Study On Development And Application Of Inorganic Mineral Materials Flocculants

At present, the more widely used flocculant is polyaluminium chloride (PAC).Because of its losse flocs structure, easy to float, poor sedimentation performance, certain residues in the water and other shortcomings,study and development of safe and efficient coagulants has been an important research field at home and abroad, and also, such research work which is of great significance.Based on the comprehensive research group on the basis of the study, the inorganic mineral materials flocculants was prepared by the raw mineral material vermiculite and modifier material acid. The raw vermiculite and inorganic mineral materials flocculants were characterized by SEM, XRD, FTIR and specific surface area analysis. Comparing the flocculation performance of inorganic mineral materials flocculants and their soluble salt and solid particle with those of PAC by detecting turbidity, Zeta potential and settlement velocity of flocs. Inorganic mineral materials flocculants and PAC, CPAM be compounded to deal with the actual food wastewater, lake water and black and odorous water in order to explore the flocculation effect and sedimentation effect. In addition, the flocculation mechanism of self-made flocculant has been disscussed preliminarily.The raw vermiculite and self-made optimum coagulant were analyzed by SEM, XRD and specific surface area analysis. The results showed that the structure of self-made coagulant is similar to raw vermiculite, which shows a lamellar structure and the surface has aggregate and porous structure. The specific surface area is reducer than the raw material. After modified by acid, the hole structure of vermiculite is full of acid soluble substances,which can play a role of flocculation. The internal phase of vermiculite material elements has changed significantly when the acid modified, however, the inter-layer structure basically unchanged.Vermiculite flocculant obtained from separated solid particles and soluble salts of two components. Experiments show that solid particles have no impact on flocculation. While the soluble salt can produce larger alum, but the floc sedimentation performance is worse than the vermiculite flocculant, and the precipitated water sample also suspends some tiny flocs. The optimum dosage of the soluble salt was 200 mg/L, the zeta potential was 0.1 mV and the turbidity removal rate was 97.8%. The combination of vermiculite flocculant and PAC improved the flocculation effect of PAC alone. It can effectively reduce the flocs volume and improve the settlement velocity of flocs. When half of the optimum dosage was combined, the flocculation volume was only one-third of the PAC after 30 minutes of settling. Compound effect is very remarkable. The vermiculite flocculant after acid modification has very good flocculation effect, and flocculation effect is almost as same as PAC flocculant. At the same time, vermiculite flocculants have more advantages than PACs.Such as, the alum formed quickly in water sample, with a quick settlement and the flocs are dense. Does not increase the complexity of water samples and has no secondary pollution.In practice, vermiculite flocculant is used alone, or compound with the PAC and CPAM,both have a good flocculation effect.The flocculation mechanism of vermiculite flocculant is synergistic effect with the neutralization effect of soluble salt on colloid, and the van der Waals attraction of the solid particles to the desorbed particles.