| With rapid development of China’s economic, the environmental problem is even more worse, combined with the very uneven distribution of water resources,and the serious water shortages in some areas,pulse with the country’s domestic water and industrial wastewater discharge standards has been improving, so the efforts to treatment sewage increase and imminent. In water treatment technology, flocculation and sedimentation technology is the most common method, because it has the advantages of simple, effective, and easy operation. The flocculant is the key of flocculation and sedimentation technology, it directly affect the water quality, so it is critica to study the preparation of flocculation, it has been a hot research for scholars.Firstly, this subject do the research of Poly-Silicate-Aluminum-Zinc (PSAZS) flocculant on the basis of Poly Silicate Aluminum and zinc. The effect of SiO2containing,pH, activating reaction time, the (Al+Zn)/Si and Al/Zn molar rate were investigated on the basis of orthogonal experiments and single factor experiments. The results indicated the optimum condition was3%SiO2containing, pH=3,85min of activating reactions time,(Al+Zn)/Si=1.5and Al/Zn=2,The optimum adding quantity of PSAZS is3mL/200mL. And the effect of pH was obvious and the second factor was SiO2content. The effect of (Al+Zn)/Si ratio, Al/Zn ratio and activiting reaction time were less. PSAZS comprehensive the polysilicate ability of aggregation, aluminum has big floc, zinc is non-toxic, environmentally friendly, floc settling velocity, etc. In treating the artificial simulation kaolin wastewater which turbidity is200mg/L, the turbidity removal efficiency is up to99%or more.Nanotechnology is a new and emerging technology, we used it in preparaing flocculants, so we choosed ultrasonic method to make PSAZS nanorized. As the same, with the orthogonal and single factor method, the Three factors Sodium Stearate Surface active agent containing, Ultrasonic frequency, Ultrasonic time which effects the nanometer process was investigated. The results indicated the optimum condition which Nano-PSAZS was prepared was0.1%surface active agent Sodium Stearate containing,40kHz ultrasonic frequency and60min ultrasonic time. And the effect of ultrasonic time was obvious and the second factor was ultrasonic frequency.The effect of added surface active agent was little. Nano-PSAZS combination the advantage of PSAZS and nanomaterials which has the characteristic of much surface atoms, larger surface area, higher sepecific surface energy. In treating the artificial simulation kaolin wastewater which turbidity is300mg/L, the turbidity removal efficiency is up to99%or more, and its performance is stable, after aging for two months,the flocculation effect is still maintained at about96.8%, three months later it not come to gel.The ESEM and FT-IR were used in morphology characterization. The results indicated the aluminum and zinc added to the polysilicate, it is not a simple mixing, but the polycondensation and the complexing reaction occurred, generating to a bigger macromolecular polymer. Si contribute to extension the molecular chain, aluminum and zinc can help to generate a chain and network structure, being this it can better play the role in adsorping,bridging and networkThe removal of turbidity and color in a dyeing wastewate was investigated. The results show that the flocculant effect was good when the pH between6and9, this indicated the Nano-PSAZS has a wider used pH range. It also pay a role in neutralization, adsorping,bridging and network, the turbidity removal efficiency is up to97%or more, the color removal efficiency is up to94%or more. |
PDF Full Text Request