Study Of Imitation Enzymatic Treatment On Post Treatment Wastewater Of Pulp And Paper Mills

Pulp and paper is a high water consumption industry, and water pollution is relatively serious, which has became an obstacle in the development of papermaking industry. Improving the quality of treated wastewater is the best way to solve this problem, meanwhile, it can achieve the recycling of wastewater. Pulping and papermaking wastewater has characteristics of complexity and poor biodegradability. After the traditional multi-times processing, the wastewater of pulp and paper still have a high chemical oxygen demand,color and toxicity. With the promulgation of the new national wastewater standards, the advanced treatment becomes necessary.Imitation enzymes and enzyme have the advantages of efficiency, specificity and stability, also have a high adaptability to the environment. Biomimetic is an effective way for papermaking industry to achieve the goal of green chemistry.The preparation of Fe-CA was firstly studied in this paper. By studying the effects of several factors on the ferrous chelation rate and product yield, the optimum conditions for the preparation of Fe-CA are as follows:the ligand ratio=2:l,the initial of pH=5-5.5,the reaction temperature50℃, the reaction time40min. The Fe-CA catalyst which was prepared under the optimum conditions,its ferrous iron chelating was81.2%, the product yield was64.5%. In the last, infrared and thermal gravimetric analysis were conducted on the chelates,which proved the synthesis of chelates and the absence of free glycine.In this paper, we chose Fe-CA which was prepared under the optimal conditions as the catalyst. In order to remove color of the wastewater, H2O2dosage, Fe-CA dosage, initial pH, reaction time, reaction temperature and other factors that has an important effect on imitation enzyme treatment have been studied and optimized. Through single factor experiments,optimization of treatment process is:the dosage of H2O2=545.4mg/L, the dosage of Fe-CA=131mg/L, the initial pH=7.0, the reaction time=40min, the reaction temperature=25℃. By orthogonal experiments,we determined the order of these main influencing factors as follows:H2O2dosage> Fe-CA dosage> initial pH> reaction time. Under the optimal experimental conditions, the chroma is about32.6C.U.,rate of removal is about83%, showing that the method has a good control on chroma. The chroma of treated water has a good stability. Since the catalytic center does not have immobilization treatment, which cause the catalyst can not be separated. Therefore, the CODcr of treated wastewater is much higher than the actual value, about200mg/L. By immobilized treatment, it is expected that the CODCr of treated wastewater can be dropped significantly with the catalyst separation. The final pH of treated wastewater is7.2, which closed to neutral, and it is beneficial to reuse and disposal.In this paper, GC-MS analysis of dichloromethane extracts are studied about the treated and untreated wastewater, showing that the total species of organic matter in the wastewater before and after treatment, and most of the organic content which have not been detected or significantly reduced were:alcohols,phenols and benzene derivatives,unsaturated acids and amines etc.