| Summary: | 碩士 === 國立中央大學 === 環境工程研究所 === 101 === The main purpose of this study was to investigate the fluoride wastewater in the order of different calcium chloride dosing of calcium fluoride crystal structure and configuration differences, fixed calcium fluoride than 1.0, the pH value of 7.0, precipitated calcium fluoride, chemical coagulation and sedimentation way, and add different doses of coagulant aid coagulant, to investigate the optimal treatment dose, the density of the particles of calcium fluoride crystal flocculation after coagulation carrier the size of the gap, the crystal grain nuclear re-growth factors also affect the size of the calcium fluoride crystals with fluoride ion removal efficiency.
The experimental results show that the first plus calcium chloride and then adjusted to pH water samples clear than the first pH adjustment coupled with calcium chloride, and by electron microscopy (SEM) images shown before adding calcium chloride and then adjusted to pH fluoride calcium crystal structure is real dense complete and can be found at the bottom of the stirred tank crystals generated. Better fluoride ion removal coagulant, polyacrylic acid (PAA) in a dose of 10 mg / L, then there is a significant downward trend in water samples of suspended solids (SS) and turbidity; using poly aluminum chloride (PACl) as coagulant, at a dose of 15 mg / L may also better fluoride ion removal, water samples poly aluminum chloride to remove the colloidal stability of the main mechanism for the adsorption and electrical and the precipitation mix In addition, while the precipitation mix in addition to aluminum hydroxide floc formation and to increase the chance of collision of the particles, when the particles are large enough to cause the particles flocculation together and settlement, in order to increase the removal efficiency.
To handle most of the fluorine-containing wastewater PACl with PAA, first PACl to stabilize, and then add the PAA floc effective to grow, to increase the performance of solid-liquid separation in water samples, so that it can effectively precipitate, suspended solids and turbidity degree, there is a significant downward trend, this trend is caused by the the water samples PAA or PACl Pharmacy segment dosing the floc formation from electrical and bridging mechanism cohesion into precipitation mix in addition to capturing the form.
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