交互项)>X1(FeCl_3·6H_2O投加量)>X1X4(FeCl_3·6H_2O投加量与硅藻土投加量的交互项);在最佳反应条件(p H为7.5,FeCl_3·6H_2O添加量为0.38%,膨润土投加量为1.90%,硅藻土添加量为4.25%)下蛋白沉淀量达0.82%,与预测值的偏差为3.50%.研究显示,在最佳反应条件下CODCr去除率达80.94%,减轻了废水后期的处理难度.

Large volumes of wastewater containing proteins, salts and C1^- are produced in the process of raw heparin extraction. Wastewater containing 1.68% protein and bearing CODer above 31,968 mg/L is generally treated chemically or biologically with increasing costs. Protein represents a valuable by-product that can be used in feed production. To reduce treatment costs and recover crude protein concurrently,the process parameters for optimizing protein recovery from wastewater of raw heparin production using harmless flocculants were investigated. First,the harmless flocculants were screened, then simple-factor experiment and response surface methodology （RSM） were employed to determine and to optimize process parameters including pH and floeculants such as FeCl3·6H20, bentonite and celite. Finally,a mathematical model of protein recovery was developed. The results suggested that the optimal process parameters were FeC13 · 6H20 O. 38% ,pH 7.5 ,bentonite 1.90% and celite 4.25% ,which resulted in O. 82% protein recovery. Under the optimal treatment,the wastewater became clear and CODer removal rate was up to 80.94%. After extracting with harmless flocculant, the gray, feculent and stinking wastewater became clean and colorless,pellucid and odorless. The study demonstrated that harmless floeculant precipitation is a new,green and easy as well as efficient method for protein extraction from heparin waste water.